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1

Cardiac Output Assessed by Invasive and Minimally Invasive Techniques  

PubMed Central

Cardiac output (CO) measurement has long been considered essential to the assessment and guidance of therapeutic decisions in critically ill patients and for patients undergoing certain high-risk surgeries. Despite controversies, complications and inherent errors in measurement, pulmonary artery catheter (PAC) continuous and intermittent bolus techniques of CO measurement continue to be the gold standard. Newer techniques provide less invasive alternatives; however, currently available monitors are unable to provide central circulation pressures or true mixed venous saturations. Esophageal Doppler and pulse contour monitors can predict fluid responsiveness and have been shown to decrease postoperative morbidity. Many minimally invasive techniques continue to suffer from decreased accuracy and reliability under periods of hemodynamic instability, and so few have reached the level of interchangeability with the PAC. PMID:21776254

Lee, Allison J.; Cohn, Jennifer Hochman; Ranasinghe, J. Sudharma

2011-01-01

2

In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images  

NASA Astrophysics Data System (ADS)

Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was validated quantitatively by comparing it with the CO values measured from the volume flow in the pulmonary artery. Relative bias varied between 0 and -17%, where the nominal accuracy of the flow meter is in the order of 10%. Assuming the CO measurements from the flow probe as a gold standard, excellent correlation (r = 0.99) was observed with the CO estimates obtained from image segmentation.

Nillesen, M. M.; Lopata, R. G. P.; de Boode, W. P.; Gerrits, I. H.; Huisman, H. J.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

2009-04-01

3

Assessment of cardiac output with transpulmonary thermodilution during exercise in humans.  

PubMed

The accuracy and reproducibility of transpulmonary thermodilution (TPTd) to assess cardiac output (Q?) in exercising men was determined using indocyanine green (ICG) dilution as a reference method. TPTd has been utilized for the assessment of Q? and preload indexes of global end-diastolic volume and intrathoracic blood volume, as well as extravascular lung water (EVLW) in resting humans. It remains unknown if this technique is also accurate and reproducible during exercise. Sixteen healthy men underwent catheterization of the right femoral vein (for iced saline injection), an antecubital vein (ICG injection), and femoral artery (thermistor) to determine their Q? by TPTd and ICG concentration during incremental one- and two-legged pedaling on a cycle ergometer and combined arm cranking with leg pedaling to exhaustion. There was a close relationship between TPTd-Q? and ICG-Q? (r = 0.95, n = 151, standard error of the estimate: 1.452 l/min, P < 0.001; mean difference of 0.06 l/min; limits of agreement -2.98 to 2.86 l/min), and TPTd-Q? and ICG-Q? increased linearly with oxygen uptake with similar intercepts and slopes. Both methods had mean coefficients of variation close to 5% for Q?, global end-diastolic volume, and intrathoracic blood volume. The mean coefficient of variation of EVLW, assessed with both indicators (ICG and thermal) was 17% and was sensitive enough to detect a reduction in EVLW of 107 ml when changing from resting supine to upright exercise. In summary, TPTd with bolus injection into the femoral vein is an accurate and reproducible method to assess Q? during exercise in humans. PMID:25359719

Calbet, José A L; Boushel, Robert

2015-01-01

4

Reliability of peak and maximal cardiac output assessed using thoracic bioimpedance in children  

Microsoft Academic Search

The purpose of this study was to evaluate the reliability of a thoracic electrical bioimpedance based device (PhysioFlow) for the determination of cardiac output and stroke volume during exercise at peak oxygen uptake (peak \\u000a in children. The reliability of peak \\u000a is also reported. Eleven boys and nine girls aged 10–11 years completed a cycle ergometer test to voluntary exhaustion on three

Joanne Welsman; Katie Bywater; Colin Farr; Deborah Welford; Neil Armstrong

2005-01-01

5

The Determinants of Cardiac Output  

NSDL National Science Digital Library

Part of the Gross Physiology of the Cardiovascular System site, this 22-minute video presentation explains fundamental but often misunderstood concepts about the determinants of cardiac output, using Dr. Anderson's hydraulic model of the cardiovascular system. It is a useful summary and overview of the concepts presented in greater detail in the online text. A transcript of the video presentation is available.

Anderson, Robert M.

6

Assessment of the effect of vasodilators on the distribution of cardiac output by whole-body Thallium imaging  

SciTech Connect

Vasodilator therapy (tx) of congestive heart failure (CHF) has been shown to be effective in increasing cardiac output (CO) and lowering vascular resistance. Unfortunately, these hemodynamic effects are not usually accompanied by improved peripheral circulation of exercise capacity. To assess the effect of a new vasodilator, Cl-914, on the redistribution of CO to the peripheral circulation, the authors performed testing whole-body thallium scanning (WB-Th) on 6 patients (pts) with severe CHF. Immediately following i.v. injection of 1.5 mCi Th-201, WB scanning was performed from anterior and posterior views. Regions of interest were defined for the peripheral (P) muscles (legs and arms), central torso (C), and splanchnic bed (S). The geometric mean of activity in these regions was calculated from both views. Each pt was studied before tx and again, after 1 week on tx. Invasive measurements revealed that all pts had significant improvements in resting cardiac output (mean increase 49%) and vascular resistance (mean decrease 30%). Unlike other vasodilators, all CI-914 pts had a significant improvement in treadmill exercise capacity (mean increase 54%). WB-Th revealed a significant shift in CO to the peripheral circulation with P:C increased 33.2% (rho= .001) and P:S increased 29% (rho=.01). Vasoactive drugs may significantly alter the relative distribution of cardiac output. WB-Th scanning provides a simple quantitative means of following such changes.

Juni, J.E.; Wallis, J.; Diltz, E.; Nicholas, J.; Lahti, D.; Pitt, B.

1985-05-01

7

Mathematics and the Heart: Understanding Cardiac Output  

ERIC Educational Resources Information Center

This paper illustrates a biological application of the concepts of relative change and area under a curve, from mathematics. We study two biological measures "relative change in cardiac output" and "cardiac output", which are predictors of heart blockages and other related ailments. Cardiac output refers to the quantity of…

Champanerkar, Jyoti

2013-01-01

8

Bioimpedance and bioreactance methods for monitoring cardiac output.  

PubMed

Noninvasive continuous cardiac output monitoring may have wide clinical applications in anaesthesiology, emergency care and cardiology. It can improve outcomes, establish diagnosis, guide therapy and help risk stratification. The present article describes the theory behind the two noninvasive continuous monitoring methods for cardiac output assessment such as bioimpedance and bioreactance. The review discusses the advantages and disadvantages of these methods and highlights the recent method comparison studies. The use of bioimpedance and bioreactance to estimate cardiac output under haemodynamic challenges is also discussed. In particular, the article focuses on performance of the two methods in the assessment of fluid responsiveness using passive leg raising test and cardiac output response to exercise stress testing. PMID:25480768

Jakovljevic, Djordje G; Trenell, Michael I; MacGowan, Guy A

2014-12-01

9

Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments  

PubMed Central

Background and purpose The Electro Sensor Complex (ESC) is software that combines three devices using bioelectrical impedance, galvanic skin response, and spectrophotometry: (1) ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL) to assess body composition, (2) EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology) to predict autonomic nervous system activity, and (3) ES Oxi (Electro Sensor Oxi; LD Technology) to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA), EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA). Patients and methods The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output. Results We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001) with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001) with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R2 = 0.56, P = 0.03). For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001), after the first exercise stage (r = 0.79, P < 0.001), and after the second exercise stage (r = 0.86, P < 0.001). Absolute agreement was found at baseline and after both bouts of exercise; ES Oxi overestimated baseline and stage 1 exercise cardiac output by 0.3 L/minute and 0.1 L/minute, respectively, but exactly estimated stage 2 exercise cardiac output. Conclusion ES-BC and ES Oxi accurately assessed body composition and cardiac output compared to standardized instruments, whereas EIS-GS showed marginal predictive ability for autonomic nervous system activity. The ESC software managing the three devices would be useful to help detect complications related to metabolic syndrome, diabetes, and cardiovascular disease and to noninvasively and rapidly manage treatment follow-up. PMID:22915943

Lewis, John E; Tannenbaum, Stacey L; Gao, Jinrun; Melillo, Angelica B; Long, Evan G; Alonso, Yaima; Konefal, Janet; Woolger, Judi M; Leonard, Susanna; Singh, Prabjot K; Chen, Lawrence; Tiozzo, Eduard

2011-01-01

10

RETRACTED ARTICLE: Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution  

Microsoft Academic Search

Objective  To compare noninvasive cardiac output (CO)measurement obtained with a new thoracic electrical bioimpedance (TEB) device, using\\u000a a proprietary modification of the impedance equation, with invasive measurement obtained via pulmonary artery thermodilution.\\u000a \\u000a \\u000a \\u000a \\u000a Design  Prospective, observational study.\\u000a \\u000a \\u000a \\u000a Setting  Surgical intensive care unit (ICU) of a university-affiliated community hospital.\\u000a \\u000a \\u000a \\u000a Patients and participants  Seventy-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement.\\u000a \\u000a \\u000a \\u000a Interventions  None.\\u000a \\u000a \\u000a \\u000a Measurements and results  Simultaneous

Stefan Suttner; Thilo Schöllhorn; Joachim Boldt; Jochen Mayer; Kerstin D. Röhm; Katrin Lang; Swen N. Piper

2006-01-01

11

Evaluation of noninvasive cardiac output methods during exercise  

NASA Technical Reports Server (NTRS)

Noninvasive techniques to estimate cardiac output (Qc) will be used during future space flight. This retrospective literature survey compared the Qc techniques of carbon dioxide rebreathing (CO2-R), CO2 single breath (CO2-S), Doppler (DOP), impedance (IM), and inert gas (IG: acetylene or nitrous oxide) to direct (DIR) assessments measured at rest and during exercise.

Moore, Alan D.; Barrows, Linda H.; Rashid, Michael; Siconolfi, Steven F.

1992-01-01

12

Methods and apparatus for determining cardiac output  

NASA Technical Reports Server (NTRS)

The present invention provides methods and apparatus for determining a dynamical property of the systemic or pulmonary arterial tree using long time scale information, i.e., information obtained from measurements over time scales greater than a single cardiac cycle. In one aspect, the invention provides a method and apparatus for monitoring cardiac output (CO) from a single blood pressure signal measurement obtained at any site in the systemic or pulmonary arterial tree or from any related measurement including, for example, fingertip photoplethysmography.According to the method the time constant of the arterial tree, defined to be the product of the total peripheral resistance (TPR) and the nearly constant arterial compliance, is determined by analyzing the long time scale variations (greater than a single cardiac cycle) in any of these blood pressure signals. Then, according to Ohm's law, a value proportional to CO may be determined from the ratio of the blood pressure signal to the estimated time constant. The proportional CO values derived from this method may be calibrated to absolute CO, if desired, with a single, absolute measure of CO (e.g., thermodilution). The present invention may be applied to invasive radial arterial blood pressure or pulmonary arterial blood pressure signals which are routinely measured in intensive care units and surgical suites or to noninvasively measured peripheral arterial blood pressure signals or related noninvasively measured signals in order to facilitate the clinical monitoring of CO as well as TPR.

Cohen, Richard J. (Inventor); Mukkamala, Ramakrishna (Inventor); Sherman, Derin A. (Inventor)

2010-01-01

13

Cardiac Risk Assessment  

MedlinePLUS

... helpful? Formal name: Cardiac Risk Assessment Related tests: Lipid Profile , VLDL Cholesterol , hs-CRP , Lp(a) Overview | ... on Coronary artery disease: Tests and diagnosis .) The lipid profile is the most important blood test for ...

14

Predictors of low cardiac output syndrome after coronary artery bypass  

Microsoft Academic Search

The purpose of this study was to identify patients at risk for the development of low cardiac output syndrome after coronary artery bypass. Low cardiac output syndrome was defined as the need for postoperative intraaortic balloon pump or inotropic support for longer than 30 minutes in the intensive care unit to maintain the systolic blood pressure greater than 90 mm

Vivek Rao; Joan Ivanov; Richard D. Weisel; John S. Ikonomidis; George T. Christakis; Tirone E. David

1996-01-01

15

[Echocardiography in emergency admissions. Recognition of cardiac low-output failure].  

PubMed

Detection of acute cardiac dysfunction and differential diagnosis of low cardiac output syndrome is challenging for emergency physicians. For the critical ill patient it is essential to rapidly identify the underlying disease to initiate the correct therapy and optimize patient outcome. Echocardiography is the diagnostic tool of choice for the evaluation of low cardiac output states. In the setting of the emergency department the use of focused echocardiography instead of detailed echocardiographic studies of cardiologists is appropriate and should be provided for emergency care. The differentiation in preserved versus reduced left ventricular ejection fraction as a first assessment is helpful, particularly for physicians not well trained in echocardiography. The structured and focused approach to evaluate or exclude differential diagnoses of cardiac dysfunction is the key for optimal management of acute and critically ill patients with low cardiac output. PMID:23052991

Schmidt, J; Maier, A; Christ, M

2012-10-01

16

Evaluation of heavy water for indicator dilution cardiac output measurement  

SciTech Connect

We evaluated deuterium oxide (D2O) as a tracer for cardiac output measurements. Cardiac output measurements made by thermodilution were compared with those made by indicator dilution with D2O and indocyanine green as tracers. Five triplicate measurements for each method were made at intervals of 30 minutes in each of 9 anesthetized, mechanically ventilated goats. Cardiac output ranged between 0.68 and 3.79 L/min. The 45 data points yielded a correlation coefficient of 0.948 for the comparison of D2O indicator dilution cardiac output measurements with thermodilution measurements and a linear regression slope of 1.046. D2O indicator dilution measurements were biased by -0.11 +/- 0.22 L/min compared with thermodilution measurements and had a standard deviation of +/- 0.12 L/min for triplicate measurements. Hematocrits ranging between 20 and 50 vol% had no effect on optical density for D2O. D2O is more stable than indocyanine green and approximately one-tenth the price (40 cents per injection compared with $4). The basic instrumentation cost of approximately $9,000 is an additional initial expense, but provides the ability to perform pulmonary extravascular water measurements with a double-indicator dilution technique. D2O has potential as a tracer for the clinical determination of indicator dilution cardiac output measurements and pulmonary extravascular water measurements.

Schreiner, M.S.; Leksell, L.G.; Neufeld, G.R. (Univ. of Pennsylvania School of Medicine, Philadelphia (USA))

1989-10-01

17

Red cell volume and cardiac output in anaemic preterm infants  

Microsoft Academic Search

To test the hypothesis that haemoglobin concentration is a poor predictor of benefit from transfusion in preterm infants, and that red cell volume is the most important indicator of anaemia, 24 preterm infants receiving red cell transfusions had red cell volume, haemoglobin concentration, and cardiac output measured before and after transfusion. Red cell volume was measured either using dilution of

I Hudson; A Cooke; B Holland; A Houston; J G Jones; T Turner; C A Wardrop

1990-01-01

18

Cardiac output and stroke volume estimation using a hybrid of three Windkessel models  

Microsoft Academic Search

Cardiac output (CO) and stroke volume (SV) are the key hemodynamic parameters to be monitored and assessed in ambulatory and critically ill patients. The purpose of this study was to introduce and validate a new algorithm to continuously estimate, within a proportionality constant, CO and SV by means of mathematical analysis of peripheral arterial blood pressure (ABP) waveforms. The algorithm

Tatsuya Arai; Kichang Lee; Richard J. Cohen

2010-01-01

19

Noninvasive Determination of Cardiac Output by the Inert-Gas-Rebreathing Method – Comparison with Cardiovascular Magnetic Resonance Imaging  

Microsoft Academic Search

Background: An easy, noninvasive and accurate technique for measuring cardiac output (CO) would be desirable for the diagnosis and therapy of cardiac diseases. Innocor, a novel inert-gas-rebreathing (IGR) system, has shown promising results in smaller studies. An extensive evaluation in a larger, less homogeneous patient collective is lacking. Methods: We prospectively assessed the accuracy and reproducibility of CO measurements obtained

Joachim Saur; Stephan Fluechter; Frederik Trinkmann; Theano Papavassiliu; Stefan Schoenberg; Joerg Weissmann; Dariusch Haghi; Martin Borggrefe; Jens J. Kaden

2009-01-01

20

Measurement of cardiac output from dynamic pulmonary circulation time CT  

SciTech Connect

Purpose: To introduce a method of estimating cardiac output from the dynamic pulmonary circulation time CT that is primarily used to determine the optimal time window of CT pulmonary angiography (CTPA). Methods: Dynamic pulmonary circulation time CT series, acquired for eight patients, were retrospectively analyzed. The dynamic CT series was acquired, prior to the main CTPA, in cine mode (1 frame/s) for a single slice at the level of the main pulmonary artery covering the cross sections of ascending aorta (AA) and descending aorta (DA) during the infusion of iodinated contrast. The time series of contrast changes obtained for DA, which is the downstream of AA, was assumed to be related to the time series for AA by the convolution with a delay function. The delay time constant in the delay function, representing the average time interval between the cross sections of AA and DA, was determined by least square error fitting between the convoluted AA time series and the DA time series. The cardiac output was then calculated by dividing the volume of the aortic arch between the cross sections of AA and DA (estimated from the single slice CT image) by the average time interval, and multiplying the result by a correction factor. Results: The mean cardiac output value for the six patients was 5.11 (l/min) (with a standard deviation of 1.57 l/min), which is in good agreement with the literature value; the data for the other two patients were too noisy for processing. Conclusions: The dynamic single-slice pulmonary circulation time CT series also can be used to estimate cardiac output.

Yee, Seonghwan, E-mail: Seonghwan.Yee@Beaumont.edu [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States)] [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States); Scalzetti, Ernest M. [Department of Radiology, SUNY Upstate Medical University, Syracuse, New York 13210 (United States)] [Department of Radiology, SUNY Upstate Medical University, Syracuse, New York 13210 (United States)

2014-06-15

21

Transthoracic electrical bioimpedance versus thermodilution technique for cardiac output measurement during mechanical ventilation  

Microsoft Academic Search

To study the possible influence of mechanical ventilation on the accurracy of thoracic electrical bioimpedance (TEI) in the measurement of cardiac output, we determined cardiac output concurrently by TEI using Kubicek's equation and by thermodilution in 8 acutely ill patients who were mechanically ventilated (assist\\/control mode) but who had no underlying respiratory failure. Cardiac outputs were lower with TEI than

J. C. Preiser; A. Daper; J.-N. Parquier; B. Contempré; J.-L. Vincent

1989-01-01

22

Non-invasive determination of cardiac output by Doppler echocardiography and electrical bioimpedance  

Microsoft Academic Search

Cardiac output measured by thermodilution in 25 patients within 24 hours of acute myocardial infarction was compared with cardiac output measured by Doppler echocardiography (24 patients) and electrical bioimpedance (25 patients). The mean (range) cardiac outputs measured by Doppler (4.03 (2.2-6.0) 1\\/min) and electrical bioimpedance (3.79 (1.1-6.2) 1\\/min) were similar to the mean thermodilution value (3.95 (2.1-6.2) 1\\/min). Both non-invasive

D B Northridge; I N Findlay; J Wilson; E Henderson; H J Dargie

1990-01-01

23

Physiologic and Clinical Principles behind Noninvasive Resuscitation Techniques and Cardiac Output Monitoring  

PubMed Central

Clinical assessment and vital signs are poor predictors of the overall hemodynamic state. Optimal measurement of the response to fluid resuscitation and hemodynamics has previously required invasive measurement with radial and pulmonary artery catheterization. Newer noninvasive resuscitation technology offers the hope of more accurately and safely monitoring a broader range of critically ill patients while using fewer resources. Fluid responsiveness, the cardiac response to volume loading, represents a dynamic method of improving upon the assessment of preload when compared to static measures like central venous pressure. Multiple new hemodynamic monitors now exist that can noninvasively report cardiac output and oxygen delivery in a continuous manner. Proper assessment of the potential future role of these techniques in resuscitation requires understanding the underlying physiologic and clinical principles, reviewing the most recent literature examining their clinical validity, and evaluating their respective advantages and limitations. PMID:21860802

Napoli, Anthony M.

2012-01-01

24

Maximal Cardiac Output Determines 6 Minutes Walking Distance in Pulmonary Hypertension  

PubMed Central

Purpose The 6 minutes walk test (6MWT) is often shown to be the best predictor of mortality in pulmonary hypertension (PH) probably because it challenges the failing heart to deliver adequate cardiac output. We hypothesised that the 6MWT elicits maximal cardiac output as measured during a maximal cardiopulmonary exercise testing (CPET). Methods 18 patients with chronic thromboembolic pulmonary hypertension (n?=?12) or pulmonary arterial hypertension (n?=?6) and 10 healthy subjects performed a 6MWT and CPET with measurements of cardiac output (non invasive rebreathing device) before and directly after exercise. Heart rate was measured during 6MWT with a cardiofrequence meter. Results Cardiac output and heart rate measured at the end of the 6MWT were linearly related to 6MW distance (mean±SD: 490±87 m). Patients with a high NT-pro-BNP achieve a maximum cardiac output during the 6MWT, while in normal subjects and in patients with a low-normal NT-proBNP, cardiac output at the end of a 6MWT was lower than achieved at maximum exercise during a CPET. In both cases, heart rate is the major determinant of exercise-induced increase in cardiac output. However, stroke volume increased during CPET in healthy subjects, not in PH patients. Conclusion Maximal cardiac output is elicited by 6MWT in PH patients with failing right ventricle. Cardiac output increase is dependent on chronotropic response in patients with PH. PMID:24647561

Deboeck, Gaël; Taboada, Dolores; Hagan, Guy; Treacy, Carmen; Page, Kathy; Sheares, Karen; Naeije, Robert; Pepke-Zaba, Joanna

2014-01-01

25

Regional blood flow distribution in dog during induced hypotension and low cardiac output. Spontaneous breathing versus artificial ventilation.  

PubMed Central

Respiratory muscle blood flow and organ blood flow was studied in two groups of dogs with radioactively labeled microspheres to assess the influence of the working respiratory muscles on the regional distribution of blood flow when arterial pressure and cardiac output were lowered by pericardial tamponade. In one group (n = 6), the dogs were paralyzed and mechanically ventilated (Mv), while in the other (n = 6), they were left to breathe spontaneously (Sb). Cardiac output fell to 30% of control values during tamponade in both groups and was maintained constant. None of the dogs was hypoxic. Ventilation in the Sb group peaked after 50 min of hypotension, but remained unchanged in the Mv group. Duplicate measurements of blood flow were made during a control period and after 50 min of tamponade (corresponding to the peak ventilation in Sb). Blood flow to the respiratory muscles increased significantly (P less than 0.001) during tamponade in Sb (diaphragmatic flow increased to 361% of control values), while it decreased in Mv. Although the arterial blood pressure and cardiac output were comparable in the two groups, blood flow distribution during tamponade was different. In Sb, the respiratory muscles received 21% of the cardiac output, compared with only 3% in the Mv group. Thus, by muscle paralysis and Mv, a large fraction of the cardiac output used by the working respiratory muscles can be made available for perfusion of other organs during low cardiac output state: blood flows to the liver, brain, and quadriceps muscles were significantly higher during tamponade in the Mv group compared with the Sb group. Similarly, blood lactate at all times after the induction of low cardiac output and hypotension was significantly lower in the Mv animals (P less than 0.005). PMID:6886012

Viires, N; Sillye, G; Aubier, M; Rassidakis, A; Roussos, C

1983-01-01

26

Chronic measurement of cardiac output in conscious mice.  

PubMed

We describe the feasibility of chronic measurement of cardiac output (CO) in conscious mice. With the use of gas anesthesia, mice >30 g body wt were instrumented either with transit-time flow probes or electromagnetic probes placed on the ascending aorta. Ascending aortic flow values were recorded 6-16 days after surgery when probes had fully grown in. In the first set of experiments, while mice were under ketamine-xylazine anesthesia, estimates of stroke volume (SV) obtained by the transit-time technique were compared with those simultaneously obtained by echocardiography. Transit-time values of SV were similar to those obtained by echocardiography. The average difference +/- SD between the methods was 2 +/- 7 microl. In the second set of studies, transit-time values of CO were compared with those obtained by the electromagnetic flow probes. In conscious resting conditions, estimates +/- SD) of cardiac index (CI) obtained by the transit-time and electromagnetic flow probes were 484 +/- 119 and 531 +/- 103 ml x min(-1) x kg body wt(-1), respectively. Transit-time flow probes were also implanted in mice with a myocardial infarction (MI) induced by ligation of a coronary artery 3 wk before probe implantation. In these MI mice (n = 7), average (+/- SD) resting and stimulated (by volume loading) values of CO were significantly lower than in noninfarcted mice (n = 15) (resting CO 16 +/- 3 vs. 20 +/- 4 ml/min; stimulated CO 20 +/- 5 vs. 26 +/- 6 ml/min). Finally, using transfer function analysis, we found that, in resting conditions for both intact and MI mice, spontaneous variations in CO (> 0.1 Hz) were mainly due to those occurring in SV rather than in heart rate. These data indicate that CO can be measured chronically and reliably in conscious mice, also in conditions of heart failure, and that variations in preload are an important determinant of CO in this species. PMID:11832416

Janssen, B; Debets, J; Leenders, P; Smits, J

2002-03-01

27

Primary Extracorporeal Membrane Oxygenation Versus Primary Ventricular Assist Device Implantation in Low Cardiac Output Syndrome Following Cardiac Operation  

Microsoft Academic Search

Mechanical support is often the only therapeutic option in low cardiac output (LCO) following cardiac operation using extracorporeal circulation (ECC). However, the question whether primary ventricular assist device (VAD) or primary extracorporeal membrane oxy- genation (ECMO) followed by secondary VAD implanta- tion is superior remains unclear.We analyzed the outcome of 183 patients with LCO following ECC. Primary VAD implantation (VAD)

Stefan Klotz; Andreas Rukosujew; Henryk Welp; Christof Schmid; Tonny D. T. Tjan; Hans H. Scheld

2007-01-01

28

The cardiac output from blood pressure algorithms trial*  

PubMed Central

Objective The value of different algorithms that estimate cardiac output (CO) by analysis of a peripheral arterial blood pressure (ABP) waveform has not been definitively identified. In this investigation, we developed a testing data set containing a large number of radial ABP waveform segments and contemporaneous reference CO by thermodilution measurements, collected in an intensive care unit (ICU) patient population during routine clinical operations. We employed this data set to evaluate a set of investigational algorithms, and to establish a public resource for the meaningful comparison of alternative CO-from-ABP algorithms. Design A retrospective comparative analysis of eight investigational CO-from-ABP algorithms using the Multiparameter Intelligent Monitoring in Intensive Care II database. Setting Mixed medical/surgical ICU of a university hospital. Patients A total of 120 cases. Interventions None. Measurements CO estimated by eight investigational CO-from-ABP algorithms, and COTD as a reference. Main Results All investigational methods were significantly better than mean arterial pressure (MAP) at estimating direction changes in COTD. Only the formula proposed by Liljestrand and Zander in 1928 was a significantly better quantitative estimator of COTD compared with MAP (95% limits-of-agreement with COTD: –1.76/+1.41 L/min versus –2.20/+1.82 L/min, respectively; p < 0.001, per the Kolmogorov-Smirnov test). The Liljestrand method was even more accurate when applied to the cleanest ABP waveforms. Other investigational algorithms were not significantly superior to MAP as quantitative estimators of CO. Conclusions Based on ABP data recorded during routine intensive care unit (ICU) operations, the Liljestrand and Zander method is a better estimator of COTD than MAP alone. Our attempts to fully replicate commercially-available methods were unsuccessful, and these methods could not be evaluated. However, the data set is publicly and freely available, and developers and vendors of CO-from-ABP algorithms are invited to test their methods using these data. PMID:19112280

Sun, James X.; Reisner, Andrew T.; Saeed, Mohammed; Heldt, Thomas; Mark, Roger G.

2011-01-01

29

Measurement of cardiac output by use of noninvasively measured transient hemodilution curves with photoacoustic technology  

PubMed Central

We present the theoretical basis and experimental verification for cardiac output measurements using noninvasively measured hemodilution curves afforded with an indicator dilution technique and the emerging photoacoustic technology. A photoacoustic system noninvasively tracks a transient hemodilution effect induced by a bolus of isotonic saline as an indicator. As a result, a photoacoustic indicator dilution curve is obtained, which allows to estimate cardiac output from the developed algorithm. The experiments with a porcine blood circulatory phantom system demonstrated the feasibility of this technology towards the development of a noninvasive cardiac output measurement system for patient monitoring. PMID:24877007

Kang, Dongyel; Huang, Qiaojian; Li, Youzhi

2014-01-01

30

Measurement of cardiac output by use of noninvasively measured transient hemodilution curves with photoacoustic technology.  

PubMed

We present the theoretical basis and experimental verification for cardiac output measurements using noninvasively measured hemodilution curves afforded with an indicator dilution technique and the emerging photoacoustic technology. A photoacoustic system noninvasively tracks a transient hemodilution effect induced by a bolus of isotonic saline as an indicator. As a result, a photoacoustic indicator dilution curve is obtained, which allows to estimate cardiac output from the developed algorithm. The experiments with a porcine blood circulatory phantom system demonstrated the feasibility of this technology towards the development of a noninvasive cardiac output measurement system for patient monitoring. PMID:24877007

Kang, Dongyel; Huang, Qiaojian; Li, Youzhi

2014-05-01

31

Lithium Dilution Cardiac Output Measurements Using a Peripheral Injection Site: Comparison with Central Injection Technique and Thermodilution  

Microsoft Academic Search

Objective. The lithium dilution technique for the measurement of cardiac output by the central injection of lithium chloride was introduced by Linton et al. in 1993. In the present report, we compare lithium dilution cardiac output measurement (LD) by the peripheral injection of lithium chloride (pLD) and by central venous injection (cLD), cardiac output determined by electromagnetic flowmetry (EM), and

Tadayoshi Kurita; Koji Morita; Shigeru Kato; Hiroyuki Kawasaki; Mutsuhito Kikura; Tomiei Kazama; Kazuyuki Ikeda

1999-01-01

32

Echocardiographic assessment of cardiac disease  

NASA Technical Reports Server (NTRS)

The physical principles and current applications of echocardiography in assessment of heart diseases are reviewed. Technical considerations and unresolved points relative to the use of echocardiography in various disease states are stressed. The discussion covers normal mitral valve motion, mitral stenosis, aortic regurgitation, atrial masses, mitral valve prolapse, and idiopathic hypertrophic subaortic stenosis. Other topics concern tricuspic valve abnormalities, aortic valve disease, pulmonic valve, pericardial effusion, intraventricular septal motion, and left ventricular function. The application of echocardiography to congenital heart disease diagnosis is discussed along with promising ultrasonic imaging systems. The utility of echocardiography in quantitative evaluation of cardiac disease is demonstrated.

Popp, R. L.

1976-01-01

33

Comparison of bioimpedance versus thermodilution cardiac output during cardiac surgery: Evaluation of a second-generation bioimpedance device  

Microsoft Academic Search

Objective: To compare a second-generation thoracic electrical bioimpedance (TEB) hemodynamic monitoring system with the clinically used pulmonary artery catheter thermodilution (TD-PAC) system. Design: Blinded, simultaneous measurements at specified key time points during surgery. Setting: University teaching hospital cardiac surgical operating rooms. Participants: Forty-seven patients undergoing primary elective coronary artery bypass surgery. Interventions: Timed cardiac output measurements by thermodilution and continuous

Bruce D. Spiess; Muhammad A. Patel; Louise O. Soltow; Ian H. Wright

2001-01-01

34

Effects of aging on cardiac output, regional blood flow, and body composition in Fischer-344 rats.  

PubMed

The purpose of this study was to determine the effects of maturation and aging on cardiac output, the distribution of cardiac output, tissue blood flow (determined by using the radioactive-microsphere technique), and body composition in conscious juvenile (2-mo-old), adult (6-mo-old), and aged (24-mo-old) male Fischer-344 rats. Cardiac output was lower in juvenile rats (51 +/- 4 ml/min) than in adult (106 +/- 5 ml/min) or aged (119 +/- 10 ml/min) rats, but cardiac index was not different among groups. The proportion of cardiac output going to most tissues did not change with increasing age. However, the fraction of cardiac output to brain and spinal cord tissue and to skeletal muscle was greater in juvenile rats than that in the two adult groups. In addition, aged rats had a greater percent cardiac output to adipose tissue and a lower percent cardiac output to cutaneous and reproductive tissues than that in juvenile and adult rats. Differences in age also had little effect on mass-specific perfusion rates in most tissues. However, juvenile rats had lower flows to the pancreas, gastrointestinal tract, thyroid and parathyroid glands, and kidneys than did adult rats, and aged rats had lower flows to the white portion of rectus femoris muscle, spleen, thyroid and parathyroid glands, and prostate gland than did adult rats. Body mass of juvenile rats was composed of a lower percent adipose mass and a greater fraction of brain and spinal cord, heart, kidney, liver, and skeletal muscle than that of the adult and aged animals. Relative to the young adult rats, the body mass of aged animals had a greater percent adipose tissue mass and a lower percent skeletal muscle and skin mass. These data demonstrate that maturation and aging have a significant effect on the distribution of cardiac output but relatively little influence on mass-specific tissue perfusion rates in conscious rats. The old-age-related alterations in cardiac output distribution to adipose and cutaneous tissues appear to be associated with the increases in percent body fat and the decreases in the fraction of skin mass, respectively, whereas the decrease in the portion of cardiac output directed to reproductive tissue of aged rats appears to be related to a decrease in mass-specific blood flow to the prostate gland. PMID:9804586

Delp, M D; Evans, M V; Duan, C

1998-11-01

35

Cardiac risk assessment: decreasing postoperative complications.  

PubMed

Preoperative cardiac assessment helps identify patients undergoing noncardiac surgery who are at risk for significant postoperative cardiac complications and those who may benefit from additional preoperative evaluation and perioperative care. Advanced practice nurses can identify surgery- and patient-related risks by conducting a thorough health history and physical examination. Multiple risk indices and evidence-based guidelines are available to inform health care providers regarding patient evaluation and strategies to reduce postoperative cardiac risk. In general, preoperative tests are recommended only if the findings will influence medical therapy or perioperative monitoring or will require postponement of surgery until a cardiac condition can be corrected or stabilized. Medication management is a crucial component of the preoperative assessment; providers may need to initiate the use of beta-blockers and make decisions regarding continuing or withholding antiplatelet and anticoagulant therapy. Preoperative cardiac risk stratification, medication reconciliation, and device management are essential for providing safe care for patients. PMID:25645037

Thanavaro, Joanne L

2015-02-01

36

Continuous cardiac output measurement - Aspects of Doppler frequency analysis  

NASA Technical Reports Server (NTRS)

From the suprasternal notch blood flow velocity in the aorta can be measured non-invasively by a Doppler probe. Integration over systole after frequency analysis gives a measure of stroke volume if a separate diameter observation is incorporated. Frequency analysis by a zero crossing counter or by a set of parallel phaselock loops was less effective than a set of bandpass filters. Observations on dogs, baboons and humans before and after exercise or surgery suggest the indications to be useful. Application to judging heart failure by the effect of introducing a volume load is indicated. Changes in output also are measured in freely moving subjects.

Mackay, R. S.; Hechtman, H. B.

1975-01-01

37

Effect of Hemorrhage on Cardiac Output, PVP, Alodosterone and Diuresis during Immersion in Men  

NASA Technical Reports Server (NTRS)

The purpose of this study was to test the hypothesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q (sup dot) sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses.

Simanonok, K.; Greenleaf, John E.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

1990-01-01

38

Real-time cardiac output estimation of the circulatory system under left ventricular assistance  

Microsoft Academic Search

A method for indirect and real-time estimation of the cardiac output of the circulatory system supported by the left ventricular assist device (LVAD) is proposed. This method has low invasiveness and is useful for clinical applications of the LVAD since it needs only two measurements: the rate of blood outflow from the LVAD and the aortic pressure. The method is

Makoto Yoshizawa; Hiroshi Takeda; Makoto Miura; Tomoyuki Yambe; Yoshiaki Katahira; Shin-ichi Nitta

1993-01-01

39

Bioimpedance versus thermodilution cardiac output measurement: The bomed NCCOM3 after coronary bypass surgery  

Microsoft Academic Search

Values obtained for cardiac output (CO) were compared using thermodilution (TD) with those obtained using bioimpedance (Bi) as measured using the Bomed NCCOM3 (Revision 6) in 28 consecutive patients in the first 24h after coronary artery bypass surgery (CABS). In 46 paired measurements made in the first 12 h after CABS Bi values for CO were significantly lower than TD

A. N. Thomas; J. Ryan; B. R. H. Doran; B. J. Pollard

1991-01-01

40

Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon  

E-print Network

is that air-breathing in fishes evolved to allow survival in hypoxic water (Gunther, 1871; Barrell, 1916Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon T online 1 August 2007 Abstract Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air

Farrell, Anthony P.

41

Regulation of cardiac output and gut blood flow in the sea raven, Hemitripterus americanus  

Microsoft Academic Search

Coeliac artery blood flow (Fca) before and after feeding was recorded in the sea raven. To obtain basic information about the scope of cardiovascular adjustment in the sea raven, a separate series of experiments was performed, in which ventral (Pva), and dorsal (Pda) aortic blood pressure, heart rate (HR) and cardiac output (jaz) were monitored during rest and encouraged exercise.

Michael Axelsson; William R. Driedzic; Anthony P. Farrell; Stefan Nilsson

1989-01-01

42

Electrical velocimetry for measuring cardiac output in children with congenital heart disease  

Microsoft Academic Search

Background. The purpose of this study was to evaluate the agreement of cardiac output measurements obtained by electrical velocimetry (COEV) and those that derived from the direct Fick-oxygen principle (COF) in infants and children with congenital heart defects. Methods. Simultaneous measurements of COEV and COF were compared in 32 paediatric patients, aged 11 days to 17.8 yr, undergoing diagnostic right

K. Norozi; C. Beck; W. A. Osthaus; I. Wille; A. Wessel; H. Bertram

2008-01-01

43

THE EFFECT OF EXERCISE ON THE CARDIAC OUTPUT AND BLOOD FLOW DISTRIBUTION OF THE LARGESCALE SUCKER CATOSTOMUS MACROCHEILUS  

Microsoft Academic Search

Summary Cardiac output (Q. ) and blood flow distribution were measured in adult largescale suckers at rest and while swimming. Cardiac output was directly measured using an ultrasonic flowprobe in f ish during the summer (16?C), fall (10?C) and winter (5?C). Largescale suckers were adept at holding station against a current without swimming and, when engaged in this behavior, they

ALAN S. KOLOK; R. MICHAEL SPOONER; ANTHONY P. FARRELL

44

Peripartum cardiomyopathy: postpartum decompensation and use of non-invasive cardiac output monitoring.  

PubMed

The utility of a non-invasive cardiac output monitor (NICOM™) in guiding the peripartum management and identification of postpartum complications in a patient with severe peripartum cardiomyopathy is reported. A 31-year-old nulliparous woman at 35 weeks of gestation presented with a three-week history of worsening dyspnea and progressive functional deterioration. A transthoracic echocardiogram showed severe left ventricular systolic dysfunction with an ejection fraction <20%. Cardiac status was monitored using NICOM™ during labor and delivery. The baseline values were: cardiac output 5.3 L/min, total peripheral resistance 1549 dynes.sec/cm(5), stroke volume 42.1 mL and stroke volume variation 18%. She received early epidural analgesia during labor, titrated slowly with a loading dose of 0.0625% bupivacaine 10 mL and fentanyl 25 ?g, followed by patient-controlled epidural analgesia (0.0625% bupivacaine with fentanyl 2 ?g/mL, infusion at 10 mL/h, bolus dose 5 mL and lockout interval 10 min). After epidural drug administration, total peripheral resistance decreased, cardiac output increased, and satisfactory analgesia was obtained. She had an uneventful vaginal delivery with a forceps-assisted second stage after prophylactic administration of furosemide 20 mg. NICOM™ was discontinued after delivery. Fifteen hours post-delivery, the patient developed cardiogenic shock, which resolved after aggressive therapy with inotropes and furosemide. NICOM™ can be used to guide treatment during labor and delivery in patients with critical peripartum cardiomyopathy. We suggest that use of NICOM™ be extended into the postpartum period to detect signs of cardiac decompensation in such patients. PMID:24360329

Lorello, G; Cubillos, J; McDonald, M; Balki, M

2014-02-01

45

Continuous intraoperative noninvasive cardiac output monitoring using a new thoracic bioimpedance device  

Microsoft Academic Search

Objectives: To compare a new noninvasive bioimpedance device with the standard thermodilution method during the intraoperative period in high-risk patients undergoing oncological surgery.Design: Prospectively collected data with retrospective analysis.Setting: The study was undertaken at a university hospital, single institution.Participants: Twenty-three selected adults undergoing extensive, ablative oncological surgery.Interventions: Simultaneous measurements of cardiac output by a new bioimpedance method and the standard

Duraiyah Thangathurai; Christopher Charbonnet; Peter Roessler; Charles C. J. Wo; Maged Mikhail; Roland Yoshida; William C. Shoemaker

1997-01-01

46

Cardiac output measurement: Lack of agreement between thermodilution and thoracic electric bioimpedance in two clinical settings  

Microsoft Academic Search

Study objective: To determine the agreement between thermodilution (TD) and thoracic electric bioimpedance (TEB) techniques in cardiac output (CO) measurements in hyperdynamic kidney recipients and normodynamic patients subjected to radical cystectomy. The main objective was to determine the reliability of TEB in CO measurement.Design: Open two-group study.Setting: Unïversity hospital.Patients: 19 kidney recipients and 5 radical cystectomy patients.Interventions: Radial artery cannula

Mohamed M. Atallah; Atef D. Demain

1995-01-01

47

Pressure Pulse Contour-derived Stroke Volume and Cardiac Output in the Morbidly Obese Patient  

Microsoft Academic Search

Background  The pressure pulse contour method for measuring stroke volume (SV) and cardiac output (CO) has come of age. Various methods\\u000a have been proposed, but at this time no single technique has shown clear superiority over the others. This commentary and\\u000a review discusses the various methods, and particularly the pressure recording analytical method (PRAM). Dissection of the\\u000a method shows that vascular

Donald P. Bernstein

2008-01-01

48

Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon  

Microsoft Academic Search

Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air-breathing organ (ABO). We examined changes in cardiac output (V?b) associated with increases in air-breathing that accompany exercise and aquatic hypoxia. Juvenile (0.49 kg) and adult (1.21 kg) tarpon were allowed to recover in a swim flume at 27 °C after being instrumented with a Doppler flow probe around the ventral aorta

T. D. Clark; R. S. Seymour; K. Christian; R. M. G. Wells; J. Baldwin; A. P. Farrell

2007-01-01

49

Cardiac output distribution in miniature swine during locomotory exercise to VO\\/sub 3max  

Microsoft Academic Search

Distribution of cardiac output (CO) was studied in miniature swine (22 +\\/- 1 kg) during level treadmill exercise up to the speed (17.7 km\\/hr) that elicited maximal oxygen consumption (VO\\/sub 2max\\/) (60 +\\/- 4 m1\\/min\\/kg). COs and tissue blood flows (BFs) were measured with the radiolabelled microsphere technique. CO increased from a preexercise value of 2.1 +\\/- 0.5 1\\/min up

R. B. Armstrong; M. D. Delp; M. H. Laughlin

1986-01-01

50

Cardiac output variations in supine resting subjects during head-out cold water immersion  

NASA Astrophysics Data System (ADS)

Five men, aged 31.2 years (SD 2.3), under semi-nude conditions and resting in a dorsal reclining position, were exposed to thermoneutral air for 30 min, followed immediately by a cold water (15°C) immersion for 60 min. Cardiac output was measured using a dualbeam Doppler flow meter. During immersion in cold water, cardiac frequency ( f c) showed an initial bradycardia. The lowest values were reached at about 10 min after immersion, 58.3 (SD 2.5) to 48.3 (SD 7.8) beats min-1 ( P < 0.05). By the 20th min of exposure, f c had gradually risen to 70.0 beats min-1 (SD 6.6, P < 0.05). This change could be due to the inhibition of the initial vagal reflex by increased catecholamine concentration. Stroke volume ( V s) was significantly increased ( P < 0.05) during the whole cold immersion period. Cardiac output, increased from 3.57 (SD 0.50) to 6.26 (SD 1.33)1 min-1 ( P < 0.05) and its change with time was a function of both V s and f c. On the other hand, systolic flow acceleration was unchanged during the period of immersion. The changes in the respiratory variables (ventilation, oxygen uptake, carbon dioxide output and respiratory exchange ratio) during immersion showed an initial hyperventilation followed, as immersion proceeded, by a slower metabolic increase due to shivering.

Vogelaere, P.; Deklunder, G.; Lecroart, J.

1995-03-01

51

Comparison and reliability of two non-invasive acetylene uptake techniques for the measurement of cardiac output  

Microsoft Academic Search

Comparison and reliability of two non-invasive acetylene uptake techniques for the measurement of cardiac output. Thirteen trained male cyclists performed CO2 rebreathing (CO2RB) at intensities from rest to 200 W, and open-circuit acetylene uptake (OpCirc) and single-breath acetylene uptake (SB) at intensities from rest to 300 W, with all procedures using 50 W increments. Oxygen consumption \\u000a cardiac output \\u000a and heart rate (HR), were

D. W. Dibski; D. J. Smith; R. Jensen; S. R. Norris; G. T. Ford

2005-01-01

52

Automated non-invasive measurement of cardiac output: comparison of electrical bioimpedance and carbon dioxide rebreathing techniques  

Microsoft Academic Search

Two commercial automated, non-invasive systems for estimation of cardiac output were evaluated. Values of cardiac output obtained by electrical bioimpedance cardiography (BoMed NCCOM3 machine) were compared with values derived from an indirect Fick technique that uses carbon dioxide rebreathing (Gould 9000 IV system) during 103 simultaneous measurements made at rest in 19 randomly selected subjects and on exercise in 11

S A Smith; A E Russell; M J West; J Chalmers

1988-01-01

53

99mTc-Labelled serum albumin in cardiac output and blood volume studies  

PubMed Central

The use of human serum albumin labelled with iodine-131 (RIHSA) as the radioactive indicator in the measurement of cardiac output by the external counting technique is not ideal since the emission characteristics, physical half-life, and physiological fate restrict the amount that can be administered. A more suitable material, especially because of the short physical half-life of the isotope involved, is albumin labelled with technetium-99m. This communication describes a simple three-stage process for the preparation of such a complex which was then tested in subjects with no impairment of cardiac performance for its suitability in assays of cardiac output by the external counting method. Values were within the same range as those obtained with RIHSA in comparable subjects. Blood volumes estimated with 99mTc-albumin were within the limits of physiological variation of values derived with RIHSA in the same subjects. Serial blood samplings and urine collection during a period of 24 hours after administration showed that the preparation was lost continuously from the circulation at a more rapid rate than RIHSA. The greatest loss was in the first few hours when most of the urinary excretion of the isotope occurred. Comparison of the present data with published results using an alternative preparation suggests that our product may be more stable. PMID:4935673

Williams, M. Jean; Deegan, T.

1971-01-01

54

High flow variant postural orthostatic tachycardia syndrome amplifies the cardiac output response to exercise in adolescents  

PubMed Central

Abstract Postural orthostatic tachycardia syndrome (POTS) is characterized by chronic fatigue and dizziness and affected individuals by definition have orthostatic intolerance and tachycardia. There is considerable overlap of symptoms in patients with POTS and chronic fatigue syndrome (CFS), prompting speculation that POTS is akin to a deconditioned state. We previously showed that adolescents with postural orthostatic tachycardia syndrome (POTS) have excessive heart rate (HR) during, and slower HR recovery after, exercise – hallmarks of deconditioning. We also noted exaggerated cardiac output during exercise which led us to hypothesize that tachycardia could be a manifestation of a high output state rather than a consequence of deconditioning. We audited records of adolescents presenting with long?standing history of any mix of fatigue, dizziness, nausea, who underwent both head?up tilt table test and maximal exercise testing with measurement of cardiac output at rest plus 2–3 levels of exercise, and determined the cardiac output () versus oxygen uptake () relationship. Subjects with chronic fatigue were diagnosed with POTS if their HR rose ?40 beat·min?1 with head?up tilt. Among 107 POTS patients the distribution of slopes for the , relationship was skewed toward higher slopes but showed two peaks with a split at ~7.0 L·min?1 per L·min?1, designated as normal (5.08 ± 1.17, N = 66) and hyperkinetic (8.99 ± 1.31, N = 41) subgroups. In contrast, cardiac output rose appropriately with in 141 patients with chronic fatigue but without POTS, exhibiting a normal distribution and an average slope of 6.10 ± 2.09 L·min?1 per L·min?1. Mean arterial blood pressure and pulse pressure from rest to exercise rose similarly in both groups. We conclude that 40% of POTS adolescents demonstrate a hyperkinetic circulation during exercise. We attribute this to failure of normal regional vasoconstriction during exercise, such that patients must increase flow through an inappropriately vasodilated systemic circulation to maintain perfusion pressure. PMID:25168872

Pianosi, Paolo T.; Goodloe, Adele H.; Soma, David; Parker, Ken O.; Brands, Chad K.; Fischer, Philip R.

2014-01-01

55

Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT  

NASA Astrophysics Data System (ADS)

Contrast enhancement on cardiac CT provides valuable information about myocardial perfusion and methods have been proposed to assess perfusion with static and dynamic acquisitions. There is a lack of knowledge and consensus on the appropriate approach to ensure 1) sufficient diagnostic accuracy for clinical decisions and 2) low radiation doses for patient safety. This work developed a thorough dynamic CT simulation and several accepted blood flow estimation techniques to evaluate the performance of perfusion assessment across a range of acquisition and estimation scenarios. Cardiac CT acquisitions were simulated for a range of flow states (Flow = 0.5, 1, 2, 3 ml/g/min, cardiac output = 3,5,8 L/min). CT acquisitions were simulated with a validated CT simulator incorporating polyenergetic data acquisition and realistic x-ray flux levels for dynamic acquisitions with a range of scenarios including 1, 2, 3 sec sampling for 30 sec with 25, 70, 140 mAs. Images were generated using conventional image reconstruction with additional image-based beam hardening correction to account for iodine content. Time attenuation curves were extracted for multiple regions around the myocardium and used to estimate flow. In total, 2,700 independent realizations of dynamic sequences were generated and multiple MBF estimation methods were applied to each of these. Evaluation of quantitative kinetic modeling yielded blood flow estimates with an root mean square error (RMSE) of ~0.6 ml/g/min averaged across multiple scenarios. Semi-quantitative modeling and qualitative static imaging resulted in significantly more error (RMSE = ~1.2 and ~1.2 ml/min/g respectively). For quantitative methods, dose reduction through reduced temporal sampling or reduced tube current had comparable impact on the MBF estimate fidelity. On average, half dose acquisitions increased the RMSE of estimates by only 18% suggesting that substantial dose reductions can be employed in the context of quantitative myocardial blood flow estimation. In conclusion, quantitative model-based dynamic cardiac CT perfusion assessment is capable of accurately estimating MBF across a range of cardiac outputs and tissue perfusion states, outperforms comparable static perfusion estimates, and is relatively robust to noise and temporal subsampling.

Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

2014-03-01

56

Quantification of Cardiac Sac Network Effects on a Movement-Related Parameter of Pyloric Network Output in the Lobster  

E-print Network

Output in the Lobster JEFF B. THUMA AND SCOTT L. HOOPER Neuroscience Program, Department of Biological on a movement-related parameter of pyloric network output in the lobster. J Neurophysiol 89: 745­753, 2003; 10 of cardiac sac activity on the OSF of all pyloric neurons in the lobster, Panulirus interruptus

Hooper, Scott

57

Negative pressure breathing increases cardiac output and nitrogen elimination in seated subjects.  

PubMed

During denitrogenation for rescue, crew members of an internally pressurized disabled submarine (DISSUB) must sit upright, which may hamper venous return, cardiac output and peripheral circulation. Since negative pressure breathing (NPB) might counteract this problem, denitrogenation was measured in sitting subjects performing NPB. Seven male subjects completed 125-minute nitrogen (N2) washouts breathing either 100% oxygen (O2) or a normoxic gas (21% O2 in argon) in control conditions and intermittent (I: inspirations only) or continuous (C) NPB at -10 or -15 cmH2O. N2 elimination was measured using a closed rebreathing system. INPB (intermittent) (-15cmH2O) and CNPB (continous breathing) (-10 and -15cmH2O) increased cardiac output (CO) 9% during both O2 and normoxic breathing. Systolic and diastolic blood pressures were unaffected by the CO increase, suggesting a peripheral vasodilatation and enhanced tissue perfusion leading to increased N2 elimination. With the CO boost, N2 washout increased 6% breathing O2 at -15 cmH2O CNPB and INPB, while during normoxic breathing there were 6% and 12% increases due to CNBP, -10 and -15 respectively and 6% with -15cmH2O INPB; breathing 100% O2 yielding 5% to 15% less N2 washout than normoxic breathing. Negative pressure breathing during denitrogenation may facilitate decompression in divers and in crew members being rescued from a DISSUB. PMID:24224284

Lundgren, Claes E G; Eckhardt, Lukas G; Senf, Curtis J; Bowdwin, Melina R; Pendergast, David R

2013-01-01

58

The neuromuscular transform of the lobster cardiac system explains the opposing effects of a neuromodulator on muscle output.  

