Prolonged intra-aortic balloon pump support in biventricular heart failure induces right ventricular reverse remodeling.

PubMed

Ntalianis, Argyrios; Kapelios, Chris J; Kanakakis, John; Repasos, Evangelos; Pantsios, Christos; Nana, Emmeleia; Kontogiannis, Christos; Malliaras, Konstantinos; Tsamatsoulis, Michael; Kaldara, Elisabeth; Charitos, Christos; Nanas, John N

2015-08-01

Right ventricular dysfunction is associated with high morbidity and mortality in candidates for left ventricular assist device (LVAD) implantation or cardiac transplantation. We examined the effects of prolonged intra-aortic balloon pump (IABP) support on right ventricular, renal and hepatic functions in patients presenting with end-stage heart failure. Between March 2008 and June 2013, fifteen patients (mean age = 49.5 years; 14 men) with end-stage systolic heart failure (HF), contraindications for any life saving procedure (conventional cardiac surgery, heart transplantation, LVAD implantation) and right ventricular dysfunction were supported with the IABP. The patients remained on IABP support for a mean of 73 ± 50 days (median 72, range of 13-155). We measured the echocardiographic and hemodynamic changes in right ventricular function, and the changes in serum creatinine and bilirubin concentrations before and during IABP support. Mean right atrial pressure decreased from 12.7 ± 6.5 to 3.8 ± 3.3 (P < 0.001) and pulmonary artery pressure decreased from 35.7 ± 10.6 to 25 ± 8.4 mmHg (P = 0.001), while cardiac index increased from 1.5 ± 0.4 to 2.2 ± 0.7 l/m(2)/min (P = 0.003) and right ventricular stroke work index from 485 ± 228 to 688 ± 237 mmHg × ml/m(2) (P = 0.043). Right ventricular end-diastolic diameter decreased from 34.0 ± 6.5 mm to 27.8 ± 6.2 mm (P < 0.001) and tricuspid annular systolic tissue Doppler velocity increased from 9.6 ± 2.4 cm/s to 11.1 ± 2.3 cm/s (P = 0.029). Serum creatinine and bilirubin decreased from 2.1 ± 1.3 to 1.4 ± 0.6 mg/dl and 2.0 ± 1.0 to 0.9 ± 0.5 mg/dl, respectively (P = 0.002 and P < 0.001, respectively). Prolonged IABP support of patients presenting with end-stage heart failure and right ventricular dysfunction induced significant improvement in right ventricular and peripheral organ function. Copyright © 2015. Published by Elsevier Ireland Ltd.

Experimental and numeric investigation of Impella pumps as cavopulmonary assistance for a failing Fontan.

PubMed

Haggerty, Christopher M; Fynn-Thompson, Francis; McElhinney, Doff B; Valente, Anne Marie; Saikrishnan, Neelakantan; Del Nido, Pedro J; Yoganathan, Ajit P

2012-09-01

This study sought to evaluate the performance of microaxial ventricular assist devices for the purposes of supporting failing Fontan physiology by decreasing central venous pressure. Three Abiomed Impella pumps (Abiomed, Inc, Danvers, Mass) were evaluated in a mock circulatory system of the Fontan circuit. The local response of pressures and flows to pump function was assessed as a function of pump speed and pulmonary vascular resistance at a high baseline central venous pressure. For one device, subsequent modeling studies were conducted using a lumped parameter model of the single ventricle circuit. The left ventricular devices (Impella 2.5, 5.0) were shown to be suboptimal as single device solutions for cavopulmonary support. The small area of these devices relative to vessel diameter led to significant flow recirculation without an obstructive separator in place. Furthermore, downstream pressure augmentation adversely affected the pressure in the superior vena cava. The use of 2 devices would be mandatory for successful support. The right-sided device (Impella RP), whose outflow was positioned in the left pulmonary artery, demonstrated decreased flow recirculation and did not impede superior caval venous flow. Although static pressure is still required to drive flow through the opposite lung, numeric modeling demonstrated the potential for modest but significant improvements in lowering the central venous pressure (2-8 mm Hg). Left-sided microaxial pumps are not well suited for cavopulmonary support because of severe flow recirculation and the need for multiple devices. The right-ventricular Impella device provides improved performance by directing flow into the pulmonary artery, resulting in modest decreases in central venous pressure. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Novel temporary left ventricular assist system with hydrodynamically levitated bearing pump for bridge to decision: initial preclinical assessment in a goat model.

PubMed

Kishimoto, Satoru; Takewa, Yoshiaki; Tsukiya, Tomonori; Mizuno, Toshihide; Date, Kazuma; Sumikura, Hirohito; Fujii, Yutaka; Ohnuma, Kentaro; Togo, Konomi; Katagiri, Nobumasa; Naito, Noritsugu; Kishimoto, Yuichiro; Nakamura, Yoshinobu; Nishimura, Motonobu; Tatsumi, Eisuke

2018-03-01

The management of heart failure patients presenting in a moribund state remains challenging, despite significant advances in the field of ventricular assist systems. Bridge to decision involves using temporary devices to stabilize the hemodynamic state of such patients while further assessment is performed and a decision can be made regarding patient management. We developed a new temporary left ventricular assist system employing a disposable centrifugal pump with a hydrodynamically levitated bearing. We used three adult goats (body weight, 58-68 kg) to investigate the 30-day performance and hemocompatibility of the newly developed left ventricular assist system, which included the pump, inflow and outflow cannulas, the extracorporeal circuit, and connectors. Hemodynamic, hematologic, and blood chemistry measurements were investigated as well as end-organ effect on necropsy. All goats survived for 30 days in good general condition. The blood pump was operated at a rotational speed of 3000-4500 rpm and a mean pump flow of 3.2 ± 0.6 L min. Excess hemolysis, observed in one goat, was due to the inadequate increase in pump rotational speed in response to drainage insufficiency caused by continuous contact of the inflow cannula tip with the left ventricular septal wall in the early days after surgery. At necropsy, no thrombus was noted in the pump, and no damage caused by mechanical contact was found on the bearing. The newly developed temporary left ventricular assist system using a disposable centrifugal pump with hydrodynamic bearing demonstrated consistent and satisfactory hemodynamic performance and hemocompatibility in the goat model.

Longitudinal and transverse right ventricular function in pulmonary hypertension: cardiovascular magnetic resonance imaging study from the ASPIRE registry

PubMed Central

Rajaram, Smitha; Capener, Dave; Elliot, Charlie; Condliffe, Robin; Wild, Jim M.; Kiely, David G.

2015-01-01

Abstract Right ventricular (RV) function is a strong predictor of outcome in cardiovascular diseases. Two components of RV function, longitudinal and transverse motion, have been investigated in pulmonary hypertension (PH). However, their individual clinical significance remains uncertain. The aim of this study was to determine the factors associated with transverse and longitudinal RV motion in patients with PH. In 149 treatment-naive patients with PH and 16 patients with suspected PH found to have mean pulmonary arterial pressure of <20 mmHg, cardiovascular magnetic resonance imaging was performed within 24 hours of right heart catheterization. In patients with PH, fractional longitudinal motion (fractional tricuspid annulus to apex distance [f-TAAD]) was significantly greater than fractional transverse motion (fractional septum to free wall distance [f-SFD]; P = 0.002). In patients without PH, no significant difference between f-SFD and f-TAAD was identified (P = 0.442). Longitudinal RV motion was singularly associated with RV ejection fraction independent of age, invasive hemodynamics, and cardiac magnetic resonance measurements (P = 0.024). In contrast, transverse RV motion was independently associated with left ventricular eccentricity (P = 0.036) in addition to RV ejection fraction (P = 0.014). In conclusion, RV motion is significantly greater in the longitudinal direction in patients with PH, whereas patients without PH have equal contributions of transverse and longitudinal motion. Longitudinal RV motion is primarily associated with global RV pump function in PH. Transverse RV motion not only reflects global pump function but is independently influenced by ventricular interaction in patients with PH. PMID:26401257

Longitudinal and transverse right ventricular function in pulmonary hypertension: cardiovascular magnetic resonance imaging study from the ASPIRE registry.

PubMed

Swift, Andrew J; Rajaram, Smitha; Capener, Dave; Elliot, Charlie; Condliffe, Robin; Wild, Jim M; Kiely, David G

2015-09-01

Right ventricular (RV) function is a strong predictor of outcome in cardiovascular diseases. Two components of RV function, longitudinal and transverse motion, have been investigated in pulmonary hypertension (PH). However, their individual clinical significance remains uncertain. The aim of this study was to determine the factors associated with transverse and longitudinal RV motion in patients with PH. In 149 treatment-naive patients with PH and 16 patients with suspected PH found to have mean pulmonary arterial pressure of <20 mmHg, cardiovascular magnetic resonance imaging was performed within 24 hours of right heart catheterization. In patients with PH, fractional longitudinal motion (fractional tricuspid annulus to apex distance [f-TAAD]) was significantly greater than fractional transverse motion (fractional septum to free wall distance [f-SFD]; P = 0.002). In patients without PH, no significant difference between f-SFD and f-TAAD was identified (P = 0.442). Longitudinal RV motion was singularly associated with RV ejection fraction independent of age, invasive hemodynamics, and cardiac magnetic resonance measurements (P = 0.024). In contrast, transverse RV motion was independently associated with left ventricular eccentricity (P = 0.036) in addition to RV ejection fraction (P = 0.014). In conclusion, RV motion is significantly greater in the longitudinal direction in patients with PH, whereas patients without PH have equal contributions of transverse and longitudinal motion. Longitudinal RV motion is primarily associated with global RV pump function in PH. Transverse RV motion not only reflects global pump function but is independently influenced by ventricular interaction in patients with PH.

Cavopulmonary Anastomosis in a Patient With Arrhythmogenic Right Ventricular Cardiomyopathy With Severe Right Ventricular Dysfunction.

PubMed

Vaidyanathan, Swaminathan; Kothandam, Sivakumar; Kumar, Rajesh; Indrajith, Sujatha Desai; Agarwal, Ravi

2017-01-01

A 26-year-old lady presented with exertional dyspnea, palpitations, central cyanosis, and oxygen saturations of 80% in room air. Her electrocardiogram, echocardiogram, and cardiac magnetic resonance were diagnostic of arrhythmogenic right ventricular dysplasia. There was no documented ventricular arrhythmia or syncopal episodes and Holter recordings were repeatedly normal. Cardiac hemodynamics showed right to left shunt through atrial septal defect, low pulmonary blood flow, normal atrial pressures, and minimally elevated right ventricular end-diastolic pressures. Since her presenting symptoms and cyanosis were attributed to reduced pulmonary blood flow, she underwent off-pump cavopulmonary anastomosis between right superior vena cava and right pulmonary artery. As we intended to avoid the adverse effect of extracorporeal circulation on the myocardial function and pulmonary vasculature, we did not attempt to reduce the size of the atrial septal defect. Her postoperative period was uneventful; oxygen saturation improved to 89% with significant improvement in effort tolerance. At 18-month follow-up, there were no ventricular arrhythmias on surveillance. The clinical presentation of this disease may vary from serious arrhythmias warranting defibrillators and electrical ablations at one end to right ventricular pump failure warranting cardiomyoplasty or right ventricular exclusion procedures at the other end. However, when the presentation was unusual with severe cyanosis through a stretched foramen ovale leading to reduced pulmonary blood flows, Glenn shunt served as a good palliation and should be considered as one of the options in such patients.

Modelling the heart with the atrioventricular plane as a piston unit.

PubMed

Maksuti, Elira; Bjällmark, Anna; Broomé, Michael

2015-01-01

Medical imaging and clinical studies have proven that the heart pumps by means of minor outer volume changes and back-and-forth longitudinal movements in the atrioventricular (AV) region. The magnitude of AV-plane displacement has also shown to be a reliable index for diagnosis of heart failure. Despite this, AV-plane displacement is usually omitted from cardiovascular modelling. We present a lumped-parameter cardiac model in which the heart is described as a displacement pump with the AV plane functioning as a piston unit (AV piston). This unit is constructed of different upper and lower areas analogous with the difference in the atrial and ventricular cross-sections. The model output reproduces normal physiology, with a left ventricular pressure in the range of 8-130 mmHg, an atrial pressure of approximatly 9 mmHg, and an arterial pressure change between 75 mmHg and 130 mmHg. In addition, the model reproduces the direction of the main systolic and diastolic movements of the AV piston with realistic velocity magnitude (∼10 cm/s). Moreover, changes in the simulated systolic ventricular-contraction force influence diastolic filling, emphasizing the coupling between cardiac systolic and diastolic functions. The agreement between the simulation and normal physiology highlights the importance of myocardial longitudinal movements and of atrioventricular interactions in cardiac pumping. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Heartmate III: design and in vivo studies of a maglev centrifugal left ventricular assist device.

PubMed

Loree, H M; Bourque, K; Gernes, D B; Richardson, J S; Poirier, V L; Barletta, N; Fleischli, A; Foiera, G; Gempp, T M; Schoeb, R; Litwak, K N; Akimoto, T; Kameneva, M; Watach, M J; Litwak, P

2001-05-01

A compact implantable centrifugal left ventricular assist device (LVAD) (HeartMate III) featuring a magnetically levitated impeller is under development. The goal of our ongoing work is to demonstrate feasibility, low hemolysis, and low thrombogenicity of the titanium pump in chronic bovine in vivo studies. The LVAD is based on so-called bearingless motor technology and combines pump rotor, drive, and magnetic bearing functions in a single unit. The impeller is rotated (theta z) and levitated with both active (X, Y) and passive (Z, theta x, theta y) suspension. Six prototype systems have been built featuring an implantable titanium pump (69 mm diameter, 30 mm height) with textured blood contacting surfaces and extracorporeal electronics. The pumps were implanted in 9 calves (< or = 100 kg at implant) that were anticoagulated with Coumadin (2.5 < or = INR < or = 4.0) throughout the studies. Six studies were electively terminated (at 27-61 days), 1 study was terminated after the development of severe pneumonia and lung atelectasis (at 27 days) another study was terminated after cardiac arrest (at 2 days) while a final study is ongoing (at approximately 100 days). Mean pump flows ranged from 2 to 7 L/min, except for brief periods of exercise at 6 to 9 L/min. Plasma free hemoglobin ranged from 4 to 10 mg/dl. All measured biochemical indicators of end organ function remained within normal range. The pumps have met performance requirements in all 9 implants with acceptable hemolysis and no mechanical failures.

Off-pump grafting does not reduce postoperative pulmonary dysfunction.

PubMed

Izzat, Mohammad Bashar; Almohammad, Farouk; Raslan, Ahmad Fahed

2017-02-01

Objectives Pulmonary dysfunction is a recognized postoperative complication that may be linked to use of cardiopulmonary bypass. The off-pump technique of coronary artery bypass aims to avoid some of the complications that may be related to cardiopulmonary bypass. In this study, we compared the influence of on-pump or off-pump coronary artery bypass on pulmonary gas exchange following routine surgery. Methods Fifty patients (mean age 60.4 ± 8.4 years) with no preexisting lung disease and good left ventricular function undergoing primary coronary artery bypass grafting were prospectively randomized to undergo surgery with or without cardiopulmonary bypass. Alveolar/arterial oxygen pressure gradients were calculated prior to induction of anesthesia while the patients were breathing room air, and repeated postoperatively during mechanical ventilation and after extubation while inspiring 3 specific fractions of oxygen. Results Baseline preoperative arterial blood gases and alveolar/arterial oxygen pressure gradients were similar in both groups. At both postoperative stages, the partial pressure of arterial oxygen and alveolar/arterial oxygen pressure gradients increased with increasing fraction of inspired oxygen, but there were no statistically significant differences between patients who underwent surgery with or without cardiopulmonary bypass, either during ventilation or after extubation. Conclusions Off-pump surgery is not associated with superior pulmonary gas exchange in the early postoperative period following routine coronary artery bypass grafting in patients with good left ventricular function and no preexisting lung disease.

Intra-aortic balloon pumping in acute mitral regurgitation reduces aortic impedance and regurgitant fraction.

PubMed

Dekker, André L A J; Reesink, Koen D; van der Veen, Frederik H; van Ommen, G Vincent A; Geskes, Gijs G; Soemers, A Cecilia M; Maessen, Jos G

2003-04-01

Acute mitral regurgitation (MR) is present in 10% of patients presenting with cardiogenic shock. To stabilize these patients, intra-aortic balloon pumping (IABP) is recommended, but the mechanism of IABP support in these patients is unknown. This animal study was designed to describe the hemodynamic effect of intra-aortic balloon pumping during cardiogenic shock induced by acute MR. In eight calves, left ventricular pressure-volume loops, aortic and left atrial pressure, and aortic, carotid artery, and coronary blood flow were recorded. Acute MR (range 36%-79%) was created by placing a metal cage in the mitral valve. Hemodynamic data was obtained at control, during acute MR, and during acute MR with 1:1 IABP support. Acute MR caused a decrease in cardiac output (-32%, P = 0.018), blood pressure, and carotid artery flow, whereas left ventricular output (+127%, P = 0.018), end-diastolic volume, and left atrial pressure all significantly increased. Stroke work, ejection fraction, and coronary blood flow were not significantly changed, and no signs of ischemia were seen on the ECG. The IABP raised average cardiac output by 31% (P = 0.012) and significantly raised blood pressure and flow to the brain while decreasing systemic vascular resistance. Left ventricular function and mean coronary blood flow did not change, but diastolic coronary flow became more important as shown by the increase in diastolic fraction from 64% to 95%. (P = 0.028). Average MR dropped by 7.5% (P = 0.025). In conclusion, application of the IABP during acute MR lowers aortic impedance, resulting in less MR and more output toward the aorta without changing left ventricular function.

Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

PubMed

Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

Impact of left ventricular assist device speed adjustment on exercise tolerance and markers of wall stress.

PubMed

Hayward, Christopher S; Salamonsen, Robert; Keogh, Anne M; Woodard, John; Ayre, Peter; Prichard, Roslyn; Kotlyar, Eugene; Macdonald, Peter S; Jansz, Paul; Spratt, Phillip

2015-09-01

Left ventricular assist devices are crucial in rehabilitation of patients with end-stage heart failure. Whether cardiopulmonary function is enhanced with higher pump output is unknown. 10 patients (aged 39±16 years, mean±SD) underwent monitored adjustment of pump speed to determine minimum safe low speed and maximum safe high speed at rest. Patients were then randomized to these speed settings and underwent three 6-minute walk tests (6MWT) and symptom-limited cardiopulmonary stress tests (CPX) on separate days. Pump speed settings (low, normal and high) resulted in significantly different resting pump flows of 4.43±0.6, 5.03±0.94, and 5.72±1.2 l/min (P<.001). There was a significant enhancement of pump flows (greater at higher speed settings) with exercise (P<0.05). Increased pump speed was associated with a trend to increased 6MWT distance (P=.10); and CPX exercise time (p=.27). Maximum workload achieved and peak oxygen consumption were significantly different comparing low to high pump speed settings only (P<.05). N-terminal-pro-B-type natriuretic peptide release was significantly reduced at higher pump speed with exercise (P<.01). We have found that alteration of pump speed setting resulted in significant variation in estimated pump flow. The high-speed setting was associated with lower natriuretic hormone release consistent with lower myocardial wall stress. This did not, however, improve exercise tolerance.

[Initial experience with a new blood pump].

PubMed

Margreiter, R; Schwab, W; Klima, G; Koller, J; Baum, M; Dietrich, H; Hager, J; Königsrainer, A

1990-12-01

A new type of blood pump was tested in calves for 6 hours. The pump consists of a rigid housing with a trochoidal internal surface, an inlet and outlet, and two lateral walls. A two-corner piston rotating on an eccentric shaft, describes a trochoidal path, thus creating a gap seal, the gap measuring a constant 10-35 microns. The pump is driven by a watercooled DC motor. For right ventricular assist, a cannula is inserted into the right ventricle through the right atrium, and into the left ventricle for left ventricular assists. From a total of 10 experiments, two left ventricular assists, two right ventricular assists, and three biventricular assists were evaluated. The pump produced a pulsatile flow of 31 at 70 rpm. Energy requirements were 2.19 watts for left, 2.06 for right, and 7.26 for biventricular assists. Plasma hemoglobin remained as low as 10 mg/dl during monoventricular, and increased during biventricular assists to 20 mg/dl after 3 hours, and returned to 16 mg/dl after 6 hours. From these preliminary results it is concluded that this new rotary blood pump may be suitable as a circulatory assist device.

Rotacor: a new rotary blood pump.

PubMed

Margreiter, R; Schwab, W; Klima, G; Koller, J; Baum, M; Dietrich, H; Hager, J; Königsrainer, A

1990-01-01

A new rotary blood pump was tested in calves for 6 hr. The pump consists of a rigid housing with a trochoidal internal surface, an inlet and outlet, and two lateral walls. A two-corner piston rotates on an eccentric shaft in a trochoidal path, thus creating a gap seal. The pump is driven by a water-cooled DC motor. For right ventricular assist, a cannula was inserted into the right ventricle through the right atrium, and into the left ventricle for left ventricular assist. From a total of 10 experiments, two left ventricular assists, two right ventricular assists, and three biventricular assists were evaluated. The pump produced a pulsatile flow of 3 L at 70 rpm. Energy requirements were 2.19 watts for left, 2.06 for right, and 7.26 for biventricular assists. Plasma hemoglobin remained as low as 10 mg/dl during monoventricular, and increased during biventricular assists to 20 mg/dl after 3 hr, when it started to chop again; after 6 hr it was 16 mg/dl. From these preliminary results it is concluded that this new type of blood pump may be suitable as a circulatory assist device.

Mechanical ventilation and thoracic artificial lung assistance during mechanical circulatory support with PUCA pump: in silico study.

PubMed

De Lazzari, Claudio; Genuini, Igino; Quatember, Bernhard; Fedele, Francesco

2014-02-01

Patients assisted with left ventricular assist device (LVAD) may require prolonged mechanical ventilatory assistance secondary to postoperative respiratory failure. The goal of this work is the study of the interdependent effects LVAD like pulsatile catheter (PUCA) pump and mechanical ventilatory support or thoracic artificial lung (TAL), by the hemodynamic point of view, using a numerical simulator of the human cardiovascular system. In the simulator, different circulatory sections are described using lumped parameter models. Lumped parameter models have been designed to describe the hydrodynamic behavior of both PUCA pump and thoracic artificial lung. Ventricular behavior atrial and septum functions were reproduced using variable elastance model. Starting from simulated pathological conditions we studied the effects produced on some hemodynamic variables by simultaneous PUCA pump, thoracic artificial lung or mechanical ventilation assistance. Thoracic artificial lung was applied in parallel or in hybrid mode. The effects of mechanical ventilation have been simulated by changing mean intrathoracic pressure value from -4 mmHg to +5 mmHg. The hemodynamic variables observed during the simulations, in different assisted conditions, were: left and right ventricular end systolic (diastolic) volume, systolic/diastolic aortic pressure, mean pulmonary arterial pressure, left and right mean atrial pressure, mean systemic venous pressure and the total blood flow. Results show that the application of PUCA (without mechanical ventilatory assistance) increases the total blood flow, reduces the left ventricular end systolic volume and increases the diastolic aortic pressure. Parallel TAL assistance increases the right ventricular end diastolic (systolic) volume reduction both when PUCA is switched "ON" and both when PUCA is switched "OFF". By switching "OFF" the PUCA pump, it seems that parallel thoracic artificial lung assistance produces a greater cardiac output (respect to hybrid TAL assistance). Results concerning PUCA and TAL interaction produced by simulations cannot be compared with "in vivo" results since they are not presented in literature. But results concerning the effects produced by LVAD and mechanical ventilation have a trend consistent with those presented in literature. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Left atrial booster pump function is an independent predictor of subsequent life-threatening ventricular arrhythmias in non-ischaemic cardiomyopathy.

PubMed

Negishi, Kazuaki; Negishi, Tomoko; Zardkoohi, Omeed; Ching, Elizabeth A; Basu, Nivedita; Wilkoff, Bruce L; Popović, Zoran B; Marwick, Thomas H

2016-10-01

Left atrial (LA) function helps to preserve cardiac output and to control pulmonary capillary wedge pressure in the setting of left ventricular (LV) impairment, but little is known about the contribution of the LA function to ventricular arrhythmia. We sought whether LA booster pump function was associated with arrhythmias in patients undergoing primary prevention implantable cardioverter-defibrillator (ICD) implantation for non-ischaemic dilated cardiomyopathy (NICM), independent of global longitudinal strain (GLS) and mechanical dispersion (MD). We identified 124 NICM patients (56 ± 13, 67 male) who underwent echocardiography pre-ICD implantation for primary prevention. The main outcome measure was appropriate ICD therapy (anti-tachycardia pacing or shock). The mitral A-wave was used as an LA functional marker. MD was defined as standard deviation of time to peak strain of each segment. Over a median follow-up of 3.8 ± 2.2 years, 36 patients had appropriate ICD therapy, including 23 shocks. Patients with appropriate ICD therapy had lower A-wave velocity (P < 0.001), larger LA volume (P < 0.001), and impaired circumferential MD (P = 0.006), but similar ejection fraction (EF) (P = 0.40) and GLS (P = 0.11). In sequential Cox proportional hazards models, A-wave, E/A ratio, and GLS were significantly associated with outcomes, independent of age, sex, and cardiac resynchronization therapy defibrillator or left bundle branch block. In nested Cox models, mitral A-wave had a prognostic value incremental to models with LV systolic (EF and GLS) and diastolic functional parameters (E/A, E/e', and LA volume) and MD. LA booster pump function was an independent and incremental predictor of arrhythmias in NICM over GLS and MD, and may aid better risk stratification in this population. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Hemodynamics on abrupt stoppage of centrifugal pumps during left ventricular assist.

PubMed

Kono, S; Nishimura, K; Nishina, T; Akamatsu, T; Komeda, M

2000-01-01

A magnetically suspended centrifugal pump (MSCP), developed for long-term ventricular assist, is reliable and durable because it has no shaft or seal. However, with nonvalve pumps such as a MSCP, regurgitation occurs when they accidentally stop without cannula clamping. We investigated the hemodynamics during temporary stoppage of a MSCP being used as a left ventricular assist system (LVAS), comparing two inflow cannulation sites. In four sheep (weight, 35-45 kg), microspheres were injected into the left main coronary artery to induce heart failure. An outflow cannula was sutured onto the descending aorta, and two inflow cannulae were inserted into the left atrium and the left ventricle. The MSCP was stopped with both the left ventricular cannula and left atrial cannula clamped, and the hemodynamics and P-V loops were recorded. Each cannula was then unclamped in order, and similar parameters were recorded. LVEDP increased at unclamping of the left ventricular cannula (ULVC), and rose further at unclamping of the left atrial cannula (ULAC). Aortic pressure did not change at ULVC, but decreased at ULAC. The effective systemic flow that subtracted the regurgitant flow through the MSCP from left ventricular output was half at ULVC and almost 0 at ULAC. When stopping centrifugal pumps without circuit clamping, hemodynamic deterioration is less at ULVC than at ULAC. This finding suggests that left ventricular inflow cannulation is recommended to allow more time in emergency situations.

Off-pump coronary artery bypass surgery in selected patients is superior to the conventional approach for patients with severely depressed left ventricular function

PubMed Central

Caputti, Guido Marco; Palma, José Honório; Gaia, Diego Felipe; Buffolo, Enio

2011-01-01

OBJECTIVES: Patients with coronary artery disease and left ventricular dysfunction have high mortality when kept in clinical treatment. Coronary artery bypass grafting can improve survival and the quality of life. Recently, revascularization without cardiopulmonary bypass has been presented as a viable alternative. The aim of this study is to compare patients with left ventricular ejection fractions of less than 20% who underwent coronary artery bypass graft with or without cardiopulmonary bypass. METHODS: From January 2001 to December 2005, 217 nonrandomized, consecutive, and nonselected patients with an ejection fraction less than or equal to 20% underwent coronary artery bypass graft surgery with (112) or without (off-pump) (105) the use of cardiopulmonary bypass. We studied demographic, operative, and postoperative data. RESULTS: There were no demographic differences between groups. The outcome variables showed similar graft numbers in both groups. Mortality was 12.5% in the cardiopulmonary bypass group and 3.8% in the off-pump group. Postoperative complications were statistically different (cardiopulmonary bypass versus off-pump): total length of hospital stay (days)—11.3 vs. 7.2, length of ICU stay (days)—3.7 vs. 2.1, pulmonary complications—10.7% vs. 2.8%, intubation time (hours)—22 vs. 10, postoperative bleeding (mL)—654 vs. 440, acute renal failure—8.9% vs. 1.9% and left-ventricle ejection fraction before discharge—22% vs. 29%. CONCLUSION: Coronary artery bypass grafting without cardiopulmonary bypass in selected patients with severe left ventricular dysfunction is valid and safe and promotes less mortality and morbidity compared with conventional operations. PMID:22189729

Cora valveless pulsatile rotary pump: new design and control.

PubMed

Monties, J R; Trinkl, J; Mesana, T; Havlik, P J; Demunck, J L

1996-01-01

For decades, research for developing a totally implantable artificial ventricle has been carried on. For 4 to 5 years, two devices have been investigated clinically. For many years, we have studied a rotary (but not centrifugal) pump that furnishes pulsatile flow without a valve and does not need external venting or a compliance chamber. It is a hypocycloidal pump based on the principle of the Maillard-Wankel rotary compressor. Currently made of titanium, it is activated by an electrical brushless direct-current motor. The motor-pump unit is totally sealed and implantable, without noise or vibration. This pump was implanted as a left ventricular assist device in calves. The midterm experiments showed good hemodynamic function. The hemolysis was low, but serious problems were encountered: blood components collecting on the gear mechanism inside the rotor jammed the pump. We therefore redesigned the pump to seal the gear mechanism. We used a double system to seal the open end of the rotor cavity with components polished to superfine optical quality. In addition, we developed a control system based on the study of the predicted shape of the motor current. The new design is now underway. We hope to start chronic experiments again in a few months. If the problem of sealing the bearing could be solved, the Cora ventricle could be used as permanent totally implantable left ventricular assist device.

Cannula Tip With Integrated Volume Sensor for Rotary Blood Pump Control: Early-Stage Development.

PubMed

Cysyk, Joshua; Newswanger, Ray; Popjes, Eric; Pae, Walter; Jhun, Choon-Sik; Izer, Jenelle; Weiss, William; Rosenberg, Gerson

2018-05-10

The lack of direct measurement of left ventricular unloading is a significant impediment to the development of an automatic speed control system for continuous-flow left ventricular assist devices (cf-LVADs). We have developed an inlet cannula tip for cf-LVADs with integrated electrodes for volume sensing based on conductance. Four platinum-iridium ring electrodes were installed into grooves on a cannula body constructed from polyetheretherketone (PEEK). A sinusoidal current excitation waveform (250 μA pk-pk, 50 kHz) was applied across one pair of electrodes, and the conductance-dependent voltage was sensed across the second pair of electrodes. The conductance catheter was tested in an acute ovine model (n = 3) in conjunction with the HeartMate II rotary blood pump to provide circulatory support and unload the ventricle. Echocardiography was used to measure ventricular size during pump support for verification for the conductance measurements. The conductance measurements correlated linearly with the echocardiography dimension measurements more than the full range of pump support from minimum support to suction. This cannula tip will enable the development of automatic control systems to optimize pump support based on a real-time measurement of ventricular size.

Hemodynamic changes during displacement of the beating heart using epicardial stabilization for off-pump coronary artery bypass graft surgery.

PubMed

Mishra, Manisha; Malhotra, Rajneesh; Mishra, Anil; Meharwal, Zile Singh; Trehan, Naresh

2002-12-01

To evaluate the hemodynamic alterations during off-pump coronary artery bypass graft surgery to determine the degree of impairment caused and the techniques to rectify them. Prospective, observational cohort study performed from January 2000 through September 2000. Patients (n = 500) with coronary artery disease undergoing multivessel off-pump coronary artery bypass graft surgery using the Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, MN). Unstable patients with ongoing ischemia were excluded from the study. All patients were monitored with radial artery and pulmonary artery catheters and continuous transesophageal echocardiography monitoring with a multiplane transducer. The perioperative requirement of an intracoronary shunt, inotropes, or an intra-aortic balloon pump was noted. The effect of the Trendelenburg position and fluids on hemodynamics was observed. The need for defibrillation and institution of emergency cardiopulmonary bypass were major endpoints to determine the inability of the patient to tolerate displacement of the heart. Mean patient age was 59.3 +/- 11.6 years. There were 204 (40%) patients in the high-risk category; 54 (10.8%) patients had left ventricular ejection fraction <25%. The mean number of grafts was 2.7 +/- 0.8. Vertical displacement of the heart to access the lateral and inferior walls decreased the mean arterial pressure by 18 +/- 4% (p < 0.01), with a concomitant increase in central venous pressure of 66 +/- 18% (p < 0.001). The stroke volume and the cardiac index were reduced by 35.7 +/- 11% (p < 0.001) and 45 +/- 13% (p < 0.001). On transesophageal echocardiography, there was development of new regional wall motion abnormalities in 59.2% and a decrease in global left ventricular functions in 61.2%. The use of inotropes was highest during anastomosis on the posterior wall-78.4% compared with 21.9% for the anterior wall. An intra-aortic balloon pump was used in 55 (11.2%) patients, and 7 (0.71 %) patients had to be put on emergency CPB. The in-hospital mortality was 1.2%. Most patients had hemodynamic changes easily correctable by fluids and inotropes. Monitoring of left ventricular and right ventricular function by transesophageal echocardiography enhances safety of the procedure and is recommended. The use of the Octopus II tissue stabilizer proved to be a safe and versatile means to stabilize the heart during off-pump coronary artery bypass procedures, especially in high-risk patients. Copyright 2002, Elsevier Science (USA). All rights reserved.

Biomechanics of Cardiac Function

PubMed Central

Voorhees, Andrew P.; Han, Hai-Chao

2015-01-01

The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments. PMID:26426462

Physiological control of dual rotary pumps as a biventricular assist device using a master/slave approach.

PubMed

Stevens, Michael C; Wilson, Stephen; Bradley, Andrew; Fraser, John; Timms, Daniel

2014-09-01

Dual rotary left ventricular assist devices (LVADs) can provide biventricular mechanical support during heart failure. Coordination of left and right pump speeds is critical not only to avoid ventricular suction and to match cardiac output with demand, but also to ensure balanced systemic and pulmonary circulatory volumes. Physiological control systems for dual LVADs must meet these objectives across a variety of clinical scenarios by automatically adjusting left and right pump speeds to avoid catastrophic physiological consequences. In this study we evaluate a novel master/slave physiological control system for dual LVADs. The master controller is a Starling-like controller, which sets flow rate as a function of end-diastolic ventricular pressure (EDP). The slave controller then maintains a linear relationship between right and left EDPs. Both left/right and right/left master/slave combinations were evaluated by subjecting them to four clinical scenarios (rest, postural change, Valsalva maneuver, and exercise) simulated in a mock circulation loop. The controller's performance was compared to constant-rotational-speed control and two other dual LVAD control systems: dual constant inlet pressure and dual Frank-Starling control. The results showed that the master/slave physiological control system produced fewer suction events than constant-speed control (6 vs. 62 over a 7-min period). Left/right master/slave control had lower risk of pulmonary congestion than the other control systems, as indicated by lower maximum EDPs (15.1 vs. 25.2-28.4 mm Hg). During exercise, master/slave control increased total flow from 5.2 to 10.1 L/min, primarily due to an increase of left and right pump speed. Use of the left pump as the master resulted in fewer suction events and lower EDPs than when the right pump was master. Based on these results, master/slave control using the left pump as the master automatically adjusts pump speed to avoid suction and increases pump flow during exercise without causing pulmonary venous congestion. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Quantification of the relative contribution of the different right ventricular wall motion components to right ventricular ejection fraction: the ReVISION method.

PubMed

Lakatos, Bálint; Tősér, Zoltán; Tokodi, Márton; Doronina, Alexandra; Kosztin, Annamária; Muraru, Denisa; Badano, Luigi P; Kovács, Attila; Merkely, Béla

2017-03-27

Three major mechanisms contribute to right ventricular (RV) pump function: (i) shortening of the longitudinal axis with traction of the tricuspid annulus towards the apex; (ii) inward movement of the RV free wall; (iii) bulging of the interventricular septum into the RV and stretching the free wall over the septum. The relative contribution of the aforementioned mechanisms to RV pump function may change in different pathological conditions.Our aim was to develop a custom method to separately assess the extent of longitudinal, radial and anteroposterior displacement of the RV walls and to quantify their relative contribution to global RV ejection fraction using 3D data sets obtained by echocardiography.Accordingly, we decomposed the movement of the exported RV beutel wall in a vertex based manner. The volumes of the beutels accounting for the RV wall motion in only one direction (either longitudinal, radial, or anteroposterior) were calculated at each time frame using the signed tetrahedron method. Then, the relative contribution of the RV wall motion along the three different directions to global RV ejection fraction was calculated either as the ratio of the given direction's ejection fraction to global ejection fraction and as the frame-by-frame RV volume change (∆V/∆t) along the three motion directions.The ReVISION (Right VentrIcular Separate wall motIon quantificatiON) method may contribute to a better understanding of the pathophysiology of RV mechanical adaptations to different loading conditions and diseases.

Use of a Left Ventricular Assist Device as a Bridge to Transplantation in a Pediatric Patient

PubMed Central

Frazier, O.H.; Bricker, J. Timothy; Macris, Michael P.; Cooley, Denton A.

1989-01-01

Despite many advances in heart transplantation and in mechanical circulatory support, the benefits of staged cardiac transplantation have not been extended to the pediatric transplant recipient, chiefly because implantable circulatory assist devices are still too large. Extracorporeal devices, however, can overcome this impediment. Here we report the 1st case, to our knowledge, in which an extracorporeal left ventricular assist device has been used in a child to support circulation prior to cardiac transplantation. The patient was a 9-year-old boy in New York Heart Association functional class IV, with congestive heart failure as a result of idiopathic biventricular cardiomegaly. In mid-May of 1987, while awaiting a suitable donor, he suffered severe oliguria after an episode of circulatory arrest. Therefore we decided to maintain his circulation—and consequently his peripheral organ function—with an extracorporeal left ventricular assist device. After establishing cardiopulmonary bypass under normothermia and without cardiac arrest, we established flow from the left ventricle through a 36-Fr wire-reinforced straight cannula to a Biomedicus BP-80 centrifugal force pump, with return to the proximal ascending aorta through a 28-Fr wire-reinforced straight cannula. The patient's hemodynamic course under subsequent mechanical circulatory support was remarkably stable, with controllable systemic hypertension and no evidence of hemolysis. Although cardiac activity was minimal and systemic blood flow nonpulsatile, the patient's renal, pulmonary, and hepatic functions improved, and his peripheral circulation was well preserved. After 12 hours of support, a donor heart became available, and a routine orthotopic cardiac transplant was performed. Upon removal, the left ventricular assist device showed a small amount of thrombus formation. The patient's postoperative recovery has been easily manageable, and 20 months after transplant he enjoys unrestricted physical activity. We conclude that an extracorporeal left ventricular assist device can be used as a bridge to cardiac transplantation in children. Moreover, this application of a continuous force centrifugal pump without adverse effect encourages the conclusion that long-term maintenance of terminal heart disease patients might be possible through development of small, implantable pumps with the potential of lower power requirements and reduced thrombogenesis. (Texas Heart Institute Journal 1989;16:46-50) PMID:15227237

Pulsatile operation of a continuous-flow right ventricular assist device (RVAD) to improve vascular pulsatility

PubMed Central

Ng, Boon C.; Timms, Daniel; Cohn, William E.

2018-01-01

Despite the widespread acceptance of rotary blood pump (RBP) in clinical use over the past decades, the diminished flow pulsatility generated by a fixed speed RBP has been regarded as a potential factor that may lead to adverse events such as vasculature stiffening and hemorrhagic strokes. In this study, we investigate the feasibility of generating physiological pulse pressure in the pulmonary circulation by modulating the speed of a right ventricular assist device (RVAD) in a mock circulation loop. A rectangular pulse profile with predetermined pulse width has been implemented as the pump speed pattern with two different phase shifts (0% and 50%) with respect to the ventricular contraction. In addition, the performance of the speed modulation strategy has been assessed under different cardiovascular states, including variation in ventricular contractility and pulmonary arterial compliance. Our results indicated that the proposed pulse profile with optimised parameters (Apulse = 10000 rpm and ωmin = 3000 rpm) was able to generate pulmonary arterial pulse pressure within the physiological range (9–15 mmHg) while avoiding undesirable pump backflow under both co- and counter-pulsation modes. As compared to co-pulsation, stroke work was reduced by over 44% under counter-pulsation, suggesting that mechanical workload of the right ventricle can be efficiently mitigated through counter-pulsing the pump speed. Furthermore, our results showed that improved ventricular contractility could potentially lead to higher risk of ventricular suction and pump backflow, while stiffening of the pulmonary artery resulted in increased pulse pressure. In conclusion, the proposed speed modulation strategy produces pulsatile hemodynamics, which is more physiologic than continuous blood flow. The findings also provide valuable insight into the interaction between RVAD speed modulation and the pulmonary circulation under various cardiovascular states. PMID:29677212

An implantable centrifugal blood pump for long term circulatory support.

PubMed

Yamazaki, K; Litwak, P; Kormos, R L; Mori, T; Tagusari, O; Antaki, J F; Kameneva, M; Watach, M; Gordon, L; Umezu, M; Tomioka, J; Koyanagi, H; Griffith, B P

1997-01-01

A compact centrifugal blood pump was developed as an implantable left ventricular assist system. The impeller diameter is 40 mm and the pump dimensions are 55 x 64 mm. This first prototype was fabricated from titanium alloy, resulting in a pump weight of 400 g including a brushless DC motor. Weight of the second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon to improve blood compatibility. Flow rates of over 7 L/min against 100 mmHg pressure at 2,500 rpm with 9 W total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system ("Cool-Seal") is used as a shaft seal. In this seal system, seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. The purge fluid is continuously purified and sterilized by an ultrafiltration filter incorporated into the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular apex-descending aorta bypass was performed utilizing a PTFE (Polytetrafluoroethylene) vascular graft, with the pump placed in the left thoracic cavity. In two in vivo experiments, pump flow rate was maintained at 5-8 L/min, and pump power consumption remained stable at 9-10 W. All plasma free hemoglobin levels were measured at < 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (< 0.5 ml/ day). Both animals remain under observation after 162 and 91 days of continuous pump function.

Off-pump coronary artery bypass surgery in severe left ventricular dysfunction.

PubMed

Azarfarin, Rasoul; Pourafkari, Leili; Parvizi, Rezayat; Alizadehasl, Azin; Mahmoodian, Roghaiyeh

2010-02-01

Our aim was to examine hospital outcomes of coronary artery bypass surgery in patients with and without left ventricular dysfunction, with regard to the surgical technique (off- or on-pump). Between March 2007 and March 2008, 689 consecutive patients underwent isolated first-time coronary artery bypass; 127 had ejection fractions < or = 30% (group 1) and 562 had ejection fractions >30% (group 2). Data of preoperative risk profiles and hospital outcomes were collected prospectively. Off-pump operations were performed in 49 (38.6%) patients in group 1 and 196 (34.9%) in group 2. The incidences of infectious, neurologic, and cardiac complications postoperatively were significantly higher in group 1. In multivariate analysis, preoperative ejection fraction < or = 30% was found to be an independent risk factor for postoperative complications and hospital mortality. The subgroup of patients undergoing off-pump surgery in both groups had a significantly lower rate of total complications than those undergoing conventional on-pump operations, but no significant difference in mortality was observed between those undergoing off-pump or conventional surgery in either group. Off-pump surgery helped to limit the increased morbidity rate after coronary bypass in patients with ventricular dysfunction.

Analysis of baroreflex sensitivity during undulation pump ventricular assist device support.

PubMed

Liu, Hongjian; Shiraishi, Yasuyuki; Zhang, Xiumin; Song, Hojin; Saijo, Yoshifumi; Baba, Atsushi; Yambe, Tomoyuki; Abe, Yusuke; Imachi, Kou

2009-07-01

The aim of this study was to examine the baroreflex sensitivity (BRS), which involves the autonomic nervous system, in a goat with a chronically implanted undulation pump ventricular assist device (UPVAD). The UPVAD involved transforming the rotation of a brushless DC motor into an undulating motion by a disc attached via a special linking mechanism, and a jellyfish valve in the outflow cannula to prevent diastolic backflow. The pump was implanted into the thoracic cavity of a goat by a left thoracotomy, and the inflow and outflow cannulae were sutured to the apex of the left ventricle and to the descending aorta, respectively. The driving cable was wired percutaneously to an external controller. Electrocardiogram and hemodynamic waveforms were recorded at a sampling frequency of 1 kHz. BRS was determined when awake by the slope of the linear regression of R-R interval against mean arterial pressure changes, which were induced by the administration of methoxamine hydrochloride, both with continuous driving of the UPVAD as well as without assistance. BRS values during the UPVAD support and without assistance were 1.60 +/- 0.30 msec/mm Hg and 0.98 +/- 0.22 msec/mm Hg (n = 5, P < 0.05), respectively. BRS was significantly improved during left ventricular assistance. Therefore, UPVAD support might decrease sympathetic nerve activity and increase parasympathetic nerve activity to improve both microcirculation and organ function.

Prognostic role of cardiac power index in ambulatory patients with advanced heart failure.

PubMed

Grodin, Justin L; Mullens, Wilfried; Dupont, Matthias; Wu, Yuping; Taylor, David O; Starling, Randall C; Tang, W H Wilson

2015-07-01

Cardiac pump function is often quantified by left ventricular ejection fraction by various imaging modalities. As the heart is commonly conceptualized as a hydraulic pump, cardiac power describes the hydraulic function of the heart. We aim to describe the prognostic value of resting cardiac power index (CPI) in ambulatory patients with advanced heart failure. We calculated CPI in 495 sequential ambulatory patients with advanced heart failure who underwent invasive haemodynamic assessment with longitudinal follow-up of adverse outcomes (all-cause mortality, cardiac transplantation, or ventricular assist device placement). The median CPI was 0.44 W/m(2) (interquartile range 0.37, 0.52). Over a median of 3.3 years, there were 117 deaths, 104 transplants, and 20 ventricular assist device placements in our cohort. Diminished CPI (<0.44 W/m(2) ) was associated with increased adverse outcomes [hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.8-3.1, P < 0.0001). The prognostic value of CPI remained significant after adjustment for age, gender, pulmonary capillary wedge pressure, cardiac index, pulmonary vascular resistance, left ventricular ejection fraction, and creatinine [HR 1.5, 95% CI 1.03-2.3, P = 0.04). Furthermore, CPI can risk stratify independently of peak oxygen consumption (HR 2.2, 95% CI 1.4-3.4, P = 0.0003). Resting cardiac power index provides independent and incremental prediction in adverse outcomes beyond traditional haemodynamic and cardio-renal risk factors. © 2015 The Authors. European Journal of Heart Failure © 2015 European Society of Cardiology.

Effect of increasing pump speed during exercise on peak oxygen uptake in heart failure patients supported with a continuous-flow left ventricular assist device. A double-blind randomized study.

PubMed

Jung, Mette Holme; Hansen, Peter Bo; Sander, Kaare; Olsen, Peter Skov; Rossing, Kasper; Boesgaard, Soeren; Russell, Stuart D; Gustafsson, Finn

2014-04-01

Continuous-flow left ventricular assist device (CF-LVAD) implantation is associated with improved quality of life, but the effect on exercise capacity is less well documented. It is uncertain whether a fixed CF-LVAD pump speed, which allows for sufficient circulatory support at rest, remains adequate during exercise. The aim of this study was to evaluate the effects of fixed versus incremental pump speed on peak oxygen uptake (peak VO2) during a maximal exercise test. In CF-LVAD (HeartMate II) patients exercise testing measuring peak oxygen uptake (VO2) was performed on an ergometer bike twice in one day: once with fixed pump speed (testfix) and once with incremental pump speed (testinc). The order of testfix and testinc in each patient was determined by randomization. During testinc pump speed was increased from the baseline value by 400 rpm/2 min. Fourteen patients (aged 23–69 years) were included with a mean support duration of 465±483 days. Baseline CF-LVAD speed was 9357±238 rpm and during testinc speed was increased by a mean of 1486±775 rpm. Mean peak VO2 was significantly higher in testinc compared with testfix (15.4±5.9 mL/kg/min vs. 14.1±6.3 mL/kg/min; P=0.012), corresponding to a 9.2% increase. All exercise tests (n=28) were adequately performed with RER>1. Increasing pump speed during exercise augments peak VO2 in patients supported with CF-LVADs. An automatic speed-change function in future generations of CF-LVADs might improve functional capacity. © 2014 The Authors. European Journal of Heart Failure © 2014 European Society of Cardiology.

Outcomes of HeartWare Ventricular Assist System support in 141 patients: a single-centre experience.

PubMed

Wu, Long; Weng, Yu-Guo; Dong, Nian-Guo; Krabatsch, Thomas; Stepanenko, Alexander; Hennig, Ewald; Hetzer, Roland

2013-07-01

A third-generation ventricular assist device, the HeartWare Ventricular Assist System, has demonstrated its reliability and durability in animal models and clinical experience. However, studies of a large series of applications are still lacking. We evaluate the safety and efficacy of the HeartWare pump in 141 patients with end-stage heart failure at a single centre. A total of 141 patients (116 men and 25 women with a mean age of 52 years) in New York Heart Association (NYHA) Class IV received implantation of the HeartWare Ventricular Assist System between August 2009 and April 2011 at the Deutsches Herzzentrum Berlin. The outcomes were measured in terms of laboratory data, adverse events, NYHA functional class and survival during device support. The HeartWare system provided an adequate haemodynamic support for patients both inside and outside the hospital. NYHA class improved to I-II. Organ function and pulmonary vascular resistance improved significantly. In this cohort of patients, 14 patients underwent heart transplantation, one had had the device explanted following myocardial recovery, one had changed to another assist device, 81 were on ongoing support and 44 died. The overall actuarial survival rates at 6 and 12 months were 70 and 67%, respectively, and the 3-, 6- and 12-month survival rates on a left ventricular assist device (LVAD) support for bridge to transplantation patients were 82, 81 and 79%, respectively. Infection and bleeding were the main adverse events. Four patients underwent an LVAD exchange for pump thrombosis. The HeartWare system provides a safe and effective circulatory support in a population with a wide range of body surface areas, with a satisfactory actuarial survival time and an improved quality of life. It can be used for univentricular or biventricular support, being implanted into the pericardial space with simplified surgical techniques.

An implantable centrifugal blood pump with a recirculating purge system (Cool-Seal system).

PubMed

Yamazaki, K; Litwak, P; Tagusari, O; Mori, T; Kono, K; Kameneva, M; Watach, M; Gordon, L; Miyagishima, M; Tomioka, J; Umezu, M; Outa, E; Antaki, J F; Kormos, R L; Koyanagi, H; Griffith, B P

1998-06-01

A compact centrifugal blood pump has been developed as an implantable left ventricular assist system. The impeller diameter is 40 mm, and pump dimensions are 55 x 64 mm. This first prototype, fabricated from titanium alloy, resulted in a pump weight of 400 g including a brushless DC motor. The weight of a second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon (DLC) to improve blood compatibility. Flow rates of over 7 L/min against 100 mm Hg pressure at 2,500 rpm with 9 W total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system (Cool-Seal) is used for the shaft seal. In this seal system, the seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. Purge fluid is continuously purified and sterilized by an ultrafiltration unit which is incorporated in the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular (LV) apex descending aorta bypass was performed utilizing an expanded polytetrafluoroethylene (ePTFE) vascular graft with the pump placed in the left thoracic cavity. In 2 in vivo experiments, the pump flow rate was maintained at 5-9 L/min, and pump power consumption remained stable at 9-10 W. All plasma free Hb levels were measured at less than 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (<0.5 ml/day). In both calves, the pumps demonstrated trouble free continuous function over 6 month (200 days and 222 days).

Current randomized control trials, observational studies and meta analysis in off-pump coronary surgery.

PubMed

Parissis, Haralabos; Lau, Man Chi; Parissis, Mondrian; Lampridis, Savvas; Graham, Victoria; Al-Saudi, Reza; Mhandu, Peter

2015-12-17

The off-pump literature is divided into three eras: the "early phase" with results favouring off-pump surgery supported with randomized control trials (RCTs) mainly from Bristol, UK; an "intermediate phase" dominated by the results of the ROOBY trial and finally a more "contemporary phase" whereby the off/on-pump argument is unsettled. Although the literature has failed to project an overall superiority of off-pump versus on-pump surgery, nevertheless, small randomized control trials and large meta-analysis studies are concluding that the incidence of a stroke is less than 1 % when an aortic off-pump techniques (especially the non-touch technique) are advocated in patients with diseased ascending aorta. Furthermore, off-pump combined with hybrid procedures may lead to a reduction of adverse outcome in the aged high-risk population with concomitant poor left ventricular function and co-morbidities.The current review attempts to bring an insight onto the last ten years knowledge on the on/off-pump debate, with an aim to draw some clear conclusions in order to allow practitioners to reflect on the subject.

Assessment of hydraulic performance and biocompatibility of a MagLev centrifugal pump system designed for pediatric cardiac or cardiopulmonary support.

PubMed

Dasse, Kurt A; Gellman, Barry; Kameneva, Marina V; Woolley, Joshua R; Johnson, Carl A; Gempp, Thomas; Marks, John D; Kent, Stella; Koert, Andrew; Richardson, J Scott; Franklin, Steve; Snyder, Trevor A; Wearden, Peter; Wagner, William R; Gilbert, Richard J; Borovetz, Harvey S

2007-01-01

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the PediVAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to (1/4) in. For the expected range of pediatric flow (0.3-3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future.

Left Ventricular Free Wall Rupture in Acute Myocardial Infarction

PubMed Central

Amir, Offer; Smith, Ronald; Nishikawa, Akaira; Gregoric, Igor D.; Smart, Frank W.

2005-01-01

We describe a case of subacute left ventricular free wall rupture during acute myocardial infarction in a 68-year-old man. The diagnosis was confirmed by echocardiography. The patient was supported by an intra-aortic balloon pump until the ruptured wall could be successfully repaired by suturing and gluing a pericardial patch over the defect and bypassing the left anterior descending coronary artery with a vein graft. This case demonstrates that left ventricular free wall rupture is not always fatal and that early diagnosis and institution of intra-aortic balloon pump support in such patients can allow successful bridging to definitive emergency surgical therapy. PMID:16392235

Left Ventricular Assist Devices: The Adolescence of a Disruptive Technology.

PubMed

Pinney, Sean P

2015-10-01

Clinical outcomes for patients with advanced heart failure receiving left ventricular assist devices are driven by appropriate patient selection, refined surgical technique, and coordinated medical care. Perhaps even more important is innovative pump design. The introduction and widespread adoption of continuous-flow ventricular assist devices has led to a paradigm shift within the field of mechanical circulatory support, making the promise of lifetime device therapy closer to reality. The disruption caused by this new technology, on the one hand, produced meaningful improvements in patient survival and quality of life, but also introduced new clinical challenges, such as bleeding, pump thrombosis, and acquired valvular heart disease. Further evolution within this field will require financial investment to sustain innovation leading to a fully implantable, durable, and cost-effective pump for a larger segment of patients with advanced heart failure. Copyright © 2015 Elsevier Inc. All rights reserved.

Successful bridge to transplant in a highly sensitized patient with a complicated pump pocket infection.

PubMed

McGee, Edwin C; Cotts, William; Tambur, Anat R; Friedewald, John; Kim, John; O'Connell, John; Wallace, Suzanne; McCarthy, Patrick M

2008-05-01

A 32-year-old man with doxorubicin-induced cardiomyopathy presented in cardiogenic shock. He underwent placement of a Novacor (WorldHeart, Inc., Oakland, CA) left ventricular assist device as a bridge to transplant. Post-operatively he developed a pump pocket infection and dehiscence of his abdominal wound with exposure of the pump. This was treated with irrigation and drainage, antibiotic bead placement and flap closure. Both pre- and post-operative panel-reactive antibodies (PRA) were elevated. He underwent desensitization with intravenous immune globulin (IVIg), rituximab, mycophenolate mofetil and pre-operative plasmapheresis. A donor heart was identified and found to be acceptable by virtual crossmatch. He was transplanted and is doing well with normal graft function at >1 year post-operatively.

Changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations after off-pump treatment of mitral regurgitation with the Coapsys device.

PubMed

Fukamachi, Kiyotaka; Popović, Zoran B; Inoue, Masahiro; Doi, Kazuyoshi; Schenk, Soren; Ootaki, Yoshio; Kopcak, Michael W; McCarthy, Patrick M

2004-03-01

The objective of this study was to evaluate the changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations produced by the Myocor Coapsys device that has been developed to treat functional mitral regurgitation (MR) off-pump. The Coapsys device, which consists of anterior and posterior epicardial pads connected by a sub-valvular chord, was implanted in seven dogs with functional MR resulting from pacing induced cardiomyopathy. The Coapsys device was then sized by drawing the posterior leaflet and annulus toward the anterior leaflet. During sizing, MR grade was assessed using color flow Doppler echocardiography. Final device size was selected when MR was eliminated or minimized. Following implantation, heart failure was maintained by continued pacing for a period of 8 weeks. Mitral annular and left ventricular dimensions and left ventricular pressure-volume relations were evaluated by two-dimensional echocardiography and a conductance catheter, respectively, at pre-sizing, post-sizing, and after 8 weeks. All implants were performed on beating hearts without cardiopulmonary bypass. Mean MR grade was reduced from 2.9+/-0.7 at pre-sizing to 0.7+/-0.8 at post-sizing (P<0.001), and was maintained at 0.8+/-0.8 after 8 weeks (P<0.01). The septal-lateral dimensions were significantly reduced at both mitral annular level [2.4+/-0.2 cm at pre-sizing, 1.5+/-0.3 cm at post-sizing (P<0.001) and 1.8+/-0.3 cm after 8 weeks (P<0.05)] and mid-papillary level [4.1+/-0.4 cm at pre-sizing, 2.4+/-0.2 cm at post-sizing (P<0.001) and 3.3+/-0.4 cm after 8 weeks (P<0.001)]. The end-systolic pressure-volume relation shifted leftward at post-sizing with a significantly steeper slope (P=0.03). There was a significant (P=0.03) leftward shift of the end-diastolic pressure-volume relation at post-sizing. After 8 weeks, these changes in pressure-volume relations tended to return to pre-sizing relations. The Coapsys device significantly reduced MR by treating both the mitral annular dilatation and the papillary muscle displacement. Despite these significant dimensional changes, the Coapsys device did not negatively affect the left ventricular pressure-volume relations.

Impact of left atrial volume reduction concomitant with atrial fibrillation surgery on left atrial geometry and mechanical function.

PubMed

Marui, Akira; Saji, Yoshiaki; Nishina, Takeshi; Tadamura, Eiji; Kanao, Shotaro; Shimamoto, Takeshi; Sasahashi, Nozomu; Ikeda, Tadashi; Komeda, Masashi

2008-06-01

Left atrial geometry and mechanical functions exert a profound effect on left ventricular filling and overall cardiovascular performance. We sought to investigate the perioperative factors that influence left atrial geometry and mechanical functions after the Maze procedure in patients with refractory atrial fibrillation and left atrial enlargement. Seventy-four patients with atrial fibrillation and left atrial enlargement (diameter > or = 60 mm) underwent the Maze procedure in association with mitral valve surgery. The maximum left atrial volume and left atrial mechanical functions (booster pump, reservoir, and conduit function [%]) were calculated from the left atrial volume-cardiac cycle curves obtained by magnetic resonance imaging. A stepwise multiple regression analysis was performed to determine the independent variables that influenced the postoperative left atrial geometry and function. The multivariate analysis showed that left atrial reduction surgery concomitant with the Maze procedure and the postoperative maintenance of sinus rhythm were predominant independent variables for postoperative left atrial geometry and mechanical functions. Among the 58 patients who recovered sinus rhythm, the postoperative left atrial geometry and function were compared between patients with (VR group) and without (control group) left atrial volume reduction. At a mean follow-up period of 13.8 months, sinus rhythm recovery rate was better (85% vs 68%, P < .05) in the VR group and maximum left atrial volume was less (116 +/- 25 mL vs 287 +/- 73 mL, P < .001) than in the control group. The maximum left atrial volume reduced with time only in the VR group (reverse remodeling). Postoperative booster pump and reservoir function in the VR group were better than in the control group (25% +/- 6% vs 11% +/- 4% and 34% +/- 7% vs 16% +/- 4%, respectively, P < .001), whereas the conduit function in the VR group was lower than in the control group, indicating that the improvement of the booster pump and reservoir function compensated for the conduit function to left ventricular filling. Left atrial reduction concomitant with the Maze procedure helped restore both contraction (booster pump) and compliance (reservoir) of the left atrium and facilitated left atrial reverse remolding. Left atrial volume reduction and postoperative maintenance of sinus rhythm may be desirable in patients with refractory AF and left atrial enlargement.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device.

PubMed

Gohean, Jeffrey R; George, Mitchell J; Pate, Thomas D; Kurusz, Mark; Longoria, Raul G; Smalling, Richard W

2013-01-01

The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device

PubMed Central

Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

2012-01-01

The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

Off-pump repair of a post-infarct ventricular septal defect: the 'Hamburger procedure'

PubMed Central

Barker, Thomas A; Ng, Alexander; Morgan, Ian S

2006-01-01

We report a novel off-pump technique for the surgical closure of post-infarct ventricular septal defects (VSDs). The case report describes the peri-operative management of a 76 year old lady who underwent the 'Hamburger procedure' for closure of her apical VSD. Refractory cardiogenic shock meant that traditional patch repairs requiring cardiopulmonary bypass would be poorly tolerated. We show that echocardiography guided off-pump posterior-anterior septal plication is a safe, effective method for closing post-infarct VSDs in unstable patients. More experience is required to ascertain whether this technique will become an accepted alternative to patch repairs. PMID:16722552

Selective reduction of afterload in right heart assist therapy: a mock loop study†.

PubMed

Hsu, Po-Lin; Hatam, Nima; Unterkofler, Jan; Goetzenich, Andreas; McIntyre, Madeleine; Wong, Kai Chun; Egger, Christina; Schmitz-Rode, Thomas; Autschbach, Rüdiger; Steinseifer, Ulrich

2014-07-01

The treatment of right ventricular failure is closely linked to effects on pulmonary vascular resistance and thus the right ventricular (RV) afterload. Medical therapy includes afterload-decreasing drugs such as nitric oxide and prostacycline. However, current devices for mechanical unloading of the right ventricle aim at a decrease in preload increasing the pulmonary volume loading. In our concept study, we tested a minimally invasive right ventricular assist device (MIRVAD) that specifically reduces the afterload. The MIRVAD is supposed to be a foldable device for temporary transvascular placement in the pulmonary artery. We incorporated a MIRVAD prototype into a mock circulatory loop that can reproduce haemodynamic interaction between the pump and the physiological system. Pulmonary hypertension (PH), right heart failure (RHF) and MIRVAD-assisted cases were simulated. The key haemodynamic parameters for RV unloading were recorded. Mock loop simulation attested to a sufficient right ventricular unloading by serial application of a miniaturized impeller pump in the pulmonary artery. The afterload, represented by the pulmonary arterial root pressure, was recovered to the healthy range (32.62-10.93 mmHg) for the simulated PH case. In the simulated RHF case, the impaired pulmonary perfusion increased from 43.4 to 88.8% of the healthy level and the total ventricular work reduced from 0.381 to 0.197 J at a pump speed of 3500 rpm. At pump speeds higher than 3500 rpm, the pulmonary valve remains constantly open and the right ventricular configuration changes into a simple perfused hollow body. The feasibility of RV unloading by a selective decrease in RV afterload was proved in principle. By alternation of the pump speed, gradual reloading in sense of a myocardial training may be achieved. The results will be validated by future animal trials where the relationship between the level of support and pulmonary vascular pressure can be investigated in vivo. Further device design concerning foldable impeller leaflets will be carried out. At a final stage, the crimped version is supposed to reach a size below 1 cm to facilitate minimally invasive insertion. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Ventricular assist devices in pediatrics

PubMed Central

Fuchs, A; Netz, H

2001-01-01

The implantation of a mechanical circulatory device for end-stage ventricular failure is a possible therapeutic approach in adult and pediatric cardiac surgery and cardiology. The aim of this article is to present mechanical circulatory assist devices used in infants and children with special emphasis on extracorporeal membrane oxygenation, Berlin Heart assist device, centrifugal pump and Medos assist device. The success of long-term support with implantable ventricular assist devices in adults and children has led to their increasing use as a bridge to transplantation in patients with otherwise non-treatable left ventricular failure, by transforming a terminal phase heart condition into a treatable cardiopathy. Such therapy allows rehabilitation of patients before elective cardiac transplantation (by removing contraindications to transplantation mainly represented by organ impairment) or acting as a bridge to recovery of the native left ventricular function (depending on underlying cardiac disease). Treatment may also involve permanent device implantation when cardiac transplantation is contraindicated. Indications for the implantation of assisted circulation include all states of cardiac failure that are reversible within a variable period of time or that require heart transplantation. This article will address the current status of ventricular assist devices by examining historical aspects of its development, current technical issues and clinical features of pediatric ventricular assist devices, including indications and contraindications for support. PMID:22368605

Suction prevention and physiologic control of continuous flow left ventricular assist devices using intrinsic pump parameters.

PubMed

Wang, Yu; Koenig, Steven C; Slaughter, Mark S; Giridharan, Guruprasad A

2015-01-01

The risk for left ventricular (LV) suction during left ventricular assist devices (LVAD) support has been a clinical concern. Current development efforts suggest LVAD suction prevention and physiologic control algorithms may require chronic implantation of pressure or flow sensors, which can be unreliable because of baseline drift and short lifespan. To overcome this limitation, we designed a sensorless suction prevention and physiologic control (eSPPC) algorithm that only requires LVAD intrinsic parameters (pump speed and power). Two gain-scheduled, proportional-integral controllers maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction while maintaining an average reference differential pressure (ΔP) between the LV and aorta. ΔRPM is calculated from noisy pump speed measurements that are low-pass filtered, and ΔP is estimated using an extended Kalman filter. Efficacy and robustness of the eSPPC algorithm were evaluated in silico during simulated rest and exercise test conditions for 1) excessive ΔP setpoint (ES); 2) rapid eightfold increase in pulmonary vascular resistance (PVR); and 3) ES and PVR. Simulated hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) using only intrinsic pump parameters showed the feasibility of our proposed eSPPC algorithm in preventing LV suction for all test conditions.

Mechanical Circulatory Support of the Right Ventricle for Adult and Pediatric Patients With Heart Failure.

PubMed

Chopski, Steven G; Murad, Nohra M; Fox, Carson S; Stevens, Randy M; Throckmorton, Amy L

2018-05-10

The clinical implementation of mechanical circulatory assistance for a significantly dysfunctional or failing left ventricle as a bridge-to-transplant or bridge-to-recovery is on the rise. Thousands of patients with left-sided heart failure are readily benefitting from these life-saving technologies, and left ventricular failure often leads to severe right ventricular dysfunction or failure. Right ventricular failure (RVF) has a high rate of mortality caused by the risk of multisystem organ failure and prolonged hospitalization for patients after treatment. The use of a blood pump to support the left ventricle also typically results in an increase in right ventricular preload and may impair right ventricular contractility during left ventricular unloading. Patients with RVF might also suffer from severe pulmonary dysfunction, cardiac defects, congenital heart disease states, or a heterogeneity of cardiophysiologic challenges because of symptomatic congestive heart failure. Thus, the uniqueness and complexity of RVF is emerging as a new domain of significant clinical interest that motivates the development of right ventricular assist devices. In this review, we present the current state-of-the-art for clinically used blood pumps to support adults and pediatric patients with right ventricular dysfunction or failure concomitant with left ventricular failure. New innovative devices specifically for RVF are also highlighted. There continues to be a compelling need for novel treatment options to support patients with significant right heart dysfunction or failure.

Enhanced ventricular pump function and decreased reservoir backflow sustain rise in pulmonary blood flow after reduction of lung liquid volume in fetal lambs.

PubMed

Smolich, Joseph J

2014-02-15

Although a reduction in lung liquid volume increases fetal pulmonary blood flow, the changes in central flow patterns that sustain this increased pulmonary perfusion are unknown. To address this issue, eight anesthetized late-gestation fetal sheep were instrumented with pulmonary trunk (PT), ductus arteriosus (DA), and left pulmonary artery (PA) micromanometer catheters and transit-time flow probes, with blood flow profile and wave intensity analyses performed at baseline and after withdrawal of lung liquid via an endotracheal tube. Reducing lung liquid volume by 19 ± 6 ml/kg (mean ± SD) augmented right ventricular power by 34% (P < 0.001), with distribution of an accompanying increase in mean PT blood flow (245 ± 63 ml/min, P < 0.001) to the lungs (169 ± 91 ml/min, P = 0.001) and across the DA (77 ± 92 ml/min, P = 0.04). However, although PT and DA flow increments were confined to systole and were related to an increased magnitude of flow-increasing, forward-running compression waves, the rise in PA flow spanned both systole (108 ± 66 ml/min) and diastole (61 ± 32 ml/min). Flow profile analysis showed that the step-up in PA diastolic flow was associated with diminished PA diastolic backflow and accompanied by a lesser degree of diastolic right-to-left DA shunting. These data suggest that an increased pulmonary blood flow after reduction of lung liquid volume is associated with substantial changes in PT-DA-PA interactions and underpinned by two main factors: 1) enhanced right ventricular pump function that increases PA systolic inflow and 2) decreased PA diastolic backflow that arises from a fundamental change in PA reservoir function, thereby resulting in greater passage of systolic inflow through the lungs.

Assessment of Hydraulic Performance and Biocompatibility of a MagLev Centrifugal Pump System Designed for Pediatric Cardiac or Cardiopulmonary Support

PubMed Central

Dasse, Kurt A.; Gellman, Barry; Kameneva, Marina V.; Woolley, Joshua R.; Johnson, Carl A.; Gempp, Thomas; Marks, John D.; Kent, Stella; Koert, Andrew; Richardson, J. Scott; Franklin, Steve; Snyder, Trevor A.; Wearden, Peter; Wagner, William R.; Gilbert, Richard J.; Borovetz, Harvey S.

2011-01-01

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the Pedi-VAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to ¼ in. For the expected range of pediatric flow (0.3–3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future. PMID:18043164

Effect of milrinone on short term outcome of patients with myocardial dysfunction undergoing off-pump coronary artery bypass graft: a randomized clinical trial.

PubMed

Hadadzadeh, Mehdi; Hosseini, Seyed Habib; Mostafavi Pour Manshadi, Seyed Mohammad Yousof; Naderi, Nafiseh; Emami Meybodi, Mahmood

2013-01-01

Myocardial dysfunction is a major complication in cardiac surgery that needs inotropic support. This study evaluates the effect of milrinone on patients with low ventricular ejection fraction undergoing off- pump coronary artery bypass graft (OPCAB). The present study is designed to evaluate the effect of milrinone on myocardial dysfunction. Eighty patients with low ventricular ejection fraction (<35%), candidate for elective OPCAB, were enrolled in this study. They were randomly assigned to two groups. One group received milrinone (50 μg/kg) intravenously and another group received a saline as placebo followed by 24 hours infusion of each agent (0.5 μg/kg/min). Short outcome of patients such as hemodynamic parameters and left ventricular ejection fraction were variables evaluated. Serum levels of creatine phosphokinase, the MB isoenzyme of creatine kinase, occurrence of arrhythmias and mean duration of mechanical ventilation were significantly lower in milrinone group (P<0.05). The mean post operative left ventricular ejection fraction was significantly higher in milrinone group (P=0.031). There were no statistical significant differences between the two groups in terms of intra-aortic balloon pump, inotropic support requirement, myocardial ischemia, myocardial infarction, duration of inotropic support, duration of intensive care unit stay, mortality and morbidity rate. Administration of milrinone in patients undergoing OPCAB with low ventricular ejection fraction is useful and effective.

Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart.

PubMed

Ott, Harald C; Matthiesen, Thomas S; Goh, Saik-Kia; Black, Lauren D; Kren, Stefan M; Netoff, Theoden I; Taylor, Doris A

2008-02-01

About 3,000 individuals in the United States are awaiting a donor heart; worldwide, 22 million individuals are living with heart failure. A bioartificial heart is a theoretical alternative to transplantation or mechanical left ventricular support. Generating a bioartificial heart requires engineering of cardiac architecture, appropriate cellular constituents and pump function. We decellularized hearts by coronary perfusion with detergents, preserved the underlying extracellular matrix, and produced an acellular, perfusable vascular architecture, competent acellular valves and intact chamber geometry. To mimic cardiac cell composition, we reseeded these constructs with cardiac or endothelial cells. To establish function, we maintained eight constructs for up to 28 d by coronary perfusion in a bioreactor that simulated cardiac physiology. By day 4, we observed macroscopic contractions. By day 8, under physiological load and electrical stimulation, constructs could generate pump function (equivalent to about 2% of adult or 25% of 16-week fetal heart function) in a modified working heart preparation.

Restoration of Pulsatile Flow Reduces Sympathetic Nerve Activity Among Individuals With Continuous-Flow Left Ventricular Assist Devices.

PubMed

Cornwell, William K; Tarumi, Takashi; Stickford, Abigail; Lawley, Justin; Roberts, Monique; Parker, Rosemary; Fitzsimmons, Catherine; Kibe, Julius; Ayers, Colby; Markham, David; Drazner, Mark H; Fu, Qi; Levine, Benjamin D

2015-12-15

Current-generation left ventricular assist devices provide circulatory support that is minimally or entirely nonpulsatile and are associated with marked increases in muscle sympathetic nerve activity (MSNA), likely through a baroreceptor-mediated pathway. We sought to determine whether the restoration of pulsatile flow through modulations in pump speed would reduce MSNA through the arterial baroreceptor reflex. Ten men and 3 women (54 ± 14 years) with Heartmate II continuous-flow left ventricular assist devices underwent hemodynamic and sympathetic neural assessment. Beat-to-beat blood pressure, carotid ultrasonography at the level of the arterial baroreceptors, and MSNA via microneurography were continuously recorded to determine steady-state responses to step changes (200-400 revolutions per minute) in continuous-flow left ventricular assist device pump speed from a maximum of 10,480 ± 315 revolutions per minute to a minimum of 8500 ± 380 revolutions per minute. Reductions in pump speed led to increases in pulse pressure (high versus low speed: 17 ± 7 versus 26 ± 12 mm Hg; P<0.01), distension of the carotid artery, and carotid arterial wall tension (P<0.05 for all measures). In addition, MSNA was reduced (high versus low speed: 41 ± 15 versus 33 ± 16 bursts per minute; P<0.01) despite a reduction in mean arterial pressure and was inversely related to pulse pressure (P=0.037). Among subjects with continuous-flow left ventricular assist devices, the restoration of pulsatile flow through modulations in pump speed leads to increased distortion of the arterial baroreceptors with a subsequent decline in MSNA. Additional study is needed to determine whether reduction of MSNA in this setting leads to improved outcomes. © 2015 American Heart Association, Inc.

Novel maglev pump with a combined magnetic bearing.

PubMed

Onuma, Hiroyuki; Murakami, Michiko; Masuzawa, Toru

2005-01-01

The newly developed pump is a magnetically levitated centrifugal blood pump in which active and passive magnetic bearings are integrated to construct a durable ventricular assist device. The developed maglev centrifugal pump consists of an active magnetic bearing, a passive magnetic bearing, a levitated impeller, and a motor stator. The impeller is set between the active magnetic bearing and the motor stator. The active magnetic bearing uses four electromagnets to control the tilt and the axial position of the impeller. The radial movement of the levitated impeller is restricted with the passive stability dependent upon the top stator and the passive permanent magnetic bearing to reduce the energy consumption and the control system complexity. The top stator was designed based upon a magnetic field analysis to develop the maglev pump with sufficient passive stability in the radial direction. By implementing this analysis design, the oscillating amplitude of the impeller in the radial direction was cut in half when compared with the simple shape stator. This study concluded that the newly developed maglev centrifugal pump displayed excellent levitation performance and sufficient pump performance as a ventricular assist device.

Ventricular assist device

MedlinePlus

... small computer that controls how the pump works. Batteries. The batteries are carried outside your body. They are connected ... to connect the pump to the controller and batteries. The VAD will take blood from your ventricle ( ...

Regional myocardial shape and dimensions of the working isolated canine left ventricle

NASA Technical Reports Server (NTRS)

Ritman, E.; Tsuiki, K.; Donald, D.; Wood, E. H.

1975-01-01

Angiographic experiments were performed on isolated canine left ventricle preparations using donor dog to supply blood to the coronary circulation via a rotary pump to control coronary flow. The angiographic record was transferred from video tape to video disk for detailed uninterrupted sequential analysis at a frequency of 60 fields/sec. It is shown that the use of a biplane X-ray technique and a metabolically supported isolated canine left ventricle preparation provides an angiographically ideal means of measuring the mechanical dynamics of the myocardium while the intact left ventricular myocardial structure and electrical activation pattern retain most of the in situ ventricular characteristics. In particular, biplane X-ray angiography of the left ventricle can provide estimates of total ventricular function such as ejection fraction, stroke volume, and myocardial mass correct to within 15% under the angiographically ideal conditions of the preparation.

Physiological control of a rotary blood pump with selectable therapeutic options: control of pulsatility gradient.

PubMed

Arndt, Andreas; Nüsser, Peter; Graichen, Kurt; Müller, Johannes; Lampe, Bernhard

2008-10-01

A control strategy for rotary blood pumps meeting different user-selectable control objectives is proposed: maximum support with the highest feasible flow rate versus medium support with maximum ventricular washout and controlled opening of the aortic valve (AoV). A pulsatility index (PI) is calculated from the pressure difference, which is deduced from the axial thrust measured by the magnetic bearing of the pump. The gradient of PI with respect to pump speed (GPI) is estimated via online system identification. The outer loop of a cascaded controller regulates GPI to a reference value satisfying the selected control objective. The inner loop controls the PI to a reference value set by the outer loop. Adverse pumping states such as suction and regurgitation can be detected on the basis of the GPI estimates and corrected by the controller. A lumped-parameter computer model of the assisted circulation was used to simulate variations of ventricular contractility, pulmonary venous pressure, and aortic pressure. The performance of the outer control loop was demonstrated by transitions between the two control modes. Fast reaction of the inner loop was tested by stepwise reduction of venous return. For maximum support, a low PI was maintained without inducing ventricular collapse. For maximum washout, the pump worked at a high PI in the transition region between the opening and the permanently closed AoV. The cascaded control of GPI and PI is able to meet different control objectives and is worth testing in vitro and in vivo.

Design, development, and first in vivo results of an implantable ventricular assist device, MicroVad.

PubMed

Kerkhoffs, Wolfgang; Schumacher, Oliver; Meyns, Bart; Verbeken, Erik; Leunens, Veerle; Bollen, Hilde; Reul, Helmut

2004-10-01

The design concept and first in vitro and in vivo results of a long-term implantable ventricular assist device system based on a microaxial blood pump are presented. The blood-immersed parts of the pump consist of a single-stage impeller and a proximally integrated microelectric motor. Both parts are surrounded by a pump housing currently made of polycarbonate to allow visible access to the blood-exposed parts. A titanium inflow cage attached to the tip of the housing is directly implanted into the left ventricular apex. The outflow of the pump is connected to the descending aorta by means of an e-PTFE graft. The overall dimensions of the device are 12 mm in outer diameter and about 50 mm in length. The calculated lifetime of the device is up to 2 years. The system underwent long-term durability tests, hydraulic performance tests, dynamic stability tests, and in vitro hemolysis and thrombogenicity tests. Furthermore, animal tests have been performed in adult Dorset sheep. In a first series, the pump has been placed extracorporeally; in a second series, the pump was completely implanted. Mean duration of the animal experiments of the second series was 31 days (range 8-110 days, n=14); no anticoagulation was administered over the whole test period. Blood data revealed no significant changes in blood cell counts, ionogram, or any other value. No end-organ dysfunction induced by long-term support could be observed, nor did the pathology reveal any evidence of thromboembolic complications.

Continuous-flow cardiac assistance: effects on aortic valve function in a mock loop.

PubMed

Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas

2011-12-01

As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion--with resul-tant aortic regurgitation--has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we tested a continuous-flow LVAD in a mock circulatory system (MCS) with an interposed valve. To mimic the hemodynamic characteristics of LVAD patients, we utilized an MCS in which a Jarvik 2000 LVAD was positioned at the base of a servomotor-operated piston pump (left ventricular chamber). We operated the LVAD at 8000 to 12,000 rpm, changing the speed in 1000-rpm increments. At each speed, we first varied the outflow resistance at a constant stroke volume, then varied the stroke volume at a constant outflow resistance. We measured the left ventricular pressure, aortic pressure, pump flow, and total flow, and used these values to compute the change, if any, in the aortic duty cycle (aortic valve open time) and transvalvular aortic pressure loads. Validation of the MCS was demonstrated by the simulation of physiologic pressure and flow waveforms. At increasing LVAD speeds, the mean aortic pressure load steadily increased, while the aortic duty cycle steadily decreased. Changes were consistent for each MCS experimental setting, despite variations in stroke volume and outflow resistance. Increased LVAD flow results in an impaired aortic valve-open time due to a pressure overload above the aortic valve. Such an overload may initiate structural changes, causing aortic leaflet fusion and/or regurgitation. Copyright © 2011 Elsevier Inc. All rights reserved.

Acute hemodynamic efficacy of a 32-ml subcutaneous counterpulsation device in a calf model of diminished cardiac function.

PubMed

Koenig, Steven C; Litwak, Kenneth N; Giridharan, Guruprasad A; Pantalos, George M; Dowling, Robert D; Prabhu, Sumanth D; Slaughter, Mark S; Sobieski, Michael A; Spence, Paul A

2008-01-01

The acute hemodynamic efficacy of an implantable counterpulsation device (CPD) was evaluated. The CPD is a valveless single port, 32-ml stroke volume blood chamber designed to be connected to the human axillary artery using a simple surface surgical procedure. Blood is drawn into the pump during systole and ejected during diastole. The acute hemodynamic effects of the 32-ml CPD were compared to a standard clinical 40-ml intra-aortic balloon pump (IABP) in calves (80 kg, n = 10). The calves were treated by a single oral dose of Monensin to produce a model of diminished cardiac function (DCF). The CPD and IABP produced similar increases in cardiac output (6% CPD vs. 5% IABP, p > 0.5) and reduction in left ventricular external work (14% CPD vs. 13% IABP, p > 0.5) compared to DCF (p < 0.05). However, the ratio of diastolic coronary artery flow to left ventricular external work increase from DCF baseline (p < 0.05) was greater with the CPD compared to the IABP (15% vs. 4%, p < 0.05). The CPD also produced a greater reduction in left ventricular myocardial oxygen consumption from DCF baseline (p < 0.05) compared to the IABP (13% vs. 9%, p < 0.05) despite each device providing similar improvements in cardiac output. There was no early indication of hemolysis, thrombus formation, or vascular injury. The CPD provides hemodynamic efficacy equivalent to an IABP and may become a therapeutic option for patients who may benefit from prolonged counterpulsation.

Acute Hemodynamic Efficacy of a 32-ml Subcutaneous Counterpulsation Device in a Calf Model of Diminished Cardiac Function

PubMed Central

Koenig, Steven C.; Litwak, Kenneth N.; Giridharan, Guruprasad A.; Pantalos, George M.; Dowling, Robert D.; Prabhu, Sumanth D.; Slaughter, Mark S.; Sobieski, Michael A.; Spence, Paul A.

2010-01-01

The acute hemodynamic efficacy of an implantable counter-pulsation device (CPD) was evaluated. The CPD is a valveless single port, 32-ml stroke volume blood chamber designed to be connected to the human axillary artery using a simple surface surgical procedure. Blood is drawn into the pump during systole and ejected during diastole. The acute hemodynamic effects of the 32-ml CPD were compared to a standard clinical 40-ml intra-aortic balloon pump (IABP) in calves (80 kg, n = 10). The calves were treated by a single oral dose of Monensin to produce a model of diminished cardiac function (DCF). The CPD and IABP produced similar increases in cardiac output (6% CPD vs. 5% IABP, p > 0.5) and reduction in left ventricular external work (14% CPD vs. 13% IABP, p > 0.5) compared to DCF (p < 0.05). However, the ratio of diastolic coronary artery flow to left ventricular external work increase from DCF baseline (p < 0.05) was greater with the CPD compared to the IABP (15% vs. 4%, p < 0.05). The CPD also produced a greater reduction in left ventricular myocardial oxygen consumption from DCF baseline (p < 0.05) compared to the IABP (13% vs. 9%, p < 0.05) despite each device providing similar improvements in cardiac output. There was no early indication of hemolysis, thrombus formation, or vascular injury. The CPD provides hemodynamic efficacy equivalent to an IABP and may become a therapeutic option for patients who may benefit from prolonged counterpulsation. PMID:19033769

Kinematic Characterization of Left Ventricular Chamber Stiffness and Relaxation

NASA Astrophysics Data System (ADS)

Mossahebi, Sina

Heart failure is the most common cause of hospitalization today, and diastolic heart failure accounts for 40-50% of cases. Therefore, it is critical to identify diastolic dysfunction at a subclinical stage so that appropriate therapy can be administered before ventricular function is further, and perhaps irreversibly impaired. Basic concepts in physics such as kinematic modeling provide a unique method with which to characterize cardiovascular physiology, specifically diastolic function (DF). The advantage of an approach that is standard in physics, such as the kinematic modeling is its causal formulation that functions in contrast to correlative approaches traditionally utilized in the life sciences. Our research group has pioneered theoretical and experimental quantitative analysis of DF in humans, using both non-invasive (echocardiography, cardiac MRI) and invasive (simultaneous catheterization-echocardiography) methods. Our group developed and validated the Parametrized Diastolic Filling (PDF) formalism which is motivated by basic physiologic principles (LV is a mechanical suction pump at the mitral valve opening) that obey Newton's Laws. PDF formalism is a kinematic model of filling employing an equation of motion, the solution of which accurately predicts all E-wave contours in accordance with the rules of damped harmonic oscillatory motion. The equation's lumped parameters---ventricular stiffness, ventricular viscoelasticity/relaxation and ventricular load---are obtained by solving the 'inverse problem'. The parameters' physiologic significance and clinical utility have been repeatedly demonstrated in multiple clinical settings. In this work we apply our kinematic modeling approach to better understand how the heart works as it fills in order to advance the relationship between physiology and mathematical modeling. Through the use of this modeling, we thereby define and validate novel, causal indexes of diastolic function such as early rapid filling energy, diastatic stiffness, and relaxation and stiffness components of E-wave deceleration time.