PubMed

Motor neuron activity is transformed into muscle movement through a cascade of complex molecular and biomechanical events. This nonlinear mapping of neural inputs to motor behaviors is called the neuromuscular transform (NMT). We examined the NMT in the cardiac system of the lobster Homarus americanus by stimulating a cardiac motor nerve with rhythmic bursts of action potentials and measuring muscle movements in response to different stimulation patterns. The NMT was similar across preparations, which suggested that it could be used to predict muscle movement from spontaneous neural activity in the intact heart. We assessed this possibility across semi-intact heart preparations in two separate analyses. First, we performed a linear regression analysis across 122 preparations in physiological saline to predict muscle movements from neural activity. Under these conditions, the NMT was predictive of contraction duty cycle but was unable to predict contraction amplitude, likely as a result of uncontrolled interanimal variability. Second, we assessed the ability of the NMT to predict changes in motor output induced by the neuropeptide C-type allatostatin. Wiwatpanit et al. (2012) showed that bath application of C-type allatostatin produced either increases or decreases in the amplitude of the lobster heart contractions. We show that an important component of these preparation-dependent effects can arise from quantifiable differences in the basal state of each preparation and the nonlinear form of the NMT. These results illustrate how properly characterizing the relationships between neural activity and measurable physiological outputs can provide insight into seemingly idiosyncratic effects of neuromodulators across individuals. PMID:24133260

Williams, Alex H; Calkins, Andrew; O'Leary, Timothy; Symonds, Renee; Marder, Eve; Dickinson, Patsy S

2013-10-16

59

The Neuromuscular Transform of the Lobster Cardiac System Explains the Opposing Effects of a Neuromodulator on Muscle Output  

PubMed Central

Motor neuron activity is transformed into muscle movement through a cascade of complex molecular and biomechanical events. This nonlinear mapping of neural inputs to motor behaviors is called the neuromuscular transform (NMT). We examined the NMT in the cardiac system of the lobster Homarus americanus by stimulating a cardiac motor nerve with rhythmic bursts of action potentials and measuring muscle movements in response to different stimulation patterns. The NMT was similar across preparations, which suggested that it could be used to predict muscle movement from spontaneous neural activity in the intact heart. We assessed this possibility across semi-intact heart preparations in two separate analyses. First, we performed a linear regression analysis across 122 preparations in physiological saline to predict muscle movements from neural activity. Under these conditions, the NMT was predictive of contraction duty cycle but was unable to predict contraction amplitude, likely as a result of uncontrolled interanimal variability. Second, we assessed the ability of the NMT to predict changes in motor output induced by the neuropeptide C-type allatostatin. Wiwatpanit et al. (2012) showed that bath application of C-type allatostatin produced either increases or decreases in the amplitude of the lobster heart contractions. We show that an important component of these preparation-dependent effects can arise from quantifiable differences in the basal state of each preparation and the nonlinear form of the NMT. These results illustrate how properly characterizing the relationships between neural activity and measurable physiological outputs can provide insight into seemingly idiosyncratic effects of neuromodulators across individuals. PMID:24133260

Williams, Alex H.; Calkins, Andrew; O'Leary, Timothy; Symonds, Renee; Marder, Eve

2013-01-01

60

Assessment of Diastolic Function by Cardiac MRI  

Microsoft Academic Search

Cardiac magnetic resonance imaging (MRI) techniques continue to change rapidly, and cardiac MRI is developing as an alternative\\u000a noninvasive technique having the unique potential of three-dimensional function analysis with great accuracy and reproducibility.\\u000a Advances in rapid cardiac MRI technology are making real-time imaging possible at approaching echocardiographic frame rates.\\u000a Together with the increasing availability of cardiac MRI machines, cardiac MRI

Bernard P. Paelinck; Hildo J. Lamb

61

The use of electrical cardiometry for continuous cardiac output monitoring in preterm neonates: a validation study.  

PubMed

Background?Electrical cardiometry (EC) is a continuous noninvasive method for measuring cardiac output (CO), but there are limited data on premature infants. We evaluated the utility of EC monitoring by comparing the results obtained using EC to measurements of CO and systemic blood flow using echocardiography (ECHO). Methods?In this prospective observational study, 40 preterm neonates underwent 108-paired EC and ECHO measurements. Results?There were correlations between EC-CO and left ventricular output (LVO, p?output (RVO, p?

Song, R; Rich, W; Kim, J H; Finer, N N; Katheria, A C

2014-12-01

62

Noninvasive aortic bloodflow by Pulsed Doppler Echocardiography (PDE) compared to cardiac output by the direct Fick procedure  

NASA Technical Reports Server (NTRS)

Left ventricular stroke volume was estimated from the systolic velocity integral in the ascending aorta by pulsed Doppler Echocardiography (PDE) and the cross sectional area of the aorta estimated by M mode echocardiography on 15 patients with coronary disease undergoing right catheterization for diagnostic purposes. Cardiac output was calculated from stroke volume and heart volume using the PDE method as well as the Fick procedure for comparison. The mean value for the cardiac output via the PDE method (4.42 L/min) was only 6% lower than for the cardiac output obtained from the Fick procedure (4.69 L/min) and the correlation between the two methods was excellent (r=0.967, p less than .01). The good agreement between the two methods demonstrates that the PDE technique offers a reliable noninvasive alternative for estimating cardiac output, requiring no active cooperation by the subject. It was concluded that the Doppler method is superior to the Fick method in that it provides beat by beat information on cardiac performance.

1980-01-01

63

Cardiac cell proliferation assessed by EdU, a novel analysis of cardiac regeneration.  

PubMed

Emerging evidence suggests that mammalian hearts maintain the capacity for cardiac regeneration. Rapid and sensitive identification of cardiac cellular proliferation is prerequisite for understanding the underlying mechanisms and strategies of cardiac regeneration. The following immunologically related markers of cardiac cells were analyzed: cardiac transcription factors Nkx2.5 and Gata 4; specific marker of cardiomyocytes TnT; endothelial cell marker CD31; vascular smooth muscle marker smooth muscle myosin IgG; cardiac resident stem cells markers IsL1, Tbx18, and Wt1. Markers were co-localized in cardiac tissues of embryonic, neonatal, adult, and pathological samples by 5-ethynyl-2'-deoxyuridine (EdU) staining. EdU was also used to label isolated neonatal cardiomyocytes in vitro. EdU robustly labeled proliferating cells in vitro and in vivo, co-immunostaining with different cardiac cells markers. EdU can rapidly and sensitively label proliferating cardiac cells in developmental and pathological states. Cardiac cell proliferation assessed by EdU is a novel analytical tool for investigating the mechanism and strategies of cardiac regeneration in response to injury. PMID:25480318

Zeng, Bin; Tong, Suiyang; Ren, Xiaofeng; Xia, Hao

2014-12-01

64

Reference values for total blood volume and cardiac output in humans  

SciTech Connect

Much research has been devoted to measurement of total blood volume (TBV) and cardiac output (CO) in humans but not enough effort has been devoted to collection and reduction of results for the purpose of deriving typical or {open_quotes}reference{close_quotes} values. Identification of normal values for TBV and CO is needed not only for clinical evaluations but also for the development of biokinetic models for ultra-short-lived radionuclides used in nuclear medicine (Leggett and Williams 1989). The purpose of this report is to offer reference values for TBV and CO, along with estimates of the associated uncertainties that arise from intra- and inter-subject variation, errors in measurement techniques, and other sources. Reference values are derived for basal supine CO and TBV in reference adult humans, and differences associated with age, sex, body size, body position, exercise, and other circumstances are discussed.

Williams, L.R. [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences] [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences

1994-09-01

65

A case series of real-time hemodynamic assessment of high output heart failure as a complication of arteriovenous access in dialysis patients.  

PubMed

Congestive heart failure (CHF) is an important source of morbidity and mortality in end-stage renal disease patients. Although CHF is commonly associated with low cardiac output (CO), it may also occur in high CO states. Multiple conditions are associated with increased CO including congenital or acquired arteriovenous fistulae or arteriovenous grafts. Increased CO resulting from permanent AV access in dialysis patients has been shown to induce structural and functional cardiac changes, including the development of eccentric left ventricle hypertrophy. Often, the diagnosis of high output heart failure requires invasive right heart monitoring in the acute care setting such as a medical or cardiac intensive care unit. The diagnosis of an arteriovenous access causing high output heart failure is usually confirmed after the access is ligated surgically. We present for the first time, a case for real-time hemodynamic assessment of high output heart failure due to AV access by interventional nephrology in the cardiac catheterization suite. PMID:24673654

Singh, Sarguni; Elramah, Mohsen; Allana, Salman S; Babcock, Michael; Keevil, Jon G; Johnson, Maryl R; Yevzlin, Alexander S; Chan, Micah R

2014-11-01

66

Rowing increases stroke volume and cardiac output to a greater extent than cycling.  

PubMed

Exercise stimulates increases in heart rate (HR), stroke volume (SV) and cardiac output (CO). These adaptive mechanisms are strongly dependent on the type of exercise. Both rowing and cycling are widely used for physical training worldwide; however, evidence regarding the differences in major hemodynamic parameters during rowing and cycling remains insufficient. Ten healthy male volunteers were randomly assigned to perform either a rowing or cycling exercise. After 20 min rest, the group who had rowed first performed the cycling exercise and vice versa. Exercise was performed at a power-to-weight ratio of 2 W/kg for 2 min. HR, SV, CO and blood pressure (BP) were measured noninvasively using pulse-wave analysis at baseline and immediately after each exercise. HR, SV and CO were significantly higher after exercise than at rest. Whereas HR was comparable between rowing and cycling, SV and CO were significantly higher after rowing than after cycling. BP was comparable among all three measurements. Rowing increased SV and CO to a greater extent than cycling, whereas HR and BP were not influenced by the type of exercise. Our data suggest that rowing leads to more extensive stimulation of cardiac contractility and/or decreases in peripheral vascular resistance compared with cycling. PMID:25317691

Horn, P; Ostadal, P; Ostadal, B

2014-10-15

67

Increased systemic cardiac output improves arterial oxygen saturation in bidirectional cavopulmonary shunt.  

PubMed

The low arterial oxygen saturation (SaO2) after bidirectional cavopulmonary shunt (BCPS) predicts poor prognosis. The venous oxygen saturation of inferior vena cava (SivcO2), as well as the pulmonary blood flow/systemic blood flow ratio (Q p/Q s) affects the SaO2. The purpose of this study is to determine whether SivcO2 or Q p/Q s should be increased to achieve better outcomes after BCPS. Forty-eight patients undergoing BCPS were included. Data of patients' age and body weight, SivcO2, Q p/Q s, pulmonary artery (PA) pressure and resistance, PA area index, morphology of ventricle, atrioventricular valve regurgitation, and history of PA plasty were collected. Stepwise multiple logistic regression analyses were used to investigate which of the factors most affected the SaO2 after BCPS. There was a significant correlation between SivcO2 and SaO2 (r = 0.771, P < 0.00001). There was no strong correlation between Q p/Q s and SaO2 (r = 0.358, P < 0.05). Stepwise multiple logistic regression analyses revealed that both SivcO2 (r = 0.49, 95 % confidence interval (CI) 0.37-0.62, P < 0.0001) and Q p/Q s (r = 11.1, 95 % CI 3.3-18.9, P = 0.007) most affected SaO2 after BCPS. Since the SivcO2 has a stronger correlation than Q p/Q s with SaO2, despite the fact that both raising Q p/Q s and raising cardiac output can increase SaO2, raising cardiac output should be considered prior to Q p/Q s to raise the SaO2 after BCPS. PMID:24213974

Oka, Norihiko; Miyaji, Kagami; Kitamura, Tadashi; Itatani, Keiichi; Yoshii, Takeshi; Inoue, Nobuyuki; Fukunishi, Takuma; Shibata, Ko; Torii, Shinzo

2015-01-01

68

Noninvasive cardiac output measurement by inert gas rebreathing in suspected pulmonary hypertension.  

PubMed

The objective of this study was to evaluate inert gas rebreathing (IGR) reliability in cardiac output (CO) measurement compared with Fick method and thermodilution. IGR is a noninvasive method for CO measurement; CO by IGR is calculated as pulmonary blood flow plus intrapulmonary shunt. IGR may be ideal for follow-up of patients with pulmonary hypertension (PH), sparing the need of repeated invasive right-sided cardiac catheterization. Right-sided cardiac catheterization with CO measurement by thermodilution, Fick method, and IGR was performed in 125 patients with possible PH by echocardiography. Patients were grouped according to right-sided cardiac catheterization-measured mean pulmonary and wedge pressures: normal pulmonary arterial pressure (n = 20, mean pulmonary arterial pressure = 18 ± 3 mm Hg, pulmonary capillary wedge pressure = 11 ± 5 mm Hg), PH and normal pulmonary capillary wedge pressure (PH-NW, n = 37 mean pulmonary arterial pressure = 42 ± 13 mm Hg, pulmonary capillary wedge pressure = 11 ± 6 mm Hg), and PH and high pulmonary capillary wedge pressure (PH-HW, n = 68, mean pulmonary arterial pressure = 37 ± 9 mm Hg, pulmonary capillary wedge pressure = 24 ± 6 mm Hg). Thermodilution and Fick measurements were comparable. Fick and IGR agreement was observed in normal pulmonary arterial pressure (CO = 4.10 ± 1.14 and 4.08 ± 0.97 L/min, respectively), whereas IGR overestimated Fick in patients with PH-NW and those with PH-HW because of intrapulmonary shunting overestimation in hypoxemic patients. When patients with arterial oxygen saturation (SO2) ?90% were excluded, IGR and Fick agreement improved in PH-NW (CO = 4.90 ± 1.70 and 4.76 ± 1.35 L/min, respectively) and PH-HW (CO = 4.05 ± 1.04 and 4.10 ± 1.17 L/min, respectively). In hypoxemic patients, we estimated pulmonary shunt as Fick - pulmonary blood flow and calculated shunt as: -0.2423 × arterial SO2 + 21.373 L/min. In conclusion, IGR is reliable for CO measurement in patients with PH with arterial SO2 >90%. For patients with arterial SO2 ?90%, a new formula for shunt calculation is proposed. PMID:24315114

Farina, Stefania; Teruzzi, Giovanni; Cattadori, Gaia; Ferrari, Cristina; De Martini, Stefano; Bussotti, Maurizio; Calligaris, Giuseppe; Bartorelli, Antonio; Agostoni, Piergiuseppe

2014-02-01

69

Non-invasive beat-to-beat cardiac output monitoring by an improved method of transthoracic bioimpedance measurement  

Microsoft Academic Search

The report describes a method of impedance cardiography using an improved estimate of thoracic volume. The formulas and their implementation in hardware and software are explained and new shortband electrodes are described which generate a good homogeneous thoracic field. Examples of stroke volume and cardiac output curves underline the capabilities of the monitoring system “Task Force® Monitor”. In several experiments,

J. Fortin; W. Habenbacher; A. Heller; A. Hacker; R. Grüllenbergera; J. Innerhofer; H. Passath; Ch. Wagner; G. Haitchi; D. Flotzinger; R. Pacher; P. Wach

2006-01-01

70

Effect of heat stress on cardiac output and systemic vascular conductance during simulated hemorrhage to presyncope in young men  

PubMed Central

During moderate actual or simulated hemorrhage, as cardiac output decreases, reductions in systemic vascular conductance (SVC) maintain mean arterial pressure (MAP). Heat stress, however, compromises the control of MAP during simulated hemorrhage, and it remains unknown whether this response is due to a persistently high SVC and/or a low cardiac output. This study tested the hypothesis that an inadequate decrease in SVC is the primary contributing mechanism by which heat stress compromises blood pressure control during simulated hemorrhage. Simulated hemorrhage was imposed via lower body negative pressure (LBNP) to presyncope in 11 passively heat-stressed subjects (increase core temperature: 1.2 ± 0.2°C; means ± SD). Cardiac output was measured via thermodilution, and SVC was calculated while subjects were normothermic, heat stressed, and throughout subsequent LBNP. MAP was not changed by heat stress but was reduced to 45 ± 12 mmHg at the termination of LBNP. Heat stress increased cardiac output from 7.1 ± 1.1 to 11.7 ± 2.2 l/min (P < 0.001) and increased SVC from 0.094 ± 0.018 to 0.163 ± 0.032 l·min?1·mmHg?1 (P < 0.001). Although cardiac output at the onset of syncopal symptoms was 37 ± 16% lower relative to pre-LBNP, presyncope cardiac output (7.3 ± 2.0 l/min) was not different than normothermic values (P = 0.46). SVC did not change throughout LBNP (P > 0.05) and at presyncope was 0.168 ± 0.044 l·min?1·mmHg?1. These data indicate that in humans a cardiac output adequate to maintain MAP while normothermic is no longer adequate during a heat-stressed-simulated hemorrhage. The absence of a decrease in SVC at a time of profound reductions in MAP suggests that inadequate control of vascular conductance is a primary mechanism compromising blood pressure control during these conditions. PMID:22367508

Ganio, Matthew S.; Overgaard, Morten; Seifert, Thomas; Secher, Niels H.; Johansson, Pär I.; Meyer, Martin A. S.

2012-01-01

71

A comparison of dobutamine and levosimendan on hepatic blood flow in patients with a low cardiac output state after cardiac surgery: a randomised controlled study.  

PubMed

Liver dysfunction due to a low cardiac output state after cardiac surgery is associated with a poor prognosis, but whether one inotrope is superior to another in improving hepatic perfusion remains uncertain. This study compared the systemic and hepatic haemodynamic effects of levosimendan to dobutamine in patients with a low cardiac output state (cardiac index < 2.2 l/min/m2) after on-pump cardiac surgery. A total of 25 patients were randomised to receive either an intravenous bolus of levosimendan (12 µg/kg) over 15 minutes, followed by an infusion of 0.2 µg/kg/min for 24 hours, or an infusion of dobutamine 7.5 µg/kg/min for 24 hours and completed the study. The systemic and hepatic haemodynamics at 24 and 48 hours were all better after levosimendan than dobutamine (dobutamine group: cardiac index (l/min/m2)=2.51 [standard deviation ±0.29], 2.40±0.23; portal vein flow (ml/min): 614.0±124.7, 585.9±144.8; pulsatility index: 2.02±0,28, 2.98±0.27 versus the levosimendan group: cardiac index: 3.02± 0.27, 2.98± 0.30; portal vein flow: 723.0± 143.5, 702.9±117.8; pulsatility index: 1.71±0.26, 1.73±0.27). The improvement in portal vein blood flow at 48 hours was significantly better after levosimendan than dobutamine (41% vs. 11% increment from baseline, P<0.05). In addition, there was a significant reduction in hepatic artery resistance after levosimendan but not dobutamine (resistance index reduction 6.5% vs. 0%, P<0.05). In summary, levosimendan can be considered as a selective liver vasodilator and can improve hepatic blood flow through both the hepatic artery and portal venous system, whereas dobutamine can only improve the portal venous blood flow without vasodilating the hepatic artery. PMID:24180712

Alvarez, J; Baluja, A; Selas, S; Otero, P; Rial, M; Veiras, S; Caruezo, V; Taboada, M; Rodriguez, I; Castroagudin, J; Tome, S; Rodriguez, A; Rodriguez, J

2013-11-01

72

Pulmonary diffusing capacity, capillary blood volume, and cardiac output during sustained microgravity  

NASA Technical Reports Server (NTRS)

We measured pulmonary diffusing capacity (DL), diffusing capacity per unit lung volume, pulmonary capillary blood volume (Vc), membrane diffusing capacity (Dm), pulmonary capillary blood flow or cardiac output (Qc), and cardiac stroke volume (SV) in four subjects exposed to nine days of microgravity. DL in microgravity was elevated compared with preflight standing values and was higher than preflight supine because of the elevation of both Vc and Dm. The elevation in Vc was comparable to that measured supine in 1 G, but the increase in Dm was in sharp contrast to the supine value. We postulate that, in 0 G, pulmonary capillary blood is evenly distributed throughout the lung, providing for uniform capillary filling, leading to an increase in the surface area available for diffusion. By contrast, in the supine 1-G state, the capillaries are less evenly filled, and although a similar increase in blood volume is observed, the corresponding increase in surface area does not occur. DL and its subdivisions showed no adaptive changes from the first measurement 24 h after the start of 0 G to eight days later. Similarly, there were no trends in the postflight data, suggesting that the principal mechanism of these changes was gravitational. The increase in Dm suggests that subclinical pulmonary edema did not result from exposure to 0 G. Qc was modestly increased inflight and decreased postflight compared with preflight standing. Compared with preflight standing, SV was increased 46 percent inflight and decreased 14 percent in the 1st week postflight. There were temporal changes in Qc and SV during 0 G, with the highest values recorded at the first measurement, 24 h into the flight. The lowest values of Qc and SV occurred on the day of return.

Prisk, G. K.; Guy, Harold J. B.; Elliott, Ann R.; Deutschman, Robert A., III; West, John B.

1993-01-01

73

Combined first pass and gated blood pool radionuclide studies in the hemodynamic-cardiac evaluation of patients with low cardiac output  

SciTech Connect

Cardiac output (CO) is frequently used in the evaluation of cardiac function but low CO does not necessarily reflect heart failure. Similarly, low ejection fraction (EF) can be present in compensated heart diseases. In order to evaluate cardiac performance in relation to systematic hemodynamics, the authors used a multifactorial approach for the determination of CO, EF, pulmonary mean transit time (MTT), ratio of cardiopulmonary volume over total blood volume (CPV/TBV as an index of venous tone) all obtained from a single injection of 99m Tc-HSA. Four different conditions associated with low CO (less than or equal to 2.1 L/min/m/sup 2/) were evaluated. The combined use of CO, EF, MTT and CPV/TBV allowed a better understanding of the myocardial and peripheral circulatory factors associated with low CO states. This is helpful in the selection and follow-up of appropriate therapeutic intervention.

Abi-Mansour, P.; Fouad, F.M.; Sheeler, L.R.; Bravo, E.L.; MacIntyre, W.J.; Tarazi, R.C.

1984-01-01

74

Cardiac Output is Not a Significant Source of Low Frequency Mean Arterial Pressure Variability  

PubMed Central

Spontaneous mean arterial pressure (MAP) variability may be mainly due to fluctuations in cardiac output (CO) and total peripheral resistance (TPR). While high frequency (HF ~ 0.25 Hz) oscillations in MAP are ultimately driven by respiration, the source of low frequency (LF ~ 0.1 Hz) fluctuations has not been fully elucidated. It is known that CO buffers these oscillations, but there is no evidence on its potential role in also generating them. The main goal was to determine whether CO is a source of LF variability in MAP. Six dogs were chronically instrumented to obtain beat-to-beat measurements of CO and MAP while the dogs were fully awake and at rest. A causal dynamic model was identified to relate the fluctuations in CO to MAP. The model was then used to predict the MAP fluctuations from the CO fluctuations. The CO fluctuations were able to predict about 70% of the MAP oscillations in the HF band but showed no predictive value in the LF band. Hence, respiration induces CO fluctuations in the HF band that, in turn, cause MAP oscillations, while TPR fluctuations appear to be the dominant mediator of LF fluctuations of MAP. CO is not a significant source of these oscillations, and it may only be responsible for dampening them, likely through the baroreflex. PMID:23969898

Aletti, F; Hammond, RL; Sala-Mercado, JA; Chen, X; O’Leary, DS; Baselli, G; Mukkamala, R

2013-01-01

75

Continuous, non-invasive techniques to determine cardiac output in children after cardiac surgery: evaluation of transesophageal Doppler and electric velocimetry  

Microsoft Academic Search

Background. Continuous and non-invasive measurement of cardiac output (CO) may contribute helpful information to the care and treatment\\u000a of the critically ill pediatric patient. Different methods are available but their clinical verification is still a major\\u000a problem. Aim. Comparison of reliability and safety of two continuous non-invasive methods with transthoracic echocardiography (TTE) for\\u000a CO measurement: electric velocimetry technique (EV, Aesculon™)

Stephan Schubert; Thomas Schmitz; Markus Weiss; Nicole Nagdyman; Michael Huebler; Vladimir Alexi-Meskishvili; Felix Berger; Brigitte Stiller

2008-01-01

76

Assessing Depression in Cardiac Patients: What Measures Should Be Considered?  

PubMed Central

It is highly recommended to promptly assess depression in heart disease patients as it represents a crucial risk factor which may result in premature deaths following acute cardiac events and a more severe psychopathology, even in cases of subsequent nonfatal cardiac events. Patients and professionals often underestimate or misjudge depressive symptomatology as cardiac symptoms; hence, quick, reliable, and early mood changes assessments are warranted. Failing to detect depressive signals may have detrimental effects on these patients' wellbeing and full recovery. Choosing gold-standard depression investigations in cardiac patients that fit a hospitalised cardiac setting well is fundamental. This paper will examine eight well established tools following Italian and international guidelines on mood disorders diagnosis in cardiac patients: the Hospital Anxiety and Depression Scale (HADS), the Cognitive Behavioural Assessment Hospital Form (CBA-H), the Beck Depression Inventory (BDI), the two and nine-item Patient Health Questionnaire (PHQ-2, PHQ-9), the Depression Interview and Structured Hamilton (DISH), the Hamilton Rating Scale for Depression (HAM-D/HRSD), and the Composite International Diagnostic Interview (CIDI). Though their strengths and weaknesses may appear to be homogeneous, the BDI-II and the PHQ are more efficient towards an early depression assessment within cardiac hospitalised patients. PMID:24649359

Ceccarini, M.; Manzoni, G. M.; Castelnuovo, G.

2014-01-01

77

First in vivo application and evaluation of a novel method for non-invasive estimation of cardiac output.  

PubMed

Surgical or critically ill patients often require continuous assessment of cardiac output (CO) for diagnostic purposes or for guiding therapeutic interventions. A new method of non-invasive CO estimation has been recently developed, which is based on pressure wave analysis. However, its validity has been examined only in silico. Aim of this study was to evaluate in vivo the reproducibility and accuracy of the "systolic volume balance" method (SVB). Twenty two subjects underwent 2-D transthoracic echocardiography for CO measurement (reference value of CO). The application of SVB method required aortic pressure wave analysis and estimation of total arterial compliance. Aortic pulses were derived by mathematical transformation of radial pressure waves recorded by applanation tonometry. Total compliance was estimated by the "pulse pressure" method. The agreement, association, variability, bias and precision between Doppler and SVB measures of CO were evaluated by intraclass correlation coefficient (ICC), mean difference, SD of differences, percentage error (PR) and Bland-Altman analysis. SVB yielded very reproducible CO estimates (ICC=0.84, mean difference 0.27 ± 0.73 L/min, PR = 16.7%). SVB-derived CO was comparable with Doppler measurements, indicating a good agreement and accuracy (ICC = 0.74, mean difference = -0.22 ± 0.364 L/min, PR ? 15). The basic mathematical and physical principles of the SVB method provide highly reproducible and accurate estimates of CO compared with echocardiography. PMID:25108554

Papaioannou, Theodore G; Soulis, Dimitrios; Vardoulis, Orestis; Protogerou, Athanase; Sfikakis, Petros P; Stergiopulos, Nikolaos; Stefanadis, Christodoulos

2014-10-01

78

Environmental risk assessments for transgenic crops producing output trait enzymes  

PubMed Central

The environmental risks from cultivating crops producing output trait enzymes can be rigorously assessed by testing conservative risk hypotheses of no harm to endpoints such as the abundance of wildlife, crop yield and the rate of degradation of crop residues in soil. These hypotheses can be tested with data from many sources, including evaluations of the agronomic performance and nutritional quality of the crop made during product development, and information from the scientific literature on the mode-of-action, taxonomic distribution and environmental fate of the enzyme. Few, if any, specific ecotoxicology or environmental fate studies are needed. The effective use of existing data means that regulatory decision-making, to which an environmental risk assessment provides essential information, is not unnecessarily complicated by evaluation of large amounts of new data that provide negligible improvement in the characterization of risk, and that may delay environmental benefits offered by transgenic crops containing output trait enzymes. PMID:19924556

Tuttle, Ann; Shore, Scott; Stone, Terry

2009-01-01

79

Environmental risk assessments for transgenic crops producing output trait enzymes  

Microsoft Academic Search

The environmental risks from cultivating crops producing output trait enzymes can be rigorously assessed by testing conservative\\u000a risk hypotheses of no harm to endpoints such as the abundance of wildlife, crop yield and the rate of degradation of crop\\u000a residues in soil. These hypotheses can be tested with data from many sources, including evaluations of the agronomic performance\\u000a and nutritional

Alan Raybould; Ann Tuttle; Scott Shore; Terry Stone

2010-01-01

80

Effect of measurement errors on cardiac output calculated with O 2 and modified CO 2 Fick methods  

Microsoft Academic Search

We have investigated the effect of measurement errors on cardiac output, calculated via three different Fick methods. In method\\u000a 1, the classic O2 Fick equation is expressed in terms of oxygen uptake (\\u000a $$\\\\dot Vo_2 $$\\u000a ), arterial pulse (Sao2) and venous oximetry (Svo2) saturations. The second method, a modified CO2 Fick method, is obtained by replacing\\u000a $$\\\\dot Vo_2 $$

C. Kees Mahutte; Michael B. Jaffe

1995-01-01

81

High-output cardiac failure in a fetus with thanatophoric dysplasia associated with large placental chorioangioma: case report.  

PubMed

Placental chorioangioma is an angioma arising from chorionic tissue. Fetal thanatophoric dysplasia is a lethal skeletal dysplasia due to mutation of fibroblast growth factor receptor 3 gene. These two conditions are rare and their coexistence in a given fetus is even rarer. We present a case of a fetus with thanatophoric dysplasia having high-output cardiac failure due to a large placental chorioangioma. PMID:22508320

Akercan, Fuat; Oncul Seyfettinoglu, Sevtap; Zeybek, Burak; Cirpan, Teksin

2012-05-01

82

Non-invasive cardiac output evaluation during a maximal progressive exercise test, using a new impedance cardiograph device  

Microsoft Academic Search

.   One of the greatest challenges in exercise physiology is to develop a valid, reliable, non-invasive and affordable measurement\\u000a of cardiac output (CO). The purpose of this study was to evaluate the reproducibility and accuracy of a new impedance cardiograph\\u000a device, the Physio Flow, during a 1-min step incremental exercise test from rest to maximal peak effort. A group of

Ruddy Richard; Evelyne Lonsdorfer-Wolf; Anne Charloux; Stéphane Doutreleau; Martin Buchheit; Monique Oswald-Mammosser; Eliane Lampert; Bertrand Mettauer; Bernard Geny; Jean Lonsdorfer

2001-01-01

83

Dynamic device properties of pulse contour cardiac output during transcatheter aortic valve implantation.  

PubMed

This prospective single-center study aimed to determine the responsiveness and diagnostic performance of continuous cardiac output (CCO) monitors based on pulse contour analysis compared with invasive mean arterial pressure (MAP) during predefined periods of acute circulatory deterioration in patients undergoing transcatheter aortic valve implantation (TAVI). The ability of calibrated (CCOCAL) and self-calibrated (CCOAUTOCAL) pulse contour analysis to detect the hemodynamic response to 37 episodes of balloon aortic valvuloplasty enabled by rapid ventricular pacing was quantified in 13 patients undergoing TAVI. A "low" and a "high" cut-off limit were predefined as a 15 or 25 % decrease from baseline respectively. We found no significant differences between CCOCAL and MAP regarding mean response time [low cut-off: 8.6 (7.1-10.5) vs. 8.9 (7.3-10.8) s, p = 0.76; high cut-off: 11.4 (9.7-13.5) vs. 12.6 (10.7-14.9) s, p = 0.32] or diagnostic performance [area under the receiver operating characteristics curve (AUC): 0.99 (0.98-1.0) vs. 1.0 (0.99-1.0), p = 0.46]. But CCOCAL had a significantly higher amplitude response [95.0 (88.7-98.8) % decrease from baseline] than MAP [41.2 (30.0-52.9) %, p < 0.001]. CCOAUTOCAL had a significantly lower AUC [0.83 (0.73-0.93), p < 0.001] than MAP. Moreover, CCOCAL detected hemodynamic recovery significantly earlier than MAP. In conclusion, CCOCAL and MAP provided equivalent responsiveness and diagnostic performance to detect acute circulatory depression, whereas CCOAUTOCAL appeared to be less appropriate. In contrast to CCOCAL the amplitude response of MAP was poor. Consequently even small response amplitudes of MAP could indicate severe decreases in CO. PMID:25355556

Petzoldt, Martin; Riedel, Carsten; Braeunig, Jan; Haas, Sebastian; Goepfert, Matthias S; Treede, Hendrik; Baldus, Stephan; Goetz, Alwin E; Reuter, Daniel A

2014-10-30

84

Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon.  

PubMed

Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air-breathing organ (ABO). We examined changes in cardiac output (V(b)) associated with increases in air-breathing that accompany exercise and aquatic hypoxia. Juvenile (0.49 kg) and adult (1.21 kg) tarpon were allowed to recover in a swim flume at 27 degrees C after being instrumented with a Doppler flow probe around the ventral aorta to monitor V(b) and with a fibre-optic oxygen sensor in the ABO to monitor air-breathing frequency. Under normoxic conditions and in both juveniles and adults, routine air-breathing frequency was 0.03 breaths min(-1) and V(b) was about 15 mL min(-1) kg(-1). Normoxic exercise (swimming at about 1.1 body lengths s(-1)) increased air-breathing frequency by 8-fold in both groups (reaching 0.23 breaths min(-1)) and increased V(b) by 3-fold for juveniles and 2-fold for adults. Hypoxic exposure (2 kPa O2) at rest increased air-breathing frequency 19-fold (to around 0.53 breaths min(-1)) in both groups, and while V(b) again increased 3-fold in resting juvenile fish, V(b) was unchanged in resting adult fish. Exercise in hypoxia increased air-breathing frequency 35-fold (to 0.95 breaths min(-1)) in comparison with resting normoxic fish. While juvenile fish increased V(b) nearly 2-fold with exercise in hypoxia, adult fish maintained the same V(b) irrespective of exercise state and became agitated in comparison. These results imply that air-breathing during exercise and hypoxia can benefit oxygen delivery, but to differing degrees in juvenile and adult tarpon. We discuss this difference in the context of myocardial oxygen supply. PMID:17869150

Clark, T D; Seymour, R S; Christian, K; Wells, R M G; Baldwin, J; Farrell, A P

2007-11-01

85

Evaluation of a noninvasive continuous cardiac output monitoring system based on thoracic bioreactance.  

PubMed

Noninvasive cardiac output (CO) measurement can be useful in many clinical settings where invasive monitoring is not desired. Bioimpedance (intrabeat measurement of changes in transthoracic voltage amplitude in response to an injected high-frequency current) has been explored for this purpose but is limited in some clinical settings because of inherently low signal-to-noise ratio. Since changes in fluid content also induce changes in thoracic capacitive and inductive properties, we tested whether a noninvasive CO measurement could be obtained through measurement of the relative phase shift of an injected current (i.e., bioreactance). We constructed a prototype device that applies a 75-kHz current and determines the relative phase shift (dPhi/dt) of the recorded transthoracic voltage. CO was related to the product of peak dPhi/dt, heart rate, and ventricular ejection time. The preclinical study was done in nine open-chest pigs put on right heart bypass so that CO could be varied at known values. This was followed by a feasibility study in 27 postoperative patients who had a Swan-Ganz catheter (SGC). The measurements of noninvasive CO measurement and cardiopulmonary bypass pump correlated to each other (r = 0.84) despite the large variation in CO and temperatures. Similarly, in patients, mean CO values were 5.18 and 5.17 l/min as measured by SGC and the noninvasive CO measurement system, respectively, and were highly correlated over the range of values studied (r = 0.90). Preclinical and clinical data demonstrate the feasibility of using blood flow-related phase shifts of transthoracic electric signals to perform noninvasive continuous CO monitoring. PMID:17384132

Keren, Hanan; Burkhoff, Daniel; Squara, Pierre

2007-07-01

86

Diesel exhaust inhalation increases cardiac output, bradyarrhythmias, and parasympathetic tone in aged heart failure-prone rats.  

PubMed

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel engine exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance of normal cardiac function. To explore this putative mechanism, we examined cardiophysiologic responses to DE inhalation in a model of aged heart failure-prone rats without signs or symptoms of overt heart failure. We hypothesized that acute DE exposure would alter heart rhythm, cardiac electrophysiology, and ventricular performance and dimensions consistent with autonomic imbalance while increasing biochemical markers of toxicity. Spontaneously hypertensive heart failure rats (16 months) were exposed once to whole DE (4h, target PM(2.5) concentration: 500 µg/m(3)) or filtered air. DE increased multiple heart rate variability (HRV) parameters during exposure. In the 4h after exposure, DE increased cardiac output, left ventricular volume (end diastolic and systolic), stroke volume, HRV, and atrioventricular block arrhythmias while increasing electrocardiographic measures of ventricular repolarization (i.e., ST and T amplitudes, ST area, T-peak to T-end duration). DE did not affect heart rate relative to air. Changes in HRV positively correlated with postexposure changes in bradyarrhythmia frequency, repolarization, and echocardiographic parameters. At 24h postexposure, DE-exposed rats had increased serum C-reactive protein and pulmonary eosinophils. This study demonstrates that cardiac effects of DE inhalation are likely to occur through changes in autonomic balance associated with modulation of cardiac electrophysiology and mechanical function and may offer insights into the adverse health effects of traffic-related air pollutants. PMID:23047911

Carll, Alex P; Lust, Robert M; Hazari, Mehdi S; Perez, Christina M; Krantz, Quentin Todd; King, Charly J; Winsett, Darrell W; Cascio, Wayne E; Costa, Daniel L; Farraj, Aimen K

2013-02-01

87

Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure–Prone Rats  

PubMed Central

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel engine exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance of normal cardiac function. To explore this putative mechanism, we examined cardiophysiologic responses to DE inhalation in a model of aged heart failure–prone rats without signs or symptoms of overt heart failure. We hypothesized that acute DE exposure would alter heart rhythm, cardiac electrophysiology, and ventricular performance and dimensions consistent with autonomic imbalance while increasing biochemical markers of toxicity. Spontaneously hypertensive heart failure rats (16 months) were exposed once to whole DE (4h, target PM2.5 concentration: 500 µg/m3) or filtered air. DE increased multiple heart rate variability (HRV) parameters during exposure. In the 4h after exposure, DE increased cardiac output, left ventricular volume (end diastolic and systolic), stroke volume, HRV, and atrioventricular block arrhythmias while increasing electrocardiographic measures of ventricular repolarization (i.e., ST and T amplitudes, ST area, T-peak to T-end duration). DE did not affect heart rate relative to air. Changes in HRV positively correlated with postexposure changes in bradyarrhythmia frequency, repolarization, and echocardiographic parameters. At 24h postexposure, DE-exposed rats had increased serum C-reactive protein and pulmonary eosinophils. This study demonstrates that cardiac effects of DE inhalation are likely to occur through changes in autonomic balance associated with modulation of cardiac electrophysiology and mechanical function and may offer insights into the adverse health effects of traffic-related air pollutants. PMID:23047911

Farraj, Aimen K.

2013-01-01

88

Treatment of high output cardiac failure by flow-adapted hepatic artery banding (FHAB) in patients with hereditary hemorrhagic telangiectasia.  

PubMed

Involvement of abdominal organs in Osler's disease may lead to the development of hepatic arteriovenous shunts with a dilatation of the hepatic artery. Right and subsequent global heart failure due to cardiac valvular insufficiency, pulmonary artery hypertension, and hepatomegaly as well as increased cardiac output may result. This hyperdynamic hepatic blood flow can be reduced by ligature or banding of the hepatic artery or by orthotopic liver transplantation. We report on two female patients suffering from Osler's disease (68 and 76 years old) with severe heart insufficiency (NYHA III-IV) caused by the high hepatic shunt volumes. A gradual banding of the hepatic artery directed by intraoperative flow measurement in the hepatic artery and control of the systemic hemodynamics by Swan-Ganz or COLD catheters was performed in these patients. The banding was achieved by encasing the hepatic artery in a PTFE cuff (length, 1.0 cm). The high cardiac output could be reduced from 11.2 to 7.0 l/min and from 10.7 to 6.0 l/min, respectively. The respective hepatic artery flow was reduced from 2.0 to 0.3 l/min and from 4.0 to 0.7 l/min. An improvement of heart insufficiency, a reduction in the severity of the cardiac valvular insufficiency, and a reduction of the pulmonary arterial hypertension could be already observed intraoperatively. One patient died of right cardiac failure after an orthotopic liver transplantation 7 months later. The other one died 3 years after the banding. The banding of the hepatic artery controlled by hepatic arterial flow measurement can be considered as an effective and safe palliative procedure in intrahepatic HHT compared to therapeutic alternatives such as hepatic artery ligation or embolization. PMID:18027057

Koscielny, A; Willinek, W A; Hirner, A; Wolff, M

2008-05-01

89

Effect of hemorrhage on cardiac output, vasopressin, aldosterone, and diuresis during immersion in men  

NASA Technical Reports Server (NTRS)

The purpose of this research was to test the hypotesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q(sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses. Eight men (19-23 yr) were supine during a 2-hr control period in air, and then sat for 5-hr test periods in air at 20 C (dry control, DC); water at 34.5 C (wet control, WC); and water (34.5 C) after hemorrhage (WH) of 14.8 plus or minus 0.3 percent of their blood volume. Blood volume was -11.6 plus or minus 0.6 percent at immersion (time 0). Mean (bar-X hrs 1-5) Q(sub co) was unchanged in WC (5.3 plus or minus 0.01 l/min) and in WH (4.5 plus or minus 0.1 l/min), but decreased (P less than 0.05) in DC to 3.6 plus or minus 0.1 l/min. Mean urine excretion rates were 1.0 plus or minus 0.2 ml/min for DC and 1.1 plus or minus 0.2 ml/min for WH; both were lower (P less than 0.05) than that for WC of 2.0 plus or minus 0.4 ml/min. Plasma (Na+) and (Osm) were unchanged in all experiments. Mean plasma vasopressin (PVP) (bar-X hrs 1-5) was 1.1 plus or minus 0.1 pg/ml in WC, and higher (P less than 0.05) in DC (2.1 plus or minus 0.2 pg/ml)and WH (2.1 plus or minus 0.1 pg/ml); it was unchanged during air and water test periods. Thus, hemorrhage attenuated the immersion-induced increase in Q(sub co), eliminated the WC diuresis, maintained plasma renin activity and PVP at DC levels and did not change immersion-induced aldosterone suppression; the osmotic diuresis during control immersion is apparently not due to either aldosterone suppression or vasopressin suppression.

Greenleaf, J. E.; Simanonok, K.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

1992-01-01

90

Blunted frequency-dependent upregulation of cardiac output is related to impaired relaxation in diastolic heart failure  

PubMed Central

Aims We tested the hypothesis that, in heart failure with normal ejection fraction (HFNEF), diastolic dysfunction is accentuated at increasing heart rates, and this contributes to impaired frequency-dependent augmentation of cardiac output. Methods and results In 17 patients with HFNEF (median age 69 years, 13 female) and seven age-matched control patients, systolic and diastolic function was analysed by pressure–volume loops at baseline heart rate and during atrial pacing to 100 and 120 min?1. At baseline, relaxation was prolonged and end-diastolic left ventricular stiffness was higher in HFNEF, whereas all parameters of systolic function were not different from control patients. This resulted in smaller end-diastolic volumes, higher end-diastolic pressure, and a lower stroke volume and cardiac index in HFNEF vs. control patients. During pacing, frequency-dependent upregulation of contractility indices (+dP/dtmax and Ees) occurred similarly in HFNEF and control patients, but frequency-dependent acceleration of relaxation (dP/dtmin) was blunted in HFNEF. In HFNEF, end-diastolic volume and stroke volume decreased with higher heart rates while both remained unchanged in control patients. Conclusion In HFNEF, frequency-dependent upregulation of cardiac output is blunted. This results from progressive volume unloading of the left ventricle due to limited relaxation reserve in combination with increased LV passive stiffness, despite preserved force–frequency relation. PMID:19720638

Wachter, Rolf; Schmidt-Schweda, Stephan; Westermann, Dirk; Post, Heiner; Edelmann, Frank; Kasner, Mario; Lüers, Claus; Steendijk, Paul; Hasenfuß, Gerd; Tschöpe, Carsten; Pieske, Burkert

2009-01-01

91

Assessment of Cardiac Sarcoidosis with Advanced Imaging Modalities  

PubMed Central

Sarcoidosis is a chronic systemic disease of unknown etiology that is characterized by the presence of noncaseating epithelioid granulomas, usually in multiple organs. Several studies have shown that sarcoidosis might be the result of an exaggerated granulomatous reaction after exposure to unidentified antigens in genetically susceptible individuals. Cardiac involvement may occur and lead to an adverse outcome: the heart mechanics will be affected and that causes ventricular failure, and the cardiac electrical system will be disrupted and lead to third degree atrioventricular block, malignant ventricular tachycardia, and sudden cardiac death. Thus, early diagnosis and treatment of this potentially devastating disease is critically important. However, sensitive and accurate imaging modalities have not been established. Recent studies have demonstrated the promising potential of cardiac magnetic resonance imaging (MRI) and 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) in the diagnosis and assessment of cardiac sarcoidosis (CS). In this review, we discuss the epidemiology, etiology, histological findings, and clinical features of sarcoidosis. We also introduce advanced imaging including 18F-FDG PET and cardiac MRI as more reliable diagnostic modalities for CS. PMID:25250336

Akasaka, Takashi

2014-01-01

92

Reliability of continuous cardiac output measurement during intra-abdominal hypertension relies on repeated calibrations: an experimental animal study  

PubMed Central

Introduction Monitoring cardiac output (CO) may allow early detection of haemodynamic instability, aiming to reduce morbidity and mortality in critically ill patients. Continuous cardiac output (CCO) monitoring is recommended in septic or postoperative patients with high incidences of intra-abdominal hypertension (IAH). The aim of the present study was to compare the agreement between three CCO methods and a bolus thermodilution CO technique during acute IAH and volume loading. Methods Ten pigs were anaesthetised and instrumented for haemodynamic measurements. Cardiac output was obtained using CCO by pulse power analysis (PulseCO; LiDCO monitor), using CCO by pulse contour analysis (PCCO; PiCCO monitor) and using CCO by pulmonary artery catheter thermodilution (CCOPAC), and was compared with bolus transcardiopulmonary thermodilution CO (COTCP) at baseline, after fluid loading, at IAH and after an additional fluid loading at IAH. Whereas PulseCO was only calibrated at baseline, PCCO was calibrated at each experimental step. Results PulseCO and PCCO underestimated CO, as the overall bias ± standard deviation was 1.0 ± 1.5 l/min and 1.0 ± 1.1 l/min compared with COTCP. A clinically accepted agreement between all of the CCO methods and COTCP was observed only at baseline. Whereas IAH did not influence the CO, increased CO following fluid loading at IAH was only reflected by CCOPAC and COTCP, not by uncalibrated PulseCO and PCCO. After recalibration, PCCO was comparable with COTCP. Conclusions The CO obtained by uncalibrated PulseCO and PCCO failed to agree with COTCP during IAH and fluid loading. In the critically ill patient, recalibration of continuous arterial waveform CO methods should be performed after fluid loading or before a major change in therapy is initiated. PMID:18957114

Gruenewald, Matthias; Renner, Jochen; Meybohm, Patrick; Höcker, Jan; Scholz, Jens; Bein, Berthold

2008-01-01

93

Clinical review: Guyton - the role of mean circulatory filling pressure and right atrial pressure in controlling cardiac output  

PubMed Central

Arthur Guyton's concepts of the determinative role of right heart filling in cardiac output continue to be controversial. This paper reviews his seminal experiments in detail and clarifies the often confusing concepts underpinning his model. One primary criticism of Guyton's model is that the parameters describing venous return had not been measured in a functioning cardiovascular system in humans. Thus, concerns have been expressed in regard to the ability of Guyton's simplistic model, with few parameters, to model the complex human circulation. Further concerns have been raised in regard to the artificial experimental preparations that Guyton used. Recently reported measurements in humans support Guyton's theoretical and animal work. PMID:21144008

2010-01-01

94

Femoral Blood Flow and Cardiac Output During Blood Flow Restricted Leg Press Exercise  

NASA Technical Reports Server (NTRS)

Low load blood flow restricted resistance exercise (LBFR) causes muscle hypertrophy that may be stimulated by the local ischemic environment created by the cuff pressure. However, local blood flow (BF) during such exercise is not well understood. PURPOSE: To characterize femoral artery BF and cardiac output (CO) during leg press exercise (LP) performed at a high load (HL) and low load (LL) with different levels of cuff pressure. METHODS: Eleven subjects (men/women 4/7, age 31.4+/-12.8 y, weight 68.9+/-13.2 kg, mean+/-SD) performed 3 sets of supine left LP to fatigue with 90 s of rest in 4 conditions: HL (%1-RM/cuff pressure: 80%/0); LL (20%/0); LBFR(sub DBP) (20%/1.3 x diastolic blood pressure, BP); LBFR(sub SBP) (20%/1.3 x supine systolic BP). The cuff remained inflated throughout the LBFR exercise sessions. Artery diameter, velocity time integral (VTI), and stroke volume (SV) were measured using Doppler ultrasound at rest and immediately after each set of exercise. Heart rate (HR) was monitored using a 3-lead ECG. BF was calculated as VTI x vessel cross-sectional area. CO was calculated as HR x SV. The data obtained after each set of exercise were averaged and used for analyses. Multi-level modeling was used to determine the effect of exercise condition on dependent variables. Statistical significance was set a priori at p< 0.05. RESULTS: Artery diameter did not change from baseline. BF increased (p<0.05) after exercise in each condition except LBFR(sub SBP) in the order of HL (12.73+/-1.42 cm3,mean+/-SE) > LL (9.92+/-0.82 cm3) > LBFR(sub dBP)(6.47+/-0.79 cm3) > LBFR(sub SBP) (3.51+/-0.59 cm3). Blunted exercise induced increases occurred in HR, SV, and CO after LBFR compared to HL and LL. HR increased 45% after HL and LL and 28% after LBFR (p<0.05), but SV increased (p<0.05) only after HL. Consequently, the increase (p<0.05) in CO was greater in HL and LL (approximately 3 L/min) than in LBFR (approximately 1 L/min). CONCLUSION: BF during LBFR(sub SBP) was 1/3 of that observed in LL, which supports the hypothesis that local ischemia stimulates the LBFR hypertrophic response. As the cuff did not compress the artery, the ischemia may have occurred because of the blunted rise in CO or because arterial BP cannot overcome the cuff pressure. As LBFR(sub DBP) effectively reduced BF and CO with cuff pressures less than systolic BP, future studies should investigate the hypertrophic potential of LBFR at even lower cuff pressures.

Everett, M. E.; Hackney, K.; Ploutz-Snyder, L.

2011-01-01

95

Cardiac causes of pulmonary arterial hypertension: assessment with multidetector CT  

Microsoft Academic Search

The causes of pulmonary arterial hypertension (PAH) are diverse and include multiple congenital and acquired cardiac diseases\\u000a as well as diseases primarily affecting the pulmonary vasculature, lung, pleura and chest wall. The traditional role of CT\\u000a in evaluating PAH includes assessment of pulmonary vasculature and lung parenchyma with limited assessment of the heart. Advances\\u000a in multidetector CT technology with improved

Edward T. D. Hoey; Deepa Gopalan; S. K. Bobby Agrawal; Nicholas J. Screaton

2009-01-01

96

The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia  

PubMed Central

Objective: The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared. Results: The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001). Conclusion: In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations. PMID:24772126

Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

2014-01-01

97

[Regulation of cardiac output;an approximation at 3 levels: organic, cellular, and protein].  

PubMed

The heart is the central point for adaptation of the organism to physical exercise because it is the center of the energy support system. Its activity is regulated at three levels; organ, cells and molecular and genetic components. During the development of the heart, the organ adapts in response to chronic and acute overloads by instantaneous functional and chronic changes, leading to a variable degree of cardiac growth. Physical exercise (acute and chronic) is the main example of physiologic overload. The acute response of the heart means a mechanical-hemodynamical and energetic modulation, driving to a final point where oxygen supply fits the increased need. Training, as response to chronic exercise, promotes an increase in energetic capacity (heart rate and stroke volume), structurally reflected in the physiological cardiac hypertrophy. Global functional and structural changes express what is happening at the cellular level. Different stimuli signal through specific receptors and second messengers to the nucleus, regulating gene expression and conditioning structural (size) and functional (contractile) changes. Changes in cellular size explain, by Starling mechanism, the increase in individual contractile strength and in reduction of the ventricular cavity in the systolic period. Other structural changes refer to the interstitium, myocardial vasculature and vascular reactivity. Changes in contractility affect the composition of the contractile elements (isoforms of heavy myosin, light myosin and/or modulatory proteins) and sarcoplasmic Ca2+ regulation, through the increase in Ca2+ flow. Many of the adaptations to chronic exercise studied in vivo in intact heart, isolated heart (Langendorf) or papillary muscle (multicellular preparation), are retained in the cardiomyocyte. Isolated cardiomyocytes can be precisely through the medium, temperature, ionic composition, active substances, etc. Shortening speed without load (Vmax), considered an inotropic index (Sonnenblick) can be measured independently of the initial length. Myocytes shorten against an internal load (restoration force) with viscous and elastic components, although they cannot be loaded externally (stretching is difficult). Cardiomyocyte isolation and maintenance requires strict and controlled conditions. This model offers many possibilities for studying dimensions, contraction-relaxation mechanics, Ca2+ and pH dynamics, beta-adrenergic receptors, electrophysiology, pharmacology, genetics, etc. This kind of studies can deal with normal myocytes or myocytes from trained animals, cardiomyopathies, etc. PMID:10386344

Martíenz Caro, D; Rodríguez García, J A; Munguía, L

1999-01-01

98

Measurement of cardiac output in children by pressure-recording analytical method.  