A description of model 3B of the multipurpose ventricular actuating system. [providing controlled driving pressures

NASA Technical Reports Server (NTRS)

Webb, J. A., Jr.

1974-01-01

The multipurpose ventricular actuating system is a pneumatic signal generating device that provides controlled driving pressures for actuating pulsatile blood pumps. Overall system capabilities, the timing circuitry, and calibration instruction are included.

Management of unstable arrhythmias in cardiogenic shock.

PubMed

Saidi, Abdulfattah; Akoum, Nazem; Bader, Feras

2011-08-01

Atrial and ventricular arrhythmias commonly arise in the setting of cardiogenic shock and often result in hemodynamic deterioration. Causative factors include myocardial ischemia, volume overload, and metabolic disturbances. Correcting these factors plays an important role in managing arrhythmias in this setting. Ventricular arrhythmias are more ominous compared to atrial arrhythmias but both require prompt intervention with electrical shock and anti-arrhythmic drug suppression. Coronary reperfusion is key to improving survival, including reducing the risk of sudden cardiac arrest, in acute myocardial infarction. Case series have also demonstrated the value of intra-aortic balloon pump counter-pulsation in suppressing ventricular arrhythmias in cardiogenic shock. The mechanism of arrhythmia suppression may be due to improved coronary perfusion and afterload reduction. Percutaneous ventricular assist device placement may be effective in this setting; however, data addressing this specific endpoint are lacking. Anti-arrhythmic drug options for ventricular and atrial arrhythmia suppression, in the setting of cardiogenic shock, are relatively limited. Common class I agents are excluded due to the inherent abnormal cardiac structure and function in the setting of cardiogenic shock. Class III drug options include dofetilide and amiodarone. The other Class III agents, sotalol and dronedarone, are excluded due to associated mortality observed in the SWORD and ANDROMEDA trials, respectively. Dofetilide is renally excreted and causes QT interval prolongation. Care should be taken to avoid excessive drug accumulation due to poor kidney perfusion and function. Dofetilide is approved for use for atrial arrhythmias and has not been studied for ventricular arrhythmia suppression. The DIAMOND-CHF trial established its safety in the setting of heart failure. Amiodarone is very effective in suppressing both atrial and ventricular arrhythmias. It is often the drug of choice in heart failure. Its off-label use for atrial arrhythmias is very common. Care should be taken with intravenous amiodarone to avoid hypotension.

Exercise reveals impairments in left ventricular systolic function in patients with metabolic syndrome

PubMed Central

Fournier, Sara B.; Reger, Brian L.; Donley, David A.; Bonner, Daniel E.; Warden, Bradford E.; Gharib, Wissam; Failinger, Conard F.; Olfert, Melissa D.; Frisbee, Jefferson C.; Olfert, I. Mark; Chantler, Paul D.

2013-01-01

MetS is the manifestation of a cluster of cardiovascular (CV) risk factors and is associated with a three-fold increase risk of CV morbidity and mortality, which is suggested to be mediated, in part, by resting left ventricular (LV) systolic dysfunction. However, to what extent resting LV systolic function is impaired in MetS is controversial, and there are no data indicating whether LV systolic function is impaired during exercise. Accordingly, the objective of this study was to comprehensively examine LV and arterial responses to exercise in MetS individuals without diabetes and/or overt CVD compared to a healthy control population. CV function was characterized using Doppler echocardiography and gas exchange in MetS (n=27) vs. healthy controls (n=20) at rest and during peak exercise. At rest, MetS individuals displayed normal LV systolic function but reduced LV diastolic function vs. healthy controls. During peak exercise, individuals with MetS had impaired contractility; pump performance, and vasodilator reserve capacity vs. controls. A blunted contractile reserve response resulted in diminished arterial-ventricular coupling reserve and limited aerobic capacity in MetS vs. controls. These findings possess clinical importance as they provide insight to the pathophysiological changes in MetS that may predispose this population of individuals to an increased risk of CV morbidity and mortality. PMID:24036595

Characterization of Regional Left Ventricular Function in Nonhuman Primates Using Magnetic Resonance Imaging Biomarkers: A Test-Retest Repeatability and Inter-Subject Variability Study

PubMed Central

Sampath, Smita; Klimas, Michael; Feng, Dai; Baumgartner, Richard; Manigbas, Elaine; Liang, Ai-Leng; Evelhoch, Jeffrey L.; Chin, Chih-Liang

2015-01-01

Pre-clinical animal models are important to study the fundamental biological and functional mechanisms involved in the longitudinal evolution of heart failure (HF). Particularly, large animal models, like nonhuman primates (NHPs), that possess greater physiological, biochemical, and phylogenetic similarity to humans are gaining interest. To assess the translatability of these models into human diseases, imaging biomarkers play a significant role in non-invasive phenotyping, prediction of downstream remodeling, and evaluation of novel experimental therapeutics. This paper sheds insight into NHP cardiac function through the quantification of magnetic resonance (MR) imaging biomarkers that comprehensively characterize the spatiotemporal dynamics of left ventricular (LV) systolic pumping and LV diastolic relaxation. MR tagging and phase contrast (PC) imaging were used to quantify NHP cardiac strain and flow. Temporal inter-relationships between rotational mechanics, myocardial strain and LV chamber flow are presented, and functional biomarkers are evaluated through test-retest repeatability and inter subject variability analyses. The temporal trends observed in strain and flow was similar to published data in humans. Our results indicate a dominant dimension based pumping during early systole, followed by a torsion dominant pumping action during late systole. Early diastole is characterized by close to 65% of untwist, the remainder of which likely contributes to efficient filling during atrial kick. Our data reveal that moderate to good intra-subject repeatability was observed for peak strain, strain-rates, E/circumferential strain-rate (CSR) ratio, E/longitudinal strain-rate (LSR) ratio, and deceleration time. The inter-subject variability was high for strain dyssynchrony, diastolic strain-rates, peak torsion and peak untwist rate. We have successfully characterized cardiac function in NHPs using MR imaging. Peak strain, average systolic strain-rate, diastolic E/CSR and E/LSR ratios, and deceleration time were identified as robust biomarkers that could potentially be applied to future pre-clinical drug studies. PMID:26010607

An ultimate, compact, seal-less centrifugal ventricular assist device: Baylor C-Gyro pump.

PubMed

Ohara, Y; Makinouchi, K; Orime, Y; Tasai, K; Naito, K; Mizuguchi, K; Shimono, T; Damm, G; Glueck, J; Takatani, S

1994-01-01

We have developed a compact, seal-less, all-purpose centrifugal pump, the Baylor C-Gyro pump, which is intended as a long-term ventricular assist device (VAD) as well as a cardiopulmonary bypass pump. In attaining this goal, we began with eliminating the shaft seals by adopting a pivot bearing system at the impeller shaft. In addition, a ring magnet encased in the bottom of the impeller was coupled magnetically to a driver magnet placed outside the pump housing (C1 Prototype). This first model yielded satisfactory performance in vitro with a flow rate of 8 L/min against 250 mm Hg at 2,400 rpm, and an index of hemolysis (IH) of 0.0083 g/100 L using bovine blood. In the second model, the C1 Eccentric Inlet Port Model, the inlet bearing support bar in the prototype were eliminated without reducing the prototype's performance. These designs for antithrombogenicity are being tested by the first in vivo experiment, which has lasted for more than 2 weeks.

Performance characterization of a rotary centrifugal left ventricular assist device with magnetic suspension.

PubMed

Jahanmir, Said; Hunsberger, Andrew Z; Heshmat, Hooshang; Tomaszewski, Michael J; Walton, James F; Weiss, William J; Lukic, Branka; Pae, William E; Zapanta, Conrad M; Khalapyan, Tigran Z

2008-05-01

The MiTiHeart (MiTiHeart Corporation, Gaithersburg, MD, USA) left ventricular assist device (LVAD), a third-generation blood pump, is being developed for destination therapy for adult heart failure patients of small to medium frame that are not being served by present pulsatile devices. The pump design is based on a novel, patented, hybrid passive/active magnetic bearing system with backup hydrodynamic thrust bearing and exhibits low power loss, low vibration, and low hemolysis. Performance of the titanium alloy prototype was evaluated in a series of in vitro tests with blood analogue to map out the performance envelop of the pump. The LVAD prototype was implanted in a calf animal model, and the in vivo pump performance was evaluated. The animal's native heart imparted a strong pulsatility to the flow rate. These tests confirmed the efficacy of the MiTiHeart LVAD design and confirmed that the pulsatility does not adversely affect the pump performance.

Posterior papillary muscle anchoring affects remote myofiber stress and pump function: finite element analysis.

PubMed

Pantoja, Joe Luis; Ge, Liang; Zhang, Zhihong; Morrel, William G; Guccione, Julius M; Grossi, Eugene A; Ratcliffe, Mark B

2014-10-01

The role of posterior papillary muscle anchoring (PPMA) in the management of chronic ischemic mitral regurgitation (CIMR) is controversial. We studied the effect of anchoring point direction and relocation displacement on left ventricular (LV) regional myofiber stress and pump function. Previously described finite element models of sheep 16 weeks after posterolateral myocardial infarction (MI) were used. True-sized mitral annuloplasty (MA) ring insertion plus different PPM anchoring techniques were simulated. Anchoring points tested included both commissures and the central anterior mitral annulus; relocation displacement varied from 10% to 40% of baseline diastolic distance from the PPM to the anchor points on the annulus. For each reconstruction scenario, myofiber stress in the MI, border zone, and remote myocardium as well as pump function were calculated. PPMA caused reductions in myofiber stress at end-diastole and end-systole in all regions of the left ventricle that were proportional to the relocation displacement. Although stress reduction was greatest in the MI region, it also occurred in the remote region. The maximum 40% displacement caused a slight reduction in LV pump function. However, with the correction of regurgitation by MA plus PPMA, there was an overall increase in forward stroke volume. Finally, anchoring point direction had no effect on myofiber stress or pump function. PPMA reduces remote myofiber stress, which is proportional to the absolute distance of relocation and independent of anchoring point. Aggressive use of PPMA techniques to reduce remote myofiber stress may accelerate reverse LV remodeling without impairing LV function. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

In reply to: "Intra-aortic balloon pump protects against hydrostatic pulmonary oedema during peripheral venoarterial-extracorporeal membrane oxygenation".

PubMed

Privratsky, Jamie R; Diaz, Sebastian; Nicoara, Alina; Daneshmand, Mani A

2018-05-01

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an increasingly utilized life-saving measure. However, left-ventricular distention from inadequate left-ventricular off-loading can lead to unwanted pulmonary and cardiac complications. We are writing to indicate our agreement with a recent article by Brechot et al. published in the June 2017 issue where the authors demonstrated that intra-aortic balloon pump provides mechanical support to off-load the left ventricle during VA-ECMO, which prevents pulmonary edema.

[Coronary revascularization in patients with preoperative electrical storm].

PubMed

Kawashima, Toshiya; Naraoka, S

2007-03-01

We report 5 cases who underwent surgical coronary revascularization for subacute myocardial ischemia with preoperative electrical storm. All patients showed severe left ventricular dysfunction. Mean ejection fraction was 24.4 +/- 7.6%. Three patients had already had implantable cardioverter-defibrillator (ICD) therapy. Procedures were on-pump coronary artery bypass grafting (CABG) and mitral valvuloplasty (MVP) [case 1], on-pump CABG, MVP, left ventricular restoration (LVR) and cryoablation (case 2), and off-pump CABG (case 3-5). Case 5 necessitated conversion to on-pump for electrical storm during left circumflex artery (LCx) anastomosis. Case 3 suddenly died on the 2nd postoperative day due to electrical storm. Case 1 had recurrent attack of electrical storm postoperatively, treated by ICD, overdrive pacing, repeated intraaortic balloon pumping (IABP), deep sedation with endotracheal intubation, and finally catheter ablation. Four patients have survived 2 years (mean) postoperatively without any arrhythmia, and are all in good condition [New York Heart Association (NYHA) I] now. It was concluded that off-pump procedure was not suitable for subacute myocardial ischemia with electrical storm and that LVR with surgical cryoablation would be effective if indicated.

Ten years single-centre experience with intra-aortic balloon pump.

PubMed

Vandenplas, Guy; Bové, Thierry; Caes, Frank; Van Belleghem, Yves; François, Katrien; De Somer, Filip; Taeymans, Yves; Van Nooten, Guido

2011-12-01

The objective of this study was to investigate the patient characteristics and outcomes in 1406 patients undergoing intra-aortic balloon pump (IABP) counterpulsation. Between 1998 and 2008, 1406 consecutive patients were recorded in a prospective database. Based on the main clinical indication for IABP use, we defined 3 groups: group A, 630 cases of coronary ischaemia or infarction without serious left ventricular (LV) dysfunction; group B, 466 patients with left ventricular failure or cardiogenic shock; group C, 310 patients where IABP was used for miscellaneous procedures such as weaning from cardiopulmonary bypass or during high-risk angioplasty or surgery. Global mortality was 28% (n = 390), with a significant difference between group A (15%, n = 95) and group B (41%, n = 191) (P < 0.001). Mortality in group C was 34% (n = 104). Most insertions were done in the catheterization laboratory (n = 943) with subsequent mortality of 23% whereas 199 balloons were inserted in the operation room with 34% mortality. 170 balloons inserted in the intensive care unit resulted in 46% mortality (P < 0.001). Major IABP-induced complications were 6.8% with no statistical differences between the three groups. Advanced age, left ventricular failure and low BMI were identified as prognostic risk factors for early mortality. IABP deployed at an early clinical stage yields the best results, especially for acute coronary patients with preserved LV function whereas LV failure and late insertion result in worse outcome.

Computational fluid dynamics analysis of a maglev centrifugal left ventricular assist device.

PubMed

Burgreen, Greg W; Loree, Howard M; Bourque, Kevin; Dague, Charles; Poirier, Victor L; Farrar, David; Hampton, Edward; Wu, Z Jon; Gempp, Thomas M; Schöb, Reto

2004-10-01

The fluid dynamics of the Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA, U.S.A.) left ventricular assist device are analyzed over a range of physiological operating conditions. The HeartMate III is a centrifugal flow pump with a magnetically suspended rotor. The complete pump was analyzed using computational fluid dynamics (CFD) analysis and experimental particle imaging flow visualization (PIFV). A comparison of CFD predictions to experimental imaging shows good agreement. Both CFD and experimental PIFV confirmed well-behaved flow fields in the main components of the HeartMate III pump: inlet, volute, and outlet. The HeartMate III is shown to exhibit clean flow features and good surface washing across its entire operating range.

Evaluation of left ventricular assist device pump bladders cast from ion-sputtered polytetrafluorethylene mandrels

NASA Technical Reports Server (NTRS)

1982-01-01

A highly thromboresistant blood contacting interface for use in implanatable blood pump is investigated. Biomaterials mechanics, dynamics, durability, surface morphology, and chemistry are among the critical consideration pertinent to the choice of an appropriate blood pump bladder material. The use of transfer cast biopolymers from ion beam textured surfaces is investigated to detect subtle variations in blood pump surface morphology using Biomer as the biomaterial of choice. The efficacy of ion beam sputtering as an acceptable method of fabricating textured blood interfaces is evaluated. Aortic grafts and left ventricular assist devices were implanted in claves; the blood interfaces were fabricated by transfer casting methods from ion beam textured polytetrafluorethylene mandrels. The mandrels were textured by superimposing a 15 micron screen mesh; ion sputtering conditions were 300 volts beam energy, 40 to 50 mA beam, and a mandrel to source distance of 25 microns.

Left atrial physiology and pathophysiology: Role of deformation imaging

PubMed Central

Kowallick, Johannes Tammo; Lotz, Joachim; Hasenfuß, Gerd; Schuster, Andreas

2015-01-01

The left atrium (LA) acts as a modulator of left ventricular (LV) filling. Although there is considerable evidence to support the use of LA maximum and minimum volumes for disease prediction, theoretical considerations and a growing body of literature suggest to focus on the quantification of the three basic LA functions: (1) Reservoir function: collection of pulmonary venous return during LV systole; (2) Conduit function: passage of blood to the left ventricle during early LV diastole; and (3) Contractile booster pump function (augmentation of ventricular filling during late LV diastole. Tremendous advances in our ability to non-invasively characterize all three elements of atrial function include speckle tracking echocardiography (STE), and more recently cardiovascular magnetic resonance myocardial feature tracking (CMR-FT). Corresponding imaging biomarkers are increasingly recognized to have incremental roles in determining prognosis and risk stratification in cardiac dysfunction of different origins. The current editorial introduces the role of STE and CMR-FT for the functional assessment of LA deformation as determined by strain and strain rate imaging and provides an outlook of how this exciting field may develop in the future. PMID:26131333

The effect of acute mechanical left ventricular unloading on ovine tricuspid annular size and geometry.

PubMed

Malinowski, Marcin; Wilton, Penny; Khaghani, Asghar; Brown, Michael; Langholz, David; Hooker, Victoria; Eberhart, Lenora; Hooker, Robert L; Timek, Tomasz A

2016-09-01

Left ventricular assist device (LVAD) implantation may alter right ventricular shape and function and lead to tricuspid regurgitation. This in turn has been reported to be a determinant of right ventricular (RV) failure after LVAD implantation, but the effect of mechanical left ventricular (LV) unloading on the tricuspid annulus is unknown. The aim of the study was to provide insight into the effect of LVAD support on tricuspid annular geometry and dynamics that may help to optimize LV unloading with the least deleterious effect on the right-sided geometry. In seven open-chest anaesthetized sheep, nine sonomicrometry crystals were implanted on the right ventricle. Additional nine crystals were implanted around the tricuspid annulus, with one crystal at each commissure defining three separate annular regions: anterior, posterior and septal. Left ventricular unloading was achieved by connecting a cannula in the left atrium and the aorta to a continuous-flow pump. The pump was used for 15 min at a full flow of 3.8 ± 0.3 l/min. Epicardial echocardiography was used to assess the degree of tricuspid insufficiency. Haemodynamic, echocardiographic and sonomicrometry data were collected before and during full unloading. Tricuspid annular area, and the regional and total perimeter were calculated from crystal coordinates, while 3D annular geometry was expressed as the orthogonal distance of each annular crystal to the least squares plane of all annular crystals. There was no significant tricuspid regurgitation observed either before or during LV unloading. Right ventricular free wall to septum diameter increased significantly at end-diastole during unloading from 23.6 ± 5.8 to 26.3 ± 6.5 mm (P = 0.009), but the right ventricular volume, tricuspid annular area and total perimeter did not change from baseline. However, the septal part of the annulus significantly decreased its maximal length (38.6 ± 8.1 to 37.9 ± 8.2 mm, P = 0.03). Annular contraction was not altered. The tricuspid annulus had a complex 3D saddle-shaped geometry that was unaffected during experimental conditions. In healthy sheep hearts, left ventricular unloading increased septal-free wall RV diameter and reduced the length of the septal annulus, without altering the motion or geometry of the tricuspid annulus. Acute left ventricular unloading alone in healthy sheep was not sufficient to significantly perturb tricuspid annular dynamics and result in tricuspid insufficiency. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Late outcomes of subcostal exchange of the HeartMate II left ventricular assist device: a word of caution.

PubMed

Yu, Sarah N; Takayama, Hiroo; Han, Jiho; Garan, Arthur R; Kurlansky, Paul; Yuzefpolskaya, Melana; Colombo, Paolo C; Naka, Yoshifumi; Takeda, Koji

2018-04-10

Previous studies have shown the usefulness of the subcostal exchange of the HeartMate II left ventricular assist device for device malfunction. However, long-term data are still limited. Between March 2004 and July 2017, 41 of 568 (7.2%) patients who had received a HeartMate II implant at our institution had a device exchange via a subcostal incision. We summarized early and late outcomes. Forty-one patients had a total of 48 subcostal pump exchanges. Indications for device exchange included device thrombosis (n = 31, 76%), driveline infection (n = 2, 5%) and driveline injury (n = 8, 19%). All of the procedures were successful, and there were no in-hospital deaths. A Kaplan-Meier survival curve showed 30-day and 1-year survival rates after subcostal exchange of 100% and 94.6%, respectively. However, 10 (25%) patients had left ventricular assist device-related infections following subcostal exchange that included 7 pump pocket infections and 3 driveline infections. Freedom from left ventricular assist device-related infection at 1 year after subcostal exchange was 79.3%. Thirteen (32%) patients had device malfunction due to pump thrombosis that required a 2nd device exchange. Seven patients had recurrent thrombosis. Three (7%) patients had a stroke. Freedom from device thrombosis and from a stroke event at 1 year was 74.4%. Subcostal pump exchange can be safely performed. However, there is a substantial risk of infection and recurrent thrombosis. Careful follow-up for late complications is mandatory.

Impact of Residual Mitral Regurgitation on Right Ventricular Systolic Function After Left Ventricular Assist Device Implantation.

PubMed

Ertugay, Serkan; Kemal, Hatice S; Kahraman, Umit; Engin, Catagay; Nalbantgil, Sanem; Yagdi, Tahir; Ozbaran, Mustafa

2017-07-01

Significant mitral regurgitation (MR) is thought to decrease after left ventricular assist device (LVAD) implantation, and therefore repair of mitral valve is not indicated in current practice. However, residual moderate and severe MR leads to pulmonary artery pressure increase, thereby resulting in right ventricular (RV) dysfunction during follow-up. We examined the impact of residual MR on systolic function of the right ventricle by echocardiography after LVAD implantation. This study included 90 patients (mean age: 51.7 ± 10.9 years, 14.4% female) who underwent LVAD implantation (HeartMate II = 21, HeartWare = 69) in a single center between December 2010 and June 2014. Echocardiograms obtained at 3-6 months and over after implantation were analyzed retrospectively. RV systolic function was graded as normal, mild, moderate, and severely depressed. MR (≥moderate) was observed in 43 and 44% of patients at early and late period, respectively. Systolic function of the RV was severely depressed in 16 and 9% of all patients. Initial analysis (mean duration of support 174.3 ± 42.5 days) showed a statistically significant correlation between less MR and improved systolic function of RV (P = 0.01). Secondary echocardiographic analysis (following a mean duration of support of 435.1 ± 203 days) was also statistically significant for MR degree and RV systolic dysfunction (P = 0.008). Residual MR after LVAD implantation may cause deterioration of RV systolic function and cause right-sided heart failure symptoms. Repair of severe MR, in selected patients such as those with severe pulmonary hypertension and depressed RV, may be considered to improve the patient's clinical course during pump support. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Preconditions for constructing a biomechanical model of the heart as an integral musculovascular organ

NASA Astrophysics Data System (ADS)

Edemskii, M. L.; Kogan, V. A.

1981-07-01

Relative to its major function, pumping, the heart should be considered as an integral musculovascular organ. It is precisely this integration in the structural and functional sense which permits the heart not only to perform its pump function as a converter of chemical energy supplied by the blood into mechanical flow energy but also to combine the supply and conversion of energy into a single cycle, produce the hydrodynamics of cardiac output in definite fashion, and introduce a correction into the filling phase according to current arterial pressure as the most dynamic index of systemic hemodynamics. The breakdown of the structure of the cardiac pump into elements differing in their functional significance permits us to delineate at least three channels for the utilization of energy supplied to the heart and consumed in the major pumping function: the mechanical work performed by the lower part of the cardiac muscle that is displaced into the ventricular space, the energy consumed on maintaining the systolic pressure of the myocardial fibers which form the relatively immobile upper and side walls of the heart, and the energy consumed on maintaining the high tone of the muscular walls of the coronary arteries and arterioles which form the hydraulic frame of the heart. A representation of the heart which includes muscular and vascular components, in our view, is the basic prerequisite for the development of mathematical models for the cardiac pump based on energy balance equations and suitable for solving the problems posed by clinical medicine in regard to auxiliary blood circulation.

Feasibility of a tiny Gyro centrifugal pump as an implantable ventricular assist device.

PubMed

Yoshikawa, M; Nakata, K; Ohtsuka, G; Takano, T; Glueck, J; Fujisawa, A; Makinouchi, K; Yokokawa, M; Nosé, Y

1999-08-01

The Gyro pumps were developed for long-term circulatory support. The first generation Gyro pump (C1E3) achieved 1 month paracorporeal circulatory support in chronic animal experiments; the second generation (PI702) implantable ventricular assist device (VAD) was successful for over 6 months. The objective of the next generation Gyro pump is for use as a long-term totally implantable VAD and for pediatric circulatory support. This tiny Gyro pump (KP101) was fabricated with the same design concept as the other Gyro pumps. The possibility of an implantable VAD was determined after performance and hemolysis test results were compared to those of the other Gyro pumps. The pump housing and impeller were fabricated from polycarbonate with an impeller diameter of 35 mm. The diameter and height of the pump housings are 52.3 mm and 29.9 mm, respectively. At this time, a DC brushless motor drives the KP101, which is the same as that for the C1E3. The pump performance was measured in 37% glycerin water at 37 degrees C. Hemolysis tests were performed utilizing a compact mock loop filled with fresh bovine blood in a left ventricular assist device (LVAD) condition at 37 degrees C. The KP101 achieved the LVAD conditions of 5 L/min and 100 mm Hg at 2,900 rpm; generated 10 L/min against 100 mm Hg at 3,200 rpm; 3 L/min against 90 mm Hg at 2,600 rpm; and 2 L/min against 80 mm Hg at 2,400 rpm. In addition, the pump efficiency during this experiment was 12.5%. The other Gyro pumps. that is, the C1E3, PI601, and PI701, in an LVAD condition require 1,600, 2,000, and 2,000 rpm, respectively. The KP101 produced a normalized index of hemolysis (NIH) value of 0.005 g/100 L. With regard to the NIH, the other Gyro pumps, namely the C1E3, PI601, and PI701 demonstrated 0.0007, 0.0028, and 0.004 g/100 L, respectively. The KP101 produced an acceptable pressure flow curve for a VAD. The NIH value was higher than that of other Gyro pumps, but is in an acceptable range.

Ventriculostomy Simulation Using Patient-Specific Ventricular Anatomy, 3D Printing, and Hydrogel Casting.

PubMed

Ryan, Justin R; Chen, Tsinsue; Nakaji, Peter; Frakes, David H; Gonzalez, L Fernando

2015-11-01

Educational simulators provide a means for students and experts to learn and refine surgical skills. Educators can leverage the strengths of medical simulators to effectively teach complex and high-risk surgical procedures, such as placement of an external ventricular drain. Our objective was to develop a cost-effective, patient-derived medical simulacrum for cerebral lateral ventriculostomy. A cost-effective, patient-derived medical simulacrum was developed for placement of an external lateral ventriculostomy. Elastomeric and gel casting techniques were used to achieve realistic brain geometry and material properties. 3D printing technology was leveraged to develop accurate cranial properties and dimensions. An economical, gravity-driven pump was developed to provide normal and abnormal ventricular pressures. A small pilot study was performed to gauge simulation efficacy using a technology acceptance model. An accurate geometric representation of the brain was developed with independent lateral cerebral ventricular chambers. A gravity-driven pump pressurized the ventricular cavities to physiologic values. A qualitative study illustrated that the simulation has potential as an educational tool to train medical professionals in the ventriculostomy procedure. The ventricular simulacrum can improve learning in a medical education environment. Rapid prototyping and multi-material casting techniques can produce patient-derived models for cost-effective and realistic surgical training scenarios. Copyright © 2015 Elsevier Inc. All rights reserved.

Ventricular fibrillation in an ambulatory patient supported by a left ventricular assist device: highlighting the ICD controversy.

PubMed

Boilson, Barry A; Durham, Lucian A; Park, Soon J

2012-01-01

Left ventricular assist devices (LVADs) provide an effective means of managing advanced pump failure as a means of bridging to cardiac transplantation or as permanent therapy. Although ventricular arrhythmias remain common post-LVAD implantation, such therapy may allow malignant arrhythmias to be tolerated hemodynamically. This report describes the clinical findings in a patient who had likely been in a ventricular tachyarrhythmia for several days and presented in ventricular fibrillation, ambulatory, and mentating normally. This report, with previous similar reports, is additive to the body of evidence that LVADs alter the physiologic impact of ventricular arrhythmias in advanced heart failure and highlights the need for thoughtful programming of implantable cardioverter defibrillator therapies in these patients.

Anisotropic Reinforcement of Acute Anteroapical Infarcts Improves Pump Function

PubMed Central

Fomovsky, Gregory M.; Clark, Samantha A.; Parker, Katherine M.; Ailawadi, Gorav; Holmes, Jeffrey W.

2012-01-01

Background We hypothesize that a therapy that improves LV pump function early after infarction should decrease the need for compensation through sympathetic activation and dilation, thereby reducing the risk of developing heart failure. The mechanical properties of healing myocardial infarcts are an important determinant of left ventricular (LV) function, yet improving function by altering infarct properties has proven unexpectedly difficult. Using a computational model, we recently predicted that stiffening a large anterior infarct anisotropically (in only one direction) would improve LV function, while isotropic stiffening, the focus of previous studies and therapies, would not. The goal of this study was to test the novel strategy of anisotropic infarct reinforcement. Methods and Results We tested the effects of anisotropic infarct reinforcement in 10 open-chest dogs with large anteroapical infarcts that depressed LV pump function. We measured regional mechanics, LV volumes, and cardiac output at a range of preloads at Baseline, 45 minutes after coronary ligation (Ischemia), and 30 minutes later, following surgical reinforcement in the longitudinal direction (Anisotropic). Ischemia shifted the end-systolic pressure-volume relationship (ESPVR) and cardiac output curves rightward, decreasing cardiac output at matched end-diastolic pressure (EDP) by 44%. Anisotropic reinforcement significantly improved systolic function without impairing diastolic function, recovering half the deficit in overall LV function. Conclusions We conclude that anisotropic reinforcement is a promising new approach to improving LV function following a large myocardial infarction. PMID:22665716

Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

PubMed

Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

2016-03-01

Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

Hybrid model analysis of intra-aortic balloon pump performance as a function of ventricular and circulatory parameters.

PubMed

Ferrari, Gianfranco; Khir, Ashraf W; Fresiello, Libera; Di Molfetta, Arianna; Kozarski, Maciej

2011-09-01

We investigated the effects of the intra-aortic balloon pump (IABP) on endocardial viability ratio (EVR), cardiac output (CO), end-systolic (V(es)) and end-diastolic (V(ed)) ventricular volumes, total coronary blood flow (TCBF), and ventricular energetics (external work [EW], pressure-volume area [PVA]) under different ventricular (E(max) and diastolic stiffness) and circulatory (arterial compliance) parameters. We derived a hybrid model from a computational model, which is based on merging computational and hydraulic submodels. The lumped parameter computational submodel consists of left and right hearts and systemic, pulmonary, and coronary circulations. The hydraulic submodel includes part of the systemic arterial circulation, essentially a silicone rubber tube representing the aorta, which contains a 40-mL IAB. EVR, CO, V(es), and V(ed), TCBF and ventricular energetics (EW, PVA) were analyzed against the ranges of left ventricular E(max) (0.3-0.5-1 mm Hg/cm(3)) and diastolic stiffness V(stiffness) (≈0.08 and ≈0.3 mm Hg/cm(3), obtained by changing diastolic stiffness constant) and systemic arterial compliance (1.8-2.5 cm(3)/mm Hg). All experiments were performed comparing the selected variables before and during IABP assistance. Increasing E(maxl) from 0.5 to 2 mm Hg/cm(3) resulted in IABP assistance producing lower percentage changes in the selected variables. The changes in ventricular diastolic stiffness strongly influence both absolute value of EVR and its variations during IABP (71 and 65% for lower and higher arterial compliance, respectively). V(ed) and V(es) changes are rather small but higher for lower E(max) and higher V(stiffness). Lower E(max) and higher V(stiffness) resulted in higher TCBF and CO during IABP assistance (∼35 and 10%, respectively). The use of this hybrid model allows for testing real devices in realistic, stable, and repeatable circulatory conditions. Specifically, the presented results show that IABP performance is dependent, at least in part, on left ventricular filling, ejection characteristics, and arterial compliance. It is possible in this way to simulate patient-specific conditions and predict the IABP performance at different values of the circulatory or ventricular parameters. Further work is required to study the conditions for heart recovery modeling, baroreceptor controls, and physiological feedbacks. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Myocardial mechanics, energetics, and hemodynamics during intraaortic balloon and transvalvular axial flow hemopump support with a bovine model of ischemic cardiac dysfunction.

PubMed

Marks, J D; Pantalos, G M; Long, J W; Kinoshita, M; Everett, S D; Olsen, D B

1999-01-01

Unlike the mechanisms of intraaortic balloon pump (IABP) support, the mechanisms by which transvalvular axial flow Hemopump (HP) support benefit dysfunctional myocardium are less clearly understood. To help elucidate these mechanisms, hemodynamic, metabolic, and mechanical indexes of left ventricular function were measured during conditions of control, ischemic dysfunction, IABP support, and HP support. A large animal (calf) model of left ventricular dysfunction was created with multiple coronary ligations. Peak intraventricular pressure increased with HP support and decreased with IABP support. Intramyocardial pressure (an indicator of intramyocardial stress), time rate of pressure change (an indicator of contractility), and left ventricular myocardial oxygen consumption decreased with IABP and HP support. Left ventricular work decreased with HP support and increased with IABP support. During HP support, indexes of wall stress, work, and contractility, all primary determinants of oxygen consumption, were reduced. During IABP support, indexes of wall stress and contractility were reduced and external work increased. These changes were attributed primarily to changes in ventricular preload, and geometry for HP support, and to a reduction in afterload for IABP support. These findings support the hypothesis that both HP and IABP support reduce intramyocardial stress development and the corresponding oxygen consumption, although via different mechanisms.

Intra-aortic balloon pump combined with mechanical ventilation for treating patients aged > 60 years in cardiogenic shock: Retrospective analysis

PubMed Central

Liu, Hongwei; Wu, Xueping; Zhao, Xiaoning; Zhu, Ping

2016-01-01

Objective To examine if mechanical ventilation with positive end-expiratory pressure (PEEP) combined with intra-aortic balloon pump (IABP) provided a better outcome than IABP alone for the treatment of cardiogenic shock after acute myocardial infarction in patients aged > 60 years. Methods This was a retrospective analysis of data from patients in cardiogenic shock, refractory to pharmacological therapy and treated at a geriatric coronary care unit. Results Sixty-two patients were eligible for study inclusion: 33 received IABP alone; 29 received IABP combined with mechanical ventilation. Patients in the IABP + mechanical ventilation group had lower mean arterial blood pressure (BP), systolic BP and partial pressure of oxygen compared with the IABP group, indicating worse cardiac and pulmonary function. In addition, higher rates of pulmonary infection and renal insufficiency were observed in the IABP + mechanical ventilation group than in the IABP group. A statistically significant improvement of left ventricular function before and after treatment was observed in the IABP + mechanical ventilation group, but not in the IABP group. Pulmonary infection and renal insufficiency were risk factors for all-cause in-hospital mortality; successful revascularization was a negative risk factor. There was no between-group difference in survival. Conclusion Mechanical ventilation with an appropriate level of PEEP appears to enhance the beneficial effects of IABP on left ventricular function for patients in cardiogenic shock. PMID:27020597

In Vivo Evaluation of Active and Passive Physiological Control Systems for Rotary Left and Right Ventricular Assist Devices.

PubMed

Gregory, Shaun D; Stevens, Michael C; Pauls, Jo P; Schummy, Emma; Diab, Sara; Thomson, Bruce; Anderson, Ben; Tansley, Geoff; Salamonsen, Robert; Fraser, John F; Timms, Daniel

2016-09-01

Preventing ventricular suction and venous congestion through balancing flow rates and circulatory volumes with dual rotary ventricular assist devices (VADs) configured for biventricular support is clinically challenging due to their low preload and high afterload sensitivities relative to the natural heart. This study presents the in vivo evaluation of several physiological control systems, which aim to prevent ventricular suction and venous congestion. The control systems included a sensor-based, master/slave (MS) controller that altered left and right VAD speed based on pressure and flow; a sensor-less compliant inflow cannula (IC), which altered inlet resistance and, therefore, pump flow based on preload; a sensor-less compliant outflow cannula (OC) on the right VAD, which altered outlet resistance and thus pump flow based on afterload; and a combined controller, which incorporated the MS controller, compliant IC, and compliant OC. Each control system was evaluated in vivo under step increases in systemic (SVR ∼1400-2400 dyne/s/cm(5) ) and pulmonary (PVR ∼200-1000 dyne/s/cm(5) ) vascular resistances in four sheep supported by dual rotary VADs in a biventricular assist configuration. Constant speed support was also evaluated for comparison and resulted in suction events during all resistance increases and pulmonary congestion during SVR increases. The MS controller reduced suction events and prevented congestion through an initial sharp reduction in pump flow followed by a gradual return to baseline (5.0 L/min). The compliant IC prevented suction events; however, reduced pump flows and pulmonary congestion were noted during the SVR increase. The compliant OC maintained pump flow close to baseline (5.0 L/min) and prevented suction and congestion during PVR increases. The combined controller responded similarly to the MS controller to prevent suction and congestion events in all cases while providing a backup system in the event of single controller failure. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Chronic animal experiment with magnetically suspended centrifugal pump.

PubMed

Yamada, T; Nishimura, K; Park, C H; Kono, S; Yuasa, S; Tsukiya, T; Akamatsu, T; Matsuda, K; Ban, T

1997-07-01

We have been developing a new type of centrifugal pump for long-term use. The magnetically suspended centrifugal pump (MSCP) contains no shaft and seal so that long life expectancy is predicted. Paracorporeal left ventricular (LV) assist circulation between the left atrium and the descending aorta was instituted using sheep. The flow rates ranged from 2.5-5.5 L/min. The sheep that lived the longest (46 days) died of an embolism as a result of the thrombus in the pump. No thrombus formation was observed in other pumps. Plasma free hemoglobin levels ranged from 9 to 18 mg/dl, which led to the conclusion that the hemolysis level remained within an acceptable range. Two driving modes were compared. The slope of the pressure-flow relationship plot under a constant motor current mode was steeper than that under a constant rotational speed mode, and thus, the flow fluctuation decreased. In conclusion, the MSCP is durable for more than a month at the current stage of development and is a promising device for long-term ventricular assist.

Evaluation of platelet aggregability during left ventricular bypass using a MedTech MagLev VAD in a series of chronic calf experiments.

PubMed

Kimura, Taro; Yokoyama, Yoshimasa; Sakota, Daisuke; Nagaoka, Eiki; Kitao, Takashi; Takakuda, Kazuo; Takatani, Setsuo

2013-03-01

The impact of continuous flow left ventricular assist device (LVAD) pumping on platelet aggregation was investigated in animal experiments utilizing six calves. A single-use MagLev centrifugal blood pump, MedTech MagLev, was used to bypass the calves' hearts from the left atrium to the descending aorta at a flow rate of 50 ml/kg/min. The LVAD's impact on blood coagulation activities was evaluated based on the platelet aggregability, which was measured with a turbidimetric assay method during the preoperative, operative, and postoperative periods. Heparin and warfarin were used for anticoagulation, while aspirin was used for the antiplatelet therapy. A decrease in platelet aggregation immediately after the pump started was observed in the cases of successful long-term pump operation, while the absence of such a decrease might have caused coagulation-related complications to terminate the experiments. Thus, the platelet aggregability was found to be significantly affected by the pump, and its initial trend may be related to the long-term outcome of the mechanical circulatory support.

Prediction of the external work of the native heart from the dynamic H-Q curves of the rotary blood pumps during left heart bypass.

PubMed

Yokoyama, Yoshimasa; Kawaguchi, Osamu; Kitao, Takashi; Kimura, Taro; Steinseifer, Ulrich; Takatani, Setsuo

2010-09-01

The ventricular performance is dependent on the drainage effect of rotary blood pumps (RBPs) and the performance of RBPs is affected by the ventricular pulsation. In this study, the interaction between the ventricle and RBPs was examined using the pressure-volume (P-V) diagram of the ventricle and dynamic head pressure-bypass flow (H-Q) curves (H, head pressure: arterial pressure minus ventricular pressure vs. Q, bypass flow) of the RBPs. We first investigated the relationships in a mock loop with a passive fill ventricle, followed by validation in ex vivo animal experiments. An apical drainage cannula with a micro-pressure sensor was especially fabricated to obtain ventricular pressure, while three pairs of ultrasonic crystals placed on the heart wall were used to derive ventricular volume. The mock loop-configured ventricular apical-descending aorta bypass revealed that the external work of the ventricle expressed by the area inside the P-V diagrams (EW(Heart) ) correlated strongly with the area inside dynamic H-Q curves (EW(VAD)), with the coefficients of correlation being R² = 0.869 ∼ 0.961. The results in the mock loop were verified in the ex vivo studies using three Shiba goats (10-25 kg in body weight), showing the correlation coefficients of R² = 0.802 ∼ 0.817. The linear regression analysis indicated that the increase in the bypass flow reduced pulsatility in the ventricle expressed in EW(Heart) as well as in EW(VAD) . Experimental results, both mock loop and animal studies, showed that the interaction between cardiac external work and H-Q performance of RBPs can be expressed by the relationships "EW(Heart) versus EW(VAD) ." The pulsatile nature of the native heart can be expressed in the area underneath the H-Q curves of RBPs EW(VAD) during left heart bypass indicating the status of the level of assistance by RBPs and the native heart function. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Exercise reveals impairments in left ventricular systolic function in patients with metabolic syndrome.

PubMed

Fournier, Sara B; Reger, Brian L; Donley, David A; Bonner, Daniel E; Warden, Bradford E; Gharib, Wissam; Failinger, Conard F; Olfert, Melissa D; Frisbee, Jefferson C; Olfert, I Mark; Chantler, Paul D

2014-01-01

Metabolic syndrome (MetS) is the manifestation of a cluster of cardiovascular risk factors and is associated with a threefold increase in the risk of cardiovascular morbidity and mortality, which is suggested to be mediated, in part, by resting left ventricular (LV) systolic dysfunction. However, to what extent resting LV systolic function is impaired in MetS is controversial, and there are no data indicating whether LV systolic function is impaired during exercise. Accordingly, the objective of this study was to examine comprehensively the LV and arterial responses to exercise in individuals with MetS without diabetes and/or overt cardiovascular disease in comparison to a healthy control population. Cardiovascular function was characterized using Doppler echocardiography and gas exchange in individuals with MetS (n = 27) versus healthy control subjects (n = 20) at rest and during peak exercise. At rest, individuals with MetS displayed normal LV systolic function but reduced LV diastolic function compared with healthy control subjects. During peak exercise, individuals with MetS had impaired contractility, pump performance and vasodilator reserve capacity versus control subjects. A blunted contractile reserve response resulted in diminished arterial-ventricular coupling reserve and limited aerobic capacity in individuals with MetS versus control subjects. These findings are of clinical importance, because they provide insight into the pathophysiological changes in MetS that may predispose this population of individuals to an increased risk of cardiovascular morbidity and mortality.

Development of a prototype magnetically suspended rotor ventricular assist device.

PubMed

Bearnson, G B; Maslen, E H; Olsen, D B; Allaire, P E; Khanwilkar, P S; Long, J W; Kim, H C

1996-01-01

A continuous flow centrifugal blood pump with magnetically suspended impeller has been designed, constructed, and tested. The system can be functionally divided into three subsystem designs: 1) centrifugal pump and flow paths, 2) magnetic bearings, and 3) brushless DC motor. The centrifugal pump is a Francis vane type design with a designed operating point of 6 L/min flow and 100 mmHg pressure rise at 2,300 RPM. Peak hydraulic efficiency is over 50%. The magnetic bearing system is an all active design with five axes of control. Rotor position sensors were developed as part of the system to provide feedback to a proportional-integral-derivative controller. The motor is a sensorless brushless DC motor. Back electromotive force voltage generated by the motor is used to provide commutation for the motor. No slots are employed in the motor design in order to reduce the radial force that the bearings must generate. Tests pumping blood in vitro were very encouraging; an index of hemolysis of 0.0086 +/- 0.0012 was measured. Further design refinement is needed to reduce power dissipation and size of the device. The concept of using magnetic bearings in a blood pump shows promise in a long-term implantable blood pump.

Total vascular resistance and blood flow frequency during left ventricular assistance using a vibrating flow pump.

PubMed

Kobayashi, S; Owada, N; Yambe, T; Nitta, S; Fukuju, T; Hongoh, T; Hashimoto, H

1999-08-01

A vibrating flow pump (VFP) can generate high frequency oscillated blood flow within 10-30 Hz by the oscillation of its central tube. A totally implantable artificial heart using a VFP is being developed as a unique type of blood pump. In this study, left ventricular (LV) assist circulation was performed using a VFP. The total vascular resistance and driving frequency of the VFP were estimated from their relationship. The effect of oscillation on the vascular system was studied by the frequency analysis method and vascular impedance. Adult goats were anesthetized by halothane using an inhaler and a left fourth thoracotomy was performed. The inflow cannula was inserted into the left ventricle, and the outflow cannula was sutured to the descending aorta. The VFP and a centrifugal pump were set in parallel for alternation and comparison. The driving frequency of the VFP was changed and included 15, 20, 25, and 30 Hz. The hemodynamic parameters were continuously recorded during experiments by a digital audio tape (DAT) data recorder. The internal pressure of the left ventricular cavity and aortic pressure were monitored by the pressure manometers continuously. One hundred percent LV assistance was judged by the separation of LV and aortic pressure. The total vascular resistance was decreased by the start of operation of each pump. The decrease during flow using the VFP was not as large as that using a centrifugal pump (CP). The arterial input impedance during oscillated blood flow by the VFP showed a slow curve appearance. It was similar to the frequency characteristics curve of natural heart beats within the lower frequencies. The study of arterial impedance may be important for the estimation of the reflection of the pulsatile wave from the arterial branch, among other things.

New concepts and new design of permanent maglev rotary artificial heart blood pumps.

PubMed

Qian, K X; Zeng, P; Ru, W M; Yuan, H Y

2006-05-01

According to tradition, permanent maglev cannot achieve stable equilibrium. The authors have developed, to the contrary, two stable permanent maglev impeller blood pumps. The first pump is an axially driven uni-ventricular assist pump, in which the rotor with impeller is radially supported by two passive magnetic bearings, but has one point contact with the stator axially at standstill. As the pump raises its rotating speed, the increasing hydrodynamic force of fluid acting on the impeller will make the rotor taking off from contacting point and disaffiliate from the stator. Then the rotor becomes fully suspended. The second pump is a radially driven bi-ventricular assist pump, i.e., an impeller total artificial heart. Its rotor with two impellers on both ends is supported by two passive magnetic bearings, which counteract the attractive force between rotor magnets and stator coil iron core. The rotor is affiliated to the stator radially at standstill and becomes levitated during rotation. Therefore, the rotor keeps concentric with stator during rotation but eccentric at standstill, as is confirmed by rotor position detection with Honeywell sensors. It concludes that the permanent maglev needs action of a non-magnetic force to achieve stability but a rotating magnetic levitator with high speed and large inertia can maintain its stability merely with passive magnetic bearings.

Does off-pump coronary surgery reduce morbidity and mortality?

PubMed

Sabik, Joseph F; Gillinov, A Marc; Blackstone, Eugene H; Vacha, Catherine; Houghtaling, Penny L; Navia, Jose; Smedira, Nicholas G; McCarthy, Patrick M; Cosgrove, Delos M; Lytle, Bruce W

2002-10-01

To compare hospital outcomes of on-pump and off-pump coronary artery bypass surgery. From 1997 to 2000, primary coronary artery bypass grafting was performed in 481 patients off pump and in 3231 patients on pump. Hospital outcomes were compared between propensity-matched pairs of 406 on-pump and 406 off-pump patients. The 2 groups were similar in age (P =.9), left ventricular function (P =.7), extent of coronary artery disease (P =.5), carotid artery disease (P =.4), and chronic obstructive pulmonary disease (P =.5). However, off-pump patients had more previous strokes (P =.05) and peripheral vascular disease (P =.02); on-pump patients had a higher preoperative New York Heart Association class (P =.01). In the matched pairs the mean number of bypass grafts was 2.8 +/- 1.0 in off-pump patients and 3.5 +/- 1.1 in on-pump patients (P <.001). Fewer grafts were performed to the circumflex (P <.001) and right coronary (P =.006) artery systems in the off-pump patients. Postoperative mortality, stroke, myocardial infarction, and reoperation for bleeding were similar in the 2 groups. There was more encephalopathy (P =.02), sternal wound infection (P =.04), red blood cell use (P =.002), and renal failure requiring dialysis (P =.03) in the on-pump patients. Both off- and on-pump procedures produced excellent early clinical results with low mortality. An advantage of an off-pump operation was less postoperative morbidity; however, less complete revascularization introduced uncertainty about late results. A disadvantage of on-pump bypass was higher morbidity that seemed attributable to cardiopulmonary bypass.

Developments in control systems for rotary left ventricular assist devices for heart failure patients: a review.

PubMed

AlOmari, Abdul-Hakeem H; Savkin, Andrey V; Stevens, Michael; Mason, David G; Timms, Daniel L; Salamonsen, Robert F; Lovell, Nigel H

2013-01-01

From the moment of creation to the moment of death, the heart works tirelessly to circulate blood, being a critical organ to sustain life. As a non-stopping pumping machine, it operates continuously to pump blood through our bodies to supply all cells with oxygen and necessary nutrients. When the heart fails, the supplement of blood to the body's organs to meet metabolic demands will deteriorate. The treatment of the participating causes is the ideal approach to treat heart failure (HF). As this often cannot be done effectively, the medical management of HF is a difficult challenge. Implantable rotary blood pumps (IRBPs) have the potential to become a viable long-term treatment option for bridging to heart transplantation or destination therapy. This increases the potential for the patients to leave the hospital and resume normal lives. Control of IRBPs is one of the most important design goals in providing long-term alternative treatment for HF patients. Over the years, many control algorithms including invasive and non-invasive techniques have been developed in the hope of physiologically and adaptively controlling left ventricular assist devices and thus avoiding such undesired pumping states as left ventricular collapse caused by suction. In this paper, we aim to provide a comprehensive review of the developments of control systems and techniques that have been applied to control IRBPs.

Experimental Assessment of the Hydraulics of a Miniature Axial-Flow Left Ventricular Assist Device

NASA Astrophysics Data System (ADS)

Smith, P. Alex; Cohn, William; Metcalfe, Ralph

2017-11-01

A minimally invasive partial-support left ventricular assist device (LVAD) has been proposed with a flow path from the left atrium to the arterial system to reduce left ventricular stroke work. In LVAD design, peak and average efficiency must be balanced over the operating range to reduce blood trauma. Axial flow pumps have many geometric parameters. Until recently, testing all these parameters was impractical, but modern 3D printing technology enables multi-parameter studies. Following theoretical design, experimental hydraulic evaluation in steady state conditions examines pressure, flow, pressure-flow gradient, efficiency, torque, and axial force as output parameters. Preliminary results suggest that impeller blades and stator vanes with higher inlet angles than recommended by mean line theory (MLT) produce flatter gradients and broader efficiency curves, increasing compatibility with heart physiology. These blades also produce less axial force, which reduces bearing load. However, they require slightly higher torque, which is more demanding of the motor. MLT is a low order, empirical model developed on large pumps. It does not account for the significant viscous losses in small pumps like LVADs. This emphasizes the importance of experimental testing for hydraulic design. Roderick D MacDonald Research Fund.

Design and evaluation of a single-pivot supported centrifugal blood pump.

PubMed

Yoshino, M; Uemura, M; Takahashi, K; Watanabe, N; Hoshi, H; Ohuchi, K; Nakamura, M; Fujita, H; Sakamoto, T; Takatani, S

2001-09-01

In order to develop a centrifugal blood pump that meets the requirements of a long-term, implantable circulatory support device, in this study a single-pivot bearing supported centrifugal blood pump was designed to evaluate its basic performance. The single-pivot structure consisted of a ceramic ball male pivot mounted on the bottom surface of the impeller and a polyethylene female pivot incorporated in the bottom pump casing. The follower magnet mounted inside the impeller was magnetically coupled to the driver magnet mounted on the shaft of the direct current brushless motor. As the motor rotated, the impeller rotated supported entirely by a single-pivot bearing system. The static pump performance obtained in the mock circulatory loop revealed an acceptable performance as a left ventricular assist device in terms of flow and head pressure. The pump flow of 5 L/min against the head pressure of 100 mm Hg was obtained at rotational speeds of 2,000 to 2,200 rpm. The maximum pump flow was 9 L/min with 2,200 rpm. The maximum electrical-to-hydraulic power conversion efficiency was around 14% at pump flows of 4 to 5 L/min. The stability of the impeller was demonstrated at the pump rpm higher than 1,400 with a single-pivot bearing without an additional support at its top. The single-pivot supported centrifugal pump can provide adequate flow and pressure as a ventricular assist device, but its mechanical stability and hemolytic as well as thrombotic performances must be tested prior to clinical use.

The MicroMed DeBakey VAD

NASA Image and Video Library

2004-06-23

JSC2004-E-26519 --- Dr. Michael DeBakey (far right) observes preparation procedures before the implantation of a MicroMed DeBakey VAD® (ventricular assist device). The revolutionary heart pump received FDA approval in February 2004 for use in critically ill children awaiting heart transplants. The heart pump was designed with the help of NASA engineers who began working with Dr. DeBakey on the pump's development in the mid-1980s.

EVAHEART: an implantable centrifugal blood pump for long-term circulatory support.

PubMed

Yamazaki, Kenji; Kihara, Shinichiro; Akimoto, Takehide; Tagusari, Osamu; Kawai, Akihiko; Umezu, Mitsuo; Tomioka, Jun; Kormos, Robert L; Griffith, Bartley P; Kurosawa, Hiromi

2002-11-01

We developed "EVAHEART": a compact centrifugal blood pump system as an implantable left ventricular assist device for long-term circulatory support. The 55 x 64 mm pump is made from pure titanium, and weighs 370 g. The entire blood-contacting surface is covered with an anti-thrombogenic coating of diamond like carbon (DLC) or 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve blood compatibility. Flows exceeding 12 L/min against 100 mmHg pressure at 2600 rpm was measured. A low-temperature mechanical seal with recirculating cooling system is used to seal the shaft. EVAHEART demonstrated an acceptably low hemolysis rate with normalized index of hemolysis of 0.005 +/- 0.002 g/100L. We evaluated the pump in long-term in-vivo experiments with seven calves. Via left thoracotomy, we conducted left ventricular apex-descending aorta bypass, placing the pump in the left thoracic cavity. Pump flow rates was maintained at 5-9 L/min, pump power consumption remained stable at 9-10 W in all cases, plasma free Hb levels were less than 15 mg/dl, and the seal system showed good seal capability throughout the experiments. The calves were sacrificed on schedule on postoperative day 200, 222, 142, 90, 151, 155, and 133. No thrombi formed on the blood contacting surface with either the DLC or MPC coating, and no major organ thromboembolisms occurred except for a few small renal infarcts. EVAHEART centrifugal blood pump demonstrated excellent performance in long-term in-vivo experiments.

Assessment of Safety and Effectiveness of the Extracorporeal Continuous-Flow Ventricular Assist Device (BR16010) Use as a Bridge-to-Decision Therapy for Severe Heart Failure or Refractory Cardiogenic Shock: Study Protocol for Single-Arm Non-randomized, Uncontrolled, and Investigator-Initiated Clinical Trial.

PubMed

Fukushima, Norihide; Tatsumi, Eisuke; Seguchi, Osamu; Takewa, Yoshiaki; Hamasaki, Toshimitsu; Onda, Kaori; Yamamoto, Haruko; Hayashi, Teruyuki; Fujita, Tomoyuki; Kobayashi, Junjiro

2018-06-08

The management of heart failure patients presenting in a moribund state remains challenging, despite significant advances in the field of ventricular assist systems. Bridge to decision involves using temporary devices to stabilize the hemodynamic state of such patients while further assessment is performed and a decision can be made regarding patient management. The purpose of this study (NCVC-BTD_01, National Cerebral and Cardiovascular Center-Bridge to Dicision_01) is to assess the safety and effectiveness of the newly developed extracorporeal continuous-flow ventricular assist system employing a disposable centrifugal pump with a hydrodynamically levitated bearing (BR16010) use as a bridge-to-decision therapy for patients with severe heart failure or refractory cardiogenic shock. NCVC-BTD_01 is a single-center, single-arm, open-label, exploratory, medical device, investigator-initiated clinical study. It is conducted at the National Cerebral and Cardiovascular Center in Japan. A total of nine patients will be enrolled in the study. The study was planned using Simon's minimax two-stage phase design. The primary endpoint is a composite of survival free of device-related serious adverse events and complications during device support. For left ventricular assistance, withdrawal of a trial device due to cardiac function recovery or exchange to other ventricular assist devices (VADs) for the purpose of bridge to transplantation (BTT) during 30 days after implantation will be considered study successes. For right ventricular assistance, withdrawal of tal device due to right ventricular function recovery within 30 days after implantation will be considered a study success. Secondary objectives include changes in brain natriuretic peptide levels (7 days after implantation of a trial device and the day of withdrawal of a trial device), period of mechanical ventricular support, changes in left ventricular ejection fraction (7 days after implantation of a trial device and the day of withdrawal of a trial device), and changes in left ventricular diastolic dimension (7 days after implantation of a trial device and the day of withdrawal of a trial device). We will disseminate the findings through regional, national, and international conferences and through peer-reviewed journals. UMIN Clinical Trials Registry (UMIN-CTR; R000033243) registered on 8 September 2017.

Hydrodynamic endurance test of the prosthetic valve used in the various types of the ventricular assist device.

PubMed

Nitta, S; Yambe, T; Katahira, Y; Sonobe, T; Saijoh, Y; Naganuma, S; Akiho, H; Kakinuma, Y; Tanaka, M; Miura, M

1991-12-01

To evaluate the various basic designs of the pump chambers used in the ventricular assist devices (VADs), hydrodynamic endurance test was performed from the viewpoint of the durability of the prosthetic valves used in the VAD. For the hydrodynamic analysis, we designed three basic types of pump (sac type, diaphragm type, and pusher plate type) using the same material and having the same capacity and shape. Prosthetic valves in these VADs were tested from the standpoint of the water hammer effect, which affects the valve durability, to determine which pump design would be most durable as a prosthetic valve in the VAD. The water-hammer phenomenon was evaluated using the maximum pressure gradient (MPG) across the prosthetic valve in the moc circulatory loop. Maximum pump output was recorded when we used the diaphragm type model, and minimum MPG in the commonly used driving condition of the VAD were recorded when we used the sac type model. The results suggest that the sac type VAD model is the most durable design for the prosthetic value.

Development and evaluation of totally implantable ventricular assist system using a vibrating flow pump and transcutaneous energy transmission system with amorphous fibers.

PubMed

Yambe, T; Hashimoto, H; Kobayashi, S; Sonobe, T; Naganuma, S; Nanka, S S; Matsuki, H; Yoshizawa, M; Tabayashi, K; Takayasu, H; Takeda, H; Nitta, S

1997-01-01

We have developed a vibrating flow pump (VFP) that can generate oscillated blood flow with a relatively high frequency (10-50 Hz) for a totally implantable ventricular assist system (VAS). To evaluate the newly developed VAS, left heart bypasses, using the VFP, were performed in chronic animal experiments. Hemodynamic parameters were recorded in a data recorder in healthy adult goats during an awake condition and analyzed in a personal computer system through an alternating-direct current converter. Basic performance of the total system with a transcutaneous energy transmission system were satisfactory. During left ventricular assistance with the VFP, Mayer wave fluctuations of hemodynamics were decreased in the power spectrum, the fractal dimensions of the hemodynamics were significantly decreased, and peripheral vascular resistance was significantly decreased. These results suggest that cardiovascular regulatory nonlinear dynamics, which mediate the hemodynamics, may be affected by left ventricular bypass with oscillated flow. The decreased power of the Mayer wave in the spectrum caused the limit cycle attractor of the hemodynamics and decreased peripheral resistance. These results suggest that this newly developed VAS is useful for the totally implantable system with unique characteristics that can control hemodynamic properties.

Body position and activity, but not heart rate, affect pump flows in patients with continuous-flow left ventricular assist devices.

PubMed

Muthiah, Kavitha; Gupta, Sunil; Otton, James; Robson, Desiree; Walker, Robyn; Tay, Andre; Macdonald, Peter; Keogh, Anne; Kotlyar, Eugene; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

2014-08-01

The aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). Although it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. Two studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. Heart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. Centrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Closing the gap in paediatric ventricular assist device therapy with the Berlin Heart EXCOR® 15-ml pump.

PubMed

De Rita, Fabrizio; Griselli, Massimo; Sandica, Eugen; Miera, Oliver; Karimova, Ann; d'Udekem, Yves; Goldwasser, Ranny; Januszewska, Katarzyna; Amodeo, Antonio; Jurrmann, Nadine; Ersel, Simon; Menon, Ares K

2017-05-01

The Berlin Heart EXCOR ® (EXCOR) paediatric ventricular assist device is used worldwide for mechanical support of infants and small children with end-stage heart failure. A clinically important gap between the smallest EXCOR blood pump (10 ml) and the next larger size (25 ml) limited the choice of pump size in patients with a body surface area (BSA) between 0.33 and 0.5 m 2 . We present the first clinical experience from the early product surveillance (EPS) of the new EXCOR 15-ml blood pump. After CE and U.S. Food and Drug Administration approval in January 2013, 20 patients with a mean age of 1.6 years (range 0.5-3.5 years) and a mean BSA of 0.45 m 2 (range 0.33-0.59 m 2 ) were enrolled in the EPS. The main diagnosis was idiopathic cardiomyopathy in 13 patients; the majority ( n =  16) of children were in INTERMACS level 1 or 2. Data from high-volume paediatric transplant centres were collected prospectively for a defined follow-up period of 60 days after device implantation. Mean time on the EXCOR 15-ml blood pump was 43 days; the survival rate was 100% at the end of the EPS period. Seven patients underwent a heart transplant from the device; 2 children were weaned; and 11 patients remained on support. Infection of cannula exit sites occurred in 3 patients. Two patients had minor thromboembolic strokes but made a complete neurological recovery. The new EXCOR 15-ml blood pump demonstrated optimal ventricular assist device support of children with a BSA of 0.33-0.5 m 2 . © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Computational prediction of the effects of the intra-aortic balloon pump on heart failure with valvular regurgitation using a 3D cardiac electromechanical model.

PubMed

Kim, Chang-Hyun; Song, Kwang-Soup; Trayanova, Natalia A; Lim, Ki Moo

2018-05-01

Intra-aortic balloon pump (IABP) is normally contraindicated in significant aortic regurgitation (AR). It causes and aggravates pre-existing AR while performing well in the event of mitral regurgitation (MR). Indirect parameters, such as the mean systolic pressure, product of heart rate and peak systolic pressure, and pressure-volume are used to quantify the effect of IABP on ventricular workload. However, to date, no studies have directly quantified the reduction in workload with IABP. The goal of this study is to examine the effect of IABP therapy on ventricular mechanics under valvular insufficiency by using a computational model of the heart. For this purpose, the 3D electromechanical model of the failing ventricles used in previous studies was coupled with a lumped parameter model of valvular regurgitation and the IABP-treated vascular system. The IABP therapy was disturbed in terms of reducing the myocardial tension generation and contractile ATP consumption by valvular regurgitation, particularly in the AR condition. The IABP worsened the problem of ventricular expansion induced as a result of the regurgitated blood volume during the diastole under the AR condition. The IABP reduced the LV stroke work in the AR, MR, and no regurgitation conditions. Therefore, the IABP helped the ventricle to pump blood and reduced the ventricular workload. In conclusion, the IABP partially performed its role in the MR condition. However, it was disturbed by the AR and worsened the cardiovascular responses that followed the AR. Therefore, this study computationally proved the reason for the clinical contraindication of IABP in AR patients.

A servo-controlled canine model of stable severe ischemic left ventricular failure.

PubMed

Wagner, Richard L; Hood, William B; Howland, Peter A

2009-12-01

Reversible left ventricular failure was produced in conscious dogs by compromise of the coronary circulation. In animals with prior left anterior descending coronary artery occlusion, mean left atrial pressure (LAP) was incorporated into an automatic feedback control system used to inflate a balloon cuff on the circumflex (Cfx) coronary artery. The system could produce stable increases in LAP to 15-20 mm Hg. The dominating system transfer function was the ratio of LAP to balloon volume (BV), which was characterized by a fixed delay (5 s), with LAP/BV = (8e(-jomegatau ))/(0.02 + jomega). The system was stabilized by a phase lead network to reduce oscillations of LAP. A total of seven experiments were conducted in three dogs, and testing of inotropic agents was possible in three experiments under stable conditions with the pump off after an hour or more of operation. Problems encountered were 0.003-0.008 Hz oscillations in LAP in three experiments, which could usually be controlled by reducing the system gain. Late stage ventricular fibrillation occurred in all three animals, but defibrillation was easily accomplished after deflating the Cfx balloon. This system produces reversible left ventricular failure solely due to ischemia, thus closely simulating clinical heart failure due to coronary insufficiency.

Thermal Analysis of the PediaFlow pediatric ventricular assist device.

PubMed

Gardiner, Jeffrey M; Wu, Jingchun; Noh, Myounggyu D; Antaki, James F; Snyder, Trevor A; Paden, David B; Paden, Brad E

2007-01-01

Accurate modeling of heat dissipation in pediatric intracorporeal devices is crucial in avoiding tissue and blood thermotrauma. Thermal models of new Maglev ventricular assist device (VAD) concepts for the PediaFlow VAD are developed by incorporating empirical heat transfer equations with thermal finite element analysis (FEA). The models assume three main sources of waste heat generation: copper motor windings, active magnetic thrust bearing windings, and eddy currents generated within the titanium housing due to the two-pole motor. Waste heat leaves the pump by convection into blood passing through the pump and conduction through surrounding tissue. Coefficients of convection are calculated and assigned locally along fluid path surfaces of the three-dimensional pump housing model. FEA thermal analysis yields a three-dimensional temperature distribution for each of the three candidate pump models. Thermal impedances from the motor and thrust bearing windings to tissue and blood contacting surfaces are estimated based on maximum temperature rise at respective surfaces. A new updated model for the chosen pump topology is created incorporating computational fluid dynamics with empirical fluid and heat transfer equations. This model represents the final geometry of the first generation prototype, incorporates eddy current heating, and has 60 discrete convection regions. Thermal analysis is performed at nominal and maximum flow rates, and temperature distributions are plotted. Results suggest that the pump will not exceed a temperature rise of 2 degrees C during normal operation.

Design of a miniature implantable left ventricular assist device using CAD/CAM technology.

PubMed

Okamoto, Eiji; Hashimoto, Takuya; Mitamura, Yoshinori

2003-01-01

In this study, we developed a new miniature motor-driven pulsatile left ventricular assist device (LVAD) for implantation into a Japanese patient of average build by means of computer-aided design and manufacturing (CAD/CAM) technology. A specially designed miniature ball-screw and a high-performance brushless DC motor were used in an artificial heart actuator to allow miniaturization. A blood pump chamber (stroke volume 55 ml) and an inflow and outflow port were designed by computational fluid dynamics (CFD) analysis. The geometry of the blood pump was evaluated using the value of index of pump geometry (IPG) = (Reynolds shear stress) x (occupied volume) as a quantitative index for optimization. The calculated value of IPG varied from 20.6 Nm to 49.1 Nm, depending on small variations in pump geometry. We determined the optimum pump geometry based on the results of quantitative evaluation using IPG and qualitative evaluation using the flow velocity distribution with blood flow tracking. The geometry of the blood pump that gave lower shear stress had more optimum spiral flow around the diaphragm-housing (D-H) junction. The volume and weight of the new LVAD, made of epoxy resin, is 309 ml and 378 g, but further miniaturization will be possible by improving the geometry of both the blood pump and the back casing. Our results show that our new design method for an implantable LVAD using CAD/CAM promises to improve blood compatibility with greater miniaturization.

Sarcomeric protein modification during adrenergic stress enhances cross-bridge kinetics and cardiac output

PubMed Central

Gresham, Kenneth S.; Mamidi, Ranganath; Li, Jiayang; Kwak, Hyerin

2017-01-01

Molecular adaptations to chronic neurohormonal stress, including sarcomeric protein cleavage and phosphorylation, provide a mechanism to increase ventricular contractility and enhance cardiac output, yet the link between sarcomeric protein modifications and changes in myocardial function remains unclear. To examine the effects of neurohormonal stress on posttranslational modifications of sarcomeric proteins, mice were administered combined α- and β-adrenergic receptor agonists (isoproterenol and phenylephrine, IPE) for 14 days using implantable osmotic pumps. In addition to significant cardiac hypertrophy and increased maximal ventricular pressure, IPE treatment accelerated pressure development and relaxation (74% increase in dP/dtmax and 14% decrease in τ), resulting in a 52% increase in cardiac output compared with saline (SAL)-treated mice. Accelerated pressure development was maintained when accounting for changes in heart rate and preload, suggesting that myocardial adaptations contribute to enhanced ventricular contractility. Ventricular myocardium isolated from IPE-treated mice displayed a significant reduction in troponin I (TnI) and myosin-binding protein C (MyBP-C) expression and a concomitant increase in the phosphorylation levels of the remaining TnI and MyBP-C protein compared with myocardium isolated from saline-treated control mice. Skinned myocardium isolated from IPE-treated mice displayed a significant acceleration in the rate of cross-bridge (XB) detachment (46% increase) and an enhanced magnitude of XB recruitment (43% increase) at submaximal Ca2+ activation compared with SAL-treated mice but unaltered myofilament Ca2+ sensitivity of force generation. These findings demonstrate that sarcomeric protein modifications during neurohormonal stress are molecular adaptations that enhance in vivo ventricular contractility through accelerated XB kinetics to increase cardiac output. NEW & NOTEWORTHY Posttranslational modifications to sarcomeric regulatory proteins provide a mechanism to modulate cardiac function in response to stress. In this study, we demonstrate that neurohormonal stress produces modifications to myosin-binding protein C and troponin I, including a reduction in protein expression within the sarcomere and increased phosphorylation of the remaining protein, which serve to enhance cross-bridge kinetics and increase cardiac output. These findings highlight the importance of sarcomeric regulatory protein modifications in modulating ventricular function during cardiac stress. PMID:27909224

Sarcomeric protein modification during adrenergic stress enhances cross-bridge kinetics and cardiac output.

PubMed

Gresham, Kenneth S; Mamidi, Ranganath; Li, Jiayang; Kwak, Hyerin; Stelzer, Julian E

2017-03-01

Molecular adaptations to chronic neurohormonal stress, including sarcomeric protein cleavage and phosphorylation, provide a mechanism to increase ventricular contractility and enhance cardiac output, yet the link between sarcomeric protein modifications and changes in myocardial function remains unclear. To examine the effects of neurohormonal stress on posttranslational modifications of sarcomeric proteins, mice were administered combined α- and β-adrenergic receptor agonists (isoproterenol and phenylephrine, IPE) for 14 days using implantable osmotic pumps. In addition to significant cardiac hypertrophy and increased maximal ventricular pressure, IPE treatment accelerated pressure development and relaxation (74% increase in dP/d t max and 14% decrease in τ), resulting in a 52% increase in cardiac output compared with saline (SAL)-treated mice. Accelerated pressure development was maintained when accounting for changes in heart rate and preload, suggesting that myocardial adaptations contribute to enhanced ventricular contractility. Ventricular myocardium isolated from IPE-treated mice displayed a significant reduction in troponin I (TnI) and myosin-binding protein C (MyBP-C) expression and a concomitant increase in the phosphorylation levels of the remaining TnI and MyBP-C protein compared with myocardium isolated from saline-treated control mice. Skinned myocardium isolated from IPE-treated mice displayed a significant acceleration in the rate of cross-bridge (XB) detachment (46% increase) and an enhanced magnitude of XB recruitment (43% increase) at submaximal Ca 2+ activation compared with SAL-treated mice but unaltered myofilament Ca 2+ sensitivity of force generation. These findings demonstrate that sarcomeric protein modifications during neurohormonal stress are molecular adaptations that enhance in vivo ventricular contractility through accelerated XB kinetics to increase cardiac output. NEW & NOTEWORTHY Posttranslational modifications to sarcomeric regulatory proteins provide a mechanism to modulate cardiac function in response to stress. In this study, we demonstrate that neurohormonal stress produces modifications to myosin-binding protein C and troponin I, including a reduction in protein expression within the sarcomere and increased phosphorylation of the remaining protein, which serve to enhance cross-bridge kinetics and increase cardiac output. These findings highlight the importance of sarcomeric regulatory protein modifications in modulating ventricular function during cardiac stress. Copyright © 2017 the American Physiological Society.

Use of cardiopulmonary pump support during coronary artery bypass grafting in the high-risk: a meta-analysis.

PubMed

Yousif, A; Addison, D; Lakkis, N; Rosengart, T; Virani, S S; Birnbaum, Y; Alam, M

2018-05-01

Data from randomized trials evaluating the efficacy of on- versus off-pump coronary artery bypass grafting remain inconclusive, particularly in high-risk populations. The aim of this study is to compare the outcomes associated with on- versus off-pump coronary artery bypass grafting among high-risk patients. We performed a meta-analysis of randomized control trials comparing on- versus off-pump coronary artery bypass grafting, focusing on high-risk populations. Studies focusing on "high-risk" features: European System of Cardiac Operative Risk Evaluation (EuroSCORE) ≥ 5, age > 70 years, preexisting renal insufficiency, history of stroke(s), and the presence of left ventricular dysfunction were included. MEDLINE, Scopus, and Embase were searched for all publications between January 1, 2000 and August 1, 2016, using the following terms: on-pump, off-pump, coronary artery bypass, high-risk, left ventricular dysfunction, elderly, aged, and renal insufficiency. Endpoints included cardiovascular and all-cause mortality, non-fatal myocardial infarction, stroke, need for revascularization, renal failure, and length of hospital stay. Nine studies incorporating 11,374 patients with a mean age of 70 years were selected. There was no statistical difference in cardiovascular mortality, all-cause mortality, non-fatal myocardial infarction, and renal failure between the two groups. There was a decrease in further revascularization at 1 year with on-pump (OR 0.67 (0.50-0.89)). However, there was an increase in length of hospital stay by 2.24 days (p = 0.03) among the on-pump group with no difference in stroke (OR 1.34 (1.00-1.80)). On-pump is associated with a decreased risk of additional revascularization by 1 year. However, this appears to be a cost of longer hospitalization.

Right ventricular dyssynchrony in idiopathic pulmonary arterial hypertension: determinants and impact on pump function.

PubMed

Badagliacca, Roberto; Poscia, Roberto; Pezzuto, Beatrice; Papa, Silvia; Gambardella, Cristina; Francone, Marco; Mezzapesa, Mario; Nocioni, Martina; Nona, Alfred; Rosati, Riccardo; Sciomer, Susanna; Fedele, Francesco; Dario Vizza, Carmine

2015-03-01

Right ventricular (RV) dyssynchrony has been described in pulmonary arterial hypertension (PAH), but no evidence is available on its morphologic determinants and its effect on systolic function. The aim of this study was to evaluate the morphologic determinants of RV dyssynchrony by echocardiographic and cardiac magnetic resonance imaging and its effect on systolic function. In 60 consecutive idiopathic PAH (IPAH) patients with narrow QRS, RV dyssynchrony was evaluated by 2D speckle-tracking echocardiography, calculating the standard deviation of the times to peak systolic strain for the four mid-basal RV segments (RV-SD4). Patients were grouped by the median value of RV-SD4 (19 milliseconds) and compared for RV remodeling and systolic function parameters, WHO class, pulmonary hemodynamics and 6-minute walk test (6MWT). Despite similar pulmonary vascular resistance and mean pulmonary arterial pressure, patients with RV-SD4 at >19 milliseconds had advanced WHO class and worse 6MWT, RV hemodynamics, RV remodeling and systolic function parameters compared with patients at ≤19 milliseconds. The morphologic determinants of RV dyssynchrony resulted RV end-diastolic area, LV diastolic eccentricity index and RV mass volume ratio (r = 0.69, r(2) = 0.47, p < 0.0001). Finally, we found a significant inverse correlation between RV mid-basal segments post-systolic shortening time and cardiac index (r = -0.64, r(2) = 0.41, p = 0.001), accounting for the significant correlation between RV-SD4 and cardiac index (r = 0.57, r(2) = 0.32, p = 0.003). In IPAH with narrow QRS, RV dyssynchrony is associated with RV dilation and eccentric hypertrophy pattern, suggesting a role of segmental wall stress heterogeneity as the major determinant of mechanical delay. Post-systolic shortening, as inefficient contraction, contributes to pump dysfunction. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Differential modulation of right ventricular strain and right atrial mechanics in mild vs. severe pressure overload

PubMed Central

Voeller, Rochus K.; Aziz, Abdulhameed; Maniar, Hersh S.; Ufere, Nneka N.; Taggar, Ajay K.; Bernabe, Noel J.; Cupps, Brian P.

2011-01-01

Increased right atrial (RA) and ventricular (RV) chamber volumes are a late maladaptive response to chronic pulmonary hypertension. The purpose of the current investigation was to characterize the early compensatory changes that occur in the right heart during chronic RV pressure overload before the development of chamber dilation. Magnetic resonance imaging with radiofrequency tissue tagging was performed on dogs at baseline and after 10 wk of pulmonary artery banding to yield either mild RV pressure overload (36% rise in RV pressure; n = 5) or severe overload (250% rise in RV pressure; n = 4). The RV free wall was divided into three segments within a midventricular plane, and circumferential myocardial strain was calculated for each segment, the septum, and the left ventricle. Chamber volumes were calculated from stacked MRI images, and RA mechanics were characterized by calculating the RA reservoir, conduit, and pump contribution to RV filling. With mild RV overload, there were no changes in RV strain or RA function. With severe RV overload, RV circumferential strain diminished by 62% anterior (P = 0.04), 42% inferior (P = 0.03), and 50% in the septum (P = 0.02), with no change in the left ventricle (P = 0.12). RV filling became more dependent on RA conduit function, which increased from 30 ± 9 to 43 ± 13% (P = 0.01), than on RA reservoir function, which decreased from 47 ± 6 to 33 ± 4% (P = 0.04), with no change in RA pump function (P = 0.94). RA and RV volumes and RV ejection fraction were unchanged from baseline during either mild (P > 0.10) or severe RV pressure overload (P > 0.53). In response to severe RV pressure overload, RV myocardial strain is segmentally diminished and RV filling becomes more dependent on RA conduit rather than reservoir function. These compensatory mechanisms of the right heart occur early in chronic RV pressure overload before chamber dilation develops. PMID:21926343

PUCA pump and IABP comparison: analysis of hemodynamic and energetic effects using a digital computer model of the circulation.

PubMed

Fresiello, Libera; Gu, Y John; Ferrari, Gianfranco; Di Molfetta, Arianna; Rakhorst, Gerhard

2011-05-01

The pulsatile catheter pump (PUCA pump) is a left ventricular assist device that provides additional flow to the left ventricle. It is usually run in order to ensure a counterpulsation effect, as in the case of the intra-aortic balloon pump (IABP). Because of this similarity, a comparison between the PUCA pump and the IABP was conducted from both the hemodynamic and energetic points of view. Numerical models of the two devices were created and connected to the CARDIOSIM cardiovascular simulator. The PUCA and IABP models were then verified using in vivo experimental data and literature data, respectively. Numerical experiments were conducted for different values of left ventricular end systolic elastance (Els) and systemic arterial compliance (Csa). The energetic comparison was conducted taking into account the diastolic pressure time index and the endocardial viability ratio. Hemodynamic results expressed as cardiac output (CO) and mean coronary blood flow (CBF) show that both the IABP and the PUCA pump efficacy decrease with higher values of Els and Csa. The IABP especially shows higher sensitivity to these parameters, to the extent that in some cases CO actually drops and CBF does not increase. On the other hand, for lower values of Csa, IABP performance improves so much that the PUCA pump flow needs to be increased in order to ensure a hemodynamic effect comparable to that of the IABP. Energetic results show a trend similar to the hemodynamic ones. The study will be continued by investigating other energetic variables and the autonomic response of the cardiovascular system.

Methods for measuring right ventricular function and hemodynamic coupling with the pulmonary vasculature.

PubMed

Bellofiore, Alessandro; Chesler, Naomi C

2013-07-01

The right ventricle (RV) is a pulsatile pump, the efficiency of which depends on proper hemodynamic coupling with the compliant pulmonary circulation. The RV and pulmonary circulation exhibit structural and functional differences with the more extensively investigated left ventricle (LV) and systemic circulation. In light of these differences, metrics of LV function and efficiency of coupling to the systemic circulation cannot be used without modification to characterize RV function and efficiency of coupling to the pulmonary circulation. In this article, we review RV physiology and mechanics, established and novel methods for measuring RV function and hemodynamic coupling, and findings from application of these methods to RV function and coupling changes with pulmonary hypertension. We especially focus on non-invasive measurements, as these may represent the future for clinical monitoring of disease progression and the effect of drug therapies.

Heartmate 3 fully magnetically levitated left ventricular assist device for the treatment of advanced heart failure -1 year results from the Ce mark trial.

PubMed

Krabatsch, Thomas; Netuka, Ivan; Schmitto, Jan D; Zimpfer, Daniel; Garbade, Jens; Rao, Vivek; Morshuis, Michiel; Beyersdorf, Friedhelm; Marasco, Silvana; Damme, Laura; Pya, Yuriy

2017-04-04

The HeartMate 3 Left Ventricular Assist System (LVAS) (St. Jude Medical Inc., St Paul, MN) with full magnetic levitation allows for wide and consistent blood flow paths and an artificial pulse designed for enhanced hemocompatibility. The HeartMate 3 received market approval in the European Union in 2015 following completion of a multicenter study. After reaching the 6-month study endpoint, patients continue to be followed for 2 years with the 1-year results presented herein. A prospective, non-randomized study included adults with advanced heart failure and ejection fraction (EF) ≤ 25%, cardiac index (CI) ≤ 2.2 L/min/m2 while not on inotropes, or inotrope dependent, or on optimal medical management for 45/60 days. Fifty patients-54% bridge to transplant (BTT) and 46% destination therapy (DT)-were enrolled and implanted with the HeartMate 3. At baseline, 92% of the patients were INTERMACS profiles 2-4, with cardiac index 1.8 + 0.5 L/min/m 2 and 58% were supported with inotropes. At 1 year, 74% of the patients remain on support, 18% expired, 6% transplanted, and 2% explanted. The adverse events include 12% gastrointestinal bleeding, 16% driveline infections, 18% strokes, and 2% outflow graft thrombosis. There was no hemolysis, pump thrombosis or pump malfunction through 1 year. The six-minute walk test distance increased from a mean of 273 m to 371 m (P <0.0001). EQ-5D quality-of-life score increased from a mean of 52.7 to 70.8 (P = 0.0006). The 1-year HeartMate 3 LVAS results show survival and adverse-event profile are similar to other approved devices, with no pump thrombosis or pump failure. Patient's functional status and quality of life significantly improved over time. Clinicaltrials.gov registration number: NCT02170363 . Registered June 19, 2014.

Computational model based approach to analysis ventricular arrhythmias: Effects of dysfunction calcium channels

NASA Astrophysics Data System (ADS)

Gulothungan, G.; Malathi, R.

2018-04-01

Disturbed sodium (Na+) and calcium (Ca2+) handling is known to be a major predisposing factor for life-threatening cardiac arrhythmias. Cardiac contractility in ventricular tissue is prominent by Ca2+ channels like voltage dependent Ca2+ channels, sodium-calcium exchanger (Na+-Ca2+x) and sacroplasmicrecticulum (SR) Ca2+ pump and leakage channels. Experimental and clinical possibilities for studying cardiac arrhythmias in human ventricular myocardium are very limited. Therefore, the use of alternative methods such as computer simulations is of great importance. Our aim of this article is to study the impact on action potential (AP) generation and propagation in single ventricular myocyte and ventricular tissue under different dysfunction Ca2+ channels condition. In enhanced activity of Na+-Ca2+x, single myocyte produces AP duration (APD90) and APD50 is significantly smaller (266 ms and 235 ms). Its Na+-Ca2+x current at depolarization is increases 60% from its normal level and repolarization current goes more negative (nonfailing= -0.28 pA/pF and failing= -0.47 pA/pF). Similarly, same enhanced activity of Na+-Ca2+x in 10 mm region of ventricular sheet, raises the plateau potential abruptly, which ultimately affects the diastolic repolarization. Compare with normal ventricular sheet region of 10 mm, 10% of ventricular sheet resting state is reduces and ventricular sheet at time 250 ms is goes to resting state very early. In hypertrophy condition, single myocyte produces APD90 and APD50 is worthy of attention smaller (232 mS and 198 ms). Its sodium-potassium (Na+-K+) pump current is 75% reduces from its control conditions (0.13 pA/pF). Hypertrophy condition, 50% of ventricular sheet is reduces to minimum plateau potential state, that starts the repolarization process very early and reduces the APD. In a single failing SR Ca2+ channels myocyte, recovery of Ca2+ concentration level in SR reduces upto 15% from its control myocytes. At time 290 ms, 70% of ventricular sheet is in dysfunction resting potential state in the range -83 mV and ventricular sheet at time 295 ms is goes to 65% dysfunction resting state. Therefore we concluded that shorter APD, instability resting potential and affected calcium induced calcium release (CICR) due to dysfunction Ca2+ channels is potentially have a substantial effect on cardiac contractility and relaxation. Computational study on ventricular tissue AP and its underlying ionic channel currents could help to elucidate possible arrhythmogenic mechanism on a cellular level.

Left ventricular assist device malfunction: a systematic approach to diagnosis.

PubMed

Horton, Steven C; Khodaverdian, Reza; Powers, Amanda; Revenaugh, James; Renlund, Dale G; Moore, Stephanie A; Rasmusson, Brad; Nelson, Karl E; Long, James W

2004-05-05

A protocol was designed to diagnose the common malfunctions of a left ventricular assist device (LVAD). Mechanical circulatory support, primarily with an LVAD, is increasingly used for treatment of advanced heart failure (HF). Left ventricular assist device dysfunction is a recognized complication; but heretofore, a systematic method to accurately diagnose LVAD dysfunction has not been thoroughly described. We developed a catheter-based protocol designed to characterize a normally functioning LVAD and diagnose multiple types of dysfunction. A total of 15 studies of 10 patients supported with an LVAD were reviewed. All patients had been evaluated due to concerns regarding LVAD dysfunction. Of 15 examinations performed, 11 documented severe LVAD inflow valve regurgitation. One of these cases proved to have coexistent severe mitral valve regurgitation. One case was diagnosed with distortion of the LVAD outflow graft. One case of suspected embolization from the pumping chamber excluded the outflow graft as the source of emboli. One study had aortic insufficiency. As LVAD use for treatment of end-stage HF becomes widespread and durations of support are extended, dysfunction will be increasingly prevalent. This catheter-based protocol provided a practical method to diagnose multiple causes of LVAD dysfunction.

First use of an untethered, vented electric left ventricular assist device for long-term support.

PubMed

Frazier, O H

1994-06-01

This report describes the first long-term (505-day) application of the vented electric (VE) HeartMate left ventricular assist device (LVAD) (Thermo Cardiosystems, Inc). The device consists of an abdominally placed, battery-powered titanium blood pump that, in contrast to earlier pneumatically powered systems, allows patients untethered freedom of movement. The batteries last 5 to 8 hours and can be changed on a rotating basis indefinitely. The patient, a 33-year-old man (90 kg, blood type O) with idiopathic cardiomyopathy, experienced end-organ heart failure (New York Heart Association [NYHA] class IV) while he was awaiting heart transplantation. When his hemodynamic criteria met those outlined in the protocol, we implanted the VE-LVAD as a bridge to transplantation. The patient was supported by the device for more than 16 months. His cardiac status returned to NYHA class I, and he was eventually allowed to take day trips outside the hospital as he awaited transplantation. The VE-LVAD enabled the patient to participate in activities such as eating in restaurants, going to movies, and practicing basketball shots. Unfortunately, the patient died suddenly due to a neurological thromboembolic event that occurred on day 503 of VE-LVAD support. The VE-LVAD improved native left ventricular function by chronic unloading, and ventricular remodeling resulted in a more normal configuration anatomically, physiologically, and ultimately, histologically and pathologically.

Successful repair of a ventricular assist system percutaneous lead.

PubMed

Pantalos, G M; Marks, J D; Richardson, E E; Nelson, K E; Long, J W

1999-01-01

A patient with an implanted, electrically powered, ventricular assist device (Thermo Cardiosystems VE HeartMate) experienced a partial break of the percutaneous lead 5 months after implantation. The break (limited to the Silicone rubber tube) occurred at the junction of the lead with the Y-connector to the controller and vent, leaving approximately 5 cm of exposed lead from the skin exit site to the connector. Electronic and pumping functions of the pump continued, but the opening in the lead (which went more that half way around the circumference) prevented the use of pneumatic actuation as a back-up mode for pump operation, and placed the pump at risk for contamination. Repair of the lead without surgical intervention was desirable, with ease of repair and minimal risk to the patient being the top priorities. The use of multiple layers of heat-shrink tubing or external metal stents was ruled out in favor of a three stage repair procedure. The first stage involved the removal of the Dacron velour in-growth material from the lead to expose the underlying Silicone rubber tube. While the opening in the tube was held shut, a coating of medical grade Silicone rubber adhesive was applied to the tube, then wrapped with a woven Dacron mesh, followed by two layers of plastic wrapping material to protect the adhesive. This initial layer was secured by an external stent of tubing with cable ties. After several days to allow for complete curing of the adhesive, the adhesive coating with mesh was repeated. The final step involved a double layer wrap of a 1 mm thick Silicone rubber sheeting with mesh incorporation and adhesive secured in place with cable ties. After completion of the repair and verification of the ability to operate the device with pneumatic actuation, the patient was discharged with no recurrence of the problem after 8 months of weekly follow-up. This experience demonstrates the need to clinically anticipate component repair or replacement without total device replacement in future implantable blood pump systems.

Muscle powered blood pump: design and initial test results.

PubMed

Trumble, D R; Magovern, J A

1999-01-01

A pneumatic ventricular assist device (Sarns/3M) has been redesigned for low volume hydraulic actuation to accommodate muscle powered drive systems. Design modifications include adding a bellows/piston mechanism (to compress the blood sac) and a compliance chamber for volume compensation. A simple prototype device was constructed to measure the efficacy of piston pump actuation and to validate pusher plate design. Device manufacture was affected by removing the drive line housing from the pneumatic pump and replacing it with a piston/bushing mechanism. A convex piston profile was chosen to maximize ejection fraction and minimize device size. Stroke volume was found to be a linear function of piston displacement (approximately 3 ml/mm) and reached a maximum value of 45 ml. Mean compression forces of 46-56 N acting during a 12 mm stroke (2.1 L/min at 60 cycles/min) were sufficient to generate mean afterload pressures of 70-110 mm Hg in a mock circulatory loop. Peak compression forces ranged from 72 to 86 N and work input was calculated to be 552-672 mJ/stroke. These data indicate that this method for delivering muscle power to the bloodstream is both mechanically viable and compatible with the functional capacity of conditioned latissimus dorsi muscle.

Animal trials of a Magnetically Levitated Left-Ventricular Assist Device

NASA Technical Reports Server (NTRS)

Paden, Brad; Antaki, James; Groom, Nelson

2000-01-01

The University of Pittsburgh/Magnetic Moments mag-lev left-ventricular assist devices (LVADs), the Streamliner HG3b and HG3c, have successfully been implanted in calves. The first was implanted for 4 hours on July 10, 1998 and the second for 34 days on August 24, 1999 respectively. The tests confirmed the feasibility of low power levitation (1.5 watts coil power) and very low blood damage in a mag-lev ventricular assist device. In this paper, we describe the unique geometry of this pump and its design. Key features of this LVAD concept are the passive radial suspension and active voice-coil thrust bearing.

Computational analysis of the effect of valvular regurgitation on ventricular mechanics using a 3D electromechanics model.

PubMed

Lim, Ki Moo; Hong, Seung-Bae; Lee, Byong Kwon; Shim, Eun Bo; Trayanova, Natalia

2015-03-01

Using a three-dimensional electromechanical model of the canine ventricles with dyssynchronous heart failure, we investigated the relationship between severity of valve regurgitation and ventricular mechanical responses. The results demonstrated that end-systolic tension in the septum and left ventricular free wall was significantly lower under the condition of mitral regurgitation (MR) than under aortic regurgitation (AR). Stroke work in AR was higher than that in MR. On the other hand, the difference in stroke volume between the two conditions was not significant, indicating that AR may cause worse pumping efficiency than MR in terms of consumed energy and performed work.

Understanding the C-pulse device and its potential to treat heart failure.

PubMed

Sales, Virna L; McCarthy, Patrick M

2010-03-01

The Sunshine Heart C-Pulse (C-Pulse; Sunshine Heart Inc., Tustin, CA) device is an extra-aortic implantable counterpulsation pump designed as a non-blood contacting ambulatory heart assist device, which may provide relief from symptoms for class II-III congestive heart failure patients. It has a comparable hemodynamic augmentation to intra-aortic balloon counterpulsation devices. The C-Pulse cuff is implanted through a median sternotomy, secured around the ascending aorta, and pneumatically driven by an external system controller. Pre-clinical studies in the acute pig model, and initial temporary clinical studies in patients undergoing off-pump coronary bypass surgery have shown substantial increase in diastolic perfusion of the coronary vessels, which translated to a favorable improvement in ventricular function. A U.S. prospective multi-center trial to evaluate the safety and efficacy of the C-Pulse in class III patients with moderate heart failure is now in progress.

Studies of turbulence models in a computational fluid dynamics model of a blood pump.

PubMed

Song, Xinwei; Wood, Houston G; Day, Steven W; Olsen, Don B

2003-10-01

Computational fluid dynamics (CFD) is used widely in design of rotary blood pumps. The choice of turbulence model is not obvious and plays an important role on the accuracy of CFD predictions. TASCflow (ANSYS Inc., Canonsburg, PA, U.S.A.) has been used to perform CFD simulations of blood flow in a centrifugal left ventricular assist device; a k-epsilon model with near-wall functions was used in the initial numerical calculation. To improve the simulation, local grids with special distribution to ensure the k-omega model were used. Iterations have been performed to optimize the grid distribution and turbulence modeling and to predict flow performance more accurately comparing to experimental data. A comparison of k-omega model and experimental measurements of the flow field obtained by particle image velocimetry shows better agreement than k-epsilon model does, especially in the near-wall regions.

Physiological pump loading of isolated cardiac muscle.

PubMed

Paulus, W J; Claes, V A; Brutsaert, D L

1976-05-01

Cat papillary muscles were subjected to a continuously changing load, resulting from an analysis of the left ventricle as a muscle pump system. The papillary muscle was assumed to be part of a circumferential bundle of muscle fibers of a simplified ejecting ventricle. The load included the pressure--stress relationship of this ventricle and the peripheral vascular load with its inertial, resistive and capacitive components. When this loading function was imposed on a shortening muscle through an electronic feedback circuit, the time course of force development and the velocity versus force plots closely resembled data obtained in the intact heart. Analysis of mechanical work (delta 1 X f) and power (V X f) and their respective time course permitted distinction between changes of contractile performance due to (1) positive or negative inotropic interventions, (2) altered hypothetical ventricular dimensions and changed preload, and (3) the long-term load-dependent memory of cardiac muscle.

Effect of high altitude exposure on the hemodynamics of the bidirectional Glenn physiology: modeling incremented pulmonary vascular resistance and heart rate.

PubMed

Vallecilla, Carolina; Khiabani, Reza H; Sandoval, Néstor; Fogel, Mark; Briceño, Juan Carlos; Yoganathan, Ajit P

2014-06-03

The considerable blood mixing in the bidirectional Glenn (BDG) physiology further limits the capacity of the single working ventricle to pump enough oxygenated blood to the circulatory system. This condition is exacerbated under severe conditions such as physical activity or high altitude. In this study, the effect of high altitude exposure on hemodynamics and ventricular function of the BDG physiology is investigated. For this purpose, a mathematical approach based on a lumped parameter model was developed to model the BDG circulation. Catheterization data from 39 BDG patients at stabilized oxygen conditions was used to determine baseline flows and pressures for the model. The effect of high altitude exposure was modeled by increasing the pulmonary vascular resistance (PVR) and heart rate (HR) in increments up to 80% and 40%, respectively. The resulting differences in vascular flows, pressures and ventricular function parameters were analyzed. By simultaneously increasing PVR and HR, significant changes (p <0.05) were observed in cardiac index (11% increase at an 80% PVR and 40% HR increase) and pulmonary flow (26% decrease at an 80% PVR and 40% HR increase). Significant increase in mean systemic pressure (9%) was observed at 80% PVR (40% HR) increase. The results show that the poor ventricular function fails to overcome the increased preload and implied low oxygenation in BDG patients at higher altitudes, especially for those with high baseline PVRs. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different PVR increments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dependence of intramyocardial pressure and coronary flow on ventricular loading and contractility: a model study.

PubMed

Bovendeerd, Peter H M; Borsje, Petra; Arts, Theo; van De Vosse, Frans N

2006-12-01

The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity.

The Effect of Milrinone on the Right Ventriclular Function in Patients with Reduced Right Ventricular Function Undergoing Off-pump Coronary Artery Bypass Graft Surgery

PubMed Central

Lee, Jong Hwa; Oh, Young Jun; Shim, Yon Hee; Hong, Yong Woo; Yi, Gijong

2006-01-01

This investigation evaluated the effect of continuous milrinone infusion on right ventriclular (RV) function during off-pump coronary artery bypass graft (OPCAB) surgery in patients with reduced RV function. Fifty patients scheduled for OPCAB, with thermodilution RV ejection fraction (RVEF) <35% after anesthesia induction, were randomly allocated to either milrinone (0.5 µg/kg/min) or control (saline) group. Hemodynamic variables and RV volumetric data measured by thermodilution method were collected as follows: after anesthesia induction (T1); 10 min after heart displacement for obtuse marginal artery anastomosis (T2); after pericardial closure (T3). Cardiac index and heart rate increased and systemic vascular resistance significantly decreased in milrinone group at T2. Initially lower RVEF of milrinone group was eventually comparable to control group after milrinone infusion. RVEF did not significantly change at T2 and T3 in both groups. RV end-diastolic volume in milrinone group consistently decreased from the baseline at T2 and T3. Continuous infusion of milrinone without a bolus demonstrated potentially beneficial effect on cardiac output and RV afterload in patients with reduced RV function during OPCAB. However, aggressive augmentation of intravascular volume seems to be necessary to maximize the effect of the milrinone in these patients. PMID:17043419

Implantation of a HeartMate II left ventricular assist device via left thoracotomy.

PubMed

Cho, Yang Hyun; Deo, Salil V; Schirger, John A; Pereira, Naveen L; Stulak, John M; Park, Soon J

2012-11-01

Left thoracotomy was used as an approach for the implantation of pulsatile ventricular assist devices. Avoiding the standard approach of median sternotomy is attractive in patients undergoing complicated redo cardiac surgery, especially with prior mediastinal radiation. We report a case of the use of left thoracotomy for the implantation of the HeartMate II axial-flow pump. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

An electronic circuit that detects left ventricular ejection events by processing the arterial pressure waveform

NASA Technical Reports Server (NTRS)

Gebben, V. D.; Webb, J. A., Jr.

1972-01-01

An electronic circuit for processing arterial blood pressure waveform signals is described. The circuit detects blood pressure as the heart pumps blood through the aortic valve and the pressure distribution caused by aortic valve closure. From these measurements, timing signals for use in measuring the left ventricular ejection time is determined, and signals are provided for computer monitoring of the cardiovascular system. Illustrations are given of the circuit and pressure waveforms.

Left-to-right shunt reduction with intra-aortic balloon pump in postmyocardial infarction ventricular septal defect.

PubMed

Testuz, Ariane; Roffi, Marco; Bonvini, Robert Francis

2013-03-01

This case aims to describe the hemodynamic effects of intra-aortic balloon pump (IABP) in patients with ventricular septal defect (VSD) complicating myocardial infarction (MI). A 79-year-old man with no previous cardiovascular history presented to the emergency department with subacute inferior myocardial infarction associated with mild signs of systemic hypoperfusion. A transthoracic echocardiography revealed a large akinesia of the left ventricular inferior wall with preserved global left ventricular ejection fraction, as well as a large VSD in the midinferior portion of the interventricular septum. Coronary angiography showed an occlusion of the mid portion of a dominant circumflex coronary artery. The invasive hemodynamic evaluation showed a sizable left-to-right shunt (Q(p)/Q(s) = 3.1). Activation of the IABP led to an immediate reduction of the shunt (Q(p)/Q(s) = 2.4 = 22% reduction), an increase in systemic cardiac output (from 2.1 L/min to 2.4 L/min = +12%) and a decrease in the systemic vascular resistances (from 2240 to 1920 dyne-sec/cm(5) = 15% reduction). In patients with post-MI VSD, placement of IABP leads to an immediate reduction in left-to-right shunt and as a consequence to an increase in systemic cardiac output, which may allow hemodynamic stabilization of the patient prior to surgical VSD closure. Copyright © 2012 Wiley Periodicals, Inc.

Early Feasibility Testing and Engineering Development of the Transapical Approach for the HeartWare MVAD Ventricular Assist System

PubMed Central

Tamez, Daniel; LaRose, Jeffrey A.; Shambaugh, Charles; Chorpenning, Katherine; Soucy, Kevin G; Sobieski, Michael A; Sherwood, Leslie; Giridharan, Guruprasad A; Monreal, Gretel; Koenig, Steven C; Slaughter, Mark S

2014-01-01

Implantation of ventricular assist devices (VADs) for treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. VAD implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc. (Miami Lakes, FL) has developed a platform of miniature ventricular devices with progressively reduced surgical invasiveness and innovative patient peripherals. One surgical implant concept is a transapical version of the miniaturized left ventricular assist device (MVAD). The HeartWare MVAD Pump® is a small, continuous flow, full-support device that has a displacement volume of 22mL. A new cannula configuration has been developed for transapical implantation, where the outflow cannula is positioned across the aortic valve. The two primary objectives for this feasibility study were to evaluate anatomic fit and surgical approach and efficacy of the transapical MVAD configuration. Anatomic fit and surgical approach were demonstrated using human cadavers (n=4). Efficacy was demonstrated in acute (n =2) and chronic (n = 1) bovine model experiments and assessed by improvements in hemodynamics, biocompatibility, flow dynamics, and histopathology. Potential advantages of the MVAD Pump include flow support in the same direction as the native ventricle, elimination of cardiopulmonary bypass, and minimally-invasive implantation. PMID:24399057

Blood Pump Development Using Rocket Engine Flow Simulation Technology

NASA Technical Reports Server (NTRS)

Kiris, Cetin C.; Kwak, Dochan

2002-01-01

This viewgraph presentation provides information on the transfer of rocket engine flow simulation technology to work involving the development of blood pumps. Details are offered regarding the design and requirements of mechanical heart assist devices, or VADs (ventricular assist device). There are various computational fluid dynamics issues involved in the visualization of flow in such devices, and these are highlighted and compared to those of rocket turbopumps.

Blood Pump Development Using Rocket Engine Flow Simulation Technology

NASA Technical Reports Server (NTRS)

Kwak, Dochan; Kiris, Cetin

2001-01-01

This paper reports the progress made towards developing complete blood flow simulation capability in humans, especially in the presence of artificial devices such as valves and ventricular assist devices. Devices modeling poses unique challenges different from computing the blood flow in natural hearts and arteries. There are many elements needed to quantify the flow in these devices such as flow solvers, geometry modeling including flexible walls, moving boundary procedures and physiological characterization of blood. As a first step, computational technology developed for aerospace applications was extended to the analysis and development of a ventricular assist device (VAD), i.e., a blood pump. The blood flow in a VAD is practically incompressible and Newtonian, and thus an incompressible Navier-Stokes solution procedure can be applied. A primitive variable formulation is used in conjunction with the overset grid approach to handle complex moving geometry. The primary purpose of developing the incompressible flow analysis capability was to quantify the flow in advanced turbopump for space propulsion system. The same procedure has been extended to the development of NASA-DeBakey VAD that is based on an axial blood pump. Due to massive computing requirements, high-end computing is necessary for simulating three-dimensional flow in these pumps. Computational, experimental, and clinical results are presented.

In vivo biocompatibility evaluation of a new resilient, hard-carbon, thin-film coating for ventricular assist devices.

PubMed

Takaseya, Tohru; Fumoto, Hideyuki; Shiose, Akira; Arakawa, Yoko; Rao, Santosh; Horvath, David J; Massiello, Alex L; Mielke, Nicole; Chen, Ji-Feng; Zhou, Qun; Dessoffy, Raymond; Kramer, Larry; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

2010-12-01

The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Current progress in the development of a totally implantable Gyro centrifugal artificial heart.

PubMed

Takami, Y; Ohtsuka, G; Mueller, J; Ebner, M; Tayama, E; Ohashi, Y; Taylor, D; Fernandes, J; Schima, H; Schmallegger, H; Wolner, E; Nosé, Y

1998-01-01

A totally implantable centrifugal artificial heart has been developed using a miniaturized pivot bearing supported centrifugal pump (Gyro PI pump). The authors report current progress in its development. The Gyro PI-601 has a priming volume of 20 ml, weighs 100 g, has a height of 60 mm, and has a diameter of 65 mm. This pump can provide 8 L/min against 150 mmHg at 2,250 rpm. It is driven by an miniaturized DC brushless motor with the coils fixed in a plastic mold that is waterproof and made of titanium (weight, 204 g; height, 18 mm; diameter, 65 mm). In this centrifugal artificial heart, two Gyro PI pumps are implanted independently to replace cardiac function without resecting the native heart. Its anatomic and surgical feasibility were confirmed experimentally. The Gyro PI-601 was implanted as a right or left ventricular assist device in the preperitoneal space of five calves. All five tests proceeded without any thromboembolic symptoms. One of five tests was extended more than 1 month to confirm the long-term feasibility of the Gyro PI-601 pump system. Based on the satisfactory results of the in vivo tests, the material conversion of the Gyro PI from polycarbonate to titanium alloy (Ti-6A1-4V) was undertaken to improve its biocompatibility for long-term implantation.

Intracerebroventricular opiate infusion for refractory head and facial pain

PubMed Central

Lee, Darrin J; Gurkoff, Gene G; Goodarzi, Amir; Muizelaar, J Paul; Boggan, James E; Shahlaie, Kiarash

2014-01-01

AIM: To study the risks and benefits of intracerebroventricular (ICV) opiate pumps for the management of benign head and face pain. METHODS: SSix patients with refractory trigeminal neuralgia and/or cluster headaches were evaluated for implantation of an ICV opiate infusion pump using either ICV injections through an Ommaya reservoir or external ventricular drain. Four patients received morphine ICV pumps and two patientS received a hydromorphone pump. Of the Four patients with morphine ICV pumps, one patient had the medication changed to hydromorphone. Preoperative and post-operative visual analog scores (VAS) were obtained. Patients were evaluated post-operatively for a minimum of 3 mo and the pump dosage was adjusted at each outpatient clinic visit according to the patient’s pain level. RESULTS: All 6 patients had an intracerebroventricular opiate injection trial period, using either an Ommaya reservoir or an external ventricular drain. There was an average VAS improvement of 75.8%. During the trial period, no complications were observed. Pump implantation was performed an average of 3.7 wk (range 1-7) after the trial injections. After implantation, an average of 20.7 ± 8.3 dose adjustments were made over 3-56 mo after surgery to achieve maximal pain relief. At the most recent follow-up (26.2 mo, range 3-56), VAS scores significantly improved from an average of 7.8 ± 0.5 (range 6-10) to 2.8 ± 0.7 (range 0-5) at the final dose (mean improvement 5.0 ± 1.0, P < 0.001). All patients required a stepwise increase in opiate infusion rates to achieve maximal benefit. The most common complications were nausea and drowsiness, both of which resolved with pump adjustments. On average, infusion pumps were replaced every 4-5 years. CONCLUSION: These results suggest that ICV delivery of opiates may potentially be a viable treatment option for patients with intractable pain from trigeminal neuralgia or cluster headache. PMID:25133146

In-hospital outcomes of a minimally invasive off-pump left thoracotomy approach using a centrifugal continuous-flow left ventricular assist device.

PubMed

Sileshi, Bantayehu; Haglund, Nicholas A; Davis, Mary E; Tricarico, Nicole M; Stulak, John M; Khalpey, Zain; Danter, Matthew R; Deegan, Robert; Kennedy, Jason; Keebler, Mary E; Maltais, Simon

2015-01-01

Minimally invasive left thoracotomy (MILT) and off-pump implantation strategies have been anecdotally reported for implantation of the HeartWare ventricular assist device (HVAD). We analyzed our experience with off-pump MILT implantation techniques and compared early in-hospital outcomes with conventional on-pump sternotomy (CS) implantation strategy. Between January 2013 and February 2014, 51 patients underwent HVAD implantation and were included in this study. Thirty-three patients had CS, whereas 18 patients underwent off-pump MILT. To compare outcomes of these techniques, a multivariate analysis using propensity score modeling was performed after adjusting for age, INTERMACS, Kormos and Leitz-Miller (LM) scores. Mean age at implant was 57 (range 18 to 69) years, and overall in-hospital mortality was 8%. Univariate analysis revealed a statistically significant reduction in days on inotropes (p = 0.04), and a trend toward reduced intra-operative blood product administration (p = 0.08) in the MILT group. There was no difference in intensive-care-unit length of stay (p = 0.5), total length of stay (p = 0.76), post-operative blood product administration (p = 0.34) and total time on mechanical ventilation (p = 0.32). After adjusting for age, INTERMACS profile and Kormos and LM scores, no statistically significant differences were observed between the MILT and CS groups. An off-pump MILT implantation strategy can be utilized as a safe surgical approach for patients undergoing HVAD implantation. Further large collaborative studies are needed to identify advantages of the MILT approach. Published by Elsevier Inc.

Development of a miniature motor-driven pulsatile LVAD driven by a fuzzy controller.

PubMed

Okamoto, Eiji; Makino, Tsutomu; Tanaka, Shuji; Yasuda, Takahiko; Akasaka, Yuta; Tani, Makiko; Inoue, Yusuke; Mitoh, Ayumu; Mitamura, Yoshinori

2007-01-01

We have been developing a small, lightweight motor-driven pulsatile left ventricular assist device (LVAD) with a ball screw. The motor-driven LVAD consists of a brushless DC motor and a ball screw. The attractive magnetic force between Nd-Fe-B magnets (with a diameter of 5 mm and a thickness of 1.5 mm) mounted in holes in a silicone rubber sheet (thickness 2 mm) and an iron plate adhered onto the a diaphragm of the blood pump can provide optimum active blood filling during the pump filling phase. The LVAD has a stroke volume of 55 ml and an overall volume of 285 ml; it weighs 360 g. The controller mainly consists of a fuzzy logic position and velocity controller to apply doctors' and engineers' knowledge to control the LVAD. Each unit of the controller consists of a functionally independent program module for easy improvement of the controller's performance. The LVAD was evaluated in in vitro experiments using a mock circulation. A maximum pump outflow of 5.1 l/min was obtained at a drive rate of 95 bpm against an afterload of 95 mmHg, and active filling using the attractive magnetic force provided a pump output of 3.6 l/min at a drive rate of 75 bpm under a preload of 0 mmHg. The operating efficiency of the LVAD was measured at between 8% and 10.5%. While the LVAD can provide adequate pump outflow for cardiac assistance, further upgrading of the software and improvement of the blood pump are required to improve pump performance and efficiency.

Maintenance of valvular integrity with Impella left heart support: Results from the multicenter PROTECT II randomized study.

PubMed

Goldstein, James A; Dixon, Simon R; Douglas, Pamela S; Ohman, E Magnus; Moses, Jeffrey; Popma, Jeffrey J; O'Neill, William W

2017-10-08

The Impella 2.5 axial flow pump, which is positioned across the aortic valve, is widely employed for hemodynamic support. The present study compared structural and functional integrity of the left heart valves in patients undergoing Impella vs intra-aortic balloon pump in the randomized PROTECT II trial. Transthoracic echocardiograms were performed at baseline, 1 and 3 months in 445 patients in the PROTECT II trial. Serial studies were analyzed by an independent echocardiography core laboratory for aortic and mitral valve structure and function, and left ventricular ejection fraction (LVEF). During Impella support there was no appreciable change in the degree of baseline valvular regurgitation. There were no cases of structural derangement of the mitral or aortic valve after use of the Impella device. At 90-day follow-up, there was an average 22% relative increase in LVEF from baseline (27% ± 9 vs. 33% ± 11, P < 0.001). The present echocardiographic analysis of the PROTECT II study confirms prior observations regarding the safety of the Impella 2.5 device with respect to mitral and aortic valve function. © 2017 Wiley Periodicals, Inc.

Assessment of cardiac autonomic regulation and ventricular repolarization after off-pump coronary artery bypass grafting.

PubMed

Kalisnik, Jurij M; Avbelj, Viktor; Trobec, Roman; Ivaskovic, Daroslav; Vidmar, Gaj; Troise, Giovanni; Gersak, Borut

2006-01-01

Altered autonomic regulation precipitates cardiac arrhythmias and increases the risk of sudden cardiac death. This risk is further increased by changes in ventricular repolarization. Autonomic regulation is deranged in patients after myocardial on-pump revascularization. We aimed to clarify how off-pump coronary artery bypass grafting (CABG) affects postoperative cardiac autonomic regulation and ventricular repolarization within 4 weeks after CABG. Forty-two patients (mean age, 61.9 +/- 9.3 years; mean EURO score 2.6 +/- 1.9) were electively admitted for off-pump CABG. The electrocardiographic and respiratory waveform recordings were performed in the afternoon in the supine position for 10 minutes. Autonomic modulation was assessed using heart rate variability analysis. Power spectra were computed from 5-minute stable RR intervals using Fourier Transform analysis. Total power of spectra was defined in the range of 0.01 to 0.40 Hz, high-frequency power within 0.15 to 0.40 Hz, and low-frequency power within 0.04 to 0.15 Hz. Normalized power was defined as a ratio of power in each band/total power. The high- and low-frequency power as well as their normalized values indicated cardiac vagal and sympathetic modulation, respectively. Ventricular repolarization was assessed using QT interval, QT interval variability, and QT-RR interdependence analysis. QT intervals were determined from the beginning of the 5-minute segments. QT interval variability was evaluated by a T-wave template-matching algorithm. Pearson correlation between length of RR and QT interval was applied to study QT-RR characteristics. The results were tested for significance using the Fisher exact test, nonpaired t test, and analysis of variance; a P <.05 was considered significant. The frequency of arrhythmic events and heart rate increased from the fourth to the seventh postoperative day and returned to preoperative levels 4 weeks after CABG. Heart rate variability measures indicating autonomic modulation remained depressed even 4 weeks after the procedure. QT variability index increased from -1.2 +/- 0.5 to -0.8 +/- 0.4 on the fourth day after the operation (P <.05) and returned to -1.0 +/- 0.5 4 weeks after CABG (P = not significant). QT-RR correlation decreased from 0.41 to 0.23 (P <.05) and remained significantly impaired as long as 4 weeks after CABG. Observed faster heart rates until 1 week after off-pump CABG imply excessive adrenergic activation, which is comparable to on-pump CABG procedure rates. The results indicate profound autonomic derangement and loss of rate-dependent regulation after off-pump CABG even 4 weeks after operation. Restituted repolarization as assessed by QT variability index 4 weeks postoperatively corresponded with decreased frequency of rhythm disturbances 4 weeks after CABG. The loss of coupling between QT and RR intervals shows increased electrical instability postoperatively, which may serve as an additional promoter for postoperative arrhythmias, especially at higher heart rates.

Cardiac dysfunction in heart failure: the cardiologist's love affair with time.

PubMed

Brutsaert, Dirk L

2006-01-01

Translating research into clinical practice has been a challenge throughout medical history. From the present review, it should be clear that this is particularly the case for heart failure. As a consequence, public awareness of this disease has been disillusionedly low, despite its prognosis being worse than that of most cancers and many other chronic diseases. We explore how over the past 150 years since Ludwig and Marey concepts about the evaluation of cardiac performance in patients with heart failure have emerged. From this historical-physiologic perspective, we have seen how 3 increasingly reductionist approaches or schools of thought have evolved in parallel, that is, an input-output approach, a hemodynamic pump approach, and a muscular pump approach. Each one of these has provided complementary insights into the pathophysiology of heart failure and has resulted in measurements or derived indices, some of which still being in use in present-day cardiology. From the third, most reductionist muscular pump approach, we have learned that myocardial and ventricular relaxation properties as well as temporal and spatial nonuniformities have been largely overlooked in the 2 other, input-output and hemodynamic pump, approaches. A key message from the present review is that relaxation and nonuniformities can be fully understood only from within the time-space continuum of cardiac pumping. As cyclicity and rhythm are, in some way, the most basic aspects of cardiac function, considerations of time should dominate over any measurement of cardiac performance as a muscular pump. Any measurement that is blind for the arrow of cardiac time should therefore be interpreted with caution. We have seen how the escape from the time domain-as with the calculation of LV ejection fraction-fascinating though as it may be, has undoubtedly served to hinder a rational scientific debate on the recent, so-called systolic-diastolic heart failure controversy. Lacking appreciation of early relaxation abnormalities and inappropriate degrees of nonuniformities has, indeed, led to some unfortunate misunderstandings about the pathophysiologic time progression of heart failure, in particular, heart failure with compensated hemodynamic pump function (ie, with normal or preserved LV ejection fraction). We have seen that with the introduction of newer powerful diagnostic techniques, as, for example, TDI and MRI, to evaluate ventricular "muscular pump" function, this debate can now be held in a more serene physiologic context. These aspects will be elaborated further in subsequent chapter papers of this symposium. With ongoing stem and other cell-based therapies and future reductionistic insights into cardiac cellular performance, we foresee the emergence of a fourth simple-parallel school of thought viewing the heart as a network of communicating different cell types, that is, cardiomyocytes, endothelial cells, fibroblasts, neurons. In this postgenomic age with the introduction of the rapidly evolving discipline of in vivo molecular imaging techniques, we anticipate that novel measurements of cardiac performance in patients with heart failure will soon become available and complement biopsy and other already available cardiac cellular biomarkers (cardiac troponin I; creatine kinase-MB; myoglobin; BNP). Through the use of these novel biomarkers as a fourth diagnostic track in the evaluation of cardiac performance in patients with heart failure, we will soon be able to increasingly understand the behavior of the heart as a complex biologic system-in other words, how these "low-level" biologic functions and signal transduction pathways at a cellular level contribute to the above "high-level" or system-level approach of cardiac performance at the muscular, the hemodynamic, and the input-output pump system levels and, hopefully, how they could contribute to an early diagnosis of chronic heart failure, in patients.

Left ventricular volume analysis as a basic tool to describe cardiac function.

PubMed

Kerkhof, Peter L M; Kuznetsova, Tatiana; Ali, Rania; Handly, Neal

2018-03-01

The heart is often regarded as a compression pump. Therefore, determination of pressure and volume is essential for cardiac function analysis. Traditionally, ventricular performance was described in terms of the Starling curve, i.e., output related to input. This view is based on two variables (namely, stroke volume and end-diastolic volume), often studied in the isolated (i.e., denervated) heart, and has dominated the interpretation of cardiac mechanics over the last century. The ratio of the prevailing coordinates within that paradigm is termed ejection fraction (EF), which is the popular metric routinely used in the clinic. Here we present an insightful alternative approach while describing volume regulation by relating end-systolic volume (ESV) to end-diastolic volume. This route obviates the undesired use of metrics derived from differences or ratios, as employed in previous models. We illustrate basic principles concerning ventricular volume regulation by data obtained from intact animal experiments and collected in healthy humans. Special attention is given to sex-specific differences. The method can be applied to the dynamics of a single heart and to an ensemble of individuals. Group analysis allows for stratification regarding sex, age, medication, and additional clinically relevant covariates. A straightforward procedure derives the relationship between EF and ESV and describes myocardial oxygen consumption in terms of ESV. This representation enhances insight and reduces the impact of the metric EF, in favor of the end-systolic elastance concept advanced 4 decades ago.

Device Management and Flow Optimization on Left Ventricular Assist Device Support.

PubMed

Tchoukina, Inna; Smallfield, Melissa C; Shah, Keyur B

2018-07-01

The authors discuss principles of continuous flow left ventricular assist device (LVAD) operation, basic differences between the axial and centrifugal flow designs and hemodynamic performance, normal LVAD physiology, and device interaction with the heart. Systematic interpretation of LVAD parameters and recognition of abnormal patterns of flow and pulsatility on the device interrogation are necessary for clinical assessment of the patient. Optimization of pump flow using LVAD parameters and echocardiographic and hemodynamics guidance are reviewed. Copyright © 2018 Elsevier Inc. All rights reserved.

The Use of Computational Fluid Dynamics in the Development of Ventricular Assist Devices

PubMed Central

Fraser, Katharine H.; Taskin, M. Ertan; Griffith, Bartley P.; Wu, Zhongjun J.

2010-01-01

Progress in the field of prosthetic cardiovascular devices has significantly contributed to the rapid advancements in cardiac therapy during the last four decades. The concept of mechanical circulatory assistance was established with the first successful clinical use of heart-lung machines for cardiopulmonary bypass. Since then a variety of devices have been developed to replace or assist diseased components of the cardiovascular system. Ventricular assist devices (VADs) are basically mechanical pumps designed to augment or replace the function of one or more chambers of the failing heart. Computational Fluid Dynamics (CFD) is an attractive tool in the development process of VADs, allowing numerous different designs to be characterized for their functional performance virtually, for a wide range of operating conditions, without the physical device being fabricated. However, VADs operate in a flow regime which is traditionally difficult to simulate; the transitional region at the boundary of laminar and turbulent flow. Hence different methods have been used and the best approach is debatable. In addition to these fundamental fluid dynamic issues, blood consists of biological cells. Device-induced biological complications are a serious consequence of VAD use. The complications include blood damage (haemolysis, blood cell activation), thrombosis and emboli. Patients are required to take anticoagulation medication constantly which may cause bleeding. Despite many efforts blood damage models have still not been implemented satisfactorily into numerical analysis of VADs, which severely undermines the full potential of CFD. This paper reviews the current state of the art CFD for analysis of blood pumps, including a practical critical review of the studies to date, which should help device designers choose the most appropriate methods; a summary of blood damage models and the difficulties in implementing them into CFD; and current gaps in knowledge and areas for future work. PMID:21075669

Using extracorporeal membrane oxygenation support preoperatively and postoperatively as a successful bridge to recovery in a patient with a large infarct-induced ventricular septal defect.

PubMed

Jacob, Samuel; Patel, Mitesh J; Lima, Brian; Felius, Joost; Malyala, Rajasekhar S; Chamogeorgakis, Themistokles; MacHannaford, Juan C; Gonzalez-Stawinski, Gonzalo V; Rafael, Aldo E

2016-07-01

Rupture of the ventricular septum during acute myocardial infarction usually occurs within the first week. The event is usually followed by low cardiac output, heart failure, and multiorgan failure. Despite the many advances in the nonoperative treatment of heart failure and cardiogenic shock, including the intra-aortic balloon pump and a multitude of new inotropic agents and vasodilators, these do not supplant the need for operative intervention in these critically ill patients. This article describes the successful use of extracorporeal membrane oxygenation support as a bridge to recovery postoperatively in a patient with a large infarct-produced ventricular septal defect.

Using extracorporeal membrane oxygenation support preoperatively and postoperatively as a successful bridge to recovery in a patient with a large infarct-induced ventricular septal defect

PubMed Central

Jacob, Samuel; Patel, Mitesh J.; Lima, Brian; Felius, Joost; Malyala, Rajasekhar S.; Chamogeorgakis, Themistokles; MacHannaford, Juan C.; Gonzalez-Stawinski, Gonzalo V.

2016-01-01

Rupture of the ventricular septum during acute myocardial infarction usually occurs within the first week. The event is usually followed by low cardiac output, heart failure, and multiorgan failure. Despite the many advances in the nonoperative treatment of heart failure and cardiogenic shock, including the intra-aortic balloon pump and a multitude of new inotropic agents and vasodilators, these do not supplant the need for operative intervention in these critically ill patients. This article describes the successful use of extracorporeal membrane oxygenation support as a bridge to recovery postoperatively in a patient with a large infarct-produced ventricular septal defect. PMID:27365878

No Electromagnetic Interference Occurred in a Patient with a HeartMate II Left Ventricular Assist System and a Subcutaneous Implantable Cardioverter-Defibrillator.

PubMed

Raman, Ajay Sundara; Shabari, Farshad Raissi; Kar, Biswajit; Loyalka, Pranav; Hariharan, Ramesh

2016-04-01

The use of subcutaneous implantable cardioverter-defibrillators is a novel option for preventing arrhythmia-mediated cardiac death in patients who are at risk of endovascular-device infection or in whom venous access is difficult. However, the potential for electromagnetic interference between subcutaneous defibrillators and left ventricular assist devices is largely unknown. We report the case of a 24-year-old man in whom we observed no electromagnetic interference between a subcutaneous implanted cardioverter-defibrillator and a HeartMate II Left Ventricular Assist System, at 3 different pump speeds. To our knowledge, this is the first report of such findings in this circumstance.

No Electromagnetic Interference Occurred in a Patient with a HeartMate II Left Ventricular Assist System and a Subcutaneous Implantable Cardioverter-Defibrillator

PubMed Central

Raman, Ajay Sundara; Kar, Biswajit; Loyalka, Pranav; Hariharan, Ramesh

2016-01-01

The use of subcutaneous implantable cardioverter-defibrillators is a novel option for preventing arrhythmia-mediated cardiac death in patients who are at risk of endovascular-device infection or in whom venous access is difficult. However, the potential for electromagnetic interference between subcutaneous defibrillators and left ventricular assist devices is largely unknown. We report the case of a 24-year-old man in whom we observed no electromagnetic interference between a subcutaneous implanted cardioverter-defibrillator and a HeartMate II Left Ventricular Assist System, at 3 different pump speeds. To our knowledge, this is the first report of such findings in this circumstance. PMID:27127441

Long-term animal experiments with an intraventricular axial flow blood pump.

PubMed

Yamazaki, K; Kormos, R L; Litwak, P; Tagusari, O; Mori, T; Antaki, J F; Kameneva, M; Watach, M; Gordon, L; Mukuo, H; Umezu, M; Tomioka, J; Outa, E; Griffith, B P; Koyanagai, H

1997-01-01

A miniature intraventricular axial flow blood pump (IVAP) is undergoing in vivo evaluation in calves. The IVAP system consists of a miniature (phi 13.9 mm) axial flow pump that resides within the left ventricular (LV) chamber and a brushless DC motor. The pump is fabricated from titanium alloy, and the pump weight is 170 g. It produces a flow rate of over 5 L/min against 100 mmHg pressure at 9,000 rpm with an 8 W total power consumption. The maximum total efficiency exceeds 17%. A purged lip seal system is used in prototype no. 8, and a newly developed "Cool-Seal" (a low temperature mechanical seal) is used in prototype no. 9. In the Cool-Seal system, a large amount of purge flow is introduced behind the seal faces to augment convective heat transfer, keeping the seal face temperature at a low level for prevention of heat denaturation of blood proteins. The Cool-Seal system consumes < 10 cc purge fluid per day and has greatly extended seal life. The pumps were implanted in three calves (26, 30, and 168 days of support). The pump was inserted through a left thoracotomy at the fifth intercostal space. Two pursestring sutures were placed on the LV apex, and the apex was cored with a myocardial punch. The pump was inserted into the LV with the outlet cannula smoothly passing through the aortic valve without any difficulty. Only 5 min elapsed between the time of chest opening and initiation of pumping. Pump function remained stable throughout in all experiments. No cardiac arrhythmias were detected, even at treadmill exercise tests. The plasma free hemoglobin level remained in the acceptable range. Post mortem examination did not reveal any interference between the pump and the mitral apparatus. No major thromboembolism was detected in the vital organs in Cases 1 or 2, but a few small renal infarcts were detected in Case 3.

Recent progress in the development of Terumo implantable left ventricular assist system.

PubMed

Nojiri, C; Kijima, T; Maekawa, J; Horiuchi, K; Kido, T; Sugiyama, T; Mori, T; Sugiura, N; Asada, T; Shimane, H; Ozaki, T; Suzuki, M; Akamatsu, T; Akutsu, T

1999-01-01

The research group of the Terumo Corporation, the NTN Corporation, and Setsunan University (T. Akamatsu) has been developing an implantable left ventricular assist system (ILVAS) featuring a centrifugal blood pump with a magnetically suspended impeller (MSCP). The impeller of the MSCP is suspended by a magnetic bearing, providing contact-free rotation of the impeller inside the pump housing. Thus the MSCP is expected to provide years of long-term durability. Ex vivo chronic sheep experiments using the extracorporeal model (Model I) demonstrated long-term durability, nonthrombogenicity, and a low hemolysis rate (plasma free Hb <6 mg/dl) for more than 2 years. The prototype implantable model (Model II; 196 ml, 400 g) was evaluated ex vivo in 2 sheep and intrathoracically implanted in a small sheep (45 kg). These experiments were terminated at 70, 79, and 17 days, respectively, because of blood leakage through the connector system within the housing of Model II. There was no thrombus formation on the retrieved pump surfaces. A new connector system was introduced to the Model II pump (modified Model II), and the pump was intrathoracically implanted in a sheep. Pump flow rate was maintained at 3-7 L/min at 1700-1800 rpm. The temperature elevation on the surfaces of the motor and the electromagnet inside the pump casing was kept less than 6 degrees C. The temperature of the tissue adjacent to the pump casing became normal 10 days postoperatively. The sheep survived for more than 5 months without any sign of mechanical failure or thromboembolic complication. In vitro real-time endurance tests of motor bearings made of stainless steel and silicone nitride have been conducted for more than 1 year without any sign of bearing wear. The next prototype system (Model III), with an implantable controller and a new MSCP with reduced input power, has been developed with a view toward a totally implantable LVAS.

Using hybrid magnetic bearings to completely suspend the impeller of a ventricular assist device.

PubMed

Khanwilkar, P; Olsen, D; Bearnson, G; Allaire, P; Maslen, E; Flack, R; Long, J

1996-06-01

Clinically available blood pumps and those under development suffer from poor mechanical reliability and poor biocompatibility related to anatomic fit, hemolysis, and thrombosis. To alleviate these problems concurrently in a long-term device is a substantial challenge. Based on testing the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist device, the CFVAD4, for long-term use. The design process and its outcome, the CFVAD4 system configuration, is described. To provide unprecedented reliability and biocompatibility, magnetic bearings completely suspend the rotating pump impeller. The CFVAD4 uses a combination of passive (permanent) and active (electric) magnetic bearings, a mixed flow impeller, and a slotless 3-phase brushless DC motor. These components are shaped, oriented, and integrated to provide a compact, implantable, pancake-shaped unit for placement in the left upper abdominal quadrant of adult humans.

Postimplant left ventricular assist device fit analysis using three-dimensional reconstruction.

PubMed

Truong, Thang V; Stanfield, J Ryan; Chaffin, John S; Elkins, C Craig; Kanaly, Paul J; Horstmanshof, Douglas A; Long, James W; Snyder, Trevor A

2013-01-01

Left ventricular assist devices (LVADs) are blood pumps that augment the function of the failing heart to improve perfusion, resulting in improved survival. For LVADs to effectively unload the left ventricle, the inflow cannula (IC) should be unobstructed and ideally aligned with the heart's mitral valve (MV). We examined IC orientation deviation from a hypothesized conventional angle (45° right-posterior) and the approximate angle for direct IC-MV alignment in many patients. Three-dimensional anatomic models were created from computed tomography scans for 24 LVAD-implanted patients, and angles were measured between the IC and the apical z-axis in both the coronal and the sagittal planes. Common surgical IC angulation was found to be 22 ± 15° rightward and 21 ± 12° posterior from the apical z-axis; 38% (n = 9) of patients fell in this range. Direct IC-MV angulation was found to be 34 ± 8° rightward and 15 ± 7° posterior; only 8% (n = 2) of patients fell in this range. Rightward deviation toward ventricular septal wall and anterior deviation toward LV anterior freewall are associated with mortalities more so than leftward and posterior deviation. In conclusion, anatomic reconstruction may be a useful preoperative tool to obtain general population and patient-specific alignment for optimal LVAD implantation.

Dependence of Intramyocardial Pressure and Coronary Flow on Ventricular Loading and Contractility: A Model Study

PubMed Central

Borsje, Petra; Arts, Theo; van De Vosse, Frans N.

2006-01-01

The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity. PMID:17048105

Early ventricular tachyarrhythmias after coronary artery bypass grafting surgery: Is it a real burden?

PubMed

Mouws, Elisabeth M J P; Yaksh, Ameeta; Knops, Paul; Kik, Charles; Boersma, Eric; Bogers, Ad J J C; de Groot, Natasja M S

2017-09-01

The prevalence of ventricular dysrhythmias (VD) [ventricular premature beats (VPBs), ventricular couplets (Vcouplets), ventricular runs (Vruns)] after coronary artery bypass grafting (CABG) has so far not been examined. The goal of this study is to examine characteristics of VD and whether they precede ventricular tachyarrhythmias (VTA) during a postoperative follow-up period of 5 days using continuous rhythm registrations. In addition, we determined predictive factors of VD/VTA. Incidences and burdens of VD/VTA were calculated in patients (N=105, 83 male, 65±9 years) undergoing primary, on-pump CABG. Independent risk factors were examined using multivariate analysis. VPBs, Vcouplets, and Vruns occurred in respectively 100%, 82.9%, and 48.6% with corresponding burdens of 0.05%, 0%, and 0%. Sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) did not occur in our cohort. Independent risk factors for VD included male gender, mitral valve insufficiency, hyperlipidemia, and age ≥60 years. VD are common in patients with coronary artery disease after CABG. Despite high incidences of these dysrhythmias, corresponding burdens are low and sustained VT or VF did not occur. Incidences were highest on the first postoperative day and diminished over time. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Loss or Inhibition of uPA or MMP-9 Attenuates LV Remodeling and Dysfunction after Acute Pressure Overload in Mice

PubMed Central

Heymans, Stephane; Lupu, Florea; Terclavers, Sven; Vanwetswinkel, Bjorn; Herbert, Jean-Marc; Baker, Andrew; Collen, Desire; Carmeliet, Peter; Moons, Lieve

2005-01-01

Left ventricular (LV) hypertrophy is a natural response of the heart to increased pressure loading, but accompanying fibrosis and dilatation may result in irreversible life-threatening heart failure. Matrix metalloproteinases (MMPs) have been invoked in various cardiac diseases, however, direct genetic evidence for a role of the plasminogen activator (PA) and MMP systems in pressure overload-induced LV hypertrophy and in heart failure is lacking. Therefore, the consequences of transverse aortic banding (TAB) were analyzed in mice lacking tissue-type PA (t-PA−/−), urokinase-type PA (u-PA−/−), or gelatinase-B (MMP-9−/−), and in wild-type (WT) mice after adenoviral gene transfer of the PA-inhibitor PAI-1 or the MMP-inhibitor TIMP-1. TAB elevated LV pressure comparably in all genotypes. In WT and t-PA−/− mice, cardiomyocyte hypertrophy was associated with myocardial fibrosis, LV dilatation and dysfunction, and pump failure after 7 weeks. In contrast, in u-PA−/− mice or in WT mice after PAI-1- and TIMP-1-gene transfer, cardiomyocyte hypertrophy was moderate and only minimally associated with cardiac fibrosis and LV dilatation, resulting in better preservation of pump function. Deficiency of MMP-9 had an intermediate effect. These findings suggest that the use of u-PA- or MMP-inhibitors might preserve cardiac pump function in LV pressure overloading. PMID:15631996

Computational Flow Analysis of a Left Ventricular Assist Device

NASA Technical Reports Server (NTRS)

Kiris, Cetin; Kwak, Dochan; Benkowski, Robert

1995-01-01

Computational fluid dynamics has been developed to a level where it has become an Indispensable part of aerospace research and design. Technology developed foe aerospace applications am also be utilized for the benefit of human health. For example, a flange-to-flange rocket engine fuel-pump simulation includes the rotating and non-rotating components: the flow straighteners, the impeller, and diffusers A Ventricular Assist Device developed by NASA Johnson Space Center and Baylor College of Medicine has a design similar to a rocket engine fuel pump in that it also consists of a flow straightener, an impeller, and a diffuser. Accurate and detailed knowledge of the flowfield obtained by incompressible flow calculations can be greatly beneficial to designers in their effort to reduce the cost and improve the reliability of these devices. In addition to the geometric complexities, a variety of flow phenomena are encountered in biofluids Then include turbulent boundary layer separation, wakes, transition, tip vortex resolution, three-dimensional effects, and Reynolds number effects. In order to increase the role of Computational Fluid Dynamics (CFD) in the design process the CFD analysis tools must be evaluated and validated so that designers gain Confidence in their use. The incompressible flow solver, INS3D, has been applied to flow inside of a liquid rocket engine turbopump components and extensively validated. This paper details how the computational flow simulation capability developed for liquid rocket engine pump component analysis has bean applied to the Left Ventricular Assist Device being developed jointly by NASA JSC and Baylor College of Medicine.

Nursing care of the ambulatory patient with a mechanical assist device.

PubMed

Reedy, J E; Ruzevich, S A; Noedel, N R; Vitale, L J; Merkle, E J

1990-01-01

Since 1986, 10 men and one woman were ambulatory while supported with mechanical assist devices as a bridge to heart transplantation. Four patients received a subclavian intraaortic balloon pump, two were supported with a Novacor left ventricular assist system, three patients received Pierce-Donachy ventricular assist devices, and one patient received a Jarvik 7 total artificial heart. One patient with an intraaortic balloon pump later received a left ventricular assist system because of hemodynamic deterioration despite the intraaortic balloon pump. Before device insertion all 11 patients were in cardiogenic shock despite inotropic and vasodilator support. The time of support ranged from 8 to 440 days (median, 24 days). In-house coverage by the circulatory support team was necessary only during the first 24 to 72 hours of support. When the patient's condition was stabilized, nursing staff monitored the devices with "on-call" availability of the circulatory support team. After implant of the device, all patients were able to perform activities of daily living. Once patients were able to walk in their hospital rooms, ambulation began in the hallways; frequency and distance were gradually increased. Four of the patients walked outside the hospital while tethered to the drive console. Daily physical therapy contributed to increased exercise tolerance. Protective isolation was used before and after transplantation to minimize the risk of infection. Sterile dressing changes (gown, gloves, mask) were applied to drive lines, cannula sites, and incisions. All invasive lines and catheters were removed as soon as the patient's clinical condition warranted, and noninvasive monitoring was used to decrease the chance of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Early feasibility evaluation of thoracoscopically assisted transcatheter ventricular reconstruction in an experimental model of ischaemic heart failure with left anteroapical aneurysm.

PubMed

Cheng, Yanping; Yi, Geng-Hua; Annest, Lon S; Van Bladel, Kevin; Brown, Ryan; Wechsler, Andrew; Shibuya, Masahiko; Conditt, Gerard B; Peppas, Athanasios; Kaluza, Greg L; Granada, Juan F

2015-04-01

To test the feasibility of a thoracoscopically assisted, off-pump, transcatheter ventricular reconstruction (TCVR) approach in an ovine model of left ventricular (LV) anteroapical aneurysm. Myocardial infarction (MI) was induced by coil occlusion of the middle left anterior descending artery and diagonals. Two months after MI creation, TCVR was performed via a minimal thoracotomy in eight sheep. Under endoscopic and fluoroscopic guidance, trans-interventricular septal puncture was performed from the LV epicardial scar. A guidewire was externalised via a snare placed in the right ventricle from the external jugular vein. An internal anchor was inserted over the wire and positioned on the right ventricular septum and an external anchor was deployed on the LV anterior epicardium. Serial pairs of anchors were placed and plicated together to exclude the scar completely. Immediately after TCVR, echocardiography showed LV end-systolic volume decreased from pre-procedure 58.8±16.6 ml to 25.1±7.6 ml (p<0.01) and the ejection fraction increased from 32.0±7.3% to 52.0±7.5% (p<0.01). LV twist significantly improved (3.83±2.21 vs. pre-procedure -0.41±0.94, p=0.01) and the global peak-systolic longitudinal strain increased from -5.64% to -10.77% (p<0.05). TCVR using minimally invasive access techniques on the off-pump beating heart is feasible and resulted in significant improvement in LV performance.

Lung physiology during ECS resuscitation of DCD donors followed by in situ assessment of lung function.

PubMed

Reoma, Junewai L; Rojas, Alvaro; Krause, Eric M; Obeid, Nabeel R; Lafayette, Nathan G; Pohlmann, Joshua R; Padiyar, Niru P; Punch, Jeffery D; Cook, Keith E; Bartlett, Robert H

2009-01-01

Extracorporeal cardiopulmonary support (ECS) of donors after cardiac death (DCD) has been shown to improve abdominal organs for transplantation. This study assesses whether pulmonary congestion occurs during ECS with the heart arrested and describes an in vivo method to assess if lungs are suitable for transplantation from DCD donors after ECS resuscitation. Cardiac arrest was induced in 30 kg pigs, followed by 10 min of warm ischemia. Cannulae were placed into the right atrium (RA) and iliac artery, and veno-arterial ECS was initiated for 90 min with lungs inflated, group 1 (n = 5) or deflated, group 2 (n = 3). Left atrial pressures were measured as a marker for pulmonary congestion. After 90 min of ECS, lung function was evaluated. Cannulae were placed into the pulmonary artery (PA) and left ventricle (LV). A second pump was included, and ECS was converted to a bi-ventricular (bi-VAD) system. The RVAD drained from the RA and pumped into the PA, and the LVAD drained the LV and pumped into the iliac. This brought the lungs back into circulation for a 1-hr assessment period. The oxygenator was turned off, and ventilation was restarted. Flows, blood gases, PA and left atrial pressures, and compliance were recorded. In both the groups, LA pressure was <15 mm Hg during ECS. During the lung assessment period, PA flows were 1.4-2.2 L/min. PO2 was >300 mm Hg, with normal PCO2. Extracorporeal cardiopulmonary support resuscitation of DCD donors is feasible and allows for assessment of function before procurement. Extracorporeal cardiopulmonary support does not cause pulmonary congestion, and the lungs retain adequate function for transplantation. Compliance correlated with lung function.

Computational Fluid Dynamics (CFD) study of the 4th generation prototype of a continuous flow Ventricular Assist Device (VAD).

PubMed

Song, Xinwei; Wood, Houston G; Olsen, Don

2004-04-01

The continuous flow ventricular assist device (VAD) is a miniature centrifugal pump, fully suspended by magnetic bearings, which is being developed for implantation in humans. The CF4 model is the first actual prototype of the final design product. The overall performances of blood flow in CF4 have been simulated using computational fluid dynamics (CFD) software: CFX, which is commercially available from ANSYS Inc. The flow regions modeled in CF4 include the inlet elbow, the five-blade impeller, the clearance gap below the impeller, and the exit volute. According to different needs from patients, a wide range of flow rates and revolutions per minute (RPM) have been studied. The flow rate-pressure curves are given. The streamlines in the flow field are drawn to detect stagnation points and vortices that could lead to thrombosis. The stress is calculated in the fluid field to estimate potential hemolysis. The stress is elevated to the decreased size of the blood flow paths through the smaller pump, but is still within the safe range. The thermal study on the pump, the blood and the surrounding tissue shows the temperature rise due to magnetoelectric heat sources and thermal dissipation is insignificant. CFD simulation proved valuable to demonstrate and to improve the performance of fluid flow in the design of a small size pump.

Preoperative intra-aortic balloon pump improves the clinical outcomes of off-pump coronary artery bypass grafting in left ventricular dysfunction patients

PubMed Central

Yang, Feng; Wang, Jinhong; Hou, Dengbang; Xing, Jialin; Liu, Feng; Xing, Zhi chen; Jiang, Chunjing; Hao, Xing; Du, Zhongtao; Yang, Xiaofang; Zhao, Yanyan; Miao, Na; Jiang, Yu; Dong, Ran; Gu, Chengxiong; Sun, Lizhong; Wang, Hong; Hou, Xiaotong

2016-01-01

Severe left ventricular (LV) dysfunction patients undergoing off-pump coronary artery bypass grafting (OPCAB) are often associated with a higher mortality. The efficacy and safety of the preoperative prophylactic intra-aortic balloon pump (IABP) insertion is not well established. 416 consecutive patients with severe LV dysfunction (ejection fraction ≤35%) undergoing isolated OPCAB were enrolled in a retrospective observational study. 191 patients was enrolled in the IABP group; the remaining 225 patients was in control group. A total of 129 pairs of patients were propensity-score matched. No significant differences in demographic and preoperative risk factors were found between the two groups. The postoperative 30-day mortality occurred more frequently in the control group compared with the IABP group (8.5% vs. 1.6%, p = 0.02). There was a significant reduction of low cardiac output syndrome in the IABP group compared with the control group (14% vs. 6.2%, p = 0.04). Prolonged mechanical ventilation (≥48 h) occurred more frequently in the control group (34.9% vs. 20.9%, p = 0.02). IABP also decreased the postoperative length of stay. Preoperative IABP was associated with a lower 30-day mortality, suggesting that it is effective in patients with severe LV dysfunction undergoing OPCAB. PMID:27279591

Model study of ATP and ADP buffering, transport of Ca(2+) and Mg(2+), and regulation of ion pumps in ventricular myocyte

NASA Technical Reports Server (NTRS)

Michailova, A.; McCulloch, A.

2001-01-01

We extended the model of the ventricular myocyte by Winslow et al. (Circ. Res 1999, 84:571-586) by incorporating equations for Ca(2+) and Mg(2+) buffering and transport by ATP and ADP and equations for MgATP regulation of ion transporters (Na(+)-K(+) pump, sarcolemmal and sarcoplasmic Ca(2+) pumps). The results indicate that, under normal conditions, Ca(2+) binding by low-affinity ATP and diffusion of CaATP may affect the amplitude and time course of intracellular Ca(2+) signals. The model also suggests that a fall in ATP/ADP ratio significantly reduces sarcoplasmic Ca(2+) content, increases diastolic Ca(2+), lowers systolic Ca(2+), increases Ca(2+) influx through L-type channels, and decreases the efficiency of the Na(+)/Ca(2+) exchanger in extruding Ca(2+) during periodic voltage-clamp stimulation. The analysis suggests that the most important reason for these changes during metabolic inhibition is the down-regulation of the sarcoplasmic Ca(2+)-ATPase pump by reduced diastolic MgATP levels. High Ca(2+) concentrations developed near the membrane might have a greater influence on Mg(2+), ATP, and ADP concentrations than that of the lower Ca(2+) concentrations in the bulk myoplasm. The model predictions are in general agreement with experimental observations measured under normal and pathological conditions.

Long-Term Durability Test for the Left Ventricular Assist System EVAHEART under the Physiologic Pulsatile Load.

PubMed

Kitano, Tomoya; Iwasaki, Kiyotaka

The EVAHEART Left Ventricular Assist System (LVAS) was designed for the long-term support of a patient with severe heart failure. It has an original water lubrication system for seal and bearing and wear on these parts was considered one of its critical failure modes. A durability test focusing on wear was designed herein. We developed a mock loop, which generates a physiologic pulsatile flow and is sufficiently durable for a long-term test. The pulsatile load and the low fluid viscosity enable the creation of a severe condition for the mechanical seal. A total of 18 EVAHEART blood pumps completed 2 years of operation under the pulsatile condition without any failure. It indicated the EVAHEART blood pump had a greater than 90% reliability with a 88% confidence level. The test was continued with six blood pumps and achieved an average of 8.6 years, which was longer than the longest clinical use in Japan. The test result showed that no catastrophic, critical, marginal, or minor failures of the blood pump or their symptoms were observed. The seal performance was maintained after the test. Moreover, the surface roughness did not change, which showed any burn or abnormal wear occurred. The original water lubrication system equipped in EVAHEART LVAS prevent severe wear on the seal and the bearing, and it can be used in the bridge to transplant and destination therapy.

In vivo evaluation of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

PubMed

Saeed, Diyar; Shalli, Shanaz; Fumoto, Hideyuki; Ootaki, Yoshio; Horai, Tetsuya; Anzai, Tomohiro; Zahr, Roula; Horvath, David J; Massiello, Alex L; Chen, Ji-Feng; Dessoffy, Raymond; Catanese, Jacquelyn; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

2010-06-01

Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14-91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.

Prognostication of valvular aortic stenosis using tissue Doppler echocardiography: underappreciated importance of late diastolic mitral annular velocity.

PubMed

Poh, Kian-Keong; Chan, Mark Yan-Yee; Yang, Hong; Yong, Quek-Wei; Chan, Yiong-Huak; Ling, Lieng H

2008-05-01

Intact left atrial booster pump function helps maintain cardiac compensation in patients with aortic valve stenosis (AS). Because late diastolic mitral annular (A') velocity reflects left atrial systolic function, we hypothesized that A' velocity correlates with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and clinical outcome in AS. We prospectively enrolled 53 consecutive patients (median age 74 years) with variable degrees of AS, in sinus rhythm, and left ventricular ejection fraction greater than 50%. Indices of valvular stenosis, left ventricular diastolic dysfunction, and mitral annular motion were correlated with plasma NT-proBNP and a composite clinical end point comprising cardiac death and symptom-driven aortic valve replacement. Tissue Doppler echocardiographic parameters, including early diastolic (E') velocity and A' velocity and ratio of early diastolic transmitral (E) to E' velocity (E/E') at the annular septum correlated better with NT-proBNP levels than body surface area-indexed aortic valve area. Eighteen patients had the composite end point, which was univariately predicted by body surface area-indexed aortic valve area, NT-proBNP, and all tissue Doppler echocardiographic indices. This outcome was most strongly predicted by the combination of septal A' velocity and E/E' ratio in bivariate Cox modeling. Septal annular A' velocity less than 9.6 cm/s was associated with significantly reduced event-free survival (Kaplan Meier log rank = 27.3, P < .0001) and predicted the end point with a sensitivity, specificity, and accuracy of 94%, 80%, and 85%, respectively. In patients with AS and normal ejection fraction, annular tissue Doppler echocardiographic indices may better reflect the physiologic consequences of afterload burden on the left ventricle than body surface area-indexed aortic valve area. Lower A' velocity is a predictor of cardiac death and need for valve surgery, suggesting an important role for compensatory left atrial booster pump function.

Analysis of pressure head-flow loops of pulsatile rotodynamic blood pumps.

PubMed

Jahren, Silje E; Ochsner, Gregor; Shu, Fangjun; Amacher, Raffael; Antaki, James F; Vandenberghe, Stijn

2014-04-01

The clinical importance of pulsatility is a recurring topic of debate in mechanical circulatory support. Lack of pulsatility has been identified as a possible factor responsible for adverse events and has also demonstrated a role in myocardial perfusion and cardiac recovery. A commonly used method for restoring pulsatility with rotodynamic blood pumps (RBPs) is to modulate the speed profile, synchronized to the cardiac cycle. This introduces additional parameters that influence the (un)loading of the heart, including the timing (phase shift) between the native cardiac cycle and the pump pulses, and the amplitude of speed modulation. In this study, the impact of these parameters upon the heart-RBP interaction was examined in terms of the pressure head-flow (HQ) diagram. The measurements were conducted using a rotodynamic Deltastream DP2 pump in a validated hybrid mock circulation with baroreflex function. The pump was operated with a sinusoidal speed profile, synchronized to the native cardiac cycle. The simulated ventriculo-aortic cannulation showed that the level of (un)loading and the shape of the HQ loops strongly depend on the phase shift. The HQ loops displayed characteristic shapes depending on the phase shift. Increased contribution of native contraction (increased ventricular stroke work [WS ]) resulted in a broadening of the loops. It was found that the previously described linear relationship between WS and the area of the HQ loop for constant pump speeds becomes a family of linear relationships, whose slope depends on the phase shift. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Implantable centrifugal blood pump with dual impeller and double pivot bearing system: electromechanical actuator, prototyping, and anatomical studies.

PubMed

Bock, Eduardo; Antunes, Pedro; Leao, Tarcisio; Uebelhart, Beatriz; Fonseca, Jeison; Leme, Juliana; Utiyama, Bruno; da Silva, Cibele; Cavalheiro, Andre; Filho, Diolino Santos; Dinkhuysen, Jarbas; Biscegli, Jose; Andrade, Aron; Arruda, Celso

2011-05-01

An implantable centrifugal blood pump has been developed with original features for a left ventricular assist device. This pump is part of a multicenter and international study with the objective to offer simple, affordable, and reliable devices to developing countries. Previous computational fluid dynamics investigations and wear evaluation in bearing system were performed followed by prototyping and in vitro tests. In addition, previous blood tests for assessment of normalized index of hemolysis show results of 0.0054±2.46 × 10⁻³ mg/100 L. An electromechanical actuator was tested in order to define the best motor topology and controller configuration. Three different topologies of brushless direct current motor (BLDCM) were analyzed. An electronic driver was tested in different situations, and the BLDCM had its mechanical properties tested in a dynamometer. Prior to evaluation of performance during in vivo animal studies, anatomical studies were necessary to achieve the best configuration and cannulation for left ventricular assistance. The results were considered satisfactory, and the next step is to test the performance of the device in vivo. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Chronic ovine evaluation of a totally implantable electrical left ventricular assist system.

PubMed

Ramasamy, N; Chen, H; Miller, P J; Jassawalla, J S; Greene, B A; Ocampo, A; Siegel, L C; Oyer, P E; Portner, P M

1989-01-01

The totally implantable Novacor left ventricular assist system (LVAS) comprises a pump/drive unit (VAD), electronic control and power subsystem (ECP), variable volume compensator (VVC), and belt skin transformer (BST). The system is now undergoing chronic in vivo evaluation. Cumulative animal testing of VAD, VVC, and BST subsystems are 12.1, 4.9, and 43 years, respectively. The longest implants were 279 days for the VAD, 767 days for the VVC, and 1,148 days for the BST. A chronic implant of the total system was electively terminated at 260 days. The LVAS was powered via the BST. Continuously monitored hemodynamic and pump parameters have demonstrated normal hemodynamics and LVAS operation. Periodic VVC determinations suggest a 0.8 ml/day diffusive gas loss. Tether-free operation has been demonstrated with an Ag-Zn battery backpack. The animal was healthy and free of infection as indicated by routine hematologic, biochemical and serum enzyme determinations. Hemolysis is minimal (plasma free hemoglobin less than 5 mg%). Pump output ranged from 7 to 8 L/min. Severe valve calcification was the reason for elective termination at 260 days. This preclinical in vivo experience, and in vitro reliability studies, demonstrate efficacy of the total system.

The vexing problem of thrombosis in long-term mechanical circulatory support.

PubMed

Mehra, Mandeep R; Stewart, Garrick C; Uber, Patricia A

2014-01-01

Durable left ventricular assist devices (LVADs) have not only enhanced longevity but also conferred sustained improvements in quality of life, symptom control, and functional capacity in patients with medically refractory advanced heart failure. Problems with device-related infection, bleeding, neurologic events, right-sided heart failure, and device malfunction have dominated the clinical care of patients living on mechanical support. Even as adoption of durable LVADs accelerated globally, we began to encounter a growing dilemma of pump malfunction caused by thrombosis. In early 2011, clinicians began to notice a spike in the incidence of pump thrombosis with the HeartMate II (Thoratec Corp, Pleasanton, CA) LVAD. By 2012, the problem of thrombosis in LVADs began to consume most of the scientific direction as centers and collaborative groups began to dissect this nascent phenomenon. In this perspective, we describe the magnitude and implications of pump thrombosis, discuss secular and management trends in this unique population, attempt to dissect the problem at its root, offer guidance on surveillance and therapeutic principles, and outline issues that deserve our immediate and collaborative attention. © 2014 International Society for Heart and Lung Transplantation Published by International Society for the Heart and Lung Transplantation All rights reserved.

Energy transmission and power sources for mechanical circulatory support devices to achieve total implantability.

PubMed

Wang, Jake X; Smith, Joshua R; Bonde, Pramod

2014-04-01

Left ventricular assist device therapy has radically improved congestive heart failure survival with smaller rotary pumps. The driveline used to power today's left ventricular assist devices, however, continues to be a source of infection, traumatic damage, and rehospitalization. Previous attempts to wirelessly power left ventricular assist devices using transcutaneous energy transfer systems have been limited by restrictions on separation distance and alignment between the transmit and receive coils. Resonant electrical energy transfer allows power delivery at larger distances without compromising safety and efficiency. This review covers the efforts to wirelessly power mechanical circulatory assist devices and the progress made in enhancing their energy sources. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Design changes in continuous-flow left ventricular assist devices and life-threatening pump malfunctions.

PubMed

Soltani, Sajjad; Kaufmann, Friedrich; Vierecke, Juliane; Kretzschmar, Alexandra; Hennig, Ewald; Stein, Julia; Hetzer, Roland; Krabatsch, Thomas; Potapov, Evgenij V

2015-06-01

The implantable continuous-flow left ventricular assist devices (LVADs) HeartMate II (HM II) and HeartWare HVAD (HW) underwent design modifications. The impact of these changes on life-threatening pump malfunctions was evaluated. We retrospectively analysed pump malfunctions due to thrombosis or cable damage in patients supported with primarily implanted HM II (n = 191) and HW (n = 347), separated into patients supported with the old and new pump designs. In 2010, the cable strain relief of the HM II device was improved (132 patients with old and 79 with new) and sealed grafts were introduced (68 patients with sealed inflow connector and outflow graft and 125 without). In 2011, titanium sintering of the inflow cannula of HW pumps was introduced (137 patients with a non-sintered and 210 with a sintered inflow cannula). The median support time was 1.12 (0-6.1) years for all HM II and 0.59 (0-4.2) years for all HW patients. The cumulative rate of events per patient-year (EPPY) was 0.11 in HM II patients, compared with 0.09 EPPY in HW patients (P = 0.32). After introduction of the new cable design, incidence of cable damage in HM II patients dropped from 0.06 to 0 EPPY (P = 0.03), whereas pump thrombosis increased from 0.02 to 0.14 EPPY (P < 0.001) after the sealed graft was introduced. Pump thrombosis occurred in 4% of patients supported with HW with a sintered inflow cannula vs 15% with a non-sintered pump; the incidence changed from 0.10 to 0.07 EPPY in sintered pumps (P = 0.45). Kaplan-Meier analysis showed no differences over a period of 2.5 years for events when the HM II cohort with sealed graft and new cable design (n = 68) was compared with the HW group with a sintered cannula (P = 0.14). The modified cable strain relief of the HM II pump and the sintering of the inflow cannula of the HW pump demonstrated a significant reduction in the incidence of life-threatening pump-related complications, whereas the sealed inflow connector and outflow graft seem to be associated with a higher incidence of pump thrombosis. However, the overall incidence of pump-related complications after the latest design changes was similar for both pumps over a 2.5-year period. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Intraventricular flow alterations due to dyssynchronous wall motion

NASA Astrophysics Data System (ADS)

Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

2015-11-01

Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

Left Atrial Pressure Monitoring With an Implantable Wireless Pressure Sensor After Implantation of a Left Ventricular Assist Device

PubMed Central

Baranowski, Jacek; Delshad, Baz; Ahn, Henrik

2017-01-01

After implantation of a continuous-flow left ventricular assist device (LVAD), left atrial pressure (LAP) monitoring allows for the precise management of intravascular volume, inotropic therapy, and pump speed. In this case series of 4 LVAD recipients, we report the first clinical use of this wireless pressure sensor for the long-term monitoring of LAP during LVAD support. A wireless microelectromechanical system pressure sensor (Titan, ISS Inc., Ypsilanti, MI) was placed in the left atrium in four patients at the time of LVAD implantation. Titan sensor LAP was measured in all four patients on the intensive care unit and in three patients at home. Ramped speed tests were performed using LAP and echocardiography in three patients. The left ventricular end-diastolic diameter (cm), flow (L/min), power consumption (W), and blood pressure (mm Hg) were measured at each step. Measurements were performed over 36, 84, 137, and 180 days, respectively. The three discharged patients had equipment at home and were able to perform daily recordings. There were significant correlations between sensor pressure and pump speed, LV and LA size and pulmonary capillary wedge pressure, respectively (r = 0.92–0.99, p < 0.05). There was no device failure, and there were no adverse consequences of its use. PMID:27676410

Interhospital air transport of a blind patient on extracorporeal life support with consecutive and successful left ventricular assist device implantation.

PubMed

Bauer, Adrian; Schaarschmidt, Jan; Grosse, F Oliver; Al Alam, Nidal; Hausmann, Harald; Krämer, Klaus; Strüber, Martin; Mohr, Friedrich W

2014-06-01

The use of extracorporeal life support systems (ECLS) in patients with postcardiotomy low cardiac output syndrome (LCO) as a bridge to recovery and bridge to implantation of ventricular assist device (VAD) is common nowadays. A 59-year-old patient with acute myocardial infarction received a percutaneous transluminal angioplasty and stenting of the circumflex artery. During catheterization of the left coronary artery (LAD), the patient showed ventricular fibrillation and required defibrillation and cardiopulmonary resuscitation. After implantation of an intra-aortic balloon pump, the patient immediately was transmitted to the operating room. He received emergency coronary artery bypass grafting in a beating heart technique using pump-assisted minimal extracorporeal circulation circuit (MECC). Two bypass grafts were performed to the LAD and the right posterior descending artery. Despite initial successful weaning off cardiopulmonary bypass with high-dose inotropic support, the patient presented postcardiotomy LCO and an ECLS was implanted. The primary setup of the heparin-coated MECC system was modified and used postoperatively. As a result of the absence of an in-house VAD program, the patient was switched to a transportable ECLS the next day and was transferred by helicopter to the nearest VAD center where the patient received a successful insertion of a left VAD 3 days later.

Bilirubin attenuates bufadienolide-induced ventricular arrhythmias and cardiac dysfunction in guinea-pigs by reducing elevated intracellular Na(+) levels.

PubMed

Ma, Hongyue; Zhang, Junfeng; Jiang, Jiejun; Zhou, Jing; Xu, Huiqin; Zhan, Zhen; Wu, Qinan; Duan, Jinao

2012-03-01

Bufadienolides, known ligands of the sodium pump, have been shown to inhibit the proliferation of several cancer cell types. However, their development to date as anticancer agents has been impaired by a narrow therapeutic margin resulting from their potential to induce cardiotoxicity. In the present study, we examined the effects of bilirubin, an endogenous antioxidant, on the cardiotoxicity of bufadienolides (derived from toad venom) in guinea-pigs. The results showed that bufadienolides (8 mg/kg) caused ventricular arrhythmias, conduction block, cardiac dysfunction and death in guinea-pigs. Pretreatment with bilirubin (75 and 150 mg/kg) significantly prevented bufadienolide-induced premature ventricular complexes, ventricular tachycardia, ventricular fibrillation and death. Bilirubin also markedly improved the inhibition of cardiac contraction in bufadienolide-treated guinea-pigs as evidenced by increases in left ventricular systolic pressure and decreases in left ventricular diastolic pressure in vivo. Furthermore, bilirubin significantly reduced the intracellular sodium content ([Na(+)]( i )) in ex vivo bufadienolide-stimulated guinea-pig ventricular myocytes loaded with the sodium indicator Sodium Green. An antitumor study showed that bilirubin did not compromise the ability of bufadienolides to inhibit gastric cancer cell MGC-803 proliferation. These results suggested that bilirubin can attenuate bufadienolide-induced arrhythmias and cardiac dysfunction in guinea-pigs by reducing elevated [Na(+)]( i ) and may improve bufadienolide therapeutic index in cancer treatment.

Determinants of kinetic energy of blood flow in the four-chambered heart in athletes and sedentary controls.

PubMed

Steding-Ehrenborg, K; Arvidsson, P M; Töger, J; Rydberg, M; Heiberg, E; Carlsson, M; Arheden, H

2016-01-01

The kinetic energy (KE) of intracardiac blood may play an important role in cardiac function. The aims of the present study were to 1) quantify and investigate the determinants of KE, 2) compare the KE expenditure of intracardiac blood between athletes and control subjects, and 3) quantify the amount of KE inside and outside the diastolic vortex. Fourteen athletes and fourteen volunteers underwent cardiac MRI, including four-dimensional phase-contrast sequences. KE was quantified in four chambers, and energy expenditure was calculated by determining the mean KE/cardiac index. Left ventricular (LV) mass was an independent predictor of diastolic LVKE (R(2) = 0.66, P < 0.001), whereas right ventricular (RV) end-diastolic volume was important for diastolic RVKE (R(2) = 0.76, P < 0.001). The mean KE/cardiac index did not differ between groups (control subjects: 0.53 ± 0.14 mJ·l(-1)·min·m(2) and athletes: 0.56 ± 0.21 mJ·l(-1)·min·m(2), P = 0.98). Mean LV diastolic vortex KE made up 70 ± 1% and 73 ± 2% of total LV diastolic KE in athletes and control subjects (P = 0.18). In conclusion, the characteristics of the LV as a pressure pump and the RV as a volume pump are demonstrated as an association between LVKE and LV mass and between RVKE and end-diastolic volume. This also suggests different filling mechanisms where the LV is dependent on diastolic suction, whereas the RV fills with a basal movement of the atrioventricular plane over "stationary" blood. Both groups had similar energy expenditure for intracardiac blood flow, indicating similar pumping efficiency, likely explained by the lower heart rate that cancels the higher KE per heart beat in athletes. The majority of LVKE is found within the LV diastolic vortex, in contrast to earlier findings. Copyright © 2016 the American Physiological Society.

In vitro characterization of a magnetically suspended continuous flow ventricular assist device.

PubMed

Kim, H C; Bearnson, G B; Khanwilkar, P S; Olsen, D B; Maslen, E H; Allaire, P E

1995-01-01

A magnetically suspended continuous flow ventricular assist device using magnetic bearings was developed aiming at an implantable ventricular assist device. The main advantage of this device includes no mechanical wear and minimal chance of blood trauma such, as thrombosis and hemolysis, because there is no mechanical contact between the stationary and rotating parts. The total system consists of two subsystems: the centrifugal pump and the magnetic bearing. The centrifugal pump is comprised of a 4 vane logarithmic spiral radial flow impeller and a brushless DC motor with slotless stator, driven by the back emf commutation scheme. Two radial and one thrust magnetic bearing that dynamically controls the position of the rotor in a radial and axial direction, respectively, contains magnetic coils, the rotor's position sensors, and feedback electronic control system. The magnetic bearing system was able to successfully suspend a 365.5g rotating part in space and sustain it for up to 5000 rpm of rotation. Average force-current square factor of the magnetic bearing was measured as 0.48 and 0.44 (kg-f/Amp2) for radial and thrust bearing, respectively. The integrated system demonstrated adequate performance in mock circulation tests by providing a 6 L/min flow rate against 100 mmHg differential pressure at 2300 rpm. Based on these in vitro performance test results, long-term clinical application of the magnetically suspended continuous flow ventricular assist device is very promising after system optimization with a hybrid system using both active (electromagnet) and passive (permanent magnets) magnet bearings.

Computational analysis of an axial flow pediatric ventricular assist device.

PubMed

Throckmorton, Amy L; Untaroiu, Alexandrina; Allaire, Paul E; Wood, Houston G; Matherne, Gaynell Paul; Lim, David Scott; Peeler, Ben B; Olsen, Don B

2004-10-01

Longer-term (>2 weeks) mechanical circulatory support will provide an improved quality of life for thousands of pediatric cardiac failure patients per year in the United States. These pediatric patients suffer from severe congenital or acquired heart disease complicated by congestive heart failure. There are currently very few mechanical circulatory support systems available in the United States as viable options for this population. For that reason, we have designed an axial flow pediatric ventricular assist device (PVAD) with an impeller that is fully suspended by magnetic bearings. As a geometrically similar, smaller scaled version of our axial flow pump for the adult population, the PVAD has a design point of 1.5 L/min at 65 mm Hg to meet the full physiologic needs of pediatric patients. Conventional axial pump design equations and a nondimensional scaling technique were used to estimate the PVAD's initial dimensions, which allowed for the creation of computational models for performance analysis. A computational fluid dynamic analysis of the axial flow PVAD, which measures approximately 65 mm in length by 35 mm in diameter, shows that the pump will produce 1.5 L/min at 65 mm Hg for 8000 rpm. Fluid forces (approximately 1 N) were also determined for the suspension and motor design, and scalar stress values remained below 350 Pa with maximum particle residence times of approximately 0.08 milliseconds in the pump. This initial design demonstrated acceptable performance, thereby encouraging prototype manufacturing for experimental validation.

Development and evaluation of endurance test system for ventricular assist devices.

PubMed

Sumikura, Hirohito; Homma, Akihiko; Ohnuma, Kentaro; Taenaka, Yoshiyuki; Takewa, Yoshiaki; Mukaibayashi, Hiroshi; Katano, Kazuo; Tatsumi, Eisuke

2013-06-01

We developed a novel endurance test system that can arbitrarily set various circulatory conditions and has durability and stability for long-term continuous evaluation of ventricular assist devices (VADs), and we evaluated its fundamental performance and prolonged durability and stability. The circulation circuit of the present endurance test system consisted of a pulsatile pump with a small closed chamber (SCC), a closed chamber, a reservoir and an electromagnetic proportional valve. Two duckbill valves were mounted in the inlet and outlet of the pulsatile pump. The features of the circulation circuit are as follows: (1) the components of the circulation circuit consist of optimized industrial devices, giving durability; (2) the pulsatile pump can change the heart rate and stroke length (SL), as well as its compliance using the SCC. Therefore, the endurance test system can quantitatively reproduce various circulatory conditions. The range of reproducible circulatory conditions in the endurance test circuit was examined in terms of fundamental performance. Additionally, continuous operation for 6 months was performed in order to evaluate the durability and stability. The circulation circuit was able to set up a wide range of pressure and total flow conditions using the SCC and adjusting the pulsatile pump SL. The long-term continuous operation test demonstrated that stable, continuous operation for 6 months was possible without leakage or industrial device failure. The newly developed endurance test system demonstrated a wide range of reproducible circulatory conditions, durability and stability, and is a promising approach for evaluating the basic characteristics of VADs.