PubMed

We evaluated two pressure-recording analytical method (PRAM) software versions (v.1 and v.2) to measure cardiac index (CI) in hemodynamically stable critically ill children and investigate factors that influence PRAM values. The working hypothesis was that PRAM CI measurements would stay within normal limits in hemodynamically stable patients. Ninety-five CI PRAM measurements were analyzed in 47 patients aged 1-168 months. Mean CI was 4.1 ± 1.4 L/min/m(2) (range 2.0-7.0). CI was outside limits defined as normal (3-5 L/min/m(2)) in 53.7 % of measurements (47.8 % with software v.1 and 69.2 % with software v.2, p = 0.062). Moreover, 14.7 % of measurements were below 2.5 L/min/m(2), and 13.6 % were above 6 L/min/m(2). CI was significantly lower in patients with a clearly visible dicrotic notch than in those without (3.7 vs. 4.6 L/min/m(2), p = 0.004) and in children with a radial arterial catheter (3.5 L/min/m(2)) than in those with a brachial (4.4 L/min/m(2), p = 0.021) or femoral catheter (4.7 L/min/m(2), p = 0.005). By contrast, CI was significantly higher in children under 12 months (4.2 vs. 3.6 L/min/m(2), p = 0.034) and weighing under 10 kg (4.2 vs. 3.6 L/min/m(2), p = 0.026). No significant differences were observed between cardiac surgery patients and the rest of children. A high percentage of CI measurements registered by PRAM were outside normal limits in hemodynamically stable, critically ill children. CI measured by PRAM may be influenced by the age, weight, location of catheter, and presence of a dicrotic notch. PMID:25179459

Urbano, Javier; López, Jorge; González, Rafael; Solana, María José; Fernández, Sarah N; Bellón, José M; López-Herce, Jesús

2015-02-01

99

Variations in arterial blood pressure are associated with parallel changes in FlowTrac\\/Vigileo®-derived cardiac output measurements: a prospective comparison study  

Microsoft Academic Search

ABSTRACT: INTRODUCTION: The reliability of autocalibrated pressure waveform analysis by the FloTrac-Vigileo® (FTV) system for the determination of cardiac output in comparison with intermittent pulmonary arterial thermodilution (IPATD) is controversial. The present prospective comparison study was designed to determine the effects of variations in arterial blood pressure on the reliability of the FTV system in patients undergoing coronary artery bypass

Savvas Eleftheriadis; Zisis Galatoudis; Vasilios Didilis; Ioannis Bougioukas; Julika Schön; Hermann Heinze; Klaus-Ulrich Berger; Matthias Heringlake

2009-01-01

100

Influence of dobutamine and dopamine on hemodynamics and plasma concentrations of noradrenaline and renin in patients with low cardiac output following acute myocardial infarction  

Microsoft Academic Search

The comparative hemodynamic effects of dobutamine and dopamine were studied in 6 patients with low cardiac output resulting from acute myocardial infarction. Plasma levels of noradrenaline and renin were measured before and during a 5 µg\\/kg\\/min infusion of each of the drugs. Dobutamine had a more pronounced chronotropic effect, increased the systolic arterial pressure more and decreased the systemic vascular

T. L. Kho; J. W. Henquet; R. Punt; W. H. Birkenhäger; K. H. Rahn

1980-01-01

101

Cardiac-respiratory self-gated cine ultra-short echo time (UTE) cardiovascular magnetic resonance for assessment of functional cardiac parameters at high magnetic fields  

PubMed Central

Background To overcome flow and electrocardiogram-trigger artifacts in cardiovascular magnetic resonance (CMR), we have implemented a cardiac and respiratory self-gated cine ultra-short echo time (UTE) sequence. We have assessed its performance in healthy mice by comparing the results with those obtained with a self-gated cine fast low angle shot (FLASH) sequence and with echocardiography. Methods 2D self-gated cine UTE (TE/TR?=?314 ?s/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 5 min 5 sec) and self-gated cine FLASH (TE/TR?=?3 ms/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 4 min 49 sec) images were acquired at 9.4 T. Volume of the left and right ventricular (LV, RV) myocardium as well as the end-diastolic and -systolic volume was segmented manually in MR images and myocardial mass, stroke volume (SV), ejection fraction (EF) and cardiac output (CO) were determined. Statistical differences were analyzed by using Student t test and Bland-Altman analyses. Results Self-gated cine UTE provided high quality images with high contrast-to-noise ratio (CNR) also for the RV myocardium (CNRblood-myocardium?=?25.5?±?7.8). Compared to cine FLASH, susceptibility, motion, and flow artifacts were considerably reduced due to the short TE of 314 ?s. The aortic valve was clearly discernible over the entire cardiac cycle. Myocardial mass, SV, EF and CO determined by self-gated UTE were identical to the values measured with self-gated FLASH and showed good agreement to the results obtained by echocardiography. Conclusions Self-gated UTE allows for robust measurement of cardiac parameters of diagnostic interest. Image quality is superior to self-gated FLASH, rendering the method a powerful alternative for the assessment of cardiac function at high magnetic fields. PMID:23826850

2013-01-01

102

Estimation of cardiac output and systemic vascular resistance using a multivariate regression model with features selected from the finger photoplethysmogram and routine cardiovascular measurements  

PubMed Central

Background Cardiac output (CO) and systemic vascular resistance (SVR) are two important parameters of the cardiovascular system. The ability to measure these parameters continuously and noninvasively may assist in diagnosing and monitoring patients with suspected cardiovascular diseases, or other critical illnesses. In this study, a method is proposed to estimate both the CO and SVR of a heterogeneous cohort of intensive care unit patients (N=48). Methods Spectral and morphological features were extracted from the finger photoplethysmogram, and added to heart rate and mean arterial pressure as input features to a multivariate regression model to estimate CO and SVR. A stepwise feature search algorithm was employed to select statistically significant features. Leave-one-out cross validation was used to assess the generalized model performance. The degree of agreement between the estimation method and the gold standard was assessed using Bland-Altman analysis. Results The Bland-Altman bias ±precision (1.96 times standard deviation) for CO was -0.01 ±2.70 L min-1 when only photoplethysmogram (PPG) features were used, and for SVR was -0.87 ±412 dyn.s.cm-5 when only one PPG variability feature was used. Conclusions These promising results indicate the feasibility of using the method described as a non-invasive preliminary diagnostic tool in supervised or unsupervised clinical settings. PMID:23452705

2013-01-01

103

Cardiac output by Doppler echocardiography in the premature baboon: Comparison with radiolabeled microspheres  

SciTech Connect

Pulsed-Doppler echocardiography (PDE) is a useful noninvasive method for determining left ventricular output (LVO). However, despite increasingly widespread use in neonatal intensive care units, validation studies in prematures with cardiopulmonary disease are lacking. The purpose of this study was to compare radiolabeled microsphere (RLM) and PDE measurements of LVO, using the critically ill premature baboon as a model of the human neonate. Twenty-two paired RLM and PDE measurements of LVO were obtained in 14 animals between 3 and 24 h of age. Average PDE LVO was 152 ml/min/kg (range, 40-258 ml/min/kg) compared to 158 ml/min/kg (range, 67-278 ml/min/kg) measured by RLM. Linear regression analysis of the paired measurements showed good correlation with a slope near unity (gamma = 0.94x + 4.20, r = 0.91, SEE = 25.7 ml). The authors conclude that PDE determinations of LVO compare well with those measured by RLM in the premature baboon. PDE appears to provide a valid estimate of LVO and should be useful in human prematures with cardiopulmonary distress.

Kinsella, J.P.; Morrow, W.R.; Gerstmann, D.R.; Taylor, A.F.; deLemos, R.A. (Wilford Hall U.S.A.F. Medical Center, San Antonio, TX (USA))

1991-04-01

104

Role of frailty assessment in patients undergoing cardiac interventions  

PubMed Central

Average life expectancy is increasing in the western world resulting in a growing number of frail individuals with coronary heart disease, often associated with comorbidities. Decisions to proceed to invasive interventions in elderly frail patients is challenging because they may gain benefit, but are also at risk of procedure-related complications. Current risk scores designed to predict mortality in cardiac procedures are mainly based on clinical and angiographic factors, with limitations in the elderly because they are mainly derived from a middle-aged population, do not account for frailty and do not predict the impact of the procedure on quality of life which often matters more to elderly patients than mortality. Frailty assessment has emerged as a measure of biological age that correlates well with quality of life, hospital admissions and mortality. Potentially, the incorporation of frailty into current risk assessment models will cause a shift towards more appropriate care. The need for a more accurate method of risk stratification incorporating frailty, particularly for elderly patients is pressing. This article reviews the association between frailty and cardiovascular disease, the impact of frailty on outcomes of cardiac interventions and suggests ways in which frailty assessment could be incorporated into cardiology clinical practice. PMID:25332792

Rowe, Rebecca; Iqbal, Javaid; Murali-krishnan, Rachel; Sultan, Ayyaz; Orme, Rachel; Briffa, Norman; Denvir, Martin; Gunn, Julian

2014-01-01

105

Assessing thermalization and estimating the Hamiltonian with output data only  

SciTech Connect

I consider the generic situation where a finite number of identical test systems in varying (possibly unknown) initial states are subjected independently to the same unknown process. I show how one can infer from the output data alone whether the process in question induces thermalization and, if so, which constants of the motion characterize the final equilibrium states. In case thermalization does occur and there is no evidence for constants of the motion other than energy, I further show how the same output data can be used to estimate the test systems' effective Hamiltonian. For both inference tasks I devise a statistical framework inspired by the generic techniques of factor and principal component analysis. I illustrate its use in the simple example of qubits.

Rau, Jochen [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany)

2011-11-15

106

Nationwide assessment of potential output from wind-powered generators  

NASA Technical Reports Server (NTRS)

A method for computing the actual expected power for a wind-powered generator from a given observed speed distribution is described and applied to estimate the potential output for different locations in the continental U.S. A contour map of generator capacity factor values (fraction of the rated output realizable) is obtained for wind-powered generator systems with a cut-in speed of 3.6 m/sec and a rated speed of 8.0 m/sec, and for a unit with hypothetical values for the 1 MW class (cut-in speed, 6.7 m/sec; rated speed, 13.4 m/sec). Results indicate that in the central U.S. and in certain areas of the New England coast at a height of 61 m, over 60% of the rated output power could be obtained on an annual average. In these areas capacity factors of over 20% could be obtained with the 1MW system.

Justus, C. G.; Hargraves, W. R.; Yalcin, A.

1976-01-01

107

Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure-Prone Rats  

EPA Science Inventory

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance...

108

Downscaling climate model output for water resources impacts assessment (Invited)  

NASA Astrophysics Data System (ADS)

Water agencies in the U.S. and around the globe are beginning to wrap climate change projections into their planning procedures, recognizing that ongoing human-induced changes to hydrology can affect water management in significant ways. Future hydrology changes are derived using global climate model (GCM) projections, though their output is at a spatial scale that is too coarse to meet the needs of those concerned with local and regional impacts. Those investigating local impacts have employed a range of techniques for downscaling, the process of translating GCM output to a more locally-relevant spatial scale. Recent projects have produced libraries of publicly-available downscaled climate projections, enabling managers, researchers and others to focus on impacts studies, drawing from a shared pool of fine-scale climate data. Besides the obvious advantage to data users, who no longer need to develop expertise in downscaling prior to examining impacts, the use of the downscaled data by hundreds of people has allowed a crowdsourcing approach to examining the data. The wide variety of applications employed by different users has revealed characteristics not discovered during the initial data set production. This has led to a deeper look at the downscaling methods, including the assumptions and effect of bias correction of GCM output. Here new findings are presented related to the assumption of stationarity in the relationships between large- and fine-scale climate, as well as the impact of quantile mapping bias correction on precipitation trends. The validity of these assumptions can influence the interpretations of impacts studies using data derived using these standard statistical methods and help point the way to improved methods.

Maurer, E. P.; Pierce, D. W.; Cayan, D. R.

2013-12-01

109

The 24 h pattern of arterial pressure in mice is determined mainly by heart rate?driven variation in cardiac output  

PubMed Central

Abstract Few studies have systematically investigated whether daily patterns of arterial blood pressure over 24 h are mediated by changes in cardiac output, peripheral resistance, or both. Understanding the hemodynamic mechanisms that determine the 24 h patterns of blood pressure may lead to a better understanding of how such patterns become disturbed in hypertension and influence risk for cardiovascular events. In conscious, unrestrained C57BL/6J mice, we investigated whether the 24 h pattern of arterial blood pressure is determined by variation in cardiac output, systemic vascular resistance, or both and also whether variations in cardiac output are mediated by variations in heart rate and or stroke volume. As expected, arterial pressure and locomotor activity were significantly (P < 0.05) higher during the nighttime period compared with the daytime period when mice are typically sleeping (+12.5 ± 1.0 mmHg, [13%] and +7.7 ± 1.3 activity counts, [254%], respectively). The higher arterial pressure during the nighttime period was mediated by higher cardiac output (+2.6 ± 0.3 mL/min, [26%], P < 0.05) in association with lower peripheral resistance (?1.5 ± 0.3 mmHg/mL/min, [?13%] P < 0.05). The increased cardiac output during the nighttime was mainly mediated by increased heart rate (+80.0 ± 16.5 beats/min, [18%] P < 0.05), as stroke volume increased minimally at night (+1.6 ± 0.5 ?L per beat, [6%] P < 0.05). These results indicate that in C57BL/6J mice, the 24 h pattern of blood pressure is hemodynamically mediated primarily by the 24 h pattern of cardiac output which is almost entirely determined by the 24 h pattern of heart rate. These findings suggest that the differences in blood pressure between nighttime and daytime are mainly driven by differences in heart rate which are strongly correlated with differences in locomotor activity. PMID:25428952

Kurtz, Theodore W.; Lujan, Heidi L.; DiCarlo, Stephen E.

2014-01-01

110

Assessing neutron generator output using neutron activation of silicon  

NASA Astrophysics Data System (ADS)

D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the 28Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 × 10 3 n/s/cm 2 ± 5%, which is consistent with the manufacturer's specifications.

Kehayias, Pauli M.; Kehayias, Joseph J.

2007-08-01

111

Modifications to the accuracy assessment analysis routine MLTCRP to produce an output file  

NASA Technical Reports Server (NTRS)

Modifications are described that were made to the analysis program MLTCRP in the accuracy assessment software system to produce a disk output file. The output files produced by this modified program are used to aggregate data for regions greater than a single segment.

Carnes, J. G.

1978-01-01

112

How to assess prognosis after cardiac arrest and therapeutic hypothermia  

PubMed Central

The prognosis of patients who are admitted in a comatose state following successful resuscitation after cardiac arrest remains uncertain. Although the introduction of therapeutic hypothermia (TH) and improvements in post-resuscitation care have significantly increased the number of patients who are discharged home with minimal brain damage, short-term assessment of neurological outcome remains a challenge. The need for early and accurate prognostic predictors is crucial, especially since sedation and TH may alter the neurological examination and delay the recovery of motor response for several days. The development of additional tools, including electrophysiological examinations (electroencephalography and somatosensory evoked potentials), neuroimaging and chemical biomarkers, may help to evaluate the extent of brain injury in these patients. Given the extensive literature existing on this topic and the confounding effects of TH on the strength of these tools in outcome prognostication after cardiac arrest, the aim of this narrative review is to provide a practical approach to post-anoxic brain injury when TH is used. We also discuss when and how these tools could be combined with the neurological examination in a multimodal approach to improve outcome prediction in this population. PMID:24417885

2014-01-01

113

The effect of changes in cardiac output on middle cerebral artery mean blood velocity at rest and during exercise  

PubMed Central

We examined the relationship between changes in cardiac output and middle cerebral artery mean blood velocity (MCA Vmean) in seven healthy volunteer men at rest and during 50% maximal oxygen uptake steady-state submaximal cycling exercise. Reductions in were accomplished using lower body negative pressure (LBNP), while increases in were accomplished using infusions of 25% human serum albumin. Heart rate (HR), arterial blood pressure and MCA Vmean were continuously recorded. At each stage of LBNP and albumin infusion was measured using an acetylene rebreathing technique. Arterial blood samples were analysed for partial pressure of carbon dioxide tension (Pa,CO2. During exercise HR and were increased above rest (P < 0.001), while neither MCA Vmean nor Pa,CO2 was altered (P > 0.05). The MCA Vmean and were linearly related at rest (P < 0.001) and during exercise (P = 0.035). The slope of the regression relationship between MCA Vmean and at rest was greater (P = 0.035) than during exercise. In addition, the phase and gain between MCA Vmean and mean arterial pressure in the low frequency range were not altered from rest to exercise indicating that the cerebral autoregulation was maintained. These data suggest that the associated with the changes in central blood volume influence the MCA Vmean at rest and during exercise and its regulation is independent of cerebral autoregulation. It appears that the exercise induced sympathoexcitation and the change in the distribution of between the cerebral and the systemic circulation modifies the relationship between MCA Vmean and . PMID:16210355

Ogoh, Shigehiko; Brothers, R Matthew; Barnes, Quinton; Eubank, Wendy L; Hawkins, Megan N; Purkayastha, Sushmita; O-Yurvati, Albert; Raven, Peter B

2005-01-01

114

Pharmacokinetics, hemodynamic and metabolic effects of epinephrine to prevent post-operative low cardiac output syndrome in children  

PubMed Central

Introduction The response to exogenous epinephrine (Ep) is difficult to predict given the multitude of factors involved such as broad pharmacokinetic and pharmacodynamic between-subject variabilities, which may be more pronounced in children. We investigated the pharmacokinetics and pharmacodynamics of Ep, co-administered with milrinone, in children who underwent open heart surgical repair for congenital defects following cardiopulmonary bypass, including associated variability factors. Methods Thirty-nine children with a high risk of low cardiac output syndrome were prospectively enrolled. Ep pharmacokinetics, hemodynamic and metabolic effects were analyzed using the non-linear mixed effects modeling software MONOLIX. According to the final model, an Ep dosing simulation was suggested. Results Ep dosing infusions ranged from 0.01 to 0.23 ?g.kg-1.min-1 in children whose weight ranged from 2.5 to 58 kg. A one-compartment open model with linear elimination adequately described the Ep concentration-time courses. Bodyweight (BW) was the main covariate influencing clearance (CL) and endogenous Ep production rate (q0) via an allometric relationship: CL(BWi)?=??CL x (BWi)3/4 and q0(BWi)?=??q0 x (BWi )3/4. The increase in heart rate (HR) and mean arterial pressure (MAP) as a function of Ep concentration were well described using an Emax model. The effect of age was significant on HR and MAP basal level parameters. Assuming that Ep stimulated the production rate of plasma glucose, the increases in plasma glucose and lactate levels were well described by turnover models without any significant effect of age, BW or exogenous glucose supply. Conclusions According to this population analysis, the developmental effects of BW and age explained a part of the pharmacokinetic and pharmacodynamics between-subject variabilities of Ep administration in critically ill children. This approach ultimately leads to a valuable Ep dosing simulation which should help clinicians to determine an appropriate a priori dosing regimen. PMID:24456639

2014-01-01

115

PKPD modelling of the interrelationship between mean arterial BP, cardiac output and total peripheral resistance in conscious rats  

PubMed Central

Background and Purpose The homeostatic control of arterial BP is well understood with changes in BP resulting from changes in cardiac output (CO) and/or total peripheral resistance (TPR). A mechanism-based and quantitative analysis of drug effects on this interrelationship could provide a basis for the prediction of drug effects on BP. Hence, we aimed to develop a mechanism-based pharmacokinetic-pharmacodynamic (PKPD) model in rats that could be used to characterize the effects of cardiovascular drugs with different mechanisms of action (MoA) on the interrelationship between BP, CO and TPR. Experimental Approach The cardiovascular effects of six drugs with diverse MoA, (amlodipine, fasudil, enalapril, propranolol, hydrochlorothiazide and prazosin) were characterized in spontaneously hypertensive rats. The rats were chronically instrumented with ascending aortic flow probes and/or aortic catheters/radiotransmitters for continuous recording of CO and/or BP. Data were analysed in conjunction with independent information on the time course of drug concentration using a mechanism-based PKPD modelling approach. Key Results By simultaneous analysis of the effects of six different compounds, the dynamics of the interrelationship between BP, CO and TPR were quantified. System-specific parameters could be distinguished from drug-specific parameters indicating that the model developed is drug-independent. Conclusions and Implications A system-specific model characterizing the interrelationship between BP, CO and TPR was obtained, which can be used to quantify and predict the cardiovascular effects of a drug and to elucidate the MoA for novel compounds. Ultimately, the proposed PKPD model could be used to predict the effects of a particular drug on BP in humans based on preclinical data. PMID:23849040

Snelder, N; Ploeger, B A; Luttringer, O; Rigel, D F; Webb, R L; Feldman, D; Fu, F; Beil, M; Jin, L; Stanski, D R; Danhof, M

2013-01-01

116

Assessment of Cardiac Sympathetic Function with Iodine123-MIBG Imaging in Obstructive Sleep Apnea Syndrome  

Microsoft Academic Search

lodine-123-MIBG imaging has been used to evaluate myocardial sympathetic function in various cardiac diseases. In patients with obstructive sleep apnea syndrome (OSAS), increased sympathetic activity has been widely recognized, as assessed by measuring the plasma concentration and urinary excretion of catecholamines and by measuring muscle sympathetic nerve activity. However, these measurements are not specific indices of cardiac sympathetic function. Therefore,

Naoki Otsuka; Motoharu Ohi; Kazuo Chin; Hideo Kit; Tetsuo Noguchi; Tatsuhiko Hat; Ryuji Nohara; Ryohei Hosokawa; Masatoshi Fujita; Kenshi Kuno

117

Echocardiographic Assessment of Cardiac Morphology and Function in Xenopus  

PubMed Central

Advances using Xenopus as a model permit valuable inquiries into cardiac development from embryo to adult. Noninvasive methods are needed to study cardiac function longitudinally. The objective of this study was to evaluate the feasibility of echocardiographic studies in Xenopus and establish normative data of adult cardiac structure and function. Doppler and 2D echocardiograms and electrocardiograms were acquired from adult Xenopus laevis and X. tropicalis. Frogs were exposed to either isoflurane or tricaine to discern the effect of sedating agents on cardiac function. Cardiac dimensions, morphology, flow velocities, and electrophysiologic intervals were measured and evaluated by using bivariate and regression analyses. Normal cardiac dimensions relative to body weight and species were established by echocardiography. Normal conduction intervals were determined by electrocardiography and did not vary by body weight or species. Anesthetic agent did not affect ejection fraction or flow velocity but did alter the QRS duration and QT interval. Echocardiographic and electrocardiographic studies in Xenopus provide information about cardiac anatomy and physiology and can readily be used for longitudinal analyses of developmental inquiries. Body weight, species, and anesthetic agent are factors that should be considered in experimental design and analyses. PMID:20412684

Bartlett, Heather L; Escalera, Robert B; Patel, Sonali S; Wedemeyer, Elesa W; Volk, Kenneth A; Lohr, Jamie L; Reinking, Benjamin E

2010-01-01

118

Identification of sources of low frequency variability of arterial blood pressure: cardiac output acts as a buffer and not as a source  

PubMed Central

Arterial blood pressure (ABP) short term variability is due to beat-by-beat fluctuations in cardiac output (CO) and total peripheral resistance (TPR), which have distinct effects at low and high frequencies. In particular, it was shown that CO is able to buffer TPR slow oscillations in the LF band, but it has not been addressed if CO can contribute to oscillations of ABP in this band. In this paper, we propose a model for the identification of ABP variability sources, in order to show evidence that CO fluctuations are not a source of ABP LF oscillations, but they only buffer ABP variability of vasomotor origin. PMID:21097024

Aletti, Federico; Chen, Xiaoxiao; Sala-Mercado, Javier A.; Hammond, Robert L.; O’Leary, Donal S.; Cerutti, Sergio; Baselli, Giuseppe; Mukkamala, Ramakrishna

2014-01-01

119

STATISTICAL AND DYNAMICAL DOWNSCALING OF GLOBAL MODEL OUTPUT FOR U.S. NATIONAL ASSESSMENT HYDROLOGICAL ANALYSES  

Microsoft Academic Search

1. NTRODUCTION Analyses performed for the US National Assessment require accurate projections of climate at scales below those resolved by global General Circulation Models (GCMs). Two techniques have been developed that counter this deficiency: semi- empirical (statistical) downscaling (SDS) of GCM outputs, and regional climate models (RCMs) nested within a GCM. To date, few studies have compared SDS and RCM

W. J. Gutowski; R. Wilby; L. E. Hay; C. J. Anderson; R. W. Arritt; M. P. Clark; G. H. Leavesley; Z. Pan; R. Silva; E. S. Takle

120

Economic Input-Output Life Cycle Assessment of Water Reuse Strategies in Residential Buildings  

EPA Science Inventory

This paper evaluates the environmental sustainability and economic feasibility of four water reuse designs through economic input-output life cycle assessments (EIO-LCA) and benefit/cost analyses. The water reuse designs include: 1. Simple Greywater Reuse System for Landscape Ir...

121

Comparison of general circulation model outputs and ensemble assessment of climate change using a Bayesian approach  

NASA Astrophysics Data System (ADS)

A number of general circulation models (GCMs) have been developed to project future global climate change. Unfortunately, projected results are different and it is not known which set of GCM outputs are more creditable than the others. The objective of this work is to present a Bayesian approach to compare GCM outputs and make an ensemble assessment of climate change. This method is applied to Cannonsville Reservoir watershed, New York, USA. The GCM outputs under the 20C3M scenario for a historical time period of 1981-2000 are used to calculate posterior probabilities, and the outputs under the scenarios (A1B, A2 and B1) for the future time period of 2084-2100 are then processed using the Bayesian modeling averaging (BMA) which is a statistical procedure that infers a consensus prediction by weighing individual predictions based on the posterior probabilities, with the better performing predictions receiving higher weights. The obtained results reveal that the posterior probabilities are slightly different for four variables including average, maximum and minimum temperatures, and shortwave radiation, implying that the GCM outputs are qualitatively different for these four variables, but the distributions of posterior probabilities are flat for precipitation and wind speed, suggesting that the GCM outputs are qualitatively similar for these two variables. The results also show that no one set of GCM data are the best for all six meteorological variables. Furthermore, the results indicate that the projected changes are for regional warming, but the changes in precipitation, wind speed, and shortwave radiation depend on the emission scenarios and seasons. The application of the method demonstrates that the Bayesian approach is useful for the comparison of GCM outputs and making ensemble assessments of climate change.

Huang, Yongtai

2014-11-01

122

Serum uric acid is inversely proportional to estimated stroke volume and cardiac output in a large sample of pharmacologically untreated subjects: data from the Brisighella Heart Study.  

PubMed

Serum uric acid is representative for xanthine-oxidase, the key enzyme involved in the production of uric acid, which is up-regulated in the failing heart, and may play an important role in the pathophysiologic process that leads to heart failure. In our study, we investigated the relation between stroke volume, cardiac output and serum uric acid in a large sample of overall healthy pharmacologically untreated subjects. The Brisighella Heart Study included 2,939 men and women between the ages of 14-84 without prior coronary heart disease or cerebrovascular disease who were not taking antihypertensive therapy at baseline. For this study, we selected 734 adult subjects enrolled in the last Brisighella population survey not taking antihypertensive, antidiabetic, lipid-lowering and uric acid-lowering drugs, and who were also not affected by chronic heart failure or by gout. The main predictors of cardiac functionality parameters were mean arterial pressure (MAP), HR, SUA and age (all p < 0.001), while gender, BMI, LDL-cholesterol, HDL-cholesterol, triglycerides, fasting plasma glucose, creatinine, estimated glomerular filtration rate, physical activity and smoking habit were not significantly associated (all p > 0.05). In particular, there is a strong relation between estimated cardiac output and serum uric acid (B = -0.219, p < 0.001) and between stroke volume and serum uric acid (B = -3.684, p < 0.001). These observations might have an impact on future considerations about serum uric acid as an early inexpensive marker of heart function decline in the general population. PMID:24214336

Cicero, Arrigo Francesco Giuseppe; Rosticci, Martina; Parini, Angelo; Baronio, Cristina; D'Addato, Sergio; Borghi, Claudio

2014-09-01

123

MRI assessment of cardiac tumours: part 2, spectrum of appearances of histologically malignant lesions and tumour mimics  

PubMed Central

Cardiac magnetic resonance imaging (MRI) is the reference standard technique for assessment and characterization of a suspected cardiac tumour. It provides an unrestricted field of view, high temporal resolution and non-invasive tissue characterization based on multi-parametric assessment of the chemical micro-environment. Sarcomas account for around 95% of all primary malignant cardiac tumours with lymphoma, and primary pericardial mesothelioma making up most of the remainder of cases. By contrast cardiac metastases are much more common. In this article we review the MRI features of the spectrum of histologically malignant cardiac and pericardial tumours as well as some potential tumour mimics. PMID:25525582

Shahid, Muhammad; Ganeshan, Arul; Baijal, Shobhit; Simpson, Helen; Watkin, Richard W.

2014-01-01

124

Assessment of pain during rest and during activities in the postoperative period of cardiac surgery  

PubMed Central

Objective to assess the intensity and site of pain after Cardiac Surgery through sternotomy during rest and while performing five activities. Method descriptive study with a prospective cohort design. A total of 48 individuals participated in the study. A Multidimensional Scale for Pain Assessment was used. Results postoperative pain from cardiac surgery was moderate during rest and decreased over time. Pain was also moderate during activities performed on the 1st and 2nd postoperative days and decreased from the 3rd postoperative day, with the exception of coughing, which diminished only on the 6th postoperative day. Coughing, turning over, deep breathing and rest are presented in decreased order of intensity. The region of the sternum was the most frequently reported site of pain. Conclusion the assessment of pain in the individuals who underwent cardiac surgery during rest and during activities is extremely important to adapt management and avoid postoperative complications and delayed surgical recovery. PMID:24553714

de Mello, Larissa Coelho; Rosatti, Silvio Fernando Castro; Hortense, Priscilla

2014-01-01

125

A regional version of a US economic input-output life-cycle assessment model  

Microsoft Academic Search

Background, Aims and Scope  Life cycle assessment models typically use product-specific, plant-level or national aggregate data. However, many decisions\\u000a by regional policy makers would be better informed by local or regional aggregate data. This research is intended to construct\\u000a and apply a regional US economic input-output analysis-based life cycle assessment (REIO-LCA) model based upon publicly available\\u000a datasets. The model uses Gross

Gyorgyi Cicas; Chris T. Hendrickson; Arpad Horvath; H. Scott Matthews

2007-01-01

126

Non-invasive in vivo measurement of cardiac output in C57BL/6 mice using high frequency transthoracic ultrasound: evaluation of gender and body weight effects.  

PubMed

Even though mice are being increasingly used as models for human cardiovascular diseases, non-invasive monitoring of cardiovascular parameters such as cardiac output (CO) in this species is challenging. In most cases, the effects of gender and body weight (BW) on these parameters have not been studied. The objective of this study was to provide normal reference values for CO in C57BL/6 mice, and to describe possible gender and/or BW associated differences between them. We used 30-MHz transthoracic Doppler ultrasound to measure hemodynamic parameters in the ascending aorta [heart rate (HR), stroke volume (SV), stroke index (SI), CO, and cardiac index (CI)] in ten anesthetized mice of either sex. No differences were found for HR, SV, and CO. Both SI and CI were statistically lower in males. However, after normalization for BW, these differences disappeared. These results suggest that if comparisons of cardiovascular parameters are to be made between male and female mice, values should be standardized for BW. PMID:24852337

Domínguez, Elisabet; Ruberte, Jesús; Ríos, José; Novellas, Rosa; Del Alamo, Maria Montserrat Rivera; Navarro, Marc; Espada, Yvonne

2014-10-01

127

A Case of Femoral Arteriovenous Fistula Causing High-Output Cardiac Failure, Originally Misdiagnosed as Chronic Fatigue Syndrome  

PubMed Central

Percutaneous arterial catheterisation is commonly undertaken for a range of diagnostic and interventional procedures. Iatrogenic femoral arteriovenous fistulas are an uncommon complication of these procedures. Most are asymptomatic and close spontaneously, but can rarely increase in size leading to the development of symptoms. We report a case of an iatrogenic femoral arteriovenous fistula, causing worsening congestive cardiac failure, in a 34-year-old marathon runner. This was originally diagnosed as chronic fatigue syndrome. Following clinical examination, duplex ultrasound, and CT angiography a significant arteriovenous fistula was confirmed. Elective open surgery was performed, leading to a dramatic and rapid improvement in symptoms. Femoral arteriovenous fistulas have the potential to cause significant haemodynamic effects and can present many years after the initial procedure. Conservative, endovascular, and open surgical management strategies are available. PMID:24959370

Porter, J.; Al-Jarrah, Q.; Richardson, S.

2014-01-01

128

The feasibility and applications of non-invasive cardiac output monitoring, thromboelastography and transit-time flow measurement in living-related renal transplantation surgery: results of a prospective pilot observational study  

PubMed Central

Introduction Delayed graft function (DGF) remains a significant and detrimental postoperative phenomenon following living-related renal allograft transplantation, with a published incidence of up to 15%. Early therapeutic vasodilatory interventions have been shown to improve DGF, and modifications to immunosuppressive regimens may subsequently lessen its impact. This pilot study assesses the potential applicability of perioperative non-invasive cardiac output monitoring (NICOM), transit-time flow monitoring (TTFM) of the transplant renal artery and pre-/perioperative thromboelastography (TEG) in the early prediction of DGF and perioperative complications. Methods Ten consecutive living-related renal allograft recipients were studied. Non-invasive cardiac output monitoring commenced immediately following induction of anaesthesia and was maintained throughout the perioperative period. Doppler-based TTFM was performed during natural haemostatic pauses in the transplant surgery: immediately following graft reperfusion and following ureteric implantation. Central venous blood sampling for TEG was performed following induction of anaesthesia and during abdominal closure. Results A single incidence of DGF was seen within the studied cohort and one intra-operative (thrombotic) complication noted. NICOM confirmed a predictable trend of increased cardiac index (CI) following allograft reperfusion (mean CI - clamped: 3.17?±?0.29 L/min/m2, post-reperfusion: 3.50?±?0.35 L/min/m2; P?

2014-01-01

129

Assessment of the effect of ofatumumab on cardiac repolarization.  

PubMed

Ofatumumab is a human monoclonal antibody that binds to a unique CD20 epitope on the surface of B lymphocytes, resulting in efficient lysis of CD20-expressing cells via complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity. The potential effect of ofatumumab on cardiac repolarization and the relationship between ofatumumab concentration and change in corrected QT interval (?QTcF) were evaluated in data from three clinical trials in 82 patients with chronic lymphocytic leukemia receiving ofatumumab alone (n?=?14), ofatumumab with chemotherapy (n?=?33), and chemotherapy alone (n?=?35). Because of ofatumumab accumulation, baseline QTcF interval was recorded prior to the first infusion for each patient. No patient had a post-baseline QTcF interval >480 milliseconds or a ?QTcF >60 milliseconds; five patients (four on ofatumumab) had a ?QTcF between 30 and 60 milliseconds. At cycle 6 (week 21; 308??g/mL), there was an increase in QTcF in patients on ofatumumab treatment, with an estimated between-treatment difference (90% CI) of 12.5 (4.5, 20.5) milliseconds. However, at the visit with the highest median concentration (week 8; 1386??g/mL), median ?QTcF was 4.8 milliseconds. There was no significant relationship between ofatumumab plasma concentration and ?QTcF. Ofatumumab did not have a clinically significant effect on cardiac repolarization. PMID:25103870

Jewell, Roxanne C; Laubscher, Kevin; Lewis, Eric; Fang, Lei; Gafoor, Zarina; Carey, Jodi; McKeown, Astrid; West, Sarah; Wright, Oliver; Sedoti, Donna; Dixon, Iestyn; Hottenstein, Charles Scott; Chan, Geoffrey

2015-01-01

130

Noninvasive Cardiac Flow Assessment Using High Speed Magnetic Resonance Fluid Motion Tracking  

PubMed Central

Cardiovascular diseases can be diagnosed by assessing abnormal flow behavior in the heart. We introduce, for the first time, a magnetic resonance imaging-based diagnostic that produces sectional flow maps of cardiac chambers, and presents cardiac analysis based on the flow information. Using steady-state free precession magnetic resonance images of blood, we demonstrate intensity contrast between asynchronous and synchronous proton spins. Turbulent blood flow in cardiac chambers contains asynchronous blood proton spins whose concentration affects the signal intensities that are registered onto the magnetic resonance images. Application of intensity flow tracking based on their non-uniform signal concentrations provides a flow field map of the blood motion. We verify this theory in a patient with an atrial septal defect whose chamber blood flow vortices vary in speed of rotation before and after septal occlusion. Based on the measurement of cardiac flow vorticity in our implementation, we establish a relationship between atrial vorticity and septal defect. The developed system has the potential to be used as a prognostic and investigative tool for assessment of cardiac abnormalities, and can be exploited in parallel to examining myocardial defects using steady-state free precession magnetic resonance images of the heart. PMID:19479033

Wong, Kelvin Kian Loong; Kelso, Richard Malcolm; Worthley, Stephen Grant; Sanders, Prashanthan; Mazumdar, Jagannath; Abbott, Derek

2009-01-01

131

A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 1: Methodology (7 pp)  

Microsoft Academic Search

Goal, Scope and Background. Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an

Yurika Nishioka; Jonathan I. Levy; Gregory A. Norris; Deborah H. Bennett; John D. Spengler

2005-01-01

132

Assessment of cardiac functions in fetuses of gestational diabetic mothers.  

PubMed

We investigated cardiac function in 67 fetuses of gestational diabetic mothers (FGDMs) and 122 fetuses of healthy mothers between 24 and 36 weeks of gestation. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. Fetal echocardiograms were performed at 24, 28, 32, and 36 weeks of gestation. Glycated hemoglobin (HbA1c) levels were obtained from all pregnant women at 24 weeks of gestation. The mean age of diabetic pregnant women was significantly greater than that of controls. Serum HbA1c values of both groups were within normal limits, but they were significantly greater in the diabetic group (p = 0.003). The increase in peak aortic and pulmonary artery velocities were greater in FGDM (p < 0.001). No pathological interventricular septal (IVS) hypertrophy was observed. There was a significant increase in IVS thickness in FGDM compared with controls, which was more prominent at the end of the third trimester (p < 0.001). During the course of pregnancy, mitral E-wave (p < 0.001), A-wave (p = 0.007), tricuspid E-wave (p < 0.001) and A-wave (p = 0.002) velocities were greater in FGDM. The increases in mitral E/A and tricuspid E/A ratios were lower in FGDM with advancing gestation. The E a-wave (p = 0.02), A a-wave (p = 0.04), and S a-wave (p < 0.001) velocities of the right-ventricular (RV) free wall and the E a (p = 0.02) and A a (p = 0.01) velocities of the left-ventricle (LV) posterior wall were greater in FGDM during the course of pregnancy. The E a/A a ratio of the RV posterior wall was greater in FGDM with advancing gestation (p < 0.03). LV and RV E/E a ratios were similar in both groups. The LV myocardial performance index measured by pulsed-wave Doppler was greater in FGDM (p < 0.001). We detected diastolic dysfunction in FGDM. The data suggest that gestational diabetes mellitus may impair ventricular diastolic functions without causing pathological fetal myocardial hypertrophy. We detected subclinical diastolic dysfunction using both pulsed-wave and tissue Doppler imaging in FGDM. PMID:23780554

Balli, Sevket; Pac, Feyza Aysenur; Ece, ?brahim; Oflaz, Mehmet Burhan; Kibar, Ayse Esin; Kandemir, Ömer

2014-01-01

133

Effects of active chronic cocaine use on cardiac sympathetic neuronal function assessed by carbon-11-hydroxyephedrine  

SciTech Connect

Cardiac toxicity of cocaine has been linked to its inhibitory effect on norepinephrine reuptake by sympathetic nerve terminals of the heart. Carbon-11-hydroxyephedrine is a positron-emitting tracer that has been validated as a highly specific marker for norepinephrine transporter activity of the sympathetic nerve terminals and thus makes possible in vivo assessment of the effect of cocaine on norepinephrine reuptake and storage in the cardiac sympathetic nerve terminals. The aim of the study was to use the catecholamine analog {sup 11}C-hydroxyephedrine with PET to determine whether active chronic use of cocaine in women modifies the function of sympathetic nerve terminals of the heart. Six normal female volunteers and nine female active chronic cocaine users were studied. Cardiac regional {sup 11}C-hydroxyephedrine uptake and blood flow, as assessed with {sup 13}N-ammonia, were determined using semi-quantitative polar map analysis of myocardial tracer distribution. Carbon-11-hydroxyephedrine cardiac retention was quantified using dynamic data acquisition and kinetic analysis of blood and tissue activity. 27 refs., 4 figs., 3 tabs.

Melon, P.G.; Boyd, C.J.; McVey, S. [Univ. of Michigan Medical Center, Ann Arbor, MI (United States)]|[Univ. of Michigan, Ann Arbor, MI (United States)] [and others

1997-03-01

134

Bayesian Spatial-temporal Model for Cardiac Congenital Anomalies and Ambient Air Pollution Risk Assessment  

PubMed Central

We introduce a Bayesian spatial-temporal hierarchical multivariate probit regression model that identifies weeks during the first trimester of pregnancy which are impactful in terms of cardiac congenital anomaly development. The model is able to consider multiple pollutants and a multivariate cardiac anomaly grouping outcome jointly while allowing the critical windows to vary in a continuous manner across time and space. We utilize a dataset of numerical chemical model output which contains information regarding multiple species of PM2.5. Our introduction of an innovative spatial-temporal semiparametric prior distribution for the pollution risk effects allows for greater flexibility to identify critical weeks during pregnancy which are missed when more standard models are applied. The multivariate kernel stick-breaking prior is extended to include space and time simultaneously in both the locations and the masses in order to accommodate complex data settings. Simulation study results suggest that our prior distribution has the flexibility to outperform competitor models in a number of data settings. When applied to the geo-coded Texas birth data, weeks 3, 7 and 8 of the pregnancy are identified as being impactful in terms of cardiac defect development for multiple pollutants across the spatial domain. PMID:23482298

Warren, Joshua; Fuentes, Montserrat; Herring, Amy; Langlois, Peter

2013-01-01

135

Evaluation of optical imaging and spectroscopy approaches for cardiac tissue depth assessment  

SciTech Connect

NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo results provided reasonable fit to the experimental data.

Lin, B; Matthews, D; Chernomordik, V; Gandjbakhche, A; Lane, S; Demos, S G

2008-02-13

136

Noninvasive Physiologic Assessment of Coronary Stenoses Using Cardiac CT  

PubMed Central

Coronary CT angiography (CCTA) has become an important noninvasive imaging modality in the diagnosis of coronary artery disease (CAD). CCTA enables accurate evaluation of coronary artery stenosis. However, CCTA provides limited information on the physiological significance of stenotic lesions. A noninvasive “one-stop-shop” diagnostic test that can provide both anatomical significance and functional significance of stenotic lesions would be beneficial in the diagnosis and management of CAD. Recently, with the introduction of novel techniques, such as myocardial CT perfusion, CT-derived fractional flow reserve (FFRCT), and transluminal attenuation gradient (TAG), CCTA has emerged as a noninvasive method for the assessment of both anatomy of coronary lesions and its physiological consequences during a single study. This review provides an overview of the current status of new CT techniques for the physiologic assessments of CAD.

Fan, Zhanming

2015-01-01

137

Functional Cardiac Magnetic Resonance Imaging (MRI) in the Assessment of Myocardial Viability and Perfusion  

PubMed Central

Executive Summary Objective The objective of this health technology policy assessment was to determine the effectiveness safety and cost-effectiveness of using functional cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability and perfusion in patients with coronary artery disease and left ventricular dysfunction. Results Functional MRI has become increasingly investigated as a noninvasive method for assessing myocardial viability and perfusion. Most patients in the published literature have mild to moderate impaired LV function. It is possible that the severity of LV dysfunction may be an important factor that can alter the diagnostic accuracy of imaging techniques. There is some evidence of comparable or better performance of functional cardiac MRI for the assessment of myocardial viability and perfusion compared with other imaging techniques. However limitations to most of the studies included: Functional cardiac MRI studies that assess myocardial viability and perfusion have had small sample sizes. Some studies assessed myocardial viability/perfusion in patients who had already undergone revascularization, or excluded patients with a prior MI (Schwitter et al., 2001). Lack of explicit detail of patient recruitment. Patients with LVEF >35%. Interstudy variability in post MI imaging time(including acute or chronic MI), when patients with a prior MI were included. Poor interobserver agreement (kappa statistic) in the interpretation of the results. Traditionally, 0.80 is considered “good”. Cardiac MRI measurement of myocardial perfusion to as an adjunct tool to help diagnose CAD (prior to a definitive coronary angiography) has also been examined in some studies, with methodological limitations, yielding comparable results. Many studies examining myocardial viability and perfusion report on the accuracy of imaging methods with limited data on long-term patient outcome and management. Kim et al. (2000) revealed that the transmural extent of hyperenhancement was significantly related to the likelihood of improvement in contractility after revascularization. However, the LVEF in the patient population was 43% prior to revascularization. It is important to know whether the technique has the same degree of accuracy in patients who have more severe LV dysfunction and who would most benefit from an assessment of myocardial viability. “Substantial” viability used as a measure of a patient’s ability to recover after revascularization has not been definitively reported (how much viability is enough?). Patients with severe LV dysfunction are more likely to have mixtures of surviving myocardium, including normal, infarcted, stunned and hibernating myocardium (Cowley et al., 1999). This may lead to a lack of homogeneity of response to testing and to revascularization and contribute to inter- and intra-study differences. There is a need for a large prospective study with adequate follow-up time for patients with CAD and LV dysfunction (LVEF<35%) comparing MRI and an alternate imaging technique. There is some evidence that MRI has comparable sensitivity, specificity and accuracy to PET for determining myocardial viability. However, there is a lack of evidence comparing the accuracy of these two techniques to predict LV function recovery. In addition, some studies refer to PET as the gold standard for the assessment of myocardial viability. Therefore, PET may be an ideal noninvasive imaging comparator to MRI for a prospective study with follow-up. To date, there is a lack of cost-effectiveness analyses (or any economic analyses) of functional cardiac MRI versus an alternate noninvasive imaging method for the assessment of myocardial viability/perfusion. Conclusion There is some evidence that the accuracy of functional cardiac MRI compares favourably with alternate imaging techniques for the assessment of myocardial viability and perfusion. There is insufficient evidence whether functional cardiac MRI can better select which patients [who have CAD and severe LV dysfuncti

2003-01-01

138

Heart mass and the maximum cardiac output of birds and mammals: implications for estimating the maximum aerobic power input of flying animals  

PubMed Central

Empirical studies of cardiovascular variables suggest that relative heart muscle mass (relative Mh) is a good indicator of the degree of adaptive specialization for prolonged locomotor activities, for both birds and mammals. Reasonable predictions for the maximum oxygen consumption of birds during flight can be obtained by assuming that avian heart muscle has the same maximum physiological and biomechanical performance as that of terrestrial mammals. Thus, data on Mh can be used to provide quantitative estimates for the maximum aerobic power input (aerobic Pi,max) available to animals during intense levels of locomotor activity. The maximum cardiac output of birds and mammals is calculated to scale with respect to Mh (g) as 213 Mh0.88+-0.04 (ml min-1), while aerobic Pi,max is estimated to scale approximately as 11 Mh0.88+-0.09 (W). In general, estimated inter-species aerobic Pi,max, based on Mh for all bird species (excluding hummingbirds), is calculated to scale with respect to body mass (Mb in kg) as 81 Mb0.82+-0.11 (W). Comparison of family means for Mh indicate that there is considerable diversity in aerobic capacity among birds and mammals, for example, among the medium to large species of birds the Tinamidae have the smallest relative Mh (0.25 per cent) while the Otidae have unusually large relative Mh (1.6 per cent). Hummingbirds have extremely large relative Mh (2.28 per cent), but exhibit significant sexual dimorphism in their scaling of Mh and flight muscle mass, so that when considering hummingbird flight performance it may be useful to control for sexual differences in morphology. The estimated scaling of aerobic Pi,max (based on Mh and Mb in g) for male and female hummingbirds is 0.51 Mb0.83 +/-0.07 and 0.44 Mb0.85+- 0.11 (W), respectively. Locomotory muscles are dynamic structures and it might be anticipated that where additional energetic 'costs' occur seasonally (e.g. due to migratory fattening or the development of large secondary sexual characteristics) then the relevant cardiac and locomotor musculature might also be regulated seasonally. This is an important consideration, both due to the intrinsic interest of studying muscular adaptation to changes in energy demand, but also as a confounding variable in the practical use of heart rate to estimate the energetics of animals. Haemoglobin concentration (or haematocrit) may also be a confounding variable. Thus, it is concluded that data on the cardiovascular and flight muscle morphology of animals provides essential information regarding the behavioural, ecological and physiological significance of the flight performance of animals.

Bishop, C. M.

1997-01-01

139

MRI assessment of cardiac tumours: part 1, multiparametric imaging protocols and spectrum of appearances of histologically benign lesions  

PubMed Central

Cardiac magnetic resonance imaging (MRI) is the reference standard technique for assessment and characterization of a suspected cardiac tumour. It provides an unrestricted field of view, high temporal resolution and non-invasive tissue characterization based on multi-parametric assessment of the chemical micro-environment. MRI exploits differences in hydrogen proton density in conjunction with T1 and T2 relaxation properties of different tissues to help differentiation normal from abnormal and benign from malignant lesions. In this article we review specific cardiac MRI techniques, tumour protocol design and the appearance of the spectrum of histologically benign tumours. PMID:25525581

Shahid, Muhammad; Ganeshan, Arul; Baijal, Shobhit; Simpson, Helen; Watkin, Richard W.

2014-01-01

140

Economic input-output life-cycle assessment of trade between Canada and the United States.  

PubMed

With increasing trade liberalization, attempts at accounting for environmental impacts and energy use across the manufacturing supply chain are complicated by the predominance of internationally supplied resources and products. This is particularly true for Canada and the United States, the world's largest trading partners. We use an economic input-output life-cycle assessment (EIO-LCA) technique to estimate the economy-wide energy intensity and greenhouse gas (GHG) emissions intensity for 45 manufacturing and resource sectors in Canada and the United States. Overall, we find that U.S. manufacturing and resource industries are about 1.15 times as energy-intensive and 1.3 times as GHG-intensive as Canadian industries, with significant sector-specific discrepancies in energy and GHG intensity. This trend is mainly due to a greater direct reliance on fossil fuels for many U.S. industries, in addition to a highly fossil-fuel based electricity mix in the U.S. To account for these differences, we develop a 76 sector binational EIO-LCA model that implicitly considers trade in goods between Canada and the U.S. Our findings show that accounting for trade can significantly alter the results of life-cycle assessment studies, particularly for many Canadian manufacturing sectors, and the production/consumption of goods in one country often exerts significant energy- and GHG-influences on the other. PMID:17396636

Norman, Jonathan; Charpentier, Alex D; MacLean, Heather L

2007-03-01

141

Computerized assessment of motion-contaminated calcified plaques in cardiac multidetector CT  

SciTech Connect

An automated method for evaluating the image quality of calcified plaques with respect to motion artifacts in noncontrast-enhanced cardiac computed tomography (CT) images is introduced. This method involves using linear regression (LR) and artificial neural network (ANN) regression models for predicting two patient-specific, region-of-interest-specific, reconstruction-specific and temporal phase-specific image quality indices. The first is a plaque motion index, which is derived from the actual trajectory of the calcified plaque and is represented on a continuous scale. The second is an assessability index, which reflects the degree to which a calcified plaque is affected by motion artifacts, and is represented on an ordinal five-point scale. Two sets of assessability indices were provided independently by two radiologists experienced in evaluating cardiac CT images. Inputs for the regression models were selected from 12 features characterizing the dynamic, morphological, and intensity-based properties of the calcified plaques. Whereas LR-velocity (LR-V) used only a single feature (three-dimensional velocity), the LR-multiple (LR-M) and ANN regression models used the same subset of these 12 features selected through stepwise regression. The regression models were parameterized and evaluated using a database of simulated calcified plaque images from the dynamic NCAT phantom involving nine heart rate/multi-sector gating combinations and 40 cardiac phases covering two cardiac cycles. Six calcified plaques were used for the plaque motion indices and three calcified plaques were used for both sets of assessability indices. In one configuration, images from the second cardiac cycle were used for feature selection and regression model parameterization, whereas images from the first cardiac cycle were used for testing. With this configuration, repeated measures concordance correlation coefficients (CCCs) and associated 95% confidence intervals for the LR-V, LR-M, and ANN were 0.817 [0.785, 0.848], 0.894 [0.869, 0.916], and 0.917 [0.892, 0.936] for the plaque motion indices. For the two sets of assessability indices, CCC values for the ANN model were 0.843 [0.791, 0.877] and 0.793 [0.747, 0.828]. These two CCC values were statistically greater than the CCC value of 0.689 [0.648, 0.727], which was obtained by comparing the two sets of assessability indices with each other. These preliminary results suggest that the variabilities of assessability indices provided by regression models can lie within the variabilities of the indices assigned by independent observers. Thus, the potential exists for using regression models and assessability indices for determining optimal phases for cardiac CT image interpretation.

King, Martin; Giger, Maryellen L.; Suzuki, Kenji; Bardo, Dianna M. E.; Greenberg, Brent; Lan Li; Pan Xiaochuan [Department of Radiology, Committee on Medical Physics, University of Chicago, Chicago, Illinois 60637 (United States)

2007-12-15

142

Pulmonary hypertension in systemic sclerosis determines cardiac autonomic dysfunction assessed by heart rate turbulence.  

PubMed

There is limited data on heart rate turbulence (HRT) in systemic sclerosis (SSc) patients, potentially threatened with cardiac autonomic dysfunction. We performed 24-hour Holter monitoring for HRT assessment in 45 patients with SSc and 30 healthy controls. Abnormal HRT defined as turbulence onset (TO) >or=0.0% and/or turbulence slope (TS)assessment indicates a frequent impairment of cardiac autonomic nervous system in SSc patients. Moreover, older age in these patients and especially PH are independent significant predictors of cardiac autonomic dysfunction. PMID:19101049

Bienias, Piotr; Ciurzy?ski, Micha?; Korczak, Dariusz; Jankowski, Krzysztof; Gli?ska-Wielochowska, Maria; Liszewska-Pfejfer, Danuta; Gli?ski, Wies?aw; Pruszczyk, Piotr

2010-06-11

143

Mastering temporary invasive cardiac pacing.  

PubMed

Competent management of patients with an invasive temporary pacemaker is an important skill for nurses who provide care for critically ill patients with cardiac disease. Such management requires familiarity with normal cardiovascular anatomy and physiology, conduction system defects, and rhythm interpretation. With an understanding of the basic concepts of rate, output, chambers, sensitivity, and capture, pacing can be done with ease. Care of patients with a temporary invasive pacemaker requires monitoring cardiac tissue and hemodynamic status, observing for changes that would indicate the need for modifications in the pacemaker settings. Nursing interventions include physical assessment, care of the insertion site, routine threshold testing, and management of the pulse generator. PMID:15206293

Overbay, Devorah; Criddle, Laura

2004-06-01

144

[Pain assessment and training: the impact on pain control after cardiac surgery].  

PubMed

We analyzed the effects of training and the application of a form for the systematized assessment of pain control after cardiac surgery on pain intensity and supplementary use of morphine. Three patient groups underwent a non-randomized clinical trial with standardized analgesic prescription. In Group I, the nursing staff did not receive specific training regarding the assessment and management of pain, and patients were treated following the established protocol of the institution. In Groups II and III, the nursing staff received targeted training. In Group II the nursing staff used a form for the systematized assessment of pain, which was not used in Group III. Group II presented a lower intensity of pain and greater consumption of supplementary morphine compared to Groups I and II. Training associated with the systematized assessment form increased the chance of identifying pain and influenced nurses' decision-making process, thus promoting pain relief among patients. PMID:23515807

Silva, Magda Aparecida Dos Santos; Pimenta, Cibele Andrucioli de Mattos; Cruz, Diná de Almeida Lopes Monteiro da

2013-02-01

145

Post-Traumatic Stress Disorder among Cardiac Patients: Prevalence, Risk Factors, and Considerations for Assessment and Treatment.  

PubMed

There is increasing awareness of the impact of post-traumatic stress disorder (PTSD) on physical health, particularly cardiovascular disease. We review the literature on the role of trauma in the development of cardiovascular risk factors and disease, aftermath of a cardiac event, and risk for recurrence in cardiac patients. We explore possible mechanisms to explain these relationships, as well as appropriate assessment and treatment strategies for this population. Our main conclusion is that screening and referral for appropriate treatments are important given the high prevalence rates of PTSD in cardiac populations and the associated impact on morbidity and mortality. PMID:25545708

Tulloch, Heather; Greenman, Paul S; Tassé, Vanessa

2014-01-01

146

Wearable seismocardiography for the beat-to-beat assessment of cardiac intervals during sleep.  

PubMed

Seismocardiogram (SCG) can be detected during sleep by a textile-based wearable system. This pilot study preliminarily explores the feasibility of a beat-to-beat estimation of cardiac mechanical features (RR interval, RRI, Pre-Ejection Period, PEP, Isovolumic Contraction Time, ICT, Left Ventricular Ejection Time, LVET, Isovolumic Relaxation Time, IRT) from the joint ECG and SCG assessment during sleep. The analysis of two 30-min sleep data segments from one healthy subject, indicated that 1) respiration largely influence the dynamics of most of the parameters; 2) variability of cardiac intervals is only marginally influenced by the RRI variability; 3) appreciable spectral power at frequencies <;0.1 is only observed in the RRI spectrum and not in the spectra of the other indexes; 4) IRT has a broadband variability, that is clearly different from the dynamics of the other indexes. These findings represent the very first description of the beat-to-beat variability of cardiac mechanical indexes. Further investigations on a larger population are in progress to confirm the present results. PMID:25571386

Di Rienzo, Marco; Vaini, Emanuele; Castiglioni, Paolo; Lombardi, Prospero; Parati, Gianfranco; Lombardi, Carolina; Meriggi, Paolo; Rizzo, Francesco

2014-08-01

147

A novel approach for assessing cardiac fibrosis using label-free second harmonic generation.  

PubMed

To determine whether second harmonic generation (SHG) can be used as a novel and improved label-free technique for detection of collagen deposition in the heart. To verify whether SHG will allow accurate quantification of altered collagen deposition in diseased hearts following hypertrophic remodelling. Minimally invasive transverse aortic banding (MTAB) of mouse hearts was used to generate a reproducible model of cardiac hypertrophy. Physiological and functional assessment of hypertrophic development was performed using echocardiography and post-mortem analysis of remodelled hearts. Cardiac fibroblasts were isolated from sham-operated and hypertrophied hearts and proliferation rates compared. Multi-photon laser scanning microscopy was used to capture both two-photon excited autofluorescence (TPEF) and SHG images simultaneously in two channels. TPEF images were subtracted from SHG images and the resulting signal intensities from ventricular tissue sections were calculated. Traditional picrosirius red staining was used to verify the suitability of the SHG application. MTAB surgery induced significant hypertrophic remodelling and increased cardiac fibroblast proliferation. A significant increase in the density of collagen fibres between hypertrophic and control tissues (p < 0.05) was evident using SHG. Similar increases and patterns of staining were observed using parallel traditional picrosirius red staining of collagen. Label-free SHG microscopy provides a new alternative method for quantifying collagen deposition in fibrotic hearts. PMID:23921804

Martin, Tamara P; Norris, Greg; McConnell, Gail; Currie, Susan

2013-12-01

148

Comparison of simultaneous and sequential SPECT imaging for discrimination tasks in assessment of cardiac defects  

NASA Astrophysics Data System (ADS)

Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two radionuclide signals. We consider a simultaneous rest 99mTc-sestamibi/123I-BMIPP imaging protocol in place of the commonly used sequential rest/stress 99mTc-sestamibi protocol. The theoretical precision with which the severity of a cardiac defect and the transmural extent of infarct can be measured is computed for simultaneous and sequential SPECT imaging, and their performance is compared for discriminating (1) degrees of defect severity and (2) sub-endocardial from transmural defects. We consider cardiac infarcts for which reduced perfusion and metabolism are observed. From an information perspective, simultaneous imaging is found to yield comparable or improved performance compared with sequential imaging for discriminating both severity of defect and transmural extent of infarct, for three defects of differing location and size.

Trott, C. M.; Ouyang, J.; El Fakhri, G.

2010-11-01

149

Spatial downscaling of global climate model output for site-specific assessment of crop production and soil erosion  

Microsoft Academic Search

Spatial and temporal mismatches between coarse resolution projections of global climate models (GCMs) and fine resolution data requirements of ecosystems models are the major obstacles for assessing the site-specific climatic impacts of climate change on natural resources and ecosystems. The objectives of this study were to: (i) develop a simple method for statistically downscaling GCM monthly output at the native

X.-C. Zhang

2005-01-01

150

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings  

Microsoft Academic Search

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification\\u000a of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT),\\u000a the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study\\u000a was to evaluate the accuracy of DSCT in the

S. Busch; T. R. C. Johnson; B. J. Wintersperger; N. Minaifar; A. Bhargava; C. Rist; M. F. Reiser; C. Becker; K. Nikolaou

2008-01-01

151

Effects of levosimendan/furosemide infusion on Plasma Brain Natriuretic Peptide, echocardiographic parameters and cardiac output in end-stage heart failure patients  

PubMed Central

Summary Background Acute decompensation heart failure (ADHF) remains a cause of hospitalization in patients with end-stage congestive HF. The administration of levosimendan in comparison with a standard therapy in CHF patients admitted for ADHF was analysed. Material/Methods Consecutive patients admitted for ADHF (NYHA class III–IV) were treated with levosimendan infusion 0.1 ?g/kg/min or with furosemide infusion 100–160 mg per day for 48 hours (control group). All subjects underwent determination of brain natriuretic peptide (BNP), non-invasive cardiac output (CO), and echocardiogram at baseline, at the end of therapy and 1 week after therapy. Results Seven patients admitted for 20 treatments in 16 months (age 66 years; mean admission/year 5.4) were treated with levosimendan and compared with 7 patients admitted for 15 treatments (age 69.1 years; mean admission/year 6.1). At the end of levosimendan therapy, BNP decreased (from 679.7±512.1 pg/ml to 554.2±407.6 pg/ml p=0.03), and 6MWT and LVEF improved (from 217.6±97.7 m to 372.2±90.4 m p=0.0001; from 22.8±9.1% to 25.4±9.8% p=0.05). Deceleration time, E/A, E/E’, TAPSE, pulmonary pressure and CO did not change significantly after levosimendan therapy and after 1 week. At follow-up, only 6-min WT and NYHA class showed a significant improvement (p=0.0001, p=0.001 respectively). The furosemide infusion reduced NYHA class and body weight (from 3.4±0.6 to 2.3±0.5 p=0.001; from 77.5±8.6 kg to 76±6.6 kg p=0.04), but impaired renal function (clearances from 56.3±21.9 ml/min to 41.2±10.1 ml/min p=0.04). Conclusions Treating end-stage CHF patients with levosimendan improved BNP and LVEF, but this effect disappeared after 1 week. The amelioration of 6MWT and NYHA class lasted longer after levosimendan infusion. PMID:21358614

Feola, Mauro; Lombardo, Enrico; Taglieri, Camillo; Vallauri, Paola; Piccolo, Salvatore; Valle, Roberto

2011-01-01

152

[Assessment of the prognosis in patients who remain comatose after resuscitation from cardiac arrest.  

PubMed

In Denmark there are around 3,500 unexpected cardiac arrests (CA) out of hospital each year. There is an unknown number of CA in hospitals. The survival rate after CA outside a hospital in Denmark is 10% after 30 days. There are varying data for the neurological outcome in this group of patients. The purpose of this work is to disseminate new knowledge and to help standardizing the treatment in the group of patients who remain comatose after being resuscitated from CA. Assessment of the prognosis for a patient in this group can be made after 72 hours and a multi-modal approach to the patient is required. PMID:25294674

Ramberg, Emilie; Fedder, Anette Marianne; Dyrskog, Stig Eric; Degn, Niels Sanderhoff; Hassager, Christian; Jensen, Reinhold; Kirkegaard, Hans; Weber, Sven; Hoffmann-Petersen, Joachim Torp; Larsen, Niels Heden; Strange, Ditte Gry; Sonne, Morten; Lippert, Freddy K

2014-06-30

153

Developing a genetic fuzzy system for risk assessment of mortality after cardiac surgery.  

PubMed

Cardiac events could be taken into account as the leading causes of death throughout the globe. Such events also trigger an undesirable increase in what treatment procedures cost. Despite the giant leaps in technological development in heart surgery, coronary surgery still carries the high risk of the mortality. Besides, there is still a long way ahead to accurately predict and assess the mortality risk. This study is an attempt to develop an expert system for the risk assessment of mortality following the cardiac surgery. The developed system involves three main steps. In the first step, a filtering feature selection method is applied to select the best features. In the second step, an ad hoc data-driven method is utilized to generate the preliminary fuzzy inference system. Finally, a hybrid optimization method is presented to select the optimum subset of the rules. The study relies on 1,811 samples to evaluate the diagnosis performance of the proposed system. The obtained classification accuracy is very promising with regard to other benchmark classification methods including binary logistic regression (LR) and multilayer perceptron neural network (MLP) with the same attributes. The developed system leads to 100% sensitivity and 84.7% specificity, while LR and MLP methods statistically come up with lower figures (65, 78.6 and 65%, 75.8%), respectively. Now, a fuzzy supportive tool can be potentially taken as an alternative for the current mortality risk assessment system that are applied in coronary surgeries, and are chiefly based on crisp database. PMID:25119238

Nouei, Mahyar Taghizadeh; Kamyad, Ali Vahidian; Sarzaeem, MahmoodReza; Ghazalbash, Somayeh

2014-10-01

154

Time-varying stroke volume using sonomicrometry with direct cardiac compression (DCC)  

Microsoft Academic Search

Implantable direct cardiac compression (DCC) systems such as our Heart Patch Pump can assist the failing heart without the risk of blood contact. To provide realtime, accurate support of pumping function, these devices need to assess hemodynamic variables such as cardiac output. For the Heart Patch Pump, we have based our control algorithm on time-varying stroke volume (SV(t)) estimates using

A. A. Martinez-Coll; H. T. Nguyen; R. Zielinski; Y. F. Huang; S. Plekhanov; S. N. Hunyor

2002-01-01

155

Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer  

PubMed Central

Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods:Whitaker ’s study [“Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,” Opt. Express 16(11), 8150–8173 (2008)]10.1364/OE.16.008150 on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by localization receiver operating characteristic (LROC) [P. Khurd and G. Gindi, “Decision strategies maximizing the area under the LROC curve,” Proc. SPIE 5749, 150–161 (2005)]10.1117/12.595915 or estimation receiver operating characteristic (EROC) [E. Clarkson, “Estimation receiver operating characteristic curve and ideal observers for combined detection/estimation tasks,” J. Opt. Soc. Am. A 24, B91–B98 (2007)]10.1364/JOSAA.24.000B91 curves. Results: The area under the LROC/EROC curve (AULC/AUEC) and the true positive fraction (TPF) at a specific false positive fraction (FPF) can be treated as the figures of merit. For radii estimation with a 1 mm tolerance, the AUEC values of the GE27, GE19, and GE13 systems are 0.8545, 0.8488, and 0.8329, and the TPF at FPF = 5% are 77.1%, 76.46%, and 73.55%, respectively. The assessment of all three systems revealed that the GE19 system yields estimated information and cardiac defect detectability very close to those of the GE27 system while using eight fewer detectors. Thus, 30% of the expensive detector units can be removed with confidence. Conclusions: As the results show, a combination of the SLO and LROC/EROC curves can determine the configuration that yields the most relevant estimation/detection information. Thus, this is a useful method for assessing cardiac SPECT systems. PMID:23298097

Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

2013-01-01

156

Interstitial Myocardial Fibrosis Assessed as Extracellular Volume Fraction with Low-Radiation-Dose Cardiac CT  

PubMed Central

Purpose: To develop a cardiac computed tomographic (CT) method with which to determine extracellular volume (ECV) fraction, with cardiac magnetic resonance (MR) imaging as the reference standard. Materials and Methods: Study participants provided written informed consent to participate in this institutional review board–approved study. ECV was measured in healthy subjects and patients with heart failure by using cardiac CT and cardiac MR imaging. Paired Student t test, linear regression analysis, and Pearson correlation analysis were used to determine the relationship between cardiac CT and MR imaging ECV values and clinical parameters. Results: Twenty-four subjects were studied. There was good correlation between myocardial ECV measured at cardiac MR imaging and that measured at cardiac CT (r = 0.82, P < .001). As expected, ECV was higher in patients with heart failure than in healthy control subjects for both cardiac CT and cardiac MR imaging (P = .03, respectively). For both cardiac MR imaging and cardiac CT, ECV was positively associated with end diastolic and end systolic volume and inversely related to ejection fraction (P < .05 for all). Mean radiation dose was 1.98 mSv ± 0.16 (standard deviation) for each cardiac CT acquisition. Conclusion: ECV at cardiac CT and that at cardiac MR imaging showed good correlation, suggesting the potential for myocardial tissue characterization with cardiac CT. © RSNA, 2012 PMID:22771879

Nacif, Marcelo Souto; Kawel, Nadine; Lee, Jason J.; Chen, Xinjian; Yao, Jianhua; Zavodni, Anna; Sibley, Christopher T.; Lima, João A. C.; Liu, Songtao

2012-01-01

157

The assessment of complexity in congenital cardiac surgery based on objective data.  

PubMed

When designed in 2000, the Aristotle Complexity Score was entirely based on subjective probability. This approach, based on the opinion of experts, was considered a good solution due to the limited amount of data available. In 2008, the next generation of the complexity score will be based on observed data available from over 100,000 congenital cardiac operations currently gathered in the congenital cardiac surgery databases of the Society of Thoracic Surgeons and the European Association for Cardio-Thoracic Surgery. A mortality score is created based on 70,000 surgeries harvested in the congenital databases of The Society of Thoracic Surgeons and The European Association for Cardio-Thoracic Surgery. It is derived from 118 congenital cardiovascular operations, representing 91% of the operations and including 97% of the patients. This Mortality Index of the new Aristotle Complexity Score could further be stratified into 5 levels with minimal within-group variation and maximal between-group variation, and may contribute to the planned unification of the Aristotle Complexity Score with the Risk Adjustment for Congenital Heart Surgery system. Similarly, a score quantifying morbidity risk is created. Due to the progress of congenital cardiac surgery, the mortality is today reduced to an average of 4%. No instrument currently exists to measure the quality of care delivered to the survivors representing 96% of the patients. An objective assessment of morbidity was needed. The Morbidity Index, based on 50,000 operations gathered in the congenital databases of The Society of Thoracic Surgeons and The European Association for Cardio-Thoracic Surgery, is derived from 117 congenital cardiovascular operations representing 90% of the operations and including 95% of the patients. This morbidity indicator is calculated on an algorithm based on length of stay in the hospital and time on the ventilator. The mortality and morbidity indicators will be part of the next generation of the complexity score, which will be named the Aristotle Average Complexity Score. It will be based on the sum of mortality, morbidity, and subjective technical difficulty. The introduction of objective data in assessment of mortality and morbidity in congenital cardiac surgery is a significant step forward, which should allow a better evaluation of the complexity of the operations performed by a given centre or surgeon. PMID:19063788

Clarke, David R; Lacour-Gayet, Francois; Jacobs, Jeffrey Phillip; Jacobs, Marshall L; Maruszewski, Bohdan; Pizarro, Christian; Edwards, Fred H; Mavroudis, Constantine

2008-12-01

158

Pulse Oximetry Wave Variation as a Noninvasive Tool to Assess Volume Status in Cardiac Surgery  

PubMed Central

OBJECTIVE: To compare variations of plethysmographic wave amplitude (?Ppleth) and to determine the percent difference between inspiratory and expiratory pulse pressure (?Pp) cutoff values for volume responsiveness in a homogenous population of postoperative cardiac surgery patients. INTRODUCTION: Intra-thoracic pressure variations interfere with stroke volume variation. Pulse pressure variations through arterial lines during mechanical ventilation have been recommended for the estimation of fluid responsiveness. Pulse oximetry may offer a non-invasive plethysmographic method to evaluate pulse pressure; this may be useful for guiding fluid replacement. METHODS: Controlled, prospective study in cardiac surgery patients under controlled ventilation. Simultaneous digital recordings of arterial pressure and plethysmographic waves were performed. ?Pp, systolic pressure (?Ps), ?Ppleth, and systolic component (?Spleth) were calculated. A ?Pp ? 13% identified fluid-responsive patients. Volume expansion was performed in responsive subjects. Systolic and amplitude components of pressure and plethysmographic waves were compared. RESULTS: In 50 measurements from 43 patients, ?Pp was correlated with (Ppleth (r=0.90, p<0.001), (Ps (r=0.90, p<0.001), and (Spleth (r=0.73, p<0.001). An aArea under ROC curve (AUC) identified the fluid responsiveness thresholds: (Ppleth of 11% (AUC = 0.95±0.04), (Ps of 8% (AUC=0.93±0.05), and (Spleth of 32% (AUC=0.82±0.07). A (Ppleth value ? 11% predicted (Pp ? 13% with 100% specificity and 91% sensitivity. Volume expansion, performed in 20 patients, changed (Pp, (Ppleth, (Ps and (Spleth significantly (p<0.008). CONCLUSIONS: ?Ppleth is well correlated with ?Pp and constitutes a simple and non-invasive method for assessing fluid responsiveness in patients following cardiac surgery. PMID:19488592

Westphal, Glauco A; Silva, Eliezer; Gonçalves, Anderson Roman; Filho, Milton Caldeira; Poli-de-Figueiredo, Luíz F

2009-01-01

159

Cardiac index assessment using bioreactance in patients undergoing cytoreductive surgery in ovarian carcinoma.  

PubMed

This clinical study compared the cardiac index (CI) assessed by the totally non-invasive method of bioreactance (CIBR) (NICOM™, Cheetah Medical, Vancouver, USA) to transpulmonary thermodilution (CITD) during cytoreductive surgery in ovarian carcinoma. The hypothesis was that CI could be assessed by bioreactance in an accurate and precise manner including accurate trending ability when compared to transpulmonary thermodilution. In 15 patients CIBR and CITD were assessed after induction of anesthesia, after opening of the peritoneum, hourly during the operative procedure, and 30 min after extubation. Trending ability was assessed between the described timepoints. In total 84 points of measurement were analyzed. Concordance correlation coefficient for repeated measures correlating the CIBR and CITD was 0.32. Bias was 0.26 l/min/m(2) (limits of agreement -1.39 and 1.92 l/min/m(2)). The percentage error was 50.7 %. Trending ability quantified by the mean of angles ? which are made by the ?CI vector and the line of identity (y = x) showed a value for CIBR of ? = 23.4°. CI assessment by bioreactance showed acceptable accuracy and trending ability. However, its precision was poor. Therefore, CI measurement can not be solely based on bioreactance in patients undergoing cytoreductive surgery in ovarian carcinoma. PMID:23689837

Kober, David; Trepte, Constantin; Petzoldt, Martin; Nitzschke, Rainer; Herich, Lena; Reuter, Daniel A; Haas, Sebastian

2013-12-01

160

Cardiac gated ventilation  

NASA Astrophysics Data System (ADS)

There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

Hanson, C. William, III; Hoffman, Eric A.

1995-05-01

161

Cardiac gated ventilation  

SciTech Connect

There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

Hanson, C.W. III [Hospital of the Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. Anesthesia; Hoffman, E.A. [Univ. of Iowa College of Medicine, Iowa City, IA (United States). Div. of Physiologic Imaging

1995-12-31

162

ICT Expenditures and Education Outputs/Outcomes in Selected Developed Countries: An Assessment of Relative Efficiency  

ERIC Educational Resources Information Center

Purpose: The aim of the paper is to review some previous researches examining ICT efficiency and the impact of ICT on educational output/outcome as well as different conceptual and methodological issues related to performance measurement. Design/methodology/approach: This paper adopts a non-parametric methodology, i.e. data envelopment analysis…

Aristovnik, Aleksander

2013-01-01

163

Resource and Output Equity as a Mechanism for Assessing Educational Opportunity in Korean Middle School Education  

ERIC Educational Resources Information Center

Korea is recognized as a high-performing country in international achievement studies; however, many researchers in and outside Korea have been worried about the existing gaps between high-socioeconomic and low-socioeconomic (SES) students in both student achievement and educational resources. We analyzed the resource and output equity of Korean…

Houck, Eric A.; Eom, Moonyoung

2012-01-01

164

Cardiac assessment of limb-girdle muscular dystrophy 2I patients: an echography, Holter ECG and magnetic resonance imaging study.  

PubMed

Mutations in the FKRP gene may be associated with cardiac involvement. The aim of our study was to assess myocardial involvement in patients with LGMD2I, using physical examination, echocardiography, resting and 24-h ambulatory electrocardiogram and cardiac magnetic resonance imaging, with particular attention to the detection of myocardial morphologic abnormalities. Patients were compared to matched controls. Twenty-three patients were enrolled (men 10--women 13; 32.3+/-9.5 years). Twenty-two had the C826A gene mutation (homozygous 12, heterozygous 10). Nine patients had severe muscle alterations, 10 had milder muscle involvement and 4 had isolated exertional myoglobinuria. When compared to controls, LGMD2I patients had reduced left ventricular ejection fraction (50.8+/-13.9 versus 66.6+/-3.8%, p<0.0001). Sixty percent of patients had reduced left ventricular ejection fraction, including 8% with severe reduced left ventricular ejection fraction <30%. None had significant arrhythmia. Gene mutation and the severity of the muscle disease were not predictive of cardiac involvement. Cardiac magnetic resonance imaging displayed a high prevalence of myocardial functional abnormalities, fatty replacement and fibrosis, among the 13 patients investigated. Reduced contractility and cardiac magnetic resonance imaging morphological abnormalities are highly prevalent in LGMD2I patients suggesting that all patients should be referred for cardiac evaluation. PMID:18639457

Wahbi, Karim; Meune, Christophe; Hamouda, El Hadi; Stojkovic, Tania; Laforêt, Pascal; Bécane, Henri Marc; Eymard, Bruno; Duboc, Denis

2008-08-01

165

A history of the role of the hERG channel in cardiac risk assessment.  

PubMed

The human ether-a-go-go-related gene (hERG, Kv11.1) K(+) channel plays an important role in cardiac repolarization. Following its cloning and expression it was established that inhibition of this channel was the molecular mechanism for many non-antiarrhythmic drugs that produce torsades de pointes associated with QT prolongation. Therefore the study of in vitro drug-hERG interactions has become an important part of modern safety pharmacology. Manual and automated patch clamp electrophysiology, in silico modeling, and hERG trafficking assays have been developed to aid in this study. The correlation between in vitro hERG IC50, drug exposure, QT prolongation in the thorough QT clinical trial and risk of TdP has greatly reduced drug withdrawals due to TdP. However a significant association with Type 1 errors in particular remains and may have a negative impact on drug development. Combining hERG data with other non-clinical and clinical markers of proarrhythmia will increase the specificity and sensitivity of cardiac risk assessment. hERG will continue to play an important role in drug development and safety pharmacology in the future. PMID:23538024

Rampe, David; Brown, Arthur M

2013-01-01

166

What is the utility of preoperative frailty assessment for risk stratification in cardiac surgery?  

PubMed

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether frailty scoring can be used either separately or combined with conventional risk scores to predict survival and complications. Five hundred and thirty-five papers were found using the reported search, of which nine cohort studies represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There is a paucity of evidence, as advanced age is a criterion for exclusion in most randomized controlled trials. Conventional models of risk following cardiac surgery are not calibrated to accurately predict the outcomes in the elderly and do not currently include frailty parameters. There is no universally accepted definition for frailty, but it is described as a physiological decline in multiple organ systems, decreasing a patient's capacity to withstand the stresses of surgery and disease. Frailty is manifest clinically as deficits in functional capacity, such as slow ambulation and impairments in the activities of daily living (ADL). Analysis of predictive models using area under receiver operating curves (AUC) suggested only a modest benefit by adding gait speed to a Society of Thoracic Surgeons (STS score)-Predicted Risk of Mortality or Major Morbidity (PROM) risk score (AUC 0.04 mean difference). However, a specialist frailty assessment tool named FORECAST was found to be superior at predicting adverse outcomes at 1 year compared with either EuroSCORE or STS score (AUC 0.09 mean difference). However, risk models incorporating frailty parameters require further validation and have not been widely adopted. Routine collection of objective frailty measures such as 5-metre walk time and ADL assessment will help to provide data to develop new risk-assessment models to facilitate risk stratification and clinical decision-making in elderly patients. Based on the best evidence currently available, we conclude that frailty is an independent predictor of adverse outcome following cardiac surgery or transcatheter aortic valve implantation, increasing the risk of mortality 2- to 4-fold compared with non-frail patients. PMID:23667068

Bagnall, Nigel Mark; Faiz, Omar; Darzi, Ara; Athanasiou, Thanos

2013-08-01

167

What is the utility of preoperative frailty assessment for risk stratification in cardiac surgery?  

PubMed Central

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether frailty scoring can be used either separately or combined with conventional risk scores to predict survival and complications. Five hundred and thirty-five papers were found using the reported search, of which nine cohort studies represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There is a paucity of evidence, as advanced age is a criterion for exclusion in most randomized controlled trials. Conventional models of risk following cardiac surgery are not calibrated to accurately predict the outcomes in the elderly and do not currently include frailty parameters. There is no universally accepted definition for frailty, but it is described as a physiological decline in multiple organ systems, decreasing a patient's capacity to withstand the stresses of surgery and disease. Frailty is manifest clinically as deficits in functional capacity, such as slow ambulation and impairments in the activities of daily living (ADL). Analysis of predictive models using area under receiver operating curves (AUC) suggested only a modest benefit by adding gait speed to a Society of Thoracic Surgeons (STS score)-Predicted Risk of Mortality or Major Morbidity (PROM) risk score (AUC 0.04 mean difference). However, a specialist frailty assessment tool named FORECAST was found to be superior at predicting adverse outcomes at 1 year compared with either EuroSCORE or STS score (AUC 0.09 mean difference). However, risk models incorporating frailty parameters require further validation and have not been widely adopted. Routine collection of objective frailty measures such as 5-metre walk time and ADL assessment will help to provide data to develop new risk-assessment models to facilitate risk stratification and clinical decision-making in elderly patients. Based on the best evidence currently available, we conclude that frailty is an independent predictor of adverse outcome following cardiac surgery or transcatheter aortic valve implantation, increasing the risk of mortality 2- to 4-fold compared with non-frail patients. PMID:23667068

Bagnall, Nigel Mark; Faiz, Omar; Darzi, Ara; Athanasiou, Thanos

2013-01-01

168

Assessment of cardiac and pulmonary function in children with juvenile idiopathic arthritis.  

PubMed

Juvenile idiopathic arthritis (JIA) is the most common rheumatologic disorder of childhood. It is a group of diseases characterized by chronic synovitis and associated with many extra-articular manifestations including cardiac and pulmonary involvement. Cardiac involvement as pericarditis, myocarditis and valvular disease is common in JIA. There are, however, few descriptions concerning systolic and diastolic functions of the left ventricle (LV) and the development of lung disease in children with JIA. The study was carried out to detect the cardiac and pulmonary involvement and to study the systolic and diastolic function of the left ventricle in a group of children with juvenile idiopathic arthritis. Forty-five children with JIA without any cardiac or pulmonary symptoms and 30 age- and sex-matched controls were included in the study. M-mode, two-dimensional and pulsed Doppler echocardiography (ECHO) was performed on 36 patients. Tissue Doppler ECHO examination was performed on 24 patients to assess systolic and diastolic functions of left ventricle. Pulmonary function tests: Forced vital capacity (FVC%), the predicted forced expiratory volume in the first second (FEV(1)%) and FEV(1)/FVC ratio and peak expiratory flow (PEF), total lung capacity (TLC) and residual volume (RV), carbon monoxide diffusing capacity of the lung (DLCO) and DLCO/alveolar volume (VA) were evaluated in 32 patients. Informed consent was obtained from all children's parents. The study protocol was approved by ethical committee of Faculty of Medicine, Assiut University. In this study, children with JIA had higher systolic and diastolic blood pressures, resting heart rate, left ventricle systolic size and volume (4.35 ± 0.68 vs. 3.92 ± 0.28, P value = 0.02). On Doppler and tissue Doppler analysis, the JIA group had lower peak early filling velocity (E, m/s), higher peak atrial filling velocity (A, m/s) and prolonged diastolic E and A waves deceleration times and isovolumic relaxation time (IRT) compared to control. Regarding pulmonary function tests, children with JIA showed significant decrease in FVC, PEF, Pimax, Pemax and DLCO compared to normal controls. This decrease was not related to age, height or weight of these patients. There was significant inverse correlation between lung function parameters and the rheumatoid factor titer, erythrosedimentation rate, disease duration and the duration of methotrexate use (P < 0.01). Despite of an asymptomatic cardiopulmonary status, significant systolic and diastolic functional abnormalities exist in children with JIA. Also, both restrictive and obstructive lung impairments were found. PMID:20658239

Alkady, Eman A M; Helmy, Hatem A R; Mohamed-Hussein, Aliaë A R

2012-01-01

169

Statistical Downscaling and Bias Correction of Climate Model Outputs for Climate Change Impact Assessment in the U.S. Northeast  

NASA Technical Reports Server (NTRS)

Statistical downscaling can be used to efficiently downscale a large number of General Circulation Model (GCM) outputs to a fine temporal and spatial scale. To facilitate regional impact assessments, this study statistically downscales (to 1/8deg spatial resolution) and corrects the bias of daily maximum and minimum temperature and daily precipitation data from six GCMs and four Regional Climate Models (RCMs) for the northeast United States (US) using the Statistical Downscaling and Bias Correction (SDBC) approach. Based on these downscaled data from multiple models, five extreme indices were analyzed for the future climate to quantify future changes of climate extremes. For a subset of models and indices, results based on raw and bias corrected model outputs for the present-day climate were compared with observations, which demonstrated that bias correction is important not only for GCM outputs, but also for RCM outputs. For future climate, bias correction led to a higher level of agreements among the models in predicting the magnitude and capturing the spatial pattern of the extreme climate indices. We found that the incorporation of dynamical downscaling as an intermediate step does not lead to considerable differences in the results of statistical downscaling for the study domain.

Ahmed, Kazi Farzan; Wang, Guiling; Silander, John; Wilson, Adam M.; Allen, Jenica M.; Horton, Radley; Anyah, Richard

2013-01-01

170

3D left ventricular extracellular volume fraction by low-radiation dose cardiac CT: Assessment of interstitial myocardial fibrosis  

PubMed Central

Background Myocardial fibrosis leads to impaired cardiac function and events. Extracellular volume fraction (ECV) assessed with an iodinated contrast agent and measured by cardiac CT may be a useful noninvasive marker of fibrosis. Objective The purpose of this study was to develop and evaluate a 3-dimensional (3D) ECV calculation toolkit (ECVTK) for ECV determination by cardiac CT. Methods Twenty-four subjects (10 systolic heart failure, age, 60 ± 17 years; 5 diastolic failure, age 56 ± 20 years; 9 matched healthy subjects, age 59 ± 7 years) were evaluated. Cardiac CT examinations were done on a 320-multidetector CT scanner before and after 130 mL of iopamidol (Isovue-370; Bracco Diagnostics, Plainsboro, NJ, USA) was administered. A calcium score type sequence was performed before and 7 minutes after contrast with single gantry rotation during 1 breath hold and single cardiac phase acquisition. ECV was calculated as (?HUmyocardium/?HUblood) × (1 ? Hct) where Hct is the hematocrit, and ?HU is the change in Hounsfield unit attenuation = HUafter iodine ? HUbefore iodine. Cardiac magnetic resonance imaging was performed to assess myocardial structure and function. Results Mean 3D ECV values were significantly higher in the subjects with systolic heart failure than in healthy subjects and subjects with diastolic heart failure (mean, 41% ± 6%, 33% ± 2%, and 35% ± 5%, respectively; P = 0.02). Interobserver and intraobserver agreements were excellent for myocardial, blood pool, and ECV (intraclass correlation coefficient, >0.90 for all). Higher 3D ECV by cardiac CT was associated with reduced systolic circumferential strain, greater end-diastolic and -systolic volumes, and lower ejection fraction (r = 0.70, r = 0.60, r = 0.73, and r = ?0.68, respectively; all P < 0.001). Conclusion 3D ECV by cardiac CT can be performed with ECVTK. We demonstrated increased ECV in subjects with systolic heart failure compared with healthy subjects. Cardiac CT results also showed good correlation with important functional heart biomarkers, suggesting the potential for myocardial tissue characterization with the use of 3D ECV by cardiac CT. This trial is registered at www.ClinicalTrials.gov as NCT01160471. PMID:23333188

Nacif, Marcelo Souto; Liu, Yixun; Yao, Jianhua; Liu, Songtao; Sibley, Christopher T.; Summers, Ronald M.; Bluemke, David A.

2014-01-01

171

Optical assessment of the cardiac rhythm of contracting cardiomyocytes in vitro and a pulsating heart in vivo for pharmacological screening  

PubMed Central

Our quest in the pathogenesis and therapies targeting human heart diseases requires assessment of the contractile dynamics of cardiac models of varied complexity, such as isolated cardiomyocytes and the heart of a model animal. It is hence beneficial to have an integral means that can interrogate both cardiomyocytes in vitro and a heart in vivo. Herein we report an application of dual-beam optical reflectometry to determine noninvasively the rhythm of two representative cardiac models–chick embryonic cardiomyocytes and the heart of zebrafish. We probed self-beating cardiomyocytes and revealed the temporally varying contractile frequency with a short-time Fourier transform. Our unique dual-beam setup uniquely records the atrial and ventricular pulsations of zebrafish simultaneously. To minimize the cross talk between signals associated with atrial and ventricular chambers, we particularly modulated the two probe beams at distinct frequencies and extracted the signals specific to individual cardiac chambers with phase-sensitive detection. With this setup, we determined the atrio-ventricular interval, a parameter that is manifested by the electrical conduction from the atrium to the ventricle. To demonstrate pharmacological applications, we characterized zebrafish treated with various cardioactive and cardiotoxic drugs, and identified abnormal cardiac rhythms and atrioventricular (AV) blocks of varied degree. In light of its potential capability to assess cardiac models both in vitro and in vivo and to screen drugs with cardioactivity or toxicity, we expect this approach to have broad applications ranging from cardiopharmacology to developmental biology. PMID:24877019

Lai, Yu-Cheng; Chang, Wei-Tien; Lin, Kuen-You; Liau, Ian

2014-01-01

172

MIQuant – Semi-Automation of Infarct Size Assessment in Models of Cardiac Ischemic Injury  

PubMed Central

Background The cardiac regenerative potential of newly developed therapies is traditionally evaluated in rodent models of surgically induced myocardial ischemia. A generally accepted key parameter for determining the success of the applied therapy is the infarct size. Although regarded as a gold standard method for infarct size estimation in heart ischemia, histological planimetry is time-consuming and highly variable amongst studies. The purpose of this work is to contribute towards the standardization and simplification of infarct size assessment by providing free access to a novel semi-automated software tool. The acronym MIQuant was attributed to this application. Methodology/Principal Findings Mice were subject to permanent coronary artery ligation and the size of chronic infarcts was estimated by area and midline-length methods using manual planimetry and with MIQuant. Repeatability and reproducibility of MIQuant scores were verified. The validation showed high correlation (rmidline length?=?0.981; rarea?=?0.970 ) and agreement (Bland-Altman analysis), free from bias for midline length and negligible bias of 1.21% to 3.72% for area quantification. Further analysis demonstrated that MIQuant reduced by 4.5-fold the time spent on the analysis and, importantly, MIQuant effectiveness is independent of user proficiency. The results indicate that MIQuant can be regarded as a better alternative to manual measurement. Conclusions We conclude that MIQuant is a reliable and an easy-to-use software for infarct size quantification. The widespread use of MIQuant will contribute towards the standardization of infarct size assessment across studies and, therefore, to the systematization of the evaluation of cardiac regenerative potential of emerging therapies. PMID:21980376

Esteves, Tiago; de Pina, Maria de Fátima; Guedes, Joana G.; Freire, Ana; Quelhas, Pedro; Pinto-do-Ó, Perpétua

2011-01-01

173

Assessment of catchment scale connectivity in different catchments using measured suspended sediment output  

NASA Astrophysics Data System (ADS)

Recent developments in hydrology and geomorphology include the connectivity principle, which describes how different elements in a landscape are connected and how water and matter moves between these elements. So far, studies on connectivity have been mainly of a conceptual nature and have been done on a small scale, while studies that map, quantitatively establish relations, and model water and sediment transport in connectivity are rare. In this study we established a relation between change in connectivity within four catchments and the time of year by using suspended sediment data. The data were collected for four catchments in Navarra, Spain of which two catchments are dominated by forest and pasture, while the other two catchments are dominated by agriculture and have no forest. Data were collected during a 13 year period; 4 samples were taken a day at 6 hour intervals which were mixed to obtain a daily average suspended sediment concentration. This was then converted into daily suspended sediment output using the measured total daily discharge. The effect of precipitation on the sediment output data was minimized by using an antecedent precipitation index (API), which consists of the precipitation of the current day added by the precipitation of the previous 14 days, where the influence of the previous days decays exponentially with time. The daily total suspended sediment output was divided by the API, to obtain a measure for sediment output independent of precipitation. This sediment output then serves as a measure for the connectivity within the catchment. The connectivity of the four catchments throughout the years will be compared to each other and we hypothesise that the two catchments dominated by forests and pastures will change only slightly throughout the year, whereas we expect to see large differences in connectivity in the two agricultural catchments. The agricultural catchments are likely to display a highly varying connectivity throughout the seasons due to changes in vegetation cover of the fields throughout the year, whereas daily variations will likely be small due to a slowly changing connectivity.

Masselink, Rens; Keesstra, Saskia; Seeger, Manuel

2014-05-01

174

Magnetic Resonance Imaging Assessment of Regional Cerebral Blood Flow after Asphyxial Cardiac Arrest in Immature Rats  

PubMed Central

Cerebral blood flow (CBF) alterations after asphyxial cardiac arrest (CA) are not defined in developmental animal models or humans. We characterized regional and temporal changes in CBF from 5 to 150 min after asphyxial CA of increasing duration (8.5, 9, 12 min) in postnatal day (PND) 17 rats using the noninvasive method of arterial spin-labeled magnetic resonance imaging (ASL-MRI). We also assessed blood brain barrier (BBB) permeability, and evaluated the relationship between CBF and mean arterial pressure after resuscitation. After all durations of asphyxia CBF alterations were region-dependent. After 8.5 and 9 min asphyxia, intense subcortical hyperemia at 5 min was followed by return of CBF to baseline values by 10 minutes. After 12 min asphyxia, hyperemia was absent and hypoperfusion reached a nadir of 38-65% of baselines with the lowest values in the cortex. BBB was impermeable to gadoteridol 150 min after CA. CBF in the 12 min CA group was blood pressure passive at 60 min assessed via infusion of epinephrine. ASL-MRI assessment of CBF after asphyxial CA in PND 17 rats reveals marked duration and region-specific reperfusion patterns and identifies possible new therapeutic targets. PMID:18827831

Manole, Mioara D.; Foley, Lesley M.; Hitchens, T. Kevin; Kochanek, Patrick M.; Hickey, Robert W.; Bayir, Hülya; Alexander, Henry; Ho, Chien; Clark, Robert S.B.

2008-01-01

175

Rapid pediatric cardiac assessment of flow and ventricular volume with compressed sensing parallel imaging volumetric cine phase-contrast MRI  

PubMed Central

Purpose Quantification of cardiac flow and ventricular volumes comprise essential goals of many congenital heart MRI examinations, often requiring acquisition of multiple two-dimensional phase contrast (2DPC) and bright blood cine SSFP planes. Scan prescription however, is lengthy and highly reliant on an imager well-versed in structural heart disease. Though also lengthy, 3D time-resolved phase-contrast (4DPC) MRI yields global flow patterns and is simpler to prescribe. We therefore sought to accelerate 4DPC and determine whether equivalent flow and volume measurements could be extracted. Materials and Methods 4DPC was modified for higher acceleration with compressed-sensing. Custom software was developed to process 4DPC images. With IRB-approval and HIPAA-compliance, we studied 29 patients referred for congenital cardiac MRI, who underwent a routine clinical protocol including cine short-axis stack SSFP and 2DPC, followed by contrast-enhanced 4DPC. To compare quantitative measurements, Bland-Altman analysis, paired t-tests, and F-tests were used. Results Ventricular end-diastolic, end-systolic and stroke volumes obtained from 4DPC and SSFP were well-correlated (?=0.91–0.95, r2=0.83–0.90), with no statistically significant difference. Ejection fractions were well-correlated in a subpopulation that underwent higher-resolution compressed-sensing 4DPC (?=0.88, r2=0.77). 4DPC and 2DPC flow rates were also well-correlated (?=0.90, r2=0.82). Excluding ventricles with valvular insufficiency, cardiac outputs derived from outlet valve flow and stroke volumes were more consistent by 4DPC than by 2DPC and SSFP. Conclusion Combined parallel imaging and compressed sensing can be applied to 4DPC. With custom software, flow and ventricular volumes may be extracted with comparable accuracy to SSFP and 2DPC. Further, cardiac outputs were more consistent by 4DPC. PMID:22358022

Hsiao, Albert; Lustig, Michael; Alley, Marcus T.; Murphy, Mark; Chan, Frandics P.; Herfkens, Robert J.; Vasanawala, Shreyas S.

2012-01-01

176

Lower limb alactic anaerobic power output assessed with different techniques in morbid obesity.  

PubMed

Short-term alactic anaerobic performance in jumping (5 consecutive jumps with maximal effort), sprint running (8 m) and stair climbing (modified Margaria test) were measured in 75 obese subjects (BMI: 40.3+/-5.0 kg/m2) and in 36 lean control subjects (BMI: 22.4+/-3.2 kg/m2) of the same age and gender distribution. The results show that obese subjects attained a significantly lower specific (per unit body mass) power output both in jumping (W(spec,j); p<0.001) and stair climbing (W(spec,s); p<0.001) and run at a significantly lower average velocity (v; p<0.001) during sprinting. In spite of the different motor skillfulness required to accomplish the jumping and climbing tests, W(spec,s) (and hence the vertical velocity in climbing, v(v)) was closely correlated with W(spec,j) (R2=0.427, p<0.001). In jumping, although the average force during the positive work phase was significantly higher in obese subjects (p<0.001), no difference between the 2 groups was detected in absolute power. In stair climbing the absolute power output of obese resulted significantly higher (18%) than that of lean controls (p<0.001). In sprint running, the lower average horizontal velocity attained by obese subjects also entailed a different locomotion pattern with shorter step length (L(s); p<0.001), lower frequency (p<0.001) and longer foot contact time with ground (T(c,r); p<0.001). W(spec,j) seems to be a determinant of the poorer motor performance of obese, being significantly correlated with: I) the vertical displacement of the centre of gravity (R2=0.853, p<0.001) in jumping; II) with v(v) in stair climbing; and III) with T(c,r) (R2=0.492, p<0.001), L(s) (R2=0.266, p<0.001) and v (R2=0.454, p<0.001) in sprinting. The results suggest that obese individuals, although partially hampered in kinetic movements, largely rely on their effective specific power output to perform complex anaerobic tasks, and they suffer from the disproportionate excess of inert mass of fat. Furthermore, in view of the sedentary style of life and the consequent degree of muscle de-conditioning accompanying this condition, it may prove useful to implement rehabilitation programs for obesity with effective power training protocols. PMID:11929084

Lafortuna, C L; Fumagalli, E; Vangeli, V; Sartorio, A

2002-02-01

177

Tests of muscle power output assess rapid movement performance when normalized for body size.  

PubMed

Among other routinely tested physical abilities, the tests of rapid movement performance and the tests of direct assessment of muscle power have been independently evaluated in complex batteries of physical fitness tests. Based on the scaling effects, we hypothesized that the tests of rapid movement performance assess the same physical ability as the tests of direct assessment of muscle power properly normalized for the effect of body size. Young physically active men (n = 111) were evaluated on 23 physical ability tests based on the assessment of muscle strength, muscle power, and rapid movement performance. When non-normalized data were used, a principle component analysis revealed a structure with overlapping tests from the above-mentioned groups including the indices of body size. However, when the indices of muscle strength and directly assessed muscle power were properly normalized for the effect of body size, the obtained structure was in line with the hypothesis. Most of the tests of both the direct assessment of muscle power and rapid movement performance proved to belong to the same factor, whereas the muscle strength tests and body size measures, respectively, loaded the remaining 2 factors. This result suggests that the rapid movement performance could be employed to assess muscle power and, possibly, the neuromuscular efficiency in general, which could be important for understanding some basic aspects of the design and function of the human locomotor system. An important practical implication of our findings could be that the direct assessment of muscle power (that usually requires expensive equipment and complex data processing procedures) could be skipped from the complex batteries of physical fitness tests and replaced by generally simpler tests of rapid movement performance. PMID:19620902

Nedeljkovic, Aleksandar; Mirkov, Dragan M; Markovic, Srdjan; Jaric, Slobodan

2009-08-01

178

Multiple-output support vector machine regression with feature selection for arousal/valence space emotion assessment.  

PubMed

Human emotion recognition (HER) allows the assessment of an affective state of a subject. Until recently, such emotional states were described in terms of discrete emotions, like happiness or contempt. In order to cover a high range of emotions, researchers in the field have introduced different dimensional spaces for emotion description that allow the characterization of affective states in terms of several variables or dimensions that measure distinct aspects of the emotion. One of the most common of such dimensional spaces is the bidimensional Arousal/Valence space. To the best of our knowledge, all HER systems so far have modelled independently, the dimensions in these dimensional spaces. In this paper, we study the effect of modelling the output dimensions simultaneously and show experimentally the advantages in modeling them in this way. We consider a multimodal approach by including features from the Electroencephalogram and a few physiological signals. For modelling the multiple outputs, we employ a multiple output regressor based on support vector machines. We also include an stage of feature selection that is developed within an embedded approach known as Recursive Feature Elimination (RFE), proposed initially for SVM. The results show that several features can be eliminated using the multiple output support vector regressor with RFE without affecting the performance of the regressor. From the analysis of the features selected in smaller subsets via RFE, it can be observed that the signals that are more informative into the arousal and valence space discrimination are the EEG, Electrooculogram/Electromiogram (EOG/EMG) and the Galvanic Skin Response (GSR). PMID:25570122

Torres-Valencia, Cristian A; Alvarez, Mauricio A; Orozco-Gutierrez, Alvaro A

2014-08-01

179

Cardiac risk in the treatment of breast cancer: assessment and management  

PubMed Central

As the number of long-term breast cancer survivors has increased, the side effects of adjuvant cancer therapy, such as cardiac toxicity, remain clinically important. Although the cardiac toxicity due to anthracyclines, radiotherapy, or trastuzumab is well-documented, several issues need to be clarified and are the subjects of extensive ongoing clinical research. This review summarizes the incidence of cardiac toxicity due to breast cancer adjuvant therapy and highlights the current trends in early detection and management of cardiac toxicities. PMID:25653554

Valachis, Antonis; Nilsson, Cecilia

2015-01-01

180

Contractile reserve assessed by dobutamine test identifies super-responders to cardiac resynchronization therapy  

PubMed Central

Introduction In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker. Material and methods The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (?WMSI) and ?LVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation. Results A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ?WMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ?EF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ?WMSI ? 0.7 and ? 14% for ?EF are the best discriminators for a super-response. Patients with ?WMSI ? 0.7 and ?EF ? 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up. Conclusions Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT. PMID:25276151

Milasinovic, Goran; Angelkov, Lazar; Ristic, Velibor; Tomovic, Milosav; Jurcevic, Ruzica; Otasevic, Petar

2014-01-01

181

Global assessment of agreement among streamflow projections using CMIP5 model outputs  

NASA Astrophysics Data System (ADS)

Runoff outputs from 11 atmosphere-ocean general circulation models (AOGCMs) participating in the fifth phase of Coupled Model Intercomparison Project were used to evaluate the changes in streamflow and agreement among AOGCMs at the end of 21st century. Under the highest emission scenario (Representative Concentration Pathways (RCP) 8.5), high flow is projected to increase in northern high latitudes of Eurasia and North America, Asia, and eastern Africa, while mean and low flows are both projected to decrease in Europe, Middle East, southwestern United States, and Central America. Projected changes under RCP4.5 show similar spatial distribution but with lower magnitude. The model spread of projected changes, however, is found to be large under both scenarios. Bootstrapped Mann-Whitney-Wilcoxon U test revealed that projected changes of streamflow regimes are statistically not significant in 8-32% (19-59%) of the world under RCP8.5 (RCP4.5). The model agreement on projected increase or decrease in mean and high flows is stronger under RCP8.5 than that under RCP4.5. On the other hand, the projected changes in low flow are robust in both scenarios with strong model agreement. In ˜7% (4%) of the world, high flow is projected to increase and low flow is projected to decrease, whereas in ˜29% (13%) all mean, high, and low flows are projected to increase under RCP8.5 (RCP4.5).

Koirala, Sujan; Hirabayashi, Yukiko; Mahendran, Roobavannan; Kanae, Shinjiro

2014-05-01

182

Accounting for the biogeochemical cycle of nitrogen in input-output life cycle assessment.  

PubMed

Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen cycle. This paper incorporates the biogeochemical cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen cycle. This paper emphasizes the need for methods to manage the N cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online. PMID:23869533

Singh, Shweta; Bakshi, Bhavik R

2013-08-20

183

Wearable seismocardiography: towards a beat-by-beat assessment of cardiac mechanics in ambulant subjects.  

PubMed

Seismocardiogram (SCG) is the measure of the micro-vibrations produced by the heart contraction and blood ejection into the vascular tree. Over time, a large body of evidence has been collected on the ability of SCG to reflect cardiac mechanical events such as opening and closure of mitral and aortic valves, atrial filling and point of maximal aortic blood ejection. We recently developed a smart garment, named MagIC-SCG, that allows the monitoring of SCG, electrocardiogram (ECG) and respiration out of the laboratory setting in ambulant subjects. The present pilot study illustrates the results of two different experiments performed to obtain a first evaluation on whether a dynamical assessment of indexes of cardiac mechanics can be obtained from SCG recordings obtained by MagIC-SCG. In the first experiment, we evaluated the consistency of the estimates of two indexes of cardiac contractility, the pre-ejection period, PEP, and the left ventricular ejection time, LVET. This was done in the lab, by reproducing an experimental protocol well known in literature, so that our measures derived from SCG could have been compared with PEP and LVET reference values obtained by traditional techniques. Six healthy subjects worn MagIC-SCG while assuming two different postures (supine and standing); PEP was estimated as the time interval between the Q wave in ECG and the SCG wave corresponding to the opening of aortic valve; LVET was the time interval between the SCG waves corresponding to the opening and closure of the aortic valve. The shift from supine to standing posture produced a significant increase in PEP and PEP/LVET ratio, a reduction in LVET and a concomitant rise in the LF/HF ratio in the RR interval (RRI) power spectrum. These results are in line with data available in literature thus providing a first support to the validity of our estimates. In the second experiment, we evaluated in one subject the feasibility of the beat-by-beat assessment of LVET during spontaneous behavior. The subject was continuously monitored by the smart garment from 8 am to 8 pm during a workday. From the whole recording, three data segments were selected: while the subject was traveling to work (M1), during work in the office (O) and while traveling back home (M2). LVET was estimated on a beat-by-beat basis from SCG and the RRI influence was removed by regression analysis. The LVET series displayed marked beat-by-beat fluctuations at the respiratory frequency. The amplitude of these fluctuations changed in the three periods and was lower when the LF/HF RRI power ratio was higher, at O, thus suggesting a possible influence of the autonomic nervous system on LVET short-term variability. To the best of our knowledge this case report provides for the first time a representation of the beat-by-beat dynamics of a systolic time interval during daily activity. The statistical characterization of these findings remains to be explored on a larger population. PMID:23664242

Di Rienzo, M; Vaini, E; Castiglioni, P; Merati, G; Meriggi, P; Parati, G; Faini, A; Rizzo, F

2013-11-01

184

Clinical trial enrollers vs. nonenrollers: The Cardiac Arrhythmia Suppression Trial (CAST) Recruitment and Enrollment Assessment in Clinical Trials (REACT) project  

Microsoft Academic Search

The Recruitment and Enrollment Assessment in Clinical Trials (REACT) was a National Heart, Lung, and Blood Institute (NHLBI)-sponsored substudy to the Cardiac Arrhythmia Suppression Trial (CAST). Two-hundred-sixty (260) patients who enrolled in CAST and 140 partially or fully eligible patients who did not enroll were compared across several parameters, including demographic variables, disease severity, psychosocial functioning, health beliefs, recruitment experience,

Larry Gorkin; Eleanor B. Schron; Kathy Handshaw; Steven Shea; Marguerite R. Kinney; Martha Branyon; Jeanne Campion; J. Thomas Bigger; Susan C. Sylvia; Jeanette Duggan; Mario Stylianou; Scott Lancaster; David K. Ahern; Michael J. Follick

1996-01-01

185

Detecting drug-induced prolongation of the QRS complex: New insights for cardiac safety assessment  

SciTech Connect

Background: Drugs slowing the conduction of the cardiac action potential and prolonging QRS complex duration by blocking the sodium current (I{sub Na}) may carry pro-arrhythmic risks. Due to the frequency-dependent block of I{sub Na}, this study assesses whether activity-related spontaneous increases in heart rate (HR) occurring during standard dog telemetry studies can be used to optimise the detection of class I antiarrhythmic-induced QRS prolongation. Methods: Telemetered dogs were orally dosed with quinidine (class Ia), mexiletine (class Ib) or flecainide (class Ic). QRS duration was determined standardly (5 beats averaged at rest) but also prior to and at the plateau of each acute increase in HR (3 beats averaged at steady state), and averaged over 1 h period from 1 h pre-dose to 5 h post-dose. Results: Compared to time-matched vehicle, at rest, only quinidine and flecainide induced increases in QRS duration (E{sub max} 13% and 20% respectively, P < 0.01–0.001) whereas mexiletine had no effect. Importantly, the increase in QRS duration was enhanced at peak HR with an additional effect of + 0.7 ± 0.5 ms (quinidine, NS), + 1.8 ± 0.8 ms (mexiletine, P < 0.05) and + 2.8 ± 0.8 ms (flecainide, P < 0.01) (calculated as QRS at basal HR-QRS at high HR). Conclusion: Electrocardiogram recordings during elevated HR, not considered during routine analysis optimised for detecting QT prolongation, can be used to sensitise the detection of QRS prolongation. This could prove useful when borderline QRS effects are detected. Analysing during acute increases in HR could also be useful for detecting drug-induced effects on other aspects of cardiac function. -- Highlights: ? We aimed to improve detection of drug-induced QRS prolongation in safety screening. ? We used telemetered dogs to test class I antiarrhythmics at low and high heart rate. ? At low heart rate only quinidine and flecainide induced an increase in QRS duration. ? At high heart rate the effects of two out of three antiarrhythmics were enhanced. ? Detection of a drug-induced prolongation of QRS was improved at high heart rate.