Assessment of the effect of off-pump coronary artery bypass (OPCAB) surgery on right ventricle function using strain and strain rate imaging.

PubMed

Khani, Mohammad; Hosseintash, Mahsa; Foroughi, Mahnoosh; Naderian, Mohammadreza; Khaheshi, Isa

2016-04-01

Right ventricle function significantly decreases after coronary artery bypass surgery; as one of the likely causes, such a condition is attributed to the use of cardiopulmonary pump (CPB). Because nowadays there is a tendency toward increasing use of off-pump coronary artery bypass (OPCAB) surgery, this study was conducted to evaluate the right ventricle function after this type of surgery using strain and strain rate imaging (SRI) echocardiography. This study was conducted on 30 patients, candidate for elective OPCAB surgery, between 2011 and 2012. Standard echocardiography was performed before the surgery and the right ventricle function was examined using strain and SRI echocardiography. Then patient underwent surgery, 6 days and 3 months after surgery they underwent echocardiography again and the results obtained from the three stages were compared with each other. Participants included 30 patients (23 males and 7 females) with a mean age of 66±11 years. Compared to the prior of the surgery, 6 days and 3 months after the surgery there was a significant decrease in tricuspid annular plane systolic excursion (TAPSE), tissue Doppler imaging (TDI) at the lateral annulus of tricuspid valve, and strain and SRI of right ventricle. However, the values obtained 3 months after surgery were significantly higher than those obtained after 6 days. In other words, the right ventricle function 6 days after the surgery had dropped, however some of the values recovered 3 months after the surgery. The findings of this study are consistent with other studies in this field and showed that after coronary artery surgery a decline occurs in right ventricular function. However, more detailed quantitative strain and SRI parameters which were measured in our study showed that at the early days after the OPCAB surgery there is a decline in the right ventricle function which is relatively reversible at longer intervals (3 months after surgery).

Modelling passive diastolic mechanics with quantitative MRI of cardiac structure and function.

PubMed

Wang, Vicky Y; Lam, H I; Ennis, Daniel B; Cowan, Brett R; Young, Alistair A; Nash, Martyn P

2009-10-01

The majority of patients with clinically diagnosed heart failure have normal systolic pump function and are commonly categorized as suffering from diastolic heart failure. The left ventricle (LV) remodels its structure and function to adapt to pathophysiological changes in geometry and loading conditions, which in turn can alter the passive ventricular mechanics. In order to better understand passive ventricular mechanics, a LV finite element (FE) model was customized to geometric data segmented from in vivo tagged magnetic resonance images (MRI) data and myofibre orientation derived from ex vivo diffusion tensor MRI (DTMRI) of a canine heart using nonlinear finite element fitting techniques. MRI tissue tagging enables quantitative evaluation of cardiac mechanical function with high spatial and temporal resolution, whilst the direction of maximum water diffusion in each voxel of a DTMRI directly corresponds to the local myocardial fibre orientation. Due to differences in myocardial geometry between in vivo and ex vivo imaging, myofibre orientations were mapped into the geometric FE model using host mesh fitting (a free form deformation technique). Pressure recordings, temporally synchronized to the tagging data, were used as the loading constraints to simulate the LV deformation during diastole. Simulation of diastolic LV mechanics allowed us to estimate the stiffness of the passive LV myocardium based on kinematic data obtained from tagged MRI. Integrated physiological modelling of this kind will allow more insight into mechanics of the LV on an individualized basis, thereby improving our understanding of the underlying structural basis of mechanical dysfunction under pathological conditions.

Effects of intra-aortic balloon pump counterpulsation on left ventricular mechanoenergetics in a porcine model of acute ischemic heart failure.

PubMed

Malliaras, Konstantinos; Charitos, Efstratios; Diakos, Nikolaos; Pozios, Iraklis; Papalois, Apostolos; Terrovitis, John; Nanas, John

2014-12-01

We investigated the effects of intra-aortic balloon pump (IABP) counterpulsation on left ventricular (LV) contractility, relaxation, and energy consumption and probed the underlying physiologic mechanisms in 12 farm pigs, using an ischemia-reperfusion model of acute heart failure. During both ischemia and reperfusion, IABP support unloaded the LV, decreased LV energy consumption (pressure-volume area, stroke work), and concurrently improved LV mechanical performance (ejection fraction, stroke volume, cardiac output). During reperfusion exclusively, IABP also improved LV relaxation (tau) and contractility (Emax, PRSW). The beneficial effects of IABP support on LV relaxation and contractility correlated with IABP-induced augmentation of coronary blood flow. In conclusion, we find that during both ischemia and reperfusion, IABP support optimizes LV energetic performance (decreases energy consumption and concurrently improves mechanical performance) by LV unloading. During reperfusion exclusively, IABP support also improves LV contractility and active relaxation, possibly due to a synergistic effect of unloading and augmentation of coronary blood flow.

Using Hybrid Magnetic Bearings to Completely Suspend the Impeller of a Ventricular Assist Device.

PubMed

Khanwilkar, Pratap; Olsen, Don; Bearnson, Gill; Allaire, Paul; Maslen, Eric; Flack, Ron; Long, James

1996-05-01

Clinically available blood pumps and those under development suffer from poor mechanical reliability and poor biocompatibility related to anatomic fit, hemolysis, and thrombosis. To alleviate these problems concurrently in a long-term device is a substantial challenge. Based on testing the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist device, the CF-VAD4, for long-term use. The design process and its outcome, the CFVAD4 system configuration, is described. To provide unprecedented reliability and biocompatibility, magnetic bearings completely suspend the rotating pump impeller. The CFVAD4 uses a combination of passive (permanent) and active (electric) magnetic bearings, a mixed flow impeller, and a slotless 3-phase brushless DC motor. These components are shaped, oriented, and integrated to provide a compact, implantable, pancake-shaped unit for placement in the left upper abdominal quadrant of adult humans. © 1996 International Society for Artificial Organs.

Development and evaluation of a long-term, implantable, electrically actuated left ventricular assist system: THI/Gould LVAS.

PubMed

Norman, J C; McGee, M G; Fuqua, J M; Igo, S R; Turner, S A; Sterling, R; Urrutia, C O; Frazier, O H; Clay, W C; Chambers, J A

1983-02-01

A long-term, implantable, electrically actuated left ventricular assist system (THI/Gould LVAS) is being developed and characterized in vitro and in vivo for utilization in patients with end-stage heart disease. This system consists of five major components: a long-term, implantable blood pump (THI E-type ALVAD); an electrical-mechanical energy converter (Gould Model V); a control unit with batteries; a volume compensation system; and an external power supply and monitoring unit. Two of these components (blood pump and electrical-mechanical energy converter) have been integrated, and are undergoing chronic in vivo evaluations in calves. Thus far, 44 pneumatically and electrically actuated THI/Gould LVAS evaluations have been performed. This experience has resulted in greater than 6.5 years of actuation in vivo, with durations exceeding 1 year. System in vivo performance in terms of durability, mechanical reliability, hemodynamic effectiveness, and biocompatibility has been satisfactory. Demonstration of long-term (2-year) effectiveness in supporting the circulation is the ultimate goal.

The role of the Intra‐aortic balloon pump in supporting children with acute cardiac failure

PubMed Central

Collison, Sathiakar Paul; Dagar, Kulbhusan Singh

2007-01-01

Acute heart failure occurs in children following the operative correction of a congenital anomaly, as an acute change in a child with a congenital anomaly, or in a structurally normal heart with acute myocarditis. Acute heart failure in children justifies aggressive treatment because of the high potential for complete recovery. The options for providing mechanical support to the failing heart in a child include extracorporeal membrane oxygenation, left ventricular assist devices and the use of the intra‐aortic balloon pump (IABP). The principles of intra‐aortic balloon pump usage are described, and the literature regarding the indications and outcome of its use in children is reviewed. PMID:17488858

Pulsatile mechanical cardiac assistance in pediatric patients with the Berlin heart ventricular assist device.

PubMed

Merkle, Frank; Boettcher, Wolfgang; Stiller, Brigitte; Hetzer, Roland

2003-06-01

Mechanical cardiac assistance for neonates, infants, children and adolescents may be accomplished with pulsatile ventricular assist devices (VAD) instead of extracorporeal membrane oxygenation or centrifugal pumps. The Berlin Heart VAD consists of extracorporeal, pneumatically driven blood pumps for pulsatile univentricular or biventricular assistance for patients of all age groups. The blood pumps are heparin-coated. The stationary driving unit (IKUS) has the required enhanced compressor performance for pediatric pump sizes. The Berlin Heart VAD was used in a total number of 424 patients from 1987 to November 2001 at our institution. In 45 pediatric patients aged 2 days-17 years the Berlin Heart VAD was applied for long-term support (1-111 days, mean 20 days). There were three patient groups: Group I: "Bridge to transplantation" with various forms of cardiomyopathy (N = 21) or chronic stages of congenital heart disease (N = 9); Group II: "Rescue" in intractable heart failure after corrective surgery for congenital disease (N = 7) or in early graft failure after heart transplantation (N = 1); and Group III: "Acute myocarditis" (N = 7) as either bridge to transplantation or bridge to recovery. Seventeen patients were transplanted after support periods of between 4 and 111 days with 12 long-term survivors, having now survived for up to 10 years. Five patients (Groups I and III) were weaned from the system with four long-term survivors. In Group II only one patient survived after successful transplantation. Prolonged circulatory support with the Berlin Heart VAD is an effective method for bridging until cardiac recovery or transplantation in the pediatric age group. Extubation, mobilization, and enteral nutrition are possible. For long-term use, the Berlin Heart VAD offers advantages over centrifugal pumps and ECMO in respect to patient mobility and safety.

Wave energy patterns of counterpulsation: a novel approach with wave intensity analysis.

PubMed

Lu, Pong-Jeu; Yang, Chi-Fu Jeffrey; Wu, Meng-Yu; Hung, Chun-Hao; Chan, Ming-Yao; Hsu, Tzu-Cheng

2011-11-01

In counterpulsation, diastolic augmentation increases coronary blood flow and systolic unloading reduces left ventricular afterload. We present a new approach with wave intensity analysis to revisit and explain counterpulsation principles. In an acute porcine model, a standard intra-aortic balloon pump was placed in descending aorta in 4 pigs. We measured pressure and velocity with probes in left anterior descending artery and aorta during and without intra-aortic balloon pump assistance. Wave intensities of aortic and left coronary waves were derived from pressure and flow measurements with synchronization correction. We identified predominating waves in counterpulsation. In the aorta, during diastolic augmentation, intra-aortic balloon inflation generated a backward compression wave, with a "pushing" effect toward the aortic root that translated to a forward compression wave into coronary circulation. During systolic unloading, intra-aortic balloon pump deflation generated a backward expansion wave that "sucked" blood from left coronary bed into the aorta. While this backward expansion wave translated to reduced left ventricular afterload, the "sucking" effect resulted in left coronary blood steal, as demonstrated by a forward expansion wave in left anterior descending coronary flow. The waves were sensitive to inflation and deflation timing, with just 25 ms delay from standard deflation timing leading to weaker forward expansion wave and less coronary regurgitation. Intra-aortic balloon pumps generate backward-traveling waves that predominantly drive aortic and coronary blood flow during counterpulsation. Wave intensity analysis of arterial circulations may provide a mechanism to explain diastolic augmentation and systolic unloading of intra-aortic balloon pump counterpulsation. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Right ventricular pressure response to exercise in adults with isolated ventricular septal defect closed in early childhood.

PubMed

Moller, Thomas; Lindberg, Harald; Lund, May Brit; Holmstrom, Henrik; Dohlen, Gaute; Thaulow, Erik

2018-06-01

We previously demonstrated an abnormally high right ventricular systolic pressure response to exercise in 50% of adolescents operated on for isolated ventricular septal defect. The present study investigated the prevalence of abnormal right ventricular systolic pressure response in 20 adult (age 30-45 years) patients who underwent surgery for early ventricular septal defect closure and its association with impaired ventricular function, pulmonary function, or exercise capacity. The patients underwent cardiopulmonary tests, including exercise stress echocardiography. Five of 19 patients (26%) presented an abnormal right ventricular systolic pressure response to exercise ⩾ 52 mmHg. Right ventricular systolic function was mixed, with normal tricuspid annular plane systolic excursion and fractional area change, but abnormal tricuspid annular systolic motion velocity (median 6.7 cm/second) and isovolumetric acceleration (median 0.8 m/second2). Left ventricular systolic and diastolic function was normal at rest as measured by the peak systolic velocity of the lateral wall and isovolumic acceleration, early diastolic velocity, and ratio of early diastolic flow to tissue velocity, except for ejection fraction (median 53%). The myocardial performance index was abnormal for both the left and right ventricle. Peak oxygen uptake was normal (mean z score -0.4, 95% CI -2.8-0.3). There was no association between an abnormal right ventricular systolic pressure response during exercise and right or left ventricular function, pulmonary function, or exercise capacity. Abnormal right ventricular pressure response is not more frequent in adult patients compared with adolescents. This does not support the theory of progressive pulmonary vascular disease following closure of left-to-right shunts.

Bioengineering an electro-mechanically functional miniature ventricular heart chamber from human pluripotent stem cells.

PubMed

Li, Ronald A; Keung, Wendy; Cashman, Timothy J; Backeris, Peter C; Johnson, Bryce V; Bardot, Evan S; Wong, Andy O T; Chan, Patrick K W; Chan, Camie W Y; Costa, Kevin D

2018-05-01

Tissue engineers and stem cell biologists have made exciting progress toward creating simplified models of human heart muscles or aligned monolayers to help bridge a longstanding gap between experimental animals and clinical trials. However, no existing human in vitro systems provide the direct measures of cardiac performance as a pump. Here, we developed a next-generation in vitro biomimetic model of pumping human heart chamber, and demonstrated its capability for pharmaceutical testing. From human pluripotent stem cell (hPSC)-derived ventricular cardiomyocytes (hvCM) embedded in collagen-based extracellular matrix hydrogel, we engineered a three-dimensional (3D) electro-mechanically coupled, fluid-ejecting miniature human ventricle-like cardiac organoid chamber (hvCOC). Structural characterization showed organized sarcomeres with myofibrillar microstructures. Transcript and RNA-seq analyses revealed upregulation of key Ca 2+ -handling, ion channel, and cardiac-specific proteins in hvCOC compared to lower-order 2D and 3D cultures of the same constituent cells. Clinically-important, physiologically complex contractile parameters such as ejection fraction, developed pressure, and stroke work, as well as electrophysiological properties including action potential and conduction velocity were measured: hvCOC displayed key molecular and physiological characteristics of the native ventricle, and showed expected mechanical and electrophysiological responses to a range of pharmacological interventions (including positive and negative inotropes). We conclude that such "human-heart-in-a-jar" technology could facilitate the drug discovery process by providing human-specific preclinical data during early stage drug development. Copyright © 2018. Published by Elsevier Ltd.

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure.

PubMed

Desai, Ravi R; Vargas Abello, Lina Maria; Klein, Allan L; Marwick, Thomas H; Krasuski, Richard A; Ye, Ying; Nowicki, Edward R; Rajeswaran, Jeevanantham; Blackstone, Eugene H; Pettersson, Gösta B

2013-11-01

To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function. From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+ (100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total. In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+ or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation. In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and temporary. In contrast, concomitant tricuspid valve repair effectively and durably eliminated severe tricuspid regurgitation and improved right ventricular function toward normal, supporting an aggressive approach to important functional tricuspid regurgitation. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure

PubMed Central

Desai, Ravi R.; Vargas Abello, Lina Maria; Klein, Allan L.; Marwick, Thomas H.; Krasuski, Richard A.; Ye, Ying; Nowicki, Edward R.; Rajeswaran, Jeevanantham; Blackstone, Eugene H.; Pettersson, Gösta B.

2014-01-01

Objectives To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function. Methods From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+(100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total. Results In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation. Conclusions In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and temporary. In contrast, concomitant tricuspid valve repair effectively and durably eliminated severe tricuspid regurgitation and improved right ventricular function toward normal, supporting an aggressive approach to important functional tricuspid regurgitation. PMID:23010580

The overloaded right heart and ventricular interdependence.

PubMed

Naeije, Robert; Badagliacca, Roberto

2017-10-01

The right and the left ventricle are interdependent as both structures are nested within the pericardium, have the septum in common and are encircled with common myocardial fibres. Therefore, right ventricular volume or pressure overloading affects left ventricular function, and this in turn may affect the right ventricle. In normal subjects at rest, right ventricular function has negligible interaction with left ventricular function. However, the right ventricle contributes significantly to the normal cardiac output response to exercise. In patients with right ventricular volume overload without pulmonary hypertension, left ventricular diastolic compliance is decreased and ejection fraction depressed but without intrinsic alteration in contractility. In patients with right ventricular pressure overload, left ventricular compliance is decreased with initial preservation of left ventricular ejection fraction, but with eventual left ventricular atrophic remodelling and altered systolic function. Breathing affects ventricular interdependence, in healthy subjects during exercise and in patients with lung diseases and altered respiratory system mechanics. Inspiration increases right ventricular volumes and decreases left ventricular volumes. Expiration decreases both right and left ventricular volumes. The presence of an intact pericardium enhances ventricular diastolic interdependence but has negligible effect on ventricular systolic interdependence. On the other hand, systolic interdependence is enhanced by a stiff right ventricular free wall, and decreased by a stiff septum. Recent imaging studies have shown that both diastolic and systolic ventricular interactions are negatively affected by right ventricular regional inhomogeneity and prolongation of contraction, which occur along with an increase in pulmonary artery pressure. The clinical relevance of these observations is being explored. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Modeling and control of a brushless DC axial flow ventricular assist device.

PubMed

Giridharan, Guruprasad A; Skliar, Mikhail; Olsen, Donald B; Pantalos, George M

2002-01-01

This article presents an integrated model of the human circulatory system that incorporates circulatory support by a brushless DC axial flow ventricular assist device (VAD), and a feedback VAD controller designed to maintain physiologically sufficient perfusion. The developed integrated model combines a network type model of the circulatory system with a nonlinear dynamic model of the brushless DC pump We show that maintaining a reference differential pressure between the left ventricle and aorta leads to adequate perfusion for different pathologic cases, ranging from normal heart to left heart asystole, and widely varying physical activity scenarios from rest to exercise.

Cardiac structure and function, and ventricular-arterial interaction 11 years following a pregnancy with preeclampsia.

PubMed

Al-Nashi, Maha; Eriksson, Maria J; Östlund, Eva; Bremme, Katarina; Kahan, Thomas

2016-04-01

Preeclampsia (PE) is associated with acute left ventricular dysfunction. Whether these changes eventually resolve remains unclear. This study assessed left and right ventricular structure and function, and ventricular-arterial interaction in 15 women 11 years after a pregnancy with PE and 16 matched control subjects with a normal pregnancy. We found normal left and right ventricular dimensions, systolic function, and global left ventricular strain, with no differences between the groups. In addition, indices of diastolic function, left and right atrial size, and amino-terminal pro-brain natriuretic peptide were normal and did not differ between the groups. Women with a previous PE had impaired night/day ratios for systolic and diastolic ambulatory blood pressure. However, indices of aortic stiffness or ventricular-arterial coupling did not differ between the groups. In conclusion, we could not demonstrate remaining alterations in systolic or diastolic left or right ventricular function, or in ventricular-arterial interaction in women 11 years after PE. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

A compact centrifugal blood pump for extracorporeal circulation: design and performance.

PubMed

Tanaka, S; Yamamoto, S; Yamakoshi, K; Kamiya, A

1987-08-01

A new compact centrifugal blood pump driven by a miniature DC servomotor has been designed for use for short-term extra corporeal and cardiac-assisted circulation. The impeller of the pump was connected directly to the motor by using a simple-gear coupling. The shaft for the impeller was sealed from blood by both a V-ring and a seal bearing. Either pulsatile or nonpusatile flow was produced by controlling the current supply to the motor. The pump characteristics and the degree of hemolysis were evaluated with regard to the configuration of the impeller with a 38-mm outer diameter in vitro tests; the impeller having the blade angles at the inlet of 20 deg and at the outlet of 50 deg was the most appropriate as a blood pump. The performance in an operation, hemolysis and thrombus formation in the pump were assessed by a left ventricular bypass experiment in dogs. It was suggested by this study that this prototype pump appears promising for use not only in animal experiments but also in clinical application.

A Passively-Suspended Tesla Pump Left Ventricular Assist Device

PubMed Central

Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

2009-01-01

The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

Rate-dependent Ca2+ signalling underlying the force-frequency response in rat ventricular myocytes: a coupled electromechanical modeling study

PubMed Central

2013-01-01

Background Rate-dependent effects on the Ca2+ sub-system in a rat ventricular myocyte are investigated. Here, we employ a deterministic mathematical model describing various Ca2+ signalling pathways under voltage clamp (VC) conditions, to better understand the important role of calmodulin (CaM) in modulating the key control variables Ca2+/calmodulin-dependent protein kinase-II (CaMKII), calcineurin (CaN), and cyclic adenosine monophosphate (cAMP) as they affect various intracellular targets. In particular, we study the frequency dependence of the peak force generated by the myofilaments, the force-frequency response (FFR). Methods Our cell model incorporates frequency-dependent CaM-mediated spatially heterogenous interaction of CaMKII and CaN with their principal targets (dihydropyridine (DHPR) and ryanodine (RyR) receptors and the SERCA pump). It also accounts for the rate-dependent effects of phospholamban (PLB) on the SERCA pump; the rate-dependent role of cAMP in up-regulation of the L-type Ca2+ channel (ICa,L); and the enhancement in SERCA pump activity via phosphorylation of PLB. Results Our model reproduces positive peak FFR observed in rat ventricular myocytes during voltage-clamp studies both in the presence/absence of cAMP mediated β-adrenergic stimulation. This study provides quantitative insight into the rate-dependence of Ca2+-induced Ca2+-release (CICR) by investigating the frequency-dependence of the trigger current (ICa,L) and RyR-release. It also highlights the relative role of the sodium-calcium exchanger (NCX) and the SERCA pump at higher frequencies, as well as the rate-dependence of sarcoplasmic reticulum (SR) Ca2+ content. A rigorous Ca2+ balance imposed on our investigation of these Ca2+ signalling pathways clarifies their individual roles. Here, we present a coupled electromechanical study emphasizing the rate-dependence of isometric force developed and also investigate the temperature-dependence of FFR. Conclusions Our model provides mechanistic biophysically based explanations for the rate-dependence of CICR, generating useful and testable hypotheses. Although rat ventricular myocytes exhibit a positive peak FFR in the presence/absence of beta-adrenergic stimulation, they show a characteristic increase in the positive slope in FFR due to the presence of Norepinephrine or Isoproterenol. Our study identifies cAMP-mediated stimulation, and rate-dependent CaMKII-mediated up-regulation of ICa,L as the key mechanisms underlying the aforementioned positive FFR. PMID:24020888

Is plasma N-BNP a good indicator of the functional reserve of failing hearts? The FRESH-BNP study.

PubMed

Williams, Simon G; Ng, Leong L; O'Brien, Russell J; Taylor, Steve; Wright, D Jay; Tan, Lip-Bun

2004-12-01

Whether plasma N-terminal brain natriuretic peptide (N-BNP) is useful in the diagnosis of heart failure (HF) depends traditionally on whether it is as good as the putative 'gold-standard', left ventricular ejection fraction (LVEF), in indicating cardiac dysfunction. However, since HF is primarily an impairment of function of the cardiac pump, we explored the relationship between N-BNP and direct and indirect indicators of cardiac pump dysfunction. Eighty-six HF patients (mean age 56 years) with a range of LVEF's (mean 36.9+/-15.2%, range 15-66%) and 10 age-matched healthy controls were recruited into the study and had resting N-BNP measured. Cardiopulmonary exercise testing was performed to assess peak oxygen consumption (Vo(2)). A subgroup of 23 subjects underwent further exercise haemodynamic assessment to evaluate peak cardiac power output (CPO). The CHF group had significantly higher N-BNP (median [interquartile range]) levels (299 [705] fmol/ml) than the control group (7 [51] fmol/ml, P<0.005). Significant correlations between N-BNP and peak Vo(2), and N-BNP and peak CPO were observed (R> or =0.5, P<0.005). Although significant correlation was observed between N-BNP and LVEF (R=0.34, P=0.01), the correlations between LVEF and peak Vo(2) or peak CPO (all R<0.3, P>0.3) were not significant. Multivariate analysis identified plasma N-BNP and NYHA class, but not LVEF, as independent predictors of peak Vo(2). We have found that N-BNP was surprisingly good as a simple indicator of cardiac pump dysfunction. Since heart failure is an inadequacy of function, these results strongly support the notion that N-BNP is a useful blood test in estimating the extent of cardiac pump dysfunction and helpful in establishing positive diagnosis of heart failure.

Measurement of blood flow from an assist ventricle by computation of pneumatic driving parameters.

PubMed

Qian, K X

1992-03-01

The measurement of blood flow from an assist ventricle is important but sometimes difficult in artificial heart experiments. Along with the development of a pneumatic cylinder-piston driver coupled with a ventricular assist device, a simplified method for measuring pump flow was established. From driving parameters such as the piston (or cylinder) displacement and air pressure, the pump flow could be calculated by the use of the equation of state for an ideal gas. The results of this method are broadly in agreement with electromagnetic and Doppler measurements.

[The reasonable use of right ventricular protection strategy in right ventricular outflow tract reconstruction].

PubMed

Zhang, Y; Yuan, H Y; Liu, X B; Wen, S S; Xu, G; Cui, H J; Zhuang, J; Chen, J M

2018-06-01

As a result of right ventricular outflow tract reconstruction, which is the important and basic step of complex cardiac surgery, the blood flow of right ventricular outflow tract is unobstructed, while pulmonary valve regurgitation and right heart dysfunction could be happened. These problems are often ignored in early days, more and more cases of right heart dysfunction need clinical intervention, which is quite difficult and less effective. How to protect effectively the right ventricular function is the focus. At present main methods to protect the right ventricular function include trying to avoid or reduce length of right ventricular incision, reserving or rebuilding the function of the pulmonary valve, using growth potential material for surgery. The protection of the right ventricular function is a systemic project, it involves many aspects, single measures is difficult to provide complete protection, only the comprehensive use of various protection strategy, can help to improve the long-term prognosis.

Ultracompact, completely implantable permanent use electromechanical ventricular assist device and total artificial heart.

PubMed

Honda, N; Inamoto, T; Nogawa, M; Takatani, S

1999-03-01

An ultracompact, completely implantable permanent use electromechanical ventricular assist device (VAD) and total artificial heart (TAH) intended for 50-60 kg size patients have been developed. The TAH and VAD share a miniature electromechanical actuator that comprises a DC brushless motor and a planetary roller screw. The rotational force of the motor is converted into the rectilinear force of the roller screw to actuate the blood pump. The TAH is a one piece design with left and right pusher plate type blood pumps sandwiching an electromechanical actuator. The VAD is one half of the TAH with the same actuator but a different pump housing and a backplate. The blood contacting surfaces, including those of the flexing diaphragm and pump housing, of both the VAD and TAH were made of biocompatible polyurethane. The diameter, thickness, volume, and weight of the VAD are 90 mm, 56 mm, 285 cc, and 380 g, respectively, while those of the TAH are 90 mm, 73 mm, 400 cc, and 440 g, respectively. The design stroke volume of both the VAD and TAH is 60 cc with the stroke length being 12 mm. The stroke length and motor speed are controlled solely based on the commutation signals of the motor. An in vitro study revealed that a maximum pump flow of 7.5 L/min can be obtained with a pump rate of 140 bpm against a mean afterload of 100 mm Hg. The power requirement ranged from 4 to 6 W to deliver a 4-5 L/min flow against a 100 mm Hg afterload with the electrical-to-hydraulic efficiency being 19-20%. Our VAD and TAH are the smallest of the currently available devices and suitable for bridge to transplant application as well as for permanent circulatory support of 50-60 kg size patients.

Identification and Management of Pump Thrombus in the HeartWare Left Ventricular Assist Device System: A Novel Approach Using Log File Analysis.

PubMed

Jorde, Ulrich P; Aaronson, Keith D; Najjar, Samer S; Pagani, Francis D; Hayward, Christopher; Zimpfer, Daniel; Schlöglhofer, Thomas; Pham, Duc T; Goldstein, Daniel J; Leadley, Katrin; Chow, Ming-Jay; Brown, Michael C; Uriel, Nir

2015-11-01

The study sought to characterize patterns in the HeartWare (HeartWare Inc., Framingham, Massachusetts) ventricular assist device (HVAD) log files associated with successful medical treatment of device thrombosis. Device thrombosis is a serious adverse event for mechanical circulatory support devices and is often preceded by increased power consumption. Log files of the pump power are easily accessible on the bedside monitor of HVAD patients and may allow early diagnosis of device thrombosis. Furthermore, analysis of the log files may be able to predict the success rate of thrombolysis or the need for pump exchange. The log files of 15 ADVANCE trial patients (algorithm derivation cohort) with 16 pump thrombus events treated with tissue plasminogen activator (tPA) were assessed for changes in the absolute and rate of increase in power consumption. Successful thrombolysis was defined as a clinical resolution of pump thrombus including normalization of power consumption and improvement in biochemical markers of hemolysis. Significant differences in log file patterns between successful and unsuccessful thrombolysis treatments were verified in 43 patients with 53 pump thrombus events implanted outside of clinical trials (validation cohort). The overall success rate of tPA therapy was 57%. Successful treatments had significantly lower measures of percent of expected power (130.9% vs. 196.1%, p = 0.016) and rate of increase in power (0.61 vs. 2.87, p < 0.0001). Medical therapy was successful in 77.7% of the algorithm development cohort and 81.3% of the validation cohort when the rate of power increase and percent of expected power values were <1.25% and 200%, respectively. Log file parameters can potentially predict the likelihood of successful tPA treatments and if validated prospectively, could substantially alter the approach to thrombus management. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Ventricular distension and diastolic coronary blood flow in the anaesthetized dog.

PubMed

Gattullo, D; Linden, R J; Losano, G; Pagliaro, P; Westerhof, N

1993-01-01

There appears to be no agreement as to whether or not an increase in diastolic left ventricular pressure and/or volume can cause a decrease in diastolic coronary blood flow. We investigated the problem in the anaesthetized dog using a flaccid freely distensible latex balloon inserted into the left ventricle with the animal on extracorporeal circulation and the coronary perfusion pressure constant at about 45 mm Hg. Maximal vasodilatation and suppression of autoregulation in coronary vasculature was obtained by the intracoronary infusion of dipyridamole (10-40 mg/h). Ventricular volume was changed in steps of 10 ml from 10 to 70 ml and back to 10 ml, whilst recording coronary blood flow and left ventricular pressure in the left circumflex coronary artery. Over a range of ventricular volumes from 20 to 50 ml and a concomitant rise in diastolic ventricular pressure to about 20 mm Hg there was no change in the diastolic coronary flow. Only when the ventricular volume was more than two times the control value (i.e. exceeded 50 ml) and left ventricular pressure was more than 20 mm Hg, was there a decrease in coronary flow. During the return of the volume to the control level there was a fall in diastolic flow and ventricular contractility with respect to the values obtained when the volume was increased; these two effects were transient lasting less than 10 min. It was not considered that any of the three models of the coronary circulation, waterfall, intramyocardial pump or varying elastance model could explain our results.(ABSTRACT TRUNCATED AT 250 WORDS)

Predicting the risk of sudden cardiac death.

PubMed

Lerma, Claudia; Glass, Leon

2016-05-01

Sudden cardiac death (SCD) is the result of a change of cardiac activity from normal (typically sinus) rhythm to a rhythm that does not pump adequate blood to the brain. The most common rhythms leading to SCD are ventricular tachycardia (VT) or ventricular fibrillation (VF). These result from an accelerated ventricular pacemaker or ventricular reentrant waves. Despite significant efforts to develop accurate predictors for the risk of SCD, current methods for risk stratification still need to be improved. In this article we briefly review current approaches to risk stratification. Then we discuss the mathematical basis for dynamical transitions (called bifurcations) that may lead to VT and VF. One mechanism for transition to VT or VF involves a perturbation by a premature ventricular complex (PVC) during sinus rhythm. We describe the main mechanisms of PVCs (reentry, independent pacemakers and abnormal depolarizations). An emerging approach to risk stratification for SCD involves the development of individualized dynamical models of a patient based on measured anatomy and physiology. Careful analysis and modelling of dynamics of ventricular arrhythmia on an individual basis will be essential in order to improve risk stratification for SCD and to lay a foundation for personalized (precision) medicine in cardiology. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Mechanical Circulatory Support for Advanced Heart Failure: Are We about to Witness a New "Gold Standard"?

PubMed

Capoccia, Massimo

2016-12-12

The impact of left ventricular assist devices (LVADs) for the treatment of advanced heart failure has played a significant role as a bridge to transplant and more recently as a long-term solution for non-eligible candidates. Continuous flow left ventricular assist devices (CF-LVADs), based on axial and centrifugal design, are currently the most popular devices in view of their smaller size, increased reliability and higher durability compared to pulsatile flow left ventricular assist devices (PF-LVADs). The trend towards their use is increasing. Therefore, it has become mandatory to understand the physics and the mathematics behind their mode of operation for appropriate device selection and simulation set up. For this purpose, this review covers some of these aspects. Although very successful and technologically advanced, they have been associated with complications such as pump thrombosis, haemolysis, aortic regurgitation, gastro-intestinal bleeding and arterio-venous malformations. There is perception that the reduced arterial pulsatility may be responsible for these complications. A flow modulation control approach is currently being investigated in order to generate pulsatility in rotary blood pumps. Thrombus formation remains the most feared complication that can affect clinical outcome. The development of a preoperative strategy aimed at the reduction of complications and patient-device suitability may be appropriate. Patient-specific modelling based on 3D reconstruction from CT-scan combined with computational fluid dynamic studies is an attractive solution in order to identify potential areas of stagnation or challenging anatomy that could be addressed to achieve the desired outcome. The HeartMate II (axial) and the HeartWare HVAD (centrifugal) rotary blood pumps have been now used worldwide with proven outcome. The HeartMate III (centrifugal) is now emerging as the new promising device with encouraging preliminary results. There are now enough pumps on the market: it is time to focus on the complications in order to achieve the full potential and selling-point of this type of technology for the treatment of the increasing heart failure patient population.

A modified elastance model to control mock ventricles in real-time: numerical and experimental validation.

PubMed

Colacino, Francesco Maria; Moscato, Francesco; Piedimonte, Fabio; Danieli, Guido; Nicosia, Salvatore; Arabia, Maurizio

2008-01-01

This article describes an elastance-based mock ventricle able to reproduce the correct ventricular pressure-volume relationship and its correct interaction with the hydraulic circuit connected to it. A real-time control of the mock ventricle was obtained by a new left ventricular mathematical model including resistive and inductive terms added to the classical Suga-Sagawa elastance model throughout the whole cardiac cycle. A valved piston pump was used to mimic the left ventricle. The pressure measured into the pump chamber was fed back into the mathematical model and the calculated reference left ventricular volume was used to drive the piston. Results show that the classical model is very sensitive to pressure disturbances, especially during the filling phase, while the modified model is able to filter out the oscillations thus eliminating their detrimental effects. The presented model is thus suitable to control mock ventricles in real-time, where sudden pressure disturbances represent a key issue and are not negligible. This real-time controlled mock ventricle is able to reproduce the elastance mechanism of a natural ventricle by mimicking its preload (mean atrial pressure) and afterload (mean aortic pressure) sensitivity, i.e., the Starling law. Therefore, it can be used for designing and testing cardiovascular prostheses due to its capability to reproduce the correct ventricle-vascular system interaction.

A motor-driven ventricular assist device controlled with an optical encoder system.

PubMed

Nakamura, T; Hayashi, K; Yamane, H

1993-01-01

An electric motor-driven ventricular assist device has been developed for long-term use inside the body. The system is composed of a pusher-plate-type blood pump and an actuator consisting of an electrical motor and a ball screw. Cyclic change of the direction of motor rotation makes a back-and-forth axial movement of the ball screw shaft. The shaft, which is detached from the pump diaphragm, pushes the diaphragm via a pusher plate to eject blood during systole; blood is sucked by the diaphragm resilience during diastole. Using the output signals from a newly designed, incremental-type, miniature optical rotary encoder mounted inside the actuator, the input voltage of the motor is optimally controlled referring to the phase difference between the current position of the moving rotor and the electrical reference signal of the rotation generated by a microprocessor-based controller. In vitro performance tests indicated that the system fulfills required specifications. The maximum efficiency was 11%, which was about twice as high as that obtained with the previous open-loop prototype system. In the air, the surface temperature of the actuator elevated to 20 degrees C above the room temperature. An acute in vivo test showed its feasibility as a left ventricular assist device. Analysis of the energy loss in each component of the system indicated that redesign and precise assembly of the mechanical parts could increase the system efficiency.

Ambient hemolysis and activation of coagulation is different between HeartMate II and HeartWare left ventricular assist devices.

PubMed

Birschmann, Ingvild; Dittrich, Marcus; Eller, Thomas; Wiegmann, Bettina; Reininger, Armin J; Budde, Ulrich; Strüber, Martin

2014-01-01

Thromboembolic and bleeding events in patients with a left ventricular assist device (LVAD) are still a major cause of complications. Therefore, the balance between anti-coagulant and pro-coagulant factors needs to be tightly controlled. The principle hypothesis of this study is that different pump designs may have an effect on hemolysis and activation of the coagulation system. Referring to this, the HeartMate II (HMII; Thoratec Corp, Pleasanton, CA) and the HeartWare HVAD (HeartWare International Inc, Framingham, MA) were investigated. For 20 patients with LVAD support (n = 10 each), plasma coagulation, full blood count, and clinical chemistry parameters were measured. Platelet function was monitored using platelet aggregometry, platelet function analyzer-100 system ( Siemens, Marburg, Germany), vasodilator-stimulated phosphoprotein phosphorylation assay, immature platelet fraction, platelet-derived microparticles, and von Willebrand diagnostic. Acquired von Willebrand syndrome could be detected in all patients. Signs of hemolysis, as measured by lactate dehydrogenase levels (mean, 470 U/liter HMII, 250 U/liter HVAD; p < 0.001), were more pronounced in the HMII patients. In contrast, D-dimer analysis indicated a significantly higher activation of the coagulation system in HVAD patients (mean, 0.94 mg/liter HMII, 2.01 mg/liter HVAD; p < 0.01). The efficacy of anti-platelet therapy using clopidogrel was not sufficient in more than 50% of the patients. Our results support the finding that all patients with rotary blood pumps suffered from von Willebrand syndrome. In addition, a distinct footprint of effects on hemolysis and the coagulation system can be attributed to different devices. As a consequence, the individual status of the coagulation system needs to be controlled in long-term patients. © 2013 Published by International Society for the Heart and Lung Transplantation on behalf of International Society for Heart and Lung Transplantation.

Left and right ventricular hemodynamic forces in healthy volunteers and elite athletes assessed with 4D flow magnetic resonance imaging.

PubMed

Arvidsson, Per M; Töger, Johannes; Carlsson, Marcus; Steding-Ehrenborg, Katarina; Pedrizzetti, Gianni; Heiberg, Einar; Arheden, Håkan

2017-02-01

Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients' forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies. NEW & NOTEWORTHY Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the pulmonary circulation. Force patterns were similar between healthy subjects and athletes, indicating potential utility as a cardiac function biomarker. Copyright © 2017 the American Physiological Society.

Delayed recovery of right ventricular systolic function after repair of long-standing tricuspid regurgitation associated with severe right ventricular failure.

PubMed

Kim, Jong Hun; Kim, Kyung Hwa; Choi, Jong Bum; Kuh, Ja Hong

2016-03-01

After tricuspid valve surgery for long-standing tricuspid regurgitation associated with right ventricular failure, reverse remodelling of the enlarged right ventricle, including recovery of right ventricular systolic function, is unpredictable. We present the case of a 31-year old man with early reduction of dilated right ventricular dimensions and delayed recovery of impaired right ventricular systolic function after valve repair for traumatic tricuspid regurgitation lasting 16 years. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Support with intra-aortic balloon pump vs. Impella2.5® and blood flow to the heart, brain and kidneys - an experimental porcine model of ischaemic heart failure.

PubMed

Møller-Helgestad, Ole K; Poulsen, Christian B; Christiansen, Evald H; Lassen, Jens F; Ravn, Hanne B

2015-01-15

Cardiogenic shock as a complication to an acute myocardial infarction has an unacceptably high death rate that has not changed for the last 15years. Mortality is partly related to organ hypoperfusion and mechanical assist devices are used for the most severe cases but we do not know which assist device is the best option. Therefore, we have investigated how an IABP and an Impella®-pump influenced blood flow to the brain, heart and kidneys, in a closed-chest porcine model of severe left ventricular failure. 13 pigs were anesthetised and left ventricular failure was induced by occluding the proximal LAD for 45min followed by 30min of reperfusion. Blood flow was measured in the carotid artery, the LAD, and the renal artery. The Impella® and IABP were inserted via the femoral arteries, and the two devices were tested individually and combined after induction of heart failure. Carotid- (p=0.01) and renal blood flow (p=0.045) were higher on Impella®-support, compared to no support. None of the devices altered the blood flow in the LAD. Cardiac power output (p<0.005) and left ventricular work (p<0.00) were also higher on Impella®-support compared to no support. Haemodynamics and blood flow to the brain and kidneys were significantly better on Impella®-support, suggesting that the Impella® is superior to the IABP in a state of ischaemia induced left ventricular failure. These data, however, needs to be confirmed in a proper clinical trial with patients in cardiogenic shock. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Ventricular Recovery and Pump Explantation in Patients Supported by Left Ventricular Assist Devices: A Systematic Review.

PubMed

Phan, Kevin; Huo, Ya Ruth; Zhao, Dong Fang; Yan, Tristan D; Tchantchaleishvili, Vakhtang

2016-01-01

Several studies have reported that a portion of patients who exhibit cardiac recovery during left ventricular assist device (LVAD) support can have their device explanted with reasonable long-term survival. The aim of this systematic review is to assess the survival and cardiac function in patients with explanted LVADs from the current literature. Electronic search was performed to identify all studies in English literature assessing LVAD explantation. All identified articles were systematically assessed using the inclusion and exclusion criteria. Selected studies were subjected to quantitative assessment. From 5 electronic databases, 11 studies (213 patients) were included. Pooled mean perioperative mortality rate of those explanted was 9.2% (95% CI, 5.0-14.5%; I = 0). Pooled mean late mortality rate was 15% (95% CI, 9.0-22.1%; I = 31%). The pooled 1, 5, and 10 year survival postexplant was 91, 76, and 65.7%, respectively. Pooled postweaning freedom from heart failure (HF) recurrence reached 81.3%. Subset analysis demonstrated that patients explanted from a continuous-flow LVAD versus pulsatile LVAD had a lower rate of HF recurrence (6.6 vs. 28.3%, p = 0.03) and LVAD reimplantation (7.5 vs. 37%, p = 0.001). Before LVAD explantation, overall mean left ventricular ejection fraction (LVEF) was 49%. Weighted pooled early and late postexplantation mean LVEF was 47.3 and 41.2%, respectively. Late postexplantation LVEF was significantly higher in the continuous-flow versus pulsatile LVAD subgroup (41.5 vs. 24%, p = 0.001). This review shows encouraging safety and 10 year survival outcomes after explantation of LVADs in carefully selected patients, with rates better than expected after a heart transplant. Recovery of the native heart is the most desirable clinical outcome in patients supported with LVADs and should be actively sought.

Superior performance of a paraaortic counterpulsation device compared to the intraaortic balloon pump.

PubMed

Terrovitis, John V; Charitos, Christos E; Tsolakis, Elias J; Dolou, Paraskevi; Pierrakos, Charalampos N; Siafakas, Kostas X; Nanas, John N

2003-12-01

The purpose of this study was to compare the hemodynamic effectiveness of a 30-ml stroke volume paraaortic counterpulsation device (PACD), presenting the advantages of ease of implantation and driving by a standard intraaortic balloon pump (IABP) console (Datascope 96, Datascope Corp., Montvale, NJ, USA) to that of a 40-ml IABP, in the setting of experimental heart failure. In an acute heart failure model, the IABP was placed in the descending aorta and the PACD in the ascending aorta of eight pigs. Both devices were driven by the same system, and hemodynamic measurements were obtained with and without mechanical assistance. The two pumps significantly reduced the systolic and end-diastolic aortic pressures, but the PACD reduced the latter more effectively (42.6 +/- 18.1% vs 11.0 +/- 9.9%, p = 0.0001). Both pumps provided significant aortic diastolic augmentation, but the counterpulsation wave of the PACD was significantly greater (augmentation of 44.8 +/- 22.2% vs 37.6 +/- 15.6%, p = 0.031). Both lowered the end-diastolic left ventricular pressure with a trend toward PACD superiority (24.2 +/- 13.7% vs 19.7 +/- 13.5%, p = 0.064). It is concluded that the PACD, even with smaller stroke volume, is more effective than the IABP. The simplicity of its implantation, together with the ability of the standard IABP consoles to control its function, make it a promising device for mechanical assistance of the failing heart.

Future Prospects for the Total Artificial Heart.

PubMed

Sunagawa, Gengo; Horvath, David J; Karimov, Jamshid H; Moazami, Nader; Fukamachi, Kiyotaka

2016-01-01

A total artificial heart (TAH) is the sole remaining option for patients with biventricular failure who cannot be rescued by left ventricular assist devices (LVADs) alone. However, the pulsatile TAH in clinical use today has limitations: large pump size, unknown durability, required complex anticoagulation regimen, and association with significant postsurgical complications. That pump is noisy; its large pneumatic driving lines traverse the body, with bulky external components for its drivers. Continuous-flow pumps, which caused a paradigm shift in the LVAD field, have already contributed to the rapidly evolving development of TAHs. Novel continuous-flow TAHs are only in preclinical testing or developmental stages. We here review the current state of TAHs, with recommended requirements for the TAH of the future.

Thoracic Epidural Anesthesia Reduces Right Ventricular Systolic Function With Maintained Ventricular-Pulmonary Coupling.

PubMed

Wink, Jeroen; de Wilde, Rob B P; Wouters, Patrick F; van Dorp, Eveline L A; Veering, Bernadette Th; Versteegh, Michel I M; Aarts, Leon P H J; Steendijk, Paul

2016-10-18

Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia may affect right ventricular function and interfere with the coupling between right ventricular function and right ventricular afterload. Our main objectives were to study the effects of thoracic epidural anesthesia on right ventricular function and ventricular-pulmonary coupling. In 10 patients scheduled for lung resection, right ventricular function and its response to increased afterload, induced by temporary, unilateral clamping of the pulmonary artery, was tested before and after induction of thoracic epidural anesthesia using combined pressure-conductance catheters. Thoracic epidural anesthesia resulted in a significant decrease in right ventricular contractility (ΔESV 25 : +25.5 mL, P=0.0003; ΔEes: -0.025 mm Hg/mL, P=0.04). Stroke work, dP/dt MAX , and ejection fraction showed a similar decrease in systolic function (all P<0.05). A concomitant decrease in effective arterial elastance (ΔEa: -0.094 mm Hg/mL, P=0.004) yielded unchanged ventricular-pulmonary coupling. Cardiac output, systemic vascular resistance, and mean arterial blood pressure were unchanged. Clamping of the pulmonary artery significantly increased afterload (ΔEa: +0.226 mm Hg/mL, P<0.001). In response, right ventricular contractility increased (ΔESV 25 : -26.6 mL, P=0.0002; ΔEes: +0.034 mm Hg/mL, P=0.008), but ventricular-pulmonary coupling decreased (Δ(Ees/Ea) = -0.153, P<0.0001). None of the measured indices showed significant interactive effects, indicating that the effects of increased afterload were the same before and after thoracic epidural anesthesia. Thoracic epidural anesthesia impairs right ventricular contractility but does not inhibit the native positive inotropic response of the right ventricle to increased afterload. Right ventricular-pulmonary arterial coupling was decreased with increased afterload but not affected by the induction of thoracic epidural anesthesia. URL: http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2844. Unique identifier: NTR2844. © 2016 American Heart Association, Inc.

The MVAD pump: motor stator core loss characterization.

PubMed

Mesa, Kelly J; Ferreira, Antonio; Castillo, Samir; Reyes, Carlos; Wolman, Justin; Casas, Fernando

2015-01-01

Investigation of the miniature ventricular assist device (MVAD) pump motor stator core loss behavior was conducted. During operation, the ferromagnetic core in the pump's motor is magnetized by alternating magnetic fields, which, in turn, create intrinsic energy losses in the core material; these losses are known as core losses. A core loss fixture and a method to characterize the magnetic behavior of the MVAD pump stator over a range of frequencies were developed. The MVAD pump motor design features a three phase brushless DC stator with ferromagnetic laminations and copper wire windings arranged in a six slot configuration. The stator's magnetic behavior is important because its core magnetic losses impact pump system efficiency. A system to measure the core loss of MVAD pump stators was developed using a custom core loss fixture consisting of 16 copper wire turns wound in a closed loop geometry bundle; the stator under test was then placed within this bundle. The instrumentation consisted of a signal generator, a power amplifier, and a power analyzer. Power analyzer parameters of current, voltage, and power were collected for several runs with a sinusoidal frequency sweep of 0 to 50 kHz; data were collected for the fixture with and without stators. The magnetic losses inherent to the fixture were characterized independently as a baseline presenting a flat frequency response. The core loss power measurements of individual stators yielded a characteristic bandpass frequency response morphology with a peak core loss found around 2.3 to 2.5 kHz. In conclusion, this method could be used to describe the transfer function of the stator's core magnetic behavior. It also has the potential to be used for future motor evaluation and for investigation of core loss performance variability between different stators during manufacturing operations. Investigational device. Limited by United States law to investigational use.

Pulmonary hemodynamics and gas exchange in off pump coronary artery bypass grafting.

PubMed

Vedin, Jenny; Jensen, Ulf; Ericsson, Anders; Samuelsson, Sten; Vaage, Jarle

2005-10-01

To investigate the influence of cardiopulmonary bypass on pulmonary hemodynamics and gas exchange. Low risk patients admitted for elective coronary artery bypass grafting were randomized to either on (n=25) or off pump (n=25) surgery. Central hemodynamics, gas exchange, and venous admixture were studied during and up to 20 h after surgery. There was no difference in pulmonary vascular resistance index (P=0.16), right ventricular stroke work index (P>0.2), mean pulmonary artery pressure (P>0.2) or pulmonary capillary wedge pressure (P>0.2) between groups. Soon after surgery there was a tendency towards higher cardiac index (P=0.07) in the off pump group. Arterial oxygen tension (P>0.2), hematocrit (P>0.2), venous admixture (P>0.2), and arterial-venous oxygen content difference (P=0.12) did not differ between groups. This prospective, randomized study showed no difference in pulmonary hemodynamics, pulmonary gas exchange, and venous admixture, in low risk patients undergoing off pump compared to on pump coronary artery bypass surgery.

Atrial Function after the Atrial Switch Operation for Transposition of the Great Arteries: Comparison with Arterial Switch and Normals by Cardiovascular Magnetic Resonance.

PubMed

Franzoso, Francesca D; Wohlmuth, Christoph; Greutmann, Matthias; Kellenberger, Christian J; Oxenius, Angela; Voser, Eva M; Valsangiacomo Buechel, Emanuela R

2016-09-01

The atria serve as reservoir, conduit, and active pump for ventricular filling. The performance of the atrial baffles after atrial switch repair for transposition of the great arteries may be abnormal and impact the function of the systemic right ventricle. We sought to assess atrial function in patients after atrial repair in comparison to patients after arterial switch repair (ASO) and to controls. Using magnetic resonance imaging, atrial volumes and functional parameters were measured in 17 patients after atrial switch repair, 9 patients after ASO and 10 healthy subjects. After the atrial switch operation, the maximum volume of the pulmonary venous atrium was significantly enlarged, but not of the systemic venous atrium. In both patients groups, independently from the surgical technique used, the minimum atrial volumes were elevated, which resulted in a decreased total empting fraction compared with controls (P < .01). The passive empting volume was diminished for right atrium, but elevated for left atrium after atrial switch and normal for left atrium after ASO; however, the passive empting fraction was diminished for both right atrium and left atrium after both operations (P < .01). The active empting volume was the most affected parameter in both atria and both groups and active empting fractions were highly significantly reduced compared with controls. Atrial function is abnormal in all patients, after atrial switch and ASO repair. The cyclic volume changes, that is, atrial filling and empting, are reduced when compared with normal subjects. Thus, the atria have lost part of their capacity to convert continuous venous flow into a pulsatile ventricular filling. The function of the pulmonary venous atrium, acting as preload for the systemic right ventricle, after atrial switch is altered the most. © 2015 Wiley Periodicals, Inc.

Gene Therapy With Angiotensin-(1-9) Preserves Left Ventricular Systolic Function After Myocardial Infarction.

PubMed

Fattah, Caroline; Nather, Katrin; McCarroll, Charlotte S; Hortigon-Vinagre, Maria P; Zamora, Victor; Flores-Munoz, Monica; McArthur, Lisa; Zentilin, Lorena; Giacca, Mauro; Touyz, Rhian M; Smith, Godfrey L; Loughrey, Christopher M; Nicklin, Stuart A

2016-12-20

Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin-angiotensin-aldosterone system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic mini-pump. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI). The authors evaluated effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post-infarction. C57BL/6 mice underwent permanent left anterior descending coronary artery ligation and cardiac function was assessed using echocardiography for 8 weeks followed by a terminal measurement of left ventricular pressure volume loops. Ang-(1-9) was delivered by adeno-associated viral vector via single tail vein injection immediately following induction of MI. Direct effects of Ang-(1-9) on cardiomyocyte excitation/contraction coupling and cardiac contraction were evaluated in isolated mouse and human cardiomyocytes and in an ex vivo Langendorff-perfused whole-heart model. Gene delivery of Ang-(1-9) reduced sudden cardiac death post-MI. Pressure volume measurements revealed complete restoration of end-systolic pressure, ejection fraction, end-systolic volume, and the end-diastolic pressure volume relationship by Ang-(1-9) treatment. Stroke volume and cardiac output were significantly increased versus sham. Histological analysis revealed only mild effects on cardiac hypertrophy and fibrosis, but a significant increase in scar thickness. Direct assessment of Ang-(1-9) on isolated cardiomyocytes demonstrated a positive inotropic effect via increasing calcium transient amplitude and contractility. Ang-(1-9) increased contraction in the Langendorff model through a protein kinase A-dependent mechanism. Our novel findings showed that Ang-(1-9) gene therapy preserved left ventricular systolic function post-MI, restoring cardiac function. Furthermore, Ang-(1-9) directly affected cardiomyocyte calcium handling through a protein kinase A-dependent mechanism. These data emphasized Ang-(1-9) gene therapy as a potential new strategy in the context of MI. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Functionally univentricular heart and the fontan operation: lessons learned about patterns of practice and outcomes from the congenital heart surgery databases of the European association for cardio-thoracic surgery and the society of thoracic surgeons.

PubMed

Jacobs, Jeffrey Phillip; Maruszewski, Bohdan

2013-10-01

"The term "functionally univentricular heart" describes a spectrum of congenital cardiovascular malformations in which the ventricular mass may not readily lend itself to partitioning that commits one ventricular pump to the systemic circulation and another to the pulmonary circulation." The purpose of this article is to review patterns of practice and outcomes in the Congenital Heart Surgery Databases (CHSDBs) of the European Association for Cardio-Thoracic Surgery (EACTS) and the Society of Thoracic Surgeons (STS) in patients with functionally univentricular hearts undergoing the Fontan operation. We examined all index operations performed on patients with functionally univentricular hearts in the EACTS and STS-CHSDBs over 4 years from 2007 to 2010, inclusive. The most common diagnostic categories are hypoplastic left heart syndrome, tricuspid atresia, and double inlet left ventricle. The Fontan operation makes up 3.2% of all cardiac operations in the EACTS and STS-CHSDBs over 4 years from 2007 to 2010, inclusive. Of all the patients undergoing a Fontan procedure, 65.1% had an extracardiac Fontan, 21.5% had a lateral tunnel, and 5.8% had a Fontan revision or conversion (Re-do Fontan). In operations where fenestration status is known, 68.5% of the Fontan operations were fenestrated. During the four years of this analysis, only 5 patients had ventricular septation. Exclusive of Fontan revision or conversion (Re-do Fontan), all remaining Fontan operations had a discharge mortality of 2.3%. Fontan revision or conversion (Re-do Fontan) had a discharge mortality of 12.8%. The STS database is largest CHSDB in North America. The EACTS database is largest CHSDB in Europe. This review of data from EACTS and STS allows for unique documentation of practice patterns and outcomes. From this analysis, it is clear that patients with functionally univentricular hearts present a challenging problem; however, exclusive of Fontan revision or conversion (Re-do Fontan), the Fontan operation has a discharge mortality of 2.3%.

Comparative study of diastolic filling under varying left ventricular wall stiffness

NASA Astrophysics Data System (ADS)

Mekala, Pritam; Santhanakrishnan, Arvind

2014-11-01

Pathological remodeling of the human cardiac left ventricle (LV) is observed in hypertensive heart failure as a result of pressure overload. Myocardial stiffening occurs in these patients prior to chronic maladaptive changes, resulting in increased LV wall stiffness. The goal of this study was to investigate the change in intraventricular filling fluid dynamics inside a physical model of the LV as a function of wall stiffness. Three LV models of varying wall stiffness were incorporated into an in vitro flow circuit driven by a programmable piston pump. Windkessel elements were used to tune the inflow and systemic pressure in the model with least stiffness to match healthy conditions. Models with stiffer walls were comparatively tested maintaining circuit compliance, resistance and pump amplitude constant. 2D phase-locked PIV measurements along the central plane showed that with increase in wall stiffness, the peak velocity and cardiac output inside the LV decreased. Further, inflow vortex ring propagation toward the LV apex was reduced with increasing stiffness. The above findings indicate the importance of considering LV wall relaxation characteristics in pathological studies of filling fluid dynamics.

The Future of Adult Cardiac Assist Devices: Novel Systems and Mechanical Circulatory Support Strategies

PubMed Central

Bartoli, Carlo R.; Dowling, Robert D.

2011-01-01

Synopsis The recent, widespread success of mechanical circulatory support has ushered in a new era of cardiovascular medicine in which numerous implantable devices exist to treat advanced heart failure. As cardiac assist devices gain prevalence in the clinical management of cardiovascular disease, it is increasingly important to raise awareness of novel device systems, the unique mechanisms by which they function, and implications for patient management. In this article, we present state-of-the-art devices that are currently under development or in clinical trials. Devices are categorized as Standard Full-Support (HeartMate III, CorAide, Evaheart LVAS), Less-Invasive Full-Support (MVAD), Partial-Support (CircuLite Synergy Pocket Micro-Pump, Reitan Catheter Pump, Procyrion CAD, C-Pulse, Symphony Counterpulsation Device) Right Ventricular Assist Device (RVAD; DexAide, Impella RD Recover, Impella RP), and Total Artificial Heart (TAH; CardioWest, AbioCor II, Continuous-Flow TAH, Continuous-Flow BiVAD). Implantation strategy, mechanism of action, durability, efficacy, hemocompatibility, and human factors such as quality of life during device support are considered. The feasibility of novel strategies for unloading the failing heart is examined. PMID:22062206

A New Parameter for Cardiac Efficiency Analysis

NASA Astrophysics Data System (ADS)

Borazjani, Iman; Rajan, Navaneetha Krishnan; Song, Zeying; Hoffmann, Kenneth; MacMahon, Eileen; Belohlavek, Marek

2014-11-01

Detecting and evaluating a heart with suboptimal pumping efficiency is a significant clinical goal. However, the routine parameters such as ejection fraction, quantified with current non-invasive techniques are not predictive of heart disease prognosis. Furthermore, they only represent left-ventricular (LV) ejection function and not the efficiency, which might be affected before apparent changes in the function. We propose a new parameter, called the hemodynamic efficiency (H-efficiency) and defined as the ratio of the useful to total power, for cardiac efficiency analysis. Our results indicate that the change in the shape/motion of the LV will change the pumping efficiency of the LV even if the ejection fraction is kept constant at 55% (normal value), i.e., H-efficiency can be used for suboptimal cardiac performance diagnosis. To apply H-efficiency on a patient-specific basis, we are developing a system that combines echocardiography (echo) and computational fluid dynamics (CFD) to provide the 3D pressure and velocity field to directly calculate the H-efficiency parameter. Because the method is based on clinically used 2D echo, which has faster acquisition time and lower cost relative to other imaging techniques, it can have a significant impact on a large number of patients. This work is partly supported by the American Heart Association.

Cardiac function in children with premature ventricular contractions: the effect of omega-3 polyunsaturated fatty acid supplementation.

PubMed

Oner, Taliha; Ozdemir, Rahmi; Doksöz, Onder; Genc, Dildar B; Guven, Baris; Demirpence, Savas; Yilmazer, Murat M; Yozgat, Yilmaz; Mese, Timur; Tavli, Vedide

2018-07-01

Premature ventricular contractions are accepted as benign in structurally normal hearts. However, reversible cardiomyopathy can sometimes develop. Omega-3 polyunsaturated fatty acids have anti-arrhythmic properties in animals and humans.AimWe evaluated left ventricular function in children with premature ventricular contractions with normal cardiac anatomy and assessed the impact of omega-3 fatty acid supplementation on left ventricular function in a prospective trial. A total of 25 patients with premature ventricular contraction, with more than 2% premature ventricular contractions on 24-hour Holter electrocardiography, and 30 healthy patients were included into study. All patients underwent electrocardiography, left ventricular M-mode echocardiography, and myocardial performance index testing. Patients with premature ventricular contraction were given omega-3 fatty acids at a dose of 1 g/day for 3 months, and control echocardiography and 24-hour Holter electrocardiography were performed. Neither placebo nor omega-3 fatty acids were given to the control group. Compared with the values of the control group, the patients with premature ventricular contraction had significantly lower fractional shortening. The myocardial performance index decreased markedly in the patient groups. The mean heart rate and mean premature ventricular contraction percentage of Group 2 significantly decreased in comparison with their baseline values after the omega-3 supplementation. In conclusion, premature ventricular contractions can lead to systolic cardiac dysfunction in children. Omega-3 supplementation may improve cardiac function in children with premature ventricular contractions. This is the first study conducted in children to investigate the possible role of omega-3 fatty acid supplementation on treatment of premature ventricular contractions.

[Ventricular tachycardia in a patient with rate-responsive cardiac pacemaker].

PubMed

Himbert, C; Lascault, G; Tonet, J; Coutte, R; Busquet, P; Frank, R; Grosgogeat, Y

1992-11-01

The authors report a case of syncopal ventricular tachycardia in a patient with a respiratory-dependent rate responsive pacemaker, followed-up for valvular heart disease with severe left ventricular dysfunction and sustained atrial and ventricular arrhythmias. The introduction of low dose betablocker therapy with reinforcement of the treatment of cardiac failure controlled the ventricular arrhythmia, after suppression of the data responsive function had been shown to be ineffective. The authors discuss the role of the rate responsive function in the triggering of the ventricular tachycardias.

Development of a radial ventricular assist device using numerical predictions and experimental haemolysis.

PubMed

Carswell, Dave; Hilton, Andy; Chan, Chris; McBride, Diane; Croft, Nick; Slone, Avril; Cross, Mark; Foster, Graham

2013-08-01

The objective of this study was to demonstrate the potential of Computational Fluid Dynamics (CFD) simulations in predicting the levels of haemolysis in ventricular assist devices (VADs). Three different prototypes of a radial flow VAD have been examined experimentally and computationally using CFD modelling to assess device haemolysis. Numerical computations of the flow field were computed using a CFD model developed with the use of the commercial software Ansys CFX 13 and a set of custom haemolysis analysis tools. Experimental values for the Normalised Index of Haemolysis (NIH) have been calculated as 0.020 g/100 L, 0.014 g/100 L and 0.0042 g/100 L for the three designs. Numerical analysis predicts an NIH of 0.021 g/100 L, 0.017 g/100 L and 0.0057 g/100 L, respectively. The actual differences between experimental and numerical results vary between 0.0012 and 0.003 g/100 L, with a variation of 5% for Pump 1 and slightly larger percentage differences for the other pumps. The work detailed herein demonstrates how CFD simulation and, more importantly, the numerical prediction of haemolysis may be used as an effective tool in order to help the designers of VADs manage the flow paths within pumps resulting in a less haemolytic device. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Magnetic design for the PediaFlow ventricular assist device.

PubMed

Noh, Myounggyu D; Antaki, James F; Ricci, Michael; Gardiner, Jeff; Paden, Dave; Wu, Jingchun; Prem, Ed; Borovetz, Harvey; Paden, Bradley E

2008-02-01

This article describes a design process for a new pediatric ventricular assist device, the PediaFlow. The pump is embodied in a magnetically levitated turbodynamic design that was developed explicitly based on the requirements for chronic support of infants and small children. The procedure entailed the consideration of multiple pump topologies, from which an axial mixed-flow configuration was chosen for further development. The magnetic design includes permanent-magnet (PM) passive bearings for radial support of the rotor, an actively controlled thrust actuator for axial support, and a brushless direct current (DC) motor for rotation. These components are closely coupled both geometrically and magnetically, and were therefore optimized in parallel, using electromagnetic, rotordynamic models and fluid models, and in consideration of hydrodynamic requirements. Multiple design objectives were considered, including efficiency, size, and margin between critical speeds to operating speed. The former depends upon the radial and yaw stiffnesses of the PM bearings. Analytical expressions for the stiffnesses were derived and verified through finite element analysis (FEA). A toroidally wound motor was designed for high efficiency and minimal additional negative radial stiffness. The design process relies heavily on optimization at the component level and system level. The results of this preliminary design optimization yielded a pump design with an overall stability margin of 15%, based on a pressure rise of 100 mm Hg at 0.5 lpm running at 16,000 rpm.

The helical ventricular myocardial band: global, three-dimensional, functional architecture of the ventricular myocardium.

PubMed

Kocica, Mladen J; Corno, Antonio F; Carreras-Costa, Francesc; Ballester-Rodes, Manel; Moghbel, Mark C; Cueva, Clotario N C; Lackovic, Vesna; Kanjuh, Vladimir I; Torrent-Guasp, Francisco

2006-04-01

We are currently witnessing the advent of new diagnostic tools and therapies for heart diseases, but, without serious scientific consensus on fundamental questions about normal and diseased heart structure and function. During the last decade, three successive, international, multidisciplinary symposia were organized in order to setup fundamental research principles, which would allow us to make a significant step forward in understanding heart structure and function. Helical ventricular myocardial band of Torrent-Guasp is the revolutionary new concept in understanding global, three-dimensional, functional architecture of the ventricular myocardium. This concept defines the principal, cumulative vectors, integrating the tissue architecture (i.e. form) and net forces developed (i.e. function) within the ventricular mass. Here we expose the compendium of Torrent-Guasp's half-century long functional anatomical investigations in the light of ongoing efforts to define the integrative approach, which would lead to new understanding of the ventricular form and function by linking across multiple scales of biological organization, as defined in ongoing Physiome project. Helical ventricular myocardial band of Torrent-Guasp may also, hopefully, allow overcoming some difficulties encountered in contemporary efforts to create a comprehensive mathematical model of the heart.

The CentriMag: a new optimized centrifugal blood pump with levitating impeller.

PubMed

Mueller, Juerg Peter; Kuenzli, Andreas; Reuthebuch, Oliver; Dasse, Kurt; Kent, Stella; Zuend, Gregor; Turina, Marko Ivan; Lachat, Mario Louis

2004-01-01

Blood pumps are routinely used for circulatory and pulmonary support. However, blood trauma and pump failure remain severe drawbacks of currently available pump models. This study evaluated the first clinical application of a new, totally bearingless centrifugal blood pump (CentriMag). A centrifugal pump consisting of an electromagnetic suspended impeller was used as a blood pump during beating-heart coronary artery bypass grafting in 11 patients (mean weight, 77.4 kg). Heparin in a bolus of 150 IU/kg body weight was administered, and activated clotting time was maintained at approximately 180 to 250 seconds during extracorporeal circulation. Pump-induced blood trauma was evaluated by measurement of plasma free hemoglobin (PFH), lactate dehydrogenase (LDH), hematocrit, total bilirubin, and platelet levels. Mean pump flow was 3.3 +/- 0.62 L/min, and mean pressure gradient through the oxygenator was 69 +/- 4 mm Hg. No pump dysfunction occurred during a mean application time of 105 +/- 26 minutes. Inspection of the pump housings showed no internal thrombus formation despite low-dose heparinization. Only slight hemolysis was observed with a mean PFH level of 1.96 micromol/L; LDH, 460 U/L; hematocrit, 33%; total bilirubin, 25 micromol/L; and platelets, 191 x 10(3)/microL. The bearingless CentriMag blood pump is a safe and reliable new device that produces only minimal hemolysis. It seems to be suited for long-term evaluation as a blood pump for extracorporeal membrane oxygenation or as ventricular assist device.

Left Atrial trajectory impairment in Hypertrophic Cardiomyopathy disclosed by Geometric Morphometrics and Parallel Transport

NASA Astrophysics Data System (ADS)

Piras, Paolo; Torromeo, Concetta; Re, Federica; Evangelista, Antonietta; Gabriele, Stefano; Esposito, Giuseppe; Nardinocchi, Paola; Teresi, Luciano; Madeo, Andrea; Chialastri, Claudia; Schiariti, Michele; Varano, Valerio; Uguccioni, Massimo; Puddu, Paolo E.

2016-10-01

The analysis of full Left Atrium (LA) deformation and whole LA deformational trajectory in time has been poorly investigated and, to the best of our knowledge, seldom discussed in patients with Hypertrophic Cardiomyopathy. Therefore, we considered 22 patients with Hypertrophic Cardiomyopathy (HCM) and 46 healthy subjects, investigated them by three-dimensional Speckle Tracking Echocardiography, and studied the derived landmark clouds via Geometric Morphometrics with Parallel Transport. Trajectory shape and trajectory size were different in Controls versus HCM and their classification powers had high AUC (Area Under the Receiving Operator Characteristic Curve) and accuracy. The two trajectories were much different at the transition between LA conduit and booster pump functions. Full shape and deformation analyses with trajectory analysis enabled a straightforward perception of pathophysiological consequences of HCM condition on LA functioning. It might be worthwhile to apply these techniques to look for novel pathophysiological approaches that may better define atrio-ventricular interaction.

Outflow monitoring of a pneumatic ventricular assist device using external pressure sensors.

PubMed

Kang, Seong Min; Her, Keun; Choi, Seong Wook

2016-08-25

In this study, a new algorithm was developed for estimating the pump outflow of a pneumatic ventricular assist device (p-VAD). The pump outflow estimation algorithm was derived from the ideal gas equation and determined the change in blood-sac volume of a p-VAD using two external pressure sensors. Based on in vitro experiments, the algorithm was revised to consider the effects of structural compliance caused by volume changes in an implanted unit, an air driveline, and the pressure difference between the sensors and the implanted unit. In animal experiments, p-VADs were connected to the left ventricles and the descending aorta of three calves (70-100 kg). Their outflows were estimated using the new algorithm and compared to the results obtained using an ultrasonic blood flow meter (UBF) (TS-410, Transonic Systems Inc., Ithaca, NY, USA). The estimated and measured values had a Pearson's correlation coefficient of 0.864. The pressure sensors were installed at the external controller and connected to the air driveline on the same side as the external actuator, which made the sensors easy to manage.

Development of a compact portable driver for a pneumatic ventricular assist device.

PubMed

Nishinaka, Tomohiro; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Ohnishi, Hiroyuki; Homma, Akihiko; Shioya, Kyoko; Mizuno, Toshihide; Tsukiya, Tomonori; Mushika, Sadahiko; Hashiguchi, Yasuhiro; Suzuki, Akira; Kitamura, Soichiro

2007-01-01

The Toyobo-National Cardiovascular Center pneumatic ventricular assist device (Toyobo-NCVC VAD) is widely used in Japan; however, the current pneumatic drivers have some drawbacks, including their large size, heavy weight, and high power consumption. These issues cause difficulty with mobility and contribute to an unsatisfactory quality of life for patients. Because it is urgently necessary to improve patients' safety and quality of life, we have developed a compact, low-noise, portable VAD driver by utilizing an electrohydraulic actuator consisting of a brushless DC motor and a regenerative pump. This unit can be actuated for as long as 2 h with two rechargeable lightweight batteries as well as with external AC power. It is compact in size (33 x 25 x 43 cm) and light in weight (13 kg), and the unit is carried on a mobile wheeled cart. In vitro testing with a Toyobo-NCVC VAD demonstrated a sufficient pumping capacity of up to 8 l/min. We conclude that this newly-developed compact portable driver can provide a better quality of life and improved safety for patients using protracted pneumatic VAD support.

Temporary Mechanical Circulatory Support: A Review of the Options, Indications, and Outcomes

PubMed Central

Gilotra, Nisha A; Stevens, Gerin R

2014-01-01

Cardiogenic shock remains a challenging disease entity and is associated with significant morbidity and mortality. Temporary mechanical circulatory support (MCS) can be implemented in an acute setting to stabilize acutely ill patients with cardiomyopathy in a variety of clinical situations. Currently, several options exist for temporary MCS. We review the indications, contraindications, clinical applications, and evidences for a variety of temporary circulatory support options, including the intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), CentriMag blood pump, and percutaneous ventricular assist devices (pVADs), specifically the TandemHeart and Impella. PMID:25674024

Patient-Specific Modeling of Interventricular Hemodynamics in Single Ventricle Physiology

NASA Astrophysics Data System (ADS)

Vedula, Vijay; Feinstein, Jeffrey; Marsden, Alison

2016-11-01

Single ventricle (SV) congenital heart defects, in which babies are born with only functional ventricle, lead to significant morbidity and mortality with over 30% of patients developing heart failure prior to adulthood. Newborns with SV physiology typically undergo three palliative surgeries, in which the SV becomes the systemic pumping chamber. Depending on which ventricle performs the systemic function, patients are classified as having either a single left ventricle (SLV) or a single right ventricle (SRV), with SRV patients at higher risk of failure. As the native right ventricles are not designed to meet systemic demands, they undergo remodeling leading to abnormal hemodynamics. The hemodynamic characteristics of SLVs compared with SRVs is not well established. We present a validated computational framework for performing patient-specific modeling of ventricular flows, and apply it across 6 SV patients (3SLV + 3SRV), comparing hemodynamic conditions between the two subgroups. Simulations are performed with a stabilized finite element method coupled with an immersed boundary method for modeling heart valves. We discuss identification of hemodynamic biomarkers of ventricular remodeling for early risk assessment of failure. This research is supported in part by the Stanford Child Health Research Institute and the Stanford NIH-NCATS-CTSA through Grant UL1 TR001085 and due to U.S. National Institute of Health through NIH NHLBI R01 Grants 5R01HL129727-02 and 5R01HL121754-03.

[Clinical characteristics and medium-term prognosis of patients with heart failure and preserved systolic function. Do they differ in systolic dysfunction?].

PubMed

Ojeda, Soledad; Anguita, Manuel; Muñoz, Juan F; Rodríguez, Marcos T; Mesa, Dolores; Franco, Manuel; Ureña, Isabel; Vallés, Federico

2003-11-01

To assess the prevalence, clinical profile and medium-term prognosis in patients with heart failure and preserved systolic ventricular function compared to those with systolic dysfunction. 153 patients were included, 62 with preserved systolic ventricular function (left ventricular ejection fraction > or = 45%) and 91 with impaired systolic ventricular function (left ventricular ejection fraction < 45%). The mean follow-up period was 25 10 months. Mean age was similar (66 10 vs. 65 10; p = 0.54). There was a higher proportion of women among patients with preserved systolic function (53% vs. 28%; p < 0.01). Ischemic and idiopathic cardiomyopathy were the most common causes of heart failure in patients with systolic dysfunction, whereas valvular disease and hypertensive cardiopathy were the most common in patients with preserved systolic function. Angiotensin-converting enzyme inhibitors and beta-blockers were more often prescribed in patients with impaired systolic ventricular function (86% vs. 52%; p < 0.01 and 33% vs. 11%; p < 0.01, respectively). There were no differences between the groups in terms of mortality rate (37% vs. 29%), readmission rate for other causes (29% vs. 23%), readmission rate for heart failure (45% vs. 45%), cumulative survival (51% vs. 62%) and the likelihood of not being readmitted for heart failure (50% vs. 52%). In the multivariate analysis, left ventricular ejection fraction was not a predictor of death or readmission because of heart failure. In a large proportion of patients with heart failure, systolic ventricular function is preserved. Despite the clinical differences between patients with preserved and impaired systolic ventricular function, the medium-term prognosis was similar in both groups.

Numerical model of total artificial heart hemodynamics and the effect of its size on stress accumulation.

PubMed

Marom, Gil; Chiu, Wei-Che; Slepian, Marvin J; Bluestein, Danny

2014-01-01

The total artificial heart (TAH) is a bi-ventricular mechanical circulatory support device that replaces the heart in patients with end-stage congestive heart failure. The device acts as blood pump via pneumatic activation of diaphragms altering the volume of the ventricular chambers. Flow in and out of the ventricles is controlled by mechanical heart valves. The aim of this study is to evaluate the flow regime in the TAH and to estimate the thrombogenic potential during systole. Toward that goal, three numerical models of TAHs of differing sizes, that include the deforming diaphragm and the blood flow from the left chamber to the aorta, are introduced. A multiphase model with injection of platelet particles is employed to calculate their trajectories. The shear stress accumulation in the three models are calculated along the platelets trajectories and their probability density functions, which represent the `thrombogenic footprint' of the device are compared. The calculated flow regime successfully captures the mitral regurgitation and the flows that open and close the aortic valve during systole. Physiological velocity magnitudes are found in all three models, with higher velocities and increased stress accumulation predicted for smaller devices.

From Shuttle Main Engine to the Human Heart: A Presentation to the Federal Lab Consortium for Technology Transfer

NASA Technical Reports Server (NTRS)

Fogarty, Jennifer A.

2010-01-01

A NASA engineer received a heart transplant performed by Drs. DeBakey and Noon after suffering a serious heart attack. 6 months later that engineer returned to work at NASA determined to use space technology to help people with heart disease. A relationship between NASA and Drs. DeBakey and Noon was formed and the group worked to develop a low cost, low power implantable ventricular assist device (VAD). NASA patented the method to reduce pumping damage to red blood cells and the design of a continuous flow heart pump (#5,678,306 and #5,947,892). The technology and methodology were licensed exclusively to MicroMed Technology, Inc.. In late 1998 MicroMed received international quality and electronic certifications and began clinical trials in Europe. Ventricular assist devices were developed to bridge the gap between heart failure and transplant. Early devices were cumbersome, damaged red blood cells, and increased the risk of developing dangerous blood clots. Application emerged from NASA turbopump technology and computational fluid dynamics analysis capabilities. To develop the high performance required of the Space Shuttle main engines, NASA pushed the state of the art in the technology of turbopump design. NASA supercomputers and computational fluid dynamics software developed for use in the modeling analysis of fuel and oxidizer flow through rocket engines was used in the miniaturization and optimization of a very small heart pump. Approximately 5 million people worldwide suffer from chronic heart failure at a cost of 40 billion dollars In the US, more than 5000 people are on the transplant list and less than 3000 transplants are performed each year due to the lack of donors. The success of ventricular assist devices has led to an application as a therapeutic destination as well as a bridge to transplant. This success has been attributed to smaller size, improved efficiency, and reduced complications such as the formation of blood clots and infection.

Preoperative levosimendan decreases mortality and the development of low cardiac output in high-risk patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting with cardiopulmonary bypass

PubMed Central

Levin, Ricardo; Degrange, Marcela; Del Mazo, Carlos; Tanus, Eduardo; Porcile, Rafael

2012-01-01

BACKGROUND: The calcium sensitizer levosimendan has been used in cardiac surgery for the treatment of postoperative low cardiac output syndrome (LCOS) and difficult weaning from cardiopulmonary bypass (CPB). OBJECTIVES: To evaluate the effects of preoperative treatment with levosimendan on 30-day mortality, the risk of developing LCOS and the requirement for inotropes, vasopressors and intra-aortic balloon pumps in patients with severe left ventricular dysfunction. METHODS: Patient with severe left ventricular dysfunction and an ejection fraction <25% undergoing coronary artery bypass grafting with CPB were admitted 24 h before surgery and were randomly assigned to receive levosimendan (loading dose 10 μg/kg followed by a 23 h continuous infusion of 0.1μg/kg/min) or a placebo. RESULTS: From December 1, 2002 to June 1, 2008, a total of 252 patients were enrolled (127 in the levosimendan group and 125 in the control group). Individuals treated with levosimendan exhibited a lower incidence of complicated weaning from CPB (2.4% versus 9.6%; P<0.05), decreased mortality (3.9% versus 12.8%; P<0.05) and a lower incidence of LCOS (7.1% versus 20.8%; P<0.05) compared with the control group. The levosimendan group also had a lower requirement for inotropes (7.9% versus 58.4%; P<0.05), vasopressors (14.2% versus 45.6%; P<0.05) and intra-aortic balloon pumps (6.3% versus 30.4%; P<0.05). CONCLUSION: Patients with severe left ventricle dysfunction (ejection fraction <25%) undergoing coronary artery bypass grafting with CPB who were pretreated with levosimendan exhibited lower mortality, a decreased risk for developing LCOS and a reduced requirement for inotropes, vasopressors and intra-aortic balloon pumps. Studies with a larger number of patients are required to confirm whether these findings represent a new strategy to reduce the operative risk in this high-risk patient population. PMID:23620700

Predictors of new malignant ventricular arrhythmias after coronary surgery: a case-control study.

PubMed

Ascione, Raimondo; Reeves, Barnaby C; Santo, Kirkpatrick; Khan, Nouman; Angelini, Gianni D

2004-05-05

We sought to investigate the relationship between perioperative factors and the occurrence of ventricular tachycardia (VT) and ventricular fibrillation (VF), as well as the impact of VT/VF on early and late mortality. Both VT and VF are rare but serious complications after coronary artery bypass graft surgery (CABG), and their etiology and implications remain uncertain. Data on 4,411 consecutive patients undergoing CABG (1,154 [25.8%] had off-pump surgery) between April 1996 and September 2001 were extracted from a prospective database and analyzed. Odds ratios (ORs) describing associations between possible risk factors and VT/VF were estimated separately. Factors observed to be significantly associated with VT/VF were further investigated using multivariate logistic regression. Sixty-nine patients suffered VT/VF (1.6%). There were 61 (1.4%) in-hospital/30-day deaths, 15 among patients who had postoperative VT/VF (21.7%). Patient factors independently associated with an increase in the odds of VT/VF included age <65 years, female gender, body mass index <25 kg/m(2), unstable angina, moderate or poor ejection fraction, and the need for inotropes and an intra-aortic balloon pump (OR 1.72 to 4.47, p < 0.05). After adjustment, off-pump surgery was associated with a substantial but nonsignificant protective effect against VT/VF (OR 0.53, 95% confidence interval [CI] 0.25 to 1.13; p = 0.10). Actuarial survival at two years was 98.2% among patients who had VT/VF and who survived to discharge/30 days, compared with 97.0% for the control group (adjusted hazard ratio 0.96 (95% CI 0.40 to 2.31, p = 0.92). The incidence of VT/VF is low in patients undergoing coronary surgery but is associated with high in-hospital mortality. The late survival of the discharged VT/VF patients compares favorably with that of controls.

Combined short-arm centrifuge and aerobic exercise training improves cardiovascular function and physical working capacity in humans.

PubMed

Yang, Chang-Bin; Zhang, Shu; Zhang, Yu; Wang, Bing; Yao, Yong-Jie; Wang, Yong-Chun; Wu, Yan-Hong; Liang, Wen-Bin; Sun, Xi-Qing

2010-12-01

Musculoskeletal and cardiovascular deconditioning occurring in long-term spaceflight gives rise to the needs to develop new strategies to counteract these adverse effects. Short-arm centrifuge combined with ergometer has been proposed as a strategy to counteract adverse effects of microgravity. This study sought to investigate whether the combination of short-arm centrifuge and aerobic exercise training have advantages over short-arm centrifuge or aerobic exercise training alone. One week training was conducted by 24 healthy men. They were randomly divided into 3 groups: (1) short-arm centrifuge training, (2) aerobic exercise training, 40 W, and (3) combined short-arm centrifuge and aerobic exercise training. Before and after training, the cardiac pump function represented by stroke volume, cardiac output, left ventricular ejection time, and total peripheral resistance was evaluated. Variability of heart rate and systolic blood pressure were determined by spectral analysis. Physical working capacity was surveyed by near maximal physical working capacity test. The 1-week combined short-arm centrifuge and aerobic exercise training remarkably ameliorated the cardiac pump function and enhanced vasomotor sympathetic nerve modulation and improved physical working capacity by 10.9% (P<.05, n=8). In contrast, neither the short-arm centrifuge nor the aerobic exercise group showed improvements in these functions. These results demonstrate that combined short-arm centrifuge and aerobic exercise training has advantages over short-arm centrifuge or aerobic exercise training alone in influencing several physiologically important cardiovascular functions in humans. The combination of short-arm centrifuge and aerobic exercise offers a promising countermeasure to microgravity.