Cros, C., E-mail: caroline.cros@hotmail.co.uk [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Skinner, M., E-mail: Matthew.Skinner@astrazeneca.com [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Moors, J. [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)] [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom); Lainee, P. [Sanofi-Aventis R and D, 371, rue du Pr Joseph Blayac, 34184 Montpellier Cedex 04 (France)] [Sanofi-Aventis R and D, 371, rue du Pr Joseph Blayac, 34184 Montpellier Cedex 04 (France); Valentin, J.P. [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)] [Safety Pharmacology, Global Safety Assessment, Safety Assessment UK, AstraZeneca R and D, Alderley Park, Macclesfield, SK10 4TG (United Kingdom)

2012-12-01

186

Commutability of Possible External Quality Assessment Materials for Cardiac Troponin Measurement  

PubMed Central

Background The measurement of cardiac troponin is crucial in the diagnosis of myocardial infarction. The performance of troponin measurement is most conveniently monitored by external quality assessment (EQA) programs. The commutability of EQA samples is often unknown and the effectiveness of EQA programs is limited. Methods Commutability of possible EQA materials was evaluated. Commercial control materials used in an EQA program, human serum pools prepared from patient samples, purified analyte preparations, swine sera from model animals and a set of patient samples were measured for cTnI with 4 assays including Abbott Architect, Beckman Access, Ortho Vitros and Siemens Centaur. The measurement results were logarithm-transformed, and the transformed data for patient samples were pairwise analyzed with Deming regression and 95% prediction intervals were calculated for each pair of assays. The commutability of the materials was evaluated by comparing the logarithmic results of the materials with the limits of the intervals. Matrix-related biases were estimated for noncommutable materials. The impact of matrix-related bias on EQA was analyzed and a possible correction for the bias was proposed. Results Human serum pools were commutable for all assays; purified analyte preparations were commutable for 2 of the 6 assay pairs; commercial control materials and swine sera were all noncommutable; swine sera showed no reactivity to Vitros assay. The matrix-related biases for noncommutable materials ranged from ?83% to 944%. Matrix-related biases of the EQA materials caused major abnormal between-assay variations in the EQA program and correction of the biases normalized the variations. Conclusion Commutability of materials has major impact on the effectiveness of EQA programs for cTnI measurement. Human serum pools prepared from patient samples are commutable and other materials are mostly noncommutable. EQA programs should include at least one human serum pool to allow proper interpretation of EQA results. PMID:25000586

Zhang, Shunli; Zeng, Jie; Zhang, Chuanbao; Li, Yilong; Zhao, Haijian; Cheng, Fei; Yu, Songlin; Wang, Mo; Chen, Wenxiang

2014-01-01

187

Non-invasive assessment of cardiac function and pulmonary vascular resistance in an canine model of acute thromboembolic pulmonary hypertension using 4D flow cardiovascular magnetic resonance  

PubMed Central

Background The purpose of this study was to quantify right (RV) and left (LV) ventricular function, pulmonary artery flow (QP), tricuspid valve regurgitation velocity (TRV), and aorta flow (QS) from a single 4D flow cardiovascular magnetic resonance (CMR) (time-resolved three-directionally motion encoded CMR) sequence in a canine model of acute thromboembolic pulmonary hypertension (PH). Methods Acute PH was induced in six female beagles by microbead injection into the right atrium. Pulmonary arterial (PAP) and pulmonary capillary wedge (PCWP) pressures and cardiac output (CO) were measured by right heart catheterization (RHC) at baseline and following induction of acute PH. Pulmonary vascular resistance (PVRRHC) was calculated from RHC values of PAP, PCWP and CO (PVRRHC?=?(PAP-PCWP)/CO). Cardiac magnetic resonance (CMR) was performed on a 3 T scanner at baseline and following induction of acute PH. RV and LV end-diastolic (EDV) and end-systolic (ESV) volumes were determined from both CINE balanced steady-state free precession (bSSFP) and 4D flow CMR magnitude images. QP, TRV, and QS were determined from manually placed cutplanes in the 4D flow CMR flow-sensitive images in the main (MPA), right (RPA), and left (LPA) pulmonary arteries, the tricuspid valve (TRV), and aorta respectively. MPA, RPA, and LPA flow was also measured using two-dimensional flow-sensitive (2D flow) CMR. Results Biases between 4D flow CMR and bSSFP were 0.8 mL and 1.6 mL for RV EDV and RV ESV, respectively, and 0.8 mL and 4 mL for LV EDV and LV ESV, respectively. Flow in the MPA, RPA, and LPA did not change after induction of acute PAH (p?=?0.42-0.81). MPA, RPA, and LPA flow determined with 4D flow CMR was significantly lower than with 2D flow (p?cardiac function and cardiopulmonary hemodynamic parameters important in the assessment of PH. PMID:24625242

2014-01-01

188

Noninvasive assessment of cardiac abnormalities in experimental autoimmune myocarditis by magnetic resonance microscopy imaging in the mouse.  

PubMed

Myocarditis is an inflammation of the myocardium, but only -10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-? 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-? 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies. PMID:24998332

Massilamany, Chandirasegaran; Khalilzad-Sharghi, Vahid; Gangaplara, Arunakumar; Steffen, David; Othman, Shadi F; Reddy, Jay

2014-01-01

189

Sympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans  

NASA Technical Reports Server (NTRS)

Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 frequencies, from 15 to 3 breaths/min, before and after beta-adrenergic blockade. We fitted changes of respiratory frequency R-R interval spectral power with a damped oscillator model: frequency-dependent oscillations with a resonant frequency, generated by driving forces and modified by damping influences. beta-Adrenergic blockade enhanced respiratory sinus arrhythmia at all frequencies (at some, fourfold). The damped oscillator model fit experimental data well (39 of 40 ramps; r = 0.86 +/- 0.02). beta-Adrenergic blockade increased respiratory sinus arrhythmia by amplifying respiration-related driving forces (P < 0.05), without altering resonant frequency or damping influences. Both spectral power data and the damped oscillator model indicate that cardiac sympathetic outflow markedly reduces heart period oscillations at all frequencies. This challenges the notion that respiratory sinus arrhythmia is mediated simply by vagal-cardiac nerve activity. These results have important implications for clinical and experimental estimation of human vagal cardiac tone.

Taylor, J. A.; Myers, C. W.; Halliwill, J. R.; Seidel, H.; Eckberg, D. L.

2001-01-01

190

Quantitative EEG assessment of brain injury and hypothermic neuroprotection after cardiac arrest.  

PubMed

In this paper we provide a quantitative electroencephalogram (EEG) analysis to study the effect of hypothermia on the neurological recovery of brain after cardiac arrest. We hypothesize that the brain injury results in a reduction in information of the brain rhythm. To measure the information content of the EEG a new measure called information quantity (IQ), which is the Shannon entropy of decorrelated EEG signals, is developed. For decorrelating EEG signals, we use the discrete wavelet transform (DWT) which is known to have good decorrelating properties and to show a good match to the standard clinical bands in EEG. In simulation for measuring the amount of information, the IQ shows better tracking capability for dynamic amplitude change and frequency component change than conventional entropy-based measures. Experiments are carried out in rodents to monitor the neurological recovery after cardiac arrest. In addition, EEG signal recovery under normothermic (37 degrees C) and hypothermic (33 degrees C) resuscitation following 5, 7 and 9 minutes of cardiac arrest is recorded and analyzed. Experimental results show that the IQ is higher for hypothermic than normothermic rats. The results quantitatively support the hypothesis that hypothermia accelerates the recovery of brain injury after cardiac arrest. PMID:17947182

Shin, Hyun-Chool; Tong, Shanbao; Yamashita, Soichiro; Jia, Xiaofeng; Geocadin, Romergryko G; Thakor, Nitish V

2006-01-01

191

CARDIAC MR IMAGE SEGMENTATION: QUALITY ASSESSMENT OF STACS Charnchai Pluempitiwiriyawej and Jose M. F. Moura  

E-print Network

) is perceivably undistin- guishable from the texture of other heart structures and anatomy parts's heart, STACS correctly segments the heart region (my- ocardium) from other anatomy parts. This work Cardiac MR image segmentation is challenging because the tex- ture of the myocardium (the heart muscle

Moura, José

192

Missed cardiac tamponade  

PubMed Central

Cardiac tamponade can have an insidious onset, becoming life threatening when an adequate cardiac output can no longer be maintained. This case provides an example of a presentation where all the classic signs were present but unfortunately they were missed, in this way providing good revision of what these signs are. It gives some anaesthetic and procedure based perspectives for this rare presentation. It is noteworthy for the speed at which symptoms and signs resolved after the tamponade was relieved. PMID:22679253

Thomson-Moore, Alexandra Louise

2011-01-01

193

Assessment of Long-Term Climate Change Impacts on Agricultural Productivity in Eastern China Using High-Resolution Regional Climate Model Output  

Microsoft Academic Search

Increasing atmospheric greenhouse gas concentrations are expected to induce significant climate change over the next century and beyond, but the impacts on society remain highly uncertain. This work utilizes high-resolution regional climate model output to assess potential climate change impacts on the productivity of five major crops in eastern China: canola, corn, potato, rice, and winter wheat. In addition to

D. R. Chavas; C. Izaurralde; A. Thomson

2008-01-01

194

Cardiac and peripheral vascular contributions to hypotension in spinal cats.  

PubMed

On transection of the cervical spinal cord, substantial decreases in systemic arterial pressure and in discharge of many sympathetic nerves suggest the absence of sympathetic support to the cardiovascular system. However, discharge of mesenteric and splenic nerves is well maintained in spinal cats (R. L. Meckler and L. C. Weaver. J. Physiol. Lond. 396: 139-153, 1988; R. D. Stein and L. C. Weaver. J. Physiol. Lond. 396: 155-172, 1988). We proposed that the low arterial pressure in spinal animals was caused predominantly by decreased cardiac output and vasodilation in muscle and some visceral vascular beds but that sustained mesenteric and splenic discharge was causing significant splanchnic vasoconstriction and partial support of arterial pressure. Therefore, changes in cardiac output, total peripheral resistance, and resistance of constant-flow-perfused mesenteric visceral and hindlimb skeletal muscle vascular beds caused by interruption of cervical spinal pathways were assessed. Blockade of cervical pathways decreased arterial pressure as much by decreasing cardiac output as by decreasing total peripheral resistance. Resistances of the muscle and mesenteric vascular beds decreased equally. In conclusion, hypotension in spinal cats is caused by decreased cardiac output and by vasodilation, which is as prominent in mesenteric as it is in muscle vascular beds. The maintained mesenteric sympathetic discharge in spinal cats appears unable to produce significant support of vascular arterial resistance. PMID:2589489

Yardley, C P; Fitzsimons, C L; Weaver, L C

1989-11-01

195

Assessing quality in cardiac surgery: why this is necessary in the twenty-first century  

NASA Technical Reports Server (NTRS)

The cost and high-profile nature of coronary surgery means that this is an area of close public scrutiny. As much pioneering work in data collection and risk analyses has been carried out by cardiac surgeons, substantial information exists and the correct interpretation of that data is identified as an important issue. This paper considers the background and history of risk-adjustment in cardiac surgery, the uses of quality data, examines the observed/expected mortality ratio and looks at issues such as cost and reactions to outliers. The conclusion of the study is that the continuation of accurate data collection by the whole operative team and a strong commitment to constantly improving quality is crucial to its meaningful application.

Swain, J. A.; Hartz, R. S.

2000-01-01

196

Limitations of Early Serum Creatinine Variations for the Assessment of Kidney Injury in Neonates and Infants with Cardiac Surgery  

PubMed Central

Background Changes in kidney function, as assessed by early and even small variations in serum creatinine (?sCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ?sCr in infants undergoing cardiac surgery. Methodology The ability of ?sCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ? 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death. Results Three clusters of ?sCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ? 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ? 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ?sCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model. Conclusions The present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury. PMID:24244476

Bojan, Mirela; Lopez-Lopez, Vanessa; Pouard, Philippe; Falissard, Bruno; Journois, Didier

2013-01-01

197

Assessment of Procalcitonin to Predict Outcome in Hypothermia-Treated Patients after Cardiac Arrest  

PubMed Central

Objective. Determine the potential of procalcitonin (PCT) to predict neurological outcome after hypothermia treatment following cardiac arrest. Methods. Retrospective analysis of patient data over a 2-year period. Mortality and neurological outcome of survivors were determined 6 months after cardiac arrest using the Cerebral Performance Category (CPC) score. Results. Data from 53 consecutive patients were analyzed. Median age was 63 (54–71) and 79% were male. Twenty-seven patients had good outcome (CPC???2) whereas 26 had severe neurological sequelae or died (CPC 3–5). At 48?h, after regaining normothermia, PCT was significantly higher in patients with bad outcome compared to those with good outcome: 3.38 (1.10–24.48) versus 0.28 (0–0.75)?ng/mL (P < 0.001). PCT values correlated with bad neurological outcome (r = 0.54, P = 0.00004) and predicted outcome with an area under the curve of 0.84 (95% CI 0.73–0.96). A cutoff point of 1?ng/mL provided a sensitivity of 85% and a specificity of 81%. Above a PCT level of 16?ng/mL, no patient regained consciousness. PCT provided an additive value over simplified acute physiology score II. Conclusions. PCT might be an ancillary marker for outcome prediction after cardiac arrest treated by induced hypothermia. PMID:22110909

Stammet, Pascal; Devaux, Yvan; Azuaje, Francisco; Werer, Christophe; Lorang, Christiane; Gilson, Georges; Max, Martin

2011-01-01

198

A time-saving method to assess power output at lactate threshold in well-trained and elite cyclists.  

PubMed

The purpose of this study was to examine the relationship between lactate threshold (LT) as a percentage of maximal oxygen consumption (V[Combining Dot Above]O2max) and power output at LT (LTW) and also to investigate to what extent V[Combining Dot Above]O2max, oxygen cost of cycling (CC), and maximal aerobic power (MAP) determine LTW in cycling to develop a new time-saving model for testing LTW. To do this, 108 male competitive cyclists with an average V[Combining Dot Above]O2max of 65.2 ± 7.4 ml·kg·min and an average LTW of 274 ± 43 W were tested for V[Combining Dot Above]O2max, LT %V[Combining Dot Above]O2max, LTW, MAP, and CC on a test ergometer cycle. The product of MAP and individual LT in %V[Combining Dot Above]O2max was found to be a good determinant of LTW (R = 0.98, p < 0.0001). However, LT in %V[Combining Dot Above]O2max was found to be a poor determinant of LTW (R = 0.39, p < 0.0001). Based on these findings, we have suggested a new time-saving method for calculating LTW in well-trained cyclists. The benefits from this model come both from tracking LTW during training interventions and from regularly assessing training status in competitive cyclists. Briefly, this method is based on the present findings that LTW depends on LT in %V[Combining Dot Above]O2max, V[Combining Dot Above]O2max, and CC and may after an initial test session reduce the time for the subsequent testing of LTW by as much as 50% without the need for blood samples. PMID:23942166

Støren, Øyvind; Rønnestad, Bent R; Sunde, Arnstein; Hansen, Joar; Ellefsen, Stian; Helgerud, Jan

2014-03-01

199

Assessment of cardiac proteome dynamics with heavy water: slower protein synthesis rates in interfibrillar than subsarcolemmal mitochondria  

PubMed Central

Traditional proteomics provides static assessment of protein content, but not synthetic rates. Recently, proteome dynamics with heavy water (2H2O) was introduced, where 2H labels amino acids that are incorporated into proteins, and the synthesis rate of individual proteins is calculated using mass isotopomer distribution analysis. We refine this approach with a novel algorithm and rigorous selection criteria that improve the accuracy and precision of the calculation of synthesis rates and use it to measure protein kinetics in spatially distinct cardiac mitochondrial subpopulations. Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) were isolated from adult rats, which were given 2H2O in the drinking water for up to 60 days. Plasma 2H2O and myocardial 2H-enrichment of amino acids were stable throughout the experimental protocol. Multiple tryptic peptides were identified from 28 proteins in both SSM and IFM and showed a time-dependent increase in heavy mass isotopomers that was consistent within a given protein. Mitochondrial protein synthesis was relatively slow (average half-life of 30 days, 2.4% per day). Although the synthesis rates for individual proteins were correlated between IFM and SSM (R2 = 0.84; P < 0.0001), values in IFM were 15% less than SSM (P < 0.001). In conclusion, administration of 2H2O results in stable enrichment of the cardiac precursor amino acid pool, with the use of refined analytical and computational methods coupled with cell fractionation one can measure synthesis rates for cardiac proteins in subcellular compartments in vivo, and protein synthesis is slower in mitochondria located among the myofibrils than in the subsarcolemmal region. PMID:23457012

Dabkowski, Erinne R.; Shekar, Kadambari Chandra; Li, Ling; Ribeiro, Rogerio F.; Walsh, Kenneth; Previs, Stephen F.; Sadygov, Rovshan G.; Willard, Belinda; Stanley, William C.

2013-01-01

200

The Assessment of Inequality on Geographical Distribution of Non-Cardiac Intensive Care Beds in Iran  

PubMed Central

Background: The purpose of the present study was to evaluate the inequality of geographical distribution of non-cardiac intensive care beds in Iran using the Gini coefficient. Methods: The population information of Iran’s provinces in 2006 was obtained from The Statistical Center of Iran and the number of non-cardiac intensive care beds (including ICU, PostICU and NICU beds) in all provinces was taken from published information of Ministry of Health and Medical Education of Iran in the current year. The number of beds per 100,000 populations of each province and the Gini coefficients for each bed were calculated. Results: Iran’s population was 70,495,782. The total number of ICU, PostICU and NICU beds were 3720, 291 and 1129, respectively. Tehran had the highest percentage of each bed among all provinces. The number of each bed was 5.3, 0.4 and 1.6 per 100,000 populations of country, respectively. The calculated Gini coefficients for each bed were 0.17, 0.15 and 0.23, respectively. Conclusion: The findings of this study showed that, according to the Gini coefficients, non-cardiac intensive care beds have an almost equal geographical distribution throughout the country. However, the numbers of beds per population are less than other countries. Since such studies can be used as a base for health systems planning about correction of inequality of health services distribution, similar studies in other health care services are recommended which can be conducted at the national or provincial level. PMID:23113070

Ameryoun, A; Meskarpour-Amiri, M; Dezfuli-Nejad, M Lorgard; Khoddami-Vishteh, HR; Tofighi, Sh

2011-01-01

201

Cardiac assessment of veteran endurance athletes: a 12 year follow up study  

PubMed Central

OBJECTIVES: Sustained aerobic dynamic exercise is beneficial in preventing cardiovascular disease. The effect of lifelong endurance exercise on cardiac structure and function is less well documented, however. A 12 year follow up of 20 veteran athletes was performed, as longitudinal studies in such cohorts are rare. METHODS: Routine echocardiography was repeated as was resting, exercise, and 24 hour electrocardiography. RESULTS: Nineteen returned for screening. Mean (SD) age was 67 (6.2) years (range 56-83). Two individuals had had permanent pacemakers implanted (one for symptomatic atrial fibrillation with complete heart block, the other for asystole lasting up to 15 seconds). Only two athletes had asystolic pauses in excess of two seconds compared with seven athletes in 1985. Of these seven, five had no asystole on follow up. Two of these five had reduced their average running distance by about 15-20 miles a week. One athlete sustained an acute myocardial infarction during a competitive race in 1988. Three athletes had undergone coronary arteriography during the 12 years of follow up but none had obstructive coronary artery disease. Ten of 19 (53%) had echo evidence of left ventricular hypertrophy in 1997 but only two (11%) had left ventricular dilatation. Ten athletes had ventricular couplets on follow up compared with only two in 1985. CONCLUSIONS: Although the benefits of moderate regular exercise are undisputed, high intensity lifelong endurance exercise may be associated with altered cardiac structure and function. These adaptations to more extreme forms of exercise merit caution in the interpretation of standard cardiac investigations in the older athletic population. On rare occasions, these changes may be deleterious. ??? PMID:10450477

Hood, S.; Northcote, R. J.

1999-01-01

202

Real time assessment of RF cardiac tissue ablation with optical spectroscopy  

SciTech Connect

An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, catheter-tissue proximity, lesion formation, depth of penetration of the lesion, formation of char during the ablation, formation of coagulum around the ablation site, differentiation of ablated from healthy tissue, and recognition of micro-bubble formation in the tissue.

Demos, S G; Sharareh, S

2008-03-20

203

Databases for assessing the outcomes of the treatment of patients with congenital and paediatric cardiac disease--the perspective of cardiac surgery.  

PubMed

This review includes a brief discussion, from the perspective of cardiac surgeons, of the rationale for creation and maintenance of multi-institutional databases of outcomes of congenital heart surgery, together with a history of the evolution of such databases, a description of the current state of the art, and a discussion of areas for improvement and future expansion of the concept. Five fundamental areas are reviewed: nomenclature, mechanism of data collection and storage, mechanisms for the evaluation and comparison of the complexity of operations and stratification of risk, mechanisms to ensure the completeness and accuracy of the data, and mechanisms for expansion of the current capabilities of databases to include comparison and sharing of data between medical subspecialties. This review briefly describes several European and North American initiatives related to databases for pediatric and congenital cardiac surgery the Congenital Database of The European Association for Cardio-Thoracic Surgery, the Congenital Database of The Society of Thoracic Surgeons, the Pediatric Cardiac Care Consortium, and the Central Cardiac Audit Database in the United Kingdom. Potential means of approaching the ultimate goal of acquisition of long-term follow-up data, and input of this data over the life of the patient, are also considered. PMID:19063780

Jacobs, Marshall Lewis; Jacobs, Jeffrey Phillip; Franklin, Rodney C G; Mavroudis, Constantine; Lacour-Gayet, Francois; Tchervenkov, Christo I; Walters, Hal; Bacha, Emile A; Clarke, David Robinson; William Gaynor, J; Spray, Thomas L; Stellin, Giovanni; Ebels, Tjark; Maruszewski, Bohdan; Tobota, Zdzislaw; Kurosawa, Hiromi; Elliott, Martin

2008-12-01

204

Morphological and Volumetric Analysis of Left Atrial Appendage and Left Atrium: Cardiac Computed Tomography-Based Reproducibility Assessment  

PubMed Central

Objectives Left atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments. Methods A total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N?=?40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A?=?Cactus, B?=?ChickenWing, C?=?WindSock, D?=?CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa. Results The intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC?=?0.954) and LA (ICC?=?0.945) volume measurements were comparable between 2CV and TV. Morphological classification (??=?0.24) and assessments of LAA opening height (??=?0.1), number of LAA lobes (??=?0.16), trabeculation (??=?0.15), and orientation of the LAA tip (??=?0.37) was only slightly to fairly reproducible. Conclusions LA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers. PMID:24988467

Taina, Mikko; Korhonen, Miika; Haataja, Mika; Muuronen, Antti; Arponen, Otso; Hedman, Marja; Jäkälä, Pekka; Sipola, Petri; Mustonen, Pirjo; Vanninen, Ritva

2014-01-01

205

Safety assessment and biodistribution of povidone as a coating material for cardiac pacing leads.  

PubMed

Cardiac pacing leads coated with povidone-[131I] were implanted in dogs and the leaching of radioactivity from the leads was monitored by external scintigraphy. The activity which had dissipated from the pacing leads was not as [131I]-iodide, but as povidone-[131I]. Only 50% (mean) of the activity remained on the pacing leads after two weeks while a significant amount of radioactivity was eliminated via urine and feces. The liver was a major site of accumulation of retained activity which had leached off the pacing leads. There was no evidence of large pieces of povidone-[131I] in the lungs of the dogs, all of which appeared healthy at the time of sacrifice. The results of this study support the conclusions of a long-term study indicating that povidone is a safe and suitable coating material for pacing leads. PMID:6679796

Jay, M; Digenis, G A

206

Predictive Value of Assessing Diastolic Strain Rate on Survival in Cardiac Amyloidosis Patients with Preserved Ejection Fraction  

PubMed Central

Objectives Since diastolic abnormalities are typical findings of cardiac amyloidosis (CA), we hypothesized that speckle-tracking-imaging (STI) derived longitudinal early diastolic strain rate (LSRdias) could predict outcome in CA patients with preserved left ventricular ejection fraction (LVEF >50%). Background Diastolic abnormalities including altered early filling are typical findings and are related to outcome in CA patients. Reduced longitudinal systolic strain (LSsys) assessed by STI predicts increased mortality in CA patients. It remains unknown if LSRdias also related to outcome in these patients. Methods Conventional echocardiography and STI were performed in 41 CA patients with preserved LVEF (25 male; mean age 65±9 years). Global and segmental LSsys and LSRdias were obtained in six LV segments from apical 4-chamber views. Results Nineteen (46%) out of 41 CA patients died during a median of 16 months (quartiles 5–35 months) follow-up. Baseline mitral annular plane systolic excursion (MAPSE, 6±2 vs. 8±3 mm), global LSRdias and basal-septal LSRdias were significantly lower in non-survivors than in survivors (all p<0.05). NYHA class, number of non-cardiac organs involved, MAPSE, mid-septal LSsys, global LSRdias, basal-septal LSRdias and E/LSRdias were the univariable predictors of all-cause death. Multivariable analysis showed that number of non-cardiac organs involved (hazard ratio [HR] ?=?1.96, 95% confidence interval [CI] 1.17–3.26, P?=?0.010), global LSRdias (HR?=?7.30, 95% CI 2.08–25.65, P?=?0.002), and E/LSRdias (HR?=?2.98, 95% CI 1.54–5.79, P?=?0.001) remained independently predictive of increased mortality risk. The prognostic performance of global LSRdias was optimal at a cutoff value of 0.85 S?1 (sensitivity 68%, specificity 67%). Global LSRdias <0.85 S?1 predicted a 4-fold increased mortality in CA patients with preserved LVEF. Conclusions STI-derived early diastolic strain rate is a powerful independent predictor of survival in CA patients with preserved LVEF. PMID:25542015

Störk, Stefan; Herrmann, Sebastian; Kramer, Bastian; Cikes, Maja; Gaudron, Philipp Daniel; Knop, Stefan; Ertl, Georg; Bijnens, Bart; Weidemann, Frank

2014-01-01

207

Preoperative and long-term cardiac risk assessment. Predictive value of 23 clinical descriptors, 7 multivariate scoring systems, and quantitative dipyridamole imaging in 360 patients.  

PubMed Central

A total of 360 patients underwent preoperative cardiac risk assessment using 23 clinical parameters, seven multivariate clinical scoring systems, and quantitative dipyridamole-thallium imaging to predict postoperative and long-term myocardial infarction and cardiac death after noncardiac surgery. There were 30 postoperative and an additional 13 cumulative long-term cardiac events after an average follow-up of 15 months. Clinical descriptors were not useful in predicting the outcome of individual patients. The postoperative and long-term cardiac event rates were 1% and 3.5%, respectively, in patients with normal scans or fixed perfusion defects, and 17.5% and 22% in patients with reversible defects. Using quantitative indices reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into multiple scintigraphic subsets, with corresponding postoperative and 1-year coronary morbidity and mortality rates ranging from 0.5% to 100% (p = 0.0001). Thus, postoperative and long-term cardiac events cannot be predicted clinically, whereas quantitative dipyridamole imaging accurately identifies high-risk patients who require preoperative coronary angiography. PMID:1503520

Lette, J; Waters, D; Bernier, H; Champagne, P; Lassonde, J; Picard, M; Cerino, M; Nattel, S; Boucher, Y; Heyen, F

1992-01-01

208

Late cardiac sodium current can be assessed using automated patch-clamp  

PubMed Central

The cardiac late Na + current is generated by a small fraction of voltage-dependent Na + channels that undergo a conformational change to a burst-gating mode, with repeated openings and closures during the action potential (AP) plateau. Its magnitude can be augmented by inactivation-defective mutations, myocardial ischemia, or prolonged exposure to chemical compounds leading to drug-induced (di)-long QT syndrome, and results in an increased susceptibility to cardiac arrhythmias. Using CytoPatch™ 2 automated patch-clamp equipment, we performed whole-cell recordings in HEK293 cells stably expressing human Nav1.5, and measured the late Na + component as average current over the last 100 ms of 300 ms depolarizing pulses to -10 mV from a holding potential of -100 mV, with a repetition frequency of 0.33 Hz. Averaged values in different steady-state experimental conditions were further corrected by the subtraction of current average during the application of tetrodotoxin (TTX) 30 ?M. We show that ranolazine at 10 and 30 ?M in 3 min applications reduced the late Na + current to 75.0 ± 2.7% (mean ± SEM, n = 17) and 58.4 ± 3.5% ( n = 18) of initial levels, respectively, while a 5 min application of veratridine 1 ?M resulted in a reversible current increase to 269.1 ± 16.1% ( n = 28) of initial values. Using fluctuation analysis, we observed that ranolazine 30 ?M decreased mean open probability p from 0.6 to 0.38 without modifying the number of active channels n, while veratridine 1 ?M increased n 2.5-fold without changing p. In human iPSC-derived cardiomyocytes, veratridine 1 ?M reversibly increased APD90 2.12 ± 0.41-fold (mean ± SEM, n = 6). This effect is attributable to inactivation removal in Nav1.5 channels, since significant inhibitory effects on hERG current were detected at higher concentrations in hERG-expressing HEK293 cells, with a 28.9 ± 6.0% inhibition (mean ± SD, n = 10) with 50 ?M veratridine.        PMID:25383189

Gawali, Vaibhavkumar; Todt, Hannes; Knott, Thomas; Scheel, Olaf; Abriel, Hugues

2014-01-01

209

Variability in high-throughput ion-channel screening data and consequences for cardiac safety assessment  

PubMed Central

Introduction Unwanted drug interactions with ionic currents in the heart can lead to an increased proarrhythmic risk to patients in the clinic. It is therefore a priority for safety pharmacology teams to detect block of cardiac ion channels, and new technologies have enabled the development of automated and high-throughput screening assays using cell lines. As a result of screening multiple ion-channels there is a need to integrate information, particularly for compounds affecting more than one current, and mathematical electrophysiology in-silico action potential models are beginning to be used for this. Methods We quantified the variability associated with concentration-effect curves fitted to recordings from high-throughput Molecular Devices IonWorks® Quattro™ screens when detecting block of IKr (hERG), INa (NaV1.5), ICaL (CaV1.2), IKs (KCNQ1/minK) and Ito (Kv4.3/KChIP2.2), and the Molecular Devices FLIPR® Tetra fluorescence screen for ICaL (CaV1.2), for control compounds used at AstraZeneca and GlaxoSmithKline. We examined how screening variability propagates through in-silico action potential models for whole cell electrical behaviour, and how confidence intervals on model predictions can be estimated with repeated simulations. Results There are significant levels of variability associated with high-throughput ion channel electrophysiology screens. This variability is of a similar magnitude for different cardiac ion currents and different compounds. Uncertainty in the Hill coefficients of reported concentration-effect curves is particularly high. Depending on a compound’s ion channel blocking profile, the uncertainty introduced into whole-cell predictions can become significant. Discussion Our technique allows confidence intervals to be placed on computational model predictions that are based on high-throughput ion channel screens. This allows us to suggest when repeated screens should be performed to reduce uncertainty in a compound’s action to acceptable levels, to allow a meaningful interpretation of the data. PMID:23651875

Elkins, Ryan C.; Davies, Mark R.; Brough, Stephen J.; Gavaghan, David J.; Cui, Yi; Abi-Gerges, Najah; Mirams, Gary R.

2014-01-01

210

Comparison of cardiac function and coronary angiography between conventional pigs and micropigs as measured by multidetector row computed tomography  

PubMed Central

Pigs are the most likely source animals for cardiac xenotransplantation. However, an appropriate method for estimating the cardiac function of micropigs had not been established. Computed tomography (CT) analysis aimed at estimating cardiac function and assessing the coronary arteries has not been carried out in micropigs. This study determined the feasibility of evaluating cardiac function in a micropig model using multidetector row computed tomography (MDCT) and compared the cardiac function values with those of conventional pigs. The mean age of the conventional pigs and micropigs was approximately 80 days and approximately 360 days, respectively. The mean body weight in the conventional pigs and micropigs was 29.70 ± 0.73 and 34.10 ± 0.98 kg, respectively. Cardiac MDCT detected ejection fractions of 52.93 ± 3.10% and 59.00 ± 5.56% and cardiac outputs of 1.46 ± 0.64 l/min and 1.21 ± 0.24 l/min in conventional pigs and micropigs, respectively. There were no significant differences in cardiac function between conventional pigs and micropigs in the reconstructed CT images. There were also no differences in the coronary angiographic images obtained by MDCT. It is expected that the results of this study will help improve understanding of cardiac function in micropigs. The data presented in this study suggest that MDCT is a feasible method for evaluating cardiac function in micropigs. PMID:18487932

Ahn, Young Keun; Ryu, Jung Min; Jeong, Hea Chang; Kim, Yun Hyeon; Jeong, Myung Ho; Lee, Min Young; Lee, Sang Hun; Park, Jae Hong; Yun, Seung Pil

2008-01-01

211

Cardiac Assessment Risk Evaluation (Care Study) of African American College Women  

ERIC Educational Resources Information Center

Objective: To identify physiological and psychosocial variables of young African American women that may serve as a risk factor for heart disease and to assess their health promotion programme preferences. Method: A descriptive design was used to assess the cardiovascular risk factors of 100 African American women ages 18 to 40 years, enrolled in…

Brown, Sandra C.; Geiselman, Paula J.; Copeland, Amy L.; Gordon, Carol; Dudley, Mary; Manogin, Toni; Backstedt, Carol; Pourciau, Cathi; Ghebretatios, Ghenet

2005-01-01

212

Cardiac fiber unfolding by semidefinite programming.  

PubMed

Diffusion-tensor imaging allows noninvasive assessment of the myocardial fiber architecture, which is fundamental in understanding the mechanics of the heart. In this context, tractography techniques are often used for representing and visualizing cardiac fibers, but their output is only qualitative. We introduce here a new framework toward a more quantitative description of the cardiac fiber architecture from tractography results. The proposed approach consists in taking three-dimensional (3-D) fiber tracts as inputs, and then unfolding these fibers in the Euclidean plane under local isometry constraints using semidefinite programming. The solution of the unfolding problem takes the form of a Gram matrix which defines the two-dimensional (2-D) embedding of the fibers and whose spectrum provides quantitative information on their organization. Experiments on synthetic and real data show that unfolding makes it easier to observe and to study the cardiac fiber architecture. Our conclusion is that 2-D embedding of cardiac fibers is a promising approach to supplement 3-D rendering for understanding the functioning of the heart. PMID:25291787

Li, Hongying; Robini, Marc C; Yang, Feng; Magnin, Isabelle; Zhu, Yuemin

2015-02-01

213

Left ventricular modelling: a quantitative functional assessment tool based on cardiac magnetic resonance imaging  

PubMed Central

We present the development and testing of a semi-automated tool to support the diagnosis of left ventricle (LV) dysfunctions from cardiac magnetic resonance (CMR). CMR short-axis images of the LVs were obtained in 15 patients and processed to detect endocardial and epicardial contours and compute volume, mass and regional wall motion (WM). Results were compared with those obtained from manual tracing by an expert cardiologist. Nearest neighbour tracking and finite-element theory were merged to calculate local myocardial strains and torsion. The method was tested on a virtual phantom, on a healthy LV and on two ischaemic LVs with different severity of the pathology. Automated analysis of CMR data was feasible in 13/15 patients: computed LV volumes and wall mass correlated well with manually extracted data. The detection of regional WM abnormalities showed good sensitivity (77.8%), specificity (85.1%) and accuracy (82%). On the virtual phantom, computed local strains differed by less than 14 per cent from the results of commercial finite-element solver. Strain calculation on the healthy LV showed uniform and synchronized circumferential strains, with peak shortening of about 20 per cent at end systole, progressively higher systolic wall thickening going from base to apex, and a 10° torsion. In the two pathological LVs, synchronicity and homogeneity were partially lost, anomalies being more evident for the more severely injured LV. Moreover, LV torsion was dramatically reduced. Preliminary testing confirmed the validity of our approach, which allowed for the fast analysis of LV function, even though future improvements are possible. PMID:22670208

Conti, C. A.; Votta, E.; Corsi, C.; De Marchi, D.; Tarroni, G.; Stevanella, M.; Lombardi, M.; Parodi, O.; Caiani, E. G.; Redaelli, A.

2011-01-01

214

Assessment of New Immunosuppressive Drugs in a Rat Cardiac Allograft Heterotopic Model  

Microsoft Academic Search

We assessed FK506 (FK) and rapamycin (RPM) in a heterotopic abdominal rat heart transplant model using a major histocompatibility mismatch (DA to LEW). The end point of our study was histologic grading of rejection (Billingham and working formulation) at 1 week. Two doses of FK (2.0 and 8.0mg\\/kg p.o., q.d.) and RPM (1.5 and 6.0mg\\/kg i.p., q.d.) were compared to

B. Walpoth; J. Galdikas; T. Vorburger; H. J. Altermatt; T. Schaffner; U. Althaus; M. Billingham; R. Morris

1992-01-01

215

Fetal cardiac tumors: prenatal diagnosis and outcome.  

PubMed

We present our experience in the management of fetuses diagnosed with huge cardiac tumors. These cases illustrate that the size of the tumor likely does not impact on survival as much as the location of the tumor and how it compromises blood flow into and out of the ventricles. We speculate that obstruction of right-sided inflow and/or simultaneous obstruction to outflow from both ventricles may lead to diminished cardiac output, atrial and caval hypertension, and hydrops fetalis. Obstruction can occur at any point in gestation and depends on both the size and the location of the tumor in relation to all cardiac structures. We therefore suggest serial assessment of these fetuses throughout gestation, particularly after the point of postnatal viability, to assess the hemodynamic effects that the tumor has on the heart. If obstruction to blood flow and/or early fetal compromise is noted, then the decision of whether to deliver early can be made. At the time of birth, if obstruction to blood flow persists, surgery can be considered, keeping in mind that the natural history of these tumors is to shrink and become clinically less important over time. PMID:17308946

Lacey, S R; Donofrio, M T

2007-01-01

216

Cardiac Magnetic Resonance Assessment of Interstitial Myocardial Fibrosis and Cardiomyocyte Hypertrophy in Hypertensive Mice Treated With Spironolactone  

PubMed Central

Background Nearly 50% of patients with heart failure (HF) have preserved LV ejection fraction, with interstitial fibrosis and cardiomyocyte hypertrophy as early manifestations of pressure overload. However, methods to assess both tissue characteristics dynamically and noninvasively with therapy are lacking. We measured the effects of mineralocorticoid receptor blockade on tissue phenotypes in LV pressure overload using cardiac magnetic resonance (CMR). Methods and Results Mice were randomized to l?nitro???methyl ester (l?NAME, 3 mg/mL in water; n=22), or l?NAME with spironolactone (50 mg/kg/day in subcutaneous pellets; n=21). Myocardial extracellular volume (ECV; marker of diffuse interstitial fibrosis) and the intracellular lifetime of water (?ic; marker of cardiomyocyte hypertrophy) were determined by CMR T1 imaging at baseline and after 7 weeks of therapy alongside histological assessments. Administration of l?NAME induced hypertensive heart disease in mice, with increases in mean arterial pressure, LV mass, ECV, and ?ic compared with placebo?treated controls, while LV ejection fraction was preserved (>50%). In comparison, animals receiving both spironolactone and l?NAME (“l?NAME+S”) showed less concentric remodeling, and a lower myocardial ECV and ?ic, indicating decreased interstitial fibrosis and cardiomyocyte hypertrophy (ECV: 0.43±0.09 for l?NAME versus 0.25±0.03 for l?NAME+S, P<0.001; ?ic: 0.42±0.11 for l?NAME groups versus 0.12±0.05 for l?NAME+S group). Mice treated with a combination of l?NAME and spironolactone were similar to placebo?treated controls at 7 weeks. Conclusions Spironolactone attenuates interstitial fibrosis and cardiomyocyte hypertrophy in hypertensive heart disease. CMR can phenotype myocardial tissue remodeling in pressure?overload, furthering our understanding of HF progression. PMID:24965024

Coelho?Filho, Otavio R.; Shah, Ravi V.; Neilan, Tomas G.; Mitchell, Richard; Moreno, Heitor; Kwong, Raymond; Jerosch?Herold, Michael

2014-01-01

217

ASSESSMENT OF MATHEMATICAL MODELS FOR STORM AND COMBINED SEWER MANAGEMENT. APPENDIX F: SELECTED COMPUTER INPUT AND OUTPUT  

EPA Science Inventory

Mathematical models for the nonsteady simulation of urban runoff were evaluated to determine their suitability for the engineering assessment, planning, design and control of storm and combined sewerage systems. The models were evaluated on the basis of information published by t...

218

Statistical downscaling and bias correction of climate model outputs for climate change impact assessment in the U.S. northeast  

E-print Network

, and sometimes irreversible, shift in the long-term statistics of climate variables in a specific region of researchers and stakeholders. All impact assessments require climate data at various spatial and temporal scales. Observed daily climate data, usually at sufficiently fine resolution, are available to perform

Silander Jr., John A.

219

Assessment of cardiac ischaemia and viability: role of cardiovascular magnetic resonance  

PubMed Central

Over the past years, cardiovascular magnetic resonance (CMR) has proven its efficacy in large clinical trials, and consequently, the assessment of function, viability, and ischaemia by CMR is now an integrated part of the diagnostic armamentarium in cardiology. By combining these CMR applications, coronary artery disease (CAD) can be detected in its early stages and this allows for interventions with the goal to reduce complications of CAD such as infarcts and subsequently chronic heart failure (CHF). As the CMR examinations are robust and reproducible and do not expose patients to radiation, they are ideally suited for repetitive studies without harm to the patients. Since CAD is a chronic disease, the option to monitor CAD regularly by CMR over many decades is highly valuable. Cardiovascular magnetic resonance also progressed recently in the setting of acute coronary syndromes. In this situation, CMR allows for important differential diagnoses. Cardiovascular magnetic resonance also delineates precisely the different tissue components in acute myocardial infarction such as necrosis, microvascular obstruction (MVO), haemorrhage, and oedema, i.e. area at risk. With these features, CMR might also become the preferred tool to investigate novel treatment strategies in clinical research. Finally, in CHF patients, the versatility of CMR to assess function, flow, perfusion, and viability and to characterize tissue is helpful to narrow the differential diagnosis and to monitor treatment. PMID:21398645

Schwitter, Juerg; Arai, Andrew E.

2011-01-01

220

Assessing Cardiac Injury in Mice with Dual Energy-microCT, 4D-microCT and microSPECT Imaging Following Partial-Heart Irradiation  

PubMed Central

Purpose To develop a mouse model of cardiac injury following partial-heart irradiation (PHI) and test whether DE-microCT and 4D-microCT can be used to assess cardiac injury after PHI to complement myocardial perfusion imaging using microSPECT. Methods and Materials To study cardiac injury from tangent field irradiation in mice, we used a small-field biological irradiator to deliver a single dose of 12 Gy x-rays to approximately one-third of the left ventricle (LV) of Tie2Cre; p53FL/+ and Tie2Cre; p53FL/? mice, where one or both alleles of p53 are deleted in endothelial cells. Four and 8 weeks after irradiation, mice were injected with gold and iodinated nanoparticle-based contrast agents, and imaged with DE-microCT and 4D-microCT to evaluate myocardial vascular permeability and cardiac function, respectively. Additionally, the same mice were imaged with microSPECT to assess myocardial perfusion. Results After PHI with tangent fields, DE-microCT scans showed a time-dependent increase in accumulation of gold nanoparticles (AuNp) in the myocardium of Tie2Cre; p53FL/? mice. In Tie2Cre; p53FL/? mice, extravasation of AuNp was observed within the irradiated LV, whereas in the myocardium of Tie2Cre; p53FL/+ mice, AuNp were restricted to blood vessels. In addition, data from DE-microCT and microSPECT showed a linear correlation (R2=0.97) between the fraction of the LV that accumulated AuNp and the fraction of LV with a perfusion defect. Furthermore, 4D-microCT scans demonstrated that PHI caused Tie2Cre; p53FL/? mice to develop a markedly decreased ejection fraction, and higher end-diastolic and end-systolic volumes, which were associated with compensatory cardiac hypertrophy of the heart that was not irradiated. Conclusions Our results show that DE-microCT and 4D-microCT with nanoparticle-based contrast agents are novel imaging approaches complementary to microSPECT to non-invasively assess the change in myocardial vascular permeability and cardiac function of mice that develop myocardial injury after PHI. PMID:24521682

Lee, Chang-Lung; Min, Hooney; Befera, Nicholas; Clark, Darin; Qi, Yi; Das, Shiva; Johnson, G. Allan; Badea, Cristian T.; Kirsch, David G.

2014-01-01

221

Remote detection of mental workload changes using cardiac parameters assessed with a low-cost webcam.  

PubMed

We introduce a new framework for detecting mental workload changes using video frames obtained from a low-cost webcam. Image processing in addition to a continuous wavelet transform filtering method were developed and applied to remove major artifacts and trends on raw webcam photoplethysmographic signals. The measurements are performed on human faces. To induce stress, we have employed a computerized and interactive Stroop color word test on a set composed by twelve participants. The electrodermal activity of the participants was recorded and compared to the mental workload curve assessed by merging two parameters derived from the pulse rate variability and photoplethysmographic amplitude fluctuations, which reflect peripheral vasoconstriction changes. The results exhibit strong correlation between the two measurement techniques. This study offers further support for the applicability of mental workload detection by remote and low-cost means, providing an alternative to conventional contact techniques. PMID:25150821

Bousefsaf, Frédéric; Maaoui, Choubeila; Pruski, Alain

2014-10-01

222

Intractable chest pain in cardiomyopathy: treatment by a novel technique of cardiac cryodenervation with quantitative immunohistochemical assessment of success.  

PubMed

A novel method of cardiac denervation by cryoablation has been developed experimentally. The technique uses liquid nitrogen delivered under pressure to ablate the principal sources of cardiac innervation--namely, the adventitia surrounding the aorta, pulmonary arteries, and veins. The technique has been verified experimentally both in vivo by physiological means and in vitro by quantitative immunohistochemistry and the measurement of myocardial noradrenaline concentrations. A 35 year old woman presented with intractable precordial pain, normal epicardial coronary arteries, and hypertrophic cardiomyopathy. Her symptoms were refractory to maximal medical treatment and she was thought to be unsuitable for either conventional myocardial revascularisation, autotransplantation, or allografting with the concomitant risk of transplant coronary artery disease. She therefore underwent cardiac denervation by the method developed in the laboratory. There was quantitative immunohistochemical evidence of extrinsic cardiac denervation associated with a considerable improvement in her symptoms. This improvement persisted during a follow up period of over 16 months. PMID:8280529

Gaer, J A; Gordon, L; Wharton, J; Polak, J M; Taylor, K M; McKenna, W; Parker, D J

1993-12-01

223

7 Tesla (T) human cardiovascular magnetic resonance imaging using FLASH and SSFP to assess cardiac function: validation against 1.5 T and 3 T  

PubMed Central

We report the first comparison of cardiovascular magnetic resonance imaging (CMR) at 1.5 T, 3 T and 7 T field strengths using steady state free precession (SSFP) and fast low angle shot (FLASH) cine sequences. Cardiac volumes and mass measurements were assessed for feasibility, reproducibility and validity at each given field strength using FLASH and SSFP sequences. Ten healthy volunteers underwent retrospectively electrocardiogram (ECG) gated CMR at 1.5 T, 3 T and 7 T using FLASH and SSFP sequences. B1 and B0 shimming and frequency scouts were used to optimise image quality. Cardiac volume and mass measurements were not significantly affected by field strength when using the same imaging sequence (P > 0.05 for all parameters at 1.5 T, 3 T and 7 T). SSFP imaging returned larger end diastolic and end systolic volumes and smaller left ventricular masses than FLASH imaging at 7 T, and at the lower field strengths (P < 0.05 for each parameter). However, univariate general linear model analysis with fixed effects for sequence and field strengths found an interaction between imaging sequence and field strength (P = 0.03), with a smaller difference in volumes and mass measurements between SSFP and FLASH imaging at 7 T than 1.5 T and 3 T. SSFP and FLASH cine imaging at 7 T is technically feasible and provides valid assessment of cardiac volumes and mass compared with CMR imaging at 1.5 T and 3 T field strengths. PMID:21774009

Suttie, J. J.; DelaBarre, L.; Pitcher, A.; van de Moortele, P. F.; Dass, S.; Snyder, C. J.; Francis, J. M.; Metzger, G. J.; Weale, P.; Ugurbil, K.; Neubauer, S.; Robson, M.; Vaughan, T.

2012-01-01

224

Assessment of new immunosuppressive drugs in a rat cardiac allograft heterotopic model.  

PubMed

We assessed FK506 (FK) and rapamycin (RPM) in a heterotopic abdominal rat heart transplant model using a major histocompatibility mismatch (DA to LEW). The end point of our study was histologic grading of rejection (Billingham and working formulation) at 1 week. Two doses of FK (2.0 and 8.0 mg/kg p.o., q.d.) and RPM (1.5 and 6.0 mg/kg i.p., q.d.) were compared to allografts without and with ciclosporin (12.5 mg/kg p.o., q.d.) treatment. Results show: (1) weak heartbeat and full rejection on day 5 in all untreated allografts; (2) weak heartbeat and high degree of rejection in groups receiving low doses of FK and RPM; (3) strong heartbeat and mild rejection in both high FK and RPM dose groups comparable to the results of the hearts treated with ciclosporin; (4) 1 animal in each high FK and RPM dose group showed possible signs of toxicity, and (5) the strength of the heartbeat was not a reliable indicator of the efficacy of an immunosuppressive drug. We conclude that even in a major histocompatibility mismatch model at the time of the strongest immune response (1 week), all three tested drugs can reduce the degree of rejection from severe (untreated allografts) to mild if given in an adequate dosage. PMID:1380460

Walpoth, B; Galdikas, J; Vorburger, T; Altermatt, H J; Schaffner, T; Althaus, U; Billingham, M; Morris, R

1992-01-01

225

Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging  

SciTech Connect

Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI{sub 100} as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI{sub 100} is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, {sigma}. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI{sub 100} calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good agreement between the measured dose profile data and the fitted Gaussian functions. The solid-state detector had no energy dependence--within the energy range of interest--and the analytical model succeeded in reproducing the absolute dose values obtained with the pencil ion chamber. For the case of large cone-beam single axial scans, the quantity that better characterizes the total energy imparted to the patient is the weighted dose profile integral (DPI{sub w}). The DPI{sub w} can be easily determined from the two parameters that define the Gaussian functions: f(0) and {sigma}. The authors found that the DLP underestimated the total energy imparted to the patient by more than 20%. The authors also found that the calculated CT dosimetric quantities were higher than those displayed on the scanner console. Conclusions: The authors described and validated a method to assess radiation dose in large cone-beam single axial scans. This method offers a simple and more accurate estimation of the total energy imparted to the patient, thus offering the possibility to update the bridge between CT dosimetry and the estimation of the effective dose for cone-beam CT examinations in radiology, nuclear medicine, and radiation therapy.

Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat [Servei de Radiofisica i Radioproteccio, Hospital de la Santa Creu i Sant Pau, Sant Antoni Maria Claret 167, 08025 Barcelona (Spain)

2011-03-15

226

Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile  

SciTech Connect

The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Na{sub v}1.5 sodium and Ca{sub v}1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (? 10 ?M) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. - Highlights: • We study effects of anti-addiction drug ibogaine on ionic currents in cardiomyocytes. • We assess the cardiac ion channel profile of ibogaine. • Ibogaine inhibits hERG potassium, sodium and calcium channels. • Ibogaine’s effects on ion channels are a potential source of cardiac arrhythmias. • 18-Methoxycoronaridine has a lower affinity for cardiac ion channels than ibogaine.

Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Hilber, Karlheinz, E-mail: karlheinz.hilber@meduniwien.ac.at [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Sandtner, Walter [Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, 1090 Vienna (Austria)

2013-12-01

227

Exceptional CO? tolerance in white sturgeon (Acipenser transmontanus) is associated with protection of maximum cardiac performance during hypercapnia in situ.  