Modeling our understanding of the His-Purkinje system.

PubMed

Vigmond, Edward J; Stuyvers, Bruno D

2016-01-01

The His-Purkinje System (HPS) is responsible for the rapid electric conduction in the ventricles. It relays electrical impulses from the atrioventricular node to the muscle cells and, thus, coordinates the contraction of ventricles in order to ensure proper cardiac pump function. The HPS has been implicated in the genesis of ventricular tachycardia and fibrillation as a source of ectopic beats, as well as forming distinct portions of reentry circuitry. Despite its importance, it remains much less well characterized, structurally and functionally, than the myocardium. Notably, important differences exist with regard to cell structure and electrophysiology, including ion channels, intracellular calcium handling, and gap junctions. Very few computational models address the HPS, and the majority of organ level modeling studies omit it. This review will provide an overview of our current knowledge of structure and function (including electrophysiology) of the HPS. We will review the most recent advances in modeling of the system from the single cell to the organ level, with considerations for relevant interspecies distinctions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a hybrid (numerical-hydraulic) circulatory model: prototype testing and its response to IABP assistance.

PubMed

Ferrari, G; Kozarski, M; De Lazzari, C; Górczyńska, K; Tosti, G; Darowski, M

2005-07-01

Merging numerical and physical models of the circulation makes it possible to develop a new class of circulatory models defined as hybrid. This solution reduces the costs, enhances the flexibility and opens the way to many applications ranging from research to education and heart assist devices testing. In the prototype described in this paper, a hydraulic model of systemic arterial tree is connected to a lumped parameters numerical model including pulmonary circulation and the remaining parts of systemic circulation. The hydraulic model consists of a characteristic resistance, of a silicon rubber tube to allow the insertion of an Intra-Aortic Balloon Pump (IABP) and of a lumped parameters compliance. Two electro-hydraulic interfaces, realized by means of gear pumps driven by DC motors, connect the numerical section with both terminals of the hydraulic section. The lumped parameters numerical model and the control system (including analog to digital and digital to analog converters)are developed in LabVIEW environment. The behavior of the model is analyzed by means of the ventricular pressure-volume loops and the time courses of arterial and ventricular pressures and flows in different circulatory conditions. A simulated pathological condition was set to test the IABP and verify the response of the system to this type of mechanical circulatory assistance. The results show that the model can represent hemodynamic relationships in different ventricular and circulatory conditions and is able to react to the IABP assistance.

Remote monitoring of left ventricular assist device parameters after HeartAssist-5 implantation.

PubMed

Pektok, Erman; Demirozu, Zumrut Tuba; Arat, Nurcan; Yildiz, Omer; Oklu, Emine; Eker, Deniz; Ece, Ferah; Ciftci, Cavlan; Yazicioglu, Nuran; Bayindir, Osman; Kucukaksu, Deniz Suha

2013-09-01

Although several left ventricular assist devices (LVADs) have been used widely, remote monitoring of LVAD parameters has been available only recently. We present our remote monitoring experience with an axial-flow LVAD (HeartAssist-5, MicroMed Cardiovascular, Inc., Houston, TX, USA). Five consecutive patients who were implanted a HeartAssist-5 LVAD because of end-stage heart failure due to ischemic (n=4) or idiopathic (n=1) cardiomyopathy, and discharged from hospital between December 2011 and January 2013 were analyzed. The data (pump speed, pump flow, power consumption) obtained from clinical visits and remote monitoring were studied. During a median follow-up of 253 (range: 80-394) days, fine tuning of LVADs was performed at clinical visits. All patients are doing well and are in New York Heart Association Class-I/II. A total of 39 alarms were received from three patients. One patient was hospitalized for suspected thrombosis and was subjected to physical examinations as well as laboratory and echocardiographic evaluations; however, no evidence of thrombus washout or pump thrombus was found. The patient was treated conservatively. Remaining alarms were due to insufficient water intake and were resolved by increased water consumption at night and summer times, and fine tuning of pump speed. No alarms were received from the remaining two patients. We believe that remote monitoring is a useful technology for early detection and treatment of serious problems occurring out of hospital thereby improving patient care. Future developments may ease troubleshooting, provide more data from the patient and the pump, and eventually increase physician and patient satisfaction. Despite all potential clinical benefits, remote monitoring should be taken as a supplement to rather than a substitute for routine clinical visits for patient follow-up. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

The logistics and cost-effectiveness of circulatory support: advantages of the ABIOMED BVS 5000.

PubMed

Couper, G S; Dekkers, R J; Adams, D H

1999-08-01

In 1994, the ABIOMED BVS 5000 was incorporated into our acute cardiac assist armamentarium. This report is a general overview of our experience. A hypothetical cost analysis focusing on specific devices and device-related personnel contrasted the BVS 5000 with our prior model of centrifugal pump use. In 3 years, 22 patients were supported with the BVS 5000, as a biventricular assist device in 40%, right ventricular assist device in 27%, and left ventricular assist device in 32%. Indications were postcardiotomy support in 12, acute myocarditis in 2, bridge to transplant in 4, and failed heart transplant in 4. The cost analysis was performed retrospectively. The actual cost of disposable blood pumps, including replacement pumps, and cannulae constituted the BVS cost. The hypothetical centrifugal costs included the disposables, replacement cones, as well as the labor costs of the continuous perfusionist coverage. Of the 22 patients, 10 (45%) were weaned and 13 (59%) were successfully discharged. Five patients were transplanted while on BVS 5000 support, accounting for a higher rate of discharge. Comparison of "actual" BVS costs with "projected" centrifugal costs revealed differences based upon the intended application of the BVS. In bridge-to-transplant patients with long duration of support, the daily cost of support was dramatically lower with the BVS 5000. For short-term postcardiotomy support, acute myocarditis, or failed transplant, the differences were small. Because the BVS 5000 was readily managed by the intensive care unit nursing staff, this system displaced centrifugal systems in our program. Outcome measures of weaning and successful discharge were improved relative to our prior experience with centrifugal pumps. Even without taking indirect costs into account, the hypothetical cost analysis supported continued use of the BVS system for acute cardiac assistance.

Catheter ablation for premature ventricular contractions and ventricular tachycardia in patients with heart failure.

PubMed

Kumar, Saurabh; Stevenson, William G; John, Roy M

2014-09-01

Ventricular arrhythmias (VA) are a significant contributor to morbidity and mortality in patients with heart failure (HF). Implantable cardioverter defibrillators are effective in reducing mortality, but do not prevent arrhythmia recurrence. There is increasing recognition that frequent premature ventricular contractions or repetitive ventricular tachycardia may also lead to new onset ventricular dysfunction or deterioration of ventricular function in patients with pre-existing HF. Suppression of the arrhythmia may lead to recovery of ventricular function. Catheter ablation has emerged as a safe and effective treatment option for reducing arrhythmia recurrence and for suppression of PVCs but its efficacy is governed by the nature of the arrhythmias, the underlying HF substrate and the accessibility of the arrhythmia substrates to ablation.

Is right ventricular mid-septal pacing superior to apical pacing in patients with high degree atrio-ventricular block and moderately depressed left ventricular function?

PubMed

Chen, Kang; Mao, Ye; Liu, Shao-hua; Wu, Qiong; Luo, Qing-zhi; Pan, Wen-qi; Jin, Qi; Zhang, Ning; Ling, Tian-you; Chen, Ying; Gu, Gang; Shen, Wei-feng; Wu, Li-qun

2014-06-01

We are aimed to investigate whether right ventricular mid-septal pacing (RVMSP) is superior to conventional right ventricular apical pacing (RVAP) in improving clinical functional capacity and left ventricular ejection fraction (LVEF) for patients with high-degree atrio-ventricular block and moderately depressed left ventricle (LV) function. Ninety-two patients with high-degree atrio-ventricular block and moderately reduced LVEF (ranging from 35% to 50%) were randomly allocated to RVMSP (n=45) and RVAP (n=47). New York Heart Association (NYHA) functional class, echocardiographic LVEF, and distance during a 6-min walk test (6MWT) were determined at 18 months after pacemaker implantation. Serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Compared with baseline, NYHA functional class remained unchanged at 18 months, distance during 6MWT (485 m vs. 517 m) and LVEF (36.7% vs. 41.8%) were increased, but BNP levels were reduced (2352 pg/ml vs. 710 pg/ml) in the RVMSP group compared with those in the RVAP group, especially in patients with LVEF 35%-40% (for all comparisons, P<0.05). However, clinical function capacity and LV function measurements were not significantly changed in patients with RVAP, despite the pacing measurements being similar in both groups, such as R-wave amplitude and capture threshold. RVMSP provides a better clinical utility, compared with RVAP, in patients with high-degree atrioventricular block and moderately depressed LV function whose LVEF levels ranged from 35% to 40%.

Genetic algorithm optimization of transcutaneous energy transmission systems for implantable ventricular assist devices.

PubMed

Byron, Kelly; Bluvshtein, Vlad; Lucke, Lori

2013-01-01

Transcutaneous energy transmission systems (TETS) wirelessly transmit power through the skin. TETS is particularly desirable for ventricular assist devices (VAD), which currently require cables through the skin to power the implanted pump. Optimizing the inductive link of the TET system is a multi-parameter problem. Most current techniques to optimize the design simplify the problem by combining parameters leading to sub-optimal solutions. In this paper we present an optimization method using a genetic algorithm to handle a larger set of parameters, which leads to a more optimal design. Using this approach, we were able to increase efficiency while also reducing power variability in a prototype, compared to a traditional manual design method.

[A Comparison Study on Early Damage Detection of Left Ventricular Function Based on Doppler Imaging Method for Children with Tumor].

PubMed

Liu, Ying; Zhang, Haowei; Zhang, Hang

2015-12-01

The early damage detection and evaluation are of great significance in treatment and prognosis to the left ventricular function for children with tumor. In this paper, it is reported that the early damage of the left ventricular function was observed by pulsed wave Doppler (PWD) and tissue Doppler imaging (TDI) in our laboratory. Eighty children half a year to fourteen years old were included in this study. The cardiac function indices in chemotherapy group and control group were measured and compared. The results showed that there was significant difference in mitral and tricuspid annulus flow spectrum between the two groups. Compared with PWD,TDI is more prompt, objective and accurate in detecting early damage of left ventricular function in children with tumor. And TDI is a good method for early identification of ventricular function damage in children with tumor.

Left atrial function in heart failure with impaired and preserved ejection fraction.

PubMed

Fang, Fang; Lee, Alex Pui-Wai; Yu, Cheuk-Man

2014-09-01

Left atrial structural and functional changes in heart failure are relatively ignored parts of cardiac assessment. This review illustrates the pathophysiological and functional changes in left atrium in heart failure as well as their prognostic value. Heart failure can be divided into those with systolic dysfunction and heart failure with preserved ejection fraction (HFPEF). Left atrial enlargement and dysfunction commonly occur in systolic heart failure, in particular, in idiopathic dilated cardiomyopathy. Atrial enlargement and dysfunction also carry important prognostic value in systolic heart failure, independently of known parameters such as left ventricular ejection fraction. In HFPEF, there is evidence of left atrial enlargement, impaired atrial compliance, and reduction of atrial pump function. This occurs not only at rest but also during exercise, indicating significant impairment of atrial contractile reserve. Furthermore, atrial dyssynchrony is common in HFPEF. These factors further contribute to the development of new onset or progression of atrial arrhythmias, in particular, atrial fibrillation. Left atrial function is an integral part of cardiac function and its structural and functional changes in heart failure are common. As changes of left atrial structure and function have different clinical implications in systolic heart failure and HFPEF, routine assessment is warranted.

Effects of increasing left ventricular filling pressure in patients with acute myocardial infarction

PubMed Central

Russell, Richard O.; Rackley, Charles E.; Pombo, Jaoquin; Hunt, David; Potanin, Constantine; Dodge, Harold T.

1970-01-01

Left ventricular performance in 19 patients with acute myocardial infarction has been evaluated by measuring left ventricular response in terms of cardiac output, stroke volume, work, and power to progressive elevation of filling pressure accomplished by progressive expansion of blood volume with rapid infusion of low molecular weight dextran. Such infusion can elevate the cardiac output, stroke volume, work, and power and thus delineate the function of the left ventricle by Frank-Starling function curves. Left ventricular filling pressure in the range of 20-24 mm Hg was associated with the peak of the curves and when the filling pressure exceeded this range, the curves became flattened or decreased. An increase in cardiac output could be maintained for 4 or more hr. Patients with a flattened function curve had a high mortality in the ensuing 8 wk. The function curve showed improvement in myocardial function during the early convalescence. When left ventricular filling pressure is monitored directly or as pulmonary artery end-diastolic pressure, low molecular weight dextran provides a method for assessment of left ventricular function. Images PMID:5431663

Epinephrine and left atrial and left ventricular diastolic function decrease in normal subjects.

PubMed

Fuenmayor, Abdel J; Solórzano, Moisés I; Gómez, Luisangelly

2016-10-01

We assessed the effect of epinephrine over left atrial and left ventricular diastolic function in subjects without structural heart disease. Twenty-seven, 34.6±17.2year-old patients without structural heart disease were included. Intravenous epinephrine (50 to 100ng/kg/min) was infused. Left atrial and ventricular functions were evaluated by means of echocardiography before and during the epinephrine infusion. No complications were observed. Significant increases in heart rate and systolic blood pressure were recorded. Both left atrial (minimal and maximal) volumes increased but increase in the minimal volume was more pronounced, and the ejection fraction diminished. Left atrial expansion index decreased and the fraction of left ventricular inflow volume resulting from atrial contraction increased. Two patients displayed abnormal left ventricular diastolic function. During epinephrine infusion, E/A and e' decreased, and isovolumetric relaxation time increased. In this group of young adults without structural heart disease, epinephrine infusion was safe, did not produce any complications, and induced a small but significant decrease in left atrial function and left ventricular diastolic function. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The value of right ventricular longitudinal strain in the evaluation of adult patients with repaired tetralogy of Fallot: a new tool for a contemporary challenge.

PubMed

Almeida-Morais, Luís; Pereira-da-Silva, Tiago; Branco, Luísa; Timóteo, Ana T; Agapito, Ana; de Sousa, Lídia; Oliveira, José A; Thomas, Boban; Jalles-Tavares, Nuno; Soares, Rui; Galrinho, Ana; Cruz-Ferreira, Rui

2017-04-01

The role of right ventricular longitudinal strain for assessing patients with repaired tetralogy of Fallot is not fully understood. In this study, we aimed to evaluate its relation with other structural and functional parameters in these patients. Patients followed-up in a grown-up CHD unit, assessed by transthoracic echocardiography, cardiac MRI, and treadmill exercise testing, were retrospectively evaluated. Right ventricular size and function and pulmonary regurgitation severity were assessed by echocardiography and MRI. Right ventricular longitudinal strain was evaluated in the four-chamber view using the standard semiautomatic method. In total, 42 patients were included (61% male, 32±8 years). The mean right ventricular longitudinal strain was -16.2±3.7%, and the right ventricular ejection fraction, measured by MRI, was 42.9±7.2%. Longitudinal strain showed linear correlation with tricuspid annular systolic excursion (r=-0.40) and right ventricular ejection fraction (r=-0.45) (all p<0.05), which in turn showed linear correlation with right ventricular fractional area change (r=0.50), pulmonary regurgitation colour length (r=0.35), right ventricular end-systolic volume (r=-0.60), and left ventricular ejection fraction (r=0.36) (all p<0.05). Longitudinal strain (β=-0.72, 95% confidence interval -1.41, -0.15) and left ventricular ejection fraction (β=0.39, 95% confidence interval 0.11, 0.67) were independently associated with right ventricular ejection fraction. The best threshold of longitudinal strain for predicting a right ventricular ejection fraction of <40% was -17.0%. Right ventricular longitudinal strain is a powerful method for evaluating patients with tetralogy of Fallot. It correlated with echocardiographic right ventricular function parameters and was independently associated with right ventricular ejection fraction derived by MRI.

The helical ventricular myocardial band of Torrent-Guasp.

PubMed

Kocica, Mladen J; Corno, Antonio F; Lackovic, Vesna; Kanjuh, Vladimir I

2007-01-01

We live in an era of substantial progress in understanding myocardial structure and function at genetic, molecular, and microscopic levels. Yet, ventricular myocardium has proven remarkably resistant to macroscopic analyses of functional anatomy. Pronounced and practically indefinite global and local structural anisotropy of its fibers and other ventricular wall constituents produces electrical and mechanical properties that are nonlinear, anisotropic, time varying, and spatially inhomogeneous. The helical ventricular myocardial band of Torrent-Guasp is a revolutionary new concept in understanding global, 3-dimensional, functional architecture of the ventricular myocardium. This concept defines the principal, cumulative vectors, integrating the tissue architecture (ie, form) and net forces developed (ie, function) within the ventricular mass. The primary purpose of this review is to emphasize the importance of this concept, in the light of collaborative efforts to establish an integrative approach, defining ventricular form and function by linking across multiple scales of biological organization, as explained in the ongoing Physiome project. Because one of the most important scientific missions in this century is integration of basic research with clinical medicine, we believe that this knowledge is not of merely academic importance, but is also the essential prerequisite in clinical evaluation and treatment of different heart diseases.

Prototype continuous flow ventricular assist device supported on magnetic bearings.

PubMed

Allaire, P E; Kim, H C; Maslen, E H; Olsen, D B; Bearnson, G B

1996-06-01

This article describes a prototype continuous flow pump (CFVAD2) fully supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. The pump delivered 6 L/min of flow at 100 mm Hg of differential pressure head operating at 2,400 rpm in water. The pump is totally supported in 4 magnetic bearings: 2 radial and 2 thrust. Magnetic bearings offer the advantages of no required lubrication and large operating clearances. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity and current gains are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water. Much lower levels of force were found than were expected, allowing for a very significant reduction in the size of the next prototype. Hemolysis levels were measured in the prototype pump and found not to indicate damage to the blood cells.

THE EFFECT OF RIGHT VENTRICULAR PACEMAKER LEAD POSITION ON FUNCTIONAL STATUS IN PATIENTS WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTION.

PubMed

Mitov, Vladimir M; Perisic, Zoran; Jolic, Aleksandar; Kostic, Tomislav; Aleksic, Aleksandar; Aleksic, Zeljka

2016-07-01

The study was aimed at assessing the difference between the right ventricle apex versus the right ventricular outflow tract lead position in functional capacity in the patients with the preserved left ventricular ejection fraction after 12 months of pacemaker stimulation. This was a prospective, randomized, follow-up study, which lasted for 12 months. The study sample included 132 consecutive patients who were implanted with permanent anti-bradicardiac pacemaker. Regarding the right ventricular lead position the patients were divided into two groups: the right ventricle apex group consisting of 61 patients with right ventricular apex lead position. The right ventricular outflow tract group included 71 patients with right ventricular outflow tract lead position. Functional capacity was assessed by Minnesota Living With Heart Failure score, New York Heart Association class and Six Minute Walk Test. Left ventricular ejection fraction was assessed by echocardiography. Minnesota Living With Heart Failure score and New York Heart Association class had a statistically significant improvement in both study groups. The patients from right ventricle apex group walked 20.95% (p=O.03) more in comparison to starting values. The patients from right ventricular outflow tract group walked only 13.63% (p=0.09) longer distance than the startingoneConclusion. Analysis of tests of functional status New York Heart Association class and Minnesota Living With Heart Failure questionnaire showed an even improvement in the right ventricle apex and right ventricular outflow tract groups. Analysis of 6 minute walk test showed that only the patients with the preserved left ventricular ejection fraction from the right ventricle apex group had a significant improvement after 12 months of pacemaker stimulation..

Right ventricular dysfunction affects survival after surgical left ventricular restoration.

PubMed

Couperus, Lotte E; Delgado, Victoria; Palmen, Meindert; van Vessem, Marieke E; Braun, Jerry; Fiocco, Marta; Tops, Laurens F; Verwey, Harriëtte F; Klautz, Robert J M; Schalij, Martin J; Beeres, Saskia L M A

2017-04-01

Several clinical and left ventricular parameters have been associated with prognosis after surgical left ventricular restoration in patients with ischemic heart failure. The aim of this study was to determine the prognostic value of right ventricular function. A total of 139 patients with ischemic heart failure (62 ± 10 years; 79% were male; left ventricular ejection fraction 27% ± 7%) underwent surgical left ventricular restoration. Biventricular function was assessed with echocardiography before surgery. The independent association between all-cause mortality and right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain was assessed. The additive effect of multiple impaired right ventricular parameters on mortality also was assessed. Baseline right ventricular fractional area change was 42% ± 9%, tricuspid annular plane systolic excursion was 18 ± 3 mm, and right ventricular longitudinal peak systolic strain was -24% ± 7%. Within 30 days after surgery, 15 patients died. Right ventricular fractional area change (hazard ratio, 0.93; 95% confidence interval, 0.88-0.98; P < .01), tricuspid annular plane systolic excursion (hazard ratio, 0.80; 95% confidence interval, 0.66-0.96; P = .02), and right ventricular longitudinal peak systolic strain (hazard ratio, 1.15; 95% confidence interval, 1.05-1.26; P < .01) were independently associated with 30-day mortality, after adjusting for left ventricular ejection fraction and aortic crossclamping time. Right ventricular function was impaired in 21%, 20%, and 27% of patients on the basis of right ventricular fractional area change, tricuspid annular plane systolic excursion, and right ventricular longitudinal peak systolic strain, respectively. Any echocardiographic parameter of right ventricular dysfunction was present in 39% of patients. The coexistence of several impaired right ventricular parameters per patient was independently associated with increased 30-day mortality (hazard ratio, 2.83; 95% confidence interval, 1.64-4.87, P < .01 per additional impaired parameter). Baseline right ventricular systolic dysfunction is independently associated with increased mortality in patients with ischemic heart failure undergoing surgical left ventricular restoration. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Gender differences in left ventricular function in patients with isolated aortic stenosis.

PubMed

Favero, Luca; Giordan, Massimo; Tarantini, Giuseppe; Ramondo, Angelo Bruno; Cardaioli, Paolo; Isabella, Giambattista; Chioin, Raffaello; Lupia, Mario; Razzolini, Renato

2003-05-01

Hypertrophic response of the left ventricle to systolic overload in aortic stenosis appears to be gender-dependent. To examine gender-related differences in left ventricular (LV) function in patients with isolated severe aortic stenosis, 145 patients (65 women, 80 men; mean age 66 +/- 8 years; range: 50 to 89 years) with aortic valve area <0.8 cm2 who underwent cardiac catheterization were studied. No patient had associated myocardial, coronary or other valve disease; patients with diabetes mellitus and systemic hypertension were excluded. No significant differences were seen in aortic valve area between men and women. Neither were there any significant gender-related differences in LV end-systolic and end-diastolic volumes, LV end-diastolic pressure, LV mass indexed by body surface area, LV mass:volume ratio, LV mass:height ratio, elastic stiffness constant, ejection fraction, pulmonary wedge pressure, pulmonary arteriolar resistance and preload. Women showed significantly higher mean transaortic gradient, LV peak systolic pressure and peak systolic stress, end-systolic stress:end-systolic volume ratio, heart rate and cardiac index. In the subgroup of patients with LV pressure >199 mmHg, the mass:volume ratio was increased in men compared with women; of note, the mass:volume ratio in women was not increased in this subgroup compared with the general population. LV pump function in this subgroup was normal and did not differ between men and women. Although no clear-cut difference in hemodynamic parameters was seen, there was a trend towards a less compensatory increase in LV mass in females.

Heat Generation in Axial and Centrifugal Flow Left Ventricular Assist Devices.

PubMed

Yost, Gardner; Joseph, Christine Rachel; Royston, Thomas; Tatooles, Antone; Bhat, Geetha

Despite increasing use of left ventricular assist devices (LVADs) as a surgical treatment for advanced heart failure in an era of improved outcomes with LVAD support, the mechanical interactions between these pumps and the cardiovascular system are not completely understood. We utilized an in vitro mock circulatory loop to analyze the heat production incurred by operation of an axial flow and centrifugal flow LVAD. A HeartMate II and a HeartWare HVAD were connected to an abbreviated flow loop and were implanted in a viscoelastic gel. Temperature was measured at the surface of each LVAD. Device speed and fluid viscosity were altered and, in the HeartMate II, as artificial thrombi were attached to the inflow stator, impeller, and outflow stator. The surface temperatures of both LVADs increased in all trials and reached a plateau within 80 minutes of flow initiation. Rate of heat generation and maximum system temperature were greater when speed was increased, when viscosity was increased, and when artificial thrombi were attached to the HeartMate II impeller. Normal operation of these two widely utilized LVADs results in appreciable heat generation in vitro. Increased pump loading resulted in more rapid heat generation, which was particularly severe when a large thrombus was attached to the impeller of the HeartMate II. While heat accumulation in vivo is likely minimized by greater dissipation in the blood and soft tissues, focal temperature gains with the pump housing of these two devices during long-term operation may have negative hematological consequences.

Detection of ventricular fibrillation with a ventricular monopolar catheter electrode.

PubMed

Voelz, M B; Wessale, J L; Geddes, L A; Patel, U H

1991-01-01

This report describes the use of right ventricular impedance (RVZ) sensing with a monopolar electrode to identify the cessation of pumping with the onset of ventricular fibrillation. RVZ, ECG (lead II), and femoral artery pressure were monitored in seven anesthetized dogs. An impedance recorder (10-kHz, 100-microA peak-to-peak current) was used to measure RVZ between a monopolar, catheter-mounted electrode placed in the right ventricle and an indifferent electrode (8.5-cm diameter plate) sutured to the right chest wall. The catheter electrode was either 0.4 cm or 1.2 cm long and had a surface area of 0.50 cm2 or 1.50 cm2, respectively. A monopolar electrode was positioned at the apex of the right ventricle or midway between the apex and the tricuspid valve. The peak-to-peak amplitude of the pulsatile cardiac-induced impedance change was measured prior to and throughout an episode of ventricular fibrillation lasting up to 1 minute. On the average, the amplitude of the pulsatile RVZ signal after 10 seconds of fibrillation decreased by 79% of the prefibrillation amplitude. The 1.2-cm electrode located at the middle of the ventricle showed the largest reduction in pulsatile impedance, the amplitude being very small at 10 seconds. It is concluded that sensing RVZ by a monopolar electrode located on a catheter in the mid-ventricle can provide the mechanical information needed to identify the onset of ventricular fibrillation.

Development of a real-time and quantitative thrombus sensor for an extracorporeal centrifugal blood pump by near-infrared light

PubMed Central

Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Nishida, Masahiro; Mizuno, Tomohiro; Arai, Hirokuni; Maruyama, Osamu

2017-01-01

We developed an optical thrombus sensor for a monopivot extracorporeal centrifugal blood pump. In this study, we investigated its quantitative performance for thrombus detection in acute animal experiments of left ventricular assist using the pump on pathogen-free pigs. Optical fibers were set in the driver unit of the pump. The incident light at the near-infrared wavelength of 810 nm was aimed at the pivot bearing, and the resulting scattered light was guided to the optical fibers. The detected signal was analyzed to obtain the thrombus formation level. As a result, real-time and quantitative monitoring of the thrombus surface area on the pivot bearing was achieved with an accuracy of 3.6 ± 2.3 mm2. In addition, the sensing method using the near-infrared light was not influenced by changes in the oxygen saturation and the hematocrit. It is expected that the developed sensor will be useful for optimal anticoagulation management for long-term extracorporeal circulation therapies. PMID:29359096

Development of a real-time and quantitative thrombus sensor for an extracorporeal centrifugal blood pump by near-infrared light.

PubMed

Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Nishida, Masahiro; Mizuno, Tomohiro; Arai, Hirokuni; Maruyama, Osamu

2018-01-01

We developed an optical thrombus sensor for a monopivot extracorporeal centrifugal blood pump. In this study, we investigated its quantitative performance for thrombus detection in acute animal experiments of left ventricular assist using the pump on pathogen-free pigs. Optical fibers were set in the driver unit of the pump. The incident light at the near-infrared wavelength of 810 nm was aimed at the pivot bearing, and the resulting scattered light was guided to the optical fibers. The detected signal was analyzed to obtain the thrombus formation level. As a result, real-time and quantitative monitoring of the thrombus surface area on the pivot bearing was achieved with an accuracy of 3.6 ± 2.3 mm 2 . In addition, the sensing method using the near-infrared light was not influenced by changes in the oxygen saturation and the hematocrit. It is expected that the developed sensor will be useful for optimal anticoagulation management for long-term extracorporeal circulation therapies.

Left ventricular pressure and volume data acquisition and analysis using LabVIEW.

PubMed

Cassidy, S C; Teitel, D F

1997-03-01

To automate analysis of left ventricular pressure-volume data, we used LabVIEW to create applications that digitize and display data recorded from conductance and manometric catheters. Applications separate data into cardiac cycles, calculate parallel conductance, and calculate indices of left ventricular function, including end-systolic elastance, preload-recruitable stroke work, stroke volume, ejection fraction, stroke work, maximum and minimum derivative of ventricular pressure, heart rate, indices of relaxation, peak filling rate, and ventricular chamber stiffness. Pressure-volume loops can be graphically displayed. These analyses are exported to a text-file. These applications have simplified and automated the process of evaluating ventricular function.

Synergic effects of renin and aldosterone on right ventricular function in hypertension: a tissue Doppler study.

PubMed

Gregori, Mario; Giammarioli, Benedetta; Tocci, Giuliano; Befani, Alberto; Ciavarella, Giuseppino Massimo; Ferrucci, Andrea; Paneni, Francesco

2015-12-01

Right ventricular dysfunction (RVD) is associated with poor cardiovascular outcome. The renin-angiotensin-aldosterone system is involved in alterations of the left ventricular geometry and function. Detrimental effects of the renin-angiotensin-aldosterone system on the right ventricular function are being postulated, but data supporting this assumption are still lacking. The aim of the study was to assess the impact of hyperreninemia, hyperaldosteronism or their combination on right ventricular function in hypertensive individuals. Plasma renin activity (PRA) and plasma aldosterone concentrations (PACs) were measured in 116 hypertensive patients, divided as follows: normal PRA and PAC (n = 38); high PRA and normal PAC (hypereninemia) (n = 26); normal PRA and high PAC (hyperaldosternism) (n = 27); high PRA and PAC (HRA) (n = 25). Echocardiographic evaluation of the left and right ventricles (RV), including tissue Doppler imaging, was performed. RVD was identified by tissue Doppler Imaging-derived Myocardial Performance Index, calculated with a multisegmental approach. Indices of the right ventricular structure and function, as well as the prevalence of RVD, were higher in hyperreninemia and hyperaldosternism groups as compared with the normal group, and a further increase was observed in the HRA patients. Regression models showed a similar risk of RVD in the hyperreninemia and hyperaldosternism patients, regardless of systemic and pulmonary pressure, as well as left ventricular dysfunction. Notably, patients with both hyperreninemia and hyperaldosternism exhibited the strongest association with RVD as compared with patients with only hyperreninemia or hyperaldosternism. Isolated hyperreninemia or hyperaldosternism determines a similar impairment of the right ventricular function, whereas their combination is further detrimental. Renin and aldosterone may represent early biomarkers of right ventricular dysfunction in hypertension.

END-DIASTOLIC FLOW REVERSAL LIMITS THE EFFICACY OF PEDIATRIC INTRAAORTIC BALLOON PUMP COUNTERPULSATION

PubMed Central

Bartoli, Carlo R.; Rogers, Benjamin D.; Ionan, Constantine E.; Koenig, Steven C.; Pantalos, George M.

2013-01-01

OBJECTIVE Counterpulsation with an intraaortic balloon pump (IABP) has not achieved the same successes or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. METHODS In Yorkshire piglets (n=19, 13.0±0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7cc) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. RESULTS Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105±3bmp, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. CONCLUSIONS Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. PMID:24139614

End-diastolic flow reversal limits the efficacy of pediatric intra-aortic balloon pump counterpulsation.

PubMed

Bartoli, Carlo R; Rogers, Benjamin D; Ionan, Constantine E; Pantalos, George M

2014-05-01

Counterpulsation with an intra-aortic balloon pump (IABP) has not achieved the same success or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal. In Yorkshire piglets (n = 19; weight, 13.0 ± 0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7 mL) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres. Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105 ± 3 beats per minute, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship. Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Impact of severe left ventricular dysfunction on in-hospital and mid-term outcomes of Chinese patients undergoing first isolated off-pump coronary artery bypass grafting.

PubMed

Ji, Qiang; Xia, Li Min; Shi, Yun Qing; Ma, Run Hua; Shen, Jin Qiang; Ding, Wen Jun; Wang, Chun Sheng

2017-10-10

Few studies focused on evaluating the impacts of preoperative severe left ventricular dysfunction on clinical outcomes of patients undergoing off-pump coronary artery bypass grafting surgery (OPCAB). This single center retrospective study aimed to evaluate the impacts of severe left ventricular dysfunction on in-hospital and mid-term clinical outcomes of Chinese patients undergoing first, scheduled, and isolated OPCAB surgery. From January 2010 to December 2014, 2032 eligible patients were included in this study and were divided into 3 groups: a severe group (patients with preoperative left ventricular ejection fraction (LVEF) of ≤35%, n = 128), an impaired group (patients with preoperative LVEF of 36-50%, n = 680), and a normal group (patients with preoperative LVEF of >50%, n = 1224). In-hospital and follow-up clinical outcomes were investigated and compared. Patients in the severe group compared to the other 2 groups had higher in-hospital mortality and higher incidences of low cardiac output and prolonged ventilation. Kaplan-Meier curves showed a similar cumulative follow-up survival between the severe group and the impaired group (χ 2  = 1.980, Log-rank p = 0.159) and between the severe group and the normal group (χ 2  = 2.701, Log-rank p = 0.102). Multivariate Cox regression indicated that grouping was not a significant variable related to mid-term all-cause mortality. No significant difference was found in the rate of repeat revascularization between the severe group (2.4%) and the other 2 groups. Patients with preoperative LVEF of ≤35% compared to preoperative LVEF of >35% increased the risk of in-hospital death and incidences of postoperative low cardiac output and prolonged ventilation, but shared similar mid-term all-cause mortality and repeat revascularization after OPCAB surgery.

Left ventricular function before and after kidney transplantation.

PubMed

Omran, Mohammad T; Khakpour, Somayeh; Oliaie, Farshid

2009-06-01

To evaluate left ventricular function by echocardiography before and after kidney transplantation (KT). This analytical study included 50 patients that had successful KT in Shahid Beheshti Hospital, Babol, Iran from October 2005 to December 2007. The echocardiography study was performed by one cardiologist before and at least 3 months after KT. Data were analyzed by SPSS, and a p<0.05 was considered statistically significant. The mean age of patients was 33.94 +/- 11.66 years, 66% were male and 56% less than 45 years old. The ejection fraction and stroke volume after KT increased, however, the left ventricular end diastolic volume, left ventricular end systolic volume, left ventricular end systolic dimension, and left ventricular end diastolic diameter decreased. In patients with end stage renal disease, successful kidney transplantation could improve the function of the left ventricle.

From syncitium to regulated pump: a cardiac muscle cellular update

PubMed Central

2011-01-01

The primary purpose of this article is to present a basic overview of some key teaching concepts that should be considered for inclusion in an six- to eight-lecture introductory block on the regulation of cardiac performance for graduate students. Within the context of cardiac excitation-contraction coupling, this review incorporates information on Ca2+ microdomains and local control theory, with particular emphasis on the role of Ca2+ sparks as a key regulatory component of ventricular myocyte contraction dynamics. Recent information pertaining to local Ca2+ cycling in sinoatrial nodal cells (SANCs) as a mechanism underlying cardiac automaticity is also presented as part of the recently described coupled-clock pacemaker system. The details of this regulation are emerging; however, the notion that the sequestration and release of Ca2+ from internal stores in SANCs (similar to that observed in ventricular myocytes) regulates the rhythmic excitation of the heart (i.e., membrane ion channels) is an important advancement in this area. The regulatory role of cardiac adrenergic receptors on cardiac rate and function is also included, and fundamental concepts related to intracellular signaling are discussed. An important point of emphasis is that whole organ cardiac dynamics can be traced back to cellular events regulating intracellular Ca2+ homeostasis and, as such, provides an important conceptual framework from which students can begin to think about whole organ physiology in health and disease. Greater synchrony of Ca2+-regulatory mechanisms between ventricular and pacemaker cells should enhance student comprehension of complex regulatory phenomenon in cardiac muscle. PMID:21385997

Left heart bypass support with the Rotaflow Centrifugal Pump® as a bridge to decision and recovery in an adult.

PubMed

Kashiwa, Koichi; Nishimura, Takashi; Saito, Aya; Kubo, Hitoshi; Fukaya, Aoi; Tamai, Hisayoshi; Yambe, Tomoyuki; Kyo, Shunei; Ono, Minoru

2012-06-01

Since left heart bypass or biventricular circulatory assist with an extracorporeal centrifugal pump as a bridge to decision or recovery sometimes requires long-time support, the long-term durability of extracorporeal centrifugal pumps is crucial. The Rotaflow Centrifugal Pump(®) (MAQUET Cardiopulmonary AG, Hirrlingen, Germany) is one of the centrifugal pumps available for long-term use in Japan. However, there have been few reports of left heart bypass or biventricular circulatory support over the mid-term. This is a case report of left heart bypass support with the Rotaflow Centrifugal Pump(®) as a bridge to decision and recovery for an adult patient who could not be weaned from cardiopulmonary bypass and percutaneous cardiopulmonary support after cardiac surgery. We could confirm that the patient's consciousness level was normal; however, the patient could not be weaned from the left heart bypass support lasting 1 month. Therefore, the circulatory assist device was switched to the extracorporeal Nipro ventricular assist device (VAD). This time, left heart bypass support could be maintained for 30 days using a single Rotaflow Centrifugal Pump(®). There were no signs of hemolysis during left heart bypass support. The Rotaflow Centrifugal Pump(®) itself may be used as a device for a bridge to decision or recovery before using a VAD in cardiogenic shock patients.

[Long-term effects of hydroxychloroquine on metabolism of serum lipids and left ventricular structure and function in patients of systemic lupus erythematosus].

PubMed

Meng, Juan; Lu, Yuewu; Dong, Xin; Liu, Hongyan

2014-04-08

To observe the long-term effects of hydroxychloroquine treatment on blood lipids and left ventricular function of systemic lupus erythematosus (SLE) patients. A total of 72 SLE patients were randomly divided into 2 groups of hydroxychloroquine treatment (n = 36) and non-hydroxychloroquine (n = 36). The serum level of lipids, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), fractional shortening rate (FS), left ventricular ejection fraction (LVEF) and E/A ratio were measured before, 6 month, 12 month and 2 years after treatment. After long-term use of hydroxychloroquine, there were statistically differences in the levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). And LVEDD, LVWPT and E/A were statistically different (P < 0.05) before and after hydroxychloroquine dosing. The long-term use of hydroxychloroquine may improve lipid metabolism and left ventricular function in SLE patients.

Contemporary trends in cardiogenic shock: Incidence, intra-aortic balloon pump utilisation and outcomes from the London Heart Attack Group.

PubMed

Rathod, Krishnaraj S; Koganti, Sudheer; Iqbal, M Bilal; Jain, Ajay K; Kalra, Sundeep S; Astroulakis, Zoe; Lim, Pitt; Rakhit, Roby; Dalby, Miles C; Lockie, Tim; Malik, Iqbal S; Knight, Charles J; Whitbread, Mark; Mathur, Anthony; Redwood, Simon; MacCarthy, Philip A; Sirker, Alexander; O'Mahony, Constantinos; Wragg, Andrew; Jones, Daniel A

2018-02-01

Cardiogenic shock remains a major cause of morbidity and mortality in patients with ST-segment elevation myocardial infarction. We aimed to assess the current trends in cardiogenic shock management, looking specifically at the incidence, use of intra-aortic balloon pump therapy and outcomes in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention. We undertook an observational cohort study of 21,210 ST-segment elevation myocardial infarction patients treated between 2005-2015 at the eight Heart Attack Centres in London, UK. Patients' details were recorded at the time of the procedure into local databases using the British Cardiac Intervention Society percutaneous coronary intervention dataset. There were 1890 patients who presented with cardiogenic shock. The primary outcome was all-cause mortality at a median follow-up of 4.1 years (interquartile range: 2.2-5.8 years). Increasing rates of cardiogenic shock were seen over the course of the study with consistently high mortality rates of 45-70%. A total of 685 patients underwent intra-aortic balloon pump insertion during primary percutaneous coronary intervention for cardiogenic shock with decreasing rates over time. Those patients undergoing intra-aortic balloon pump therapy were younger, more likely to have poor left ventricular function and less likely to have had previous percutaneous coronary intervention compared to the control group. Procedural success rates were similar (86.0% vs 87.1%, p=0.292) although crude, in-hospital major adverse cardiac event rates were higher (43.8% vs 33.7%, p<0.0001) in patients undergoing intra-aortic balloon pump therapy. Kaplan-Meier analysis demonstrated significantly higher mortality rates in patients receiving intra-aortic balloon pump therapy (50.9% intra-aortic balloon pump vs 39.9% control, p<0.0001) during the follow-up period. After multivariate Cox analysis (hazard ratio 1.04, 95% confidence interval 0.62-1.89) and the use of propensity matching (hazard ratio: 1.29, 95% confidence interval: 0.68-1.45) intra-aortic balloon pump therapy was not associated with mortality. Cardiogenic shock treated by percutaneous coronary intervention is increasing in incidence and remains a condition associated with high mortality and limited treatment options. Intra-aortic balloon pump therapy was not associated with a long-term survival benefit in this cohort and may be associated with increased early morbidity.

Non-functional tricuspid valve disease

PubMed Central

2017-01-01

Only 75% of severe tricuspid regurgitation is classified as functional, or related primarily to pulmonary hypertension, right ventricular dysfunction, or a combination of both. Non-functional tricuspid regurgitation occurs when there is damage to the tricuspid leaflets, chordae, papillary muscles, or annulus, independent of right ventricular dysfunction or pulmonary hypertension. The entities that cause non-functional tricuspid regurgitation include rheumatic and myxomatous disease, acquired and genetic connective tissue disorders, endocarditis, sarcoid, pacing, RV biopsy, blunt trauma, radiation, carcinoid, ergot alkaloids, dopamine agonists, fenfluramine, cardiac tumors, atrial fibrillation, and congenital malformations. Over time, severe tricuspid regurgitation that is initially non-functional, can blend into functional tricuspid regurgitation, related to progressive right ventricular dysfunction. Symptoms and signs, including a falling right ventricular ejection fraction, cardiac cirrhosis, ascites, esophageal varices, and anasarca, may occur insidiously and late, but are associated with substantial morbidity and mortality. Attempted valve repair or replacement at late stages carries a high mortality. Crucial to following patients with severe non-functional tricuspid regurgitation is attention to echo quantification of the tricuspid regurgitation and right ventricular function, patient symptoms, and the physical examination. PMID:28706863

Non-functional tricuspid valve disease.

PubMed

Adler, Dale S

2017-05-01

Only 75% of severe tricuspid regurgitation is classified as functional, or related primarily to pulmonary hypertension, right ventricular dysfunction, or a combination of both. Non-functional tricuspid regurgitation occurs when there is damage to the tricuspid leaflets, chordae, papillary muscles, or annulus, independent of right ventricular dysfunction or pulmonary hypertension. The entities that cause non-functional tricuspid regurgitation include rheumatic and myxomatous disease, acquired and genetic connective tissue disorders, endocarditis, sarcoid, pacing, RV biopsy, blunt trauma, radiation, carcinoid, ergot alkaloids, dopamine agonists, fenfluramine, cardiac tumors, atrial fibrillation, and congenital malformations. Over time, severe tricuspid regurgitation that is initially non-functional, can blend into functional tricuspid regurgitation, related to progressive right ventricular dysfunction. Symptoms and signs, including a falling right ventricular ejection fraction, cardiac cirrhosis, ascites, esophageal varices, and anasarca, may occur insidiously and late, but are associated with substantial morbidity and mortality. Attempted valve repair or replacement at late stages carries a high mortality. Crucial to following patients with severe non-functional tricuspid regurgitation is attention to echo quantification of the tricuspid regurgitation and right ventricular function, patient symptoms, and the physical examination.

In vivo quantification of intraventricular flow during left ventricular assist device support

NASA Astrophysics Data System (ADS)

Vu, Vi; Wong, Kin; Del Alamo, Juan; Aguilo, Pablo M. L.; May-Newman, Karen; Department of Bioengineering, San Diego State University Collaboration; Department of Mechanical; Aerospace Engineering, University of California San Diego Collaboration; Mechanical Assist Device Program, Sharp Memorial Hospital Collaboration

2014-11-01

Left ventricular assist devices (LVADs) are mechanical pumps that are surgically connected to the left ventricle (LV) and aorta to increase aortic flow and end-organ perfusion. Clinical studies have demonstrated that LVADs improve patient health and quality of life and significantly reduce the mortality of cardiac failure. However, In the presence of left ventricular assisted devices (LVAD), abnormal flow patterns and stagnation regions are often linked to thrombosis. The aim of our study is to evaluate the flow patterns in the left ventricle of the LVAD-assisted heart, with a focus on alterations in vortex development and blood stasis. To this aim, we applied color Doppler echocardiography to measure 2D, time resolved velocity fields in patients before and after implantation of LVADs. In agreement with our previous in vitro studies (Wong et al., Journal of Biomechanics 47, 2014), LVAD implantation resulted in decreased flow velocities and increased blood residence time near the outflow tract. The variation of residence time changes with LVAD operational speed was characterized for each patient.

Aortic Wave Dynamics and Its Influence on Left Ventricular Workload

PubMed Central

Pahlevan, Niema M.; Gharib, Morteza

2011-01-01

The pumping mechanism of the heart is pulsatile, so the heart generates pulsatile flow that enters into the compliant aorta in the form of pressure and flow waves. We hypothesized that there exists a specific heart rate at which the external left ventricular (LV) power is minimized. To test this hypothesis, we used a computational model to explore the effects of heart rate (HR) and aortic rigidity on left ventricular (LV) power requirement. While both mean and pulsatile parts of the pressure play an important role in LV power requirement elevation, at higher rigidities the effect of pulsatility becomes more dominant. For any given aortic rigidity, there exists an optimum HR that minimizes the LV power requirement at a given cardiac output. The optimum HR shifts to higher values as the aorta becomes more rigid. To conclude, there is an optimum condition for aortic waves that minimizes the LV pulsatile load and consequently the total LV workload. PMID:21853075

Biomarkers of myocardial stress and fibrosis as predictors of mode of death in patients with chronic heart failure.

PubMed

Ahmad, Tariq; Fiuzat, Mona; Neely, Benjamin; Neely, Megan L; Pencina, Michael J; Kraus, William E; Zannad, Faiez; Whellan, David J; Donahue, Mark P; Piña, Ileana L; Adams, Kirkwood F; Kitzman, Dalane W; O'Connor, Christopher M; Felker, G Michael

2014-06-01

The aim of this study was to determine whether biomarkers of myocardial stress and fibrosis improve prediction of the mode of death in patients with chronic heart failure. The 2 most common modes of death in patients with chronic heart failure are pump failure and sudden cardiac death. Prediction of the mode of death may facilitate treatment decisions. The relationship between amino-terminal pro-brain natriuretic peptide (NT-proBNP), galectin-3, and ST2, biomarkers that reflect different pathogenic pathways in heart failure (myocardial stress and fibrosis), and mode of death is unknown. HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) was a randomized controlled trial of exercise training versus usual care in patients with chronic heart failure due to left ventricular systolic dysfunction (left ventricular ejection fraction ≤35%). An independent clinical events committee prospectively adjudicated mode of death. NT-proBNP, galectin-3, and ST2 levels were assessed at baseline in 813 subjects. Associations between biomarkers and mode of death were assessed using cause-specific Cox proportional hazards modeling, and interaction testing was used to measure differential associations between biomarkers and pump failure versus sudden cardiac death. Discrimination and risk reclassification metrics were used to assess the added value of galectin-3 and ST2 in predicting mode of death risk beyond a clinical model that included NT-proBNP. After a median follow-up period of 2.5 years, there were 155 deaths: 49 from pump failure, 42 from sudden cardiac death, and 64 from other causes. Elevations in all biomarkers were associated with increased risk for both pump failure and sudden cardiac death in both adjusted and unadjusted analyses. In each case, increases in the biomarker had a stronger association with pump failure than sudden cardiac death, but this relationship was attenuated after adjustment for clinical risk factors. Clinical variables along with NT-proBNP levels were stronger predictors of pump failure (C statistic: 0.87) than sudden cardiac death (C statistic: 0.73). Addition of ST2 and galectin-3 led to improved net risk classification of 11% for sudden cardiac death, but not pump failure. Clinical predictors along with NT-proBNP levels were strong predictors of pump failure risk, with insignificant incremental contributions of ST2 and galectin-3. Predictability of sudden cardiac death risk was less robust and enhanced by information provided by novel biomarkers. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

[The effect of atrial pacing on left ventricular diastolic function and BNP levels in patients with DDD pacemaker].

PubMed

Apali, Zeynep; Bayata, Serdar; Yeşil, Murat; Arikan, Erdinç; Postaci, Nursen

2010-08-01

We aimed to investigate the effect of atrial pacing on left ventricular diastolic function and brain natriuretic peptide (BNP) levels in patients with DDD pacemaker. Thirty patients with complete atrio-ventricular (AV) block and DDD pacemaker were included. All patients had normal left ventricular systolic function. Echocardiographic diastolic function parameters (transmitral and tissue Doppler velocities during early (E and E') and late (A and A') filling) and NT-pro-BNP levels were evaluated prospectively during atrial sensing and pacing periods. Echocardiographic data were compared with paired sample t test and NT-pro-BNP levels were compared with Wilcoxon test. Echocardiographic E/A, E'/A', E/E' ratios were calculated as 0.72+/-0.34, 0.61+/-0.21 and 8.76+/-2.58 during atrial sensing period. Same parameters were found as 0.71+/-0.23, 0.64+/-0.16 and 8.93+/-3.16 respectively during atrial pacing period. Echocardiographic left ventricular diastolic function parameters were not significantly different during atrial pacing and atrial sensing periods. Median plasma NT-pro-BNP levels were measured as 142 pg/ml (min-max 47-563 pg/ml) and 147 pg/ml (min-max 33-1035 pg/ml) during atrial sensing and pacing periods respectively. These levels were not significantly different (p=0.86). The result of this study has shown that, atrial pacing has not any additional detrimental effect on left ventricular diastolic function parameters in paced patients with normal left ventricular systolic function.

Does quantitative left ventricular regional wall motion change after fibrous tissue resection in endomyocardial fibrosis?

PubMed

Salemi, Vera Maria Cury; Fernandes, Fabio; Sirvente, Raquel; Nastari, Luciano; Rosa, Leonardo Vieira; Ferreira, Cristiano A; Pena, José Luiz Barros; Picard, Michael H; Mady, Charles

2009-01-01

We compared left ventricular regional wall motion, the global left ventricular ejection fraction, and the New York Heart Association functional class pre- and postoperatively. Endomyocardial fibrosis is characterized by fibrous tissue deposition in the endomyocardium of the apex and/or inflow tract of one or both ventricles. Although left ventricular global systolic function is preserved, patients exhibit wall motion abnormalities in the apical and inferoapical regions. Fibrous tissue resection in New York Heart Association FC III and IV endomyocardial fibrosis patients has been shown to decrease morbidity and mortality. We prospectively studied 30 patients (20 female, 30+/-10 years) before and 5+/-8 months after surgery. The left ventricular ejection fraction was determined using the area-length method. Regional left ventricular motion was measured by the centerline method. Five left ventricular segments were analyzed pre- and postoperatively. Abnormality was expressed in units of standard deviation from the mean motion in a normal reference population. Left ventricular wall motion in the five regions did not differ between pre- and postoperative measurements. Additionally, the left ventricular ejection fraction did not change after surgery (0.45+/-0.13% x 0.43+/-0.12% pre- and postoperatively, respectively). The New York Heart Association functional class improved to class I in 40% and class II in 43% of patients postoperatively (p<0.05). Although endomyocardial fibrosis patients have improved clinical symptoms after surgery, the global left ventricular ejection fraction and regional wall motion in these patients do not change. This finding suggests that other explanations, such as improvements in diastolic function, may be operational.

Correlation between cardiac remodelling, function, and myocardial contractility in rat hearts 5 weeks after myocardial infarction.

PubMed

Gosselin, H; Qi, X; Rouleau, J L

1998-01-01

Early after infarction, ventricular dysfunction occurs as a result of loss of myocardial tissue. Although papillary muscle studies suggest that reduced myocardial contractility contributes to this ventricular dysfunction, in vivo studies indicate that at rest, cardiac output is normal or near normal, suggesting that contractility of the remaining viable myocardium of the ventricular wall is preserved. However, this has never been verified. To explore this further, 100 rats with various-sized myocardial infarctions had ventricular function assessed by Langendorff preparation or by isolated papillary muscle studies 5 weeks after infarction. Morphologic studies were also done. Rats with large infarctions (54%) had marked ventricular dilatation (dilatation index from 0.23 to 0.75, p < 0.01) and papillary muscle dysfunction (total tension from 6.7 to 3.2 g/mm2, p < 0.01) but only moderate left ventricular dysfunction (maximum developed tension from 206 to 151 mmHg (1 mmHg = 133.3 Pa), p < 0.01), a decrease less than one would expect with an infarct size of 54%. The contractility of the remaining viable myocardium of the ventricle was also moderately depressed (peak systolic midwall stress 91 to 60 mmHg, p < 0.01). Rats with moderate infarctions (32%) had less marked but still moderate ventricular dilatation (dilatation index 0.37, p < 0.001) and moderate papillary muscle dysfunction (total tension 4.2 g/mm2, p < 0.01). However, their decrease in ventricular function was only mild (maximum developed pressure 178 mmHg, p < 0.01) and less than one would expect with an infarct size of 32%. The remaining viable myocardium of the ventricular wall appeared to have normal contractility (peak systolic midwall stress = 86 mmHg, ns). We conclude that in this postinfarction model, in large myocardial infarctions, a loss of contractility of the remaining viable myocardium of the ventricular wall occurs as early as 5 weeks after infarction and that papillary muscle studies slightly overestimate the degree of ventricular dysfunction. In moderate infarctions, the remaining viable myocardium of the ventricular wall has preserved contractility while papillary muscle function is depressed. In this relatively early postinfarction phase, ventricular remodelling appears to help maintain left ventricular function in both moderate and large infarctions.

Comparison of the survival between coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with poor left ventricular function (ejection fraction <30%): a propensity-matched analysis.

PubMed

Shah, Shaneel; Benedetto, Umberto; Caputo, Massimo; Angelini, Gianni D; Vohra, Hunaid A

2018-06-22

Existing evidence comparing the outcomes of coronary artery bypass graft (CABG) surgery versus percutaneous coronary intervention (PCI) in patients with poor left ventricular function (LVF) is sparse and flawed. This is largely due to patients with poor LVF being underrepresented in major research trials and the outdated nature of some studies that do not consider drug-eluting stent PCI. Following strict inclusion criteria, 717 patients who underwent revascularization by CABG or PCI between 2002 and 2015 were enrolled. All patients had poor LVF (defined by ejection fraction <30%). By employing a propensity score analysis, 134 suitable matches (67 CABG and 67 PCI) were identified. Several outcomes were evaluated, in the matched population, using data extracted from national registry databases. CABG patients required a longer length of hospital stay post-revascularization compared to PCI in the propensity-matched population, 7 days (lower-upper quartile; 6-12) and 2 days (lower-upper quartile; 1-6), respectively (Mood's median test, P = 0.001). Stratified Cox-regression proportional-hazards analysis of the propensity-matched population found that PCI patients experienced a higher adjusted 8-year mortality rate (hazard ratio 3.291, 95% confidence interval 1.776-6.101; P < 0.001). This trend was consistent amongst urgent cases of revascularization: patients with 3 or more vessels with coronary artery disease and patients where complete revascularization was achieved. Although sub-analyses found no difference between survival distributions of on-pump versus off-pump CABG (log-rank P = 0.726), both modes of CABG were superior to PCI (stratified log-rank P = 0.002). Despite a longer length of hospital stay, patients with impaired LVF requiring intervention for coronary artery disease experienced a greater post-procedural survival benefit if they received CABG compared to PCI. We have demonstrated this at 30 days, 90 days, 1 year, 3 years, 5 years and 8 years following revascularization. At present, CABG remains a superior revascularization modality to PCI in patients with poor LVF.

Continuous-Flow Left Ventricular Assist Device Support Improves Myocardial Supply:Demand in Chronic Heart Failure.

PubMed

Soucy, Kevin G; Bartoli, Carlo R; Phillips, Dustin; Giridharan, Guruprasad A; Sobieski, Michael A; Wead, William B; Dowling, Robert D; Wu, Zhongjun J; Prabhu, Sumanth D; Slaughter, Mark S; Koenig, Steven C

2017-06-01

Continuous-flow left ventricular assist devices (CF LVADs) are rotary blood pumps that improve mean blood flow, but with potential limitations of non-physiological ventricular volume unloading and diminished vascular pulsatility. In this study, we tested the hypothesis that left ventricular unloading with increasing CF LVAD flow increases myocardial flow normalized to left ventricular work. Healthy (n = 8) and chronic ischemic heart failure (IHF, n = 7) calves were implanted with CF LVADs. Acute hemodynamics and regional myocardial blood flow were measured during baseline (LVAD off, clamped), partial (2-4 L/min) and full (>4 L/min) LVAD support. IHF calves demonstrated greater reduction of cardiac energy demand with increasing LVAD support compared to healthy calves, as calculated by rate-pressure product. Coronary artery flows (p < 0.05) and myocardial blood flow (left ventricle (LV) epicardium and myocardium, p < 0.05) decreased with increasing LVAD support in normal calves. In the IHF model, blood flow to the septum, LV, LV epicardium, and LV myocardium increased significantly with increasing LVAD support when normalized to cardiac energy demand (p < 0.05). In conclusion, myocardial blood flow relative to cardiac demand significantly increased in IHF calves, thereby demonstrating that CF LVAD unloading effectively improves cardiac supply and demand ratio in the setting of ischemic heart failure.

Regional effects of streptozotocin-induced diabetes on shortening and calcium transport in epicardial and endocardial myocytes from rat left ventricle.

PubMed

Smail, Manal M A; Qureshi, Muhammad A; Shmygol, Anatoliy; Oz, Murat; Singh, Jaipaul; Sydorenko, Vadym; Arabi, Alya; Howarth, Frank C; Al Kury, Lina

2016-11-01

In the heart, the left ventricle pumps blood at higher pressure than the right ventricle. Within the left ventricle, the electromechanical properties of ventricular cardiac myocytes vary transmurally and this may be related to the gradients of stress and strain experienced in vivo across the ventricular wall. Diabetes is also associated with alterations in hemodynamic function. The aim of this study was to investigate shortening and Ca 2+ transport in epicardial (EPI) and endocardial (ENDO) left ventricular myocytes in the streptozotocin (STZ)-induced diabetic rat. Shortening, intracellular Ca 2+ and L-type Ca 2+ current (I Ca,L ) were measured by video detection, fura-2 microfluorimetry, and whole-cell patch clamp techniques, respectively. Time to peak (TPK) shortening was prolonged to similar extents in ENDO and EPI myocytes from STZ-treated rats compared to ENDO and EPI myocytes from controls. Time to half (THALF) relaxation of shortening was prolonged in ENDO myocytes from STZ-treated rats compared to ENDO controls. TPK Ca 2+ transient was prolonged in ENDO myocytes from STZ-treated rats compared to ENDO controls. THALF decay of the Ca 2+ transient was prolonged in ENDO myocytes from STZ-treated rats compared to ENDO controls. Sarcoplasmic reticulum (SR) fractional release of Ca 2+ was reduced in EPI myocytes from STZ-treated rats compared to EPI controls. I C a,L activation, inactivation, and recovery from inactivation were not significantly altered in EPI and ENDO myocytes from STZ-treated rats or controls. Regional differences in Ca 2+ transport may partly underlie differences in ventricular myocyte shortening across the wall of the healthy and the STZ-treated rat left ventricle. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Radionuclide evaluation of left ventricular function with nonimaging probes.

PubMed

Wexler, J P; Blaufox, M D

1979-10-01

Portable nonimaging probes have been developed that can evaluate left ventricular function using radionuclide techniques. Two modes of data acquisition are possible with these probe systems, first-pass and gated. Precordial radiocardiograms obtained after a bolus injection can be used to determine cardiac output, pulmonary transit time, pulmonary blood volume, left ventricle ejection fraction, and left-to-right shunts. Gated techniques can be used to determine left ventricular ejection fraction and sytolic time intervals. Probe-determined indices of left ventricular function agree excellently with comparable measurements determined by conventional camera-computer methods as well as by invasive techniques. These have begun to be used in a preliminary manner in a variety of clinical problems associated with left ventricular dysfunction. This review discusses the types of probe systems available, the methods used in positioning them, and details the specifics of their data acquisition and processing capacity. The major criticisms of probe methods are that they are nonimaging and that they measure global rather than regional left ventricular function. In spite of these criticisms, probe systems, because of their portability, high sensitivity, and relatively low cost are useful supplements to conventional camera-computer systems for the measurement of parameters of left ventricular performance using radionuclide techniques.

Atrioventricular valve repair in patients with functional single-ventricle physiology: impact of ventricular and valve function and morphology on survival and reintervention.

PubMed

Honjo, Osami; Atlin, Cori R; Mertens, Luc; Al-Radi, Osman O; Redington, Andrew N; Caldarone, Christopher A; Van Arsdell, Glen S

2011-08-01

This study was to determine whether atrioventricular valve repair modifies natural history of single-ventricle patients with atrioventricular valve insufficiency and to identify factors predicting survival and reintervention. Fifty-seven (13.5%) of 422 single-ventricle patients underwent atrioventricular valve repair. Valve morphology, regurgitation mechanism, and ventricular morphology and function were analyzed for effect on survival, transplant, and reintervention with multivariate logistic and Cox regression models. Comparative analysis used case-matched controls. Atrioventricular valve was tricuspid in 67% and common in 28%. Ventricular morphology was right in 83%. Regurgitation mechanisms were prolapse (n = 24, 46%), dysplasia (n = 18, 35%), annular dilatation (n = 8, 15%), and restriction or cleft (n = 2, 4%). Postrepair insufficiency was none or trivial in 14 (26%), mild in 33 (61%), and moderate in 7 (13%). Survival in repair group was lower than in matched controls (78.9% vs 92.7% at 1 year, 68.7% vs 90.6% at 3 years, P = .015). Patients with successful repair and normal ventricular function had equivalent survival to matched controls (P = .36). Independent predictors for death or transplant included increased indexed annular size (P = .05), increased cardiopulmonary bypass time (P = .04), and decreased postrepair ventricular function (P = .01). Ventricular dilation was a time-related factor for all events, including failed repair. Survival was lower in single-ventricle patients operated on for atrioventricular valve insufficiency than in case-matched controls. Patients with little postoperative residual regurgitation and preserved ventricular function had equivalent survival to controls. Lower grade ventricular function and ventricular dilation correlated with death and repair failure, suggesting that timing of intervention may affect outcome. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Development of mechanical circulatory support devices in China.

PubMed

Wang, Wei; Zhu, De-Ming; Ding, Wen-Xiang

2009-11-01

Myocardial dysfunction leading to low cardiac output syndrome is a common clinical pathophysiological state. Currently, the use of mechanical circulatory support (MCS) is an essential aspect of the treatment of patients with cardiac failure. Several groups in China are engaged in the design and development of MCS devices. These devices can be classified as pulsatile, rotary, and total artificial heart (TAH). There are two types of pulsatile pump, which are driven by air (pneumatic). One of these pumps, the Luo-Ye pump, has been used clinically for short-term support since 1998. The other is a push-plate left ventricular device, which has a variable rate mode. Various rotary devices are classified into axial and centrifugal pumps, depending on the impeller geometry. Most rotary pumps are based on the maglev principle, and some types have been used clinically. Others are still being studied in the laboratory or in animal experiments. Furthermore, certain types of total implantable pump, such as the UJS-III axial pump and the UJS-IV aortic valvo-pump, have been developed. Only one type of TAH has been developed in China. The main constituents of this artificial heart are two axial pumps, two reservoir tanks mimicking the right and left atria, flow meters, two pressure gauges, and a resistance adaptor. Although the development of mechanical assist devices in China is still in a nascent stage, a number of different types of MCS devices are currently being studied.

Implantable physiologic controller for left ventricular assist devices with telemetry capability.

PubMed

Asgari, Siavash S; Bonde, Pramod

2014-01-01

Rotary type left ventricular assist devices have mitigated the problem of durability associated with earlier pulsatile pumps and demonstrated improved survival. However, the compromise is the loss of pulsatility due to continuous flow and retained percutaneous driveline leading to increased mortality and morbidity. Lack of pulsatility is implicated in increased gastrointestinal bleeding, aortic incompetence, and diastolic hypertension. We present a novel, wirelessly powered, ultra-compact, implantable physiologic controller capable of running a left ventricular assist device in a pulsatile mode with wireless power delivery. The schematic of our system was laid out on a circuit board to wirelessly receive power and run a left ventricular assist device with required safety and backup measures. We have embedded an antenna and wireless network for telemetry. Multiple signal processing steps and controlling algorithm were incorporated. The controller was tested in in vitro and in vivo experiments. The controller drove left ventricular assist devices continuously for 2 weeks in an in vitro setup and in vivo without any failure. Our controller is more power efficient than the current Food and Drug Administration-approved left ventricular assist device controllers. When used with electrocardiography synchronization, the controller allowed on-demand customization of operation with instantaneous flow and revolutions per minute changes, resulting in a pulsatile flow with adjustable pulse pressure. Our test results prove the system to be remarkably safe, accurate, and efficient. The unique combination of wireless powering and small footprint makes this system an ideal totally implantable physiologic left ventricular assist device system. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Population of computational rabbit-specific ventricular action potential models for investigating sources of variability in cellular repolarisation.

PubMed

Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T Alexander

2014-01-01

Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+), inward rectifying K(+), L-type Ca(2+), and Na(+)/K(+) pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally observed intercellular variability of rabbit ventricular action potential repolarisation.

Population of Computational Rabbit-Specific Ventricular Action Potential Models for Investigating Sources of Variability in Cellular Repolarisation

PubMed Central

Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T. Alexander

2014-01-01

Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K+, inward rectifying K+, L-type Ca2+, and Na+/K+ pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally observed intercellular variability of rabbit ventricular action potential repolarisation. PMID:24587229

Simulation based efficiency prediction of a Brushless DC drive applied in ventricular assist devices.

PubMed

Pohlmann, André; Hameyer, Kay

2012-01-01

Ventricular Assist Devices (VADs) are mechanical blood pumps that support the human heart in order to maintain a sufficient perfusion of the human body and its organs. During VAD operation blood damage caused by hemolysis, thrombogenecity and denaturation has to be avoided. One key parameter causing the blood's denaturation is its temperature which must not exceed 42 °C. As a temperature rise can be directly linked to the losses occuring in the drive system, this paper introduces an efficiency prediction chain for Brushless DC (BLDC) drives which are applied in various VAD systems. The presented chain is applied to various core materials and operation ranges, providing a general overview on the loss dependencies.

Can the epirubicin cardiotoxicity in cancer patients be prevented by angiotensin converting enzyme inhibitors?

PubMed

Radulescu, D; Buzdugan, E; Ciuleanu, T E; Todor, N; Stoicescu, L

2013-01-01

The aim of this study was to assess whether treatment with angiotensin converting enzyme inhibitors (ACEI) can prevent the alteration of left ventricular systolic and diastolic performance in cancer patients treated with different chemotherapy regimens containing epirubicin. In this prospective study , 68 patients with different malignant tumors treated with epirubicin and perindopril in different chemotherapy protocols (study group), and a gender- and age-matched group of 68 patients with different malignant tumors treated with epirubicin without perindopril in different chemotherapy protocols (control group), were assessed by Doppler echocardiography. Left ventricular systolic function was assessed by measuring left ventricular ejection fraction (EF). Left ventricular diastolic function was assessed by Doppler ultrasound by evaluating the transmitral flow. We also assessed the QTc on the 12 lead electrocardiograms. At the end of chemotherapy the left ventricular systolic function was less altered in the study group compared to the control group and was superior in the study group (epirubicin+ACEI) compared to the control group (epirubicin alone). We documented a significantly deteriorated left ventricular diastolic function in both groups at the completion of chemotherapy. QTc time in both arms was also significantly prolonged. In the present echo-Doppler study we documented a preserved left ventricular systolic performance in patients with various malignancies treated with epirubicin plus perindopril. Although co-treatment with ACEI prevented the alteration of systolic performance, it failed to prevent the deterioration of the left ventricular diastolic performance impairment due to poor left ventricular compliance.

High-Intensity Interval Training for Severe Left Ventricular Dysfunction Treated with Left Ventricular Assist Device.

PubMed

Ugata, Yusuke; Wada, Hiroshi; Sakakura, Kenichi; Ibe, Tatsuro; Ito, Miyuki; Ikeda, Nahoko; Fujita, Hideo; Momomura, Shin-Ichi

2018-01-27

Aerobic training based on anaerobic threshold (AT) is well-known to improve cardiac function, exercise capacity, and long-term outcomes of patients with heart failure. Recent reports suggested that high-intensity interval training (HIIT) for patients with cardiovascular disease may improve cardiopulmonary exercise capacity. We present a 61-year-old male patient of severe left ventricular dysfunction with left ventricular assisted device (LVAD). Following HIIT for 8 weeks, exercise capacity and muscle strength have improved without worsening left ventricular function. Our case showed the possibility that HIIT was feasible and effective even in patients with LVAD.

Changes in renal function after implantation of continuous-flow left ventricular assist devices.

PubMed

Hasin, Tal; Topilsky, Yan; Schirger, John A; Li, Zhuo; Zhao, Yanjun; Boilson, Barry A; Clavell, Alfredo L; Rodeheffer, Richard J; Frantz, Robert P; Edwards, Brooks S; Pereira, Naveen L; Joyce, Lyle; Daly, Richard; Park, Soon J; Kushwaha, Sudhir S

2012-01-03

The aim of this study was to determine renal outcomes after left ventricular assist device (LVAD) implantation. Renal dysfunction before LVAD placement is frequent, and it is unclear whether it is due to primary renal disease or to poor perfusion. A retrospective single-center analysis was conducted in 83 consecutive patients implanted with HeartMate II continuous-flow LVADs (Thoratec Corp., Pleasanton, California). Calculated glomerular filtration rate (GFR) was assessed on admission and 1, 3, and 6 months after implantation. To define predictors for improvement in GFR, clinical variables were examined in patients with decreased renal function (GFR <60 ml/min/1.73 m(2)) before LVAD, surviving and dialysis-free at 1 month (n = 44). GFR significantly increased from admission (53.2 ± 21.4 ml/min/1.73 m(2)) to 1 month after LVAD implantation (87.4 ± 27.9 ml/min/1.73 m(2)) (p < 0.0001). Subsequently, at 3 and 6 months, GFR remained significantly (p < 0.0001) above pre-LVAD values. Of the 51 patients with GFRs <60 ml/min/1.73 m(2) before LVAD surviving at 1 month, 34 (67%) improved to GFRs >60 ml/min/1.73 m(2). Univariate pre-operative predictors for improvement in renal function at 1 month included younger age (p = 0.049), GFR improvement with optimal medical therapy (p < 0.001), intra-aortic balloon pump use (p = 0.004), kidney length above 10 cm (p = 0.023), no treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (p = 0.029), higher bilirubin (p = 0.002), higher Lietz-Miller score (p = 0.019), and atrial fibrillation (p = 0.007). Multivariate analysis indicated pre-operative improved GFR (slope = 0.5 U per unit improved; 95% confidence interval: 0.2 to 0.8; p = 0.003), atrial fibrillation (slope = 27; 95% confidence interval: 8 to 46; p = 0.006), and intra-aortic balloon pump use (slope = 14; 95% confidence interval: 2 to 26; p = 0.02) as independent predictors. In most patients with end-stage heart failure considered for LVAD implantation, renal dysfunction is reversible and likely related to poor renal perfusion. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

A computer model of the pediatric circulatory system for testing pediatric assist devices.

PubMed

Giridharan, Guruprasad A; Koenig, Steven C; Mitchell, Michael; Gartner, Mark; Pantalos, George M

2007-01-01

Lumped parameter computer models of the pediatric circulatory systems for 1- and 4-year-olds were developed to predict hemodynamic responses to mechanical circulatory support devices. Model parameters, including resistance, compliance and volume, were adjusted to match hemodynamic pressure and flow waveforms, pressure-volume loops, percent systole, and heart rate of pediatric patients (n = 6) with normal ventricles. Left ventricular failure was modeled by adjusting the time-varying compliance curve of the left heart to produce aortic pressures and cardiac outputs consistent with those observed clinically. Models of pediatric continuous flow (CF) and pulsatile flow (PF) ventricular assist devices (VAD) and intraaortic balloon pump (IABP) were developed and integrated into the heart failure pediatric circulatory system models. Computer simulations were conducted to predict acute hemodynamic responses to PF and CF VAD operating at 50%, 75% and 100% support and 2.5 and 5 ml IABP operating at 1:1 and 1:2 support modes. The computer model of the pediatric circulation matched the human pediatric hemodynamic waveform morphology to within 90% and cardiac function parameters with 95% accuracy. The computer model predicted PF VAD and IABP restore aortic pressure pulsatility and variation in end-systolic and end-diastolic volume, but diminish with increasing CF VAD support.

Myoarchitecture and connective tissue in hearts with tricuspid atresia

PubMed Central

Sanchez-Quintana, D; Climent, V; Ho, S; Anderson, R

1999-01-01

Objective—To compare the atrial and ventricular myoarchitecture in the normal heart and the heart with tricuspid atresia, and to investigate changes in the three dimensional arrangement of collagen fibrils.
Methods—Blunt dissection and cell maceration with scanning electron microscopy were used to study the architecture of the atrial and ventricular musculature and the arrangement of collagen fibrils in three specimens with tricuspid atresia and six normal human hearts.
Results—There were significant modifications in the myoarchitecture of the right atrium and the left ventricle, both being noticeably hypertrophied. The middle layer of the ventricle in the abnormal hearts was thicker than in the normal hearts. The orientation of the superficial layer in the left ventricle in hearts with tricuspid atresia was irregular compared with the normal hearts. Scanning electron microscopy showed coarser endomysial sheaths and denser perimysial septa in hearts with tricuspid atresia than in normal hearts.
Conclusions—The overall architecture of the muscle fibres and its connective tissue matrix in hearts with tricuspid atresia differed from normal, probably reflecting modelling of the myocardium that is inherent to the malformation. This is in concordance with clinical observations showing deterioration in pump function of the dominant left ventricle from very early in life.

 Keywords: tricuspid atresia; congenital heart defects; connective tissue; fibrosis PMID:9922357

Mending a Broken Heart: Treatment of Stress-Induced Heart Failure after Solid Organ Transplantation

PubMed Central

Kumm, Kayla; Kueht, Michael; Ha, Cindy P.; Yoeli, Dor; Cotton, Ronald T.; Rana, Abbas; O'Mahony, Christine A.; Halff, Glenn; Goss, John A.

2018-01-01

Stress-induced heart failure, also known as Broken Heart Syndrome or Takotsubo Syndrome, is a phenomenon characterized as rare but well described in the literature, with increasing incidence. While more commonly associated with postmenopausal women with psychiatric disorders, this entity is found in the postoperative patient. The nonischemic cardiogenic shock manifests as biventricular failure with significant decreases in ejection fraction and cardiac function. In a review of over 3000 kidney and liver transplantations over the course of 17 years within two transplant centers, we describe a series of 7 patients with Takotsubo Syndrome after solid organ transplantation. Furthermore, we describe a novel approach of successfully treating the transient, though potentially fatal, cardiogenic shock with a percutaneous ventricular assistance device in two liver transplant patients, while treating one kidney transplant patient medically and the remaining four liver transplant patients with an intra-aortic balloon pump. We describe our experience with Takotsubo's Syndrome and compare the three modalities of treatment and cardiac augmentation. Our series is novel in introducing the percutaneous ventricular assist device as a more minimally invasive intervention in treating nonischemic heart failure in the solid organ transplant patient, while serving as a comprehensive overview of treatment modalities for stress-induced heart failure. PMID:29670765

Presence of reduced regional left ventricular function even in the absence of left ventricular wall scar tissue in the long term after repair of an anomalous left coronary artery from the pulmonary artery.

PubMed

Nordmeyer, Sarah; Schmitt, Boris; Nasseri, Boris; Alexi-Meskishvili, Vladimir; Kuehne, Titus; Berger, Felix; Nordmeyer, Johannes

2018-02-01

We sought to assess left ventricular regional function in patients with and without left ventricular wall scar tissue in the long term after repair of an anomalous origin of the left coronary artery from the pulmonary artery. A total of 20 patients aged 12.8±7.4 years were assessed 10 (0.5-17) years after the repair of an anomalous origin of the left coronary artery from the pulmonary artery; of them, 10 (50%) patients showed left ventricular wall scar tissue on current cardiac MRI. Left ventricular regional function was assessed by two-dimensional speckle-tracking echocardiography in 10 patients with scar tissue and 10 patients without scar tissue and in 10 age-matched controls. In patients with scar tissue, MRI-derived left ventricular ejection fraction was significantly reduced compared with that in patients without scar tissue (51 versus 61%, p<0.05), and echocardiography-derived longitudinal strain was significantly reduced in five of six left ventricular areas compared with that in healthy controls (average relative reduction, 46%; p<0.05). In patients without scar tissue, longitudinal strain was significantly reduced in two of six left ventricular areas (average relative reduction, 23%; p<0.05) and circumferential strain was reduced in one of six left ventricular areas (relative reduction, 56%; p<0.05) compared with that in healthy controls. Regional left ventricular function is reduced even in patients without left ventricular wall scar tissue late after successful repair of an anomalous origin of the left coronary artery from the pulmonary artery. This highlights the need for meticulous lifelong follow-up in all patients with a repaired anomalous origin of the left coronary artery from the pulmonary artery.

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

PubMed

Tedoriya, T; Kawasuji, M; Sakakibara, N; Takemura, H; Watanabe, Y; Hetzer, R

1998-08-01

Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

Papillary Muscle Repositioning as a Subvalvular Apparatus Preservation Technique in Mitral Stenosis Patients with Normal Left Ventricular Systolic Function

PubMed Central

Lafci, Gokhan; Cagli, Kerim; Korkmaz, Kemal; Turak, Osman; Uzun, Alper; Yalcinkaya, Adnan; Diken, Adem; Gunertem, Eren; Cagli, Kumral

2014-01-01

Subvalvular apparatus preservation is an important concept in mitral valve replacement (MVR) surgery that is performed to remedy mitral regurgitation. In this study, we sought to determine the effects of papillary muscle repositioning (PMR) on clinical outcomes and echocardiographic left ventricular function in rheumatic mitral stenosis patients who had normal left ventricular systolic function. We prospectively assigned 115 patients who were scheduled for MVR surgery with mechanical prosthesis to either PMR or MVR-only groups. Functional class and echocardiographic variables were evaluated at baseline and at early and late postoperative follow-up examinations. All values were compared between the 2 groups. The PMR group consisted of 48 patients and the MVR-only group of 67 patients. The 2 groups’ baseline characteristics and surgery-related factors (including perioperative mortality) were similar. During the 18-month follow-up, all echocardiographic variables showed a consistent improvement in the PMR group; the mean left ventricular ejection fraction deteriorated significantly in the MVR-only group. Comparison during follow-up of the magnitude of longitudinal changes revealed that decreases in left ventricular end-diastolic and end-systolic diameters and in left ventricular sphericity indices, and increases in left ventricular ejection fractions, were significantly higher in the PMR group than in the MVR-only group. This study suggests that, in patients with rheumatic mitral stenosis and preserved left ventricular systolic function, the addition of papillary muscle repositioning to valve replacement with a mechanical prosthesis improves left ventricular dimensions, ejection fraction, and sphericity index at the 18-month follow-up with no substantial undesirable effect on the surgery-related factors. PMID:24512397

A linear motor and compact cylinder-piston driver for left ventricular bypass.

PubMed

Qian, K X

1990-01-01

A simple, portable, reliable and noise-free pneumatic driver has been developed. It consists of a linear motor attached to a cylinder piston, in one unit. The motor coil is directly wound on the cylinder, and the permanent magnet is fixed to the piston. As a continuous voltage square wave is applied to the coil, the cylinder reciprocates on the piston periodically, producing air pressure and vacuum alternately. In conjunction with a locally made diaphragm pump, the driver was tested in vitro and in vivo. Results demonstrated that the device could drive the diaphragm pump and so support the circulation of an experimental animal. The driver weighs 12 kg. For 200 mmHg air pressure and -80 mmHg vacuum the power consumed is 30 W. Its noise is about 30 dB, less than that of an artificial valve and pump.

"Reversibility of Cardiovascular Injury With CPAP Use: Mechanisms Involved"

ClinicalTrials.gov

2015-09-29

Sleep Apnea, Obstructive; Hypoxia; Hypercapnia; Sleep Disorders; Obesity; Hypertension; Coronary Artery Vasospasm; Right Ventricular Overload; Left Ventricular Function Systolic Dysfunction; Ventricular Hypertrophy

No drive line, no seal, no bearing and no wear: magnetics for impeller suspension and flow assessment in a new VAD.

PubMed

Huber, Christoph H; Tozzi, Piergiorgio; Hurni, Michel; von Segesser, Ludwig K

2004-06-01

The new magnetically suspended axial pump is free of seals, bearings, mechanical friction and wear. In the absence of a drive shaft or flow meter, pump flow assessment is made with an algorithm based on currents required for impeller rotation and stabilization. The aim of this study is to validate pump performance, algorithm-based flow and effective flow. A series of bovine experiments was realized after equipment with pressure transducers, continuous-cardiac-output-catheter, intracardiac ultrasound (AcuNav) over 6 h. Pump implantation was through a median sternotomy (LV-->VAD-->calibrated transonic-flow-probe-->aorta). A transonic-HT311-flow-probe was fixed onto the outflow cannula for flow comparison. Animals were electively sacrificed and at necropsy systematic pump inspection and renal embolus score was realized. Observation period was 340+/-62.4 min. The axial pump generated a mean arterial pressure of 58.8+/-14.3 mmHg (max 117 mmHg) running at a speed of 6591.3+/-1395.4 rev./min (min 5000/max 8500 rev./min) and generating 2.5+/-1.0 l/min (min 1.4/max 6.0 l/min) of flow. Correlation between the results of the pump flow algorithm and measured pump flow was linear (y=1.0339x, R2=0.9357). VAD explants were free of macroscopic thrombi. Renal embolus score was 0+/-0. The magnetically suspended axial flow pump provides excellent left ventricular support. The pump flow algorithm used is accurate and reliable. Therefore, there is no need for direct flow measurement.

A Separate Pool of Cardiac Phospholemman That Does Not Regulate or Associate with the Sodium Pump

PubMed Central

Wypijewski, Krzysztof J.; Howie, Jacqueline; Reilly, Louise; Tulloch, Lindsay B.; Aughton, Karen L.; McLatchie, Linda M.; Shattock, Michael J.; Calaghan, Sarah C.; Fuller, William

2013-01-01

Phospholemman (PLM), the principal quantitative sarcolemmal substrate for protein kinases A and C in the heart, regulates the cardiac sodium pump. Much like phospholamban, which regulates the related ATPase SERCA, PLM is reported to oligomerize. We investigated subpopulations of PLM in adult rat ventricular myocytes based on phosphorylation status. Co-immunoprecipitation identified two pools of PLM: one not associated with the sodium pump phosphorylated at Ser63 and one associated with the pump, both phosphorylated at Ser68 and unphosphorylated. Phosphorylation of PLM at Ser63 following activation of PKC did not abrogate association of PLM with the pump, so its failure to associate with the pump was not due to phosphorylation at this site. All pools of PLM co-localized to cell surface caveolin-enriched microdomains with sodium pump α subunits, despite the lack of caveolin-binding motif in PLM. Mass spectrometry analysis of phosphospecific immunoprecipitation reactions revealed no unique protein interactions for Ser63-phosphorylated PLM, and cross-linking reagents also failed to identify any partner proteins for this pool. In lysates from hearts of heterozygous transgenic animals expressing wild type and unphosphorylatable PLM, Ser63-phosphorylated PLM co-immunoprecipitated unphosphorylatable PLM, confirming the existence of PLM multimers. Dephosphorylation of the PLM multimer does not change sodium pump activity. Hence like phospholamban, PLM exists as a pump-inhibiting monomer and an unassociated oligomer. The distribution of different PLM phosphorylation states to different pools may be explained by their differential proximity to protein phosphatases rather than a direct effect of phosphorylation on PLM association with the pump. PMID:23532852

Computational prediction of hemolysis in a centrifugal ventricular assist device.