PubMed

White sturgeon rank among the most CO?-tolerant fish species examined to date. We investigated whether this exceptional CO? tolerance extended to the heart, an organ generally viewed as acidosis intolerant. Maximum cardiac output (Q(max)) and maximum cardiac power output (PO(max)) were assessed using a working, perfused, in situ heart preparation. Exposure to a Pco? of 3 kPa for 20 min had no significant effect on maximum cardiac performance, while exposure to 6-kPa Pco? reduced heart rate, Q(max), PO(max), and rate of ventricular force generation (F(O)) by 23%, 28%, 26%, and 18%, respectively; however, full recovery was observed in all these parameters upon return to control conditions. These modest impairments during exposure to 6-kPa Pco? were associated with partially compensated intracellular ventricular acidosis. Maximum adrenergic stimulation (500 nmol L?¹ adrenaline) during 6-kPa Pco? protected maximum cardiac performance via increased inotropy (force of contraction) without affecting heart rate. Exposure to higher CO? levels associated with morbidity in vivo (i.e., 8-kPa Pco?) induced arrhythmia and a reduction in stroke volume during power assessment. Clearly, white sturgeon hearts are able to increase cardiac performance during severe hypercapnia that is lethal to other fishes. Future work focusing on atypical aspects of sturgeon cardiac function, including the lack of chronotropic response to adrenergic stimulation during hypercapnia, is warranted. PMID:21527814

Baker, Daniel W; Hanson, Linda M; Farrell, Anthony P; Brauner, Colin J

2011-01-01

228

Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom  

NASA Astrophysics Data System (ADS)

State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

Budde, Adam; Nilsen, Roy; Nett, Brian

2014-03-01

229

Necessity of angiotensin-converting enzyme-related gene for cardiac functions and longevity of Drosophila melanogaster assessed by optical coherence tomography  

NASA Astrophysics Data System (ADS)

Prior studies have established the necessity of an angiotensin-converting enzyme-related (ACER) gene for heart morphogenesis of Drosophila. Nevertheless, the physiology of ACER has yet to be comprehensively understood. Herein, we employed RNA interference to down-regulate the expression of ACER in Drosophila's heart and swept source optical coherence tomography to assess whether ACER is required for cardiac functions in living adult flies. Several contractile parameters of Drosophila heart, including the heart rate (HR), end-diastolic diameter (EDD), end-systolic diameter (ESD), percent fractional shortening (%FS), and stress-induced cardiac performance, are shown, which are age dependent. These age-dependent cardiac functions declined significantly when ACER was down-regulated. Moreover, the lifespans of ACER knock-down flies were significantly shorter than those of wild-type control flies. Thus, we posit that ACER, the Drosophila ortholog of mammalian angiotensin-converting enzyme 2 (ACE2), is essential for both heart physiology and longevity of animals. Since mammalian ACE2 controls many cardiovascular physiological features and is implicated in cardiomyopathies, our findings that ACER plays conserved roles in genetically tractable animals will pave the way for uncovering the genetic pathway that controls the renin-angiotensin system.

Liao, Fang-Tsu; Chang, Cheng-Yi; Su, Ming-Tsan; Kuo, Wen-Chuan

2014-01-01

230

Cardiac Resynchronization Therapy Upregulates Cardiac Autonomic Control  

PubMed Central

Objective: To determine the effect of cardiac resynchronization therapy (CRT) on sympathetic nervous function in heart failure (HF). Background: Neurohormonal dysregulation and cardiac autonomic dysfunction are associated with HF and contribute to HF progression and its poor prognosis. We hypothesized that mechanical resynchronization improves cardiac sympathetic function in HF. Methods: Sixteen consecutive patients receiving CRT for advanced cardiomyopathy and 10 controls were included in this prospective study. NYHA class, 6-minute walk distance, echocardiographic parameters, plasma norepinephrine (NE) were assessed at baseline, 3-month and 6-month follow-up. Cardiac sympathetic function was determined by 123iodine metaiodobenzylguanidine (123I-MIBG) scintigraphy and 24-hour ambulatory electrocardiography. Results: Along with improvement in NYHA class (3.1 ± 0.3 to 2.1 ± 0.4, P < 0.001) and LVEF (23 ± 6% to 33 ± 12%, P < 0.001 delayed heart/mediastinum (H/M) 123 I-MIBG ratio increased significantly (1.8 ± 0.7 to 2.1 ± 0.6, P = 0.04) while the H/M 123I-MIBG washout rate decreased significantly (54 ± 25% to 34± 24%, P = 0.01) from baseline to 6-month follow-up. The heart rate variability (HRV) measured in SD of normal-to-normal intervals also increased significantly from baseline (82 ± 30 ms) to follow-up (111 ± 32 ms, P = 0.04). The improvement in NYHA after CRT was significantly associated with baseline 123I-MIBG H/M washout rate (r = 0.65, P = 0.03). The improvement in LVESV index was associated with baseline 123I-MIBG delayed H/M ratio (r = ?0.67, P = 0.02) and H/M washout rate (r = 0.65, P = 0.03). Conclusion: After CRT, improvements in cardiac symptoms and LV function were accompanied by rebalanced cardiac autonomic control as measured by 123I-MIBG and HRV. PMID:18479331

CHA, YONG-MEI; OH, JAE; MIYAZAKI, CHINAMI; HAYES, DAVID L.; REA, ROBERT F.; SHEN, WIN-KUANG; ASIRVATHAM, SAMUEL J.; KEMP, BRAD J.; HODGE, DAVID O.; CHEN, PENG-SHENG; CHAREONTHAITAWEE, PANITHAYA

2009-01-01

231

Databases for assessing the outcomes of the treatment of patients with congenital and paediatric cardiac disease--the perspective of cardiology.  

PubMed

This review includes a brief discussion, from the perspective of the pediatric cardiologist, of the rationale for creation and maintenance of multi-institutional databases of outcomes of the treatment of patients with congenital and paediatric cardiac disease, together with a history of the evolution of such databases, and a description of the current state of the art. A number of projects designed to have broad-based impact are currently in the design phase, or have already been implemented. Not surprisingly, most of the efforts thus far have focused on catheterization procedures and interventions, although some work examining other aspects of paediatric cardiology practice is also beginning. This review briefly describes several European and North American initiatives related to databases for pediatric and congenital cardiology including the Central Cardiac Audit Database of the United Kingdom, national database initiatives for pediatric cardiology in Switzerland and Germany, various database initiatives under the leadership of the Working Groups of The Association for European Paediatric Cardiology, the IMPACT Registry (IMproving Pediatric and Adult Congenital Treatment) of the National Cardiovascular Data Registry of The American College of Cardiology Foundation and The Society for Cardiovascular Angiography and Interventions (SCAI), the Mid-Atlantic Group of Interventional Cardiology (MAGIC) Catheterization Outcomes Project, the Congenital Cardiac Catheterization Project on Outcomes (C3PO), the Congenital Cardiovascular Interventional Study Consortium (CCISC), and the Joint Council on Congenital Heart Disease (JCCHD) National Quality Improvement Initiative. These projects, each leveraging multicentre data and collaboration, demonstrate the enormous progress that has occurred over the last several years to improve the quality and consistency of information about nonsurgical treatment for congenital cardiac disease. The paediatric cardiology field is well-poised to move quickly beyond outcome assessment and benchmarking, to collaborative quality improvement. PMID:19063781

Jenkins, Kathy J; Beekman Iii, Robert H; Bergersen, Lisa J; Everett, Allen D; Forbes, Thomas J; Franklin, Rodney C G; Klitzner, Thomas S; Krogman, Otto N; Martin, Gerard R; Webb, Catherine L

2008-12-01

232

Utility of Doppler Myocardial Imaging, Cardiac Biomarkers and Clonal Immunoglobulin Genes to Assess Left Ventricular Performance and Stratify Risk Following Peripheral Blood Stem Cell Transplantation in Patients with Systemic Light Chain Amyloidosis (AL)  

PubMed Central

Cardiac dysfunction is a well-recognized complication of light chain amyloidosis (AL). Autologous stem cell transplant (auto-SCT) has emerged as a successful treatment modality for AL patients. In this study, we examined the effect of clonal immunoglobulin light chain genes (VL), which encodes the immunoglobulin light chain protein that ultimately forms amyloid, on cardiac function, in the context of auto-SCT and its impact on overall survival. Longitudinal Doppler myocardial imaging parameters along with cardiac biomarkers were used to assess for cardiac function pre and post auto-SCT. VL gene analysis revealed that V? genes, in particular V?VI, were associated with worse cardiac function parameters than V? genes. Clonal VL genes appeared to have an impact on left ventricular (LV) function post-transplant and also influenced mortality, with specific VL gene families associated with lower survival. Another key predictor of mortality in this report was change in tricuspid regurgitant flow velocity following auto-SCT. Correlations were also observed between systolic strain rate, systolic strain and VL genes associated with amyloid formation. In summary, clonal VL gene usage influences global cardiac function in AL, with patients having V?VI and V?II-III-associated amyloid more severely affected than those having V? or V?I amyloid. Pulsed wave tissue Doppler imaging along with immunoglobulin gene analysis offers novel insights into prediction of mortality and cardiac dysfunction in AL after auto-SCT. PMID:21315556

Bellavia, Diego; Abraham, Roshini S.; Pellikka, Patricia A.; Dispenzieri, Angela; Burnett, John C.; Al-Zahrani, Ghormallah B.; Green, Tammy D.; Manske, Michelle K.; Gertz, Morie A.; Miller, Fletcher A.; Abraham, Theodore P.

2011-01-01

233

Cardiac Arrest  

MedlinePLUS

... or it can stop beating. Sudden cardiac arrest (SCA) occurs when the heart develops an arrhythmia that ... is blocked. There are many possible causes of SCA. They include coronary heart disease, physical stress, and ...

234

Cardiac Paragangliomas.  

PubMed

Cardiac paraganglioma is a rare entity. We review the clinical data from 158 patients reported in 132 isolated papers, and discuss clinical presentations, imaging findings, pathology, location, therapy, and outcomes. PMID:25331372

Wang, Ji-Gang; Han, Jing; Jiang, Tao; Li, Yu-Jun

2014-10-20

235

Cardiac Catheterization  

MedlinePLUS

... done during a cardiac catheterization include: closing small holes inside the heart repairing leaky or narrow heart ... bandage. It's normal for the site to be black and blue, red, or slightly swollen for a ...

236

Comparisons of four categories of waste recycling in China's paper industry based on physical input-output life-cycle assessment model  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Using crop straws and wood wastes for paper production should be promoted. Black-Right-Pointing-Pointer Bagasse and textile waste recycling should be properly limited. Black-Right-Pointing-Pointer Imports of scrap paper should be encouraged. Black-Right-Pointing-Pointer Sensitivity analysis, uncertainties and policy implications are discussed. - Abstract: Waste recycling for paper production is an important component of waste management. This study constructs a physical input-output life-cycle assessment (PIO-LCA) model. The PIO-LCA model is used to investigate environmental impacts of four categories of waste recycling in China's paper industry: crop straws, bagasse, textile wastes and scrap paper. Crop straw recycling and wood utilization for paper production have small total intensity of environmental impacts. Moreover, environmental impacts reduction of crop straw recycling and wood utilization benefits the most from technology development. Thus, using crop straws and wood (including wood wastes) for paper production should be promoted. Technology development has small effects on environmental impacts reduction of bagasse recycling, textile waste recycling and scrap paper recycling. In addition, bagasse recycling and textile waste recycling have big total intensity of environmental impacts. Thus, the development of bagasse recycling and textile waste recycling should be properly limited. Other pathways for reusing bagasse and textile wastes should be explored and evaluated. Moreover, imports of scrap paper should be encouraged to reduce large indirect impacts of scrap paper recycling on domestic environment.

Liang Sai [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); Zhang, Tianzhu, E-mail: zhangtz@mail.tsinghua.edu.cn [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); Xu Yijian [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); China Academy of Urban Planning and Design, Beijing 100037 (China)

2012-03-15

237

Epo deficiency alters cardiac adaptation to chronic hypoxia.  

PubMed

The involvement of erythropoietin in cardiac adaptation to acute and chronic (CHx) hypoxia was investigated in erythropoietin deficient transgenic (Epo-TAg(h)) and wild-type (WT) mice. Left (LV) and right ventricular functions were assessed by echocardiography and hemodynamics. HIF-1?, VEGF and Epo pathways were explored through RT-PCR, ELISA, Western blot and immunocytochemistry. Epo gene and protein were expressed in cardiomyocytes of WT mice in normoxia and hypoxia. Increase in blood hemoglobin, angiogenesis and functional cardiac adaptation occurred in CHx in WT mice, allowing a normal oxygen delivery (O2T). Epo deficiency induced LV hypertrophy, increased cardiac output (CO) and angiogenesis, but O2T remained lower than in WT mice. In CHx Epo-TAg(h) mice, LV hypertrophy, CO and O2T decreased. HIF-1? and Epo receptor pathways were depressed, suggesting that Epo-TAg(h) mice could not adapt to CHx despite activation of cardioprotective pathways (increased P-STAT-5/STAT-5). HIF/Epo pathway is activated in the heart of WT mice in hypoxia. Chronic hypoxia induced cardiac adaptive responses that were altered with Epo deficiency, failing to maintain oxygen delivery to tissues. PMID:23333855

El Hasnaoui-Saadani, Raja; Marchant, Dominique; Pichon, Aurélien; Escoubet, Brigitte; Pezet, Mylène; Hilfiker-Kleiner, Denise; Hoch, Melanie; Pham, Isabelle; Quidu, Patricia; Voituron, Nicolas; Journé, Clément; Richalet, Jean-Paul; Favret, Fabrice

2013-04-01

238

Cardiac factors in orthostatic hypotension  

NASA Astrophysics Data System (ADS)

Cardiac function is determined by preload, afterload, heart rate and contractility. During orthostatic stress, the footward blood shift is compensated for by an increase of afterload. LBNP is widely used to analyze effects of volume displacement during orthostatic stress. Comparisons of invasive ( right heart catheterization) and non-invasive approach (echocardiography) yielded similar changes. Preload and afterload change with graded LBNP, heart rate increases, and stroke volume and cardiac output decrease. Thus, the working point on the left ventricular function curve is shifted to the left and downward, similar to hypovolemia. However, position on the Frank-Starling curve, the unchanged ejection fraction, and the constant Vcf indicate a normal contractile state during LBNP. A decrease of arterial oxygen partial pressure during LBNP shwos impaired ventilation/perfusion ratio. Finally, LBNP induced cardiac and hemodynamic changes can be effectively countermeasured by dihydroergotamine, a potent venoconstrictor. Comparison of floating catheter data with that of echocardiography resulted in close correlation for cardiac output and stroke volume. In addition, cardiac dimensions changed in a similar way during LBNP. From our findings, echocardiography as a non-invasive procedure can reliably used in LBNP and orthostatic stress tests. Some informations can be obtained on borderline values indicating collaps or orthostatic syncope. Early fainters can be differentiated from late fainters by stroke volume changes.

Löllgen, H.; Dirschedl, P.; Koppenhagen, K.; Klein, K. E.

239

d-Propranolol protects against oxidative stress and progressive cardiac dysfunction in iron overloaded rats  

PubMed Central

d-Propranolol (d-Pro: 2–8 mg·(kg body mass)?1·day?1) protected against cardiac dysfunction and oxidative stress during 3–5 weeks of iron overload (2 mg Fe–dextran·(g body mass)?1·week?1) in Sprague–Dawley rats. At 3 weeks, hearts were perfused in working mode to obtain baseline function; red blood cell glutathione, plasma 8-isoprostane, neutrophil basal superoxide production, lysosomal-derived plasma N-acetyl-?-galactosaminidase (NAGA) activity, ventricular iron content, and cardiac iron deposition were assessed. Hearts from the Fe-treated group of rats exhibited lower cardiac work (26%) and output (CO, 24%); end-diastolic pressure rose 1.8-fold. Further, glutathione levels increased 2-fold, isoprostane levels increased 2.5-fold, neutrophil superoxide increased 3-fold, NAGA increased 4-fold, ventricular Fe increased 4.9-fold; and substantial atrial and ventricular Fe-deposition occurred. d-Pro (8 mg) restored heart function to the control levels, protected against oxidative stress, and decreased cardiac Fe levels. After 5 weeks of Fe treatment, echocardiography revealed that the following were depressed: percent fractional shortening (%FS, 31% lower); left ventricular (LV) ejection fraction (LVEF, 17%), CO (25%); and aortic pressure maximum (Pmax, 24%). Mitral valve E/A declined by 18%, indicating diastolic dysfunction. Cardiac CD11b+ infiltrates were elevated. Low d-Pro (2 mg) provided modest protection, whereas 4–8 mg greatly improved LVEF (54%–75%), %FS (51%–81%), CO (43%–78%), Pmax (56%–100%), and E/A >100%; 8 mg decreased cardiac inflammation. Since d-Pro is an antioxidant and reduces cardiac Fe uptake as well as inflammation, these properties may preserve cardiac function during Fe overload. PMID:22913465

Kramer, Jay H.; Spurney, Christopher F.; Iantorno, Micaela; Tziros, Constantine; Chmielinska, Joanna J.; Mak, I. Tong; Weglicki, William B.

2013-01-01

240

Gated F-18 FDG PET for Assessment of Left Ventricular Volumes and Ejection Fraction Using QGS and 4D-MSPECT in Patients with Heart Failure: A Comparison with Cardiac MRI  

PubMed Central

Purpose Ventricular function is a powerful predictor of survival in patients with heart failure (HF). However, studies characterizing gated F-18 FDG PET for the assessment of the cardiac function are rare. The aim of this study was to prospectively compare gated F-18 FDG PET and cardiac MRI for the assessment of ventricular volume and ejection fraction (EF) in patients with HF. Methods Eighty-nine patients with diagnosed HF who underwent both gated F-18 FDG PET/CT and cardiac MRI within 3 days were included in the analysis. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), and EF were obtained from gated F-18 FDG PET/CT using the Quantitative Gated SPECT (QGS) and 4D-MSPECT software. Results LV EDV and LV ESV measured by QGS were significantly lower than those measured by cardiac MRI (both P<0.0001). In contrast, the corresponding values for LV EDV for 4D-MSPECT were comparable, and LV ESV was underestimated with borderline significance compared with cardiac MRI (P?=?0.047). LV EF measured by QGS and cardiac MRI showed no significant differences, whereas the corresponding values for 4D-MSPECT were lower than for cardiac MRI (P<0.0001). The correlations of LV EDV, LV ESV, and LV EF between gated F-18 FDG PET/CT and cardiac MRI were excellent for both QGS (r?=?0.92, 0.92, and 0.76, respectively) and 4D-MSPECT (r?=?0.93, 0.94, and 0.75, respectively). However, Bland-Altman analysis revealed a significant systemic error, where LV EDV (?27.9±37.0 mL) and ESV (?18.6±33.8 mL) were underestimated by QGS. Conclusion Despite the observation that gated F-18 FDG PET/CT were well correlated with cardiac MRI for assessing LV function, variation was observed between the two imaging modalities, and so these imaging techniques should not be used interchangeably. PMID:24404123

Zhao, Shi-Hua; He, Zuo-Xiang; Wang, Dao-Yu; Guo, Feng; Fang, Wei; Yang, Min-Fu

2014-01-01

241

Value of baseline left lateral wall postsystolic displacement assessed by M-mode to predict reverse remodeling by cardiac resynchronization therapy.  

PubMed

Although left ventricular (LV) dyssynchrony assessed by ultrasound is emerging as superior to QRS duration in predicting response to cardiac resynchronization therapy (CRT), the role of conventional echocardiographic parameters of dyssynchrony is still debated. Forty-eight patients with heart failure in New York Heart Association classes III to IV, LV ejection fraction < or =35%, and QRS duration > or =120 ms were studied. LV dyssynchrony was evaluated by M-mode as septal-to-posterior wall motion delay and left lateral wall postsystolic displacement (LWPSD). Interventricular dyssynchrony was defined as the difference between the LV and right ventricular preejection periods measured by standard Doppler. Reverse remodeling was defined as an LV end-systolic volume decrease > or =15% after 6 months of CRT. Thirty-one patients (65%) were considered responders to CRT. At baseline responders differed from nonresponders by having less severe New York Heart Association class (p = 0.006), lower percentage of ischemic cause (p = 0.006), longer PR interval (p = 0.013), shorter LV diastolic filling time corrected for heart rate (p = 0.005), and presence of LWPSD (p = 0.003). At multivariate analysis, predictors of CRT response were LWPSD (odds ratio [OR] 1.045, 95% confidence interval [CI] 1.001 to 1.091; p = 0.043), LV diastolic filling time corrected for heart rate (OR 0.855, 95% CI 0.744 to 0.981, p = 0.026), and nonischemic cause (OR 0.109, 95% CI 0.018 to 0.657, p = 0.016). In conclusion, preimplantation assessment of cardiac dyssynchrony based on M-mode LWPSD may predict LV reverse remodeling after CRT, especially in patients with nonischemic cause and shorter diastolic filling time. This suggests the potential role of baseline postsystolic mechanical phenomena in determining response to CRT independently of QRS duration. PMID:17659931

Sassone, Biagio; Capecchi, Alessandro; Boggian, Giulio; Gabrieli, Luca; Saccà, Saverio; Vandelli, Roberto; Petracci, Elisabetta; Mele, Donato

2007-08-01

242

Cardiac mechanics: Physiological, clinical, and mathematical considerations  

NASA Technical Reports Server (NTRS)

Recent studies concerning the basic physiological and biochemical principles underlying cardiac muscle contraction, methods for the assessment of cardiac function in the clinical situation, and mathematical approaches to cardiac mechanics are presented. Some of the topics covered include: cardiac ultrastructure and function in the normal and failing heart, myocardial energetics, clinical applications of angiocardiography, use of echocardiography for evaluating cardiac performance, systolic time intervals in the noninvasive assessment of left ventricular performance in man, evaluation of passive elastic stiffness for the left ventricle and isolated heart muscle, a conceptual model of myocardial infarction and cardiogenic shock, application of Huxley's sliding-filament theory to the mechanics of normal and hypertrophied cardiac muscle, and a rheological modeling of the intact left ventricle. Individual items are announced in this issue.

Mirsky, I. (editor); Ghista, D. N.; Sandler, H.

1974-01-01

243

Partial scan artifact reduction (PSAR) for the assessment of cardiac perfusion in dynamic phase-correlated CT  

SciTech Connect

Purpose: Cardiac CT achieves its high temporal resolution by lowering the scan range from 2{pi} to {pi} plus fan angle (partial scan). This, however, introduces CT-value variations, depending on the angular position of the {pi} range. These partial scan artifacts are of the order of a few HU and prevent the quantitative evaluation of perfusion measurements. The authors present the new algorithm partial scan artifact reduction (PSAR) that corrects a dynamic phase-correlated scan without a priori information. Methods: In general, a full scan does not suffer from partial scan artifacts since all projections in [0, 2{pi}] contribute to the data. To maintain the optimum temporal resolution and the phase correlation, PSAR creates an artificial full scan p{sub n}{sup AF} by projectionwise averaging a set of neighboring partial scans p{sub n}{sup P} from the same perfusion examination (typically N{approx_equal}30 phase-correlated partial scans distributed over 20 s and n=1,...,N). Corresponding to the angular range of each partial scan, the authors extract virtual partial scans p{sub n}{sup V} from the artificial full scan p{sub n}{sup AF}. A standard reconstruction yields the corresponding images f{sub n}{sup P}, f{sub n}{sup AF}, and f{sub n}{sup V}. Subtracting the virtual partial scan image f{sub n}{sup V} from the artificial full scan image f{sub n}{sup AF} yields an artifact image that can be used to correct the original partial scan image: f{sub n}{sup C}=f{sub n}{sup P}-f{sub n}{sup V}+f{sub n}{sup AF}, where f{sub n}{sup C} is the corrected image. Results: The authors evaluated the effects of scattered radiation on the partial scan artifacts using simulated and measured water phantoms and found a strong correlation. The PSAR algorithm has been validated with a simulated semianthropomorphic heart phantom and with measurements of a dynamic biological perfusion phantom. For the stationary phantoms, real full scans have been performed to provide theoretical reference values. The improvement in the root mean square errors between the full and the partial scans with respect to the errors between the full and the corrected scans is up to 54% for the simulations and 90% for the measurements. Conclusions: The phase-correlated data now appear accurate enough for a quantitative analysis of cardiac perfusion.

Stenner, Philip; Schmidt, Bernhard; Bruder, Herbert; Allmendinger, Thomas; Haberland, Ulrike; Flohr, Thomas; Kachelriess, Marc [Institute of Medical Physics, Henkestrasse 91, 91052 Erlangen (Germany); Siemens AG, Healthcare Sector, Siemensstrasse 1, 91301 Forchheim (Germany); Institute of Medical Physics, Henkestrasse. 91, 91052 Erlangen (Germany)

2009-12-15

244

Effects of exercise rehabilitation on cardiac electrical instability assessed by T-wave alternans during ambulatory electrocardiogram monitoring in coronary artery disease patients without and with diabetes mellitus.  

PubMed

Effects of exercise rehabilitation on electrocardiographic markers of risk for sudden cardiac death have not been adequately studied. We examined effects of controlled exercise training on T-wave alternans (TWA) in 24-hour ambulatory electrocardiogram recordings in patients with stable coronary artery disease (CAD) without and with type 2 diabetes mellitus (DM). Consecutive patients with angiographically confirmed CAD were recruited to join the ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) study. Exercise (n = 65) and control groups (n = 65) were matched on age, sex, DM, and previous myocardial infarction. Ambulatory electrocardiograms were recorded before and after a 2-year training period. TWA was assessed using time domain-modified moving average method by an investigator blinded to patients' clinical status. Average TWA values decreased in the rehabilitation group but not in control patients (rehabilitation [mean ± SEM]: 52.8 ± 1.7 ?V vs 48.7 ± 1.5 ?V, p <0.001; control: 53.7 ± 1.7 ?V vs 54.3 ± 1.6 ?V, p = 0.746). Changes in TWA differed between the groups (rehabilitation: -4.1 ± 1.2 ?V vs controls: +0.6 ± 1.1 ?V, p = 0.005). In CAD + DM patients, 50% (n = 9) of the 18 positive TWA cases were converted with exercise versus 10% (n = 2 of 20) of controls (p = 0.020). In CAD patients, 30% (n = 8 of 27) of positive TWA cases were converted with exercise versus 4% (n = 1 of 28) of controls (p = 0.012). In conclusion, this is the first report of the effectiveness of exercise rehabilitation to reduce TWA, a marker of sudden cardiac death risk, in patients with stable CAD. PMID:25107578

Kenttä, Tuomas; Tulppo, Mikko P; Nearing, Bruce D; Karjalainen, Jaana J; Hautala, Arto J; Kiviniemi, Antti M; Huikuri, Heikki V; Verrier, Richard L

2014-09-15

245

A Geospatial Assessment of Transport Distance and Survival to Discharge In Out Of Hospital Cardiac Arrest Patients: Implications for Resuscitation Centers  

PubMed Central

OBJECTIVES National leaders have suggested that patients with an out-of-hospital cardiac arrest (OOHCA) may benefit from transport to specialized hospitals. We sought to assess the survival of OOHCA patients by transport distance and hospital proximity. METHODS Prospective, cohort study of OOHCA patients in 11 Resuscitation Outcomes Consortium (ROC) sites across North America. Transport distance and hospital proximity was calculated using weighted centroid of census tract location by Geographic Information Systems (GIS). Patients were stratified into quartiles based on transport distance to the receiving hospital calculated via GIS. Descriptive statistics were used to describe characteristics by transport distance and to compare proximity to other hospitals. Multivariate logistic regression was used to evaluate the impact of transport distance on survival. RESULTS 26,628 patients were identified, 7,540 (28%) were transported by EMS and included in the final analysis. The median transport time was 6.3 minutes (IQR 5.4); the median transport distance being 2.4 miles (3.9 km). Most patients were taken to the closest hospital (71.7%; N=5,412). However, unadjusted survival to discharge was lower for those taken to the closest compared to further hospitals (12.1% vs. 16.5%) despite similar patient characteristics. Transport distance was not associated with survival on logistic analysis (OR 1.00; 95% CI 0.99–1.01). CONCLUSIONS Survival to discharge was higher in OOHCA patients taken to hospitals located further than the closest hospital while transport distance was not associated with survival. This suggests that longer transport distance/time might not adversely affect outcome. Further studies are needed to inform policy decisions regarding best destination post cardiac arrest PMID:20122779

Cudnik, Michael T.; Schmicker, Robert H.; Vaillancourt, Christian; Newgard, Craig D.; Christenson, James M.; Davis, Daniel P.; Lowe, Robert A.

2010-01-01

246

Cardiac sarcoidosis.  

PubMed

The prognosis of sarcoidosis often considered as "benign" is significantly changed in the presence of a cardiac localization. An in-depth interview, a clinical examination together with ECG are often for most of sarcoidosis. Certain conditions (severe multisystemic sarcoidosis, rares localizations in particular neurological, renal, gastric) lead to necessary investigations: Holter ECG, echocardiography, thallium scintigraphy with dipyridamole test, PET scanner and MRI in order to identify infraclinical presentations. Diagnosis relies on guidelines of Japansese criteria, but can benefit from MRI and PET scanner even though their place is not yet clearly defined in clinical pratice. Diagnosing cardiac sarcoidosis means deciding an immunosuppressive treatment. It is highly important to gather all criteria to validate a consistent diagnosis or at least a high probability. In order to best adapt therapy, a coordinated patient care involving the cardiologist and the sarcoidosis specialist is necessary. PMID:22608949

Chapelon-Abric, Catherine

2012-06-01

247

Assessment of the toxicity of hydralazine in the rat using an ultrasensitive flow-based cardiac troponin I immunoassay.  

PubMed

The purpose of this study was to correlate the histologic changes in the heart to serum cardiac troponin I (cTnI) concentrations assayed with the Erenna Immunoassay System in Wistar rats (Crl:Wi[Han]) using the hydralazine model of cardiotoxicity. A single dose of hydralazine caused an increase of cTnI concentrations at six hours post-dose, followed by a sharp decrease at twenty-four hours and a return to baseline at forty-eight hours. The second dose of hydralazine caused a smaller magnitude increase in cTnI concentrations at six hours as compared to the first dose. Also, cTnI concentrations returned to baseline at twenty-four hours after the second dose. The increased cTnI concentrations coincided with acute myocardial necrosis at histology. However, increased cTnI concentrations in the absence of microscopic lesions were identified in several rats. As cTnI concentrations decreased, microscopic changes in the heart matured to cardiomyophagy. In conclusion, the increases in cTnI concentrations six hours after the administration of hydralazine were indicative of a myocardial damage that did not consistently have a microscopic correlate. However, the window of increased cTnI concentrations was short, and only microscopic evaluation of the heart detected the damage at twenty-four to forty-eight hours after the episode of acute myocardial necrosis. PMID:19854888

Mikaelian, Igor; Coluccio, Denise; Hirkaler, Gerard M; Downing, John C; Rasmussen, Erik; Todd, John; Estis, Joel; Lu, Quynh Anh; Nicklaus, Rosemary

2009-12-01

248

Identification and characterization of DM1 patients by a new diagnostic certified assay: neuromuscular and cardiac assessments.  

PubMed

The expansion of the specific trinucleotide sequence, [CTG], is the molecular pathological mechanism responsible for the clinical manifestations of DM1. Many studies have described different molecular genetic techniques to detect DM1, but as yet there is no data on the analytical performances of techniques used so far in this disease. We therefore developed and validated a molecular method, "Myotonic Dystrophy SB kit," to better characterize our DM1 population. 113 patients were examined: 20 DM1-positive, 11 DM1/DM2-negative, and13 DM1-negative/DM2-positive, who had a previous molecular diagnosis, while 69 were new cases. This assay correctly identified 113/113 patients, and all were confirmed by different homemade assays. Comparative analysis revealed that the sensitivity and the specificity of the new kit were very high (>99%). Same results were obtained using several extraction procedures and different concentrations of DNA. The distribution of pathologic alleles showed a prevalence of the "classical" form, while of the 96 nonexpanded alleles 19 different allelic types were observed. Cardiac and neuromuscular parameters were used to clinically characterize our patients and support the new genetic analysis. Our findings suggest that this assay appears to be a very robust and reliable molecular test, showing high reproducibility and giving an unambiguous interpretation of results. PMID:23762868

Valaperta, Rea; Sansone, Valeria; Lombardi, Fortunata; Verdelli, Chiara; Colombo, Alessio; Valisi, Massimiliano; Brigonzi, Elisa; Costa, Elena; Meola, Giovanni

2013-01-01

249

Identification and Characterization of DM1 Patients by a New Diagnostic Certified Assay: Neuromuscular and Cardiac Assessments  

PubMed Central

The expansion of the specific trinucleotide sequence, [CTG], is the molecular pathological mechanism responsible for the clinical manifestations of DM1. Many studies have described different molecular genetic techniques to detect DM1, but as yet there is no data on the analytical performances of techniques used so far in this disease. We therefore developed and validated a molecular method, “Myotonic Dystrophy SB kit,” to better characterize our DM1 population. 113 patients were examined: 20 DM1-positive, 11 DM1/DM2-negative, and13 DM1-negative/DM2-positive, who had a previous molecular diagnosis, while 69 were new cases. This assay correctly identified 113/113 patients, and all were confirmed by different homemade assays. Comparative analysis revealed that the sensitivity and the specificity of the new kit were very high (>99%). Same results were obtained using several extraction procedures and different concentrations of DNA. The distribution of pathologic alleles showed a prevalence of the “classical” form, while of the 96 nonexpanded alleles 19 different allelic types were observed. Cardiac and neuromuscular parameters were used to clinically characterize our patients and support the new genetic analysis. Our findings suggest that this assay appears to be a very robust and reliable molecular test, showing high reproducibility and giving an unambiguous interpretation of results. PMID:23762868

Sansone, Valeria; Lombardi, Fortunata; Verdelli, Chiara; Colombo, Alessio; Brigonzi, Elisa; Costa, Elena; Meola, Giovanni

2013-01-01

250

Cardiac optogenetics  

PubMed Central

Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart. PMID:23457014

2013-01-01

251

Cardiac alterations induced by a fish-catching diving competition.  

PubMed

Cardiac changes induced by repeated breath-hold diving were investigated after a fish-catching diving competition. Eleven healthy subjects carried out repeated breath-hold dives at a mean maximal depth of 20 ± 2.7 msw (66 ± 9 fsw) during 5 h. One hour after the competition, the body mass loss was -1.7 ± 0.5 kg. Most of the breath-hold divers suffered from cold and although the core temperature remained normal, a decrease in cutaneous temperature was recorded in the extremities. Systolic blood pressure was reduced in both upper and lower limbs. Heart rate was unchanged, but left ventricular (LV) stroke volume was reduced leading to a decrease in cardiac output (-20%). Left atrial and LV diameters were significantly decreased. LV filling was assessed on a trans-mitral profile. An increase in the contribution of the atrial contraction to LV filling was observed. Right cavity diameters were increased. The cardiac autonomic alterations were in favor of sympathetic hyperactivity. After a fish-catching diving competition in cold water, alterations suggesting dehydration, contraction in plasma volume and sympathetic hyperactivity were observed. Furthermore, enlargements of right cavities were in favor of right ventricular strains. Repeated apnea and swimming in cold water may account for these alterations. PMID:20738824

Gargne, O; Joulia, F; Golé, Y; Coulange, M; Bessereau, J; Fontanari, P; Desruelle, A-V; Gavarry, O; Boussuges, A

2012-06-01

252

Input-Output Analysis as a Tool in Assessing the Impacts of Climatic Variations on Regional Economies: with Prototype Applications to the Oklahoma Economy.  

NASA Astrophysics Data System (ADS)

Input-output analysis techniques are developed to relate climate impacts affecting specific economic sectors to overall economic impacts in a regional economy. The types of applied problems covered include: (1) Estimates of impacts from "natural" (or historical) climatic variability on the agricultural crop sector and residential consumption; (2) Estimates of likely impacts from an operational weather modification program; (3) Estimates of likely impacts from the implementation of climate-conscious irrigation scheduling strategies; (4) Estimates of likely impacts resulting from climate-conscious residential retrofitting; (5) The feasibility of instituting a statewide water transfer program, including consideration of the impact of scenarios involving climate -conscious irrigation scheduling; (6) A general consideration of using input-output techniques as an "optimal" decision -making tool for regional planners faced with coping with climate-related water shortages. The potentials of input -output analysis for dealing with such problem contexts are explored. Provisional estimates are made of the magnitude of the dollar impacts on the Oklahoma economy. Suggestions are made as how much information can be used to tailor programmatic expenditures to match expected economic gains. Finally, suggestions are made as to promising avenues for future study.

Cooter, William S.

253

Adaptive detection of missed text areas in OCR outputs: application to the automatic assessment of OCR quality in mass digitization projects  

NASA Astrophysics Data System (ADS)

The French National Library (BnF*) has launched many mass digitization projects in order to give access to its collection. The indexation of digital documents on Gallica (digital library of the BnF) is done through their textual content obtained thanks to service providers that use Optical Character Recognition softwares (OCR). OCR softwares have become increasingly complex systems composed of several subsystems dedicated to the analysis and the recognition of the elements in a page. However, the reliability of these systems is always an issue at stake. Indeed, in some cases, we can find errors in OCR outputs that occur because of an accumulation of several errors at different levels in the OCR process. One of the frequent errors in OCR outputs is the missed text components. The presence of such errors may lead to severe defects in digital libraries. In this paper, we investigate the detection of missed text components to control the OCR results from the collections of the French National Library. Our verification approach uses local information inside the pages based on Radon transform descriptors and Local Binary Patterns descriptors (LBP) coupled with OCR results to control their consistency. The experimental results show that our method detects 84.15% of the missed textual components, by comparing the OCR ALTO files outputs (produced by the service providers) to the images of the document.

Ben Salah, Ahmed; Ragot, Nicolas; Paquet, Thierry

2013-01-01

254

In-hospital cardiac arrest leads to chronic memory impairment  

Microsoft Academic Search

Objective: To assess the prevalence and severity of memory deficits in a group of patients who survived an in-hospital cardiac arrest (IHCA) in comparison with patients resuscitated after cardiac arrest outside hospital (OHCA) and patients with acute myocardial infarction (MI). Subjects: Thirty-five IHCA survivors, 35 OHCA survivors, and 35 patients who had suffered MI uncomplicated by cardiac arrest. Procedure: Participants

Samantha M O'Reilly; Neil R Grubb; Ronan E O'Carroll

2003-01-01

255

In-hospital cardiac arrest leads to chronic memory impairment  

Microsoft Academic Search

Objective : To assess the prevalence and severity of memory deficits in a group of patients who survived an in-hospital cardiac arrest (IHCA) in comparison with patients resuscitated after cardiac arrest outside hospital (OHCA) and patients with acute myocardial infarction (MI). Subjects : Thirty-five IHCA survivors, 35 OHCA survivors, and 35 patients who had suffered MI uncomplicated by cardiac arrest.

Samantha M. O'Reilly; Neil R. Grubb; Ronan E. O'Carroll

2003-01-01

256

Assessment of outcomes and differences between in- and out-of-hospital cardiac arrest patients treated with cardiopulmonary resuscitation using extracorporeal life support  

Microsoft Academic Search

AimCardiopulmonary resuscitation (CPR) using extracorporeal life support (ECLS) for in-hospital cardiac arrest (IHCA) patients has been assigned a low-grade recommendation in current resuscitation guidelines. This study compared the outcomes of IHCA and out-of-hospital cardiac arrest (OHCA) patients treated with ECLS.

Eisuke Kagawa; Ichiro Inoue; Takuji Kawagoe; Masaharu Ishihara; Yuji Shimatani; Satoshi Kurisu; Yasuharu Nakama; Kazuoki Dai; Otani Takayuki; Hiroki Ikenaga; Yoshimasa Morimoto; Kentaro Ejiri; Nozomu Oda

2010-01-01

257

Early loss of cardiac function in acute myocardial infarction is associated with redox imbalance  

PubMed Central

BACKGROUND: The loss of viable myocardium subsequent to myocardial infarction (MI) impairs cardiac function, and oxidative stress is considered to be critical in this process. OBJECTIVES: To assess cardiac function and correlate it with oxidative stress and antioxidant levels in cardiac tissue at 48 h post-MI. METHODS: Adult male Wistar rats (n=6 per group) with a mean (± SD) weight of 229±24 g were randomly assigned to either an infarcted group or a control group. MI was induced by occlusion of the left coronary artery. Cardiac function was evaluated by measuring left ventricular (LV) ejection fraction, LV fractional shortening, cardiac output, myocardial performance index and the peak early diastolic velocity/peak atrial velocity ratio using echocardiography. The myocardial oxidative stress profile was assessed by measuring the reduced glutathione/oxidized glutathione ratio, H2O2 levels, peroxiredoxin-6 protein levels and activity levels of superoxide dismutase, catalase and glutathione peroxidase. Lipid peroxidation was quantified using chemiluminescence, and protein oxidation was determined by measuring protein carbonyl levels. RESULTS: LV ejection fraction and LV fractional shortening were lower in the infarcted group compared with the sham group, whereas the peak early diastolic velocity/peak atrial velocity ratio and myocardial performance index were significantly increased, indicating systolic dysfunction. Lipid peroxidation, protein carbonyls and superoxide dismutase and catalase activity levels did not differ between the groups. Peroxyredoxin-6 levels were increased in the infarcted group, while H2O2 levels were reduced. The reduced glutathione/oxidized glutathione ratio and the glutathione peroxidase activity were reduced in the infarcted group compared with control. DISCUSSION AND CONCLUSION: These data suggest that MI-induced cardiac dysfunction and impaired redox balance may be associated with the activation of counter-regulatory responses to maintain reduced H2O2 concentrations and, thereby, prevent further oxidative damage at this early time point. PMID:23592951

Tavares, Angela Maria Vicente; da Rosa Araujo, Alex Sander; Llesuy, Susana; Khaper, Neelam; Rohde, Luis Eduardo; Clausell, Nadine; Belló-Klein, Adriane

2012-01-01

258

Databases for assessing the outcomes of the treatment of patients with congenital and paediatric cardiac disease--the perspective of anaesthesia.  

PubMed

The Congenital Cardiac Anesthesia Society was formed in 2005 by representatives from many of the busiest congenital cardiac surgical programs in North America and is now in the process of partnering with The Society of Thoracic Surgeons to create a joint congenital cardiac surgery and congenital cardiac anaesthesia database. Even the busiest of congenital cardiac programs have a low frequency of anaesthesia-related cardiac complications and deaths. One of the only mechanisms for accurately determining the incidence and outcomes of low frequency events is to aggregate large amounts of data from multiple sources. To that end, the Congenital Cardiac Anesthesia Society has joined with the Society of Thoracic Surgeons Congenital Database Task Force to incorporate anaesthesia-specific data points into their surgical registry, which is now the largest single reporting site for children and adults undergoing surgical repair of congenital cardiac malformations in North America. The Joint Congenital Cardiac Anesthesia Society--Society of Thoracic Surgeons Database will therefore become an optional module of The Society of Thoracic Surgeons Congenital Heart Surgery Database. Initial data fields have been selected and are presented in this article. Efforts are ongoing to make this initiative a global project. Initial collaborative discussions have taken place about the possibility of linking this initiative with the European Association of Cardiothoracic Anesthesiologists. It is certainly possible and desirable that the planned anaesthesia module of The Society of Thoracic Surgeons Congenital Heart Database has an identical module in the congenital heart database of The European Association for Cardio-Thoracic Surgery and The European Congenital Heart Surgeons Association. This project should also ideally spread beyond North America and Europe. Efforts to involve Africa, Asia, Australia, and South America are necessary and already underway. The creation of a joint cardiac surgery and anaesthesia database is another step towards the ultimate goal of creating a database for congenital heart disease that spans both geographical and subspecialty boundaries. PMID:19063782

Vener, David F; Jacobs, Jeffrey P; Schindler, Ehrenfried; Maruszewski, Bohdan; Andropoulos, Dean

2008-12-01

259

Cardiac failure and left ventricular assist devices  

Microsoft Academic Search

Congestive heart failure (CHF) is a clinical syndrome defined as chronic, in- adequate myocardial contraction and relaxation that results in decreased cardiac output. It has multiple etiologies, including coronary artery disease causing is- chemic changes, valvular heart disease, viral cardiomyopathies, and congenital disease.Amajorcause of morbidityand mortality inthe United States,CHF affects more than 4 million people each year and causes approximately

Douglas J. Hirsch; John R. Cooper

260

Cardiac abnormalities in liver cirrhosis.  

PubMed Central

Cirrhosis is associated with several circulatory abnormalities. A hyperkinetic circulation characterized by increased cardiac output and decreased arterial pressure and peripheral resistance is typical. Despite this hyperkinetic circulation, some patients with alcoholic cirrhosis have subclinical cardiomyopathy with evidence of abnormal ventricular function unmasked by physiologic or pharmacologic stress. Florid congestive alcoholic cardiomyopathy develops in a small percentage, but the concurrent presence of cirrhosis seems to retard the occurrence of overt heart failure. Even nonalcoholic cirrhosis may be associated with latent cardiomyopathy, although overt heart failure is not observed. Tense ascites is associated with some cardiac compromise, and removing or mobilizing ascitic fluid by paracentesis or peritoneovenous shunting results in short-term increases in cardiac output. Cirrhosis also appears to be associated with a decreased risk of major coronary atherosclerosis and an increased risk of bacterial endocarditis. Small hemodynamically insignificant pericardial effusions may be seen in ascitic patients. The release of atrial natriuretic peptide appears to be unimpaired in cirrhosis, although the kidney may be hyporesponsive to its natriuretic effects. PMID:2690463

Lee, S S

1989-01-01

261

Assessment of RCM output from the ENSEMBLES RT3 project in AMMA-region: focus on Senegal actual climate reproduction and effects on simulated crop yields  

NASA Astrophysics Data System (ADS)

In West-Africa countries, most economies and people depend on rainfed agriculture. In this area, rainfall is highly variable and, from the period 1931-1960 to 1968-1990, the annual rainfall has decreased 15 to 40%. Since the mid 1990's, an increase in rainfall is detected, but only to reach the level of 1970's rainfall. The aim of this study is to determine if large-scale fields, interpolated at local-scale are able (i) to reproduce observed climate at station and (ii) to simulate observed crop yields. Another objective of this study is to see if a combination of dynamical and statistical downscaling methods is useful to correct biases due to scale change. For that, we use data from some synoptic stations in Senegal and simulated data provided by the European project ENSEMBLES. Among research themes (RT) of this project, one (RT3) had the responsibility for providing improved climate model tools developed in the context of regional climate models (RCMs), at spatial scales of 50km at AMMA-region. RT3 provides 15-year experiments over West Africa driven by the ERA-INTERIM reanalysis of the ECMWF. A statistical method (CDF-transform), developed to generate local cumulative distribution functions of surface climate variables from large-scale fields is used to correct biases in RCM output, due to large-scale information basically interpolated at local-scale. In the present study, a deterministic crop model, SARRA-H, is used to simulate sorghum yields for the actual period, at local scale. This crop model simulates yield attainable under water-limited conditions by simulating the soil water balance, potential and actual evapotranspiration, phenology, potential and water-limited carbon assimilation, and biomass partitioning. SARRA-H model is driven by 4 meteorological datasets, at synoptic station scale: - observations, - ERA-INTERIM, - original RCM output, - corrected RCM output.

Oettli, Pascal; Sultan, Benjamin; Baron, Christian; Vrac, Mathieu

2010-05-01

262

CD62L (L-Selectin) Shedding for Assessment of Perioperative Immune Sensitivity in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass  

PubMed Central

Objective To investigate the suitability of blood granulocyte and monocyte sensitivity, as measured by the quantity of different agonists required to induce CD62L shedding, for assessment of perioperative immune changes in patients undergoing cardiac surgery with cardiopulmonary bypass. Methods Patients scheduled for aortocoronary bypass grafting or for valve surgery were included in this prospective observational study. Blood samples were drawn before anesthesia induction, directly after surgery and 48 hours after anesthesia induction. We determined the concentration of two different inflammatory stimuli – lipoteichoic acid (LTA) and tumor necrosis factor alpha (TNF) - required to induce shedding of 50% of surface CD62L from blood granulocytes and monocytes. In parallel monocyte surface human leukocyte antigen (HLA)-DR, and plasma interleukin (IL)-8, soluble (s)CD62L, soluble (s)Toll-like receptor (TLR)-2 and ADAM17 quantification were used to illustrate perioperative immunomodulation. Results 25 patients were enrolled. Blood granulocytes and monocytes showed decreased sensitivity to the TLR 2/6 agonist Staphylococcus aureus LTA immediately after surgery (p?=?0.001 and p?=?0.004 respectively). In contrast, granulocytes (p?=?0.01), but not monocytes (p?=?0.057) displayed a decreased postoperative sensitivity to TNF. We confirmed the presence of a systemic inflammatory response and a decreased immune sensitivity in the post-surgical period by measuring significant increases in the perioperative plasma concentration of IL-8 (p?0.001) and sTLR (p?=?0.004), and decreases in monocyte HLA-DR (p<0.001), plasma sCD62L (p?0.001). In contrast, ADAM17 plasma levels did not show significant differences over the observation period (p?=?0.401). Conclusions Monitoring granulocyte and monocyte sensitivity using the “CD62L shedding assay” in the perioperative period in cardiac surgical patients treated with the use of cardiopulmonary bypass reveals common changes in sensitivity to TLR2/6 ligands and to TNF stimulus. Further long-term follow-up studies will address the predictive value of these observations for clinical purposes. PMID:23301018

Erdoes, Gabor; Balmer, Maria L.; Slack, Emma; Kocsis, Istvan; Lehmann, Lutz E.; Eberle, Balthasar; Stüber, Frank; Book, Malte

2013-01-01

263

Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure  

SciTech Connect

Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the HDTV algorithm shows the best performance. At 50 mGy, the deviation from the reference obtained at 500 mGy were less than 4%. Also the LDPC algorithm provides reasonable results with deviation less than 10% at 50 mGy while PCF and MKB reconstruction show larger deviations even at higher dose levels. Conclusions: LDPC and HDTV increase CNR and allow for quantitative evaluations even at dose levels as low as 50 mGy. The left ventricular volumes exemplarily illustrate that cardiac parameters can be accurately estimated at lowest dose levels if sophisticated algorithms are used. This allows to reduce dose by a factor of 10 compared to today's gold standard and opens new options for longitudinal studies of the heart.

Maier, Joscha, E-mail: joscha.maier@dkfz.de [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)

2014-05-15

264

Comparison of accuracy of aortic root annulus assessment with cardiac magnetic resonance versus echocardiography and multidetector computed tomography in patients referred for transcatheter aortic valve implantation.  

PubMed

The evaluation of the aortic root in patients referred for transcatheter aortic valve implantation is crucial. The aim of the present study was to compare the accuracy of cardiac magnetic resonance (CMR) evaluation of the aortic annulus (AoA) with transthoracic and transesophageal echocardiography and multidetector computed tomography (MDCT) in patients referred for transcatheter aortic valve implantation. In 50 patients, maximum diameter, minimum diameter and AoA, length of the left coronary, right coronary, and noncoronary aortic leaflets, degree (grades 1 to 4) of aortic leaflet calcification, and distance between AoA and coronary artery ostia were assessed. AoA maximum diameter, minimum diameter, and area by CMR were 26.4 ± 2.8 mm, 20.6 ± 2.3 mm, 449.8 ± 86.2 mm(2), respectively. The length of left coronary, right coronary, and noncoronary leaflets by CMR were 13.9 ± 2.2, 13.3 ± 2.1, and 13.4 ± 1.8 mm, respectively, whereas the score of aortic leaflet calcifications was 2.9 ± 0.8. Finally, the distances between AoA and left main and right coronary artery ostia were 16.1 ± 2.8 and 16.1 ± 4.4 mm, respectively. Regarding AoA area, transthoracic and transesophageal echocardiography showed an underestimation (p <0.01), with a moderate agreement (r: 0.5 and 0.6, respectively, p <0.01) compared with CMR. No differences and excellent correlation were observed between CMR and MDCT for all parameters (r: 0.9, p <0.01), except for aortic leaflet calcifications that were underestimated by CMR. In conclusion, aortic root assessment with CMR including AoA size, aortic leaflet length, and coronary artery ostia height is accurate compared with MDCT. CMR may be a valid imaging alternative in patients unsuitable for MDCT. PMID:24045059

Pontone, Gianluca; Andreini, Daniele; Bartorelli, Antonio L; Bertella, Erika; Mushtaq, Saima; Gripari, Paola; Loguercio, Monica; Cortinovis, Sarah; Baggiano, Andrea; Conte, Edoardo; Beltrama, Virginia; Annoni, Andrea; Formenti, Alberto; Tamborini, Gloria; Muratori, Manuela; Guaricci, Andrea; Alamanni, Francesco; Ballerini, Giovanni; Pepi, Mauro

2013-12-01

265

A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 2: Case Study of Insulation (8 pp)  

Microsoft Academic Search

Goal, Scope and Background. In the first part of this paper, we developed a methodology to incorporate exposure and risk concepts into life cycle impact assessment (LCIA). We argued that both risk assessment and LCIA are needed to consider the impacts of increasing insulation for single-family homes in the US from current practice to the levels recommended by the 2000

Yurika Nishioka; Jonathan I. Levy; Gregory A. Norris; Deborah H. Bennett; John D. Spengler

2005-01-01

266

Visualization of Model Output  

NSDL National Science Digital Library

Visualization of output from mathematical or statistical models is one of the best ways to introduce introductory geoscience students to the results and behavior of sophisticated models. Example of good sites ...

267

Pacemaker current inhibition in experimental human cardiac sympathetic activation: a double-blind, randomized, crossover study.  

PubMed

Hyperpolarization-activated, cyclic nucleotide-gated 4 (HCN4) channels comprise the final pathway for autonomic heart rate (HR) regulation. We hypothesized that HCN4 inhibition could reverse autonomic imbalance in a human model of cardiac sympathetic activation. Nineteen healthy men ingested oral metoprolol+reboxetine, ivabradine+reboxetine, or placebo+reboxetine in a double-blind, randomized, crossover fashion. We assessed HR, blood pressure (BP), stroke volume, and cardiac output during rest and profound orthostatic stress. HR variability, BP variability, and baroreflex sensitivity were analyzed. Metoprolol, but not ivabradine, decreased resting HR and BP. Ivabradine attenuated the HR increase to orthostatic stress, albeit to a lesser extent than metoprolol. Stroke volume and cardiac output at a given HR were significantly lower with metoprolol. Unlike metoprolol, ivabradine did not affect HR variability, BP variability, or baroreflex sensitivity. Ivabradine attenuates sympathetic influences on HR at the sinus node level, leaving myocardial sympathetic activation unopposed. Reversal of parasympathetic dysfunction by ivabradine appears limited. PMID:24509430

Schroeder, C; Heusser, K; Zoerner, A A; Großhennig, A; Wenzel, D; May, M; Sweep, F C G J; Mehling, H; Luft, F C; Tank, J; Jordan, J

2014-06-01

268

Comparison of two- and three-dimensional transthoracic echocardiography to cardiac magnetic resonance imaging for assessment of paravalvular regurgitation after transcatheter aortic valve implantation.  