PubMed

Pinotti, M; Rosa, E S

1995-03-01

This paper describes the use of computational fluid dynamics (CFD) to predict numerically the hemolysis in centrifugal pumps. A numerical hydrodynamical model, based on the full Navier-Stokes equation, was used to obtain the flow in a vaneless centrifugal pump (of corotating disks type). After proper postprocessing, critical zones in the channel were identified by means of two-dimensional color-coded maps of %Hb release. Simulation of different conditions revealed that flow behavior at the entrance region of the channel is the main cause of blood trauma in such devices. A useful feature resulting from the CFD simulation is the visualization of critical flow zones that are impossible to determine experimentally with in vitro hemolysis tests.

Investigating the Role of Interventricular Interdependence in Development of Right Heart Dysfunction During LVAD Support: A Patient-Specific Methods-Based Approach.

PubMed

Sack, Kevin L; Dabiri, Yaghoub; Franz, Thomas; Solomon, Scott D; Burkhoff, Daniel; Guccione, Julius M

2018-01-01

Predictive computation models offer the potential to uncover the mechanisms of treatments whose actions cannot be easily determined by experimental or imaging techniques. This is particularly relevant for investigating left ventricular mechanical assistance, a therapy for end-stage heart failure, which is increasingly used as more than just a bridge-to-transplant therapy. The high incidence of right ventricular failure following left ventricular assistance reflects an undesired consequence of treatment, which has been hypothesized to be related to the mechanical interdependence between the two ventricles. To investigate the implication of this interdependence specifically in the setting of left ventricular assistance device (LVAD) support, we introduce a patient-specific finite-element model of dilated chronic heart failure. The model geometry and material parameters were calibrated using patient-specific clinical data, producing a mechanical surrogate of the failing in vivo heart that models its dynamic strain and stress throughout the cardiac cycle. The model of the heart was coupled to lumped-parameter circulatory systems to simulate realistic ventricular loading conditions. Finally, the impact of ventricular assistance was investigated by incorporating a pump with pressure-flow characteristics of an LVAD (HeartMate II™ operating between 8 and 12 k RPM) in parallel to the left ventricle. This allowed us to investigate the mechanical impact of acute left ventricular assistance at multiple operating-speeds on right ventricular mechanics and septal wall motion. Our findings show that left ventricular assistance reduces myofiber stress in the left ventricle and, to a lesser extent, right ventricle free wall, while increasing leftward septal-shift with increased operating-speeds. These effects were achieved with secondary, potentially negative effects on the interventricular septum which showed that support from LVADs, introduces unnatural bending of the septum and with it, increased localized stress regions. Left ventricular assistance unloads the left ventricle significantly and shifts the right ventricular pressure-volume-loop toward larger volumes and higher pressures; a consequence of left-to-right ventricular interactions and a leftward septal shift. The methods and results described in the present study are a meaningful advancement of computational efforts to investigate heart-failure therapies in silico and illustrate the potential of computational models to aid understanding of complex mechanical and hemodynamic effects of new therapies.

Surgical myocardial revascularization in patients with reduced systolic left ventricular function.

PubMed

Bruno, Piergiorgio; Iafrancesco, Mauro; Massetti, Massimo

2018-04-20

Surgical myocardial revascularization in patients with reduced left ventricular function has been a matter of debate for decades. Recently published 10-years extension follow-up of the STICH trial have conclusively demonstrated benefit of surgical myocardial revascularization in patients with significant coronary artery disease and low left ventricular ejection fraction. However, selection of patients for surgery remains challenging as well as decision to perform percutaneous rather than surgical revascularization in this class of patients. New evidence helped to clarify the role of preoperative patients' characteristics as risk factors for surgery and to identify those patients who may benefit the most from surgery. Focus of this review is to review epidemiology, aetiology and pathophysiology of coronary artery disease in patients with reduced left ventricular function, role of viability and results of observational and investigational studies on revascularization in patients with reduced left ventricular function with a particular emphasis on relative indication of coronary artery bypass grafting and percutaneous coronary intervention and the surgical implications of development of ischemic mitral regurgitation or ischemic left ventricular aneurysm.

The left ventricle in aortic stenosis--imaging assessment and clinical implications.

PubMed

Călin, Andreea; Roşca, Monica; Beladan, Carmen Cristiana; Enache, Roxana; Mateescu, Anca Doina; Ginghină, Carmen; Popescu, Bogdan Alexandru

2015-04-29

Aortic stenosis has an increasing prevalence in the context of aging population. In these patients non-invasive imaging allows not only the grading of valve stenosis severity, but also the assessment of left ventricular function. These two goals play a key role in clinical decision-making. Although left ventricular ejection fraction is currently the only left ventricular function parameter that guides intervention, current imaging techniques are able to detect early changes in LV structure and function even in asymptomatic patients with significant aortic stenosis and preserved ejection fraction. Moreover, new imaging parameters emerged as predictors of disease progression in patients with aortic stenosis. Although proper standardization and confirmatory data from large prospective studies are needed, these novel parameters have the potential of becoming useful tools in guiding intervention in asymptomatic patients with aortic stenosis and stratify risk in symptomatic patients undergoing aortic valve replacement.This review focuses on the mechanisms of transition from compensatory left ventricular hypertrophy to left ventricular dysfunction and heart failure in aortic stenosis and the role of non-invasive imaging assessment of the left ventricular geometry and function in these patients.

Mechanical circulatory support of a univentricular Fontan circulation with a continuous axial-flow pump in a piglet model.

PubMed

Wei, Xufeng; Sanchez, Pablo G; Liu, Yang; Li, Tieluo; Watkins, A Claire; Wu, Zhongjun J; Griffith, Bartley P

2015-01-01

Despite the significant contribution of the Fontan procedure to the therapy of complex congenital heart diseases, many patients progress to failure of their Fontan circulation. The use of ventricular assist devices to provide circulatory support to these patients remains challenging. In the current study, a continuous axial-flow pump was used to support a univentricular Fontan circulation. A modified Fontan circulation (atrio-pulmonary connection) was constructed in six Yorkshire piglets (8-14 kg). A Dacron conduit (12 mm) with two branches was constructed to serve as a complete atrio-pulmonary connection without the use of cardiopulmonary bypass. The Impella pump was inserted into the conduit through an additional Polytetrafluoroethylene (PTFE) graft in five animals. Hemodynamic data were collected for 6 hours under the supported Fontan circulation. The control animal died after initiating the Fontan circulation independent of resuscitation. Four pump supported animals remained hemodynamically stable for 6 hours with pump speeds between 18,000 rpm and 22,000 rpm (P1-P3). Oxygen saturation was maintained between 95% and 100%. Normal organ perfusion was illustrated by blood gas analysis and biochemical assays. A continuous axial-flow pump can be used for temporal circulatory support to the failing Fontan circulation as "bridge" to heart transplantation or recovery.

Optimization of a miniature Maglev ventricular assist device for pediatric circulatory support.

PubMed

Zhang, Juntao; Koert, Andrew; Gellman, Barry; Gempp, Thomas M; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

2007-01-01

A miniature Maglev blood pump based on magnetically levitated bearingless technology is being developed and optimized for pediatric patients. We performed impeller optimization by characterizing the hemodynamic and hemocompatibility performances using a combined computational and experimental approach. Both three-dimensional flow features and hemolytic characteristics were analyzed using computational fluid dynamics (CFD) modeling. Hydraulic pump performances and hemolysis levels of three different impeller designs were quantified and compared numerically. Two pump prototypes were constructed from the two impeller designs and experimentally tested. Comparison of CFD predictions with experimental results showed good agreement. The optimized impeller remarkably increased overall pump hydraulic output by more than 50% over the initial design. The CFD simulation demonstrated a clean and streamlined flow field in the main flow path. The numerical results by hemolysis model indicated no significant high shear stress regions. Through the use of CFD analysis and bench-top testing, the small pediatric pump was optimized to achieve a low level of blood damage and improved hydraulic performance and efficiency. The Maglev pediatric blood pump is innovative due to its small size, very low priming volume, excellent hemodynamic and hematologic performance, and elimination of seal-related and bearing-related failures due to adoption of magnetically levitated bearingless motor technology, making it ideal for pediatric applications.

Atlas-Based Ventricular Shape Analysis for Understanding Congenital Heart Disease.

PubMed

Farrar, Genevieve; Suinesiaputra, Avan; Gilbert, Kathleen; Perry, James C; Hegde, Sanjeet; Marsden, Alison; Young, Alistair A; Omens, Jeffrey H; McCulloch, Andrew D

2016-12-01

Congenital heart disease is associated with abnormal ventricular shape that can affect wall mechanics and may be predictive of long-term adverse outcomes. Atlas-based parametric shape analysis was used to analyze ventricular geometries of eight adolescent or adult single-ventricle CHD patients with tricuspid atresia and Fontans. These patients were compared with an "atlas" of non-congenital asymptomatic volunteers, resulting in a set of z-scores which quantify deviations from the control population distribution on a patient-by-patient basis. We examined the potential of these scores to: (1) quantify abnormalities of ventricular geometry in single ventricle physiologies relative to the normal population; (2) comprehensively quantify wall motion in CHD patients; and (3) identify possible relationships between ventricular shape and wall motion that may reflect underlying functional defects or remodeling in CHD patients. CHD ventricular geometries at end-diastole and end-systole were individually compared with statistical shape properties of an asymptomatic population from the Cardiac Atlas Project. Shape analysis-derived model properties, and myocardial wall motions between end-diastole and end-systole, were compared with physician observations of clinical functional parameters. Relationships between altered shape and altered function were evaluated via correlations between atlas-based shape and wall motion scores. Atlas-based shape analysis identified a diverse set of specific quantifiable abnormalities in ventricular geometry or myocardial wall motion in all subjects. Moreover, this initial cohort displayed significant relationships between specific shape abnormalities such as increased ventricular sphericity and functional defects in myocardial deformation, such as decreased long-axis wall motion. These findings suggest that atlas-based ventricular shape analysis may be a useful new tool in the management of patients with CHD who are at risk of impaired ventricular wall mechanics and chamber remodeling.

Timing of myocardial trpm7 deletion during cardiogenesis variably disrupts adult ventricular function, conduction, and repolarization.

PubMed

Sah, Rajan; Mesirca, Pietro; Mason, Xenos; Gibson, William; Bates-Withers, Christopher; Van den Boogert, Marjolein; Chaudhuri, Dipayan; Pu, William T; Mangoni, Matteo E; Clapham, David E

2013-07-09

Transient receptor potential (TRP) channels are a superfamily of broadly expressed ion channels with diverse physiological roles. TRPC1, TRPC3, and TRPC6 are believed to contribute to cardiac hypertrophy in mouse models. Human mutations in TRPM4 have been linked to progressive familial heart block. TRPM7 is a divalent-permeant channel and kinase of unknown function, recently implicated in the pathogenesis of atrial fibrillation; however, its function in ventricular myocardium remains unexplored. We generated multiple cardiac-targeted knockout mice to test the hypothesis that TRPM7 is required for normal ventricular function. Early cardiac Trpm7 deletion (before embryonic day 9; TnT/Isl1-Cre) results in congestive heart failure and death by embryonic day 11.5 as a result of hypoproliferation of the compact myocardium. Remarkably, Trpm7 deletion late in cardiogenesis (about embryonic day 13; αMHC-Cre) produces viable mice with normal adult ventricular size, function, and myocardial transcriptional profile. Trpm7 deletion at an intermediate time point results in 50% of mice developing cardiomyopathy associated with heart block, impaired repolarization, and ventricular arrhythmias. Microarray analysis reveals elevations in transcripts of hypertrophy/remodeling genes and reductions in genes important for suppressing hypertrophy (Hdac9) and for ventricular repolarization (Kcnd2) and conduction (Hcn4). These transcriptional changes are accompanied by action potential prolongation and reductions in transient outward current (Ito; Kcnd2). Similarly, the pacemaker current (If; Hcn4) is suppressed in atrioventricular nodal cells, accounting for the observed heart block. Trpm7 is dispensable in adult ventricular myocardium under basal conditions but is critical for myocardial proliferation during early cardiogenesis. Loss of Trpm7 at an intermediate developmental time point alters the myocardial transcriptional profile in adulthood, impairing ventricular function, conduction, and repolarization.

Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis.

PubMed

Patel, Keval; Griffing, George T; Hauptman, Paul J; Stolker, Joshua M

2016-04-01

Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy.

Assessment of Impact of Weight Loss on Left and Right Ventricular Functions and Value of Tissue Doppler Echocardiography in Obese Patients.

PubMed

Yuksel, Isa Oner; Akar Bayram, Nihal; Koklu, Erkan; Ureyen, Cagin Mustafa; Kucukseymen, Selcuk; Arslan, Sakir; Bozkurt, Engin

2016-06-01

In our study, we aimed to evaluate the effect of weight loss on left and right ventricular functions in obese patients. Thirty patients with a BMI greater than 30 kg/m(2) and without any exclusion criteria were included in the study. Left ventricular systolic and diastolic functions were assessed with conventional and tissue Doppler echocardiography (TDE). At the end of 3 months, echocardiographic examination was repeated in patients with weight loss for cardiac function evaluation and it was compared to the baseline echocardiographic parameters. At the end of 3 months of weight loss period, conventional Doppler echocardiography revealed an improvement in diastolic functions with an increase in mitral E-wave, a decrease in mitral A-wave and an increase in E/A ratio. Deceleration time and isovolumetric relaxation time were ascertained shortened and Tei index decreased. TDE showed an increase in left ventricular lateral wall systolic wave (Sm) and E-wave velocity (Em). Mitral septal annular isovolumetric acceleration time (IVA), Sm and Em, were found to be increased, whereas Tei index was ascertained reduced. Right ventricular tissue Doppler examination following weight loss revealed an increase in RV- IVA, RV-Sm, and RV-Em, and a decrease in Tei index. We disclosed that left ventricular structural changes and diastolic dysfunction occur in obese patients, and by weight loss, these abnormalities may be reversible which we demonstrated both by conventional and TDE. In addition, obesity might impair RV function as well, and we observed an enhancement in right ventricular functions by weight loss. © 2016, Wiley Periodicals, Inc.

Effect of canagliflozin on left ventricular diastolic function in patients with type 2 diabetes.

PubMed

Matsutani, Daisuke; Sakamoto, Masaya; Kayama, Yosuke; Takeda, Norihiko; Horiuchi, Ryuzo; Utsunomiya, Kazunori

2018-05-22

Type 2 diabetes mellitus (T2DM) greatly increases the risks of cardiovascular disease and heart failure. In particular, left ventricular diastolic dysfunction that develops from the early stages of T2DM is an important factor in the onset and exacerbation of heart failure. The effect of sodium-glucose cotransporter 2 inhibitors on left ventricular diastolic function has not been elucidated. We have performed the first prospective study on the effects of canagliflozin on left ventricular diastolic function in T2DM. This study was performed to evaluate the effects of additional treatment with canagliflozin for 3 months on left ventricular diastolic function in patients with T2DM. A total of 38 patients with T2DM were consecutively recruited for this study. Left ventricular diastolic function was assessed by echocardiography. The primary study outcome was a change in the septal E/e' as a parameter of left ventricular diastolic function. A total of 37 patients (25 males and 12 females) were included in the analysis. Mean age of participants was 64.2 ± 8.1 years (mean ± SD), mean duration of diabetes was 13.5 ± 8.1 years, and mean HbA1c was 7.9 ± 0.7%. Of the participants, 86.5% had hypertension, 100% had dyslipidemia, and 32.4% had cardiovascular disease. Canagliflozin significantly improved left ventricular diastolic function (septal E/e' ratio 13.7 ± 3.5-12.1 ± 2.8, p = 0.001). Furthermore, among the various parameters that changed through the administration of canagliflozin, only changes in hemoglobin significantly correlated with changes in the septal E/e' ratio (p = 0.002). In multiple regression analysis, changes in hemoglobin were also revealed to be an independent predictive factor for changes in the septal E/e' ratio. This study showed for the first time that canagliflozin could improve left ventricular diastolic function within 3 months in patients with T2DM. The benefit was especially apparent in patients with substantially improved hemoglobin values. Trial registration UMIN Clinical Trials Registry UMIN000028141.

Right ventricular function after repair of tetralogy of Fallot: a comparison between bovine pericardium and porcine small intestinal extracellular matrix.

PubMed

Naik, Ronak; Johnson, Jason; Kumar, T K S; Philip, Ranjit; Boston, Umar; Knott-Craig, Christopher J

2017-05-29

The porcine small intestinal extracellular matrix reportedly has the potential to differentiate into viable myocardial cells. When used in tetralogy of Fallot repair, it may improve right ventricular function. We evaluated right ventricular function after repair of tetralogy of Fallot with extracellular matrix versus bovine pericardium. Subjects with non-transannular repair of tetralogy of Fallot with at least 1 year of follow-up were selected. The extracellular matrix and bovine pericardium groups were compared. We used three-dimensional right ventricular ejection fraction, right ventricle global longitudinal strain, and tricuspid annular plane systolic excursion to assess right ventricular function. The extracellular matrix group had 11 patients, whereas the bovine pericardium group had 10 patients. No differences between the groups were found regarding sex ratio, age at surgery, and cardiopulmonary bypass time. The follow-up period was 28±12.6 months in the extracellular matrix group and 50.05±17.6 months in the bovine pericardium group (p=0.001). The mean three-dimensional right ventricular ejection fraction (55.7±5.0% versus 55.3±5.2%, p=0.73), right ventricular global longitudinal strain (-18.5±3.0% versus -18.0±2.2%, p=0.44), and tricuspid annular plane systolic excursions (1.59±0.16 versus 1.59±0.2, p=0.93) were similar in the extracellular matrix group and in the bovine pericardium group, respectively. Right ventricular global longitudinal strain in healthy children is reported at -29±3% in literature. In a small cohort of the patients undergoing non-transannular repair of tetralogy of Fallot, there was no significant difference in right ventricular function between groups having extracellular matrix versus bovine pericardium patches followed-up for more than 1 year. Lower right ventricular longitudinal strain noted in both the groups compared to healthy children.

Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog

PubMed Central

Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Kagawa, Yumiko; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

2017-01-01

A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls. PMID:29089652

Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog.

PubMed

Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Kagawa, Yumiko; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

2017-11-01

A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls.

Circular pump support of blood circulation in the human body

NASA Astrophysics Data System (ADS)

Medvedev, A. E.; Fomin, V. M.; Prikhodko, Yu. M.; Cherniavskiy, A. M.; Fomichev, V. P.; Fomichev, A. V.; Chekhov, V. P.; Ruzmatov, T. M.

2016-10-01

The need of circulatory support systems in the treatment of chronic heart failure is increasing constantly, as 20% of patients in the waiting list die every year. Despite the great need for mechanical heart support systems, using of available systems is limited by the expensiveness. In addition, there is no one system that is 100% responsible to all medical and technical requirements, and would be completely safe for patient. Therefore, further research in the field of circu-latory support systems, considering health and technical requirements is relevant. One of the new directions in the study are disc pumps of viscous friction for liquid transporting, based on the Tesla pump principle. The operation principle of pumps based on the phenomenon of the boundary layer which is formed on the disk rotating in a fluid. There are experimental studies results of models with different variants of the rotor suspension, the various forms and the number of disks, forms the pump housing. However, none of the above samples was not brought to clinical trials. Furthermore, despite the promise of this model is still used today in some circulatory support systems are no similar type pump. Published data provide a basis for further development and testing of the pump model and allow to hope for leveling a number of significant shortcomings of modern left ventricular bypass systems.

Prototype Continuous Flow Ventricular Assist Device Supported on Magnetic Bearings.

PubMed

Allaire, P E; Kim, H C; Maslen, E H; Olsen, D B; Bearnson, G B

1996-05-01

This article describes a prototype continuous flow pump (CFVAD2) fully supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. The pump delivered 6 L/min of flow at 100 mm Hg of differential pressure head operating at 2,400 rpm in water. The pump is totally supported in 4 magnetic bearings: 2 radial and 2 thrust. Magnetic bearings offer the advantages of no required lubrication and large operating clearances. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity and current gains are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water. Much lower levels of force were found than were expected, allowing for a very significant reduction in the size of the next prototype. Hemolysis levels were measured in the prototype pump and found not to indicate damage to the blood cells. © 1996 International Society for Artificial Organs.

CFD Design and Analysis of a Passively Suspended Tesla Pump Left Ventricular Assist Device

PubMed Central

Medvitz, Richard B.; Boger, David A.; Izraelev, Valentin; Rosenberg, Gerson; Paterson, Eric G.

2012-01-01

This paper summarizes the use of computational fluid dynamics (CFD) to design a novelly suspended Tesla LVAD. Several design variants were analyzed to study the parameters affecting device performance. CFD was performed at pump speeds of 6500, 6750 and 7000 RPM and at flow rates varying from 3 to 7 liter-per-minute (LPM). The CFD showed that shortening the plates nearest the pump inlet reduced the separations formed beneath the upper plate leading edges and provided a more uniform flow distribution through the rotor gaps, both of which positively affected the device hydrodynamic performance. The final pump design was found to produce a head rise of 77 mmHg with a hydraulic efficiency of 16% at the design conditions of 6 LPM throughflow and a 6750 RPM rotation rate. To assess the device hemodynamics the strain rate fields were evaluated. The wall shear stresses demonstrated that the pump wall shear stresses were likely adequate to inhibit thrombus deposition. Finally, an integrated field hemolysis model was applied to the CFD results to assess the effects of design variation and operating conditions on the device hemolytic performance. PMID:21595722

Cardiovascular magnetic resonance of cardiac function and myocardial mass in preterm infants: a preliminary study of the impact of patent ductus arteriosus

PubMed Central

2014-01-01

Background Many pathologies seen in the preterm population are associated with abnormal blood supply, yet robust evaluation of preterm cardiac function is scarce and consequently normative ranges in this population are limited. The aim of this study was to quantify and validate left ventricular dimension and function in preterm infants using cardiovascular magnetic resonance (CMR). An initial investigation of the impact of the common congenital defect patent ductus arteriosus (PDA) was then carried out. Methods Steady State Free Procession short axis stacks were acquired. Normative ranges of left ventricular end diastolic volume (EDV), stroke volume (SV), left ventricular output (LVO), ejection fraction (EF), left ventricular (LV) mass, wall thickness and fractional thickening were determined in “healthy” (control) neonates. Left ventricular parameters were then investigated in PDA infants. Unpaired student t-tests compared the 2 groups. Multiple linear regression analysis assessed impact of shunt volume in PDA infants, p-value ≤ 0.05 being significant. Results 29 control infants median (range) corrected gestational age at scan 34+6(31+1-39+3) weeks were scanned. EDV, SV, LVO, LV mass normalized by weight and EF were shown to decrease with increasing corrected gestational age (cGA) in controls. In 16 PDA infants (cGA 30+3(27+3-36+1) weeks) left ventricular dimension and output were significantly increased, yet there was no significant difference in ejection fraction and fractional thickening between the two groups. A significant association between shunt volume and increased left ventricular mass correcting for postnatal age and corrected gestational age existed. Conclusion CMR assessment of left ventricular function has been validated in neonates, providing more robust normative ranges of left ventricular dimension and function in this population. Initial investigation of PDA infants would suggest that function is relatively maintained. PMID:25160730

Design and Development of a Miniaturized Percutaneously Deployable Wireless Left Ventricular Assist Device: Early Prototypes and Feasibility Testing.

PubMed

Letzen, Brian; Park, Jiheum; Tuzun, Zeynep; Bonde, Pramod

The current left ventricular assist devices (LVADs) are limited by a highly invasive implantation procedure in a severely unstable group of advanced heart failure patients. Additionally, the current transcutaneous power drive line acts as a nidus for infection resulting in significant morbidity and mortality. In an effort to decrease this invasiveness and eliminate drive line complications, we have conceived a wireless miniaturized percutaneous LVAD, capable of being delivered endovascularly with a tether-free operation. The system obviates the need for a transcutaneous fluid purge line required in existing temporary devices by utilizing an incorporated magnetically coupled impeller for a complete seal. The objective of this article was to demonstrate early development and proof-of-concept feasibility testing to serve as the groundwork for future formalized device development. Five early prototypes were designed and constructed to iteratively minimize the pump size and improve fluid dynamic performance. Various magnetic coupling configurations were tested. Using SolidWorks and ANSYS software for modeling and simulation, several geometric parameters were varied. HQ curves were constructed from preliminary in vitro testing to characterize the pump performance. Bench top tests showed no-slip magnetic coupling of the impeller to the driveshaft up to the current limit of the motor. The pump power requirements were tested in vitro and were within the appropriate range for powering via a wireless energy transfer system. Our results demonstrate the proof-of-concept feasibility of a novel endovascular cardiac assist device with the potential to eventually offer patients an untethered, minimally invasive support.

A numerical method to enhance the performance of a cam-type electric motor-driven left ventricular assist device.

PubMed

Huang, Huan; Yang, Ming; Lu, Cunyue; Xu, Liang; Zhuang, Xiaoqi; Meng, Fan

2013-10-01

Pulsatile left ventricular assist devices (LVADs) driven by electric motors have been widely accepted as a treatment of heart failure. Performance enhancement with computer assistance for this kind of LVAD has seldom been reported. In this article, a numerical method is proposed to assist the design of a cam-type pump. The method requires an integrated model of an LVAD system, consisting of a motor, a transmission mechanism, and a cardiovascular circulation. Performance indices, that is, outlet pressure, outlet flow, and pump efficiency, were used to select the best cam profile from six candidates. A prototype pump connected to a mock circulatory loop (MCL) was used to calibrate the friction coefficient of the cam groove and preliminarily evaluate modeling accuracy. In vitro experiments show that the mean outlet pressure and flow can be predicted with high accuracy by the model, and gross geometries of the measurements can also be reproduced. Simulation results demonstrate that as the total peripheral resistance (TPR) is fixed at 1.1 mm Hg.s/mL, the two-cycle 2/3-rise profile is the best. Compared with other profiles, the maximum increases of pressure and flow indices are 75 and 76%, respectively, and the maximum efficiency increase is over 51%. For different TPRs (0.5∼1.5 mm Hg.s/mL) and operation intervals (0.1∼0.4 s) in counterpulsation, the conclusion is also acceptable. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Evaluation of training nurses to perform semi-automated three-dimensional left ventricular ejection fraction using a customised workstation-based training protocol.

PubMed

Guppy-Coles, Kristyan B; Prasad, Sandhir B; Smith, Kym C; Hillier, Samuel; Lo, Ada; Atherton, John J

2015-06-01

We aimed to determine the feasibility of training cardiac nurses to evaluate left ventricular function utilising a semi-automated, workstation-based protocol on three dimensional echocardiography images. Assessment of left ventricular function by nurses is an attractive concept. Recent developments in three dimensional echocardiography coupled with border detection assistance have reduced inter- and intra-observer variability and analysis time. This could allow abbreviated training of nurses to assess cardiac function. A comparative, diagnostic accuracy study evaluating left ventricular ejection fraction assessment utilising a semi-automated, workstation-based protocol performed by echocardiography-naïve nurses on previously acquired three dimensional echocardiography images. Nine cardiac nurses underwent two brief lectures about cardiac anatomy, physiology and three dimensional left ventricular ejection fraction assessment, before a hands-on demonstration in 20 cases. We then selected 50 cases from our three dimensional echocardiography library based on optimal image quality with a broad range of left ventricular ejection fractions, which was quantified by two experienced sonographers and the average used as the comparator for the nurses. Nurses independently measured three dimensional left ventricular ejection fraction using the Auto lvq package with semi-automated border detection. The left ventricular ejection fraction range was 25-72% (70% with a left ventricular ejection fraction <55%). All nurses showed excellent agreement with the sonographers. Minimal intra-observer variability was noted on both short-term (same day) and long-term (>2 weeks later) retest. It is feasible to train nurses to measure left ventricular ejection fraction utilising a semi-automated, workstation-based protocol on previously acquired three dimensional echocardiography images. Further study is needed to determine the feasibility of training nurses to acquire three dimensional echocardiography images on real-world patients to measure left ventricular ejection fraction. Nurse-performed evaluation of left ventricular function could facilitate the broader application of echocardiography to allow cost-effective screening and monitoring for left ventricular dysfunction in high-risk populations. © 2014 John Wiley & Sons Ltd.

New concept of the contraction-extension property of the left ventricular myocardium.

PubMed

Tanaka, Motonao; Sakamoto, Tsuguya; Sugawara, Shigeo; Katahira, Yoshiaki; Tabuchi, Haruna; Nakajima, Hiroyuki; Kurokawa, Takafumi; Kanai, Hiroshi; Hasegawa, Hideyuki; Ohtsuki, Shigeo

2014-04-01

Using newly developed ultrasonic technology, we attempted to disclose the characteristics of the left ventricular (LV) contraction-extension (C-E) property, which has an important relationship to LV function. Strain rate (SR) distribution within the posterior wall and interventricular septum was microscopically measured with a high accuracy of 821μm in spatial resolution by using the phase difference tracking method. The subjects were 10 healthy men (aged 30-50 years). The time course of the SR distribution disclosed the characteristic C-E property, i.e. the contraction started from the apex and propagated toward the base on one hand, and from the epicardial side toward the endocardial side on the other hand. Therefore, the contraction of one area and the extension of another area simultaneously appeared through nearly the whole cardiac cycle, with the contracting part positively extending the latter part and vice versa. The time course of these propagations gave rise to the peristalsis and the bellows action of the LV wall, and both contributed to effective LV function. The LV contraction started coinciding in time with the P wave of the electrocardiogram, and the cardiac cycle was composed of 4 phases, including 2 types of transitional phase, as well as the ejection phase and slow filling phase. The sum of the measurement time duration of either the contraction or the extension process occupied nearly equal duration in normal conditions. The newly developed ultrasonic technology revealed that the SR distribution was important in evaluating the C-E property of the LV myocardium. The harmonious succession of the 4 cardiac phases newly identified seemed to be helpful in understanding the mechanism to keep long-lasting pump function of the LV. Copyright © 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Impeller behavior and displacement of the VentrAssist implantable rotary blood pump.

PubMed

Chung, Michael K H; Zhang, Nong; Tansley, Geoff D; Woodard, John C

2004-03-01

The VentrAssist implantable rotary blood pump, intended for long-term ventricular assist, is under development and is currently being tested for its rotor-dynamic stability. The pump is of the centrifugal type and consists of a shaftless impeller, also acting as the rotor of the brushless DC motor. The impeller remains passively suspended in the pump cavity by hydrodynamic forces, resulting from the small clearances between the impeller outside surfaces and the pump cavity. In the older version of the pump tested, these small clearances range from approximately 50 microm to 230 microm; the displacement of the impeller relative to the pump cavity is unknown in use. This article presents two experiments: the first measured displacement of the impeller using eddy-current proximity sensors and laser proximity sensors. The second experiment used Hall-effect proximity sensors to measure the displacement of the impeller relative to the pump cavity. All transducers were calibrated prior to commencement of the experiments. Voltage output from the transducers was converted into impeller movement in five degrees of freedom (x, y, z, theta(x), and theta(y)). The sixth degree of freedom, the rotation about the impeller axis (theta(z)), was determined by the commutation performed by the motor controller. The impeller displacement was found to be within the acceptable range of 8 micro m to 222 microm, avoiding blood damage and contact between the impeller and cavity walls. Thus the impeller was hydrodynamically suspended within the pump cavity and results were typical of centrifugal pump behavior. This research will be the basis for further investigation into the stiffness and damping coefficient of the pump's hydrodynamic bearing.

Kawasaki syndrome in an adult: endomyocardial histology and ventricular function during acute and recovery phases of illness.

PubMed

Marcella, J J; Ursell, P C; Goldberger, M; Lovejoy, W; Fenoglio, J J; Weiss, M B

1983-08-01

Kawasaki syndrome, an acute systemic inflammatory illness of unknown origin usually affecting children, may develop into a serious illness complicated by coronary artery aneurysms or myocarditis. This report describes an adult with Kawasaki syndrome studied by right ventricular endomyocardial biopsy and cardiac catheterization during the acute and recovery phases of illness. The initial biopsy specimen showed acute myocarditis and was associated with hemodynamic evidence of biventricular dysfunction, a severely depressed left ventricular ejection fraction and global hypokinesia. With time, there was spontaneous and rapid resolution of the inflammatory cell infiltrate with concurrent return to normal myocardial function. Right ventricular endomyocardial biopsy studies early in the course of the cardiac disease associated with Kawasaki syndrome may correlate with ventricular function and may be useful for monitoring immunosuppressive therapy in patients with this syndrome.

Evaluation of a new 3-dimensional color Doppler flow method to quantify flow across the mitral valve and in the left ventricular outflow tract: an in vitro study.

PubMed

Kimura, Sumito; Streiff, Cole; Zhu, Meihua; Shimada, Eriko; Datta, Saurabh; Ashraf, Muhammad; Sahn, David J

2014-02-01

The aim of this study was to assess the accuracy, feasibility, and reproducibility of determining stroke volume from a novel 3-dimensional (3D) color Doppler flow quantification method for mitral valve (MV) inflow and left ventricular outflow tract (LVOT) outflow at different stroke volumes when compared with the actual flow rate in a pumped porcine cardiac model. Thirteen freshly harvested pig hearts were studied in a water tank. We inserted a latex balloon into each left ventricle from the MV annulus to the LVOT, which were passively pumped at different stroke volumes (30-80 mL) using a calibrated piston pump at increments of 10 mL. Four-dimensional flow volumes were obtained without electrocardiographic gating. The digital imaging data were analyzed offline using prototype software. Two hemispheric flow-sampling planes for color Doppler velocity measurements were placed at the MV annulus and LVOT. The software computed the flow volumes at the MV annulus and LVOT within the user-defined volume and cardiac cycle. This novel 3D Doppler flow quantification method detected incremental increases in MV inflow and LVOT outflow in close agreement with pumped stroke volumes (MV inflow, r = 0.96; LVOT outflow, r = 0.96; P < .01). Bland-Altman analysis demonstrated overestimation of both (MV inflow, 5.42 mL; LVOT outflow, 4.46 mL) with 95% of points within 95% limits of agreement. Interobserver variability values showed good agreement for all stroke volumes at both the MV annulus and LVOT. This study has shown that the 3D color Doppler flow quantification method we used is able to compute stroke volumes accurately at the MV annulus and LVOT in the same cardiac cycle without electrocardiographic gating. This method may be valuable for assessment of cardiac output in clinical studies.

Hemodynamic Performance of a Novel Right Ventricular Assist Device (PERKAT).

PubMed

Kretzschmar, Daniel; Schulze, P Christian; Ferrari, Markus W

Acute right ventricular failure (RVF) is an increasing clinical problem and a life-threatening condition. Right ventricular assist devices represent a reasonable treatment option for patients with refractory RVF. We here present a novel percutaneously implantable device for right ventricular support. The PERKAT device is based on a nitinol stent cage, which is covered with valve-carrying foils. A flexible outlet trunk with a pigtail tip is connected to the distal part. The device is driven by an intra-aortic balloon pump (IABP) drive unit, which inflates/deflates a standard IABP-balloon placed within the stent cage. In-vitro evaluation was done in a liquid bath containing water or blood analog. The PERKAT device was tested in different afterload settings using two different IABP-balloons and varying inflation/deflation rates. We detected flow rates ranging from 1.97 to 3.93 L/min depending on the afterload setting, inflation/deflation rate, balloon size, and the medium used. Flow rates between water and blood analog were nearly comparable, and in the higher inflation/deflation rate settings slightly higher with water. Based on this promising in vitro data, the innovative percutaneously implantable PERKAT device has a potential to become a therapeutic option for patients with RVF refractory to medical treatment.

Clinical and hemodynamic effects of intra-aortic balloon pump therapy in chronic heart failure patients with cardiogenic shock.

PubMed

Fried, Justin A; Nair, Abhinav; Takeda, Koji; Clerkin, Kevin; Topkara, Veli K; Masoumi, Amirali; Yuzefpolskaya, Melana; Takayama, Hiroo; Naka, Yoshifumi; Burkhoff, Daniel; Kirtane, Ajay; Dimitrios Karmpaliotis, S M; Moses, Jeffrey; Colombo, Paolo C; Garan, A Reshad

2018-03-20

The role of the intra-aortic balloon pump (IABP) in acute decompensated heart failure (HF) with cardiogenic shock (CS) is largely undefined. In this study we sought to assess the hemodynamic and clinical response to IABP in chronic HF patients with CS and identify predictors of response to this device. We retrospectively reviewed all patients undergoing IABP implantation from 2011 to 2016 at our institution to identify chronic HF patients with acute decompensation and CS (cardiac index <2.2 liters/min/m 2 and systolic blood pressure <90 mm Hg or need for vasoactive medications to maintain this level). Clinical deterioration on IABP was defined as failure to bridge to either discharge on medical therapy or durable heart replacement therapy (HRT; durable left ventricular assist device or heart transplant) with IABP alone. We identified 132 chronic HF patients with IABP placed after decompensation with hemodynamic evidence of CS. Overall 30-day survival was 84.1%, and 78.0% of patients were successfully bridged to HRT or discharge without need for escalation of device support. The complication rate during IABP support was 2.3%. Multivariable analysis identified ischemic cardiomyopathy (odds ratio [OR] 3.24, 95% confidence interval [CI] 1.16 to 9.06; p = 0.03) and pulmonary artery pulsatility index (PAPi) <2.0 (OR 5.04, 95% CI 1.86 to 13.63; p = 0.001) as predictors of clinical deterioration on IABP. Overall outcomes with IABP in acute decompensated chronic HF patients are encouraging, and IABP is a reasonable first-line device for chronic HF patients with CS. Baseline right ventricular function, as measured by PAPi, is a major predictor of outcomes with IABP in this population. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

A multi-institutional outcome analysis of patients undergoing left ventricular assist device implantation stratified by sex and race.

PubMed

Meeteren, Justin van; Maltais, Simon; Dunlay, Shannon M; Haglund, Nicholas A; Beth Davis, Mary; Cowger, Jennifer; Shah, Palak; Aaronson, Keith D; Pagani, Francis D; Stulak, John M

2017-01-01

Earlier studies have demonstrated disparities in patients undergoing left ventricular assist device (LVAD) implantation when stratified according to sex and race. Because very few data exist from large investigations, we reviewed data from the registry of the Mechanical Circulatory Support Research Network. Between May 2004 and September 2014, 734 patients underwent primary LVAD implantation at our institutions. Median age at implant was 57 (range 18 to 82) years and there were 577 males (80%). Race included Caucasian (C) in 586 patients (82%), African-American (AA) in 112 (16%), and other (O) in 21 (3%). Between sexes, significant pre-operative differences most commonly included median age at implant (males 60 years, females 57 years), ischemic etiology (53% vs 35%) and mean INTERMACS profile (2.9 vs 2.5). Between races, significant pre-operative differences most commonly included median age at implant (C = 61 vs AA = 51 vs O = 51), New York Heart Association functional class (85% vs 100% vs 92%) and ischemic etiology (55% vs 24% vs 40%). There were no significant differences in survival at 1, 3 or 5 years by sex or race. Similarly, there were no differences in time-related freedom from stroke, drive-line infection, gastrointestinal bleeding or pump thrombus by sex or race. After controlling for differences, neither sex nor race was associated with survival (p = 0.09 and p = 0.18, respectively), stroke (p = 0.28 and p = 0.21), drive-line infection (p = 0.9 and p = 0.92), gastrointestinal bleed (p = 0.48 and p = 0.45) or pump thrombus (p = 0.99 and p = 0.8). In this large, multi-institutional analysis, although some pre-operative clinical characteristics varied, they did not translate into any significant differences in late survival or complications while on LVAD support. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

A cloud-based home management system for patients with a left ventricular assist device: a case report.

PubMed

Nomoto, Shinichi; Utsumi, Momoe; Minakata, Kenji

2016-07-04

Since implantable left ventricular assist devices (LVAD) with smaller configurations became available for bridge-to-transplant or even destination therapy in patients with end-stage heart failure, an increasing number of patients with these devices are receiving home medical management. However, these patients may be anxious about potential complications such as pump failure, thromboembolism, and infections that may occur during home management. To provide a sense of security during home management of patients with LVAD and to establish an ideal shared-care system, we developed a patient-centered cloud-based home management system for patients with LVAD. In this case report, we describe this system and report a trial of it in a 64-year-old patient with an LVAD.

No patch technique for complete atrioventricular canal repair.

PubMed

Aramendi, José Ignacio; Rodriguez, Miguel Angel; Luis, Teresa; Voces, Roberto

2006-08-01

We describe our initial experience with a new technique, consisting in direct closure of the ventricular septal defect component of the AV canal, by directly attaching the common bridging leaflets to the crest of the ventricular septum with interrupted sutures. After closure of the cleft, the ostium primum defect was closed with a running suture suturing the border of the septum primum to the newly created AV valve annulus. Three patients were operated upon. There was no mortality. Mean ischemic time was 39 min and mean pump time 77 min. All patients remained in sinus rhythm. At follow-up only trivial or mild mitral regurgitation was observed. This new technique permits the repair of complete AV canal without the need for any patch. It is fast, simple and reproducible.

iPhone in the Management of the Berlin Heart EXCOR Ventricular Assist Device.

PubMed

Badheka, Aditya; Allareddy, Veerajalandhar

Berlin Heart Inc. EXCOR is an extracorporeal pneumatically pulsatile ventricular assist device approved for use in pediatric age group since 2011 in the United States. It is a well-established life-saving therapy for the bridge to heart transplant or to provide circulatory support in a transplanted patient. The most commonly reported problem was "membrane defect" in a postmarketing major device reporting. In general, the filling and emptying of the pump can be easily visualized, but the interobserver variability exist. In this first novel report, we used the iPhone slow motion video to quantify and compare the differences in filling and emptying that positively impacted the management of the Berlin Heart. This is an initial exploratory concept that will need further studies to validate this bedside tool.

Experimental determination of dynamic characteristics of the VentrAssist implantable rotary blood pump.

PubMed

Chung, Michael K H; Zhang, Nong; Tansley, Geoff D; Qian, Yi

2004-12-01

The VentrAssist implantable rotary blood pump, intended for long-term ventricular assist, is under development and is currently being tested for its rotor-dynamic stability. The pump consists of a shaftless impeller, which also acts as the rotor of the brushless DC motor. The impeller remains passively suspended in the pump cavity by hydrodynamic forces, which result from the small clearances between the outside surfaces of the impeller and the pump cavity. These small clearances range from approximately 50 microm to 230 microm in size in the version of pump reported here. This article presents experimental investigation into the dynamic characteristics of the impeller-bearing-pump housing system of the rotary blood pump for increasing pump speeds at different flow rates. The pump was mounted on a suspension system consisting of a platform and springs, where the natural frequency and damping ratio for the suspension system were determined. Real-time measurements of the impeller's displacement were performed using Hall effect sensors. A vertical disturbance force was exerted onto the pump housing, causing the impeller to be displaced in vertical direction from its dynamic equilibrium position within the pump cavity. The impeller displacement was represented by a decaying sine wave, which indicated the impeller restoring to its equilibrium position. From the decaying sine wave the natural frequency and stiffness coefficient of the system were determined. Furthermore, the logarithmic decrement method was used to determine the damping ratio and eventually the damping coefficient of the system. Results indicate that stiffness and damping coefficients increased as flow rate and pump speed increased, representing an increase in stability with these changing conditions. However, pump speed had a greater influence on the stiffness and damping coefficients than flow rate did, which was evident through dynamic analysis. Overall the experimental method presented in this article was successful in determining the dynamic characteristics of the system.

Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

PubMed Central

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J.; Rasmussen, Helge H.

2016-01-01

The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no known physical barriers that account for such restricted Na+ diffusion, and we examined if changes of activity of the Na+-K+ pump itself cause the transient peak current. Reexposure to K+ reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na+ concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K+-free pipette solution could not be reconciled with restricted subsarcolemmal Na+ diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na+- and K+ concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na+-K+ pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na+-K+ pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K+-induced peak Na+-K+ pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K+-induced peak Na+-K+ pump current reflects the effect of conformation-dependent β1 pump subunit glutathionylation, not restricted subsarcolemmal diffusion of Na+. PMID:26958887

Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

PubMed

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

2016-03-08

The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect of conformation-dependent β1 pump subunit glutathionylation, not restricted subsarcolemmal diffusion of Na(+). Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Three-dimensional Echocardiography of Right Ventricular Function Correlates with Severity of Pediatric Pulmonary Hypertension.

PubMed

Jone, Pei-Ni; Patel, Sonali S; Cassidy, Courtney; Ivy, David Dunbar

2016-12-01

Right ventricular function and biomarkers of B-type natriuretic peptide (BNP) and N-Terminal pro-BNP (NT pro-BNP) are used to determine the severity of right ventricular failure and outcomes from pulmonary hypertension. Real-time three-dimensional echocardiography (3DE) is a novel quantitative measure of the right ventricle and decreases the geometric assumptions from conventional two-dimensional echocardiography (2DE). We correlated right ventricular functional measures using 2DE and single-beat 3DE with biomarkers and hemodynamics to determine the severity of pediatric pulmonary hypertension. We retrospectively evaluated 35 patients (mean age 12.67 ± 5.78 years) with established pulmonary hypertension who had echocardiograms and biomarkers on the same day. Ten out of 35 patients had hemodynamic evaluation within 3 days. 2DE evaluation included tricuspid annular plane systolic excursion (TAPSE), right ventricular myocardial performance index from tissue Doppler imaging (RV TDI MPI), and right ventricular fractional area change (FAC). Three-dimensional echocardiography evaluation included right ventricular ejection fraction (EF), end-systolic volume, and end-diastolic volume. The quality of the 3DE was graded as good, fair, or poor. Pearson correlation coefficients were utilized to evaluate between biomarkers and echocardiographic parameters and between hemodynamics and echocardiography. Three-dimensional echocardiography and FAC correlated significantly with BNP and NT pro-BNP. TAPSE and RV TDI MPI did not correlate significantly with biomarkers. 3D right ventricular EF correlated significantly with hemodynamics. Two-dimensional echocardiography did not correlate with hemodynamics. Single-beat 3DE is a noninvasive, feasible tool in the quantification of right ventricular function and maybe more accurate than conventional 2DE in evaluating severity of pulmonary hypertension. © 2016 Wiley Periodicals, Inc.

Hemodynamic and metabolic effects of para- versus intraaortic counterpulsatile circulation supports.

PubMed

Lu, Pong-Jeu; Lin, Pao-Yen; Yang, Chi-Fu Jeffrey; Hung, Chun-Hao; Chan, Ming-Yao; Hsu, Tzu-Cheng

2011-01-01

Despite the success of intraaortic balloon counterpulsation, data on physiologic indices and optimal inflation/deflation timing control of chronic counterpulsation devices are unclear. This study explored the acute hemodynamic and metabolic efficacy of a novel 40-ml stroke volume paraaortic blood pump (PABP) versus a standard intraaortic balloon pump (IABP). Acute porcine model was used with eight pigs randomly divided into PABP (n = 4) and IABP (n = 4) groups. Hemodynamic and metabolic measurements were obtained with and without mechanical assistance. In one pig, the inflation/deflation control was adjusted to different settings, with corresponding performance indices measured. The PABP significantly improved classical counterpulsation indices (p ≤ 0.05) and achieved an average beneficial effect on these indices 1.5-3.5 times greater than that of the IABP. Classical metabolic indices (tension time index and endocardial viability ratio [EVR]), and indices new to chronic counterpulsation research (coronary perfusion, left ventricular stroke work (SW), and a newly derived EVR) were also used in assessment. Both IABP assistance and PABP assistance improved these physiologic indices, with a trend toward PABP superiority in reducing left ventricular SW (p = 0.08). An optimal PABP deflation timing occurs during systole (25 milliseconds after the R-wave) and can minimize coronary regurgitation.

Cora rotary pump for implantable left ventricular assist device: biomaterial aspects.

PubMed

Montiès, J R; Dion, I; Havlik, P; Rouais, F; Trinkl, J; Baquey, C

1997-07-01

Our group is developing a left ventricular assist device based on the principle of the Maillard-Wankel rotative compressor: it is a rotary, not centrifugal, pump that produces a pulsatile flow. Stringent requirements have been defined for construction materials. They must be light, yet sufficiently hard and rigid, and able to be machined with high precision. The friction coefficient must be low and the wear resistance high. The materials must be chemically inert and not deformable. Also, the materials must be biocompatible, and the blood contacting surface must be hemocompatible. We assessed the materials in terms of physiochemistry, mechanics, and tribology to select the best for hemocompatibility (determined by studies of protein adsorption; platelet, leukocyte, and red cell retention; and hemolysis, among other measurements) and biocompatibility (determined by measurement of complement activation and toxicity, among other criteria). Of the materials tested, for short- and middle-term assistance, we chose titanium alloy (Ti6Al4V) and alumina ceramic (Al2O3) and for long-term and permanent use, composite materials (TiN coating on graphite). We saw that the polishing process of the substrate must be improved. For the future, the best coating material would be diamond-like carbon (DLC) or crystalline diamond coating.

B-type natriuretic peptide levels and continuous-flow left ventricular assist devices.

PubMed

Sareyyupoglu, Basar; Boilson, Barry A; Durham, Lucian A; McGregor, Christopher G A; Daly, Richard C; Redfield, Margaret M; Edwards, Brooks S; Frantz, Robert P; Pereira, Naveen L; Park, Soon J

2010-01-01

We postulated that postoperative B-type natriuretic peptide (BNP) levels would be reflective of the degree of hemodynamic support rendered by various pump speeds settings (RPM) of continuous-flow left ventricular assist devices (LVADs). Twenty LVAD patients were evaluated prospectively (Jarvik 2000: n = 9, HeartMate II: n = 11). The mean age was 57.7 ± 14.9 years, and 14 were male. B-type natriuretic peptide levels were drawn while the patients were supported on LVADs at variable RPM settings. The RPM settings were correlated with the changes in BNP levels. Eleven patients underwent LVAD implantation for a lifelong support while the rest were as a bridge therapy to transplantation. Four patients required LVAD change out for various causes of pump failure. Postoperative BNP levels decreased dramatically with the initiation of LVAD support. The levels correlated inversely with the degree of hemodynamic support rendered at various RPM settings of the HeartMate II (p < 0.001). Overall, BNP levels decreased significantly in 2 days after RPM increase. We observed a significant inverse correlation between the postoperative BNP levels and the degree of LVAD support. The effective LVAD support seems to result in a marked reduction in BNP levels, and monitoring serial BNP levels may be helpful in managing patients supported on continuous LVAD.

Modified fabrication techniques lead to improved centrifugal blood pump performance.

PubMed

Pacella, J J; Goldstein, A H; Magovern, G J; Clark, R F

1994-01-01

The authors are developing an implantable centrifugal blood pump for short- and medium-term (1-6 months) left ventricular assist. They hypothesized that the application of result dependent modifications to this pump would lead to overall improved performance in long-term implantation studies. Essential requirements for pump operation, such as durability and resistance to clot formation, have been achieved through specialized fabrication techniques. The antithrombogenic character of the pump has been improved through coating at the cannula-housing interfaces and the baffle seal, and through changing the impeller blade material from polysulfone to pyrolytic carbon. The electronic components of the pump have been sealed for implantable use through specialized processes of dipping and potting, and the surfaces of the internal pump components have been treated to increase durability. The device has demonstrated efficacy in five chronic sheep implantation studies of 14, 10, 28, 35, and 154 day duration. Post mortem findings from the 14 day experiment showed stable fibrin entangled around the impeller shaft and blades. After pump modification, autopsy findings of the 10 day study showed no evidence of clot. Additionally, the results of the 28 day experiment showed only a small (2.0 mm) ring of fibrin at the shaft-seal interface. In the 35 and 154 day experiments, redesign of the stators have resulted in improved motor corrosion resistance. The 35 day study showed a small, 0.5 mm wide fibrin deposit at the lip seal, but no motor failure. In the 154 day experiment, the motor failed because of stator fluid corrosion, while the explanted pump was devoid of thrombus. Based on these findings, the authors believe that these pump refinements have contributed significantly to improvements in durability and resistance to clot formation.

Permanent magnetic-levitation of rotating impeller: a decisive breakthrough in the centrifugal pump.

PubMed

Qian, K X; Zeng, P; Ru, W M; Yuan, H Y; Feng, Z G; Li, L

2002-01-01

Magnetic bearings have no mechanical contact between the rotor and stator, and a rotary pump with magnetic bearings therefore has no mechanical wear and thrombosis. The magnetic bearings available, however, contain electromagnets, are complicated to control and have high energy consumption. Therefore, it is difficult to apply an electromagnetic bearing to a rotary pump without disturbing its simplicity, reliability and ability to be implanted. The authors have developed a levitated impeller pump using only permanent magnets. The rotor is supported by permanent radial magnetic forces. The impeller is fixed on one side of the rotor; on the other side the rotor magnets are mounted. Opposite these rotor magents, a driving magnet is fastened to the motor axis. Thereafter, the motor drives the rotor via magnetic coupling. In laboratory tests with saline, where the rotor is still or rotates at under 4,000 rpm, the rotor magnets have one point in contact axially with a spacer between the rotor magnets and the driving magnets. The contacting point is located in the center of the rotor. As the rotating speed increases gradually to more than 4000 rpm, the rotor will disaffiliate from the stator axially, and become fully levitated. Since the axial levitation is produced by hydraulic force and the rotor magnets have a giro-effect, the rotor rotates very stably during levitation. As a left ventricular assist device, the pump works in a rotating speed range of 5,000-8,000 rpm, and the levitation of the impeller is assured by use of the pump. The permanent maglev impeller pump retains the advantages of the rotary pump but overcomes the disadvantages of the leviated pump with electromagnetic-bearing, and has met with most requirements of artificial heart blood pumps, thus promising to have more applications than previously.

An Echocardiographic Study of Left Ventricular Size and Cardiac Function in Adolescent Females with Anorexia Nervosa.

PubMed

Escudero, Carolina A; Potts, James E; Lam, Pei-Yoong; De Souza, Astrid M; Mugford, Gerald J; Sandor, George G S

2016-01-01

This retrospective case-control study investigated cardiac dimensions and ventricular function in female adolescents with anorexia nervosa (AN) compared with controls. Echocardiographic measurements of left ventricular (LV) dimensions, LV mass index, left atrial size and cardiac index were made. Detailed measures of systolic and diastolic ventricular function were made including tissue Doppler imaging. Patients were stratified by body mass index ≤10th percentile (AN ≤ 10th) and >10th percentile (AN > 10th). Ninety-five AN patients and 58 controls were included. AN and AN ≤ 10th groups had reduced LV dimensions, LV mass index, left atrial size and cardiac index compared with controls. There were no differences between groups in measures of systolic function. Measures of diastolic tissue Doppler imaging were decreased in AN and AN ≤ 10th. No differences in echocardiographic measurements existed between controls and AN > 10th. Female adolescents with AN have preserved systolic function and abnormalities of diastolic ventricular function. AN ≤ 10th may be a higher risk group. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Left ventricular functions in children with newly diagnosed Graves' disease. A single-center study from Upper Egypt.

PubMed

Metwalley, Kotb Abbass; Farghaly, Hekma Saad; Abdelhamid, Abdelrahman

2018-01-01

This study aimed to evaluate the left ventricular (LV) functions in a cohort of children with Graves' disease (GD). This is a cross-sectional case-control study. It included 36 children with GD and 36 healthy children matched for age and gender. Thyroid hormones (TSH, FT4, and FT3) and anti-thyroid autoantibodies [anti-thyroid peroxidase (anti-TPO), thyrotropin receptor (TRAbs), and thyroglobulin antibodies] were measured. Conventional and tissue Doppler imaging (TDI) echocardiographies were used to assess left ventricular systolic and diastolic functions. LV mass index (LVMI) and myocardial performance index (MPI) were also measured. Compared to healthy children, conventional echocardiography of patients with GD revealed higher LVMI (P = 0.001) indicating LV hypertrophy but normal LV functions while TDI revealed lower Em/Am ratio indicating LV diastolic dysfunction (P = 0.001). Significant correlations were reported between FT4 with LVMI (P = 0.05), Em/Am (P = 0.01), and MPI (P = 0.01). In multivariate analysis, a positive correlation was identified between FT4 with MPI (OR = 1.17; 95% CI = 1.09-1.15; P = 0.001). Children with newly diagnosed GD may have significant subclinical changes in LV structure and function (diastolic and global). TDI is more sensitive than conventional Doppler in detecting LV dysfunction. These findings highlight the importance of early monitoring of children with GD for left ventricular mass index and diastolic function. What is Known: • There is an increased risk for cardiac abnormalities in children with Graves' disease (GD). • Limited studies assessed left ventricular function in patients with GD. What is New: • Children with newly diagnosed GD may have significant subclinical changes in left ventricular structure and functions. • Children with newly diagnosed GD should be monitored for left ventricular mass index and diastolic function.

Assessment of right ventricular function with nonimaging first pass ventriculography and comparison of results with gamma camera studies.

PubMed

Zhang, Z; Liu, X J; Liu, Y Z; Lu, P; Crawley, J C; Lahiri, A

1990-08-01

A new technique has been developed for measuring right ventricular function by nonimaging first pass ventriculography. The right ventricular ejection fraction (RVEF) obtained by non-imaging first pass ventriculography was compared with that obtained by gamma camera first pass and equilibrium ventriculography. The data has demonstrated that the correlation of RVEFs obtained by the nonimaging nuclear cardiac probe and by gamma camera first pass ventriculography in 15 subjects was comparable (r = 0.93). There was also a good correlation between RVEFs obtained by the nonimaging nuclear probe and by equilibrium gated blood pool studies in 33 subjects (r = 0.89). RVEF was significantly reduced in 15 patients with right ventricular and/or inferior myocardial infarction compared to normal subjects (28 +/- 9% v. 45 +/- 9%). The data suggests that nonimaging probes may be used for assessing right ventricular function accurately.

The Ventricular Assist Device in the Life of the Child: A Phenomenological Pediatric Study.

PubMed

van Manen, Michael A

2017-05-01

What is it like for a child to live with an artificial heart? The use of some medical therapies in children requires developmental considerations, is associated with psychosocial consequences, and calls for ethical sensitivities. A critical case is the ventricular assist device (VAD), a mechanical pump used to support the functioning of a failing heart. As a pediatric therapy, the device can be used as a temporary solution for poor heart function, a bridge to transplantation or recovery, or as a destination therapy. While the mechanical-technical operation of the VAD is well understood, the clinical-technical aspects of young people living with this device are largely unexplored. Drawing on interviews of school-aged children, the aim of this phenomenological study is to explore how a VAD may structure or condition a child's meaningful experience of their world outside the hospital. The driveline of an implanted VAD is the peripheral attachment, extruding through the skin to connect the controller-power supply. The materiality of the device may be interruptive, restrictive, and disturbing to the psycho-physical being and sense of self-identity of the child as a child. And while a child equipped with a VAD is not necessarily conspicuous among other children, the child may experience the device as an exposing presence, while living with the worry of a caregiver who takes on the role not simply of parent but of watchful health professional. A phenomenological understanding of the VAD should assist parents and caregiving health professionals knowing how to deal with specific issues arising in the life of the VAD child.

Bleeding with the artificial heart: Gastrointestinal hemorrhage in CF-LVAD patients.

PubMed

Gurvits, Grigoriy E; Fradkov, Elena

2017-06-14

Continuous-flow left ventricular assist devices (CF-LVADs) have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or, more recently, as destination therapy. However, its implantations carries a risk of complications including infection, device malfunction, arrhythmias, right ventricular failure, thromboembolic disease, postoperative and nonsurgical bleeding. A significant number of left ventricular assist devices (LVAD) recipients may experience recurrent gastrointestinal hemorrhage, mainly due to combination of antiplatelet and vitamin K antagonist therapy, activation of fibrinolytic pathway, acquired von Willebrand factor deficiency, and tendency to develop small intestinal angiodysplasias due to increased rotary speed of the pump. Gastrointestinal bleeding in LVAD patients remains a source of increased morbidity including the need for blood transfusions, extended hospital stays, multiple readmissions, and overall mortality. Management of gastrointestinal bleeding in LVAD patients involves multidisciplinary approach in stabilizing the patients, addressing risk factors and performing structured endoluminal evaluation with focus on upper gastrointestinal tract including jejunum to find and eradicate culprit lesion. Medical and procedural intervention is largely successful and universal bleeding cessation occurs in transplanted patients.

Effect of intra-aortic balloon pump on coronary blood flow during different balloon cycles support: A computer study.

PubMed

Aye, Thin Pa Pa; Htet, Zwe Lin; Singhavilai, Thamvarit; Naiyanetr, Phornphop

2015-01-01

Intra-aortic balloon pump (IABP) has been used in clinical treatment as a mechanical circulatory support device for patients with heart failure. A computer model is used to study the effect on coronary blood flow (CBF) with different balloon cycles under both normal and pathological conditions. The model of cardiovascular and IABP is developed by using MATLAB SIMULINK. The effect on coronary blood flow has been studied under both normal and pathological conditions using different balloon cycles (balloon off; 1:4; 1:2; 1:1). A pathological heart is implemented by reducing the left ventricular contractility. The result of this study shows that the rate of balloon cycles is related to the level of coronary blood flow.

Increase in cardiac myosin heavy-chain (MyHC) alpha protein isoform in hibernating ground squirrels, with echocardiographic visualization of ventricular wall hypertrophy and prolonged contraction

PubMed Central

Nelson, O. Lynne; Rourke, Bryan C.

2013-01-01

SUMMARY Deep hibernators such as golden-mantled ground squirrels (Callospermophilus lateralis) have multiple challenges to cardiac function during low temperature torpor and subsequent arousals. As heart rates fall from over 300 beats min−1 to less than 10, chamber dilation and reduced cardiac output could lead to congestive myopathy. We performed echocardiography on a cohort of individuals prior to and after several months of hibernation. The left ventricular chamber exhibited eccentric and concentric hypertrophy during hibernation and thus calculated ventricular mass was ~30% greater. Ventricular ejection fraction was mildly reduced during hibernation but stroke volumes were greater due to the eccentric hypertrophy and dramatically increased diastolic filling volumes. Globally, the systolic phase in hibernation was ~9.5 times longer, and the diastolic phase was 28× longer. Left atrial ejection generally was not observed during hibernation. Atrial ejection returned weakly during early arousal. Strain echocardiography assessed the velocity and total movement distance of contraction and relaxation for regional ventricular segments in active and early arousal states. Myocardial systolic strain during early arousal was significantly greater than the active state, indicating greater total contractile movement. This mirrored the increased ventricular ejection fraction noted with early arousal. However, strain rates were slower during early arousal than during the active period, particularly systolic strain, which was 33% of active, compared with the rate of diastolic strain, which was 67% of active. As heart rate rose during the arousal period, myocardial velocities and strain rates also increased; this was matched closely by cardiac output. Curiously, though heart rates were only 26% of active heart rates during early arousal, the cardiac output was nearly 40% of the active state, suggesting an efficient pumping system. We further analyzed proportions of cardiac myosin heavy-chain (MyHC) isoforms in a separate cohort of squirrels over 5 months, including time points before hibernation, during hibernation and just prior to emergence. Hibernating individuals were maintained in both a 4°C cold room and a 20°C warm room. Measured by SDS-PAGE, relative percentages of cardiac MyHC alpha were increased during hibernation, at both hibernacula temperatures. A potential increase in contractile speed, and power, from more abundant MyHC alpha may aid force generation at low temperature and at low heart rates. Unlike many models of cardiomyopathies where the alpha isoform is replaced by the beta isoform in order to reduce oxygen consumption, ground squirrels demonstrate a potential cardioprotective mechanism to maintain cardiac output during torpor. PMID:24072796

Right ventricular function during acute exacerbation of severe equine asthma.

PubMed

Decloedt, A; Borowicz, H; Slowikowska, M; Chiers, K; van Loon, G; Niedzwiedz, A

2017-09-01

Pulmonary hypertension has been described in horses with severe equine asthma, but its effect on the right ventricle has not been fully elucidated. To evaluate right ventricular structure and function after a 1-week period of pulmonary hypertension secondary to acute exacerbation of severe equine asthma. Prospective study. A clinical episode of severe equine asthma was induced experimentally in six susceptible horses. Examinations in remission and on day 7 of the clinical episode included a physical examination with clinical scoring, echocardiography, arterial blood gas measurements, venous blood sampling for cardiac biomarkers, intracardiac pressure measurements, right ventricular and right atrial myocardial biopsies, airway endoscopy and bronchoalveolar lavage. After 1 month of recovery, physical examination, echocardiography and cardiac biomarker analysis were repeated. Echocardiographic and pressure measurements were compared with those in 10 healthy control horses. All horses developed clinical signs of acute pulmonary obstruction. Right heart pressures increased significantly. Altered right ventricular function could be detected by tissue Doppler and speckle tracking echocardiography. Cardiac troponin concentrations did not increase significantly, but were highly elevated in one horse which exercised in the paddock prior to sampling. Focal neutrophil infiltration was present in two myocardial samples. Even in remission, asthmatic horses showed a thicker right ventricular wall, an increased left ventricular end-systolic eccentricity index at chordal level and decreased right ventricular longitudinal strain compared with controls. The induced clinical episode was rather mild and the number of horses was limited because of the invasive nature of the study. Pulmonary obstruction in asthmatic horses induces pulmonary hypertension with right ventricular structural and functional changes. © 2017 EVJ Ltd.

Fibrosis-Related Gene Expression in Single Ventricle Heart Disease.

PubMed

Nakano, Stephanie J; Siomos, Austine K; Garcia, Anastacia M; Nguyen, Hieu; SooHoo, Megan; Galambos, Csaba; Nunley, Karin; Stauffer, Brian L; Sucharov, Carmen C; Miyamoto, Shelley D

2017-12-01

To evaluate fibrosis and fibrosis-related gene expression in the myocardium of pediatric subjects with single ventricle with right ventricular failure. Real-time quantitative polymerase chain reaction was performed on explanted right ventricular myocardium of pediatric subjects with single ventricle disease and controls with nonfailing heart disease. Subjects were divided into 3 groups: single ventricle failing (right ventricular failure before or after stage I palliation), single ventricle nonfailing (infants listed for primary transplantation with normal right ventricular function), and stage III (Fontan or right ventricular failure after stage III). To evaluate subjects of similar age and right ventricular volume loading, single ventricle disease with failure was compared with single ventricle without failure and stage III was compared with nonfailing right ventricular disease. Histologic fibrosis was assessed in all hearts. Mann-Whitney tests were performed to identify differences in gene expression. Collagen (Col1α, Col3) expression is decreased in single ventricle congenital heart disease with failure compared with nonfailing single ventricle congenital heart disease (P = .019 and P = .035, respectively), and is equivalent in stage III compared with nonfailing right ventricular heart disease. Tissue inhibitors of metalloproteinase (TIMP-1, TIMP-3, and TIMP-4) are downregulated in stage III compared with nonfailing right ventricular heart disease (P = .0047, P = .013 and P = .013, respectively). Matrix metalloproteinases (MMP-2, MMP-9) are similar between nonfailing single ventricular heart disease and failing single ventricular heart disease, and between stage III heart disease and nonfailing right ventricular heart disease. There is no difference in the prevalence of right ventricular fibrosis by histology in subjects with single ventricular failure heart disease with right ventricular failure (18%) compared with those with normal right ventricular function (38%). Fibrosis is not a primary contributor to right ventricular failure in infants and young children with single ventricular heart disease. Additional studies are required to understand whether antifibrotic therapies are beneficial in this population. Copyright © 2017 Elsevier Inc. All rights reserved.

Power of resting echocardiographic measurements to classify pulmonary hypertension patients according to European society of cardiology exercise testing risk stratification cut-offs.

PubMed

Rehman, Michaela B; Garcia, Rodrigue; Christiaens, Luc; Larrieu-Ardilouze, Elisa; Howard, Luke S; Nihoyannopoulos, Petros

2018-04-15

Right ventricular function is the major determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). The ESC risk assessment strategy for PAH is based on clinical status, exercise testing, NTproBNP, imaging and haemodynamics but does not include right ventricular function. Our aims were to test the power of resting echocardiographic measurements to classify PAH patients according to ESC exercise testing risk stratification cut-offs and to determine if the classification power of echocardiographic parameters varied in chronic thrombo-embolic pulmonary hypertension (CTEPH). We prospectively and consecutively recruited 46 PAH patients and 42 CTEPH patients referred for cardio-pulmonary exercise testing and comprehensive transthoracic echocardiography. Exercise testing parameters analyzed were peak oxygen consumption, percentage of predicted maximal oxygen consumption and the slope of ventilation against carbon dioxide production. Receiver operator characteristic curves were used to determine the optimal diagnostic cut-off values of echocardiographic parameters for classifying the patients in intermediate or high risk category according to exercise testing. Measurements of right ventricular systolic function were the best for classifying in PAH (area under the curve 0.815 to 0.935). Measurements of right ventricular pressure overload (0.810 to 0.909) were optimal for classifying according to exercise testing in CTEPH. Measurements of left ventricular function were of no use in either group. Measurements of right ventricular systolic function can classify according to exercise testing risk stratification cut-offs in PAH. However, this is not the case in CTEPH where pressure overload, rather than right ventricular function seems to be linked to exercise performance. Copyright © 2018 Elsevier B.V. All rights reserved.

Amiodarone and Catheter Ablation as Cardiac Resynchronization Therapy for Children with Dilated Cardiomyopathy and Wolff-Parkinson-White Syndrome

PubMed Central

Kim, Sung Hoon; Jeong, Soo In; Kang, I-Seok; Lee, Heung Jae

2013-01-01

Preexcitation by accessory pathways (APs) is known to cause dyssynchrony of the ventricle, related to ventricular dysfunction. Correction of ventricular dyssynchrony can improve heart failure in cases of dilated cardiomyopathy (DCMP) with preexcitation. Here, we report the first case of a child with DCMP and Wolff-Parkinson-White (WPW) syndrome treated with amiodarone and radiofrequency catheter ablation (RFCA) in Korea. A 7-year-old boy, who suffered from DCMP and WPW syndrome, showed improved left ventricular function and clinical functional class after treatment with amiodarone to eliminate preexcitation. QRS duration and left ventricular ejection fraction (LVEF) were inversely correlated with amiodarone dosage. After confirming the reduction of preexcitation effects in DCMP, successful RFCA of the right anterior AP resulted in LVEF improvement, along with the disappearance of preexcitation. Our findings suggest that ventricular dyssynchrony, caused by preexcitation in DCMP with WPW syndrome, can worsen ventricular function and amiodarone, as well as RFCA, which should be considered as a treatment option, even in young children. PMID:23407697

Control of a rotary pulsatile cardiac assist pump driven by an electric motor without a pressure sensor to avoid collapse of the pump inlet.

PubMed

Trinkl, J; Havlik, P; Mesana, T; Mitsui, N; Morita, S; Demunck, J L; Tourres, J L; Monties, J R

1993-01-01

Our ventricular assist device uses a valveless volumetric pump operating on the Maillard-Wankel rotary principle. It is driven by an electric motor and provides a semi pulsatile flow. At each cycle, blood is actively aspirated into the device, and overpumping results in collapse at the pump inlet. To prevent overpumping, it is necessary to ensure that pump intake does not exceed venous return. Poor long-term reliability rules out the use of current implantable pressure sensors for this purpose. To resolve this problem, we have developed a method of control based on monitoring of the intensity of electric current consumed by the motor. The method consists of real time monitoring of current intensity at the beginning of each pump cycle. A sudden change in intensity indicates underfilling, and motor speed is reduced to prevent collapse. The current consumed by the motor also depends on the afterload, but the form of the signal remains the same when afterload changes. After demonstrating the feasibility of this technique in a simulator, we are now testing it in animals. We were able to detect and prevent collapse due to overpumping by the cardiac assist device. This system also enables us to know the maximum possible assistance and to thus adapt assistance to the user.

Myosin filament activation in the heart is tuned to the mechanical task

PubMed Central

Reconditi, Massimo; Caremani, Marco; Pinzauti, Francesca; Powers, Joseph D.; Narayanan, Theyencheri; Stienen, Ger J. M.; Linari, Marco; Lombardi, Vincenzo

2017-01-01

The mammalian heart pumps blood through the vessels, maintaining the dynamic equilibrium in a circulatory system driven by two pumps in series. This vital function is based on the fine-tuning of cardiac performance by the Frank–Starling mechanism that relates the pressure exerted by the contracting ventricle (end systolic pressure) to its volume (end systolic volume). At the level of the sarcomere, the structural unit of the cardiac myocytes, the Frank–Starling mechanism consists of the increase in active force with the increase of sarcomere length (length-dependent activation). We combine sarcomere mechanics and micrometer–nanometer-scale X-ray diffraction from synchrotron light in intact ventricular trabeculae from the rat to measure the axial movement of the myosin motors during the diastole–systole cycle under sarcomere length control. We find that the number of myosin motors leaving the off, ATP hydrolysis-unavailable state characteristic of the diastole is adjusted to the sarcomere length-dependent systolic force. This mechanosensing-based regulation of the thick filament makes the energetic cost of the systole rapidly tuned to the mechanical task, revealing a prime aspect of the Frank–Starling mechanism. The regulation is putatively impaired by cardiomyopathy-causing mutations that affect the intramolecular and intermolecular interactions controlling the off state of the motors. PMID:28265101

First report of atretic coronary sinus stenting in a 5-kg infant resulting in dramatic improvement of ventricular function in functional single ventricle.

PubMed

El-Said, Howaida; Hegde, Sanjeet; Moore, John

2014-01-01

The patient was a male infant with L-transposition of great arteries (L-TGA), Ebstein's anomaly of the tricuspid valve, subvalvar aortic stenosis, ventricular septal defect (VSD), hypoplastic right ventricle, arch hypoplasia, and congenital complete heart block. He underwent a Norwood procedure, aortic arch repair, permanent pacemaker implantation, and a 3.5-mm aortopulmonary shunt at 4 days of age. At the time of his surgery, left ventricular function was in the normal range (ejection fraction [EF] = 67%). However by 3 months of age, he was noted to have developed moderate-severe biventricular dysfunction (left ventricular ejection fraction [LVEF] = 34%). Atresia of the coronary sinus with a small left superior venacava (LSVC) and a bridging vein was discovered during cardiac catheterization at this time. The coronary sinus mean pressure was 17 mm Hg, and the common atrial mean pressure was 6 mmHg. We opened the atretic coronary sinus ostium using radiofrequency ablation and stent placement. There was dramatic improvement in ventricular function observed over a 2-month period. Follow-up cardiac catheterization 5 months later revealed the stent in the coronary sinus to be widely patent with no intimal buildup, and the ventricular function was normal (LVEF = 58%). The patient had a bidirectional Glenn procedure with an uncomplicated postoperative course and is currently awaiting Fontan completion. © 2013 Wiley Periodicals, Inc.

The influence of type 2 diabetes and gender on ventricular repolarization dispersion in patients with sub-clinic left ventricular diastolic dysfunction

PubMed Central

Jani, Ylber; Kamberi, Ahmet; Xhunga, Sotir; Pocesta, Bekim; Ferati, Fatmir; Lala, Dali; Zeqiri, Agim; Rexhepi, Atila

2015-01-01

Objective: To assess the influence of type 2 DM and gender, on the QT dispersion, Tpeak-Tend dispersion of ventricular repolarization, in patients with sub-clinic left ventricular diastolic dysfunction of the heart. Background: QT dispersion, that reflects spatial inhomogeneity in ventricular repolarization, Tpeak-Tend dispersion, this on the other hand reflects transmural inhomogeneity in ventricular repolarization, that is increased in an early stage of cardiomyopathy, and in patients with left ventricular diastolic dysfunction, as well. The left ventricular diastolic dysfunction, a basic characteristic of diabetic heart disease (diabetic cardiomyopathy), that developes earlier than systolic dysfunction, suggests that diastolic markers might be sensitive for early cardiac injury. It is also demonstrated that gender has complex influence on indices of myocardial repolarization abnormalities such as QT interval and QT dispersion. Material and methods: We performed an observational study including 300 diabetic patients with similar epidemiological-demographic characteristics recruited in our institution from May 2009 to July 2014, divided into two groups. Demographic and laboratory echocardiographic data were obtained, twelve lead resting electrocardiography, QT, QTc, Tpeak-Tend-intervals and dispersion, were determined manually, and were compared between various groups. For statistical analysis a t-test, X2 test, and logistic regression are used according to the type of variables. A p value <0.05 was considered statistically significant for a confidence interval of 95%. Results: QTc max. interval, QTc dispersion and Tpeak-Tend dispersion, were significantly higher in diabetic group with subclinical LV (left ventricular) diastolic dysfunction, than in diabetic group with normal left ventricular diastolic function (445.24±14.7 ms vs. 433.55±14.4 ms, P<0.000; 44.98±18.78 ms vs. 32.05±17.9 ms, P<0.000; 32.60±1.6 ms vs. 17.46±2.0 ms, P<0.02. Prolonged QTc max. interval was found in 33% of patients, indiabetic group with subclinical left ventricular diastolic dysfunction vs. 13.3% of patients in diabetic group with normal left ventricular diastolic function, (Chi-square: 16.77, P<0.0001). A prolonged QTc dispersion, was found in 40.6% of patients, in diabetic group with subclinical left ventricular diastolic dysfunction vs. 20% of patients in diabetic group with normal left ventricular diastolic function Chi-square: 14.11, P<0.0002). A prolonged dispersion of Tpeak-Tend interval was found in 24% of patients in diabetic group with subclinical left ventricular diastolic dysfunction vs. 13.3% of patients in diabetic group with normal left ventricular diastolic function (Chi-square: 12.00, P<0.005). Females in diabetic group with subclinical left ventricular diastolic dysfunction in comparison with males in diabetic group with subclinical left ventricular diastolic dysfunction, have a significantly prolonged: mean QTc max. interval (23.3% vs. 10%, Chisquare: 12.0, P<0.005), mean QTc dispersion (27.3% vs. 13.3%, Chi-square: 10.24, P<0.001), mean Tpeak-Tend interval (10% vs. 3.3%, Chi-square: 5.77, P<0.01), mean Tpek-Tend dispersion (16.6% vs. 6.6%, Chi-square: 8.39, P<0.003). Conclusion: The present study has shown that influences of type 2 diabetes and gender in diabetics with sub-clinical left-ventricular diastolic dysfunction are reflected in a set of electrophysiological parameters that indicate a prolonged and more heterogeneous repolarization than in diabetic patients with normal diastolic function. In addition, it demonstrates that there exist differences between diabetic females with sub-clinic LV dysfunction and those with diabetes and normal LV function in the prevalence of increased set of electrophysiological parameters that indicate a prolonged and more heterogeneous repolarization. PMID:26550530

The influence of type 2 diabetes and gender on ventricular repolarization dispersion in patients with sub-clinic left ventricular diastolic dysfunction.

PubMed

Jani, Ylber; Kamberi, Ahmet; Xhunga, Sotir; Pocesta, Bekim; Ferati, Fatmir; Lala, Dali; Zeqiri, Agim; Rexhepi, Atila

2015-01-01

To assess the influence of type 2 DM and gender, on the QT dispersion, Tpeak-Tend dispersion of ventricular repolarization, in patients with sub-clinic left ventricular diastolic dysfunction of the heart. QT dispersion, that reflects spatial inhomogeneity in ventricular repolarization, Tpeak-Tend dispersion, this on the other hand reflects transmural inhomogeneity in ventricular repolarization, that is increased in an early stage of cardiomyopathy, and in patients with left ventricular diastolic dysfunction, as well. The left ventricular diastolic dysfunction, a basic characteristic of diabetic heart disease (diabetic cardiomyopathy), that developes earlier than systolic dysfunction, suggests that diastolic markers might be sensitive for early cardiac injury. It is also demonstrated that gender has complex influence on indices of myocardial repolarization abnormalities such as QT interval and QT dispersion. We performed an observational study including 300 diabetic patients with similar epidemiological-demographic characteristics recruited in our institution from May 2009 to July 2014, divided into two groups. Demographic and laboratory echocardiographic data were obtained, twelve lead resting electrocardiography, QT, QTc, Tpeak-Tend-intervals and dispersion, were determined manually, and were compared between various groups. For statistical analysis a t-test, X(2) test, and logistic regression are used according to the type of variables. A p value <0.05 was considered statistically significant for a confidence interval of 95%. QTc max. interval, QTc dispersion and Tpeak-Tend dispersion, were significantly higher in diabetic group with subclinical LV (left ventricular) diastolic dysfunction, than in diabetic group with normal left ventricular diastolic function (445.24±14.7 ms vs. 433.55±14.4 ms, P<0.000; 44.98±18.78 ms vs. 32.05±17.9 ms, P<0.000; 32.60±1.6 ms vs. 17.46±2.0 ms, P<0.02. Prolonged QTc max. interval was found in 33% of patients, indiabetic group with subclinical left ventricular diastolic dysfunction vs. 13.3% of patients in diabetic group with normal left ventricular diastolic function, (Chi-square: 16.77, P<0.0001). A prolonged QTc dispersion, was found in 40.6% of patients, in diabetic group with subclinical left ventricular diastolic dysfunction vs. 20% of patients in diabetic group with normal left ventricular diastolic function Chi-square: 14.11, P<0.0002). A prolonged dispersion of Tpeak-Tend interval was found in 24% of patients in diabetic group with subclinical left ventricular diastolic dysfunction vs. 13.3% of patients in diabetic group with normal left ventricular diastolic function (Chi-square: 12.00, P<0.005). Females in diabetic group with subclinical left ventricular diastolic dysfunction in comparison with males in diabetic group with subclinical left ventricular diastolic dysfunction, have a significantly prolonged: mean QTc max. interval (23.3% vs. 10%, Chisquare: 12.0, P<0.005), mean QTc dispersion (27.3% vs. 13.3%, Chi-square: 10.24, P<0.001), mean Tpeak-Tend interval (10% vs. 3.3%, Chi-square: 5.77, P<0.01), mean Tpek-Tend dispersion (16.6% vs. 6.6%, Chi-square: 8.39, P<0.003). The present study has shown that influences of type 2 diabetes and gender in diabetics with sub-clinical left-ventricular diastolic dysfunction are reflected in a set of electrophysiological parameters that indicate a prolonged and more heterogeneous repolarization than in diabetic patients with normal diastolic function. In addition, it demonstrates that there exist differences between diabetic females with sub-clinic LV dysfunction and those with diabetes and normal LV function in the prevalence of increased set of electrophysiological parameters that indicate a prolonged and more heterogeneous repolarization.

Importance of the mitral apparatus for left ventricular function: an experimental approach.

PubMed

Gams, E; Hagl, S; Schad, H; Heimisch, W; Mendler, N; Sebening, F

1992-01-01

In an experimental study of 31 anesthetized dogs the importance of the mitral apparatus for the left ventricular function was investigated. During extracorporeal circulation bileaflet mitral valve prostheses were implanted preserving the mitral subvalvular apparatus. Flexible wires were slung around the chordae tendineae and exteriorized through the left ventricular wall to cut the chordae by electrocautery from the outside when the heart was beating again. External and internal left ventricular dimensions were measured by sonomicrometry, left ventricular stroke volume by electromagnetic flowmeters around the ascending aorta, left ventricular end-diastolic volume by dye dilution technique, and left ventricular pressure by catheter tip manometers. Different preload levels were achieved by volume loading with blood transfusion before and after cutting the chordae tendineae. When the chordae had been divided peak systolic left ventricular pressure did not change. Heart rate only increased at the lowest left ventricular end-diastolic pressures of 3-4 mmHg, but remained unchanged at higher preload levels. Cardiac output decreased significantly up to -9% at left ventricular end-diastolic pressures of 5-10 mmHg, while left ventricular dp/dtmax showed a consistent reduction of up to -15% at any preload level. Significant reductions were also seen in systolic shortening in the left ventricular major axis (by external measurements -27%, by internal recording -43%). Left ventricular end-diastolic dimensions increased in the major axis by +2% when recorded externally, by +10% when measured internally. Systolic and diastolic changes in the minor axis were not consistent and different in the external and internal recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous internal counterpulsation as a bridge to recovery in acute and chronic heart failure

PubMed Central

Kontogiannis, Christos D; Malliaras, Konstantinos; Kapelios, Chris J; Mason, Jay W; Nanas, John N

2016-01-01

Cardiac recovery from cardiogenic shock (CS) and end-stage chronic heart failure (HF) remains an often insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic hemodynamics and left ventricular mechanoenergetics, rendering it attractive for promoting myocardial recovery in both acute and chronic HF. Although a recent clinical trial has questioned the clinical effectiveness of short-term hemodynamic support with intra-aortic balloon pump (IABP, the main representative of the counterpulsation technique) in CS complicating myocardial infarction, the issue remains open to further investigation. Moreover, preliminary data suggest that long-term IABP support in patients with end-stage HF is safe and may mediate recovery of left- or/and right-sided cardiac function, facilitating long-term weaning from mechanical support or enabling the application of other permanent, life-saving solutions. The potential of long-term counterpulsation could possibly be enhanced by implementation of novel, fully implantable counterpulsation devices. PMID:27011909

Intraoperative coronary grafts flow measurement using the TTFM flowmeter: results from a domestic sample.