PubMed

This study evaluated 2-dimensional (2D) transthoracic echocardiography (TTE) using Valve Academic Research Consortium-2 (VARC-2) criteria and 3-dimensional (3D) TTE for assessment of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) in comparison with cardiac magnetic resonance (CMR) imaging. In 71 patients, 2D TTE, 3D TTE, and CMR imaging were performed to assess AR severity after TAVI. Using 2D TTE, AR severity was graded according to VARC-2 criteria and regurgitant volume (RVol) was determined. Three-dimensional color Doppler TTE allowed direct planimetry of the vena contracta area of the paravalvular regurgitation jet and calculation of the RVol as product with the velocity-time integral. RVol by CMR imaging was measured by phase-contrast velocity mapping in the ascending aorta. After TAVI, mean RVol determined by CMR imaging was 9.2 ± 9.6 ml/beat and mean regurgitant fraction was 13.3 ± 10.3%. AR was assessed as none or mild in 58 patients (82%) by CMR imaging. Correlation of 3D TTE and CMR imaging on RVol was better than correlation of 2D TTE and CMR imaging (r = 0.895 vs 0.558, p <0.001). There was good agreement between RVol by CMR imaging and by 3D TTE (mean bias = 2.4 ml/beat). Kappa on grading of AR severity was 0.357 between VARC-2 and CMR imaging versus 0.446 between 3D TTE and CMR imaging. Intraobserver variability for analysis of RVol of AR after TAVI was 73.5 ± 52.2% by 2D TTE, 16.7 ± 21.9% by 3D TTE, and 2.2 ± 2.0% by CMR imaging. In conclusion, 2D TTE considering VARC-2 criteria has limitations in the grading of AR severity after TAVI when CMR imaging is used for comparison. Three-dimensional TTE allows quantification of AR with greater accuracy than 2D TTE. Observer variability on RVol after TAVI is considerable using 2D TTE, significantly less using 3D TTE, and very low using CMR imaging. PMID:24837265

Altiok, Ertunc; Frick, Michael; Meyer, Christian G; Al Ateah, Ghazi; Napp, Andreas; Kirschfink, Annemarie; Almalla, Mohammad; Lotfi, Shahran; Becker, Michael; Herich, Lena; Lehmacher, Walter; Hoffmann, Rainer

2014-06-01

269

Prevention of cardiac allograft rejection by FK506 and rapamycin: assessment by histology and nuclear magnetic resonance.  

PubMed

We assessed the effect of FK506 and rapamycin (RPM) in a heterotopic abdominal rat heart transplant model using a major histocompatibility mismatch (DA to LEW). The end-point of our study was the histologic grading of rejection (Stanford) and 31P magnetic resonance spectroscopy (MRS) at 1 week after transplantation. Two dosages of FK506 (2.0 and 8.0 mg/kg per os daily) and RPM (1.5 and 6.0 mg/kg intraperitoneally daily) were compared in allografts without and with cyclosporine (12.5 mg/kg per os daily) treatment. The results show: Weak heartbeat and full rejection at day 5 in all untreated allografts; severe rejection in groups on a low dose of FK506 and RPM; mild rejection in both high dose groups comparable to the results of the hearts treated with cyclosporine; MRS does not allow differentiation between no or mild forms of rejection. Energy-rich phosphates are near normal in the high dosage immunosuppression groups but show a significant reduction in the low dosage groups. We conclude that all three tested drugs can reduce the degree of rejection from severe (untreated allografts) to mild if given in an adequate dosage. MRS correlates well with the degree of histologic rejection but permits only the diagnosis of moderate or severe rejection. PMID:14621877

Walpoth, B; Galdikas, J; Tschopp, A; Lazeyras, F; Altermatt, H J; Schaffner, T; Althaus, U; Billingham, M; Morris, R

1992-01-01

270

Biventricular Pacing (Cardiac Resynchronization Therapy)  

PubMed Central

Executive Summary Issue In 2002, (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on biventricular (BiV) pacing, also called cardiac resynchronization therapy (CRT). The goal of treatment with BiV pacing is to improve cardiac output for people in heart failure (HF) with conduction defect on ECG (wide QRS interval) by synchronizing ventricular contraction. The Medical Advisory Secretariat concluded that there was evidence of short (6 months) and longer-term (12 months) effectiveness in terms of cardiac function and quality of life (QoL). More recently, a hospital submitted an application to the Ontario Health Technology Advisory Committee to review CRT, and the Medical Advisory Secretariat subsequently updated its health technology assessment. Background Chronic HF results from any structural or functional cardiac disorder that impairs the ability of the heart to act as a pump. It is estimated that 1% to 5% of the general population (all ages) in Europe have chronic HF. (1;2) About one-half of the patients with HF are women, and about 40% of men and 60% of women with this condition are aged older than 75 years. The incidence (i.e., the number of new cases in a specified period) of chronic HF is age dependent: from 1 to 5 per 1,000 people each year in the total population, to as high as 30 to 40 per 1,000 people each year in those aged 75 years and older. Hence, in an aging society, the prevalence (i.e., the number of people with a given disease or condition at any time) of HF is increasing, despite a reduction in cardiovascular mortality. A recent study revealed 28,702 patients were hospitalized for first-time HF in Ontario between April 1994 and March 1997. (3) Women comprised 51% of the cohort. Eighty-five percent were aged 65 years or older, and 58% were aged 75 years or older. Patients with chronic HF experience shortness of breath, a limited capacity for exercise, high rates of hospitalization and rehospitalization, and die prematurely. (2;4) The New York Heart Association (NYHA) has provided a commonly used functional classification for the severity of HF (2;5): Class I: No limitation of physical activity. No symptoms with ordinary exertion. Class II: Slight limitations of physical activity. Ordinary activity causes symptoms. Class III: Marked limitation of physical activity. Less than ordinary activity causes symptoms. Asymptomatic at rest. Class IV: Inability to carry out any physical activity without discomfort. Symptoms at rest. The National Heart, Lung, and Blood Institute estimates that 35% of patients with HF are in functional NYHA class I; 35% are in class II; 25%, class III; and 5%, class IV. (5) Surveys (2) suggest that from 5% to 15% of patients with HF have persistent severe symptoms, and that the remainder of patients with HF is evenly divided between those with mild and moderately severe symptoms. Overall, patients with chronic, stable HF have an annual mortality rate of about 10%. (2) One-third of patients with new-onset HF will die within 6 months of diagnosis. These patients do not survive to enter the pool of those with “chronic” HF. About 60% of patients with incident HF will die within 3 years, and there is limited evidence that the overall prognosis has improved in the last 15 years. To date, the diagnosis and management of chronic HF has concentrated on patients with the clinical syndrome of HF accompanied by severe left ventricular systolic dysfunction. Major changes in treatment have resulted from a better understanding of the pathophysiology of HF and the results of large clinical trials. Treatment for chronic HF includes lifestyle management, drugs, cardiac surgery, or implantable pacemakers and defibrillators. Despite pharmacologic advances, which include diuretics, angiotensin-converting enzyme inhibitors, beta-blockers, spironolactone, and digoxin, many patients remain symptomatic on maximally tolerated doses. The Technology Owing to the limitations of drug therap

2005-01-01

271

Cardiac Mass and Function Decrease in Bronchiolitis Obliterans Syndrome after Lung Transplantation: Relationship to Physical Activity?  

PubMed Central

Rationale There is a need to expand knowledge on cardio-pulmonary pathophysiology of bronchiolitis obliterans syndrome (BOS) following lung transplantation (LTx). Objectives The purpose of this study was to assess MRI-derived biventricular cardiac mass and function parameters as well as flow hemodynamics in patients with and without BOS after LTx. Methods Using 1.5T cardiac MRI, measurements of myocardial structure and function as well as measurements of flow in the main pulmonary artery and ascending aorta were performed in 56 lung transplant patients. The patients were dichotomized into two gender matched groups of comparable age range: one with BOS (BOS stages 1–3) and one without BOS (BOS 0/0p). Measurements and Main Results Significantly lower biventricular cardiac mass, right and left ventricular end-diastolic volume, biventricular stroke volume, flow hemodynamics and significant higher heart rate but preserved cardiac output were observed in patients with BOS 1–3 compared to the BOS 0/0p group (p<0.05). In a stepwise logistic regression analysis global cardiac mass (p?=?0.046) and days after LTx (p?=?0.0001) remained independent parameters to predict BOS. In a second model an indicator for the physical fitness level - walking number of stairs - was added to the logistic regression model. In this second model, time after LTx (p?=?0.005) and physical fitness (p?=?0.01) remained independent predictors for BOS. Conclusion The observed changes in biventricular cardiac mass and function as well as changes in hemodynamic flow parameters in the pulmonary trunk and ascending aorta are likely attributed to the physical fitness level of patients after lung transplantation, which in turn is strongly related to lung function. PMID:25479016

Hinrichs, Jan B.; Renne, Julius; Schoenfeld, Christian; Gutberlet, Marcel; Haverich, Axel; Warnecke, Gregor; Welte, Tobias; Wacker, Frank

2014-01-01

272

Diagnostic pediatric cardiac catheterization: Experience of a tertiary care pediatric cardiac centre  

PubMed Central

Background Cardiac catheterization was considered gold standard for confirmation of diagnosis and analyzing various management issues in congenital heart diseases. In spite of development of various non invasive tools for investigation of cardiac disorders diagnostic catheterization still holds an important place in pediatric patients. Methods 300 consecutive diagnostic cardiac catheterization performed since April 2007 were included in this study. The study was undertaken to evaluate the profile of patients undergoing diagnostic cardiac catheterization, its results, assess its safety and its contribution toward solving various management issues. Result & Conclusion Children who underwent cardiac catheterization ranged in weight from 1.6 kg to 35 kg, with their age range 0 day–12 years. The information obtained was of great importance for further management in over 90% cases. The procedure of cardiac cath is invasive, still it was proved to be quite safe even in smallest baby. PMID:24623940

Kumar, Prabhat; Joshi, Vidya Sagar; Madhu, P.V.

2013-01-01

273

Protocol for the China PEACE (Patient-centered Evaluative Assessment of Cardiac Events) retrospective study of coronary catheterisation and percutaneous coronary intervention  

PubMed Central

Introduction During the past decade, the volume of percutaneous coronary intervention (PCI) in China has risen by more than 20-fold. Yet little is known about patterns of care and outcomes across hospitals, regions and time during this period of rising cardiovascular disease and dynamic change in the Chinese healthcare system. Methods and analysis Using the China PEACE (Patient-centered Evaluative Assessment of Cardiac Events) research network, the Retrospective Study of Coronary Catheterisation and Percutaneous Coronary Intervention (China PEACE-Retrospective CathPCI Study) will examine a nationally representative sample of 11?900 patients who underwent coronary catheterisation or PCI at 55 Chinese hospitals during 2001, 2006 and 2011. We selected patients and study sites using a two-stage cluster sampling design with simple random sampling stratified within economical-geographical strata. A central coordinating centre will monitor data quality at the stages of case ascertainment, medical record abstraction and data management. We will examine patient characteristics, diagnostic testing patterns, procedural treatments and in-hospital outcomes, including death, complications of treatment and costs of hospitalisation. We will additionally characterise variation in treatments and outcomes by patient characteristics, hospital, region and study year. Ethics and dissemination The China PEACE collaboration is designed to translate research into improved care for patients. The study protocol was approved by the central ethics committee at the China National Center for Cardiovascular Diseases (NCCD) and collaborating hospitals. Findings will be shared with participating hospitals, policymakers and the academic community to promote quality monitoring, quality improvement and the efficient allocation and use of coronary catheterisation and PCI in China. Registration details http://www.clinicaltrials.gov (NCT01624896). PMID:24607563

Li, Jing; Dharmarajan, Kumar; Li, Xi; Lin, Zhenqiu; Normand, Sharon-Lise T; Krumholz, Harlan M; Jiang, Lixin

2014-01-01

274

Diabetes and cardiac autonomic neuropathy: Clinical manifestations, cardiovascular consequences, diagnosis and treatment  

PubMed Central

Cardiac autonomic neuropathy (CAN) is a frequent chronic complication of diabetes mellitus with potentially life-threatening outcomes. CAN is caused by the impairment of the autonomic nerve fibers regulating heart rate, cardiac output, myocardial contractility, cardiac electrophysiology and blood vessel constriction and dilatation. It causes a wide range of cardiac disorders, including resting tachycardia, arrhythmias, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction and increased rate of mortality after myocardial infarction. Etiological factors associated with autonomic neuropathy include insufficient glycemic control, a longer period since the onset of diabetes, increased age, female sex and greater body mass index. The most commonly used methods for the diagnosis of CAN are based upon the assessment of heart rate variability (the physiological variation in the time interval between heartbeats), as it is one of the first findings in both clinically asymptomatic and symptomatic patients. Clinical symptoms associated with CAN generally occur late in the disease process and include early fatigue and exhaustion during exercise, orthostatic hypotension, dizziness, presyncope and syncope. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Medical therapies, including aldose reductase inhibitors, angiotensin-converting enzyme inhibitors, prostoglandin analogs and alpha-lipoic acid, have been found to be effective in randomized controlled trials. The following article includes the epidemiology, clinical findings and cardiovascular consequences, diagnosis, and approaches to prevention and treatment of CAN.

Balc?o?lu, Akif Serhat; Müderriso?lu, Haldun

2015-01-01

275

Diabetes and cardiac autonomic neuropathy: Clinical manifestations, cardiovascular consequences, diagnosis and treatment.  

PubMed

Cardiac autonomic neuropathy (CAN) is a frequent chronic complication of diabetes mellitus with potentially life-threatening outcomes. CAN is caused by the impairment of the autonomic nerve fibers regulating heart rate, cardiac output, myocardial contractility, cardiac electrophysiology and blood vessel constriction and dilatation. It causes a wide range of cardiac disorders, including resting tachycardia, arrhythmias, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction and increased rate of mortality after myocardial infarction. Etiological factors associated with autonomic neuropathy include insufficient glycemic control, a longer period since the onset of diabetes, increased age, female sex and greater body mass index. The most commonly used methods for the diagnosis of CAN are based upon the assessment of heart rate variability (the physiological variation in the time interval between heartbeats), as it is one of the first findings in both clinically asymptomatic and symptomatic patients. Clinical symptoms associated with CAN generally occur late in the disease process and include early fatigue and exhaustion during exercise, orthostatic hypotension, dizziness, presyncope and syncope. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Medical therapies, including aldose reductase inhibitors, angiotensin-converting enzyme inhibitors, prostoglandin analogs and alpha-lipoic acid, have been found to be effective in randomized controlled trials. The following article includes the epidemiology, clinical findings and cardiovascular consequences, diagnosis, and approaches to prevention and treatment of CAN. PMID:25685280

Balc?o?lu, Akif Serhat; Müderriso?lu, Haldun

2015-02-15

276

Assessing Right Ventricular Function in Patients with Hypertrophic Cardiomyopathy with Cardiac MRI: Correlation with the New York Heart Function Assessment (NYHA) Classification  

PubMed Central

Purpose To determine whether 3.0-T magnetic resonance imaging (MRI) could assess right ventricular (RV) function in patients with hypertrophic cardiomyopathy (HCM), and if this assessment is correlated with the New York Heart Function Assessment (NYHA) classification. Materials and Methods Forty-six patients with HCM and 23 normal individuals were recruited. Left and right ventricular function parameters including end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV) and ejection fraction (EF) and dimensions were measured and compared using 3.0-T MRI. RV function parameters between HCM patients and controls were compared using independent sample t tests. A one way ANOVA test with Bonferroni correction was used to determine significant differences among different NYHA groups. Receiver operating characteristic analyses calculated the sensitivity and specificity of RV dysfunction on MRI for the prediction of HCM severity. Results Statistical analysis revealed significant differences of left ventricular (LV) and RV volumetric values and masses between the HCM patients and controls (all p<0.05). Within the HCM group, the simultaneously decreased maximum RVEDD correlated well with the LVEDD (r?=?0.53; p<0.001). The function and dimension parameters among Class I to III were not determined to be significantly different (all p>0.05). However, significant differences between the Class IV and I-III groups (all P<0.0167) indicated that the diastolic and systolic function in both the RV and LV were impaired in Class IV patients. ROC analyses identified the EDV, ESV and EDD of both the LV and RV with a high sensitivity cutoff value to predict the HCM patients with severe heart failure (Class IV) with high sensitivity and specificity. Conclusions RV involvements were comparable to those of LV global function impairments in patients with HCM. The presence of RV dysfunction and decreased dimension on the MRI helped to predict the severe symptomatic HCM with high sensitivity and specificity. PMID:25180597

Zhang, Shuai; Sun, Jia-yu; Wen, Ling-yi; Xu, Hua-yan; Zhang, Ge

2014-01-01

277

Linear output nitinol engine  

SciTech Connect

This patent describes a linear output nitinol engine consisting of a number of integrated communicating parts. The engine has an external support framework which is described in detail. The patent further describes a wire transport mechanism, a pair of linkage levers with a loom secured to them, a number of nitinol wires strung between the looms, and a power takeoff block secured to the linkage levers. A pulley positioned in a flip-flop supporting bracket and a power takeoff modality including a tension member connected to a power output cable in order to provide linear power output transmission is described. A method for biasing the timing and the mechanism for timing the synchronization of the throw over arms and the flip-flop of the pulley are also described.

Banks, R.M.

1986-01-14

278

Cardiac MRI and Iron Overload Cardiomyopathy in Thalassemia Major: A Case Report  

PubMed Central

Introduction: Heart failure is the leading cause of death in patients with Thalassemia major and primarily results from transfusional iron overload. It is essential to assess myocardial iron load. Previous studies have shown that neither serum ferritin nor liver iron concentration gives a reliable measure of cardiac iron accumulation. Cardiac T2* MRI technique offers noninvasive measurement of myocardial iron load. Case Report: A 39-year-old man with a past medical history significant for beta thalassemia major requiring blood transfusions every three-weeks and on iron chelation, presented with a cough, high fevers, and chills. He was subsequently found to have community acquired pneumonia and was treated with ceftriaxone and doxycycline. His hospital course was significant for episodes of atrial fibrillation and non-sustained ventricular tachycardia. An echocardiogram showed normal left ventricular function with an ejection fraction of 70%, which hadn't changed from 2011. Although, the patient didn't have symptoms of heart failure, he likely had ventricular dysfunction that could be masked by the basal high cardiac output which can be seen in patients with chronic anemia and we decided to start the patient on sotalol 80 mg twice a day. The MRI software for multiecho T2* measurement was installed at Queens Medical Center in September 2011 and we were able to obtain images for our patient at that time. His myocardial T2* value was estimated to be 9 milliseconds which suggests an increased risk for the development of future cardiac arrhythmias and heart failure. The repeat cardiac MRI images after discharge showed 8 milliseconds which suggested an interval worsening of the iron deposition within the myocardium. Discussion: We were able to keep track of the progression of his iron cardiomyopathy, and start additional treatment. The patient continues to be followed by a hematologist for management of his hemochromatosis and a cardiologist for his infiltrative heart disease both resulting from his need for chronic blood transfusions. In patients with iron overload cardiomyopathy, their systolic function is preserved until a very late stage as iron deposition begins within the epicardium and extends to the myocardium. This case illustrates the importance of assessing cardiac iron content utilizing cardiac MRI as it is less invasive than cardiac biopsy and may show earlier involvement than echocardiogram.

Azuma, Steven

2014-01-01

279

Dynamic NMR cardiac imaging in a piglet.  

PubMed

NMR echo-planar imaging (EPI) has been used in a realtime mode to visualise the thorax of a live piglet. Moving pictures are available on an immediate image display system which demonstrates dynamic cardiac function. Frame rates vary from one per cardiac cycle in a prospective stroboscopic mode with immediate visual output to a maximum of 10 frames per second yielding up to six looks in one piglet heart cycle, but using a visual playback mode. A completely new system has been used to obtain these images, features of which include a probe assembly with 22 cm access and an AP400 array processor for real-time data processing. PMID:6652414

Doyle, M; Rzedzian, R; Mansfield, P; Coupland, R E

1983-12-01

280

Cardiac MRI  

MedlinePLUS

... Division of Intramural Research Research Resources Scientific Reports Technology Transfer Clinical Trials What Are Clinical Trials? Children & ... to diagnose and assess many diseases and conditions, including: Coronary heart disease Damage caused by a heart ...

281

Effects of Prior Intensive Versus Conventional Therapy and History of Glycemia on Cardiac Function in Type 1 Diabetes in the DCCT/EDIC  

PubMed Central

Intensive diabetes therapy reduces the prevalence of coronary calcification and progression of atherosclerosis and the risk of cardiovascular disease (CVD) events in the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study. The effects of intensive therapy on measures of cardiac function and structure and their association with glycemia have not been explored in type 1 diabetes (T1DM). We assess whether intensive treatment compared with conventional treatment during the DCCT led to differences in these parameters during EDIC. After 6.5 years of intensive versus conventional therapy in the DCCT, and 15 years of additional follow-up in EDIC, left ventricular (LV) indices were measured by cardiac magnetic resonance (CMR) imaging in 1,017 of the 1,371 members of the DCCT cohort. There were no differences between the DCCT intensive versus conventional treatment in end diastolic volume (EDV), end systolic volume, stroke volume (SV), cardiac output (CO), LV mass, ejection fraction, LV mass/EDV, or aortic distensibility (AD). Mean DCCT/EDIC HbA1c over time was associated with EDV, SV, CO, LV mass, LV mass/EDV, and AD. These associations persisted after adjustment for CVD risk factors. Cardiac function and remodeling in T1DM assessed by CMR in the EDIC cohort was associated with prior glycemic exposure, but there was no effect of intensive versus conventional treatment during the DCCT on cardiac parameters. PMID:23520132

Genuth, Saul M.; Backlund, Jye-Yu C.; Bayless, Margaret; Bluemke, David A.; Cleary, Patricia A.; Crandall, Jill; Lachin, John M.; Lima, Joao A.C.; Miao, Culian; Turkbey, Evrim B.

2013-01-01

282

Diodes stabilize LED output  

NASA Technical Reports Server (NTRS)

Small-signal diodes are placed in series with light-emitting diodes (LED's) to stabilize LED output against temperature fluctuations. Simple inexpensive method compensates for thermal fluctuations over a broad temperature range. Requiring few components, technique is particularly useful where circuit-board space is limited.

Deters, R. A.

1977-01-01

283

AN INTEGRATEDMICROELECTROMECHANICALRESONANT OUTPUT GYROSCOPE -  

E-print Network

AN INTEGRATEDMICROELECTROMECHANICALRESONANT OUTPUT GYROSCOPE - Ashwin A. Seshia*,Roger T. Howe vibratory rate gyroscope based on resonant sensing of the Coriolis force. The new design has several advantages over rate gyroscopes that utilize open-loop displacement sensing for rotation rate measurement

Tang, William C

284

An electricity-focused economic input-output model: Life-cycle assessment and policy implications of future electricity generation scenarios  

NASA Astrophysics Data System (ADS)

The electricity industry is extremely important to both our economy and our environment. We would like to be able to examine the economic, environmental and policy implications of both future electricity scenarios which include advanced generation technologies such as gasified coal, and of the products and processes which will use them, along with the interaction of this industry with the rest of the economy. This work builds upon an existing economic input-output framework, by adding detail about the electricity industry, specifically by differentiating among the various functions of the sector, and the different means of generating power. The mix of electricity consumed at any stage in the life-cycle of a product, process or industrial sector has a significant effect on the associated inventory of emissions. Fossil fuel or nuclear generators, large-scale hydroelectric, and renewable options such as geothermal, wind and solar each have a unique set of issues---both in the production of electricity at the plant and throughout the supply chain. Decision makers need better information regarding the environmental and economic impact of the electricity industry, including full supply chain details---the interaction of the electricity industry with the other 500 sectors of the economy. A systematic method for creating updated state level and sector generation mixes is developed. The results show that most sector mixes are very close to the U.S. average due to geographic dispersion of industries, but that some sectors are different, and they tend to be important raw material extraction or primary manufacturing industries. We then build a flexible framework for creating new sectors, supply chains and emission factors for the generation, transmission and distribution portions of the electricity industry. We look at scenarios of the present and future, for electricity and for particular products, and develop results which show environmental impacts split up by generation type, and with full supply chain detail. For analyses of the current electricity system and products, economic and environmental results match well with external verification sources, but for analyses of the future, there is significant uncertainty.

Marriott, Joe

285

B-type natriuretic peptide release and left ventricular filling pressure assessed by echocardiographic study after subarachnoid hemorrhage: a prospective study in non-cardiac patients  

Microsoft Academic Search

Introduction  Serum B-type natriuretic peptide (BNP) is frequently elevated after subarachnoid hemorrhage (SAH), but whether this high BNP\\u000a level is related to transient elevation of left ventricular filling pressure (LVFP) is unknown. However, in patients with\\u000a preexistent cardiac pathologies, it is impossible to differentiate between BNP elevation caused by chronic cardiac abnormalities\\u000a and BNP related to acute neurocardiac injury.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  All adult

Eric Meaudre; Christophe Jego; Nadia Kenane; Ambroise Montcriol; Henry Boret; Philippe Goutorbe; Gilbert Habib; Bruno Palmier

2009-01-01

286

An integrated bioimpedance--ECG gating technique for respiratory and cardiac motion compensation in cardiac PET.  

PubMed

Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6? ± ?3.3?mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4?ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3? ± ?1.3?mm) compared to cardiac-gated images (11.3? ± ?1.3?mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes. PMID:25295531

Koivumäki, Tuomas; Nekolla, Stephan G; Fürst, Sebastian; Loher, Simone; Vauhkonen, Marko; Schwaiger, Markus; Hakulinen, Mikko A

2014-11-01

287

An integrated bioimpedance—ECG gating technique for respiratory and cardiac motion compensation in cardiac PET  

NASA Astrophysics Data System (ADS)

Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6? ± ?3.3?mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4?ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3? ± ?1.3?mm) compared to cardiac-gated images (11.3? ± ?1.3?mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes.

Koivumäki, Tuomas; Nekolla, Stephan G.; Fürst, Sebastian; Loher, Simone; Vauhkonen, Marko; Schwaiger, Markus; Hakulinen, Mikko A.

2014-10-01

288

Statistical Comparison of Cardiac Fibre Architectures  

Microsoft Academic Search

In this paper, a statistical atlas of DT-MRIs based on a population of nine ex vivo normal canine hearts is compared with a human cardiac DT-MRI and with a synthetic model of the fibre orientation. The aim\\u000a of this paper is to perform a statistical inter-species comparison of the cardiac fibre architecture and to assess the quality\\u000a of a synthetic

Jean-marc Peyrat; Maxime Sermesant; Xavier Pennec; Hervé Delingette; Chenyang Xu; Elliot R. Mcveigh; Nicholas Ayache

2007-01-01

289

Increase of ventricular output inducing ventricular afterpotential sensing and ventricular safety pacing in a biventricular implanted cardioverter defibrillator.  

PubMed

Programming maximum right ventricular output in a patient with a biventricular implanted cardioverter defibrillator resulted in ventricular oversensing and ventricular safety pacing in the same cardiac cycle. PMID:19801565

van Elsäcker, André; Nikolic, Tanja; Scheffer, Mike G; van Gelder, Berry M

2010-01-01

290

Cardiac electrophysiology in mice: a matter of size  

PubMed Central

Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. PMID:22973235

Kaese, Sven; Verheule, Sander

2012-01-01

291

Assessment of radiochromic gel dosimeter based on Turnbull Blue dye for relative output factor measurements of the Leksell Gamma Knife® PerfexionTM  

NASA Astrophysics Data System (ADS)

The aim of the study was to perform assessment of radiochromic gel dosimeter based on Turnbull blue dye formed by irradiation (TB gel dosimeter) for measurement of ROFs for 4 mm and 8 mm collimators for the Leksell Gamma Knife PerfexionTM. All measurements have been carried out using home-made spherical Perspex glass phantom of diameter 160 mm. TB gel dosimeters were scanned using homemade optical CT scanner. The results are compared with vendor recommended Monte Carlo calculated ROFs values of 0.814 and 0.900 for 4 mm and 8 mm collimators, respectively. The comparisons between the gel measurements and the treatment planning system (TPS) calculation are presented in the form of 2D isodoses for the central slices and 1D profile. Measured ROF 0.746 and 0.874 for 4 mm and 8 mm collimators respectively are in a reasonable agreement with vendor recommended values and measured relative dose distribution in a central slice and measured profiles of all shots show excellent correspondence with TPS.

Kozubikova, P.; Solc, J.; Novotny, J., Jr.; Pilarova, K.; Pipek, J.; Koncekova, J.

2015-01-01

292

A methodology for fast assessments to the electrical activity of barrel fields in vivo: from population inputs to single unit outputs  

PubMed Central

Here we propose a methodology to analyze volumetric electrical activity of neuronal masses in the somatosensory barrel field of Wistar rats. The key elements of the proposed methodology are a three-dimensional microelectrode array, which was customized by our group to observe extracellular recordings from an extended area of the barrel field, and a novel method for the current source density analysis. By means of this methodology, we were able to localize single barrels from their event-related responses to single whisker deflection. It was also possible to assess the spatiotemporal dynamics of neuronal aggregates in several barrels at the same time with the resolution of single neurons. We used simulations to study the robustness of our methodology to unavoidable physiological noise and electrode configuration. We compared the accuracy to reconstruct neocortical current sources with that obtained with a previous method. This constitutes a type of electrophysiological microscopy with high spatial and temporal resolution, which could change the way we analyze the activity of cortical neurons in the future. PMID:24550785

Riera, Jorge J.; Goto, Takakuni; Kawashima, Ryuta

2014-01-01

293

Cardiac output and cardiac contractility by impedance cardiography during exercise of runners  

NASA Technical Reports Server (NTRS)

Most of the solid state electronic engineering of the system now generally known as the Minnesota Impedance Cardiograph was performed with the support of a five-year contract, NAS9-4500, with the NASA Lyndon B. Johnson Space Center, Houston, Texas. This contract ran from 1965 to 1970. In addition to the engineering design and development of the hardware, the contract called for testing on both animals and human subjects. This project also provided funds to construct twenty impedance cardiographs and place them in selected research and clinical facilities for further evaluation. This, then, led to the First Symposium on Impedance Cardiography, held at the NASA Lyndon B. Johnson Space Center, Houston, Texas, 2-4 June 1969. Twenty-four excellent papers were presented.

Kubicek, W. G.; Tracy, R. A.

1994-01-01

294

Physician Compliance With Advanced Cardiac Life Support Guidelines  

Microsoft Academic Search

Study objective: To determine compliance with advanced cardiac life support (ACLS) guidelines among ACLS-certified and non-ACLS-certified physicians.Design: Retrospective review of consecutive cardiac arrests between July 1989 and June 1990, including assessment of the resuscitation leaders' ACLS certification. Setting and participants: All nontraumatic prehospital and hospital cardiac arrests in a rural university hospital. Results: Two hundred seven arrests were studied for

David M Cline; Kenneth J Welch; Lisa S Cline; Charles K Brown

1995-01-01

295

Central Venous Saturation: A Prognostic Tool in Cardiac Surgery patients  

Microsoft Academic Search

Background: Central venous oxygen saturation (ScvO2) is a valuable prognostic marker in sepsis. However, its value in cardiac surgery has not been assessed yet. This study aimed at evaluating ScvO2 as a tool for predicting short-term organ dysfunction (OD) after cardiac surgery. Methods: A prospective cohort including cardiac surgery patients submitted to a goal-oriented therapy to maintain ScvO2 above 70%

Pedro M. Nogueira; Hugo T. Mendonça-Filho; Luiz Antonio Campos; Renato V. Gomes; Alexandre R. Felipe; Marco A. Fernandes; Cristiane A. Villela-Nogueira; José R. Rocco

2010-01-01

296

Antioxidant treatment improves neonatal survival and prevents impaired cardiac function at adulthood following neonatal glucocorticoid therapy.  

PubMed

Glucocorticoids are widely used to treat chronic lung disease in premature infants but their longer-term adverse effects on the cardiovascular system raise concerns. We reported that neonatal dexamethasone treatment in rats induced in the short term molecular indices of cardiac oxidative stress and cardiovascular tissue remodelling at weaning, and that neonatal combined antioxidant and dexamethasone treatment was protective at this time. In this study, we investigated whether such effects of neonatal dexamethasone have adverse consequences for NO bioavailability and cardiovascular function at adulthood, and whether neonatal combined antioxidant and dexamethasone treatment is protective in the adult. Newborn rat pups received daily i.p. injections of a human-relevant tapering dose of dexamethasone (D; n = 8; 0.5, 0.3, 0.1 ?g g(-1)) or D with vitamins C and E (DCE; n = 8; 200 and 100 mg kg(-1), respectively) on postnatal days 1-3 (P1-3); vitamins were continued from P4 to P6. Controls received equal volumes of vehicle from P1 to P6 (C; n = 8). A fourth group received vitamins alone (CCE; n = 8). At P100, plasma NO metabolites (NOx) was measured and isolated hearts were assessed under both Working and Langendorff preparations. Relative to controls, neonatal dexamethasone therapy increased mortality by 18% (P < 0.05). Surviving D pups at adulthood had lower plasma NOx concentrations (10.6 ± 0.8 vs. 28.0 ± 1.5 ?M), an increased relative left ventricular (LV) mass (70 ± 2 vs. 63 ± 1%), enhanced LV end-diastolic pressure (14 ± 2 vs. 8 ± 1 mmHg) and these hearts failed to adapt output with increased preload (cardiac output: 2.9 ± 2.0 vs. 10.6 ± 1.2 ml min(-1)) or afterload (cardiac output: -5.3 ± 2.0 vs.1.4 ± 1.2 ml min(-1)); all P < 0.05. Combined neonatal dexamethasone with antioxidant vitamins improved postnatal survival, restored plasma NOx and protected against cardiac dysfunction at adulthood. In conclusion, neonatal dexamethasone therapy promotes cardiac dysfunction at adulthood. Combined neonatal treatment with antioxidant vitamins is an effective intervention. PMID:23940378

Niu, Youguo; Herrera, Emilio A; Evans, Rhys D; Giussani, Dino A

2013-10-15

297

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

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

Nelson, O Lynne; Rourke, Bryan C

2013-12-15

298

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

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

Nelson, O. Lynne; Rourke, Bryan C.

2013-01-01

299

Autophagy-mediated degradation is necessary for regression of cardiac hypertrophy during ventricular unloading.  

PubMed

Cardiac hypertrophy occurs in response to a variety of stresses as a compensatory mechanism to maintain cardiac output and normalize wall stress. Prevention or regression of cardiac hypertrophy can be a major therapeutic target. Although regression of cardiac hypertrophy occurs after control of etiological factors, the molecular mechanisms remain to be clarified. In the present study, we investigated the role of autophagy in regression of cardiac hypertrophy. Wild-type mice showed cardiac hypertrophy after continuous infusion of angiotensin II for 14 days using osmotic minipumps, and regression of cardiac hypertrophy was observed 7 days after removal of the minipumps. Autophagy was induced during regression of cardiac hypertrophy, as evidenced by an increase in microtubule-associated protein 1 light chain 3 (LC3)-II protein level. Then, we subjected cardiac-specific Atg5-deficient (CKO) and control mice (CTL) to angiotensin II infusion for 14 days. CKO and CTL developed cardiac hypertrophy to a similar degree without contractile dysfunction. Seven days after removal of the minipumps, CKO showed significantly less regression of cardiac hypertrophy compared with CTL. Regression of pressure overload-induced cardiac hypertrophy after unloading was also attenuated in CKO. These results suggest that autophagy is necessary for regression of cardiac hypertrophy during unloading of neurohumoral and hemodynamic stress. PMID:24211573

Oyabu, Jota; Yamaguchi, Osamu; Hikoso, Shungo; Takeda, Toshihiro; Oka, Takafumi; Murakawa, Tomokazu; Yasui, Hiroki; Ueda, Hiromichi; Nakayama, Hiroyuki; Taneike, Manabu; Omiya, Shigemiki; Shah, Ajay M; Nishida, Kazuhiko; Otsu, Kinya

2013-11-29

300

Assessment of cardiac safety during fingolimod treatment initiation in a real-world relapsing multiple sclerosis population: a phase 3b, open-label study.  

PubMed

The aim of this study was to evaluate short-term safety and tolerability of fingolimod in a real-world population with relapsing multiple sclerosis, focusing on cardiac safety during treatment initiation. Patients received fingolimod 0.5 mg once daily for four months. Patients excluded from the pivotal studies with certain pre-existing cardiac conditions or baseline cardiac findings (PCCs), and those receiving beta blockers (BBs) and/or calcium channel blockers (CCBs), were eligible. Heart rate (HR) and electrical conduction events were monitored using ambulatory electrocardiography for at least 6 h after the first dose. Of 2,417 enrolled patients, 2,282 (94.4 %) completed the study. Fingolimod initiation was associated with a transient, mostly asymptomatic decrease in HR. Bradycardia adverse events occurred in 0.6 % of patients and were more frequent in individuals receiving BBs/CCBs (3.3 %) than in other patient subgroups (0.5-1.4 %); most events were asymptomatic, and all patients recovered without pharmacological intervention. In the 6 h post-dose, the incidences of Mobitz type I second-degree atrioventricular block (AVB) and 2:1 AVB were higher in patients with PCCs (4.1 and 2.0 %, respectively) than in those without (0.9 and 0.3 %, respectively); at pre-dose screening, patients with PCCs had the same incidence of Mobitz type I second-degree AVB (4.1 %) and a slightly lower incidence of 2:1 AVB (0.7 %) than 6 h post-dose. All recorded conduction abnormalities were asymptomatic. This study adds to the evidence showing that cardiac effects during fingolimod initiation remain consistent with those known from previous, controlled studies, even if patients with PCCs are included. PMID:24221641

Gold, Ralf; Comi, Giancarlo; Palace, Jacqueline; Siever, Arno; Gottschalk, Rebecca; Bijarnia, Mahendra; von Rosenstiel, Philipp; Tomic, Davorka; Kappos, Ludwig

2014-02-01

301

Decreased passive stiffness of cardiac myocytes and cardiac tissue from copper-deficient rat hearts.  

PubMed

Passive stiffness characteristics of isolated cardiac myocytes, papillary muscles, and aortic strips from male Holtzman rats fed a copper-deficient diet for approximately 5 wk were compared with those of rats fed a copper-adequate diet to determine whether alterations in these characteristics might accompany the well-documented cardiac hypertrophy and high incidence of ventricular rupture characteristic of copper deficiency. Stiffness of isolated cardiac myocytes was assessed from measurements of cellular dimensional changes to varied osmotic conditions. Stiffness of papillary muscles and aortic strips was determined from resting length-tension analyses and included steady-state characteristics, dynamic viscoelastic stiffness properties, and maximum tensile strength. The primary findings were that copper deficiency resulted in cardiac hypertrophy with increased cardiac myocyte size and fragility, decreased cardiac myocyte stiffness, and decreased papillary muscle passive stiffness, dynamic stiffness, and tensile strength and no alteration in aortic connective tissue passive stiffness or tensile strength. These findings suggest that a reduction of cardiac myocyte stiffness and increased cellular fragility could contribute to the reduced overall cardiac tissue stiffness and the high incidence of ventricular aneurysm observed in copper-deficient rats. PMID:10843880

Heller, L J; Mohrman, D E; Prohaska, J R

2000-06-01

302

Cardiac and muscular involvement in idiopathic inflammatory myopathies: noninvasive diagnostic assessment and the role of cardiovascular and skeletal magnetic resonance imaging.  

PubMed

Idiopathic inflammatory myopathies (IIMs) are rare autoimmune diseases and include dermatomyositis, polymyositis, necrotizing myopathy and inclusion body myositis; they are characterized by inflammation of skeletal muscle and other internal organs and may potentially lead to irreversible damage and death. Only a small percentage of IIM has clinically overt cardiac disease; however, heart involvement is one of the leading causes of death and therefore, early detection remains a challenge. Biochemical markers and non-invasive methods such as the electrocardiogram and echocardiography have a role in diagnosis, but lack sensitivity in identifying patients with early, sublinical cardiac abnormalities. Endomyocardial and skeletal muscle biopsies are very useful, but invasive techniques and cannot be used for routine follow-up. Cardiac and skeletal magnetic resonance imaging, due to their capability to perform tissue characterization, has emerged as novel techniques for the early detection and follow-up of myocardial and skeletal muscle tissue changes (oedema, inflammation, fibrosis) in IIM. However, the clinical implications of using these approaches and their cost /benefit ratio require further evaluation. PMID:24863256

Mavrogeni, Sophie; Sfikakis, Petros P; Dimitroulas, Theodoros; Kolovou, Genovefa; Kitas, George D

2014-01-01

303

Incidence, Diagnosis and Prognosis of Cardiac Amyloidosis  

PubMed Central

Background and Objectives Cardiac involvement is frequent in systemic amyloidosis and is the most important determinant of the clinical outcome. The aims of this study were to assess the incidence and prognosis of cardiac amyloidosis and discuss the diagnostic issues related to cardiac amyloidosis. Subjects and Methods We retrospectively studied all patients diagnosed with systemic amyloidosis who presented to our institution from January 1999 to December 2011. Results Of the 129 patients with systemic amyloidosis, cardiac amyloidosis was diagnosed in 62 patients. At the 3 years' follow-up of the patients with systemic amyloidosis, there was a statistically significant difference in mortality between patients with cardiac amyloidosis and the rest of the patients (58.1% vs. 37.3%, p=0.008). In the Cox proportional hazard model, old age {hazard ratio (HR) 18.336, p=0.006}, elevation of cardiac troponin I (cTNI) (HR 13.246, p=0.020), left ventricular (LV) systolic dysfunction (HR 5.137, p=0.041) and diastolic dysfunction (HR 64.595, p=0.022) were independently associated with survival in cardiac amyloidosis. In the diagnosis of monoclonal gammopathy, serum or urine protein electrophoresis was not sensitive enough to be used clinically compared to serum free light chain assay (35.8% vs. 96.4%). Conclusion In systemic amyloidosis, cardiac involvement was the most important determinant of the prognosis, and old age, elevation of cTNI, LV systolic dysfunction and diastolic dysfunction were independently associated with survival in cardiac amyloidosis. PMID:24363751

Lee, Min-Ho; Lee, Seung-Pyo; Kim, Yong-Jin

2013-01-01

304

Cardiac Effects of Persistent Hemodialysis Arteriovenous Access in Recipients of Renal Allograft  

Microsoft Academic Search

In hemodialysis patients, large arteriovenous (AV) fistulas for vascular access may cause ventricular hypertrophy and high-output cardiac failure. The long-term cardiac consequences of functional AV fistulas in renal transplant patients are unclear. A precise knowledge of these consequences is important to decide if and when such fistulas should be closed in successfully transplanted patients. In this retrospective study including 61

José Jayme G. De Lima; Marcelo Luis Campos Vieira; Laszlo J. Molnar; Caio Jorge Medeiros; Luís Estevan Ianhez; Eduardo M. Krieger

1999-01-01

305

New horizons in cardiac imaging  

SciTech Connect

The emphasis in cardiac diagnosis in recent years has been on noninvasive imaging techniques that enable anatomic diagnosis and physiologic assessment of the severity of disease. Echocardiography and radionuclide imaging were early noninvasive techniques that are now central to cardiovascular diagnosis. During the past few years, three new imaging modalities have been introduced: magnetic resonance (MR), ultrafast computed tomography (cine CT), and positron emission tomography (PET). These new techniques enable the following to be done noninvasively: depiction of internal cardiac anatomy, characterization of myocardial tissue, quantitation of blood flow, estimation and perhaps quantitation of regional myocardial perfusion, quantitation of regional myocardial contraction, and in vivo sampling of myocardial metabolism. Some of the capabilities of the new imaging modalities will be reviewed, and the likely role for each in the clinical and investigative study of cardiovascular disease will be proposed.

Higgins, C.B.

1985-09-01

306

[Cardiac magnetic resonance imaging (MRI)].  

PubMed

TECHNOLOGICAL PROGRESS: Although cardiac magnetic resonance imaging (MRI) is now recognised as the imaging method of choice for the morphological study of the heart, recent technological progress have widened its indications to functional analysis of the heart rate, perfusion and contractility. FUNCTIONAL ASSESSMENT: The possibility of conducting pharmacological stress tests enhances the functional exploration of cardiac perfusion and contractility. The rapid sequences in apnea, tissue marking and injection of contrast products are all elements that help to refine the study of the locoregional consequences of an ischemia: does the myocardial tissue contract normally? Is it sufficiently perfused? Is it still viable? THE BENEFITS OF A NON-INVASIVE TECHNIQUE: The MRI offers clinicians a non-invasive and non-radiating imaging technique that is the perfect supplement to echocardiography. A reliable angio-coronary LRI technique would, for the first time, permit exploration of the coronary vascularisation, tissue perfusion and resulting contractility. PMID:15387389

Vignaux, Olivier

2004-07-31

307

doi:10.1155/2011/631062 Clinical Study Assessment of Procalcitonin to Predict Outcome in Hypothermia-Treated Patients after Cardiac Arrest  

E-print Network

Copyright © 2011 Pascal Stammet et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Objective. Determine the potential of procalcitonin (PCT) to predict neurological outcome after hypothermia treatment following cardiac arrest. Methods. Retrospective analysis of patient data over a 2-year period. Mortality and neurological outcome of survivors were determined 6 months after cardiac arrest using the Cerebral Performance Category (CPC) score. Results. Datafrom53 consecutive patients were analyzed. Median age was 63 (54–71) and 79 % were male. Twenty-seven patients had good outcome (CPC ? 2) whereas 26 had severe neurological sequelae or died (CPC 3–5). At 48 h, after regaining normothermia, PCT was significantly higher in patients with bad outcome compared to those with good outcome: 3.38 (1.10–24.48) versus 0.28 (0– 0.75) ng/mL (P <0.001). PCT values correlated with bad neurological outcome (r = 0.54, P = 0.00004) and predicted outcome with an area under the curve of 0.84 (95 % CI 0.73–0.96). A cutoff point of 1 ng/mL provided a sensitivity of 85 % and a specificity of 81%. Above a PCT level of 16 ng/mL, no patient regained consciousness. PCT provided an additive value over simplified acute physiology score II. Conclusions. PCT might be an ancillary marker for outcome prediction after cardiac arrest treated by induced hypothermia. 1.

Pascal Stammet; Yvan Devaux; Francisco Azuaje; Christophe Werer; Christiane Lorang; Georges Gilson; Martin Max

308

Multidetector CT and MR Imaging of Cardiac Tumors  

PubMed Central

The purpose of this article is to provide a current review of the spectrum of multidetector CT (MDCT) and MRI findings for a variety of cardiac neoplasms. In the diagnosis of cardiac tumors, the use of MDCT and MRI can help differentiate benign from malignant masses. Especially, the use of MDCT is advantageous in providing anatomical information and MRI is useful for tissue characterization of cardiac masses. Knowledge of the characteristic MRI findings of benign cardiac tumors or thrombi can be helpful to avoid unnecessary surgical procedures. Presurgical assessment of malignant cardiac tumors with the use of MDCT and MRI may allow determination of the resectability of tumors and planning for the reconstruction of cardiac chambers. PMID:19270863

Kim, Eun Young; Sung, Kiick; Park, Seung Woo; Kim, Ji Hye; Ko, Young-Hyeh

2009-01-01

309

Quantitative assessment of brain tissue oxygenation in porcine models of cardiac arrest and cardiopulmonary resuscitation using hyperspectral near-infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy (NIRS) is a non-invasive tool to measure real-time tissue oxygenation in the brain. In an invasive animal experiment we were able to directly compare non-invasive NIRS measurements on the skull with invasive measurements directly on the brain dura matter. We used a broad-band, continuous-wave hyper-spectral approach to measure tissue oxygenation in the brain of pigs under the conditions of cardiac arrest, cardiopulmonary resuscitation (CPR), and defibrillation. An additional purpose of this research was to find a correlation between mortality due to cardiac arrest and inadequacy of the tissue perfusion during attempts at resuscitation. Using this technique we measured the changes in concentrations of oxy-hemoglobin [HbO2] and deoxy-hemoglobin [HHb] to quantify the tissue oxygenation in the brain. We also extracted cytochrome c oxidase changes ?[Cyt-Ox] under the same conditions to determine increase or decrease in cerebral oxygen delivery. In this paper we proved that applying CPR, [HbO2] concentration and tissue oxygenation in the brain increase while [HHb] concentration decreases which was not possible using other measurement techniques. We also discovered a similar trend in changes of both [Cyt-Ox] concentration and tissue oxygen saturation (StO2). Both invasive and non-invasive measurements showed similar results.

Lotfabadi, Shahin S.; Toronov, Vladislav; Ramadeen, Andrew; Hu, Xudong; Kim, Siwook; Dorian, Paul; Hare, Gregory M. T.

2014-03-01

310

THE CARDIOVASCULAR RESPONSES OF THE RED-EARED SLIDER (TRACHEMYS SCRIPTA) ACCLIMATED TO EITHER 22 OR 5 °C I. EFFECTS OF ANOXIC EXPOSURE ON IN VIVO CARDIAC PERFORMANCE  

Microsoft Academic Search

The extreme anoxia-tolerance of freshwater turtles under cold conditions is well documented, but little is known about their cardiac performance in such situations. Using chronic catheterization techniques, we measured systemic cardiac power output (POsys), systemic cardiac output (Q. sys), heart rate (fH), systemic stroke volume (Vs,sys), systemic resistance (Rsys) and mean arterial pressure (Psys) in red-eared sliders (Trachemys scripta). The

J. M. T. HICKS; A. P. FARRELL

311

Challenges in Predicting Power Output from Offshore Wind Farms  

E-print Network

Challenges in Predicting Power Output from Offshore Wind Farms R. J. Barthelmie1 and S. C. Pryor2 Abstract: Offshore wind energy is developing rapidly in Europe and the trend is towards large wind farms an offshore wind farm, accurate assessment of the wind resource/power output from the wind farm is a necessity

Pryor, Sara C.

312

Input and Output Analysis of Suburban Elementary School Districts.  

ERIC Educational Resources Information Center

The relationship of certain input variables to output was determined by a multiple regression analysis, using a sample of 44 suburban elementary school districts. The four input factors were: (1) socioeconomic characteristics, (2) assessed valuation, (3) per-pupil operating expenditure, and (4) educational treatments. The output was mean scores on…

Dunnell, John P.

313

Inflation Targeting and Output Growth: Evidence from Aggregate European Data  

E-print Network

1 Inflation Targeting and Output Growth: Evidence from Aggregate European Data Nicholas Apergis inflation targeting and assesses its merits by comparing alternative targets in a macroeconomic model. We inflation targets in terms of output losses. We employ two major alternative policy rules, forward

Ahmad, Sajjad

314

Cardiac involvement in Wegener's granulomatosis.  

PubMed Central

Wegener's granulomatosis is a systemic inflammatory disorder of unknown aetiology. The protean clinical presentations depend on the organ(s) involved and the degree of progression from a local to a systemic arteritis. The development of serological tests (antieutrophil cytoplasmic antibodies) allows easier diagnosis of a disease whose incidence is increasing. This is particularly helpful where the presentation is not classic--for example "overlap syndromes"--or where the disease presents early in a more localised form. This is true of cardiac involvement, which is traditionally believed to be rare, but may not be as uncommon as has hitherto been thought (< or = 44%). This involvement may be subclinical or the principal source of symptoms either in the form of localised disease or as part of a systemic illness. Pericarditis, arteritis, myocarditis, valvulitis, and arrhythmias are all recognised. Wegener's granulomatosis should therefore be considered in the differential diagnosis of any non-specific illness with cardiac involvement. This includes culture negative endocarditis, because Wegener's granulomatosis can produce systemic upset with mass lesions and vasculitis. Echocardiography and particularly transoesophageal echocardiography can easily identify and delineate cardiac and proximal aortic involvement and may also be used to assess response to treatment. Images PMID:7696016

Goodfield, N. E.; Bhandari, S.; Plant, W. D.; Morley-Davies, A.; Sutherland, G. R.

1995-01-01

315

Cardiac Procedures and Surgeries  

MedlinePLUS

Cardiac Procedures and Surgeries Updated:Oct 24,2014 If you've had a heart attack, you may have already had certain procedures to ... artery disease (CAD) you have. Cardiac Procedures and Surgeries Angioplasty Also known as Percutaneous Coronary Interventions [PCI], ...

316

Cardiac sarcoidosis: contemporary review.  

PubMed

Cardiac sarcoidosis can occur in up to 25% of patients with sarcoidosis in other organ systems and may present with conduction abnormalities, ventricular arrhythmias, or heart failure. This review will summarize the state of current knowledge and key questions that remain to be answered. Because cardiac sarcoidosis is a rare, complex disease, the most meaningful research will include interdisciplinary, multicenter collaborations. PMID:25231794

Kron, Jordana; Ellenbogen, Kenneth A

2015-01-01

317

Cardiac Hegemony of Senescence  

PubMed Central

Cardiac senescence and age-related disease development have gained general attention and recognition in the past decades due to increased accessibility and quality of health care. The advancement in global civilization is complementary to concerns regarding population aging and development of chronic degenerative diseases. Cardiac degeneration has been rigorously studied. The molecular mechanisms of cardiac senescence are on multiple cellular levels and hold a multilayer complexity level, thereby hampering development of unambiguous treatment protocols. In particular, the synergistic exchange of the senescence phenotype through a senescence secretome between myocytes and stem cells appears complicated and is of great future therapeutic value. The current review article will highlight hallmarks of senescence, cardiac myocyte and stem cell senescence, and the mutual exchange of senescent secretome. Future cardiac cell therapy approaches require a comprehensive understanding of myocardial senescence to improve therapeutic efficiency as well as efficacy. PMID:24349878

Siddiqi, Sailay; Sussman, Mark A.

2013-01-01

318

Cardiac Hegemony of Senescence.  

PubMed

Cardiac senescence and age-related disease development have gained general attention and recognition in the past decades due to increased accessibility and quality of health care. The advancement in global civilization is complementary to concerns regarding population aging and development of chronic degenerative diseases. Cardiac degeneration has been rigorously studied. The molecular mechanisms of cardiac senescence are on multiple cellular levels and hold a multilayer complexity level, thereby hampering development of unambiguous treatment protocols. In particular, the synergistic exchange of the senescence phenotype through a senescence secretome between myocytes and stem cells appears complicated and is of great future therapeutic value. The current review article will highlight hallmarks of senescence, cardiac myocyte and stem cell senescence, and the mutual exchange of senescent secretome. Future cardiac cell therapy approaches require a comprehensive understanding of myocardial senescence to improve therapeutic efficiency as well as efficacy. PMID:24349878

Siddiqi, Sailay; Sussman, Mark A

2013-12-01

319

Achieving elongated lesions employing cardiac cryoablation: a preclinical evaluation study.  