PubMed

Succi, José Ernesto; Gerola, Luis Roberto; Succi, Guilherme de Menezes; Kim, Hyong Chun; Paredes, Jorge Edwin Morocho; Bufollo, Enio

2012-01-01

To evaluate intraoperative graft patency and identify grafts under risk of early occlusion. Fifty four patients were submitted to coronary artery bypass surgery and the graft flow was assessed by the Flowmeter (Medtronic Medistim), which utilizes the TTFM method. Three patients had left main disease and 48 had normal or mildly reduced left ventricular function. In hospital mortality was 3.7% (two patients), one for mesenteric thrombosis and one due to cardiogenic chock. Seventeen patients (34%) were submitted to off pump CABG. Arterial Graft flow measures ranged from 8 to 106 ml/min (average 31.14 ml/min), and venous grafts flow ranged from 9 to 149 ml/min (average 50.42 ml/min). Flowmeter use represents higher safety both for patients and surgeons. Even under legal aspects, the documentation provided by the device can avoid future questionings.

The successful implantation of continuous-flow left ventricular assist device as a destination therapy in Korea: echocardiographic assessment.

PubMed

Lee, Ga Yeon; Park, Sung-Ji; Kim, Sujin; Choi, Namgyung; Jeong, Dong Seop; Jeon, Eun-Seok; Lee, Young Tak

2014-01-01

Left ventricular assist device (LVAD) is a good treatment option for the patients ineligible for cardiac transplantation. Several studies have demonstrated that a ventricular assist device improves the quality of life and prognosis of the patients with end-stage heart failure. A 75-yr-old man debilitated with New York Heart Association (NYHA) functional class III-IV due to severe left ventricular systolic dysfunction received LVAD implantation as a destination therapy. The patient was discharged with improved functional status (NYHA functional class II) after appropriate cardiac rehabilitation and education about how to manage the device and potential emergency situations. This is the first case of successful continuous-flow LVAD implantation as a destination therapy in Korea.

Relationship between right and left ventricular function in candidates for implantable cardioverter defibrillator with low left ventricular ejection fraction.

PubMed

Jimenez-Juan, Laura; Karur, Gauri R; Connelly, Kim A; Deva, Djeven; Yan, Raymond T; Wald, Rachel M; Singh, Sheldon; Leung, General; Oikonomou, Anastasia; Dorian, Paul; Angaran, Paul; Yan, Andrew T

2017-04-01

Indications for the primary prevention of sudden death using an implantable cardioverter defibrillator (ICD) are based predominantly on left ventricular ejection fraction (LVEF). However, right ventricular ejection fraction (RVEF) is also a known prognostic factor in a variety of structural heart diseases that predispose to sudden cardiac death. We sought to investigate the relationship between right and left ventricular parameters (function and volume) measured by cardiovascular magnetic resonance (CMR) among a broad spectrum of patients considered for an ICD. In this retrospective, single tertiary-care center study, consecutive patients considered for ICD implantation who were referred for LVEF assessment by CMR were included. Right and left ventricular function and volumes were measured. In total, 102 patients (age 62±14 years; 23% women) had a mean LVEF of 28±11% and RVEF of 44±12%. The left ventricular and right ventricular end diastolic volume index was 140±42 mL/m 2 and 81±27 mL/m 2 , respectively. Eighty-six (84%) patients had a LVEF <35%, and 63 (62%) patients had right ventricular systolic dysfunction. Although there was a significant and moderate correlation between LVEF and RVEF ( r =0.40, p <0.001), 32 of 86 patients (37%) with LVEF <35% had preserved RVEF, while 9 of 16 patients (56%) with LVEF ≥35% had right ventricular systolic dysfunction (Kappa=0.041). Among patients being considered for an ICD, there is a positive but moderate correlation between LVEF and RVEF. A considerable proportion of patients who qualify for an ICD based on low LVEF have preserved RVEF, and vice versa.

Assessment of left ventricular myocardial deformation by cardiac MRI strain imaging reveals myocardial dysfunction in patients with primary cardiac tumors.

PubMed

Chen, Jing; Yang, Zhi-Gang; Xu, Hua-Yan; Shi, Ke; Guo, Ying-Kun

2018-02-15

To assess left ventricular myocardial deformation in patients with primary cardiac tumors. MRI was retrospectively performed in 61 patients, including 31 patients with primary cardiac tumors and 30 matched normal controls. Left ventricular strain and function parameters were then assessed by MRI-tissue tracking. Differences between the tumor group and controls, left and right heart tumor groups, left ventricular wall tumor and non-left ventricular wall tumor groups, and tumors with and without LV enlargement groups were assessed. Finally, the correlations among tumor diameter, myocardial strain, and LV function were analyzed. Left ventricular myocardial strain was milder for tumor group than for normal group. Peak circumferential strain (PCS) and its diastolic strain rate, longitudinal strains (PLS) and its diastolic strain rates, and peak radial systolic and diastolic velocities of the right heart tumor group were lower than those of the left heart tumor group (all p<0.050), but the peak radial systolic strain rate of the former was higher than that of the latter (p=0.017). The corresponding strains were lower in the left ventricular wall tumor groups than in the non-left ventricular wall tumor group (p<0.050). Peak radial systolic velocities were generally higher for tumors with LV enlargement than for tumors without LV enlargement (p<0.050). Peak radial strain, PCS, and PLS showed important correlations with the left ventricular ejection fraction (all p<0.050). MRI-tissue tracking is capable of quantitatively assessing left ventricular myocardial strain to reveal sub-clinical abnormalities of myocardial contractile function. Copyright © 2017 Elsevier B.V. All rights reserved.

Impella™ Left Ventricular Assist Device for Acute Peripartum Cardiomyopathy After Cesarean Delivery.

PubMed

Padilla, Cesar; Hernandez Conte, Antonio; Ramzy, Danny; Sanchez, Michael; Zhao, Manxu; Park, Donald; Lubin, Lorraine

2016-07-01

Peripartum cardiomyopathy is a rare form of heart failure with significant perioperative implications. In this case report, we describe a 34-year-old gravida 5, parity 3, patient who was admitted for an elective cesarean delivery. During the delivery, the patient developed sudden cardiac arrest and was emergently intubated in the operating room. An emergent transesophageal echocardiogram revealed a left ventricular ejection fraction of 10% with global biventricular hypokinesis. Urgent multidisciplinary consultations led to the rapid implementation of the Impella™ 2.5 for ventricular support. The patient recovered ventricular function within 4 days and recovered to baseline function.

Development of a compact wearable pneumatic drive unit for a ventricular assist device.

PubMed

Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Akagawa, Eiki; Lee, Hwansung; Nishinaka, Tomohiro; Takewa, Yoshiaki; Mizuno, Toshihide; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Shimosaki, Isao; Hamada, Shigeru; Mukaibayashi, Hiroshi; Iwaoka, Wataru

2008-01-01

The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.

Left ventricular assist device exchange: the Toronto General Hospital experience.

PubMed

Tsubota, Hideki; Ribeiro, Roberto V P; Billia, Filio; Cusimano, Robert J; Yau, Terrence M; Badiwala, Mitesh V; Stansfield, William E; Rao, Vivek

2017-08-01

As support times for left ventricular assist devices (LVADs) become longer, several complications requiring device exchange may occur. To our knowledge, this is the first Canadian report regarding implantable LVAD exchange. We retrospectively reviewed the cases of consecutive, unique patients implanted with an LVAD between June 2006 and October 2015 at Toronto General Hospital. In total, 122 patients were impanted with an LVAD during the study period. Eight patients required LVAD exchange, and 1 patient had 2 replacements (9 of 122, 7.3%). There were 7 HeartMate II (HMII), 1 HVAD and 1 DuraHeart pumps exchanged. Two of these exchanges occurred early at the time of initial implant, whereas 7 occurred late (range 8-623 d). Six exchanges were made owing to pump thrombosis. Of the 3 exchanges made for other causes, 1 HMII exchange was owing to a driveline fracture, 1 DuraHeart patient had early inflow obstruction requiring exchange to HMII at the initial implant, and the third had a suspected inflow obstruction with no evidence of thrombosis at the time of the procedure. The mean support time before exchange was 225 days, and time from exchange to transplant, death or ongoing support was 245 days. Three patients were successfully bridged to transplant, and at the time of data collection 2 were supported awaiting transplant. Three patients died after a mean duration of 394.3 days (range 78-673 d) of support postreplacement. Four cases were successfully performed using a subcostal approach. Pump thrombosis is the most common cause for LVAD exchange, which can be performed with acceptable morbidity and mortality. The subcostal approach may be the preferred procedure for an HMII exchange when indicated.

Totally implantable total artificial heart and ventricular assist device with multipurpose miniature electromechanical energy system.

PubMed

Takatani, S; Orime, Y; Tasai, K; Ohara, Y; Naito, K; Mizuguchi, K; Makinouchi, K; Damm, G; Glueck, J; Ling, J

1994-01-01

A multipurpose miniature electromechanical energy system has been developed to yield a compact, efficient, durable, and biocompatible total artificial heart (TAH) and ventricular assist device (VAD). Associated controller-driver electronics were recently miniaturized and converted into hybrid circuits. The hybrid controller consists of a microprocessor and controller, motor driver, Hall sensor, and commutation circuit hybrids. The sizing study demonstrated that all these components can be incorporated in the pumping unit of the TAH and VAD, particularly in the centerpiece of the TAH and the motor housing of the VAD. Both TAH and VAD pumping units will start when their power line is connected to either the internal power pack or the external battery unit. As a redundant driving and diagnostic port, an emergency port was newly added and will be placed in subcutaneous location. In case of system failure, the skin will be cut down, and an external motor drive or a pneumatic driver will be connected to this port to run the TAH. This will minimize the circulatory arrest time. Overall efficiency of the TAH without the transcutaneous energy transmission system was 14-18% to deliver pump outputs of 4-9 L/min against the right and left afterload pressures of 25 and 100 mm Hg. The internal power requirement ranged from 6 to 13 W. The rechargeable batteries such as NiCd or NiMH with 1 AH capacity can run the TAH for 30-45 min. The external power requirement, when TETS efficiency of 75% was assumed, ranged from 8 to 18 W. The accelerated endurance test in the 42 degrees C saline bath demonstrated stable performance over 4 months. Long-term endurance and chronic animal studies will continue toward a system with 5 years durability by the year 2000.

Sudden cardiac death and pump failure death prediction in chronic heart failure by combining ECG and clinical markers in an integrated risk model

PubMed Central

Orini, Michele; Mincholé, Ana; Monasterio, Violeta; Cygankiewicz, Iwona; Bayés de Luna, Antonio; Martínez, Juan Pablo

2017-01-01

Background Sudden cardiac death (SCD) and pump failure death (PFD) are common endpoints in chronic heart failure (CHF) patients, but prevention strategies are different. Currently used tools to specifically predict these endpoints are limited. We developed risk models to specifically assess SCD and PFD risk in CHF by combining ECG markers and clinical variables. Methods The relation of clinical and ECG markers with SCD and PFD risk was assessed in 597 patients enrolled in the MUSIC (MUerte Súbita en Insuficiencia Cardiaca) study. ECG indices included: turbulence slope (TS), reflecting autonomic dysfunction; T-wave alternans (TWA), reflecting ventricular repolarization instability; and T-peak-to-end restitution (ΔαTpe) and T-wave morphology restitution (TMR), both reflecting changes in dispersion of repolarization due to heart rate changes. Standard clinical indices were also included. Results The indices with the greatest SCD prognostic impact were gender, New York Heart Association (NYHA) class, left ventricular ejection fraction, TWA, ΔαTpe and TMR. For PFD, the indices were diabetes, NYHA class, ΔαTpe and TS. Using a model with only clinical variables, the hazard ratios (HRs) for SCD and PFD for patients in the high-risk group (fifth quintile of risk score) with respect to patients in the low-risk group (first and second quintiles of risk score) were both greater than 4. HRs for SCD and PFD increased to 9 and 11 when using a model including only ECG markers, and to 14 and 13, when combining clinical and ECG markers. Conclusion The inclusion of ECG markers capturing complementary pro-arrhythmic and pump failure mechanisms into risk models based only on standard clinical variables substantially improves prediction of SCD and PFD in CHF patients. PMID:29020031

Innovative Free-range Resonant Electrical Energy Delivery system (FREE-D System) for a ventricular assist device using wireless power.

PubMed

Waters, Benjamin H; Smith, Joshua R; Bonde, Pramod

2014-01-01

Technological innovation of a smaller, single moving part has an advantage over earlier large pulsatile ventricular assist devices (VADs) prone to mechanical failure. Drivelines limit the potential for extended patient survival durations with newer pumps and act as source for infection, increased morbidity, rehospitalizations, and reduced quality of life. The Free-range Resonant Electrical Energy Delivery (FREE-D) wireless power system uses magnetically coupled resonators to efficiently transfer power. We demonstrate the efficiency over distance of this system. The experimental setup consists of an radiofrequency amplifier and control board which drives the transmit resonator coil, and a receiver unit consisting of a resonant coil attached to a radiofrequency rectifier and power management module. The power management module supplies power to the axial pump, which was set at 9,600 rpm. To achieve a seamless wireless delivery in any room size, we introduced a third relay coil. This relay coil can be installed throughout a room, whereas a single relay coil could be built into a jacket worn by the patient, which would always be within range of the receive coil implanted in the patient's body. The power was delivered over a meter distance without interruptions or fluctuations with coil, rectifier, and regulator efficiency more than 80% and overall system efficiency of 61%. The axial pump worked well throughout the 8 hours of continuous operation. Having same setup on the opposite side can double the distance. A tether-free operation of a VAD can be achieved by FREE-D system in room-size distances. It has the potential to make the VAD therapy more acceptable from the patient perspective.

Sudden cardiac death and pump failure death prediction in chronic heart failure by combining ECG and clinical markers in an integrated risk model.

PubMed

Ramírez, Julia; Orini, Michele; Mincholé, Ana; Monasterio, Violeta; Cygankiewicz, Iwona; Bayés de Luna, Antonio; Martínez, Juan Pablo; Laguna, Pablo; Pueyo, Esther

2017-01-01

Sudden cardiac death (SCD) and pump failure death (PFD) are common endpoints in chronic heart failure (CHF) patients, but prevention strategies are different. Currently used tools to specifically predict these endpoints are limited. We developed risk models to specifically assess SCD and PFD risk in CHF by combining ECG markers and clinical variables. The relation of clinical and ECG markers with SCD and PFD risk was assessed in 597 patients enrolled in the MUSIC (MUerte Súbita en Insuficiencia Cardiaca) study. ECG indices included: turbulence slope (TS), reflecting autonomic dysfunction; T-wave alternans (TWA), reflecting ventricular repolarization instability; and T-peak-to-end restitution (ΔαTpe) and T-wave morphology restitution (TMR), both reflecting changes in dispersion of repolarization due to heart rate changes. Standard clinical indices were also included. The indices with the greatest SCD prognostic impact were gender, New York Heart Association (NYHA) class, left ventricular ejection fraction, TWA, ΔαTpe and TMR. For PFD, the indices were diabetes, NYHA class, ΔαTpe and TS. Using a model with only clinical variables, the hazard ratios (HRs) for SCD and PFD for patients in the high-risk group (fifth quintile of risk score) with respect to patients in the low-risk group (first and second quintiles of risk score) were both greater than 4. HRs for SCD and PFD increased to 9 and 11 when using a model including only ECG markers, and to 14 and 13, when combining clinical and ECG markers. The inclusion of ECG markers capturing complementary pro-arrhythmic and pump failure mechanisms into risk models based only on standard clinical variables substantially improves prediction of SCD and PFD in CHF patients.

Institutional Cost Comparison Between Heart Transplants and Left Ventricular Assist Device Implantations.

PubMed

Chimanji, Neeraj; Kilic, Arman; Hasan, Ayesha; Higgins, Robert S D; Whitson, Bryan A; Kilic, Ahmet

2016-12-01

Increased numbers of end-stage heart failure patients and improved technology have led to increased use of left ventricular assist devices as a viable alternative to heart transplants. Given the current economic climate, we compared costs of heart transplant versus device placement. Medical records of patients who received heart transplants or left ventricular assist devices were cross-referenced with institutional financial data. The device cohort was limited to those receiving durable (not temporary) devices. Index admission, 1-year readmission, and overall 1-year charges were compared using standard statistical methods. Of 184 identified patients with end-stage heart failure surgical therapy, 121 received left ventricular assist devices, 43 had heart transplants, and 20 received left ventricular assist devices as bridge to heart transplant; these latter patients were excluded from our analyses. At index admission, mean charges were $863 433 ± $398 427 for device patients and $725 877 ± $488 685 for transplant patients (P = .05). One-year mean readmission rates were similar (4.65/transplant patient and 4.53/device patient; P = .94), with corresponding 1-year survival rates of 87.8% and 78.0% (P = .04). Total readmission charges during year 1 were $169 732 ± $242 366 for device patients and $201 682 ± $297 565 for transplant patients (P = .08), with corresponding overall charges at 1 year of $1 029 732 ± $450 498 and $927 559 ± $562 404 (P = .49). During the first year, heart transplant and left ventricular assist device placement have similar costs. Initial index admission costs seem to favor heart transplant, with device pump costs accounting for some of the difference. From a 1-year survival perspective, heart transplant may be more effective; however, with lack of suitable donors, left ventricular assist devices are valuable in the armamentarium of advanced heart failure surgical options.

In vivo testing of a magnetically suspended centrifugal pump designed for long-term use.

PubMed

Yamada, T; Nishimura, K; Akamatsu, T; Tsukiya, T; Park, C H; Kono, S; Matsuda, K; Ban, T

1997-10-01

The life of currently-available centrifugal pumps is limited to no more than three days. As a magnetically suspended centrifugal pump (MSCP) contains no shaft or seal, it could be expected to have a longer life expectancy. The MSCP was evaluated in a chronic animal model using eight adult sheep. Left ventricular assist with the MSCP was instituted between the left atrium and the descending aorta. The flow rates ranged from 2.5 to 6.0 L/min. The duration of the experiments ranged from 14 to 60 days. No mechanical failure occurred. The plasma free hemoglobin levels remained within an acceptable range (3-19 mg/dL). No reduction in the counts of red blood cells or platelets was observed. Thrombus formation within the MSCP was recognized in one pump. The main reason for termination was thromboembolism derived from the circuits. Three types of regulation methods (constant rotational speed, constant motor current, and controlled motor current) were also investigated. Regulation by a constant motor current mode altered the pressure-flow (P-Q) characteristics, and thereby, a steadier pump flow was obtained compared with regulation in the constant rotational speed mode. Moreover, the controlled motor current mode can change the P-Q relationship. These results demonstrate that the MSCP is a promising device for long-term use.

Classification of Unsteady Flow Patterns in a Rotodynamic Blood Pump: Introduction of Non-Dimensional Regime Map.

PubMed

Shu, Fangjun; Vandenberghe, Stijn; Brackett, Jaclyn; Antaki, James F

2015-09-01

Rotodynamic blood pumps (also known as rotary or continuous flow blood pumps) are commonly evaluated in vitro under steady flow conditions. However, when these devices are used clinically as ventricular assist devices (VADs), the flow is pulsatile due to the contribution of the native heart. This study investigated the influence of this unsteady flow upon the internal hemodynamics of a centrifugal blood pump. The flow field within the median axial plane of the flow path was visualized with particle image velocimetry (PIV) using a transparent replica of the Levacor VAD. The replica was inserted in a dynamic cardiovascular simulator that synchronized the image acquisition to the cardiac cycle. As compared to steady flow, pulsatile conditions produced periodic, transient recirculation regions within the impeller and separation in the outlet diffuser. Dimensional analysis revealed that the flow characteristics could be uniquely described by the non-dimensional flow coefficient (Φ) and its time derivative ([Formula: see text]), thereby eliminating impeller speed from the experimental matrix. Four regimes within the Φ-[Formula: see text] plane were found to classify the flow patterns, well-attached or disturbed. These results and methods can be generalized to provide insights for both design and operation of rotodynamic blood pumps for safety and efficacy.

[Evaluation of left ventricular diastolic function in canine acute myocardial ischemia using velocity vector imaging and quantitative tissue velocity imaging].

PubMed

Zhang, Chuan; Zha, Dao-Gang; DU, Rong-Sheng; Hu, Feng; Li, Sheng-Hui; Wu, Xiao-Yuan; Liu, Yi-Li

2009-07-01

To assess the value of velocity vector imaging (VVI) and quantitative tissue velocity imaging (QTVI) in assessing left ventricular diastolic function of the dogs with acute myocardial ischemia. Six healthy mongrel dogs were subjected to ligation of the left circumflex artery or left anterior descending artery to induce coronary artery stenosis of varying degrees. The mean peak diastolic velocity (Em) of the ventricular walls around the mitral annulus was recorded with VVI or QTVI in the coronary blood flow. The left ventricular end diastolic pressure (LVEDP) was measured with pigtail catheter in the left ventricle. As the coronary blood flow decreased, LVEDP was gradually increased, and Em measured by VVI or QTVI were also gradually decreased. A good linear correlation was shown between Em measured by VVI or QTVI and LVEDP (r=-0.834, P<0.001, and r=-0.68, P<0.001, respectively). A significant difference was observed in the correlation coefficient between VVI and QTVI (Z=2.625, P=0.0087). VVI and QTVI both provide good noninvasive means for measuring left ventricular diastolic function. VVI, a new echocardiographic modality without angular dependence, is better than QTVI in evaluating left ventricular diastolic function.

Left ventricular early diastolic inflow velocity and atrial ventricular plane downward velocity: useful parameters to test diastolic function in clinical practice? Diastolic parameters tested in a clinical setting.

PubMed

Winter, R; Gudmundsson, P; Ericsson, G; Willenheimer, R

2001-06-01

To study the clinical value of the colour-M-mode slope of the early diastolic left ventricular filling phase (Vp) and the early diastolic downward M-mode slope of the left atrioventricular plane displacement (EDS), compared with diastolic function assessed by traditional Doppler evaluation. In 65 consecutive patients EDS and Vp were compared with a four-degree traditional diastolic function classification, based on pulsed Doppler assessment of the early to atrial transmitral flow ratio (E/A), the E-wave deceleration time (Edt), and the systolic to diastolic (S/D) pulmonary venous inflow ratio. Vp (P=0.006) and EDS (P=0.045) were related to traditional diastolic function (Kruskal--Wallis analysis). EDS showed a trend brake between the moderate and severe diastolic dysfunction groups by traditional Doppler evaluation. Vp and EDS correlated weakly in simple linear regression analysis (r=0.33). Vp and EDS discriminated poorly between normal and highly abnormal diastolic function. Vp and EDS were significantly related to diastolic function by traditional Doppler evaluation. They were, however, not useful as single parameters of left ventricular diastolic function due to a small difference between normal and highly abnormal values, allowing for little between-measurement variability. Consequently, these methods for the evaluation of left ventricular diastolic function do not add significantly to traditional Doppler evaluation.

High-pressure portable pneumatic drive unit.

PubMed

Hete, B F; Savage, M; Batur, C; Smith, W A; Golding, L A; Nosé, Y

1989-12-01

The left ventricular assist device (LVAD) of the Cleveland Clinic Foundation (CCF) is a single-chamber assist pump, driven by a high-pressure pneumatic cylinder. A low-cost, portable driver that will allow cardiac care patients, with a high-pressure pneumatic ventricle assist, more freedom of movement has been developed. The compact and light-weight configuration can provide periods of 2 h of freedom from a fixed position driver and does not use exotic technology.

Radiology of cardiac devices and their complications

PubMed Central

Dipoce, J; Spindola-Franco, H

2015-01-01

This article familiarizes the reader with several different cardiac devices including pacemakers and implantable cardioverter defibrillators, intra-aortic balloon pumps, ventricular assist devices, valve replacements and repairs, shunt-occluding devices and passive constraint devices. Many cardiac devices are routinely encountered in clinical practice. Other devices are in the early stages of development, but circumstances suggest that they too will become commonly found. The radiologist must be familiar with these devices and their complications. PMID:25411826

Fluid mechanics of blood flow in human fetal left ventricles based on patient-specific 4D ultrasound scans.

PubMed

Lai, Chang Quan; Lim, Guat Ling; Jamil, Muhammad; Mattar, Citra Nurfarah Zaini; Biswas, Arijit; Yap, Choon Hwai

2016-10-01

The mechanics of intracardiac blood flow and the epigenetic influence it exerts over the heart function have been the subjects of intense research lately. Fetal intracardiac flows are especially useful for gaining insights into the development of congenital heart diseases, but have not received due attention thus far, most likely because of technical difficulties in collecting sufficient intracardiac flow data in a safe manner. Here, we circumvent such obstacles by employing 4D STIC ultrasound scans to quantify the fetal heart motion in three normal 20-week fetuses, subsequently performing 3D computational fluid dynamics simulations on the left ventricles based on these patient-specific heart movements. Analysis of the simulation results shows that there are significant differences between fetal and adult ventricular blood flows which arise because of dissimilar heart morphology, E/A ratio, diastolic-systolic duration ratio, and heart rate. The formations of ventricular vortex rings were observed for both E- and A-wave in the flow simulations. These vortices had sufficient momentum to last until the end of diastole and were responsible for generating significant wall shear stresses on the myocardial endothelium, as well as helicity in systolic outflow. Based on findings from previous studies, we hypothesized that these vortex-induced flow properties play an important role in sustaining the efficiency of diastolic filling, systolic pumping, and cardiovascular flow in normal fetal hearts.

Experience of a patient with an extracorporeal ventricular assist system who participated in a sleepover program.

PubMed

Gon, Shigeyoshi; Suematsu, Yoshihito; Morizumi, Sei; Shimizu, Tsuyoshi

2011-09-01

A 19-year-old woman suffered fulminant myocarditis owing to a mycoplasma infection and was inserted with an intra-aortic balloon pump and a percutaneous cardiopulmonary support. Antibiotics and gamma globulin were administered, however, the patient's cardiac function did not recover, and the TOYOBO ventricular assist device (VAD) was implanted. She had rehabilitation training such as maintaining a standing position at the bedside and walking in the hospital, and a hospital outing program to a family restaurant was conducted two times with the VAD. The patient wished to attend the coming-of-age ceremony in Tachikawa city, which is 3 h away from our hospital by car. Therefore, we planned the program including a night stay at her home. The patient and her family fully understood the risks and wished to participate in the sleepover program. In preparing for the sleepover, the patient and her family learned to operate the VAD, and she was able to move to the lavatory and through the house with the help of only her family. A physician and a clinical engineer stayed at her house for infusion of antibiotics and management of sudden changes. There was no adverse event. In Japan, the community support of patients with VAD is not yet established, and we hope that our experience becomes a help to support return to society for patients with VAD.

Assessment of Bleeding and Thrombosis Based on Aspirin Responsiveness after Continuous-Flow Left Ventricular Assist Device Placement.

PubMed

Floroff, Catherine K; Rieger, Krista L; Veasey, Tara M; Strout, Sara E; DeNino, Walter F; Meadows, Holly B; Stroud, Martha R; Toole, John M; Heyward, Dawn P; Brisco-Bacik, Meredith A; Cook, Jennifer L; Lazarchick, John; Uber, Walter E

Pump thrombosis (PT) is a severe complication of left ventricular assist device (LVAD) support. This study evaluated PT and bleeding after LVAD placement in patients responsive to a standard aspirin dose of 81 mg using platelet inhibition monitoring compared with initial nonresponders who were then titrated upward to achieve therapeutic response. Patients ≥ 18 years of age with initial placement of HeartMate II LVAD at our institution and at least one VerifyNow Aspirin test performed during initial hospitalization were included. The primary endpoints were bleeding and PT compared between initial aspirin responders and nonresponders. Of 85 patients, 19 (22%) were nonresponsive to initial aspirin therapy. Responders and nonresponders showed similar survival (p = 0.082), freedom from suspected/confirmed PT (p = 0.941), confirmed PT (p = 0.273), bleeding (p = 0.401), and incidence rates in PT and bleeding. Among the initial responders (<500 vs. 500-549 aspirin reaction units), there were no significant differences in survival (p = 0.177), freedom from suspected/confirmed PT (p = 0.542), confirmed PT (p = 0.159), bleeding (p = 0.879), and incidence of PT and bleeding. Platelet function testing may detect resistance to standard aspirin regimens used in LVAD patients. Dose escalation in initially nonresponsive patients to achieve responsiveness may confer a similar PT risk to patients initially responsive to standard aspirin dosing without increased bleeding risk.

Modification of the BioMedicus centrifugal pump to provide continuous irrigation for neuroendoscopy: technical note.

PubMed

Koueik, Joyce; Rocque, Brandon G; Henry, Jordan; Bragg, Taryn; Paul, Jennifer; Iskandar, Bermans J

2018-02-01

Continuous irrigation is an important adjunct for successful intraventricular endoscopy, particularly for complex cases. It allows better visualization by washing out blood and debris, improves navigation by expanding the ventricles, and assists with tissue dissection. A method of irrigation delivery using a centrifugal pump designed originally for cardiac surgery is presented. The BioMedicus centrifugal pump has the desirable ability to deliver a continuous laminar flow of fluid that excludes air from the system. A series of modifications to the pump tubing was performed to adapt it to neuroendoscopy. Equipment testing determined flow and pressure responses at various settings and simulated clinical conditions. The pump was then studied clinically in 11 endoscopy cases and eventually used in 310 surgical cases. Modifications of the pump tubing allowed for integration with different endoscopy systems. Constant flow rates were achieved with and without surgical instruments through the working ports. Optimal flow rates ranged between 30 and 100 ml/min depending on endoscope size. Intraoperative use was well tolerated with no permanent morbidity and showed consistent flow rates, minimal air accumulation, and seamless irrigation bag replacement during prolonged surgery. Although the pump is equipped with an internal safety mechanism to protect against pressure buildup when outflow obstructions occur, equipment testing revealed that flow cessation is not instantaneous enough to protect against sudden intracranial pressure elevation. A commonly available cardiac pump system was modified to provide continuous irrigation for intraventricular endoscopy. The system alleviates the problems of inconsistent flow rates, air in the irrigation lines, and delays in changing irrigation bags, thereby optimizing patient safety and surgical efficiency. Safe use of the pump requires good ventricular outflow and, clearly, sound surgical judgment.

Speckle tracking evaluation of right ventricular functions in children with sickle cell disease.

PubMed

Tolba, Osama Abd Rab Elrasol; El-Shanshory, Mohamed Ramadan; El-Gamasy, Mohamed Abd Elaziz; El-Shehaby, Walid Ahmed

2017-01-01

Cardiac dysfunction is a risk factor for death in patients with sickle cell disease (SCD). Aim of the work is to evaluate the right ventricular systolic and diastolic functions by tissue Doppler and speckling tracking imaging in children with SCD. Thirty children with SCD and thirty controls were subjected to clinical, laboratory evaluations, and echocardiographic study using GE Vivid 7 (GE Medical System, Horten, Norway with a 3.5-MHz multifrequency transducer) including; Two-dimensional and tissue Doppler echocardiographic study (lateral tricuspid valve annulus peak E' velocity, lateral tricuspid valve annulus peak A' velocity, E'/A' ratio, isovolumetric relaxation time, lateral tricuspid valve annulus S' and septal S' waves and peak longitudinal systolic strain [PLSS] and time to PLSS) were done in six right ventricular segments. There was a significant decrease in right ventricular systolic and diastolic function in patients group when compared to controls. Children with SCD have impaired right ventricular systolic and diastolic functions when compared to healthy children with early evaluation of the systolic dysfunction by speckle tracking imaging technique.

Change of heart dimensions and function during pregnancy in goats.

PubMed

Szaluś-Jordanow, Olga; Czopowicz, Michał; Witkowski, Lucjan; Moroz, Agata; Mickiewicz, Marcin; Frymus, Tadeusz; Markowska-Daniel, Iwona; Bagnicka, Emilia; Kaba, Jarosław

2018-03-08

The study aimed to evaluate the effect of pregnancy on heart diameters and function in goats. Transthoracic echocardiography of 12 female dairy goats of two Polish regional breeds was performed. A Mindray M7 diagnostic ultrasound system with Phased Array transducer was used. Simultaneously, electrocardiography was recorded. All animals were examined four times - at mating season, at the end of the first trimester, at the end of the second trimester and just before kidding. Eleven measurements were taken each time: aortic and left atrial diameter (AoD and LAD), right and left ventricular internal diameter in diastole (RVIDd and LVIDd), left ventricular internal diameter in systole (LVIDs), inter-ventricular septum thickness in diastole and systole (IVSd and IVSd) and left ventricular posterior wall in diastole and systole (LVPWd and LVPWs), maximum left and right ventricular outflow tract velocity (RVOT Vmax and LVOT Vmax). Nine consecutive measurements were derived: the ratio of the left atrial diameter to the aortic diameter (AoD/LAD), left ventricular fractional shortening (FS%), left ventricular ejection fraction (EF%), maximum outflow tract pressure gradients (RVOT PGmax and LVOT PGmax), left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV), stroke volume (SV) and cardiac output (CO). HR, LAD, LVPWs, IVSs increased significantly in the first trimester. AoD and RVIDd were significantly higher around parturition. LVIDd, FS%, EF%, SV and CO rose both in the first and third trimester. No measurement decreased during pregnancy. The study confirms that pregnancy causes changes in the heart size and functioning. Copyright © 2018. Published by Elsevier Ltd.

Bridge to transplantation with a left ventricular assist device.

PubMed

Jung, Jae Jun; Sung, Kiick; Jeong, Dong Seop; Kim, Wook Sung; Lee, Young Tak; Park, Pyo Won

2012-04-01

A 61-year-old female patient was diagnosed with dilated cardiomyopathy with severe left ventricle dysfunction. Two days after admission, continuous renal replacement therapy was performed due to oliguria and lactic acidosis. On the fifth day, an intra-aortic balloon pump was inserted due to low cardiac output syndrome. Beginning 4 days after admission, she was supported for 15 days thereafter with an extracorporeal left ventricular assist device (LVAD) because of heart failure with multi-organ failure. A heart transplant was performed while the patient was stabilized with the LVAD. She developed several complications after the surgery, such as cytomegalovirus pneumonia, pulmonary tuberculosis, wound dehiscence, and H1N1 infection. On postoperative day 19, she was discharged from the hospital with close follow-up and treatment for infection. She received follow-up care for 10 months without any immune rejection reaction.

Arrhythmogenic Right Ventricular Cardiomyopathy in an Endurance Athlete Presenting with Ventricular Tachycardia and Normal Right Ventricular Function.

PubMed

Hedley, Jeffrey S; Al Mheid, Ibhar; Alikhani, Zoubin; Pernetz, Maria A; Kim, Jonathan H

2017-08-01

Arrhythmogenic right ventricular cardiomyopathy, a genetically inherited disease that results in fibrofatty replacement of normal cardiac myocytes, has been associated with sudden cardiac death in athletes. Long-term participation in endurance exercise hastens the development of both the arrhythmic and structural arrhythmogenic right ventricular cardiomyopathy phenotypes. We describe the unusual case of a 34-year-old, symptomatic, female endurance athlete who had arrhythmogenic right ventricular cardiomyopathy in the presence of a structurally normal right ventricle. Clinicians should be aware of this infrequent presentation when evaluating athletic patients who have ventricular arrhythmias and normal findings on cardiac imaging studies.

Three-Dimensional Right Ventricular Strain Versus Volume Quantification in Heart Transplant Recipients in Relation to Pulmonary Artery Pressure.

PubMed

Sade, Leyla Elif; Kozan, Hatice; Eroglu, Serpil; Pirat, Bahar; Aydinalp, Alp; Sezgin, Atilla; Muderrisoglu, Haldun

2017-02-01

Residual pulmonary hypertension challenges the right ventricular function and worsens the prognosis in heart transplant recipients. The complex geometry of the right ventricle complicates estimation of its function with conventional transthoracic echocardiography. We evaluated right ventricular function in heart transplant recipients with the use of 3-dimensional echocardiography in relation to systolic pulmonary artery pressure. We performed 32 studies in 26 heart transplant patients, with 6 patients having 2 studies at different time points with different pressures and thus included. Right atrial volume, tricuspid annular plane systolic excursion, peak systolic annular velocity, fractional area change, and 2-dimensional speckle tracking longitudinal strain were obtained by 2-dimensional and tissue Doppler imaging. Three-dimensional right ventricular volumes, ejection fraction, and 3-dimensional right ventricular strain were obtained from the 3-dimensional data set by echocardiographers. Systolic pulmonary artery pressure was obtained during right heart catheterization. Overall mean systolic pulmonary artery pressure was 26 ± 7 mm Hg (range, 14-44 mmHg). Three-dimensional end-diastolic (r = 0.75; P < .001) and end-systolic volumes (r = 0.55; P = .001)correlated well with systolic pulmonary artery pressure. Right ventricular ejection fraction and right atrium volume also significantly correlated with systolic pulmonary artery pressure (r = 0.49 and P = .01 for both). However, right ventricular 2- and 3-dimensional strain, tricuspid annular plane systolic excursion, and tricuspid annular velocity did not. The effects of pulmonary hemodynamic burden on right ventricular function are better estimated by a 3-dimensional volume evaluation than with 3-dimensional longitudinal strain and other 2-dimensional and tissue Doppler measurements. These results suggest that the peculiar anatomy of the right ventricle necessitates 3-dimensional volume quantification in heart transplant recipients in relation to residual pulmonary hypertension.

Is Doppler tissue velocity during early left ventricular filling preload independent?

NASA Technical Reports Server (NTRS)

Yalcin, F.; Kaftan, A.; Muderrisoglu, H.; Korkmaz, M. E.; Flachskampf, F.; Garcia, M.; Thomas, J. D.

2002-01-01

BACKGROUND: Transmitral Doppler flow indices are used to evaluate diastolic function. Recently, velocities measured by Doppler tissue imaging have been used as an index of left ventricular relaxation. OBJECTIVE: To determine whether Doppler tissue velocities are influenced by alterations in preload. METHODS: Left ventricular preload was altered in 17 patients (all men, mean (SD) age, 49 (8) years) during echocardiographic measurements of left ventricular end diastolic volume, maximum left atrial area, peak early Doppler filling velocity, and left ventricular myocardial velocities during early filling. Preload altering manoeuvres included Trendelenberg (stage 1), reverse Trendelenberg (stage 2), and amyl nitrate (stage 3). Systolic blood pressure was measured at each stage. RESULTS: In comparison with baseline, left ventricular end diastolic volume (p = 0.001), left atrial area (p = 0.003), peak early mitral Doppler filling velocity (p = 0.01), and systolic blood pressures (p = 0.001) were all changed by preload altering manoeuvres. Only left ventricular myocardial velocity during early filling remained unchanged by these manoeuvres. CONCLUSIONS: In contrast to standard transmitral Doppler filling indices, Doppler tissue early diastolic velocities are not significantly affected by physiological manoeuvres that alter preload. Thus Doppler tissue velocities during early left ventricular diastole may provide a better index of diastolic function in cardiac patients by providing a preload independent assessment of left ventricular filling.

Right ventricular morphology and function in chronic obstructive pulmonary disease patients living at high altitude.

PubMed

Güvenç, Tolga Sinan; Erer, Hatice Betül; Kul, Seref; Perinçek, Gökhan; Ilhan, Sami; Sayar, Nurten; Yıldırım, Binnaz Zeynep; Doğan, Coşkun; Karabağ, Yavuz; Balcı, Bahattin; Eren, Mehmet

2013-01-01

Pulmonary vasculature is affected in patients with chronic pulmonary obstructive disease (COPD). As a result of increased pulmonary resistance, right ventricular morphology and function are altered in COPD patients. High altitude and related hypoxia causes pulmonary vasoconstriction, thereby affecting the right ventricle. We aimed to investigate the combined effects of COPD and altitude-related chronic hypoxia on right ventricular morphology and function. Forty COPD patients living at high altitude (1768 m) and 41 COPD patients living at sea level were enrolled in the study. All participants were diagnosed as COPD by a pulmonary diseases specialist depending on symptoms, radiologic findings and pulmonary function test results. Detailed two-dimensional echocardiography was performed by a cardiologist at both study locations. Oxygen saturation and mean pulmonary artery pressure were higher in the high altitude group. Right ventricular end diastolic diameter, end systolic diameter, height and end systolic area were significantly higher in the high altitude group compared to the sea level group. Parameters of systolic function, including tricuspid annular systolic excursion, systolic velocity of tricuspid annulus and right ventricular isovolumic acceleration were similar between groups, while fractional area change was significantly higher in the sea level groups compared to the high altitude group. Indices of diastolic function and myocardial performance index were similar between groups. An increase in mean pulmonary artery pressure and right ventricular dimensions are observed in COPD patients living at high altitude. Despite this increase, systolic and diastolic functions of the right ventricle, as well as global right ventricular performance are similar in COPD patients living at high altitude and sea level. Altitude-related adaptation to chronic hypoxia could explain these findings. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Acute decrease of left ventricular mechanical dyssynchrony and improvement of contractile state and energy efficiency after left ventricular restoration.

PubMed

Schreuder, Jan J; Castiglioni, Alessandro; Maisano, Francesco; Steendijk, Paul; Donelli, Andrea; Baan, Jan; Alfieri, Ottavio

2005-01-01

Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency. Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a conductance volume catheter to analyze pressure-volume relationships, energy efficiency, and mechanical dyssynchrony. The end-systolic elastance was used as a load-independent index of contractile state. Left ventricular energy efficiency was calculated from stroke work and total pressure-volume area. Segmental volume changes perpendicular to the long axis were used to calculate mechanical dyssynchrony. Statistical analysis was performed with the paired t test and least-squares linear regression. Endoventricular patch aneurysmectomy reduced end-diastolic volume by 37% (P < .001), with unchanged stroke volume. Systolic function improved, as derived from increased +dP/dt(max), by 42% (P < .03), peak ejection rate by 28% (P < .02), and ejection fraction by 16% (P < .0002). Early diastolic function improved, as shown by reduction of -dP/dt(max) by 34% (P < .006) and shortened tau by 30% (P < .001). Left ventricular end-systolic elastance increased from 1.2 +/- 0.6 to 2.2 +/- 1 mm Hg/mL (P < .001). Left ventricular energy efficiency increased by 36% (P < .002). Left ventricular mechanical dyssynchrony decreased during systole by 33% (P < .001) and during diastole by 20% (P < .005). Left ventricular restoration induced acute improvements in contractile state, energy efficiency, and relaxation, together with a decrease in left ventricular mechanical dyssynchrony.

Effects of Obesity on Cardiovascular Hemodynamics, Cardiac Morphology, and Ventricular Function.

PubMed

Alpert, Martin A; Omran, Jad; Bostick, Brian P

2016-12-01

Obesity produces a variety of hemodynamic alterations that may cause changes in cardiac morphology which predispose to left and right ventricular dysfunction. Various neurohormonal and metabolic alterations commonly associated with obesity may contribute to these abnormalities of cardiac structure and function. These changes in cardiovascular hemodynamics, cardiac morphology, and ventricular function may, in severely obese patients, predispose to heart failure, even in the absence of other forms of heart disease (obesity cardiomyopathy). In normotensive obese patients, cardiac involvement is commonly characterized by elevated cardiac output, low peripheral vascular resistance, and increased left ventricular (LV) end-diastolic pressure. Sleep-disordered breathing may lead to pulmonary arterial hypertension and, in association with left heart failure, may contribute to elevation of right heart pressures. These alterations, in association with various neurohormonal and metabolic abnormalities, may produce LV hypertrophy; impaired LV diastolic function; and less commonly, LV systolic dysfunction. Many of these alterations are reversible with substantial voluntary weight loss.

Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: insight from a multi-scale model.

PubMed

Hermeling, Evelien; Delhaas, Tammo; Prinzen, Frits W; Kuijpers, Nico H L

2012-01-01

In the ECG, T- and R-wave are concordant during normal sinus rhythm (SR), but discordant after a period of ventricular pacing (VP). Experiments showed that the latter phenomenon, called T-wave memory, is mediated by a mechanical stimulus. By means of a mathematical model, we investigated the hypothesis that slow acting mechano-electrical feedback (MEF) explains T-wave memory. In our model, electromechanical behavior of the left ventricle (LV) was simulated using a series of mechanically and electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, and excitation-contraction coupling. MEF was incorporated by locally adjusting conductivity of L-type calcium current (g(CaL)) to local external work. In our set-up, g(CaL) could vary up to 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: normal SR (with MEF), acute VP, sustained VP (with MEF), and acutely restored SR. MEF led to T-wave concordance in normal SR and to discordant T-waves acutely after restoring SR. Simulated ECGs with a maximum of 25-50% adaptation closely resembled those during T-wave memory experiments in vivo and also provided the best compromise between optimal systolic and diastolic function. In conclusion, these simulation results indicate that slow acting MEF in the LV can explain a) the relatively small differences in systolic shortening and mechanical work during SR, b) the small dispersion in repolarization time, c) the concordant T-wave during SR, and d) T-wave memory. The physiological distribution in electrophysiological properties, reflected by the concordant T-wave, may serve to optimize cardiac pump function. Copyright © 2012 Elsevier Ltd. All rights reserved.

Aldosterone down-regulates the slowly activated delayed rectifier potassium current in adult guinea pig cardiomyocytes.

PubMed

Lv, Yankun; Bai, Song; Zhang, Hua; Zhang, Hongxue; Meng, Jing; Li, Li; Xu, Yanfang

2015-12-01

There is emerging evidence that the mineralocorticoid hormone aldosterone is associated with arrhythmias in cardiovascular disease. However, the effect of aldosterone on the slowly activated delayed rectifier potassium current (IK s ) remains poorly understood. The present study was designed to investigate the modulation of IK s by aldosterone. Adult guinea pigs were treated with aldosterone for 28 days via osmotic pumps. Standard glass microelectrode recordings and whole-cell patch-clamp techniques were used to record action potentials in papillary muscles and IK s in ventricular cardiomyocytes. The aldosterone-treated animals exhibited a prolongation of the QT interval and action potential duration with a higher incidence of early afterdepolarizations. Patch-clamp recordings showed a significant down-regulation of IK s density in the ventricular myocytes of these treated animals. These aldosterone-induced electrophysiological changes were fully prevented by a combined treatment with spironolactone, a mineralocorticoid receptor (MR) antagonist. In addition, in in vitro cultured ventricular cardiomyocytes, treatment with aldosterone (sustained exposure for 24 h) decreased the IK s density in a concentration-dependent manner. Furthermore, a significant corresponding reduction in the mRNA/protein expression of IKs channel pore and auxiliary subunits, KCNQ1 and KCNE1 was detected in ventricular tissue from the aldosterone-treated animals. Aldosterone down-regulates IK s by inhibiting the expression of KCNQ1 and KCNE1, thus delaying the ventricular repolarization. These results provide new insights into the mechanism underlying K(+) channel remodelling in heart disease and may explain the highly beneficial effects of MR antagonists in HF. © 2015 The British Pharmacological Society.

Flow-related Right Ventricular - Pulmonary Arterial Pressure Gradients during Exercise.

PubMed

Wright, Stephen P; Opotowsky, Alexander R; Buchan, Tayler A; Esfandiari, Sam; Granton, John T; Goodman, Jack M; Mak, Susanna

2018-06-06

The assumption of equivalence between right ventricular and pulmonary arterial systolic pressure is fundamental to several assessments of right ventricular or pulmonary vascular hemodynamic function. Our aims were to 1) determine whether systolic pressure gradients develop across the right ventricular outflow tract in healthy adults during exercise, 2) examine the potential correlates of such gradients, and 3) consider the effect of such gradients on calculated indices of right ventricular function. Healthy untrained and endurance-trained adult volunteers were studied using right-heart catheterization at rest and during submaximal cycle ergometry. Right ventricular and pulmonary artery pressures were simultaneously transduced, and cardiac output was determined by thermodilution. Systolic pressures, peak and mean gradients, and indices of chamber, vascular, and valve function were analyzed offline. Summary data are reported as mean ± standard deviation or median [interquartile range]. No significant right ventricular outflow tract gradients were observed at rest (mean gradient = 4 [3-5] mmHg), and calculated effective orifice area was 3.6±1.0 cm2. Right ventricular systolic pressure increases during exercise were greater than that of pulmonary artery systolic pressure. Accordingly, mean gradients developed during light exercise (8 [7-9] mmHg) and increased during moderate exercise (12 [9-14] mmHg, p < 0.001). The magnitude of the mean gradient was linearly related to cardiac output (r2 = 0.70, p < 0.001). In healthy adults without pulmonic stenosis, systolic pressure gradients develop during exercise, and the magnitude is related to blood flow rate.

[Left ventricular dysfunction measured in diabetic patients with chronic renal failure on continuous ambulatory peritoneal dialysis].

PubMed

Díaz-Arrieta, Gustavo; Mendoza-Hernández, María Elsa; Pacheco-Aranda, Erika; Rivas-Duro, Miguel; Robles-Parra, Héctor Manuel; Espinosa-Vázquez, Raúl Arturo; Hernández-Cabrera, Jorge

2010-01-01

In diabetic patients with chronic renal failure (CRF) treated with dialysis, the diastolic and systolic left ventricular dysfunction is frequent. The aim was to assess by echocardiography the prevalence of diastolic and systolic ventricular dysfunction in diabetic patients with CRF treated with continuous ambulatory peritoneal dialysis (CAPD). Sixty diabetic patients with CRF in CAPD were studied. The mean age was 54.5 +/- 12 years (27-78 years). The left ventricular filling pattern (LVFP) as a diastolic function parameter and left ventricular ejection fraction (LVEF) as a systolic function parameter were measured by transthoracic echocardiography. Descriptive statistical analysis was used. 27 (45 %) patients were women and 33 (55 %) were men. In 55 (91.7 %) left ventricular concentric hypertrophy was observed. Fifty-two patients (86.7 %) showed LVFP type I; three (5 %) had the type II; two (3.3 %) showed pseudonormal pattern and three (5 %) had a normal LVFP. The LVEF was 0.63 +/- 0.09 (CI = 0.41-0.82). Forty nine (81.7 %) patients had LVEF equal or greater than 0.55. The prevalence of diastolic left ventricular dysfunction was 95 % and the prevalence of systolic left ventricular dysfunction was 18.3%.

Diastolic dysfunction in hypertension.

PubMed

Nazário Leão, R; Marques da Silva, P

Hypertension and coronary heart disease, often coexisting, are the most common risk factors for heart failure. The progression of hypertensive heart disease involves myocardial fibrosis and alterations in the left ventricular geometry that precede the functional change, initially asymptomatic. The left ventricular diastolic dysfunction is part of this continuum being defined by the presence of left ventricular diastolic dysfunction without signs or symptoms of heart failure or poor left ventricular systolic function. It is highly prevalent in hypertensive patients and is associated with increased cardiovascular morbidity and mortality. Despite its growing importance in clinical practice it remains poorly understood. This review aims to present the epidemiological fundamentals and the latest developments in the pathophysiology, diagnosis and treatment of left ventricular diastolic dysfunction. Copyright © 2017 SEH-LELHA. Publicado por Elsevier España, S.L.U. All rights reserved.

Cardiac structure and function predicts functional decline in the oldest old.

PubMed

Leibowitz, David; Jacobs, Jeremy M; Lande-Stessman, Irit; Gilon, Dan; Stessman, Jochanan

2018-02-01

Background This study examined the association between cardiac structure and function and the deterioration in activities of daily living (ADLs) in an age-homogenous, community-dwelling population of patients born in 1920-1921 over a five-year follow-up period. Design Longitudinal cohort study. Methods Patients were recruited from the Jerusalem Longitudinal Cohort Study, which has followed an age-homogenous cohort of Jerusalem residents born in 1920-1921. Patients underwent home echocardiography and were followed up for five years. Dependence was defined as needing assistance with one or more basic ADL. Standard echocardiographic assessment of cardiac structure and function, including systolic and diastolic function, was performed. Reassessment of ADLs was performed at the five-year follow-up. Results A total of 459 patients were included in the study. Of these, 362 (79%) showed a deterioration in at least one ADL at follow-up. Patients with functional deterioration had a significantly higher left ventricular mass index and left atrial volume with a lower ejection fraction. There was no significant difference between the diastolic parameters the groups in examined. When the data were examined categorically, a significantly larger percentage of patients with functional decline had an abnormal left ventricular ejection fraction and left ventricular hypertrophy. The association between left ventricular mass index and functional decline remained significant in all multivariate models. Conclusions In this cohort of the oldest old, an elevated left ventricular mass index, higher left atrial volumes and systolic, but not diastolic dysfunction, were predictive of functional disability.

Evaluation of effect of atorvastatin on left ventricular systolic function in rats with myocardial infarction via 2D-STI technique.

PubMed

Hua, Yan; Xie, Manying; Yin, Jiabao; Wang, Yu; Gan, Ling; Sang, Ming; Sun, Xiaodong; Li, Mingyang; Liu, Shanjun; Xu, Jinzhi

2018-05-01

This report aims to evaluate the effect of atorvastatin (Ator) on left ventricular systolic function in myocardial infarction (MI) rats. Forty healthy adult Sprague-Dawley rats were randomly divided into four groups: Ator group, MI group, sham-operation group and normal group. The left anterior descending coronary arteries were ligated to establish the MI model; after modeling, the Ator group was treated with Ator for 4 consecutive weeks. The echocardiographic detection was performed; the left ventricular myocardial systolic peak velocities, strain and strain rates were analyzed using the 2D-STI technique. After 4 weeks, myocardial tissues were taken from all rats and received the pathological examination. Left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) in Ator group and MI group were increased after operation, but left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were decreased; myocardial function were decreased significantly (p<0.05). After Ator treatment, myocardial function at the 3rd and 4th week after operation increased significantly (p<0.05). After Ator treatment, LVEDD and LVESD decreased while LVEF and LVFS increased in Ator group at the 3rd and 4th week after operation compared with MI group (p<0.05). At the 4th week after operation, LVEDD and LVESD in Ator group were decreased compared with those at the 1st and 2nd week after operation, but LVEF and LVFS were increased compared with those at the 1st, 2nd and 3rd week after operation (p<0.05). Pathological examination showed that necrosis and fibrosis of myocardial cells and inflammatory reaction were obvious in MI group. The inflammatory reaction of myocardial cells and myocardial fibrosis were lighter in Ator group. Ator can effectively improve the left ventricular systolic function in MI rats, which could be related to the reduction of response to inflammation and fibrosis.

Interplay between arterial stiffness and diastolic function: a marker of ventricular-vascular coupling.

PubMed

Zito, Concetta; Mohammed, Moemen; Todaro, Maria Chiara; Khandheria, Bijoy K; Cusmà-Piccione, Maurizio; Oreto, Giuseppe; Pugliatti, Pietro; Abusalima, Mohamed; Antonini-Canterin, Francesco; Vriz, Olga; Carerj, Scipione

2014-11-01

We evaluated the interplay between left ventricular diastolic function and large-artery stiffness in asymptomatic patients at increased risk of heart failure and no structural heart disease (Stage A). We divided 127 consecutive patients (mean age 49 ± 17 years) with risk factors for heart failure who were referred to our laboratory to rule out structural heart disease into two groups according to presence (Group 1, n = 35) or absence (Group 2, n = 92) of grade I left ventricular diastolic dysfunction. Doppler imaging with high-resolution echo-tracking software was used to measure intima-media thickness (IMT) and stiffness of carotid arteries. Group 1 had significantly higher mean age, blood pressure, left ventricular mass index, carotid IMT and arterial stiffness than Group 2 (P < 0.05). Overall, carotid stiffness indices (β-stiffness index, augmentation index and elastic modulus) and 'one-point' pulse wave velocity each showed inverse correlation with E-wave velocity, E' velocity and E/A ratio, and direct correlation with A-wave velocity, E-wave deceleration time and E/E' ratio (P < 0.05). Arterial compliance showed negative correlations with the echocardiographic indices of left ventricular diastolic function (P < 0.05). On logistic regression analysis, age, hypertension, SBP, pulse pressure, left ventricular mass index, carotid IMT and stiffness parameters were associated with grade I left ventricular diastolic dysfunction (P < 0.05 for each). However, on multivariate logistic analysis, only 'one-point' pulse wave velocity and age were independent predictors (P = 0.038 and P = 0.016, respectively). An independent association between grade I left ventricular diastolic dysfunction and increased arterial stiffness is demonstrated at the earliest stage of heart failure. Hence, assessment of vascular function, beyond cardiac function, should be included in a comprehensive clinical evaluation of these patients.

How best to assess right ventricular function by echocardiography*

PubMed Central

DiLorenzo, Michael P.; Bhatt, Shivani M.; Mercer-Rosa, Laura

2016-01-01

Right ventricular function is a crucial determinant of long-term outcomes of children with heart disease. Quantification of right ventricular systolic and diastolic performance by echocardiography is of paramount importance, given the prevalence of children with heart disease, particularly those with involvement of the right heart, such as single or systemic right ventricles, tetralogy of Fallot, and pulmonary arterial hypertension. Identification of poor right ventricular performance can provide an opportunity to intervene. In this review, we will go through the different systolic and diastolic indices, as well as their application in practice. Quantification of right ventricular function is possible and should be routinely performed using a combination of different measures, taking into account each disease state. Quantification is extremely useful for individual patient follow-up. Laboratories should continue to strive to optimise reproducibility through quality improvement and quality assurance efforts in addition to investing in technology and training for new, promising techniques, such as three-dimensional echocardiography. PMID:26675593

Subclinical changes in MRI-determined right ventricular volumes and function in subjects with prediabetes and diabetes.

PubMed

Patscheider, Hannah; Lorbeer, Roberto; Auweter, Sigrid; Schafnitzel, Anina; Bayerl, Christian; Curta, Adrian; Rathmann, Wolfgang; Heier, Margit; Meisinger, Christa; Peters, Annette; Bamberg, Fabian; Hetterich, Holger

2018-07-01

The aim of this study was to assess subclinical changes in right ventricular volumes and function in subjects with prediabetes and diabetes and controls without a history of cardiovascular disease. Data from 400 participants in the KORA FF4 study without self-reported cardiovascular disease who underwent 3-T whole-body MRI were obtained. The right ventricle was evaluated using the short axis and a four-chamber view. Diabetes was defined according to WHO criteria. Associations between glucose tolerance and right ventricular parameters were assessed using multivariable adjusted linear regression models. Data from 337 participants were available for analysis. Of these, 43 (13%) had diabetes, 87 (26%) had prediabetes, and 207 (61%) were normoglycaemic controls. There was a stepwise decrease in right ventricular volumes in men with prediabetes and diabetes in comparison with controls, including right ventricular end-diastolic volume (β = -20.4 and β = -25.6, respectively; p ≤ 0.005), right ventricular end-systolic volume (β = -12.3 and β = -12.7, respectively; p ≤ 0.037) and right ventricular stroke volume (β = -8.1 and β = -13.1, respectively, p ≤ 0.016). We did not observe any association between prediabetes or diabetes and right ventricular volumes in women or between prediabetes or diabetes and right ventricular ejection fraction in men and women. This study points towards early subclinical changes in right ventricular volumes in men with diabetes and prediabetes. • MRI was used to detect subclinical changes in right ventricular parameters. • Diabetes mellitus is associated with right ventricular dysfunction. • Impairment of right ventricular volumes seems to occur predominantly in men.

Sedentary Screen Time and Left Ventricular Structure and Function: the CARDIA Study

PubMed Central

Gibbs, Bethany Barone; Reis, Jared P.; Schelbert, Erik B.; Craft, Lynette L.; Sidney, Steve; Lima, Joao; Lewis, Cora E.

2013-01-01

Sedentary screen time (watching TV or using a computer) predicts cardiovascular outcomes independently from moderate and vigorous physical activity and could impact left ventricular structure and function through the adverse consequences of sedentary behavior. Purpose To determine whether sedentary screen time is associated with measures of left ventricular structure and function. Methods The Coronary Artery Risk Development in Young Adults (CARDIA) Study measured screen time by questionnaire and left ventricular structure and function by echocardiography in 2,854 black and white participants, aged 43–55 years, in 2010–2011. Generalized linear models evaluated cross-sectional trends for echocardiography measures across higher categories of screen time and adjusting for demographics, smoking, alcohol, and physical activity. Further models adjusted for potential intermediate factors (blood pressure, antihypertensive medication use, diabetes, and body mass index (BMI). Results The relationship between screen time and left ventricular mass(LVM) differed in blacks vs. whites. Among whites, higher screen time was associated with larger LVM (P<0.001), after adjustment for height, demographics, and lifestyle variables. Associations between screen time and LVM persisted when adjusting for blood pressure, antihypertensive medication use, and diabetes (P=0.008) but not with additional adjustment for BMI (P=0.503). Similar relationships were observed for screen time with LVM indexed to height2.7, relative wall thickness, and mass-to-volume ratio. Screen time was not associated with left ventricular structure among blacks or left ventricular function in either race group. Conclusions Sedentary screen time is associated with greater LVM in white adults and this relationship was largely explained by higher overall adiposity. The lack of association in blacks supports a potential qualitative difference in the cardiovascular consequences of sedentary screen-based behavior. PMID:23863618

Mechanical Circulatory Support of the Critically Ill Child Awaiting Heart Transplantation

PubMed Central

Gazit, Avihu Z; Gandhi, Sanjiv K; C Canter, Charles

2010-01-01

The majority of children awaiting heart transplantation require inotropic support, mechanical ventilation, and/or extracorporeal membrane oxygenation (ECMO) support. Unfortunately, due to the limited pool of organs, many of these children do not survive to transplant. Mechanical circulatory support of the failing heart in pediatrics is a new and rapidly developing field world-wide. It is utilized in children with acute congestive heart failure associated with congenital heart disease, cardiomyopathy, and myocarditis, both as a bridge to transplantation and as a bridge to myocardial recovery. The current arsenal of mechanical assist devices available for children is limited to ECMO, intra-aortic balloon counterpulsation, centrifugal pump ventricular assist devices, the DeBakey ventricular assist device Child; the Thoratec ventricular assist device; and the Berlin Heart. In the spring of 2004, five contracts were awarded by the National Heart, Lung and Blood Institute to support preclinical development for a range of pediatric ventricular assist devices and similar circulatory support systems. The support of early development efforts provided by this program is expected to yield several devices that will be ready for clinical trials within the next few years. Our work reviews the current international experience with mechanical circulatory support in children and summarizes our own experience since 2005 with the Berlin Heart, comparing the indications for use, length of support, and outcome between these modalities. PMID:21286278

Coronary oscillatory flow amplitude is more affected by perfusion pressure than ventricular pressure.

PubMed

Krams, R; Sipkema, P; Westerhof, N

1990-06-01

In this study on the isolated, maximally vasodilated, blood-perfused cat heart we investigated the relation between left ventricular developed pressure (delta Piv) and coronary oscillatory flow amplitude (diastolic minus systolic flow, delta F) at different levels of constant perfusion pressure (Pp). We hypothesized that the effect of cardiac contraction on the phasic flow results from the changing elastic properties of cardiac muscle. The coronary vessel compartment can, as can the left ventricular lumen compartment, be described by a time-varying elastance. This concept predicts that the effect of left ventricular pressure on delta F is small, whereas the effect of Pp is considerable. Both the waterfall model and the intramyocardial pump model predict the inverse. The relation between delta Piv and delta F at a Pp of 10 kPa is delta F = (4.71 +/- 3.08).delta Piv + 337 +/- 75 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 7); the relation between (constant levels of) Pp and delta F at a constant delta Piv of 10 kPa is delta F = 51.Pp + 211 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 6). The differences in slope are best predicted by the time-varying elastance concept.

Sensitivity of Rabbit Ventricular Action Potential and Ca2+ Dynamics to Small Variations in Membrane Currents and Ion Diffusion Coefficients

PubMed Central

Lo, Yuan Hung; Peachey, Tom; Abramson, David; McCulloch, Andrew

2013-01-01

Little is known about how small variations in ionic currents and Ca2+ and Na+ diffusion coefficients impact action potential and Ca2+ dynamics in rabbit ventricular myocytes. We applied sensitivity analysis to quantify the sensitivity of Shannon et al. model (Biophys. J., 2004) to 5%–10% changes in currents conductance, channels distribution, and ion diffusion in rabbit ventricular cells. We found that action potential duration and Ca2+ peaks are highly sensitive to 10% increase in L-type Ca2+ current; moderately influenced by 10% increase in Na+-Ca2+ exchanger, Na+-K+ pump, rapid delayed and slow transient outward K+ currents, and Cl− background current; insensitive to 10% increases in all other ionic currents and sarcoplasmic reticulum Ca2+ fluxes. Cell electrical activity is strongly affected by 5% shift of L-type Ca2+ channels and Na+-Ca2+ exchanger in between junctional and submembrane spaces while Ca2+-activated Cl−-channel redistribution has the modest effect. Small changes in submembrane and cytosolic diffusion coefficients for Ca2+, but not in Na+ transfer, may alter notably myocyte contraction. Our studies highlight the need for more precise measurements and further extending and testing of the Shannon et al. model. Our results demonstrate usefulness of sensitivity analysis to identify specific knowledge gaps and controversies related to ventricular cell electrophysiology and Ca2+ signaling. PMID:24222910

[Assessment of myocardial perfusion and left ventricular function with 99mTc-PPN 1011].

PubMed

Kumita, S; Mizumura, S; Oishi, T; Kumazaki, T; Sano, J; Yamazaki, Y; Munakata, K

1993-04-01

First-pass radionuclide angiography (FPRNA) was performed with the new myocardial perfusion agent 99mTc-1,2,bis[bis(2-ethoxyethyl)phosphino] ethane (99mTc-PPN 1011) on stress and at rest. One hour after that, myocardial perfusion was counted by 99mTc-PPN 1011 SPECT. Left ventricular ejection fraction (LVEF) obtained by FPRNA correlated with that by multigated image with 99mTc-HSAD (r = 0.94, n = 11). The reduction of left ventricular function under the exercise (delta LVEF) and the increase of severity score (delta Severity score) have a good relation (r = 0.88) in 7 patients with prior myocardial infarction. Thus 99mTc-PPN 1011 appears to be an ideal radiopharmaceutical for evaluation of ventricular function and myocardial perfusion.

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison.

PubMed

Avery, Ryan; Day, Kevin; Jokerst, Clinton; Kazui, Toshinobu; Krupinski, Elizabeth; Khalpey, Zain

2017-10-10

Advanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function. A retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed. The 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 - 40%). Mean LVEF using MUGA was 22.6% (12 - 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 - 43%), and the mean RVEF calculated by FPRNA was 32.6% (9 - 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 - 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 - 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 - 0.72) and for FAC of 0.64 (95% of 0.21 - 1.00). Heart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

Ca2+ handling remodeling and STIM1L/Orai1/TRPC1/TRPC4 upregulation in monocrotaline-induced right ventricular hypertrophy.

PubMed

Jessica, Sabourin; Angèle, Boet; Catherine, Rucker-Martin; Mélanie, Lambert; Ana-Maria, Gomez; Jean-Pierre, Benitah; Frédéric, Perros; Marc, Humbert; Fabrice, Antigny

2018-05-01

Right ventricular (RV) function is the most important prognostic factor for pulmonary arterial hypertension (PAH) patients. The progressive increase of pulmonary vascular resistance induces RV hypertrophy (RVH) and at term RV failure (RVF). However, the molecular mechanisms of RVH and RVF remain understudied. In this study, we gained insights into cytosolic Ca 2+ signaling remodeling in ventricular cardiomyocytes during the pathogenesis of severe pulmonary hypertension (PH) induced in rats by monocrotaline (MCT) exposure, and we further identified molecular candidates responsible for this Ca 2+ remodeling. After PH induction, hypertrophied RV myocytes presented longer action potential duration, higher and faster [Ca 2+ ] i transients and increased sarcoplasmic reticulum (SR) Ca 2+ content, whereas no changes in these parameters were detected in left ventricular (LV) myocytes. These modifications were associated with increased P-Ser 16 -phospholamban pentamer expression without altering SERCA2a (Sarco/Endoplasmic Reticulum Ca 2+ -ATPase) pump abundance. Moreover, after PH induction, Ca 2+ sparks frequency were higher in hypertrophied RV cells, while total RyR2 (Ryanodine Receptor) expression and phosphorylation were unaffected. Together with cellular hypertrophy, the T-tubules network was disorganized. Hypertrophied RV cardiomyocytes from MCT-exposed rats showed decreased expression of classical STIM1 (Stromal Interaction molecule) associated with increased expression of muscle-specific STIM1 Long isoform, glycosylated-Orai1 channel form, and TRPC1 and TRPC4 channels, which was correlated with an enhanced Ca 2+ -release-activated Ca 2+ (CRAC)-like current. Pharmacological inhibition of TRPCs/Orai1 channels in hypertrophied RV cardiomyocytes normalized [Ca 2+ ] i transients amplitude, the SR Ca 2+ content and cell contractility to control levels. Finally, we showed that most of these changes did not appear in LV cardiomyocytes. These new findings demonstrate RV-specific cellular Ca 2+ cycling remodeling in PH rats with maladaptive RVH and that the STIM1L/Orai1/TRPC1/C4-dependent Ca 2+ current participates in this Ca 2+ remodeling in RVH secondary to PH. Copyright © 2018 Elsevier Ltd. All rights reserved.

Left ventricular dimensions, systolic functions, and mass in term neonates with symmetric and asymmetric intrauterine growth restriction.

PubMed

Cinar, Bahar; Sert, Ahmet; Gokmen, Zeynel; Aypar, Ebru; Aslan, Eyup; Odabas, Dursun

2015-02-01

Previous studies have demonstrated structural changes in the heart and cardiac dysfunction in foetuses with intrauterine growth restriction. There are no available data that evaluated left ventricular dimensions and mass in neonates with symmetric and asymmetric intrauterine growth restriction. Therefore, we aimed to evaluate left ventricular dimensions, systolic functions, and mass in neonates with symmetric and asymmetric intrauterine growth restriction. We also assessed associated maternal risk factors, and compared results with healthy appropriate for gestational age neonates. In all, 62 asymmetric intrauterine growth restriction neonates, 39 symmetric intrauterine growth restriction neonates, and 50 healthy appropriate for gestational age neonates were evaluated by transthoracic echocardiography. The asymmetric intrauterine growth restriction group had significantly lower left ventricular end-systolic and end-diastolic diameters and posterior wall diameter in systole and diastole than the control group. The symmetric intrauterine growth restriction group had significantly lower left ventricular end-diastolic diameter than the control group. All left ventricular dimensions were lower in the asymmetric intrauterine growth restriction neonates compared with symmetric intrauterine growth restriction neonates (p>0.05), but not statistically significant except left ventricular posterior wall diameter in diastole (3.08±0.83 mm versus 3.54 ±0.72 mm) (p<0.05). Both symmetric and asymmetric intrauterine growth restriction groups had significantly lower relative posterior wall thickness (0.54±0.19 versus 0.48±0.13 versus 0.8±0.12), left ventricular mass (9.8±4.3 g versus 8.9±3.4 g versus 22.2±5.7 g), and left ventricular mass index (63.6±29.1 g/m2 versus 54.5±24.4 g/m2 versus 109±28.8 g/m2) when compared with the control group. Our study has demonstrated that although neonates with both symmetric and asymmetric intrauterine growth restriction had lower left ventricular dimensions, relative posterior wall thickness, left ventricular mass, and mass index when compared with appropriate for gestational age neonates, left ventricular systolic functions were found to be preserved. In our study, low socio-economic level, short maternal stature, and low maternal weight were found to be risk factors to develop intrauterine growth restriction. To our knowledge, our study is the first to evaluate left ventricular dimensions, wall thicknesses, mass, and systolic functions in neonates with intrauterine growth restriction and compare results with respect to asymmetric or symmetric subgroups.

Rupture of extra-corporeal circuit tubing during cardiopulmonary bypass.

PubMed

Sai Krishna, Cheemalapati; Naresh Kumar, Palli Venkata; Satpathy, Soumya Kanta; Ram Mohan, Kanteti; Ramesh Babu, Vedangi

2008-03-01

Roller pumps are widely used for cardiopulmonary bypass in developing nations by virtue of proven safety during several years of institutional use and cost effectiveness. However, careful adjustment of roller occlusion is needed because they are known to cause spallation, tubing wear, and the occasional incident of rupture of tubing in the extracorporeal circuit. Rupture of polyvinylchloride tubing in the pump raceway during repair of a ventricular septal defect in a 4-year-old child is discussed. The event was managed by exclusion and replacement of the defective tubing during a short period of arrest. Use of an inappropriate boot pump and failure to detect its inclusion in the bypass circuit was a significant departure from protocol. However, because occlusion settings and duration of perfusion were within acceptable limits, a manufacturing flaw could also have contributed to tubing failure, and the event may or may not have been averted by the use of larger tubing. In conclusion, this incident reiterates the need for adherence to established protocol during assembly of the pump and draws attention to the fact that tubing integrity is not a guarantee and vigilance is warranted to handle its failure.

Rupture of Extra-Corporeal Circuit Tubing During Cardiopulmonary Bypass

PubMed Central

Krishna, Cheemalapati Sai; Kumar, Palli Venkata Naresh; Satpathy, Soumya Kanta; Mohan, Kanteti Ram; Babu, Vedangi Ramesh

2008-01-01

Abstract: Roller pumps are widely used for cardiopulmonary bypass in developing nations by virtue of proven safety during several years of institutional use and cost effectiveness. However, careful adjustment of roller occlusion is needed because they are known to cause spallation, tubing wear, and the occasional incident of rupture of tubing in the extracorporeal circuit. Rupture of polyvinylchloride tubing in the pump raceway during repair of a ventricular septal defect in a 4-year-old child is discussed. The event was managed by exclusion and replacement of the defective tubing during a short period of arrest. Use of an inappropriate boot pump and failure to detect its inclusion in the bypass circuit was a significant departure from protocol. However, because occlusion settings and duration of perfusion were within acceptable limits, a manufacturing flaw could also have contributed to tubing failure, and the event may or may not have been averted by the use of larger tubing. In conclusion, this incident reiterates the need for adherence to established protocol during assembly of the pump and draws attention to the fact that tubing integrity is not a guarantee and vigilance is warranted to handle its failure. PMID:18389670

The Change of Left Ventricular Function in Rats with Subclinical Hypothyroid and the Effects of Thyroxine Replacement.

PubMed

Chen, Xuedi; Gao, Cuixia; Gong, Ningning; Wang, Yu; Tian, Limin

2018-01-01

The main purpose of this study was to explore the relationships between serca2a, Ryr2, adipokines, and the left ventricular function in the subclinical hypothyroidism with different TSH levels and to determine the impact of L-T4 treatment on these indexes. Sixty-five male Wistar rats were randomly divided into five groups: control group; sHT A, B, and C group; and sHT + T4 group. The sHT rats were induced by methimazole (MMI), and the sHT + T4 rats were administered with L-T4 treatment after 8 weeks of MMI administration. Serum TT4, TSH, APN, chemerin, and TNF- α were detected by radioimmunoassay kits and ELISA kits; left ventricular function was measured by PowerLab system via subclavian artery catheter. The expression of Serca2a, Ryr2, APN, chemerin, and TNF- α were detected by RT-PCR, Western blot, and immunohistochemistry. The sHT groups had significantly higher TSH, chemerin, and TNF- α and lower Serca2a, Ryr2, and APN. The left ventricular pressure and heart rate in sHT groups were significantly lower in control and sHT + T4 group. Histopathological examination revealed the pathological changes in the sHT rats' heart. L-T4 administration reduced TSH level and improved left ventricular function. TSH can impair left ventricular function by regulating several factors, and L-T4 treatment ameliorates it in sHT rats.

Electromechanical heterogeneity in the heart : A key to long QT syndrome?

PubMed

Dressler, F F; Brado, J; Odening, K E

2018-03-01

In the healthy heart, physiological heterogeneities in structure and in electrical and mechanical activity are crucial for normal, efficient excitation and pumping. Alterations of heterogeneity have been linked to arrhythmogenesis in various cardiac disorders such as long QT syndrome (LQTS). This inherited arrhythmia disorder is caused by mutations in different ion channel genes and is characterized by (heterogeneously) prolonged cardiac repolarization and increased risk for ventricular tachycardia, syncope and sudden cardiac death. Cardiac electrical and mechanical function are not independent of each other but interact in a bidirectional manner by electromechanical and mechano-electrical coupling. Therefore, changes in either process will affect the other. Recent experimental and clinical evidence suggests that LQTS, which is primarily considered an "electrical" disorder, also exhibits features of disturbed mechanical function and heterogeneity, which in turn appears to correlate with the risk of arrhythmia in the individual patient. In this review, we give a short overview of the current knowledge about physiological and pathological, long QT-related electrical and mechanical heterogeneity in the heart. Also, their respective roles for future risk prediction approaches in LQTS are discussed.

A Fully Magnetically Levitated Circulatory Pump for Advanced Heart Failure.

PubMed

Mehra, Mandeep R; Naka, Yoshifumi; Uriel, Nir; Goldstein, Daniel J; Cleveland, Joseph C; Colombo, Paolo C; Walsh, Mary N; Milano, Carmelo A; Patel, Chetan B; Jorde, Ulrich P; Pagani, Francis D; Aaronson, Keith D; Dean, David A; McCants, Kelly; Itoh, Akinobu; Ewald, Gregory A; Horstmanshof, Douglas; Long, James W; Salerno, Christopher

2017-02-02

Continuous-flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous-flow pump that was engineered to avert thrombosis. We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous-flow pump or a commercially available axial continuous-flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, -10 percentage points). Of 294 patients, 152 were assigned to the centrifugal-flow pump group and 142 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal-flow pump group and in 109 (76.8%) in the axial-flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, -2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two-tailed P=0.04 for superiority]). There were no significant between-group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal-flow pump group and in 14 patients (10.1%) in the axial-flow pump group. Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal-flow pump was associated with better outcomes at 6 months than was implantation of an axial-flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Arterial Ventricular Uncoupling with Age and Disease and Recoupling with Exercise

PubMed Central

Chantler, Paul D

2017-01-01

The deterioration in arterial and cardiac function with aging impairs arterial ventricular coupling, an important determinant of cardiovascular performance. However, exercise training improves arterial ventricular coupling especially during exercise during the age and disease process. This review examines the concept of arterial-ventricular coupling, and how age, and disease uncouples but exercise training recouples the heart and arterial system. PMID:28072585

Experimental myocardial infarction

PubMed Central

Kumar, Raj; Joison, Julio; Gilmour, David P.; Molokhia, Farouk A.; Pegg, C. A. S.; Hood, William B.

1971-01-01

The hemodynamic effects of tachycardia induced by atrial pacing were investigated in left ventricular failure of acute and healing experimental myocardial infarction in 20 intact, conscious dogs. Myocardial infarction was produced by gradual inflation of a balloon cuff device implanted around the left anterior descending coronary artery 10-15 days prior to the study. 1 hr after acute myocardial infarction, atrial pacing at a rate of 180 beats/min decreased left ventricular end-diastolic pressure from 19 to 8 mm Hg and left atrial pressure from 17 to 12 mm Hg, without change in cardiac output. In the healing phase of myocardial infarction 1 wk later, atrial pacing decreased left ventricular end-diastolic pressure from 17 to 9 mm Hg and increased the cardiac output by 37%. This was accompanied by evidence of peripheral vasodilation. In two dogs with healing anterior wall myocardial infarction, left ventricular failure was enhanced by partial occlusion of the circumflex coronary artery. Both the dogs developed pulmonary edema. Pacing improved left ventricular performance and relieved pulmonary edema in both animals. In six animals propranolol was given after acute infarction, and left ventricular function deteriorated further. However the pacing-induced augmentation of cardiac function was unaltered and, hence, is not mediated by sympathetics. The results show that the spontaneous heart rate in left ventricular failure of experimental canine myocardial infarction may be less than optimal and that maximal cardiac function may be achieved at higher heart rates. Images PMID:4395910

Renal denervation in male rats with heart failure improves ventricular sympathetic nerve innervation and function

PubMed Central

Pinkham, Maximilian I.; Loftus, Michael T.; Amirapu, Satya; Guild, Sarah-Jane; Quill, Gina; Woodward, William R.; Habecker, Beth A.

2017-01-01

Heart failure is characterized by the loss of sympathetic innervation to the ventricles, contributing to impaired cardiac function and arrhythmogenesis. We hypothesized that renal denervation (RDx) would reverse this loss. Male Wistar rats underwent myocardial infarction (MI) or sham surgery and progressed into heart failure for 4 wk before receiving bilateral RDx or sham RDx. After additional 3 wk, left ventricular (LV) function was assessed, and ventricular sympathetic nerve fiber density was determined via histology. Post-MI heart failure rats displayed significant reductions in ventricular sympathetic innervation and tissue norepinephrine content (nerve fiber density in the LV of MI+sham RDx hearts was 0.31 ± 0.05% vs. 1.00 ± 0.10% in sham MI+sham RDx group, P < 0.05), and RDx significantly increased ventricular sympathetic innervation (0.76 ± 0.14%, P < 0.05) and tissue norepinephrine content. MI was associated with an increase in fibrosis of the noninfarcted ventricular myocardium, which was attenuated by RDx. RDx improved LV ejection fraction and end-systolic and -diastolic areas when compared with pre-RDx levels. This is the first study to show an interaction between renal nerve activity and cardiac sympathetic nerve innervation in heart failure. Our findings show denervating the renal nerves improves cardiac sympathetic innervation and function in the post-MI failing heart. PMID:28052866

Newly developed ventricular assist device with linear oscillatory actuator.

PubMed

Fukunaga, Kazuyoshi; Funakubo, Akio; Fukui, Yasuhiro

2003-01-01

The goal of this study was to develop a new direct electromagnetic left ventricular assist device (DEM-LVAD) with a linear oscillatory actuator (LOA). The DEM-LVAD is a pulsatile pump with a pusher plate. The pusher plate is driven directly by the mover of the LOA. The LOA provides reciprocating motion without using any movement converter such as a roller screw or a hydraulic system. It consists of a stator with a single winding excitation coil and a mover with two permanent magnets. The simple structure of the LOA is based on fewer parts to bring about high reliability and smaller size. The mover moves back and forth when forward and backward electric current is supplied to the excitation coil. The pump housings have been designed using three-dimensional computer aided design software and fabricated with the aid of computer aided manufacturing technology. Monostrut valves (Bjork-Shiley #21) were used for the prototype. The DEM-LVAD dimension is 96 mm in diameter and 50 mm thick with a mass of 0.62 kg and a volume of 280 ml. An in vitro test (afterload 100 mm Hg; preload 10 mm Hg; input power 10 W) demonstrated more than 6 L/minute maximum output and 15% maximum efficiency at 130 beats per minute (bpm). Dynamic stroke volume ranged between 40 and 60 ml. The feasibility of the DEM-LVAD was confirmed.

Noninvasive blood-flow meter using a curved cannula with zero compensation for an axial flow blood pump.

PubMed

Kosaka, Ryo; Fukuda, Kyohei; Nishida, Masahiro; Maruyama, Osamu; Yamane, Takashi

2013-01-01

In order to monitor the condition of a patient using a left ventricular assist system (LVAS), blood flow should be measured. However, the reliable determination of blood-flow rate has not been established. The purpose of the present study is to develop a noninvasive blood-flow meter using a curved cannula with zero compensation for an axial flow blood pump. The flow meter uses the centrifugal force generated by the flow rate in the curved cannula. Two strain gauges served as sensors. The first gauges were attached to the curved area to measure static pressure and centrifugal force, and the second gauges were attached to straight area to measure static pressure. The flow rate was determined by the differences in output from the two gauges. The zero compensation was constructed based on the consideration that the flow rate could be estimated during the initial driving condition and the ventricular suction condition without using the flow meter. A mock circulation loop was constructed in order to evaluate the measurement performance of the developed flow meter with zero compensation. As a result, the zero compensation worked effectively for the initial calibration and the zero-drift of the measured flow rate. We confirmed that the developed flow meter using a curved cannula with zero compensation was able to accurately measure the flow rate continuously and noninvasively.

Serial changes in anatomy and ventricular function on dual-source cardiac computed tomography after the Norwood procedure for hypoplastic left heart syndrome.

PubMed

Goo, Hyun Woo

2017-12-01

Accurate evaluation of anatomy and ventricular function after the Norwood procedure in hypoplastic left heart syndrome is important for treatment planning and prognostication, but echocardiography and cardiac MRI have limitations. To assess serial changes in anatomy and ventricular function on dual-source cardiac CT after the Norwood procedure for hypoplastic left heart syndrome. In 14 consecutive patients with hypoplastic left heart syndrome, end-systolic and end-diastolic phase cardiac dual-source CT was performed before and early (average: 1 month) after the Norwood procedure, and repeated late (median: 4.5 months) after the Norwood procedure in six patients. Ventricular functional parameters and indexed morphological measurements including pulmonary artery size, right ventricular free wall thickness, and ascending aorta size on cardiac CT were compared between different time points. Moreover, morphological features including ventricular septal defect, endocardial fibroelastosis and coronary ventricular communication were evaluated on cardiac CT. Right ventricular function and volumes remained unchanged (indexed end-systolic and end-diastolic volumes: 38.9±14.0 vs. 41.1±21.5 ml/m 2 , P=0.7 and 99.5±30.5 vs. 105.1±33.0 ml/m 2 , P=0.6; ejection fraction: 60.1±7.3 vs. 63.8±7.0%, P=0.1, and indexed stroke volume: 60.7±18.0 vs. 64.0±15.6 ml/m 2 , P=0.5) early after the Norwood procedure, but function was decreased (ejection fraction: 64.2±2.6 vs. 58.1±7.1%, P=0.01) and volume was increased (indexed end-systolic and end-diastolic volumes: 39.2±14.9 vs. 68.9±20.6 ml/m 2 , P<0.003 and 107.8±36.5 vs. 162.9±36.2 ml/m 2 , P<0.006, and indexed stroke volume: 68.6±21.7 vs. 94.0±21.3 ml/m 2 , P=0.02) later. Branch pulmonary artery size showed a gradual decrease without asymmetry after the Norwood procedure. Right and left pulmonary artery stenoses were identified in 21.4% (3/14) of the patients. Indexed right ventricular free wall thickness showed a significant increase early after the Norwood procedure (25.5±3.5 vs. 34.8±5.1 mm/m 2 , P=0.01) and then a significant decrease late after the Norwood procedure (34.8±5.1 vs. 27.2±4.2 mm/m 2 , P<0.0001). The hypoplastic ascending aorta smaller than 2 mm in diameter was identified in 21.4% (3/14) of the patients. Ventricular septal defect (n=3), endocardial fibroelastosis (n=2) and coronary ventricular communication (n=1) were detected on cardiac CT. Cardiac CT can be used to assess serial changes in anatomy and ventricular function after the Norwood procedure in patients with hypoplastic left heart syndrome.

Development of real-time and quantitative monitoring of thrombus formation in an extracorporeal centrifugal blood pump

NASA Astrophysics Data System (ADS)

Sakota, Daisuke; Fujiwara, Tatsuki; Ohuchi, Katsuhiro; Kuwana, Katsuyuki; Yamazaki, Hiroyuki; Kosaka, Ryo; Maruyama, Osamu

2018-02-01

We developed an optical detector of thrombus formed on the pivot bearing of an extracorporeal centrifugal blood pump (MERA HCF-MP23; Senko Medical Instrument Mfg. Co., Ltd., Tokyo, Japan) which is frequently used for long-term extracorporeal circulation support to bridge to an implantable artificial heart, which in turn is used for bridge to heart transplantation in Japan. In this study, we investigated the quantitative performance of the thrombus formation in acute animal experiments. A total of three experiments of extracorporeal left ventricular assist using Japanese specific pathogen-free pigs were conducted. The optical fibers were set in the pump driver unit. The incident light at nearinfrared wavelength aiming at the pivot bearing and the resulting scattered light were guided to respective fibers. The detected signal was analyzed to obtain thrombus formation level (TFL) calculated by a specially developed software. When the increase in TFL was confirmed, the pump was exchanged and the extracorporeal circulation was restarted. The number of pump exchanges were four times at each experiment so a total of twelve pumps were evaluated. 3-dimentional data surrounding the pivot bearing and the adhered thrombus was captured by a 3-dimantional surface measurement system to calculate the thrombus surface area (TSA) formed on the pivot bearing. As a result, the correlation coefficient between TFL and TSA was 0.878. The accuracy of TSA estimated by the optical detector was 3.6+/-2.3 mm2. This was small enough to not have the pump exchanged in clinical judgement. The developed detector would be useful for optimal anti-coagulation management.

Choroidal microcirculation in patients with rotary cardiac assist device.

PubMed

Polska, Elzbieta; Schima, Heinrich; Wieselthaler, Georg; Schmetterer, Leopold

2007-06-01

In recent years, fully implanted rotary blood pumps have been used for long-term cardiac assist in patients with end-stage heart failure. With these pumps, the pulsatility of arterial blood flow and arterial pressure pulse is considerably reduced. Effects on end-organ perfusion, particularly microcirculation, have been assessed. The ocular choroid offers a unique opportunity to study the pulsatile component of blood flow by measurement of fundus pulsation amplitude (FPA) as well as the microcirculation by laser Doppler flowmetry. Both techniques were applied in three male patients with rotary pumps (MicroMed DeBakey VAD), in whom pump velocity was adjusted to four levels of flow between individual minimal need and maximal support. In addition, blood flow velocities in the ophthalmic artery (peak, end-diastolic and mean flow velocity--PSV, EDV and MFV, respectively) were measured using color Doppler imaging. Systolic blood pressure increased by 6 to 22 mm Hg with increasing support. At maximal support FPA was reduced by -60% to -52% as compared with minimal pump support. Blood flow in the choroidal microvasculature, however, did not show relevant changes. A reduction in PSV (-31%, range -47% to -21%) and a pronounced rise in EDV (+93%, range +28% to +147%) was observed, whereas MFV was independent of pump flow. Our data indicate that mean choroidal blood flow is maintained when pump support is varied within therapeutic values, whereas the ratio of pulsatile to non-pulsatile choroidal flow changes. This study shows that, in patients with ventricular assist devices, a normal perfusion rate in the ocular microcirculation is maintained over a wide range of support conditions.

Quantitative computed tomography of pulmonary emphysema and ventricular function in chronic obstructive pulmonary disease patients with pulmonary hypertension.

PubMed

Huang, Yu-Sen; Hsu, Hsao-Hsun; Chen, Jo-Yu; Tai, Mei-Hwa; Jaw, Fu-Shan; Chang, Yeun-Chung

2014-01-01

This study strived to evaluate the relationship between degree of pulmonary emphysema and cardiac ventricular function in chronic obstructive pulmonary disease (COPD) patients with pulmonary hypertension (PH) using electrocardiographic-gated multidetector computed tomography (CT). Lung transplantation candidates with the diagnosis of COPD and PH were chosen for the study population, and a total of 15 patients were included. The extent of emphysema is defined as the percentage of voxels below -910 Hounsfield units in the lung windows in whole lung CT without intravenous contrast. Heart function parameters were measured by electrocardiographic-gated CT angiography. Linear regression analysis was conducted to examine the associations between percent emphysema and heart function indicators. Significant correlations were found between percent emphysema and right ventricular (RV) measurements, including RV end-diastolic volume (R(2) = 0.340, p = 0.023), RV stroke volume (R(2) = 0.406, p = 0.011), and RV cardiac output (R(2) = 0.382, p = 0.014); the correlations between percent emphysema and left ventricular function indicators were not observed. The study revealed that percent emphysema is correlated with RV dysfunction among COPD patients with PH. Based on our findings, percent emphysema can be considered for use as an indicator to predict the severity of right ventricular dysfunction among COPD patients.

Ventricular dysfunction in children with obstructive sleep apnea: radionuclide assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tal, A.; Leiberman, A.; Margulis, G.

Ventricular function was evaluated using radionuclide ventriculography in 27 children with oropharyngeal obstruction and clinical features of obstructive sleep apnea. Their mean age was 3.5 years (9 months to 7.5 years). Conventional clinical assessment did not detect cardiac involvement in 25 of 27 children; however, reduced right ventricular ejection fraction (less than 35%) was found in 10 (37%) patients (mean: 19.5 +/- 2.3% SE, range: 8-28%). In 18 patients wall motion abnormality was detected. In 11 children in whom radionuclide ventriculography was performed before and after adenotonsillectomy, right ventricular ejection fraction rose from 24.4 +/- 3.6% to 46.7 +/- 3.4%more » (P less than 0.005), and in all cases wall motion showed a definite improvement. In five children, left ventricular ejection fraction rose greater than 10% after removal of oropharyngeal obstruction. It is concluded that right ventricular function may be compromised in children with obstructive sleep apnea secondary to adenotonsillar hypertrophy, even before clinical signs of cardiac involvement are present.« less

Prevalence and Prognostic Significance of Right Ventricular Systolic Dysfunction in Patients Undergoing Transcatheter Aortic Valve Implantation.

PubMed

Lindsay, Alistair C; Harron, Katie; Jabbour, Richard J; Kanyal, Ritesh; Snow, Thomas M; Sawhney, Paramvir; Alpendurada, Francisco; Roughton, Michael; Pennell, Dudley J; Duncan, Alison; Di Mario, Carlo; Davies, Simon W; Mohiaddin, Raad H; Moat, Neil E

2016-07-01

Cardiovascular magnetic resonance (CMR) can provide important structural information in patients undergoing transcatheter aortic valve implantation. Although CMR is considered the standard of reference for measuring ventricular volumes and mass, the relationship between CMR findings of right ventricular (RV) function and outcomes after transcatheter aortic valve implantation has not previously been reported. A total of 190 patients underwent 1.5 Tesla CMR before transcatheter aortic valve implantation. Steady-state free precession sequences were used for aortic valve planimetry and to assess ventricular volumes and mass. Semiautomated image analysis was performed by 2 specialist reviewers blinded to patient treatment. Patient follow-up was obtained from the Office of National Statistics mortality database. The median age was 81.0 (interquartile range, 74.9-85.5) years; 50.0% were women. Impaired RV function (RV ejection fraction ≤50%) was present in 45 (23.7%) patients. Patients with RV dysfunction had poorer left ventricular ejection fractions (42% versus 69%), higher indexed left ventricular end-systolic volumes (96 versus 40 mL), and greater indexed left ventricular mass (101 versus 85 g/m(2); P<0.01 for all) than those with normal RV function. Median follow-up was 850 days; 21 of 45 (46.7%) patients with RV dysfunction died, compared with 43 of 145 (29.7%) patients with normal RV function (P=0.035). After adjustment for significant baseline variables, both RV ejection fraction ≤50% (hazard ratio, 2.12; P=0.017) and indexed aortic valve area (hazard ratio, 4.16; P=0.025) were independently associated with survival. RV function, measured on preprocedural CMR, is an independent predictor of mortality after transcatheter aortic valve implantation. CMR assessment of RV function may be important in the risk stratification of patients undergoing transcatheter aortic valve implantation. © 2016 American Heart Association, Inc.

Effect of left ventricular diastolic dysfunction on left atrial appendage function and thrombotic potential in nonvalvular atrial fibrillation.

PubMed

Demirçelik, Muhammed Bora; Çetin, Mustafa; Çiçekcioğlu, Hülya; Uçar, Özgül; Duran, Mustafa

2014-05-01

We aimed to investigate effects of left ventricular diastolic dysfunction on left atrial appendage functions, spontaneous echo contrast and thrombus formation in patients with nonvalvular atrial fibrillation. In 58 patients with chronic nonvalvular atrial fibrilation and preserved left ventricular systolic function, left atrial appendage functions, left atrial spontaneous echo contrast grading and left ventricular diastolic functions were evaluated using transthoracic and transoesophageal echocardiogram. Patients divided in two groups: Group D (n=30): Patients with diastolic dysfunction, Group N (n=28): Patients without diastolic dysfunction. Categorical variables in two groups were evaluated with Pearson's chi-square or Fisher's exact test. The significance of the lineer correlation between the degree of spontaneous echo contrast (SEC) and clinical measurements was evaluated with Spearman's correlation analysis. Peak pulmonary vein D velocity of the Group D was significantly higher than the Group N (p=0.006). However, left atrial appendage emptying velocity, left atrial appendage lateral wall velocity, peak pulmonary vein S, pulmonary vein S/D ratio were found to be significantly lower in Group D (p=0.028, p<0.001, p<0.001; p<0.001). Statistically significant negative correlation was found between SEC in left atrium and left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities respectively (r=-0.438, r=-0.328, r=-0.233, r=-0.447). Left atrial appendage emptying, filling, pulmonary vein S/D levels and lateral wall velocities were significantly lower in SEC 2-3-4 than SEC 1 (p=0.003, p=0.029, p<0.001, p=0.002). In patients with nonvalvular atrial fibrillation and preserved left ventricular ejection fraction, left atrial appendage functions are decreased in patients with left ventricular diastolic dysfunction. Left ventricular diastolic dysfunction may constitute a potential risk for formation of thrombus and stroke.

Simultaneous assessment of myocardial perfusion and function during mental stress in patients with chronic coronary artery disease.

PubMed

Arrighi, James A; Burg, Matthew; Cohen, Ira S; Soufer, Robert

2003-01-01

Mental stress (MS) is an important provocateur of myocardial ischemia in many patients with chronic coronary artery disease. The majority of laboratory assessments of ischemia in response to MS have included measurements of either myocardial perfusion or function alone. We performed this study to determine the relationship between alterations in perfusion and ventricular function during MS. Methods and results Twenty-eight patients with reversible perfusion defects on exercise or pharmacologic stress myocardial perfusion imaging (MPI) underwent simultaneous technetium 99m sestamibi single photon emission computed tomography (SPECT) MPI and transthoracic echocardiography at rest and during MS according to a mental arithmetic protocol. In all cases the MS study was performed within 4 weeks of the initial exercise or pharmacologic MPI that demonstrated ischemia. SPECT studies were analyzed visually with the use of a 13-segment model and quantitatively by semiautomated circumferential profile analysis. Echocardiograms were graded on a segmental model for regional wall motion on a 4-point scale. Of 28 patients, 18 (64%) had perfusion defects and/or left ventricular dysfunction develop during MS: 9 (32%) had myocardial perfusion defects develop, 6 (21%) had regional or global left ventricular dysfunction develop, and 3 (11%) had both perfusion defects and left ventricular dysfunction develop. The overall concordance between perfusion and function criteria for ischemia during MS was only 46%. Among 9 patients with MS-induced left ventricular dysfunction, 5 had new regional wall motion abnormalities and 4 had a global decrement in function. In patients with MS-induced ischemia by SPECT, the number of reversible perfusion defects was similar during both MS and exercise/pharmacologic stress (2.8 +/- 2.0 vs 3.5 +/- 1.8, P =.41). Hemodynamic changes during MS were similar whether patients were divided on the basis of perfusion defects or left ventricular dysfunction during MS. These data indicate the feasibility of simultaneous assessment of perfusion and function responses during MS. Flow and function responses to MS are frequently not concordant. These data suggest that MS-induced changes in perfusion may represent a different phenomenon than MS-induced changes in left ventricular function (either globally or regionally).

Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

PubMed

Dadpour, Bita; Dabbagh Kakhki, Vahid R; Afshari, Reza; Dorri-Giv, Masoumeh; Mohajeri, Seyed A R; Ghahremani, Somayeh

2016-12-01

Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.

Right ventricular involvement in patients with inferior myocardial infarction, correlation of electrocardiographic findings with echocardiography data.

PubMed

Javed, Sumbul; Rajani, Ali Raza; Govindaswamy, Pushparani; Radaideh, Ghazi Ahmed; Abubaraka, Harb Ahmed; Qureshi, Tariq Ilyas; Arshad, Hassaan Bin

2017-03-01

To determine the right ventricular involvement in patients with inferior myocardial infarction by echocardiography in relation to electrocardiographic findings. This observational, prospective study was conducted at Rashid Hospital, Dubai, the United Arab Emirates, from January to September 2013, and comprised patients with inferior myocardial infarction. All patients aged above 18 years were included. Right ventricular myocardial infarction was defined by the electrocardiographic criteria of > 1mV ST elevation in V4R-V5R leads. RV infarction was assessed on echocardiography by fractional area change, tricuspid annular plane systolic excursion and tricuspid annular systolic velocity by tissue Doppler imaging. SPSS 21 was used for data analysis. Of the 73 patients, there were 68(93%) men and 5(7%) women. The three modalities used to assess the right ventricular infarction showed right ventricular involvement in 36(49.3%) cases by fractional area change, 28(38.4%) cases by tricuspid annular plane systolic excursion and 31(42.5%) cases by tissue Doppler imaging in patients with inferior myocardial infarction. Tissue Doppler imaging and right ventricular function showed low degree of negative correlation (p=0.16) while the correlation between tricuspid annular plane systolic excursion and right ventricular function showed significant positive correlation (p<0.0001). Assessment of right ventricular infarction by echocardiography helped to diagnose right ventricular infarction in greater number of cases compared to surface electrocardiogram.

Minimally invasive surgical implantation of left ventricular epicardial leads for ventricular resynchronization using video-assisted thoracoscopy.

PubMed

Fernández, Angel L; García-Bengochea, José B; Ledo, Ramiro; Vega, Marino; Amaro, Antonio; Alvarez, Julián; Rubio, José; Sierra, Juan; Sánchez, Daniel

2004-04-01

Cardiac resynchronization via left ventricular or biventricular pacing is an option for selected patients with ventricular systolic dysfunction and widened QRS complex. Stimulation through a coronary vein is the technique of choice for left ventricular pacing, but this approach results in a failure rate of approximately 8%. We describe our initial experience with minimally invasive surgical implantation of left ventricular epicardial leads using video-assisted thoracoscopy. A total of 14 patients with congestive heart failure, NYHA functional class 3.2 (0.6) and mean ejection fraction 22.9 (6.8)% were included in this study. Left bundle branch block, QRS complex >140 ms and abnormal septal motion were observed in all cases. Epicardial leads were implanted on the left ventricular free wall under general anesthesia using video-assisted thoracoscopic surgery. Lead implantation was successful in 13 patients. Conversion to a small thoracotomy was necessary in one patient. All patients were extubated in the operating room. None of the patients died during their hospital stay. Follow-up showed reversal of ventricular asynchrony and significant improvement in ejection fraction and functional class. Minimally invasive surgery for ventricular resynchronization using video-assisted thoracoscopy in selected patients is a safe procedure that makes it possible to choose the best site for lead implantation and provides adequate short- and medium-term stimulation.

Right and Left Ventricular Function and Mass in Male Elite Master Athletes: A Controlled Contrast-Enhanced Cardiovascular Magnetic Resonance Study.

PubMed

Bohm, Philipp; Schneider, Günther; Linneweber, Lutz; Rentzsch, Axel; Krämer, Nadine; Abdul-Khaliq, Hashim; Kindermann, Wilfried; Meyer, Tim; Scharhag, Jürgen

2016-05-17

It is under debate whether the cumulative effects of intensive endurance exercise induce chronic cardiac damage, mainly involving the right heart. The aim of this study was to examine the cardiac structure and function in long-term elite master endurance athletes with special focus on the right ventricle by contrast-enhanced cardiovascular magnetic resonance. Thirty-three healthy white competitive elite male master endurance athletes (age range, 30-60 years) with a training history of 29±8 years, and 33 white control subjects pair-matched for age, height, and weight underwent cardiopulmonary exercise testing, echocardiography including tissue-Doppler imaging and speckle tracking, and cardiovascular magnetic resonance. Indexed left ventricular mass and right ventricular mass (left ventricular mass/body surface area, 96±13 and 62±10 g/m(2); P<0.001; right ventricular mass/body surface area, 36±7 and 24±5 g/m(2); P<0.001) and indexed left ventricular end-diastolic volume and right ventricular end-diastolic volume (left ventricular end-diastolic volume/body surface area, 104±13 and 69±18 mL/m(2); P<0.001; right ventricular end-diastolic volume/body surface area, 110±22 and 66±16 mL/m(2); P<0.001) were significantly increased in athletes in comparison with control subjects. Right ventricular ejection fraction did not differ between athletes and control subjects (52±8 and 54±6%; P=0.26). Pathological late enhancement was detected in 1 athlete. No correlations were found for left ventricular and right ventricular volumes and ejection fraction with N-terminal pro-brain natriuretic peptide, and high-sensitive troponin was negative in all subjects. Based on our results, chronic right ventricular damage in elite endurance master athletes with lifelong high training volumes seems to be unlikely. Thus, the hypothesis of an exercise-induced arrhythmogenic right ventricular cardiomyopathy has to be questioned. © 2016 American Heart Association, Inc.

Dynamic heart phantom with functional mitral and aortic valves

NASA Astrophysics Data System (ADS)

Vannelli, Claire; Moore, John; McLeod, Jonathan; Ceh, Dennis; Peters, Terry

2015-03-01

Cardiac valvular stenosis, prolapse and regurgitation are increasingly common conditions, particularly in an elderly population with limited potential for on-pump cardiac surgery. NeoChord©, MitraClipand numerous stent-based transcatheter aortic valve implantation (TAVI) devices provide an alternative to intrusive cardiac operations; performed while the heart is beating, these procedures require surgeons and cardiologists to learn new image-guidance based techniques. Developing these visual aids and protocols is a challenging task that benefits from sophisticated simulators. Existing models lack features needed to simulate off-pump valvular procedures: functional, dynamic valves, apical and vascular access, and user flexibility for different activation patterns such as variable heart rates and rapid pacing. We present a left ventricle phantom with these characteristics. The phantom can be used to simulate valvular repair and replacement procedures with magnetic tracking, augmented reality, fluoroscopy and ultrasound guidance. This tool serves as a platform to develop image-guidance and image processing techniques required for a range of minimally invasive cardiac interventions. The phantom mimics in vivo mitral and aortic valve motion, permitting realistic ultrasound images of these components to be acquired. It also has a physiological realistic left ventricular ejection fraction of 50%. Given its realistic imaging properties and non-biodegradable composition—silicone for tissue, water for blood—the system promises to reduce the number of animal trials required to develop image guidance applications for valvular repair and replacement. The phantom has been used in validation studies for both TAVI image-guidance techniques1, and image-based mitral valve tracking algorithms2.

Integration of mechanical, structural and electrical imaging to understand response to cardiac resynchronization therapy.

PubMed

Silva, Etelvino; Bijnens, Bart; Berruezo, Antonio; Mont, Lluis; Doltra, Adelina; Andreu, David; Brugada, Josep; Sitges, Marta

2014-10-01

There is extensive controversy exists on whether cardiac resynchronization therapy corrects electrical or mechanical asynchrony. The aim of this study was to determine if there is a correlation between electrical and mechanical sequences and if myocardial scar has any relevant impact. Six patients with normal left ventricular function and 12 patients with left ventricular dysfunction and left bundle branch block, treated with cardiac resynchronization therapy, were studied. Real-time three-dimensional echocardiography and electroanatomical mapping were performed in all patients and, where applicable, before and after therapy. Magnetic resonance was performed for evaluation of myocardial scar. Images were postprocessed and mechanical and electrical activation sequences were defined and time differences between the first and last ventricular segment to be activated were determined. Response to therapy was defined as a reduction in left ventricular end-systolic volume ≥ 15% after 12 months of follow-up. Good correlation between electrical and mechanical timings was found in patients with normal left ventricular function (r(2) = 0.88; P = .005) but not in those with left ventricular dysfunction (r(2) = 0.02; P = not significant). After therapy, both timings and sequences were modified and improved, except in those with myocardial scar. Despite a close electromechanical relationship in normal left ventricular function, there is no significant correlation in patients with dysfunction. Although resynchronization therapy improves this correlation, the changes in electrical activation may not yield similar changes in left ventricular mechanics particularly depending on the underlying myocardial substrate. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

Striking volume intolerance is induced by mimicking arterial baroreflex failure in normal left ventricular function.

PubMed

Funakoshi, Kouta; Hosokawa, Kazuya; Kishi, Takuya; Ide, Tomomi; Sunagawa, Kenji

2014-01-01

Patients with heart failure and preserved ejection fraction (HFpEF) are supersensitive to volume overload, and a striking increase in left atrial pressure (LAP) often occurs transiently and is rapidly resolved by intravascular volume reduction. The arterial baroreflex is a powerful regulator of intravascular stressed blood volume. We examined whether arterial baroreflex failure (FAIL) mimicked by constant carotid sinus pressure (CSP) causes a striking increase in LAP and systemic arterial pressure (AP) by volume loading in rats with normal left ventricular (LV) function. In anesthetized Sprague-Dawley rats, we isolated bilateral carotid sinuses and controlled CSP by a servo-controlled piston pump. We mimicked the normal arterial baroreflex by matching CSP to instantaneous AP and FAIL by maintaining CSP at a constant value regardless of AP. We infused dextran stepwise (infused volume [Vi]) until LAP reached 15 mm Hg and obtained the LAP-Vi relationship. We estimated the critical Vi as the Vi at which LAP reached 20 mm Hg. In FAIL, critical Vi decreased markedly from 19.4 ± 1.6 mL/kg to 15.6 ± 1.6 mL/kg (P < .01), whereas AP at the critical Vi increased (194 ± 6 mm Hg vs 163 ± 6 mm Hg; P < .01). We demonstrated that an artificial arterial baroreflex system we recently developed could fully restore the physiologic volume intolerance in the absence of native arterial baroreflex. Arterial baroreflex failure induces striking volume intolerance in the absence of LV dysfunction and may play an important role in the pathogenesis of acute heart failure, especially in states of HFpEF. Copyright © 2014 Elsevier Inc. All rights reserved.

The Ventricular Assist Device in the Life of the Child: A Phenomenological Pediatric Study

PubMed Central

van Manen, Michael A.

2017-01-01

What is it like for a child to live with an artificial heart? The use of some medical therapies in children requires developmental considerations, is associated with psychosocial consequences, and calls for ethical sensitivities. A critical case is the ventricular assist device (VAD), a mechanical pump used to support the functioning of a failing heart. As a pediatric therapy, the device can be used as a temporary solution for poor heart function, a bridge to transplantation or recovery, or as a destination therapy. While the mechanical-technical operation of the VAD is well understood, the clinical-technical aspects of young people living with this device are largely unexplored. Drawing on interviews of school-aged children, the aim of this phenomenological study is to explore how a VAD may structure or condition a child’s meaningful experience of their world outside the hospital. The driveline of an implanted VAD is the peripheral attachment, extruding through the skin to connect the controller-power supply. The materiality of the device may be interruptive, restrictive, and disturbing to the psycho-physical being and sense of self-identity of the child as a child. And while a child equipped with a VAD is not necessarily conspicuous among other children, the child may experience the device as an exposing presence, while living with the worry of a caregiver who takes on the role not simply of parent but of watchful health professional. A phenomenological understanding of the VAD should assist parents and caregiving health professionals knowing how to deal with specific issues arising in the life of the VAD child. PMID:28682718

Left ventricular filling under elevated left atrial pressure

NASA Astrophysics Data System (ADS)

Gaddam, Manikantam; Samaee, Milad; Santhanakrishnan, Arvind

2017-11-01

Left atrial pressure (LAP) is elevated in diastolic dysfunction, where left ventricular (LV) filling is impaired due to increase in ventricular stiffness. The impact of increasing LAP and LV stiffness on intraventricular filling hemodynamics remains unclear. We conducted particle image velocimetry and hemodynamics measurements in a left heart simulator (LHS) under increasing LAP and LV stiffness at a heart rate of 70 bpm. The LHS consisted of a flexible-walled LV physical model fitted within a fluid-filled chamber. LV wall motion was generated by a piston pump that imparted pressure fluctuations in the chamber. Resistance and compliance elements in the flow loop were adjusted to obtain bulk physiological hemodynamics in the least stiff LV model. Two LV models of increasing stiffness were subsequently tested under unchanged loop settings. LAP was varied between 5-20 mm Hg for each LV model, by adjusting fluid level in a reservoir upstream of the LV. For constant LV stiffness, increasing LAP lowered cardiac output (CO), while ejection fraction (EF) and E/A ratio were increased. For constant LAP, increasing LV stiffness lowered CO and EF, and increased E/A ratio. The implications of these altered hemodynamics on intraventricular filling vortex characteristics will be presented.

Pheochromocytoma-Induced Atrial Tachycardia Leading to Cardiogenic Shock and Cardiac Arrest: Resolution with Atrioventricular Node Ablation and Pacemaker Placement

PubMed Central

Bajaj, Mandeep; Cunningham, Glenn R.

2014-01-01

Pheochromocytoma should be considered in young patients who have acute cardiac decompensation, even if they have no history of hypertension. Atrioventricular node ablation and pacemaker placement should be considered for stabilizing pheochromocytoma patients with cardiogenic shock due to atrial tachyarrhythmias. A 38-year-old black woman presented with cardiogenic shock (left ventricular ejection fraction, <0.15) that did not respond to the placement of an intra-aortic balloon pump. A TandemHeart® Percutaneous Ventricular Assist Device was inserted emergently. After atrioventricular node ablation and placement of a temporary pacemaker, the TandemHeart was removed. Computed tomography of the abdomen revealed a pheochromocytoma. After placement of a permanent pacemaker, the patient underwent a right adrenalectomy. This is, to our knowledge, the first reported case of pheochromocytoma-induced atrial tachyarrhythmia that led to cardiogenic shock and cardiac arrest unresolved by the placement of 2 different ventricular assist devices, but that was completely reversed by radiofrequency ablation of the atrioventricular node and the placement of a temporary pacemaker. We present the patient's clinical, laboratory, and imaging findings, and we review the relevant literature. PMID:25593537

Risk factors for left ventricular hypertrophy: role of Na(+)-Li+ countertransport.

PubMed

Neves, P L; Faisca, M; Gomes, V; Cacodcar, S; Bernardo, I; Anunciada, A I; Viegas, E; Martins, H; da Silva, A M

1996-06-01

Left ventricular hypertrophy (LVH) is associated with an increase in cardiovascular death in essential hypertension (EH). The factors involved in LVH are multiple and complex. We looked for risk factors of LVH in a group of 28 nonobese patients with EH (mean age = 45.3 years). We analyzed the activity of several erythrocyte ion transports (Vmax of NaLi countertransport, NaKCl cotransport and NaK-pump, and the Na-leak Kp Na), the intracellular Na and the insulin sensitivity index. All these parameters were used as independent variables whereas the left ventricular mass index (LVMI) was used as the dependent variable. Variables showing a significant univariate correlation (age, time of EH, mean blood pressure and Vmax of NaLi countertransport) were introduced in a stepwise multiple regression model. Only age (P = 0.014), time of EH (P = 0.038) and Vmax of NaLi countertransport (P = 0.032) were independently associated with LVMI (R2 = 0.581, P = 0.0001). The NaLi CT, an operating mode of the NaH exchanger that facilitates cellular growth, may be a marker of LVH, and consequently a marker of increased cardiovascular risk.

Impact of chronic obstructive pulmonary diseases on left ventricular diastolic function in hospitalized elderly patients.

PubMed

Huang, Ying-Shuo; Feng, Ying-Chao; Zhang, Jian; Bai, Li; Huang, Wei; Li, Min; Sun, Ying

2015-01-01

To evaluate the impact of chronic obstructive pulmonary disease (COPD) on left ventricular (LV) diastolic function in hospitalized elderly patients. This was a case-control observational study of 148 consecutive hospitalized elderly patients (≥65 years old): 73 subjects without COPD as controls and 75 patients with COPD. Mild-to-moderate COPD was defined as stages 1 and 2, while severe and very severe COPD was defined as stages 3 and 4, according to the Global Initiative for Chronic Obstructive Lung Disease guidelines. Clinical characteristics and echocardiographic parameters were analyzed and compared. Compared with the control group, patients with COPD had a higher frequency of LV diastolic dysfunction and heart failure with preserved ejection fraction. Smoking frequency, frequency of cerebrovascular diseases and diabetes, and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were higher in the COPD group (all P<0.05). COPD patients showed more abnormalities in diastolic function (E/e': 11.51±2.50 vs 10.42±3.25, P=0.047), but no differences in systolic function and right ventricular function (all P>0.05). Patients with severe/very severe COPD showed no differences in LV diastolic function compared to patients with mild/moderate COPD (P>0.05), but serum NT-proBNP levels were higher in severe/very severe COPD (P<0.05). Results suggest that early-stage COPD may have an impact on the LV diastolic function. Severe COPD mainly affected right ventricular function. In hospitalized elderly patients with COPD, LV diastolic dysfunction should be taken into account together with right ventricular function.

Role of left ventricular twist mechanics in cardiomyopathies, dance of the helices

PubMed Central

Kauer, Floris; Geleijnse, Marcel Leonard; van Dalen, Bastiaan Martijn

2015-01-01

Left ventricular twist is an essential part of left ventricular function. Nevertheless, knowledge is limited in “the cardiology community” as it comes to twist mechanics. Fortunately the development of speckle tracking echocardiography, allowing accurate, reproducible and rapid bedside assessment of left ventricular twist, has boosted the interest in this important mechanical aspect of left ventricular deformation. Although the fundamental physiological role of left ventricular twist is undisputable, the clinical relevance of assessment of left ventricular twist in cardiomyopathies still needs to be established. The fact remains; analysis of left ventricular twist mechanics has already provided substantial pathophysiological understanding on a comprehensive variety of cardiomyopathies. It has become clear that increased left ventricular twist in for example hypertrophic cardiomyopathy may be an early sign of subendocardial (microvascular) dysfunction. Furthermore, decreased left ventricular twist may be caused by left ventricular dilatation or an extensive myocardial scar. Finally, the detection of left ventricular rigid body rotation in noncompaction cardiomyopathy may provide an indispensible method to objectively confirm this difficult diagnosis. All this endorses the value of left ventricular twist in the field of cardiomyopathies and may further encourage the implementation of left ventricular twist parameters in the “diagnostic toolbox” for cardiomyopathies. PMID:26322187

Cardiac tissue Doppler imaging in sports medicine.

PubMed

Krieg, Anne; Scharhag, Jürgen; Kindermann, Wilfried; Urhausen, Axel

2007-01-01

The differentiation of training-induced cardiac adaptations from pathological conditions is a key issue in sports cardiology. As morphological features do not allow for a clear delineation of early stages of relevant pathologies, the echocardiographic evaluation of left ventricular function is the technique of first choice in this regard. Tissue Doppler imaging (TDI) is a relatively recent method for the assessment of cardiac function that provides direct, local measurements of myocardial velocities throughout the cardiac cycle. Although it has shown a superior sensitivity in the detection of ventricular dysfunction in clinical and experimental studies, its application in sports medicine is still rare. Besides technical factors, this may be due to a lack in consensus on the characteristics of ventricular function in relevant conditions. For more than two decades there has been an ongoing debate on the existence of a supernormal left ventricular function in athlete's heart. While results from traditional echocardiography are conflicting, TDI studies established an improved diastolic function in endurance-trained athletes with athlete's heart compared with controls.The influence of anabolic steroids on cardiac function also has been investigated by standard echocardiographic techniques with inconsistent results. The only TDI study dealing with this topic demonstrated a significantly impaired diastolic function in bodybuilders with long-term abuse of anabolic steroids compared with strength-trained athletes without abuse of anabolic steroids and controls, respectively.Hypertrophic cardiomyopathy is the most frequent cause of sudden death in young athletes. However, in its early stages, it is difficult to distinguish from athlete's heart. By means of TDI, ventricular dysfunction in hypertrophic cardiomyopathy can be disclosed even before the development of left ventricular hypertrophy. Also, a differentiation of left ventricular hypertrophy due to hypertrophic cardiomyopathy or systemic hypertension is possible by TDI. Besides the evaluation of different forms of left ventricular hypertrophy, the diagnosis of myocarditis is also of particular importance in athletes. Today, it still requires myocardial biopsy. The analysis of focal disturbances in myocardial velocities might be a promising non-invasive method; however, systematic validation studies are lacking. An important future issue for the implementation of TDI into routine examination will be the standardisation of procedures and the establishment of significant reference values for the above-mentioned conditions. Innovative TDI parameters also merit further investigation.

[Assessment of the right ventricular anatomy and function by advanced echocardiography: pathological and physiological insights].

PubMed

Lakatos, Bálint; Kovács, Attila; Tokodi, Márton; Doronina, Alexandra; Merkely, Béla

2016-07-01

Accurate assessment of right ventricular geometry and function is of high clinical importance. However, several limitations have to be taken into consideration if using conventional echocardiographic parameters. Advanced echocardiographic techniques, such as speckle-tracking analysis or 3D echocardiography are reliable and simple tools providing a cost-effective and non-invasive alternative of current modalities used to characterize the right ventricle. There is a growing interest in the diagnostic and prognostic value of these methods regarding pathological (right ventricular infarction, pulmonary hypertension, arrhythmogenic right ventricular dysplasia, follow-up of heart transplantation) and even physiological (athlete's heart) alterations of the right ventricle. Orv. Hetil., 2016, 157(29), 1139-1146.

Pre-operative risk factors of bleeding and stroke during left ventricular assist device support: an analysis of more than 900 HeartMate II outpatients.

PubMed

Boyle, Andrew J; Jorde, Ulrich P; Sun, Benjamin; Park, Soon J; Milano, Carmelo A; Frazier, O Howard; Sundareswaran, Kartik S; Farrar, David J; Russell, Stuart D

2014-03-11

This study sought to determine the pre-operative risk factors related to late bleeding, stroke, and pump thrombosis in patients with HeartMate II (HMII) left ventricular assist devices (LVADs) (Thoratec Corporation, Pleasanton, California) that might influence tailored improvements in patient management. Adverse events in LVAD patients remain high. It is unclear whether pre-operative characteristics influence the likelihood of the development of post-operative hemorrhagic or thrombotic complications. Knowing which patients are at greater risk might assist in tailoring anticoagulation therapy for certain patients. Advanced heart failure patients (n = 956) discharged from the hospital after LVAD implantation in the HMII bridge to transplantation (n = 405) and destination therapy (n = 551) clinical trials were retrospectively evaluated. Bleeding requiring surgery or transfusion of >2 U of packed red blood cells, stroke (hemorrhagic and ischemic), and pump thrombosis were tracked from hospital discharge until patient outcome. Adverse event rates for post-discharge bleeding (0.67 events/patient-year) were higher than those for hemorrhagic stroke (0.05), ischemic stroke (0.04), and pump thrombosis (0.03). The main sites of bleeding included gastrointestinal (45% of events), wound (12%), and epistaxis (4%). Older age (>65 years) (hazard ratio [HR]: 1.31), lower pre-operative hematocrit (≤31%) (HR: 1.31), ischemic etiology (HR: 1.35), and female (HR: 1.45) were statistically significant multivariable risk factors for bleeding. Female (HR: 1.92) and 65 years of age and younger (HR: 1.94) were multivariable risk factors for hemorrhagic stroke, whereas female (HR: 1.84) and history of diabetes (HR: 1.99) were risk factors for ischemic stroke. Female (HR: 1.90) and higher body mass index (HR: 1.71/10 kg/m(2) increase) were also multivariable risk factors for pump thrombosis. The risk of bleeding and thrombotic events during LVAD support differs by patient demographics, including sex, age, body mass index, and etiology of heart failure. Further studies should focus on the potential of tailored anticoagulation strategies in these subgroups. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Von Willebrand factor, a versatile player in gastrointestinal bleeding in left ventricular assist device recipients?

PubMed

Fischer, Quentin; Huisse, Marie-Geneviève; Voiriot, Guillaume; Caron, Claudine; Lepage, Laurent; Dilly, Marie-Pierre; Nataf, Patrick; Ajzenberg, Nadine; Kirsch, Matthias

2015-01-01

Bleeding originating in the gastrointestinal (GI) tract is one of the most common adverse events after left ventricular assist device (LVAD) implantation. In these patients, GI bleeding appears to be the consequence of altered hemostasis on the one hand and alterations of the GI microvasculature on the other. We report the case of a patient who suffered repeated, severe GI bleeding early after implantation of a HeartMate II continuous-flow LVAD. After failure of conventional treatment strategies, GI bleeding was controlled using repeated transfusions of a purified von Willebrand factor (VWF) concentrate, almost devoid of Factor VIII (Wilfactin, LFB). No episodes of pump thrombosis were noted. Subsequent to VWF transfusions, we observed a progressive normalization of circulating vascular endothelial growth factor levels. Our data raise the possibility that, in addition to its hemostatic properties, transfusions of VWF might have acted as an antiangiogenic factor. © 2014 AABB.

HeartMate II left ventricular assist system: from concept to first clinical use.

PubMed

Griffith, B P; Kormos, R L; Borovetz, H S; Litwak, K; Antaki, J F; Poirier, V L; Butler, K C

2001-03-01

The HeartMate II left ventricular assist device (LVAD) (ThermoCardiosystems, Inc, Woburn, MA) has evolved from 1991 when a partnership was struck between the McGowan Center of the University of Pittsburgh and Nimbus Company. Early iterations were conceptually based on axial-flow mini-pumps (Hemopump) and began with purge bearings. As the project developed, so did the understanding of new bearings, computational fluid design and flow visualization, and speed control algorithms. The acquisition of Nimbus by ThermoCardiosystems, Inc (TCI) sped developments of cannulas, controller, and power/monitor units. The system has been successfully tested in more than 40 calves since 1997 and the first human implant occurred in July 2000. Multicenter safety and feasibility trials are planned for Europe and soon thereafter a trial will be started in the United States to test 6-month survival in end-stage heart failure.

Right ventricular function and N-terminal pro-brain natriuretic peptide levels in adult patients with simple dextro-transposition of the great arteries.

PubMed

Martínez-Quintana, Efrén; Marrero-Negrín, Natalia; Gopar-Gopar, Silvia; Rodríguez-González, Fayna

2017-06-01

Dextro-transposition of the great arteries (d-TGA) patients is at high risk of developing right ventricular dysfunction and tricuspid regurgitation in adulthood. Determining the relation between echocardiographic parameters, N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels and the New York Heart Association (NYHA) functional class may help determining the best time to operate them. Patients with simple d-TGA operated in infancy with an atrial switch procedure (Mustard or Senning operation) were followed up in our Adult Congenital Heart Disease Unit. Analytical, echocardiographic, and clinical parameters were determined to evaluate the correlation between right echocardiographic ventricular function, NT-pro-BNP levels, and NYHA functional class. Twenty-four patients with d-TGA were operated in infancy of whom 17 alive patients had simple d-TGA. Nine patients had NT-pro-BNP levels lower than 200 pg/mL and eight patients were above 200 pg/mL. Patients with lower hemoglobin concentration, higher right ventricular diameter or under diuretic treatment showed significant higher NT-pro-BNP levels (above 200 pg/dL). The Spearman test showed a positive correlation between basal right ventricular diameter and tricuspid regurgitation with pro NT BNP levels (correlation coefficient of .624; P=.017 and .490; P=.046, respectively) and a negative correlation with the right ventricle fractional area change (-.508, P=.045). No correlation was seen between NT-pro-BNP levels and the rest of echocardiographic parameters or the NYHA functional class. NT-pro-BNP levels showed a positive correlation with basal right ventricular diameter and tricuspid regurgitation but not with NYHA association functional class in d-TGA patients. © 2017, Wiley Periodicals, Inc.

Central-Approach Surgical Repair of Coarctation of the Aorta with a Back-up Left Ventricular Assist Device for an Infant Presenting with Severe Left Ventricular Dysfunction.

PubMed

Kim, Tae Hoon; Shin, Yu Rim; Kim, Young Sam; Kim, Do Jung; Kim, Hyohyun; Shin, Hong Ju; Htut, Aung Thein; Park, Han Ki

2015-12-01

A two-month-old infant presented with coarctation of the aorta, severe left ventricular dysfunction, and moderate to severe mitral regurgitation. Through median sternotomy, the aortic arch was repaired under cardiopulmonary bypass and regional cerebral perfusion. The patient was postoperatively supported with a left ventricular assist device for five days. Left ventricular function gradually improved, eventually recovering with the concomitant regression of mitral regurgitation. Prompt surgical repair of coarctation of the aorta is indicated for patients with severe left ventricular dysfunction. A central approach for surgical repair with a back-up left ventricular assist device is a safe and effective treatment strategy for these patients.

An intraventricular axial flow blood pump integrated with a bearing purge system.

PubMed

Yamazaki, K; Kormos, R; Mori, T; Umezu, M; Kameneva, M; Antaki, J; Outa, E; Litwak, P; Kerrigan, J; Tomczak, J

1995-01-01

The future development of implantable axial flow blood pumps must address two major issues: mechanically induced hemolysis and shaft seal reliability. The recent revisions to our miniature intraventricular axial flow left ventricular assist device (LVAD) were aimed particularly at addressing these concerns. To improve hemocompatibility, a new impeller has been designed according to the following criteria: 1) gradual pressure rise along the blade chord; 2) minimized local fluid acceleration to prevent cavitation; 3) minimum surface roughness; and 4) radius edges. Subsequent in vitro hemolysis tests conducted with bovine and ovine blood have demonstrated very low hemolysis (normalized index of hemolysis = 0.0051 +/- 0.0047 g/100 L) with this new impeller design. To address the need for a reliable seal, we have developed a purged seal system consisting of a miniature lip seal and ceramic pressure groove journal bearing that also acts as a purge pump. Several spiral grooves formed on the bearing surface provide viscous pumping of the purge fluid, generating more than 3,000 mmHg at 10,000 rpm. This purge flow flushes the lip seal and prevents blood backflow into the bearing. We have found this purge pump to offer several advantages because it is simple, compact, durable, does not require separate actuation, and offers a wide range of flow, depending upon the groove design. In vivo animal tests demonstrated the potential of the purged seal system.

Initial clinical trial of a closed loop, fully automatic intra-aortic balloon pump.

PubMed

Kantrowitz, A; Freed, P S; Cardona, R R; Gage, K; Marinescu, G N; Westveld, A H; Litch, B; Suzuki, A; Hayakawa, H; Takano, T

1992-01-01

A new generation, closed loop, fully automatic intraaortic balloon pump (CL-IABP) system continuously optimizes diastolic augmentation by adjusting balloon pump parameters beat by beat without operator intervention. In dogs in sinus rhythm and with experimentally induced arrhythmias, the new CL-IABP system provided safe, effective augmentation. To investigate the system's suitability for clinical use, 10 patients meeting standard indications for IABP were studied. The patients were pumped by the fully automatic IABP system for an average of 20 hr (range, 1-48 hr). At start-up, the system optimized pumping parameters within 7-20 sec. Evaluation of 186 recordings made at hourly intervals showed that inflation began within 20 msec of the dicrotic notch 99% of the time. In 100% of the recordings, deflation straddled the first half of ventricular ejection. Peak pressure across the balloon membrane averaged 55 mmHg and, in no case, exceeded 100 mmHg. Examination of the data showed that as soon as the system was actuated it provided consistently beneficial diastolic augmentation without any further operator intervention. Eight patients improved and two died (one of irreversible cardiogenic shock and one of ischemic cardiomyopathy). No complications were attributable to the investigational aspects of the system. A fully automated IABP is feasible in the clinical setting, and it may have advantages relative to current generation IABP systems.

[Acute left ventricular systolic dysfunction after pericardial effusion drainage].

PubMed

Brauner, F B; Nunes, C E; Fabra, R; Riesgo, A; Thomé, L G

1997-12-01

A patient with a thymoma and initially normal ventricular systolic function developed cardiac tamponade, which was relieved by pericardiocentesis. After four days, the tumor was removed and, one week after the relief of tamponade, she developed severe left ventricular systolic dysfunction, that recovered in three days with venous therapy.

Systolic ventricular filling.

PubMed

Torrent-Guasp, Francisco; Kocica, Mladen J; Corno, Antonio; Komeda, Masashi; Cox, James; Flotats, A; Ballester-Rodes, Manel; Carreras-Costa, Francesc

2004-03-01

The evidence of the ventricular myocardial band (VMB) has revealed unavoidable coherence and mutual coupling of form and function in the ventricular myocardium, making it possible to understand the principles governing electrical, mechanical and energetical events within the human heart. From the earliest Erasistratus' observations, principal mechanisms responsible for the ventricular filling have still remained obscured. Contemporary experimental and clinical investigations unequivocally support the attitude that only powerful suction force, developed by the normal ventricles, would be able to produce an efficient filling of the ventricular cavities. The true origin and the precise time frame for generating such force are still controversial. Elastic recoil and muscular contraction were the most commonly mentioned, but yet, still not clearly explained mechanisms involved in the ventricular suction. Classical concepts about timing of successive mechanical events during the cardiac cycle, also do not offer understandable insight into the mechanism of the ventricular filling. The net result is the current state of insufficient knowledge of systolic and particularly diastolic function of normal and diseased heart. Here we summarize experimental evidence and theoretical backgrounds, which could be useful in understanding the phenomenon of the ventricular filling. Anatomy of the VMB, and recent proofs for its segmental electrical and mechanical activation, undoubtedly indicates that ventricular filling is the consequence of an active muscular contraction. Contraction of the ascendent segment of the VMB, with simultaneous shortening and rectifying of its fibers, produces the paradoxical increase of the ventricular volume and lengthening of its long axis. Specific spatial arrangement of the ascendent segment fibers, their interaction with adjacent descendent segment fibers, elastic elements and intra-cavitary blood volume (hemoskeleton), explain the physical principles involved in this action. This contraction occurs during the last part of classical systole and the first part of diastole. Therefore, the most important part of ventricular diastole (i.e. the rapid filling phase), in which it receives >70% of the stroke volume, belongs to the active muscular contraction of the ascendent segment. We hope that these facts will give rise to new understanding of the principal mechanisms involved in normal and abnormal diastolic heart function.

Added clinical value of applying myocardial deformation imaging to assess right ventricular function.

PubMed

Sokalskis, Vladislavs; Peluso, Diletta; Jagodzinski, Annika; Sinning, Christoph

2017-06-01

Right heart dysfunction has been found to be a strong prognostic factor predicting adverse outcome in various cardiopulmonary diseases. Conventional echocardiographic measurements can be limited by geometrical assumptions and impaired reproducibility. Speckle tracking-derived strain provides a robust quantification of right ventricular function. It explicitly evaluates myocardial deformation, as opposed to tissue Doppler-derived strain, which is computed from tissue velocity gradients. Right ventricular longitudinal strain provides a sensitive tool for detecting right ventricular dysfunction, even at subclinical levels. Moreover, the longitudinal strain can be applied for prognostic stratification of patients with pulmonary hypertension, pulmonary embolism, and congestive heart failure. Speckle tracking-derived right atrial strain, right ventricular longitudinal strain-derived mechanical dyssynchrony, and three-dimensional echocardiography-derived strain are emerging imaging parameters and methods. Their application in research is paving the way for their clinical use. © 2017, Wiley Periodicals, Inc.

Physiologic pacing: new modalities and pacing sites.

PubMed

Padeletti, Luigi; Lieberman, Randy; Valsecchi, Sergio; Hettrick, Douglas A

2006-12-01

Right ventricular (RV) apical pacing impairs left ventricular function by inducing dys-synchronous contraction and relaxation. Chronic RV apical pacing is associated with an increased risk of atrial fibrillation, morbidity, and even mortality. These observations have raised questions regarding the appropriate pacing mode and site, leading to the introduction of algorithms and new pacing modes to reduce the ventricular pacing burden in dual chamber devices, and a shift of the pacing site away from the RV apex. However, further investigations are required to assess the long-term results of pacing from alternative sites in the right ventricle, because long-term results so far are equivocal. The potential benefit of prophylactic biventricular, mono-chamber left ventricular, and bifocal RV pacing should be explored in selected patients with a narrow QRS complex, especially those with impaired left ventricular function. His bundle pacing is a promising and evolving technique that requires improvements in lead technology.

Right ventricular presystolic peak velocity represents right ventricular function in stable patients.

PubMed

Giovanardi, Paolo; Tincani, Enrico; Stefanelli, Guglielmo; Turrini, Fabrizio; Magnavacchi, Paolo; Sansoni, Stefania; Zennaro, Mauro; Pinelli, Giovanni; Tondi, Stefano

2017-04-01

Right ventricular (RV) function is difficult to be measured but plays a role in morbility and mortality of patients with cardiopulmonary diseases, so many echocardiographic parameters have been developed from M-mode, B-mode and Doppler tissue imaging (DTI) evaluation. Right ventricular presystolic peak velocity (RVPrP) measured with DTI of the tricuspidal annulus and its changes in RV dysfunction have never been assessed in a patient's cohort of stable patients with cardiovascular risk factors. RVPrP velocity could have a role in RV function evaluation; this study addresses such issue. Four hundred thirty-six consecutive patients were submitted to a complete echocardiographic examination with the contemporary evaluation of the following RV function indexes: Tricuspid Annulus Plane Systolic Excurtion (TAPSE), RV Systolic Peak (RVSyP) and RVPrP. Pulmonary artery systolic pressure (PASP), left ventricular and RV diastolic function were also evaluated. According to TAPSE and RVSyP taken alone or in combination, 113 patients had RV dysfunction, while 323 patients had normal RV function. RVPrP was reduced in patient's group with RV dysfunction with respect to patient's group with preserved RV function (16.48±7.3 cm/s vs. 23.98±8.4 cm/s, respectively, P<0.001). RVPrP was related with RVSyP (P<0.001) and with TAPSE (P=0.002). TAPSE and RVSyP revealed a poor concordance to define RV dysfunction. PASP was higher in patient's group with reduced RV function (P=0.033). The study showed RVPrP able to detect stable patients with RV dysfunction.

Implantation of the Medtronic Harmony Transcatheter Pulmonary Valve Improves Right Ventricular Size and Function in an Ovine Model of Postoperative Chronic Pulmonary Insufficiency.

PubMed

Schoonbeek, Rosanne C; Takebayashi, Satoshi; Aoki, Chikashi; Shimaoka, Toru; Harris, Matthew A; Fu, Gregory L; Kim, Timothy S; Dori, Yoav; McGarvey, Jeremy; Litt, Harold; Bouma, Wobbe; Zsido, Gerald; Glatz, Andrew C; Rome, Jonathan J; Gorman, Robert C; Gorman, Joseph H; Gillespie, Matthew J

2016-10-01

Pulmonary insufficiency is the nexus of late morbidity and mortality after transannular patch repair of tetralogy of Fallot. This study aimed to establish the feasibility of implantation of the novel Medtronic Harmony transcatheter pulmonary valve (hTPV) and to assess its effect on pulmonary insufficiency and ventricular function in an ovine model of chronic postoperative pulmonary insufficiency. Thirteen sheep underwent baseline cardiac magnetic resonance imaging, surgical pulmonary valvectomy, and transannular patch repair. One month after transannular patch repair, the hTPV was implanted, followed by serial magnetic resonance imaging and computed tomography imaging at 1, 5, and 8 month(s). hTPV implantation was successful in 11 animals (85%). There were 2 procedural deaths related to ventricular fibrillation. Seven animals survived the entire follow-up protocol, 5 with functioning hTPV devices. Two animals had occlusion of hTPV with aneurysm of main pulmonary artery. A strong decline in pulmonary regurgitant fraction was observed after hTPV implantation (40.5% versus 8.3%; P=0.011). Right ventricular end diastolic volume increased by 49.4% after transannular patch repair (62.3-93.1 mL/m 2 ; P=0.028) but was reversed to baseline values after hTPV implantation (to 65.1 mL/m 2 at 8 months, P=0.045). Both right ventricular ejection fraction and left ventricular ejection fraction were preserved after hTPV implantation. hTPV implantation is feasible, significantly reduces pulmonary regurgitant fraction, facilitates right ventricular volume improvements, and preserves biventricular function in an ovine model of chronic pulmonary insufficiency. This percutaneous strategy could potentially offer an alternative for standard surgical pulmonary valve replacement in dilated right ventricular outflow tracts, permitting lower risk, nonsurgical pulmonary valve replacement in previously prohibitive anatomies. © 2016 American Heart Association, Inc.

[Cardiac structure and function in patients with obstructive sleep apnea syndrome and co-prevalent arterial hypertension. Influence of CPAP therapy].

PubMed

Duchna, Hans-Werner; Myslinski, Wojciech; Dichmann, Manuel; Rasche, Kurt; Schultze-Werninghaus, Gerhard; Orth, Maritta

2006-01-15

30% of patients with arterial hypertension (AH) are supposed to have a co-prevalent obstructive sleep apnea syndrome (OSAS). Hence, the influence of CPAP (continuous positive airway pressure) therapy on cardiac structure and function was investigated in medically treated patients with AH and co-prevalent OSAS. In all patients AH was treated for at least 5 years. Matched pairs concerning anthropometric data, medical therapy and duration of AH, and severity of OSAS were investigated: 20 patients with untreated OSAS were compared to 20 patients with CPAP therapy for at least 6 months. Further cardiopulmonary diseases were excluded. Cardiac structure and function were assessed echocardiographically. Patients under CPAP therapy had significantly better diastolic left ventricular function, a lower left ventricular mass index, and significantly less frequent signs of left ventricular (eccentric) hypertrophy than patients with untreated OSAS. Furthermore, differences were significant concerning right ventricular wall thickness and mean pulmonary artery pressure. CPAP therapy positively influences left and right cardial structure and function in addition to antihypertensive medication in patients with AH and co-prevalent OSAS.

Cardiac structure and function in the obese: a cardiovascular magnetic resonance imaging study.

PubMed

Danias, Peter G; Tritos, Nicholas A; Stuber, Matthias; Kissinger, Kraig V; Salton, Carol J; Manning, Warren J

2003-07-01

Obesity is a major health problem in the Western world. Among obese subjects cardiac pathology is common, but conventional noninvasive imaging modalities are often suboptimal for detailed evaluation of cardiac structure and function. We investigated whether cardiovascular magnetic resonance imaging (CMR) can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. In this prospective cross-sectional study, CMR was used to quantify left and right ventricular volumes, ejection fraction, mass, cardiac output, and apical left ventricular rotation in 25 clinically healthy obese men and 25 age-matched lean controls. Obese subjects had higher left ventricular mass (203 +/- 38 g vs. 163 +/- 22 g, p < 0.001), end-diastolic volume (176 +/- 29 mL vs. 156 +/- 25 mL, p < 0.05), and cardiac output (8.2 +/- 1.2 L/min vs. 6.4 +/- 1.3 L/min, p < 0.001). The obese also had increased right ventricular mass (105 +/- 25 g vs. 87 +/- 18 g, p < 0.005) and end-diastolic volume (179 +/- 36 mL vs. 155 +/- 28 mL, p < 0.05). When indexed for height, differences in left and right ventricular mass, and left ventricular end-diastolic volume remained significant. Apical left ventricular rotation and rotational velocity patterns were also different between obese and lean subjects. Obesity is independently associated with remodeling of the heart. Cardiovascular magnetic resonance imaging identifies subtle cardiac abnormalities and may be the preferred imaging technique to evaluate cardiac structure and function in the obese.

Left ventricular function during lower body negative pressure

NASA Technical Reports Server (NTRS)

Ahmad, M.; Blomqvist, C. G.; Mullins, C. B.; Willerson, J. T.

1977-01-01

The response of the human left ventricle to lower body negative pressure (LBNP) and the relation between left ventricular function and hemodynamic response were investigated. Ventricular function curves relating stroke volume to end-diastolic volume were obtained in 12 normal men. Volume data were derived from echocardiographic measurements of left ventricular end-systolic and end-diastolic diameters at rest and during lower body negative pressure (LBNP) at minus 40 mm Hg. End-diastolic volume decreased by 19% and stroke volume by 22%. There were no significant changes in heart rate, arterial blood pressure, or end-systolic volume. Thus, moderate levels of LBNP significantly reduce preload and stroke volume without affecting contractile state. The absence of significant changes in heart rate and arterial blood pressure in the presence of a significant reduction in stroke volume is consistent with an increase in systemic peripheral resistance mediated by low-pressure baroreceptors.

Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function.

PubMed

van Huls van Taxis, Carine F B; Piers, Sebastiaan R D; de Riva Silva, Marta; Dekkers, Olaf M; Pijnappels, Daniël A; Schalij, Martin J; Wijnmaalen, Adrianus P; Zeppenfeld, Katja

2015-12-01

High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function. Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1-Q3, 16-60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1-Q3 50-156), and cESS 143±35 kdyne/cm(2). Fatigue was associated with higher baseline NT-proBNP and cESS (P<0.001, P=0.011, respectively). After sustained successful ablation, achieved in 81%, NT-proBNP and cESS decreased significantly (P<0.001 and P=0.036, respectively). Fatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged. In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function. © 2015 American Heart Association, Inc.

QT dispersion and ventricular arrhythmias in children with primary mitral valve prolapse

PubMed Central

İmamoğlu, Ebru Yalın; Eroğlu, Ayşe Güler

2016-01-01

Aim: To investigate ventricular arrhythmias in children with primary mitral valve prolapse and to evaluate its relation with QT length, QT dispersion, autonomic function tests and heart rate variability measurements. Material and Methods: Fourty two children with mitral valve prolapse and 32 healthy children were enrolled into the study. Twelve-lead electrocardiograms, autonomic function tests, echocardiography and 24-hour rhythm Holter tests were performed. Electrocardiograms were magnified digitally. The QT length was corrected according to heart rate. The patients were grouped according to the number of premature ventricular contractions and presence of complex ventricular arhythmia in the 24-hour rhythm Holter monitor test. Heart rate variability measurements were calculated automatically from the 24-hour rhythm Holter monitor test. Orthostatic hypotension and resting heart rate were used as autonomic function tests. Results: The mean age was 13.9±3.3 years in the patient group and 14.6±3.1 years in the control group (p>0.05). Thirty four of the patients (81%) were female and eight (19%) were male. Twenty five of the control subjects (78%) were female and seven (22%) were male. The QT dispersion and heart rate corrected QT interval were found to be significantly increased in the children with primary mitral valve prolapse when compared with the control group (56±16 ms vs. 43±11 ms, p=0.001; 426±25 ms vs. 407±26 ms, p=0.002, respectively). In 24-hour rhythm Holter monitor tests, ventricular arrhythmias were found in 21 out of 42 patients (50%) and 6 out of 32 control subjects (18.8%) (p=0.006). QT dispersion was found to be significantly increased in patients with premature ventricular contractions ≥ 10/day and/or complex ventricular arrhythmias compared to the control group without ventricular premature beats (p=0.002). There was no significant difference in autonomic function tests and heart rate variability measurements between the patient and control groups. Conclusions: The noted increase in QT dispersion may be a useful indicator for the clinician in the evaluation of impending ventricular arrhythmias in children with primary mitral valve prolapse. PMID:27738397

Left ventricular rotation and torsion in patients with perimembranous ventricular septal defect.

PubMed

Zhuang, Yan; Yong, Yong-hong; Yao, Jing; Ji, Ling; Xu, Di

2014-03-01

Assessment of left ventricular (LV) rotation has become an important approach for quantifying LV function. In this study, we sought to analyze LV rotation and twist using speckle tracking imaging (STI) in adult patients with isolated ventricular septal defects. Using STI, the peak rotation and time to peak rotation of 6 segments in basal and apical short-axis were measured, respectively, in 32 patients with ventricular septal defect and 30 healthy subjects as controls. The global rotation of the 6 segments in basal and apical and LV twist versus time profile were drawn, the peak rotation and twist of LV were calculated. All the time to peak rotation/twist were expressed as a percentage of end-systole (end-systole = 100%). Left ventricular ejection fraction was measured by biplane Simpson method. In patients group, the peak rotation of posterior, inferior, and postsept wall in basal was higher(P ≤ 0.05) and LV twist was also higher (P ≤ 0.05) than healthy controls. There were no significant differences between 2 groups in the peak rotation of the other 9 segments and left ventricular ejection fraction. Different from the control group, the time to peak rotation of the 6 segments in basal were delayed and the global rotation of the base was delayed (P ≤ 0.05) in ventricular septal defect group. Left ventricular volume overload due to ventricular septal defect has significant effect on LV rotation and twist, and LV rotation and twist may be a new index predicting LV systolic function. © 2013, Wiley Periodicals, Inc.

Spatially divergent cardiac responses to nicotinic stimulation of ganglionated plexus neurons in the canine heart.

PubMed

Cardinal, René; Pagé, Pierre; Vermeulen, Michel; Ardell, Jeffrey L; Armour, J Andrew

2009-01-28

Ganglionated plexuses (GPs) are major constituents of the intrinsic cardiac nervous system, the final common integrator of regional cardiac control. We hypothesized that nicotinic stimulation of individual GPs exerts divergent regional influences, affecting atrial as well as ventricular functions. In 22 anesthetized canines, unipolar electrograms were recorded from 127 atrial and 127 ventricular epicardial loci during nicotine injection (100 mcg in 0.1 ml) into either the 1) right atrial (RA), 2) dorsal atrial, 3) left atrial, 4) inferior vena cava-inferior left atrial, 5) right ventricular, 6) ventral septal ventricular or 7) cranial medial ventricular (CMV) GP. In addition to sinus and AV nodal function, neural effects on atrial and ventricular repolarization were identified as changes in the area subtended by unipolar recordings under basal conditions and at maximum neurally-induced effects. Animals were studied with intact AV node or following ablation to achieve ventricular rate control. Atrial rate was affected in response to stimulation of all 7 GPs with an incidence of 50-95% of the animals among the different GPs. AV conduction was affected following stimulation of 6/7 GP with an incidence of 22-75% among GPs. Atrial and ventricular repolarization properties were affected by atrial as well as ventricular GP stimulation. Distinct regional patterns of repolarization changes were identified in response to stimulation of individual GPs. RAGP predominantly affected the RA and posterior right ventricular walls whereas CMVGP elicited biatrial and biventricular repolarization changes. Spatially divergent and overlapping cardiac regions are affected in response to nicotinic stimulation of neurons in individual GPs.

US FDA perspective on regulatory issues affecting circulatory assist devices.

PubMed

Sapirstein, Wolf; Chen, Eric; Swain, Julie; Zuckerman, Bram

2006-11-01

There has been a rapid development in mechanical circulatory support systems in the decade since the US FDA first approved a mechanical device to provide the circulatory support lacking from a failing heart. Devices are presently approved for marketing by the FDA to replace a failing ventricle, the Ventricular Assist Device or the entire heart, Total Artificial Heart. Contemporaneous with, and permitted by, improvement in technology and design, devices have evolved from units located extracorporeally to paracorporeal systems and totally implanted devices. Clinical studies have demonstrated a parallel improvement in the homeostatic adequacy of the circulatory support provided. Thus, while the circulatory support was initially tolerated for short periods to permit recovery of cardiac function, this technology eventually provided effective circulatory support for increasing periods that permitted the FDA to approve devices for bridging patients in end-stage cardiac failure awaiting transplant and eventually a device for destination therapy where patients in end-stage heart failure are not cardiac transplant candidates. The approved devices have relied on displacement pumps that mimic the pulsatility of the physiological system. Accelerated development of more compact devices that rely on alternative pump mechanisms have challenged both the FDA and device manufacturers to assure that the regulatory requirements for safety and effectiveness are met for use of mechanical circulatory support systems in expanded target populations. An FDA regulatory perspective is reviewed of what can be a potentially critical healthcare issue.

Levosimendan Prevents Pressure-Overload-induced Right Ventricular Failure.

PubMed

Hillgaard, Thomas Krarup; Andersen, Asger; Andersen, Stine; Vildbrad, Mads D; Ringgaard, Steffen; Nielsen, Jan M; Nielsen-Kudsk, Jens E

2016-04-01

We investigated if chronic levosimendan treatment can prevent and revert pressure-overload-induced right ventricular hypertrophy and failure in rats. Right ventricular hypertrophy and failure was induced in Wistar rats by pulmonary trunk banding (PTB). The PTB rats were treated with levosimendan (3 mg·kg·d) 3 days before surgery [n = 10, prevention (PREV)], 3 weeks after surgery [n = 10, reversal (REV)] or vehicle (n = 10, VEH). Sham-operated rats received vehicle (n = 16, SHAM). Right ventricular function was evaluated 7 weeks after surgery by echocardiography, magnetic resonance imaging, pressure-volume relations, gross anatomy, and histology. PTB induced right ventricular hypertrophy and compensated heart failure evident by reduced cardiac index (CI) without extra cardiac signs of heart failure. Levosimendan treatment prevented deterioration of right ventricular function measured by CI and right ventricular ejection fraction (RVEF) (CI: VEH vs. PREV 281 ± 17 vs. 362 ± 34 mL·min·kg, P ≤ 0.05, RVEF: VEH vs. PREV 57 ± 2% vs. 68 ± 3%, P ≤ 0.01) to values similar to SHAM (CI: 345 ± 21 mL·min·kg, RVEF: 71 ± 2%). RV contractility was improved in the REV group measured by preload recruitable stroke work (VEH vs. REV 39 ± 3 vs. 66 ± 10 mmHg P ≤ 0.05). Chronic treatment with levosimendan prevents the development of right ventricular failure and improves contractility in established pressure-overload-induced right ventricular failure.

Influence of microalbuminuria on left ventricular geometry and function in hypertensive patients with type 2 diabetes mellitus.

PubMed

Picca, Maurizio; Agozzino, Francesco; Pelosi, Giancarlo

2003-01-01

An increased urinary albumin excretion (UAE) is associated with an augmented risk of cardiovascular disease in diabetic patients and in non-diabetic subjects. Left ventricular hypertrophy has been demonstrated to be a powerful predictor of cardiovascular morbidity and mortality in arterial hypertension and when the ventricular geometry is concentric the relation is even stronger. This echocardiographic and Doppler study was designed to evaluate the influence of microalbuminuria on the left ventricular geometry and function in hypertensive patients with type 2 diabetes melitus. Forty-two patients (16 males, 26 females, mean age 59.6 +/- 6.7 years) with mild-to-moderate essential hypertension and type 2 diabetes mellitus were enrolled in the study. Twenty-one patients had an elevated UAE (group 1) and 21 a normal UAE (group 2). M-mode (under two-dimensional control) and Doppler echocardiography were performed after a 4-week washout period off antihypertensive therapy. The left ventricular mass index was found to be greater than the partition value of 51 g/m2.7 in both groups but was significantly higher (p < 0.001) in group 1. The midwall fractional shortening was significantly lower (p < 0.001) in group 1 in comparison with group 2. The E/A ratio was impaired in both groups but was more significantly reduced (p < 0.02) in group 1. There was a significantly higher prevalence of a left ventricular concentric hypertrophy pattern (19/21 patients, p < 0.001) in group 1. In hypertensive patients with type 2 diabetes mellitus, an elevated UAE is associated with an increased left ventricular mass index, a higher prevalence of a concentric left ventricular hypertrophy pattern, a depressed midwall systolic performance and a markedly impaired diastolic function...

High Serum Phosphorus Level Is Associated with Left Ventricular Diastolic Dysfunction in Peritoneal Dialysis Patients.

PubMed

Ye, Min; Tian, Na; Liu, Yanqiu; Li, Wei; Lin, Hong; Fan, Rui; Li, Cuiling; Liu, Donghong; Yao, Fengjuan

We initiated this study to explore the relationships of serum phosphorus level with left ventricular ultrasound features and diastolic function in peritoneal dialysis (PD) patients. 174 patients with end-stage renal disease (ESRD) receiving PD were enrolled in this retrospective observational study. Conventional echocardiography examination and tissue Doppler imaging (TDI) were performed in each patient. Clinical information and laboratory data were also collected. Analyses of echocardiographic features were performed according to phosphorus quartiles groups. And multivariate regression models were used to determine the association between serum phosphorus and Left ventricular diastolic dysfunction (LVDD). With the increase of serum phosphorus levels, patients on PD showed an increased tissue Doppler-derived E/e' ratio of lateral wall (P < 0.001), indicating a deterioration of left ventricular diastolic function. Steady growths of left atrium and left ventricular diameters as well as increase of left ventricular muscle mass were also observed across the increasing quartiles of phosphorus, while left ventricular ejection fraction remained normal. In a multivariate analysis, the regression coefficient for E/e' ratio in the highest phosphorus quartile was almost threefold higher relative to those in the lowest quartile group. And compared with patients in the lowest phosphorus quartile (<1.34 mmol/L) those in the highest phosphorus quartile (>1.95 mmol/L) had a more than fivefold increased odds of E/e' ratio >15. Our study showed an early impairment of left ventricular diastolic function in peritoneal dialysis patients. High serum phosphorus level was independently associated with greater risk of LVDD in these patients. Whether serum phosphorus will be a useful target for prevention or improvement of LVDD remains to be proved by further studies.

Minimized extracorporeal circulation in coronary artery bypass surgery is equivalent to standard extracorporeal circulation in patients with reduced left ventricular function.

PubMed

Puehler, T; Haneya, A; Philipp, A; Camboni, D; Hirt, S; Zink, W; Lehle, K; Rupprecht, L; Kobuch, R; Diez, C; Schmid, C

2010-06-01

Minimized extracorporeal circulation (MECC) is a promising alternative to standard extracorporeal circulation (ECC) and its use is increasing in routine coronary bypass surgery. We analyzed the clinical outcome of patients with reduced left ventricular function who underwent coronary artery bypass surgery with MECC or with standard ECC. From January 2003 to September 2008, 238 patients with a left ventricular function < 30 % underwent bypass surgery with ECC or MECC. The primary end point of our retrospective observational study was 30-day mortality. Secondary endpoints were the transfusion requirements, as well as intensive care and the in-hospital course. Demographic data, comorbidities and left ventricular function were similar in the study groups. MECC patients had a tendency towards a lower 30-day mortality rate, a better postoperative renal function and reduced ventilation times. Extracorporeal circulation time and postoperative high-dose inotropic support were significantly lower in the MECC group, while the stays in the intensive care unit and in hospital were comparable between the two groups. In our study, age in the ECC group, and previous infarction and New York Heart Association grade IV in the MECC group were preoperative risk factors associated with a higher mortality. Coronary bypass surgery using MECC is feasible and safe for patients with severely impaired left ventricular function. It is a promising alternative to ECC with a low mortality rate and a more favorable postoperative course.

Cardiac myofibrillar contractile properties during the progression from hypertension to decompensated heart failure.

PubMed

Hanft, Laurin M; Emter, Craig A; McDonald, Kerry S

2017-07-01

Heart failure arises, in part, from a constellation of changes in cardiac myocytes including remodeling, energetics, Ca 2+ handling, and myofibrillar function. However, little is known about the changes in myofibrillar contractile properties during the progression from hypertension to decompensated heart failure. The aim of the present study was to provide a comprehensive assessment of myofibrillar functional properties from health to heart disease. A rodent model of uncontrolled hypertension was used to test the hypothesis that myocytes in compensated hearts exhibit increased force, higher rates of force development, faster loaded shortening, and greater power output; however, with progression to overt heart failure, we predicted marked depression in these contractile properties. We assessed contractile properties in skinned cardiac myocyte preparations from left ventricles of Wistar-Kyoto control rats and spontaneous hypertensive heart failure (SHHF) rats at ~3, ~12, and >20 mo of age to evaluate the time course of myofilament properties associated with normal aging processes compared with myofilaments from rats with a predisposition to heart failure. In control rats, the myofilament contractile properties were virtually unchanged throughout the aging process. Conversely, in SHHF rats, the rate of force development, loaded shortening velocity, and power all increased at ~12 mo and then significantly fell at the >20-mo time point, which coincided with a decrease in left ventricular fractional shortening. Furthermore, these changes occurred independent of changes in β-myosin heavy chain but were associated with depressed phosphorylation of myofibrillar proteins, and the fall in loaded shortening and peak power output corresponded with the onset of clinical signs of heart failure. NEW & NOTEWORTHY This novel study systematically examined the power-generating capacity of cardiac myofilaments during the progression from hypertension to heart disease. Previously undiscovered changes in myofibrillar power output were found and were associated with alterations in myofilament proteins, providing potential new targets to exploit for improved ventricular pump function in heart failure. Copyright © 2017 the American Physiological Society.

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance

PubMed Central

van Geuns, Robert‐Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J.G.M.

2017-01-01

Abstract Aims Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast‐enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. Methods and results We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast‐enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non‐invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P < 0.001). Right ventricular enhancement correlated with systolic ventricular dysfunction (P < 0.001), hypertrophy (P = 0.001), and dilation (P < 0.001). Conclusions Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. PMID:29154434

Left bundle branch block, an old-new entity.

PubMed

Breithardt, Günter; Breithardt, Ole-Alexander

2012-04-01

Left bundle branch block (LBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction, but also in comparison to right bundle branch block which is generally considered to be benign in the absence of an underlying cardiac disorder like congenital heart disease. LBBB may be the first manifestation of a more diffuse myocardial disease. The typical surface ECG feature of LBBB is a prolongation of QRS above 0.11 s in combination with a delay of the intrinsic deflection in leads V5 and V6 of more than 60 ms and no septal q waves in leads I, V5, and V6 due to the abnormal septal activation from right to left. LBBB may induce abnormalities in left ventricular performance due to abnormal asynchronous contraction patterns which can be compensated by biventricular pacing (resynchronization therapy). Asynchronous electrical activation of the ventricles causes regional differences in workload which may lead to asymmetric hypertrophy and left ventricular dilatation, especially due to increased wall mass in late-activated regions, which may aggravate preexisting left ventricular pumping performance or even induce it. Of special interest are patients with LBBB and normal left ventricular dimensions and normal ejection fraction at rest but who may present with an abnormal increase in pulmonary artery pressure during exercise, production of lactate during high-rate pacing, signs of ischemia on myocardial scintigrams (but no coronary artery narrowing), and abnormal ultrastructural findings on myocardial biopsy. For this entity, the term latent cardiomyopathy had been suggested previously.

Impact of chronic obstructive pulmonary diseases on left ventricular diastolic function in hospitalized elderly patients

PubMed Central

Huang, Ying-Shuo; Feng, Ying-Chao; Zhang, Jian; Bai, Li; Huang, Wei; Li, Min; Sun, Ying

2015-01-01

Objective To evaluate the impact of chronic obstructive pulmonary disease (COPD) on left ventricular (LV) diastolic function in hospitalized elderly patients. Methods This was a case–control observational study of 148 consecutive hospitalized elderly patients (≥65 years old): 73 subjects without COPD as controls and 75 patients with COPD. Mild-to-moderate COPD was defined as stages 1 and 2, while severe and very severe COPD was defined as stages 3 and 4, according to the Global Initiative for Chronic Obstructive Lung Disease guidelines. Clinical characteristics and echocardiographic parameters were analyzed and compared. Results Compared with the control group, patients with COPD had a higher frequency of LV diastolic dysfunction and heart failure with preserved ejection fraction. Smoking frequency, frequency of cerebrovascular diseases and diabetes, and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were higher in the COPD group (all P<0.05). COPD patients showed more abnormalities in diastolic function (E/e′: 11.51±2.50 vs 10.42±3.25, P=0.047), but no differences in systolic function and right ventricular function (all P>0.05). Patients with severe/very severe COPD showed no differences in LV diastolic function compared to patients with mild/moderate COPD (P>0.05), but serum NT-proBNP levels were higher in severe/very severe COPD (P<0.05). Conclusion Results suggest that early-stage COPD may have an impact on the LV diastolic function. Severe COPD mainly affected right ventricular function. In hospitalized elderly patients with COPD, LV diastolic dysfunction should be taken into account together with right ventricular function. PMID:25565790

Effects of liraglutide on left ventricular function in patients with non-ST-segment elevation myocardial infarction.

PubMed

Chen, Wei-Ren; Shen, Xue-Qin; Zhang, Ying; Chen, Yun-Dai; Hu, Shun-Ying; Qian, Geng; Wang, Jing; Yang, Jun-Jie; Wang, Zhi-Feng; Tian, Feng

2016-06-01

The influence of glucagon-like peptide-1 has been studied in several studies in patients with acute myocardial infarction, but not in patients with non-ST-segment elevation myocardial infarction (NSTEMI). We planned to evaluate the effects of liraglutide on left ventricular function in patients with NSTEMI. A total of 90 patients were randomized 1:1 to receive either liraglutide (0.6 mg for 2 days, 1.2 mg for 2 days, followed by 1.8 mg for 3 days) or placebo for 7 days. Eighty-three patients completed the trial. Transthoracic echocardiography was used to assess left ventricular function. At 3 months, the primary endpoint, the difference in the change in left ventricular ejection fraction between the two groups was +4.7 % (liraglutide vs. placebo 95 % CI +0.7 to +9.2 % P = 0.009) under intention-to-treat analysis. The difference in decrease in serum glycosylated hemoglobin levels was -0.2 % (liraglutide vs. placebo 95 % CI -0.1 to -0.3 %; P < 0.001). Inflammation and oxidative stress improved significantly in the liraglutide group compared to the placebo group. Liraglutide could improve left ventricular function in patients with NSTEMI, making it a potential adjuvant therapy for NSTEMI.

Left ventricular function abnormalities as a manifestation of silent myocardial ischemia.

PubMed

Lambert, C R; Conti, C R; Pepine, C J

1986-11-01

A large body of evidence exists indicating that left ventricular dysfunction is a common occurrence in patients with severe coronary artery disease and represents silent or asymptomatic myocardial ischemia. Such dysfunction probably occurs early in the time course of every ischemic episode in patients with coronary artery disease whether symptoms are eventually manifested or not. The pathophysiology of silent versus symptomatic left ventricular dysfunction due to ischemia appears to be identical. Silent ischemia-related left ventricular dysfunction can be documented during spontaneous or stress-induced perturbations in the myocardial oxygen supply/demand ratio. It also may be detected by nitroglycerin-induced improvement in ventricular function or by salutary changes in wall motion following revascularization. Silent left ventricular dysfunction is a very early occurrence during ischemia and precedes electrocardiographic abnormalities. In this light, its existence should always be kept in mind when dealing with patients with ischemic heart disease. It can be hypothesized that because silent ischemia appears to be identical to ischemia with symptoms in a pathophysiologic sense, prognosis and treatment in both cases should be the same.

Intraprocedural left ventricular free wall rupture diagnosed by left ventriculogram in a patient with infero-posterior myocardial infarction and severe aortic stenosis.

PubMed

Konishi, Takao; Funayama, Naohiro; Yamamoto, Tadashi; Nishihara, Hiroshi; Hotta, Daisuke; Kikuchi, Kenjiro; Yokoyama, Hideo; Ohori, Katsumi

2016-06-06

Left ventricular wall rupture remains a major lethal complication of acute myocardial infarction and hypertension is a well-known predisposing factor of cardiac rupture after myocardial infarction. An 87-year-old man was admitted to our hospital, diagnosed as acute myocardial infarction (AMI). The echocardiogram showed 0.67-cm(2) aortic valve, consistent with severe aortic stenosis (AS). A coronary angiography showed a chronic occlusion of the proximal left circumflex artery and a 99 % stenosis and thrombus in the mid right coronary artery. During percutaneous angioplasty of the latter, transient hypotension and bradycardia developed at the time of balloon inflation, and low doses of noradrenaline and etilefrine were intravenously administered as needed. The patient suddenly lost consciousness and developed electro-mechanical dissociation. Cardio-pulmonary resuscitation followed by insertion of an intra-aortic balloon pump (IABP) and percutaneous cardiopulmonary support were initiated. The echocardiogram revealed moderate pericardial effusion, though the site of free wall rupture was not distinctly visible. A left ventriculogram clearly showed an infero-posterior apical wall rupture. Surgical treatment was withheld because of the interim development of brain death. In this patient, who presented with severe AS, the administration of catecholamine to stabilize the blood pressure probably increased the intraventricular pressures considerably despite apparently normal measurements of the central aortic pressure. IABP, temporary pacemaker, or both are recommended instead of intravenous catecholamines for patients with AMI complicated with significant AS to stabilize hemodynamic function during angioplasty.

Left Ventricular Dysfunction and Dilated Cardiomyopathy in Infants and Children with Wolff-Parkinson-White Syndrome in the Absence of Tachyarrhythmias

PubMed Central

2012-01-01

Left ventricular (LV) dysfunction and dilated cardiomyopathy (DCM) are rarely attributable to sustained or incessant tachyarrhythmias in infants and children with Wolff-Parkinson-White (WPW) syndrome. However, several recent reports suggested that significant LV dysfunction may develop in WPW syndrome in the absence of tachyarrhythmias. It is assumed that an asynchronous ventricular activation over the accessory pathway, especially right-sided, induces septal wall motion abnormalities, ventricular remodeling and ventricular dysfunction. The prognosis of DCM associated with asymptomatic WPW is excellent. Loss of ventricular pre-excitation results in mechanical resynchronization and reverse remodeling where LV function recovers completely. The reversible nature of LV dysfunction after loss of ventricular pre-excitation supports the causal relationship between LV dysfunction and ventricular pre-excitation. This review summarizes recent clinical and electrophysiological evidence for development of LV dysfunction or DCM in asymptomatic WPW syndrome, and discusses the underlying pathophysiological mechanism. PMID:23323117

Point-of-Care Ultrasonography to Assess Portal Vein Pulsatility and the Effect of Inhaled Milrinone and Epoprostenol in Severe Right Ventricular Failure: A Report of 2 Cases.

PubMed

Tremblay, Jan-Alexis; Beaubien-Souligny, William; Elmi-Sarabi, Mahsa; Desjardins, Georges; Denault, André Y

2017-10-15

This article describes 2 patients with severe acute right ventricular failure causing circulatory shock. Portal vein pulsatility assessed by bedside ultrasonography suggested clinically relevant venous congestion. Management included cardiac preload reduction and combined inhalation of milrinone and epoprostenol to reduce right ventricular afterload. Portal vein ultrasonography may be useful in assessing right ventricular function in the acutely ill patient.

Bridging the gap: Hybrid cardiac echo in the critically ill.

PubMed

Glaser, Jacob J; Cardarelli, Cassandra; Galvagno, Samuel; Scalea, Thomas M; Murthi, Sarah B

2016-11-01

Point-of-care ultrasound often includes cardiac ultrasound. It is commonly used to evaluate cardiac function in critically ill patients but lacks the specific quantitative anatomic assessment afforded by standard transthoracic echocardiography (TTE). We developed the Focused Rapid Echocardiographic Examination (FREE), a hybrid between a cardiac ultrasound and TTE that places an emphasis on cardiac function rather than anatomy. We hypothesized that data obtained from FREE correlate well with TTE while providing actionable information for clinical decision making. FREE examinations evaluating cardiac function (left ventricular ejection fraction), diastolic dysfunction (including early mitral Doppler flow [E] and early mitral tissue Doppler [E']), right ventricular function, cardiac output, preload (left ventricular internal dimension end diastole), stroke volume, stroke volume variation, inferior vena cava diameter, and inferior vena cava collapse were performed. Patients who underwent both a TTE and FREE on the same day were identified as the cohort, and quantitative measurements were compared. Correlation analyses were performed to assess levels of agreement. A total of 462 FREE examinations were performed, in which 69 patients had both a FREE and TTE. FREE ejection fraction was strongly correlated with TTE (r = 0.89, 95% confidence interval). Left ventricular outflow tract, left ventricular internal dimension end diastole, E, and lateral E' derived from FREE were also strongly correlated with TTE measurements (r = 0.83, r = 0.94, r = 0.77, and r = 0.88, respectively). In 82% of the patients, right ventricular function for FREE was the same as that reported for TTE; pericardial effusion was detected on both examinations in 94% of the cases. No significant valvular anatomy was missed with the FREE examination. Functionally rather than anatomically based hybrid ultrasound examinations, like the FREE, facilitate decision making for critically ill patients. The FREE's functional assessment correlates well with TTE measurements and may be of significant clinical value in critically ill patients, especially when used in remote operating environments where resources are limited. Diagnostic test, level III.