PubMed

Cardiac cryoablation applied for treating cardiac arrhythmias has shown promising results after intervention, particularly for the creation of elongated lesions. A model for simulating and assessing cryoablation interventions was developed, evaluated and validated with animal experiments. We employed two simulations of different freezing outlet settings for a loop shaped cryocatheter, applying Pennes heat equation for cardiac tissue. Our experiments demonstrated that an equidistantly spaced freezing outlet distribution of 5mm led to an improved formation of lesions, i.e., elongated lesions were observed throughout the transmural cardiac volume and on the epicardial structure. A complete transmural frozen lesion was not achieved with a freezing outlet distance of 10mm. These simulation results could be experimentally verified by morphological and histological examinations. Using our simulation model we were able to optimize the intervention procedure by predicting and assessing the freezing process. This should further increase the success rate of cardiac cryoablation in clinical interventions. PMID:22580465

Seger, M; Fischer, G; Handler, M; Stöger, M; Nowak, C-N; Hintringer, F; Klima, G; Baumgartner, C

2012-10-01

320

Impact of epoetin alfa on left ventricular structure, function, and pressure volume relations as assessed by cardiac magnetic resonance: the heart failure preserved ejection fraction (HFPEF) anemia trial.  

PubMed

Anemia, a common comorbidity in older adults with heart failure and a preserved ejection fraction (HFPEF), is associated with worse outcomes. The authors quantified the effect of anemia treatment on left ventricular (LV) structure and function as measured by cardiac magnetic resonance (CMR) imaging. A prospective, randomized single-blind clinical trial (NCT NCT00286182) comparing the safety and efficacy of epoetin alfa vs placebo for 24 weeks in which a subgroup (n=22) had cardiac magnetic resonance imaging (MRI) at baseline and after 3 and 6 months to evaluate changes in cardiac structure and function. Pressure volume (PV) indices were derived from MRI measures of ventricular volume coupled with sphygmomanometer-measured pressure and Doppler estimates of filling pressure. The end-systolic and end-diastolic PV relations and the area between them as a function of end-diastolic pressure, the isovolumic PV area (PVAiso), were calculated. Patients (75±10 years, 64% women) with HFPEF (EF=63%±15%) with an average hemoglobin of 10.3±1.1 gm/dL were treated with epoetin alfa using a dose-adjusted algorithm that increased hemoglobin compared with placebo (P<.0001). As compared with baseline, there were no significant changes in end-diastolic (-7±8 mL vs -3±8 mL, P=.81) or end-systolic (-0.4±2 mL vs -0.7±5 mL, P=.96) volumes at 6-month follow-up between epoetin alfa compared with placebo. LV function as measured based on EF (-1.5%±1.6% vs -2.6%±3.3%, P=.91) and pressure volume indices (PVAiso-EDP at 30 mm Hg, -5071±4308 vs -1662±4140, P=.58) did not differ between epoetin alfa and placebo. Administration of epoetin alfa to older adult patients with HFPEF resulted in a significant increase in hemoglobin, without evident change in LV structure, function, or pressure volume relationships as measured quantitatively using CMR imaging. PMID:23517485

Green, Philip; Babu, Benson A; Teruya, Sergio; Helmke, Stephen; Prince, Martin; Maurer, Mathew S

2013-01-01

321

Lightweight multiple output converter development  

NASA Technical Reports Server (NTRS)

A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams.

Kisch, J. J.; Martinelli, R. M.

1978-01-01

322

Effect of Electronarcosis on Oxygen Consumption and Carbon Dioxide Output  

Microsoft Academic Search

IN assessing changes of vital function during electronarcosis, we measured oxygen consumption and carbon dioxide output in an experiment in rabbits. The measured values were considered an important index for the evaluation of metabolic changes during electronarcosis.

Jaroslav Strmiska; Antonín Vacek

1960-01-01

323

Serial Input Output  

SciTech Connect

Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each stream, record or block name must be unique in its category (i.e. all streams must have different names, but a stream can have the same name as a record). Each category is an arbitrary length list which is handled by a 'manager' and there is one manager for each category.

Waite, Anthony; /SLAC

2011-09-07

324

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

PubMed

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. PMID:18043164

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

325

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

PubMed Central

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

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

326

Assessment of anti-arrhythmic activity of antipsychotic drugs in an animal model: Influence of non-cardiac ?1-adrenergic receptors.  

PubMed

Torsades de Pointes (TdP) is a potentially lethal cardiac arrhythmia and a known adverse effect of many drugs secondary to block of the rapidly activating delayed rectifier potassium current (IKr). In animal models antipsychotic drugs have shown reduced pro-arrhythmic potential compared to drugs with comparable IKr-blocking characteristics. The reduced pro-arrhythmic properties of antipsychotic drugs has been attributed to a variety of different causes e.g., effects on ?1-adrenergic receptors, ?-adrenergic receptors, muscarinic receptors or cardiac ion channels like Ca(2+)- and Na(+)-channels. Since only limited experimental information exists about the effects of ?1-adrenergic receptor activity of antipsychotic drugs in pro-arrhythmic models, we have decided to investigate this. In this study we show that four antipsychotic drugs all have high affinity for ?1-adrenergic receptor (sertindole>risperidone>haloperidol>olanzapine) and all block IKr (sertindole>haloperidol>risperidone>olanzapine). In canine Purkinje fibres, ?1-adrenergic stimulation prolonged action potential duration; however, the stimulation does not cause afterdepolarizations, even in the presence of dofetilide-induced delayed repolarization. We showed for the first time in an in vivo pro-arrhythmic rabbit model that several antipsychotic drugs in accordance with their known ?1-adrenergic receptor blocking properties reduced the incidence of drug-induced TdP and that the overall ability of the antipsychotic drugs to prevent TdP was associated with prevention of methoxamine induced increase in blood pressure. Further investigations are required to clarify the relative importance of ?1-adrenergic receptor antagonism in conjunction with the additional effects of antipsychotic drugs on various receptors and ion channels. PMID:25530269

Mow, Tomas; Frederiksen, Kristen; Thomsen, Morten B

2015-02-01

327

Factors influencing the outcome of paediatric cardiac surgical patients during extracorporeal circulatory support  

PubMed Central

Background Veno-arterial extracorporeal membrane oxygenation (ECMO) is a common modality of circulatory assist device used in children. We assessed the outcome of children who had ECMO following repair of congenital cardiac defects (CCD) and identified the risk factors associated with hospital mortality. Methods From April 1990 to December 2003, 53 patients required ECMO following surgical correction of CCD. Retrospectively collected data was analyzed with univariate and multivariate logistic regression analysis. Results Median age and weight of the patients were 150 days and 5.4 kgs respectively. The indications for ECMO were low cardiac output in 16, failure to wean cardiopulmonary bypass in 13, cardiac arrest in 10 and cardio-respiratory failure in 14 patients. The mean duration of ECMO was 143 hours. Weaning off from ECMO was successful in 66% and of these 83% were survival to hospital-discharge. 37.7% of patients were alive for the mean follow-up period of 75 months. On univariate analysis, arrhythmias, ECMO duration >168 hours, bleeding complications, renal replacement therapy on ECMO, arrhythmias and cardiac arrest after ECMO were associated with hospital mortality. On multivariate analysis, abnormal neurology, bleeding complications and arrhythmias after ECMO were associated with hospital mortality. Extra and intra-thoracic cannulations were used in 79% and 21% of patients respectively and extra-thoracic cannulation had significantly less bleeding complications (p = 0.031). Conclusion ECMO provides an effective circulatory support following surgical repair of CCD in children. Extra-thoracic cannulation is associated with less bleeding complications. Abnormal neurology, bleeding complications on ECMO and arrhythmias after ECMO are poor prognostic indicators for hospital survival. PMID:17217529

Balasubramanian, Sendhil K; Tiruvoipati, Ravindranath; Amin, Mohammed; Aabideen, Kanakkande K; Peek, Giles J; Sosnowski, Andrew W; Firmin, Richard K

2007-01-01

328

Cardiac cystic echinococcosis: Report of three cases.  

PubMed

We present a retrospective analysis of three cases of cardiac hydatidosis, who underwent surgery between 2010 and 2012. Two patients had a lesion in the interventricular septum, whereas one patient had the lesion in apicoinferior wall of LV. The diagnosis was made by echocardiography, but magnetic resonance imaging was utilized to assess cyst activity and extend of disease. All patients were placed on cardiopulmonary bypass. No postoperative complication or death occurred. The patients discharged uneventfully and all of them were free from hydatid disease at two years follow-up. We concluded that cardiac hydatid cysts should be removed surgically regardless of their location or extent, even in asymptomatic patients. PMID:25441996

Alta?, Ozge; Sar?kaya, Sabit; Saç?, Hakan; Yerlikhan, Onur; K?rali, Kaan

2014-11-01

329

[Clinical usefulness of biomarkers in cardiac failure].  

PubMed

The assessment of patients with a suspected cardiac failure aims to an early and precise diagnosis and risk stratification. Only natriuretic peptides have demonstrated to be clinically useful. Brain natriuretic peptide stands out due to its diagnostic and prognostic value. However its results should be cautiously interpreted in the clinical context, bearing in mind possible confounders. The combination of markers can provide a better risk stratification and compensates the limitations of individual markers. Each new marker gives a new insight on the underlying physiopathology of cardiac failure and proposes new therapeutic approaches. PMID:24728434

Paredes C, Alejandro; Vega, Julián; de León, Ana; Kanacri, Andrés; Castro, Pablo; Baeza, Ricardo

2013-12-01

330

Defining cardiac adaptations and safety of endurance training in patients with m.3243A>G-related mitochondrial disease??????  

PubMed Central

Background Cardiac hypertrophic remodelling and systolic dysfunction are common in patients with mitochondrial disease and independent predictors of morbidity and early mortality. Endurance exercise training improves symptoms and skeletal muscle function, yet cardiac adaptations are unknown. Methods and results Before and after 16-weeks of training, exercise capacity, cardiac magnetic resonance imaging and phosphorus-31 spectroscopy, disease burden, fatigue, quality of life, heart rate variability (HRV) and blood pressure variability (BPV) were assessed in 10 adult patients with m.3243A>G-related mitochondrial disease, and compared to age- and gender-matched sedentary control subjects. At baseline, patients had increased left ventricular mass index (LVMI, p < 0.05) and LV mass to end-diastolic volume ratio, and decreased longitudinal shortening and myocardial phosphocreatine/adenosine triphosphate ratio (all p < 0.01). Peak arterial–venous oxygen difference (p < 0.05), oxygen uptake (VO2) and power were decreased in patients (both p < 0.01) with no significant difference in cardiac power output. All patients remained stable and completed ? 80% sessions. With training, there were similar proportional increases in peak VO2, anaerobic threshold and work capacity in patients and controls. LVMI increased in both groups (p < 0.01), with no significant effect on myocardial function or bioenergetics. Pre- and post-exercise training, HRV and BPV demonstrated increased low frequency and decreased high frequency components in patients compared to controls (all p < 0.05). Conclusion Patients with mitochondrial disease and controls achieved similar proportional benefits of exercise training, without evidence of disease progression, or deleterious effects on cardiac function. Reduced exercise capacity is largely mediated through skeletal muscle dysfunction at baseline and sympathetic over-activation may be important in pathogenesis. PMID:23742928

Bates, Matthew G.D.; Newman, Jane H.; Jakovljevic, Djordje G.; Hollingsworth, Kieren G.; Alston, Charlotte L.; Zalewski, Pawel; Klawe, Jacek J.; Blamire, Andrew M.; MacGowan, Guy A.; Keavney, Bernard D.; Bourke, John P.; Schaefer, Andrew; McFarland, Robert; Newton, Julia L.; Turnbull, Douglass M.; Taylor, Robert W.; Trenell, Michael I.; Gorman, Gráinne S.

2013-01-01

331

Molecular Basis of Cardiac Myxomas  

PubMed Central

Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis. PMID:24447924

Singhal, Pooja; Luk, Adriana; Rao, Vivek; Butany, Jagdish

2014-01-01

332

Institutional causes of output volatility  

Microsoft Academic Search

The authors investigate the relationship between the quality of institutions and output volatility. Using instrumental variable regressions, they address whether higher entry barriers and lower property rights protection lead to higher volatility. They find that a 1-standard-deviation increase in entry costs increases the standard deviation of output growth by roughly 40 percent of its average value in the sample. In

Levon Barseghyan; Riccardo DiCecio

2010-01-01

333

Enhanced performance CCD output amplifier  

DOEpatents

A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

Dunham, Mark E. (Los Alamos, NM); Morley, David W. (Santa Fe, NM)

1996-01-01

334

Update on cardiac imaging techniques 2013.  

PubMed

Cardiac imaging is a cornerstone of diagnosis in heart conditions, and an essential tool for assessing prognosis and establishing treatment decisions. This year, echocardiography stands out as a guide in interventional procedures and in choosing the size of the prosthesis. It is also proving to be a valuable technique in low-flow, low-gradient aortic stenosis. Three-dimensional echocardiography is advancing our knowledge of cardiac anatomy and valvular measurements. The parameters indicating tissue deformation have predictive power in valve disease and in the follow-up of drug-induced cardiotoxicity. Single-photon emission computed tomography and positron emission tomography are proving useful in ischemic heart disease and in the diagnosis of cardiac inflammation and infections. The role of computed tomography has been strengthened in noninvasive coronary angiography, the emergency room management of chest pain, assessment of chronic occlusions, and morphologic study of coronary plaque. Cardiac magnetic resonance imaging remains the gold standard for tissue characterization in ischemic heart disease and cardiomyopathies, and is assuming a greater role in stress studies and in the assessment of myocardial viability. PMID:24795120

García-Orta, Rocío; Mahía-Casado, Patricia; Gómez de Diego, José J; Barba-Cosials, Joaquín; Rodriguez-Palomares, José F; Aguadé-Bruix, Santiago; Candell-Riera, Jaume

2014-02-01

335

Abnormal cardiac enzymes in systemic sclerosis: a report of four patients and review of the literature.  

PubMed

Cardiac involvement in systemic sclerosis (SSc) is heterogeneous and can include primary involvement of the myocardium, pericardium and coronary arteries or be secondary to cardiac complications of pulmonary and renal disease. Primary cardiac involvement in SSc is uncommon but can result in ventricular dysfunction, organ failure, arrhythmias and death. It can remain clinically silent and the prevalence is likely to be under-reported. We report four cases of SSc associated with a raised serum troponin T (TnT), in a proportion of whom cardiac MRI myocardial abnormalities were detected. These cases highlight the heterogeneity of cardiac involvement in SSc, the role of cardiac MRI and promising biochemical responses to immunosuppression. Cardiac biomarkers such as TnT may be useful screening tools to identify subclinical cardiac disease and assess response to therapeutic intervention. PMID:24091585

Vasta, B; Flower, V; Bucciarelli-Ducci, C; Brown, S; Korendowych, E; McHugh, N J; Pauling, J D

2014-03-01

336

Electrical stimulation systems for cardiac tissue engineering  

PubMed Central

We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

2009-01-01

337

Cardiac tissue engineering using perfusion bioreactor systems  

PubMed Central

This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

2009-01-01

338

Electrical stimulation systems for cardiac tissue engineering.  

PubMed

We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

2009-01-01

339

Methodological approach for the assessment of ultrasound reproducibility of cardiac structure and function: a proposal of the study group of Echocardiography of the Italian Society of Cardiology (Ultra Cardia SIC) Part I  

PubMed Central

When applying echo-Doppler imaging for either clinical or research purposes it is very important to select the most adequate modality/technology and choose the most reliable and reproducible measurements. Quality control is a mainstay to reduce variability among institutions and operators and must be obtained by using appropriate procedures for data acquisition, storage and interpretation of echo-Doppler data. This goal can be achieved by employing an echo core laboratory (ECL), with the responsibility for standardizing image acquisition processes (performed at the peripheral echo-labs) and analysis (by monitoring and optimizing the internal intra- and inter-reader variability of measurements). Accordingly, the Working Group of Echocardiography of the Italian Society of Cardiology decided to design standardized procedures for imaging acquisition in peripheral laboratories and reading procedures and to propose a methodological approach to assess the reproducibility of echo-Doppler parameters of cardiac structure and function by using both standard and advanced technologies. A number of cardiologists experienced in cardiac ultrasound was involved to set up an ECL available for future studies involving complex imaging or including echo-Doppler measures as primary or secondary efficacy or safety end-points. The present manuscript describes the methodology of the procedures (imaging acquisition and measurement reading) and provides the documentation of the work done so far to test the reproducibility of the different echo-Doppler modalities (standard and advanced). These procedures can be suggested for utilization also in non referall echocardiographic laboratories as an "inside" quality check, with the aim at optimizing clinical consistency of echo-Doppler data. PMID:21943283

2011-01-01

340

Autonomic cardiac innervation  

PubMed Central

Autonomic cardiac neurons have a common origin in the neural crest but undergo distinct developmental differentiation as they mature toward their adult phenotype. Progenitor cells respond to repulsive cues during migration, followed by differentiation cues from paracrine sources that promote neurochemistry and differentiation. When autonomic axons start to innervate cardiac tissue, neurotrophic factors from vascular tissue are essential for maintenance of neurons before they reach their targets, upon which target-derived trophic factors take over final maturation, synaptic strength and postnatal survival. Although target-derived neurotrophins have a central role to play in development, alternative sources of neurotrophins may also modulate innervation. Both developing and adult sympathetic neurons express proNGF, and adult parasympathetic cardiac ganglion neurons also synthesize and release NGF. The physiological function of these “non-classical” cardiac sources of neurotrophins remains to be determined, especially in relation to autocrine/paracrine sustenance during development.   Cardiac autonomic nerves are closely spatially associated in cardiac plexuses, ganglia and pacemaker regions and so are sensitive to release of neurotransmitter, neuropeptides and trophic factors from adjacent nerves. As such, in many cardiac pathologies, it is an imbalance within the two arms of the autonomic system that is critical for disease progression. Although this crosstalk between sympathetic and parasympathetic nerves has been well established for adult nerves, it is unclear whether a degree of paracrine regulation occurs across the autonomic limbs during development. Aberrant nerve remodeling is a common occurrence in many adult cardiovascular pathologies, and the mechanisms regulating outgrowth or denervation are disparate. However, autonomic neurons display considerable plasticity in this regard with neurotrophins and inflammatory cytokines having a central regulatory function, including in possible neurotransmitter changes. Certainly, neurotrophins and cytokines regulate transcriptional factors in adult autonomic neurons that have vital differentiation roles in development. Particularly for parasympathetic cardiac ganglion neurons, additional examinations of developmental regulatory mechanisms will potentially aid in understanding attenuated parasympathetic function in a number of conditions, including heart failure. PMID:23872607

Hasan, Wohaib

2013-01-01

341

Cardiac Rehabilitation After Acute Myocardial Infarction Resuscitated From Cardiac Arrest  

PubMed Central

Objective To examine the safety and effectiveness of cardiac rehabilitation on patients resuscitated from cardiac arrest due to acute myocardial infarction. Methods The study included 23 subjects, including 8 with history of cardiac arrest and 15 without history of cardiac arrest. Both groups underwent initial graded exercise test (GXT) and subsequent cardiac rehabilitation for 6 weeks. After 6 weeks, both groups received follow-up GXT. Results Statistically significant (p<0.05) increase of VO2peak and maximal MVO2 but significant (p<0.05) decrease of submaximal MVO2 and resting heart rate were observed in both groups after 6 weeks of cardiac rehabilitation. An increasing trend of maximal heart rates was observed in both groups. However, the increase was not statistically significant (p>0.05). There was no statistically significant change of resting heart rate, maximal heart rate, maximal MVO2, or submaximal MVO2 in both groups after cardiac rehabilitation. Fatal cardiac complications, such as abnormal ECG, cardiac arrest, death or myocardial infarction, were not observed. All subjects finished the cardiac rehabilitation program. Conclusion Improvement was observed in the exercise capacity of patients after aerobic exercise throughout the cardiac rehabilitation program. Therefore, cardiac rehabilitation can be safely administered for high-risk patients with history of cardiac arrest. Similar improvement in exercise capacity can be expected in patients without cardiac arrest experience. PMID:25566479

Kim, Chul; Choi, Hee Eun; Kang, Seong Hoon

2014-01-01

342

Influence of Cardiac Decentralization on Cardioprotection  

PubMed Central

The role of cardiac nerves on development of myocardial tissue injury after acute coronary occlusion remains controversial. We investigated whether acute cardiac decentralization (surgical) modulates coronary flow reserve and myocardial protection in preconditioned dogs subject to ischemia-reperfusion. Experiments were conducted on four groups of anesthetised, open-chest dogs (n?=?32): 1- controls (CTR, intact cardiac nerves), 2- ischemic preconditioning (PC; 4 cycles of 5-min IR), 3- cardiac decentralization (CD) and 4- CD+PC; all dogs underwent 60-min coronary occlusion and 180-min reperfusion. Coronary blood flow and reactive hyperemic responses were assessed using a blood volume flow probe. Infarct size (tetrazolium staining) was related to anatomic area at risk and coronary collateral blood flow (microspheres) in the anatomic area at risk. Post-ischemic reactive hyperemia and repayment-to-debt ratio responses were significantly reduced for all experimental groups; however, arterial perfusion pressure was not affected. Infarct size was reduced in CD dogs (18.6±4.3; p?=?0.001, data are mean±1SD) compared to 25.2±5.5% in CTR dogs and was less in PC dogs as expected (13.5±3.2 vs. 25.2±5.5%; p?=?0.001); after acute CD, PC protection was conserved (11.6±3.4 vs. 18.6±4.3%; p?=?0.02). In conclusion, our findings provide strong evidence that myocardial protection against ischemic injury can be preserved independent of extrinsic cardiac nerve inputs. PMID:24236106

Kingma, John G.; Simard, Denys; Voisine, Pierre; Rouleau, Jacques R.

2013-01-01

343

Gastrodin protects against cardiac hypertrophy and fibrosis.  

PubMed

Phenolic glucoside gastrodin (Gas), which is a main component extracted from the Chinese herbs Gastrodia elata Bl, is a well-known natural calcium antagonist with antioxidant and anti-inflammatory functions. It has long been used clinically for treatment of cardiovascular and cerebrovascular diseases. Previous studies have shown that gastrodin possesses comprehensive pharmacological functions. However, very little is known about whether gastrodin has protective role on cardiac hypertrophy. The aim of this study was to determine whether gastrodin attenuates pressure overload-induced cardiac hypertrophy in mice and to clarify the underlying molecular mechanisms. Our data demonstrated that gastrodin prevented cardiac hypertrophy induced by aortic banding (AB), as assessed by heart weight/body weight and lung weight/body weight ratios, echocardiographic parameters, and gene expression of hypertrophic markers. The inhibitory effect of gastrodin on cardiac hypertrophy is mediated by ERK1/2 signaling and GATA-4 activation. Further studies showed that gastrodin attenuated fibrosis and collagen synthesis through abrogating ERK1/2 signaling pathway. Therefore, these findings indicated that gastrodin, which is a potentially safe and inexpensive therapy for clinical use, has protective potential in targeting cardiac hypertrophy and fibrosis through suppression of ERK1/2 signaling. PMID:21833534

Shu, Chunming; Chen, Changgui; Zhang, Da-Ping; Guo, Haipeng; Zhou, Heng; Zong, Jing; Bian, Zhouyan; Dong, Xuan; Dai, Jia; Zhang, Yan; Tang, Qizhu

2012-01-01

344

Cardiopulmonary resuscitation and management of cardiac arrest.  

PubMed

The best chance of survival with a good neurological outcome after cardiac arrest is afforded by early recognition and high-quality cardiopulmonary resuscitation (CPR), early defibrillation of ventricular fibrillation (VF), and subsequent care in a specialist center. Compression-only CPR should be used by responders who are unable or unwilling to perform mouth-to-mouth ventilations. After the first defibrillator shock, further rhythm checks and defibrillation attempts should be performed after 2 min of CPR. The underlying cause of cardiac arrest can be identified and treated during CPR. Drugs have a limited effect on long-term outcomes after cardiac arrest, although epinephrine improves the success of resuscitation, and amiodarone increases the success of defibrillation for refractory VF. Supraglottic airway devices are an alternative to tracheal intubation, which should be attempted only by skilled rescuers. Care after cardiac arrest includes controlled reoxygenation, therapeutic hypothermia for comatose survivors, percutaneous coronary intervention, circulatory support, and control of blood-glucose levels and seizures. Prognostication in comatose survivors of cardiac arrest needs a careful, multimodal approach using clinical and electrophysiological assessments after at least 72 h. PMID:22665327

Nolan, Jerry P; Soar, Jasmeet; Wenzel, Volker; Paal, Peter

2012-09-01

345

Image-Based Patient-Specific Ventricle Models with Fluid-Structure Interaction for Cardiac Function Assessment and Surgical Design Optimization  

PubMed Central

Recent advances in medical imaging technology and computational modeling techniques are making it possible that patient-specific computational ventricle models be constructed and used to test surgical hypotheses and replace empirical and often risky clinical experimentation to examine the efficiency and suitability of various reconstructive procedures in diseased hearts. In this paper, we provide a brief review on recent development in ventricle modeling and its potential application in surgical planning and management of tetralogy of Fallot (ToF) patients. Aspects of data acquisition, model selection and construction, tissue material properties, ventricle layer structure and tissue fiber orientations, pressure condition, model validation and virtual surgery procedures (changing patient-specific ventricle data and perform computer simulation) were reviewed. Results from a case study using patient-specific cardiac magnetic resonance (CMR) imaging and right/left ventricle and patch (RV/LV/Patch) combination model with fluid-structure interactions (FSI) were reported. The models were used to evaluate and optimize human pulmonary valve replacement/insertion (PVR) surgical procedure and patch design and test a surgical hypothesis that PVR with small patch and aggressive scar tissue trimming in PVR surgery may lead to improved recovery of RV function and reduced stress/strain conditions in the patch area. PMID:21344066

Tang, Dalin; Yang, Chun; Geva, Tal; del Nido, Pedro J.

2010-01-01

346

The prognostic value of cardiac dysfunction assessed by bedside echocardiography in critically ill patients with COPD requiring mechanical ventilation: a study protocol  

PubMed Central

Introduction Chronic obstructive lung disease is not only a major cause of morbidity and mortality, but is also the major reason for intensive care unit (ICU) admission. Cardiac function is often impaired in this disease, but its association with clinical outcome has not been fully established. Methods and analysis This is a prospective observational study conducted in a 47-bed mixed ICU of a tertiary academic teaching hospital. The study will be performed from January 2014 to December 2015. All patients meeting the diagnostic criteria of acute exacerbation of chronic obstructive pulmonary disease and admitted to the ICU are potentially eligible for the present study. The relevant demographics and laboratory measurements have been obtained. Transthoracic echocardiography was performed immediately after ICU admission by experienced intensivists. The Cox proportional hazard regression model has been fitted by using a stepwise forward selection and backward elimination technique. If linear assumption is not satisfied, the linear spline function will be used. Ethics and dissemination The study protocol was approved by the ethics committee of Jinhua municipal central hospital. The results will be published in a peer-reviewed journal and shared with the worldwide medical community. Trial registration number The study protocol is registered at ClinicalTrials.gov (NCT02099279). PMID:25256186

Zhang, Zhongheng; Chen, Lin; Chen, Kun; Ni, Hongying

2014-01-01

347

Impairment of cardiac function and energetics in experimental renal failure.  

PubMed Central

Cardiac function and energetics in experimental renal failure in the rat (5/6 nephrectomy) have been investigated by means of an isolated perfused working heart preparation and an isometric Langendorff preparation using 31P nuclear magnetic resonance (31P NMR). 4 wk after nephrectomy cardiac output of isolated hearts perfused with Krebs-Henseleit buffer was significantly lower (P < 0.0001) at all levels of preload and afterload in the renal failure groups than in the pair-fed sham operated control group. In control hearts, cardiac output increased with increases in perfusate calcium from 0.73 to 5.61 mmol/liter whereas uremic hearts failed in high calcium perfusate. Collection of 31P NMR spectra from hearts of renal failure and control animals during 30 min normoxic Langendorff perfusion showed that basal phosphocreatine was reduced by 32% to 4.7 mumol/g wet wt (P < 0.01) and the phosphocreatine to ATP ratio was reduced by 32% (P < 0.01) in uremic hearts. During low flow ischemia, there was a substantial decrease in phosphocreatine in the uremic hearts and an accompanying marked increase in release of inosine into the coronary effluent (14.9 vs 6.1 microM, P < 0.01). We conclude that cardiac function is impaired in experimental renal failure, in association with abnormal cardiac energetics and increased susceptibility to ischemic damage. Disordered myocardial calcium utilization may contribute to these derangements. PMID:8254048

Raine, A E; Seymour, A M; Roberts, A F; Radda, G K; Ledingham, J G

1993-01-01

348

Net cardiac shunts in anuran amphibians: physiology or physics?  

PubMed

Amphibians have a single ventricle and common conus arteriosus that produces an equal pressure to the parallel pulmocutaneous and systemic vascular circuits. The distribution of blood flows between the pulmocutaneous (Qpul) and systemic (Qsys) circuits (net cardiac shunt) varies with a number of environmental conditions and behaviours; although autonomic regulation of pulmonary vascular resistance conductance has been emphasized, little attention has been paid to the possible contribution of the passive physical characteristics of the two circuits to pressure changes associated with variation in cardiac output. In this study, we re-analysed three recent studies that recorded net cardiac shunts in the cane toad (Rhinella marina) under a variety of conditions and treatments. In all three studies, Qpul and Qsys were linearly related to cardiac output (Qtot), but the slope was threefold higher for Qpul compared with Qsys as predicted by relative conductance increases associated with increases in pressure from perfused preparations where autonomic regulation and humoral control were eliminated. Our analysis indicates that the net cardiac shunt in the cane toad is predicted primarily by the physical, rather than physiological, characteristics of the parallel pulmonary and systemic vascular circuits. PMID:24902743

Hillman, Stanley S; Hedrick, Michael S; Kohl, Zachary F

2014-08-15

349

Predictive value of the stomach wall pH for complications after cardiac operations: comparison with other monitoring  

Microsoft Academic Search

The ability to predict impending complications after elective cardiac operations from measurements of BP, cardiac index, arterial pH, and urine output on the day of operation was compared with that of indirect measurement of stomach wall pH in 85 patients. We found that acidosis in the stomach wall was the most sensitive predictor for complications. The specificity of this predictive

Richard G. Fiddian-Green; Stephen P. Baker

1987-01-01

350

Cardiac Safety Research Consortium: can the thorough QT/QTc study be replaced by early QT assessment in routine clinical pharmacology studies? Scientific update and a research proposal for a path forward.  

PubMed

The International Conference on Harmonization E14 guidance for the clinical evaluation of QT/QTc interval prolongation requires almost all new drugs to undergo a dedicated clinical study, primarily in healthy volunteers, the so-called TQT study. Since 2005, when the E14 guidance was implemented in United States and Europe, close to 400 TQT studies have been conducted. In February 2012, the Cardiac Safety Research Consortium held a think tank meeting at Food and Drug Administration's White Oak campus to discuss whether "QT assessment" can be performed as part of routine phase 1 studies. Based on these discussions, a group of experts convened to discuss how to improve the confidence in QT data from early clinical studies, for example, the First-Time-in-Human trial, through collection of serial electrocardiograms and pharmacokinetic samples and the use of exposure response analysis. Recommendations are given on how to design such "early electrocardiogram assessment," and the limitation of not having a pharmacologic-positive control in these studies is discussed. A research path is identified toward collecting evidence to replace or provide an alternative to the dedicated TQT study. PMID:25173536

Darpo, Borje; Garnett, Christine; Benson, Charles T; Keirns, James; Leishman, Derek; Malik, Marek; Mehrotra, Nitin; Prasad, Krishna; Riley, Steve; Rodriguez, Ignacio; Sager, Philip; Sarapa, Nenad; Wallis, Robert

2014-09-01

351

Cross sectional study of contribution of clinical assessment and simple cardiac investigations to diagnosis of left ventricular systolic dysfunction in patients admitted with acute dyspnoea.  

PubMed Central

OBJECTIVE: To assess the comparative contribution of clinical assessment, electrocardiography, and chest radiography to the diagnosis of left ventricular systolic dysfunction in patients admitted to a general medical ward with acute dyspnoea. DESIGN: Prospective cross sectional study. SETTING: Acute medical admissions ward of a teaching hospital. SUBJECTS: 71 randomly selected patients admitted with acute dyspnoea. MAIN OUTCOME MEASURES: Sensitivity and specificity of each investigation and logistic regression analysis of each variable in identifying left ventricular systolic dysfunction. RESULTS: Clinical assessment in this cohort of patients with severe dyspnoea was generally sensitive (sensitivity 81%). Patients were divided into three groups on the basis of clinical assessment. In the first group (37 patients) the diagnosis of systolic dysfunction was clear, in the second (22) it was in doubt, and in the third (12) it was unlikely. The sensitivity of clinical assessment in identifying left ventricular systolic dysfunction was 81% and the specificity was 47%. The specificity of diagnosis was improved by electrocardiography (69%) and chest radiography (92%). Logistic regression analysis showed that isolated pulmonary crepitations were a comparatively poor predictor of left ventricular systolic dysfunction chi 2 = 10.215, P = 0.0014) but that a full clinical examination had reasonable predictive value (chi 2 = 24.82, P < 0.00001). The combination of clinical assessment and chest radiography improved the accuracy of diagnosis (chi 2 = 28.08, P < 0.00001), as did the combination of clinical assessment and electrocardiography (chi 2 = 32.41, P < 0.00001). CONCLUSION: Clinical assessment in patients admitted with acute dyspnoea is comparatively accurate. Patients with abnormal results on chest radiography, electrocardiography, and clinical examination have a high likelihood of having left ventricular systolic dysfunction. Echocardiography contributes little more to the diagnosis in these patients and may be more efficiently directed towards patients in whom the diagnosis is still in doubt after clinical assessment, chest radiography, and electrocardiography. PMID:9099117

Gillespie, N. D.; McNeill, G.; Pringle, T.; Ogston, S.; Struthers, A. D.; Pringle, S. D.

1997-01-01

352

The effect of cardiac disease on hemoglobin-oxygen binding  

PubMed Central

The relation between degree of cardiac functional impairment and changes in hemoglobin-oxygen affinity and 2,3-diphosphoglycerate (2,3-DPG) has been studied in 39 patients with noncyanotic heart disease. A progressive decline in hemoglobin-oxygen affinity was found with worsening cardiac function as assessed by cardiac index, arteriovenous oxygen (A-V O2) difference, and cardiac symptoms; this alteration in hemoglobin-oxygen binding represents a significant mechanism for adaptation to the limited oxygen supply imposed by the cardiac lesion. The highly significant correlation of mixed venous blood oxygen saturation (S[unk]VVO2) with 2,3-DPG and the position of the oxygen dissociation curve suggests that the level of deoxygenated hemoglobin is an important in vivo regulator of hemoglobin-oxygen affinity. PMID:5432370

Woodson, R. D.; Torrance, J. D.; Shappell, S. D.; Lenfant, C.

1970-01-01

353

[Cardiac arrhythmia classification based on multi-features and support vector machines].  

PubMed

To solve the problem of cardiac arrhythmias classification, we proposed a novel algorithm based on the multi-feature fusion and support vector machines (SVM). Kernel independent component analysis (KICA) was used to extract nonlinear features and wavelet transform (WT) was used to extract time-frequency features. Combining these features could include more information about the disease. We designed the classification model based on SVM combined with error correcting output codes (ECOC). Receiver operating characteristic curve (ROC) and Area Under the ROC curve (AUC) value were used to assess the classification model. The value of AUC is 0.956 against MIT-BIH arrhythmia database. Experimental results showed effectiveness of the proposed method. PMID:21604488

Zhao, Yong; Hong, Wenxue; Sun, Shibo

2011-04-01

354

Beyond ultrasound: advances in multimodality cardiac imaging.  

PubMed

The rapid technological evolution accomplished in noninvasive cardiac imaging techniques over the past few decades has provided physicians with a large armamentarium for the evaluation of patients with known or suspected coronary heart disease. Noninvasive assessment of coronary artery calcium or noninvasive coronary angiography may be performed using computed tomography or magnetic resonance imaging. These techniques evaluate the presence of atherosclerosis rather than ischemia. Conversely, nuclear cardiology is the most widely used noninvasive approach for the assessment of myocardial perfusion and function. These techniques coupled with the development of dedicated image fusion software packages to merge data sets from different modalities have paved the way for hybrid imaging. This article provides a description of the available noninvasive imaging techniques in the assessment of coronary anatomy, myocardial perfusion, and cardiac function in patients with known or suspected coronary heart disease. PMID:25037458

Nappi, Carmela; Acampa, Wanda; Pellegrino, Teresa; Petretta, Mario; Cuocolo, Alberto

2015-02-01

355

Cardiovascular magnetic resonance in pregnancy: Insights from the cardiac hemodynamic imaging and remodeling in pregnancy (CHIRP) study  

PubMed Central

Background Cardiovascular disease in pregnancy is the leading cause of maternal mortality in North America. Although transthoracic echocardiography (TTE) is the most widely used imaging modality for the assessment of cardiovascular function during pregnancy, little is known on the role of cardiovascular magnetic resonance (CMR). The objective of the Cardiac Hemodynamic Imaging and Remodeling in Pregnancy (CHIRP) study was to compare TTE and CMR in the non-invasive assessment of maternal cardiac remodeling during the peripartum period. Methods Between 2010–2012, healthy pregnant women aged 18 to 35 years were prospectively enrolled. All women underwent TTE and CMR during the third trimester and at least 3 months postpartum (surrogate for non-pregnant state). Results The study population included a total of 34 women (mean age 29?±?3 years). During the third trimester, TTE and CMR demonstrated an increase in left ventricular end-diastolic volume from 95?±?11 mL to 115?±?14 mL and 98?±?6 mL to 125?±?5 mL, respectively (p?cardiac output, the values were consistently underestimated by TTE. Conclusion This CMR study provides reference values for cardiac indices during normal pregnancy and the postpartum state. PMID:24387349

2014-01-01

356

An individual patient meta-analysis of five randomized trials assessing the effects of cardiac resynchronization therapy on morbidity and mortality in patients with symptomatic heart failure  

PubMed Central

Aims Cardiac resynchronization therapy (CRT) with or without a defibrillator reduces morbidity and mortality in selected patients with heart failure (HF) but response can be variable. We sought to identify pre-implantation variables that predict the response to CRT in a meta-analysis using individual patient-data. Methods and results An individual patient meta-analysis of five randomized trials, funded by Medtronic, comparing CRT either with no active device or with a defibrillator was conducted, including the following baseline variables: age, sex, New York Heart Association class, aetiology, QRS morphology, QRS duration, left ventricular ejection fraction (LVEF), and systolic blood pressure. Outcomes were all-cause mortality and first hospitalization for HF or death. Of 3782 patients in sinus rhythm, median (inter-quartile range) age was 66 (58–73) years, QRS duration was 160 (146–176) ms, LVEF was 24 (20–28)%, and 78% had left bundle branch block. A multivariable model suggested that only QRS duration predicted the magnitude of the effect of CRT on outcomes. Further analysis produced estimated hazard ratios for the effect of CRT on all-cause mortality and on the composite of first hospitalization for HF or death that suggested increasing benefit with increasing QRS duration, the 95% confidence bounds excluding 1.0 at ?140 ms for each endpoint, suggesting a high probability of substantial benefit from CRT when QRS duration exceeds this value. Conclusion QRS duration is a powerful predictor of the effects of CRT on morbidity and mortality in patients with symptomatic HF and left ventricular systolic dysfunction who are in sinus rhythm. QRS morphology did not provide additional information about clinical response. ClinicalTrials.gov numbers NCT00170300, NCT00271154, NCT00251251. PMID:23900696

Cleland, John G.; Abraham, William T.; Linde, Cecilia; Gold, Michael R.; Young, James B.; Claude Daubert, J.; Sherfesee, Lou; Wells, George A.; Tang, Anthony S.L.

2013-01-01

357

Relation between N-terminal pro-brain natriuretic Peptide and cardiac remodeling and function assessed by cardiovascular magnetic resonance imaging in patients with arrhythmogenic right ventricular cardiomyopathy.  

PubMed

Although N-terminal pro-brain natriuretic peptide (NT-proBNP) is a useful screening test of impaired right ventricular (RV) function in conditions affecting the right-sided cardiac muscle, the role of NT-proBNP remains unclear in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). This study was designed to clarify the relation between the plasma NT-proBNP level and the RV function evaluated by cardiovascular magnetic resonance (CMR) imaging. We selected 56 patients with confirmed ARVC only when their blood specimens for NT-proBNP measurements were collected within 48 hours of a CMR scan. The NT-proBNP level was significantly higher in patients with RV dysfunction than in patients without RV dysfunction (median of 655.3 [interquartile range 556.4 to 870.0] vs 347.0 [interquartile range 308.0 to 456.2] pmol/L, p <0.001). The NT-proBNP levels were positively correlated with RV end-diastolic and end-systolic volume indices (r = 0.49 and 0.70, respectively) and negatively correlated with RV ejection fraction (r = -0.76, all p <0.001), which remained significant after adjustment for age, gender, and body mass index. The area under the receiver-operating characteristic curve for NT-proBNP was 0.91 (95% confidence interval 0.80 to 0.97, p <0.001). The cut-off value of NT-proBNP (458 pmol/L) was associated with sensitivity, specificity, and positive and negative predictive values of 91%, 89%, 67%, and 98%, respectively. In conclusion, NT-proBNP is a useful marker for the detection of RV dysfunction and associated with extent of RV dilatation and dysfunction determined by CMR in patients with ARVC. PMID:25523952

Cheng, Huaibing; Lu, Minjie; Hou, Cuihong; Chen, Xuhua; Wang, Jing; Yin, Gang; Chu, Jianmin; Zhang, Shu; Prasad, Sanjay K; Pu, Jielin; Zhao, Shihua

2015-02-01

358

Health Risk Assessment for Air Pollutants: Alterations in Lung and Cardiac Gene Expression in Mice Exposed to Milano Winter Fine Particulate Matter (PM2.5)  

PubMed Central

Oxidative stress, pulmonary and systemic inflammation, endothelial cell dysfunction, atherosclerosis and cardiac autonomic dysfunction have been linked to urban particulate matter exposure. The chemical composition of airborne pollutants in Milano is similar to those of other European cities though with a higher PM2.5 fraction. Milano winter fine particles (PM2.5win) are characterized by the presence of nitrate, organic carbon fraction, with high amount of polycyclic aromatic hydrocarbons and elements such as Pb, Al, Zn, V, Fe, Cr and others, with a negligible endotoxin presence. In BALB/c mice, we examined, at biochemical and transcriptomic levels, the adverse effects of repeated Milano PM2.5win exposure in lung and heart. We found that ET-1, Hsp70, Cyp1A1, Cyp1B1 and Hsp-70, HO-1, MPO respectively increased within lung and heart of PM2.5win-treated mice. The PM2.5win exposure had a strong impact on global gene expression of heart tissue (181 up-regulated and 178 down-regulated genes) but a lesser impact on lung tissue (14 up-regulated genes and 43 down-regulated genes). Focusing on modulated genes, in lung we found two- to three-fold changes of those genes related to polycyclic aromatic hydrocarbons exposure and calcium signalling. Within heart the most striking aspect is the twofold to threefold increase in collagen and laminin related genes as well as in genes involved in calcium signaling. The current study extends our previous findings, showing that repeated instillations of PM2.5win trigger systemic adverse effects. PM2.5win thus likely poses an acute threat primarily to susceptible people, such as the elderly and those with unrecognized coronary artery or structural heart disease. The study of genomic responses will improve understanding of disease mechanisms and enable future clinical testing of interventions against the toxic effects of air pollutant. PMID:25296036

Battaglia, Cristina; Cifola, Ingrid; Mangano, Eleonora; Mantecca, Paride; Camatini, Marina; Palestini, Paola

2014-01-01

359

False cardiac arrests: the right time to turn away?  

PubMed Central

Aim Cardiac arrest teams may be activated only to find that the patient does not require cardiac or respiratory resuscitation. Members of the cardiac arrest team are drawn from medical personnel with other responsibilities who may disperse quickly, leaving ongoing care of the patient to existing ward staff. The outcome for such false cardiac arrests, however, is rarely reported. The objective of this study was to determine the causes of false cardiac arrest team alerts (FCAs) and to assess the outcome of these patients relative to the general hospital population. Setting Tertiary care hospital. Participants Patients subject to a cardiac arrest call who were found not to require basic or advanced cardiac life support on arrival. Results In 512 events over a 1?year period, patients suffering FCAs were more likely to survive compared to patients suffering cardiac arrest (15% vs 73%, odds ratio (OR) 14.95; ?2 p?0.0001), but significantly less likely to survive than the general hospitalised population (73% vs 97%, OR 14.15; ?2 p?0.0001). The cause of the FCA was often minimised as collapse or vasovagal syncope; in 58% (87/150) of cases no further action was taken by the attending medical team. Patients suffering FCAs tended to be long?stay patients with a worse outcome at weekends. Conclusion In areas lacking a medical alert, outreach or patient at risk system, particular attention should be paid to optimising care of those suffering FCAs. PMID:17488866

Kenward, Gary; Robinson, Alan; Bradburn, Sandra; Steeds, Richard

2007-01-01

360

Haemodynamic responses to stimulation of the cardiac autonomic nerves in the anaesthetized cat with closed chest  

PubMed Central

1. The changes in cardiac output and mean right atrial pressure (R.A.P.) evoked by stimulation of the cardiac autonomic nerves were investigated in cats under chloralose anaesthesia, with unopened chests and spontaneous respiration, and with active vascular reflexes. Cardiac output was measured by thermal dilution; the technique used was calibrated against the direct Fick method. 2. The initial values of R.A.P. and output were varied by infusion of dextran-saline solution followed by withdrawal of blood. At positive values of R.A.P. withdrawal of blood caused a fall in R.A.P. with no change in cardiac output. At negative R.A.P. blood withdrawal caused a fall in output with little change in R.A.P.: the linear regression coefficient for output on R.A.P. was 48·2 ml./min.kg.mmHg (S.E. 2·06, n = 63, nine cats). 3. Stimulation of the right cardiac sympathetic nerve increased heart rate by 69·2 beats/min (S.E. 4·0) from the resting rate of 158 beats/min (S.E. 6·3, ten cats). The acceleration was accompanied in most instances by a rise in cardiac output and a fall in R.A.P. and the magnitude of the rise in output was related to that of the fall in R.A.P. 4. In no experiment could R.A.P. be reduced below -2·5 mmHg either by withdrawal of blood or by sympathetic stimulation. At negative values of R.A.P. the fall in R.A.P. and rise in output evoked by sympathetic stimulation were small; substantial changes could be obtained only from positive initial values of R.A.P. The proportional increase in output evoked by a given proportional increase in heart rate during near-maximal sympathetic stimulation had a linear relationship to the initial value of R.A.P. over the range -2 to +8 mmHg. The output increment was less than proportional to the rate increment at all values of R.A.P. below +3 mmHg. 5. In five experiments stimulation of the left cardiac sympathetic nerve evoked a greater increase in output for a given increase in heart rate than did stimulation of the right nerve; on the other hand both nerves gave similar increments of output for a given fall in R.A.P. 6. Stimulation of the distal end of the right vagus nerve slowed the heart and caused a fall in cardiac output and a rise in R.A.P. The change in output associated with a given change in R.A.P. was significantly greater (P = 0·05) during sympathetic than during vagal stimulation in 14 out of 18 tests; the difference increased as circulating volume was reduced. 7. It is concluded that the relationship between cardiac output and R.A.P. during sympathetic and vagal stimulation is consistent with the hypothesis that neurally evoked changes in cardiac performance vary output mainly, but not exclusively, by inducing changes in R.A.P. which alter the pressure gradient for the return of blood to the right atrium from the periphery. PMID:7381778

Barnes, R. J.; Bower, E. A.; Rink, T. J.

1980-01-01

361

Cardiac radiology: centenary review.  

PubMed

During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day. PMID:25340434

de Roos, Albert; Higgins, Charles B

2014-11-01

362

Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients  

Microsoft Academic Search

Objective: To assess risk factors for mortality in cardiac surgical adult patients as part of a study to develop a European System for Cardiac Operative Risk Evaluation (EuroSCORE). Methods: From September to November 1995, information on risk factors and mortality was collected for 19030 consecutive adult patients undergoing cardiac surgery under cardiopulmonary bypass in 128 surgical centres in eight European

F. Roques; S. A. M. Nashef; P. Michel; E. Gauducheau; C. de Vincentiis; E. Baudet; J. Cortina; M. David; A. Faichney; F. Gavrielle; E. Gams; A. Harjula; M. T. Jones; P. Pinna Pintor; R. Salamon; L. Thulin

1999-01-01

363

The repeated sit-to-stand maneuver is a superior method for cardiac baroreflex assessment: a comparison with the modified Oxford method and Valsalva maneuver.  

PubMed

Baroreflex assessment has diagnostic and prognostic utility in the clinical and research environments, and there is a need for a reliable, simple, noninvasive method of assessment. The repeated sit-to-stand method induces oscillatory changes in blood pressure (BP) at a desired frequency and is suitable for assessing dynamic baroreflex sensitivity (BRS). However, little is known about the reliability of this method and its ability to discern fundamental properties of the baroreflex. In this study we sought to: 1) evaluate the reliability of the sit-to-stand method for assessing BRS and compare its performance against two established methods (Oxford method and Valsalva maneuver), and 2) examine whether the frequency of the sit-to-stand method influences hysteresis. Sixteen healthy participants underwent three trials of each method. For the sit-to-stand method, which was performed at 0.1 and 0.05 Hz, BRS was quantified as an integrated response (BRSINT) and in response to falling and rising BP (BRSDOWN and BRSUP, respectively). Test retest reliability was assessed using the intraclass correlation coefficient (ICC). Irrespective of frequency, the ICC for BRSINT during the sit-to-stand method was ?0.88. The ICC for a rising BP evoked by phenylephrine (PEGAIN) in the Oxford method was 0.78 and ?0.5 for the remaining measures. During the sit-to-stand method, hysteresis was apparent in all participants at 0.1 Hz but was absent at 0.05 Hz. These findings indicate the sit-to-stand method is a statistically reliable BRS assessment tool and suitable for the examination of baroreflex hysteresis. Using this approach we showed that baroreflex hysteresis is a frequency-dependent phenomenon. PMID:25274908

Horsman, H M; Tzeng, Y C; Galletly, D C; Peebles, K C

2014-12-01

364

Influence of gravity on cardiac performance.  

PubMed

Results obtained by the investigators in ground-based experiments and in two parabolic flight series of tests aboard the NASA KC-135 aircraft with a hydraulic simulator of the human systemic circulation have confirmed that a simple lack of hydrostatic pressure within an artificial ventricle causes a decrease in stroke volume of 20%-50%. A corresponding drop in stroke volume (SV) and cardiac output (CO) was observed over a range of atrial pressures (AP), representing a rightward shift of the classic CO versus AP cardiac function curve. These results are in agreement with echocardiographic experiments performed on space shuttle flights, where an average decrease in SV of 15% was measured following a three-day period of adaptation to weightlessness. The similarity of behavior of the hydraulic model to the human system suggests that the simple physical effects of the lack of hydrostatic pressure may be an important mechanism for the observed changes in cardiac performance in astronauts during the weightlessness of space flight. PMID:9846932

Pantalos, G M; Sharp, M K; Woodruff, S J; O'Leary, D S; Lorange, R; Everett, S D; Bennett, T E; Shurfranz, T

1998-01-01

365

Effects of intracoronary and intravenous amrinone infusions in patients with cardiac failure and patients with near normal cardiac function.  

PubMed Central

The effects of intracoronary and intravenous infusions of amrinone were studied to distinguish the drug's direct cardiac actions from its peripheral vascular and neuroendocrine properties. Intracoronary infusions of amrinone were found to have no haemodynamic effect other than producing a slight reduction in the left ventricular ejection fraction and some suggestion of coronary vasodilatation in patients with impaired left ventricular function. They did not improve contractility, cardiac output, or filling pressures and had no significant effect on myocardial metabolism, although therapeutic concentrations of the drug were detected in coronary sinus blood. Intravenously administered amrinone reduced filling pressures and improved the cardiac index in all patients, but haemodynamic improvements were most pronounced in the patients with the worst cardiac function. These changes were accompanied by improvements in the indices of contractility only in patients in whom alterations in concentrations of free fatty acid, glycerol, and glucose suggested peripheral catecholamine release. In the patients with the best basal cardiac function intravenously administered amrinone produced a reduction in myocardial work and evidence of myocardial ischaemia, as a result of excessive reduction of coronary perfusion pressure and increased heart rate, without any appreciable increase in cardiac index. It is concluded that, at the concentrations of the drug that can be achieved in man without adverse effects, amrinone has no direct positive inotropic effect. Haemodynamic changes are predominantly the result of vasodilatation, although catecholamines may be released in some patients. PMID:3994862

Wilmshurst, P T; Thompson, D S; Juul, S M; Dittrich, H C; Dawson, J R; Walker, J M; Jenkins, B S; Coltart, D J; Webb-Peploe, M M

1985-01-01

366

Acoustic output measured by thermal and mechanical indices during fetal echocardiography at the time of the first trimester scan.  

PubMed

We measured acoustic output, expressed as the thermal index (TI) and mechanical index (MI), during fetal echocardiography at the time of the first trimester scan. TI and MI were retrieved from the saved displays during gray-mode, high-definition color flow Doppler and pulsed-wave Doppler (tricuspid flow) ultrasound examinations of the fetal heart and from the ductus venosus assessment. A total of 399 fetal cardiac examinations were evaluated. There was a significant increase in TI values from B-mode studies (0.07 ± 0.04 [mean ± SD]) to color flow mapping (0.2 ± 0.0) and pulsed-wave Doppler studies (0.36 ± 0.05). The TI from ductus venosus assessment (0.1 ± 0.01) was significantly lower than those from Doppler examinations of the heart. MI values from B-mode scans (0.65 ± 0.12) and color flow mapping (0.71 ± 0.11) were comparable, although different, and both values were higher than those from pulsed-wave Doppler tricuspid evaluation (0.39 ± 0.03). There were no differences in MI values from power Doppler assessment between the tricuspid flow and ductus venosus. Safety indices were remarkably stable and were largely constant, especially for color Doppler (TI), tricuspid flow (MI) and ductus venosus assessment (TI, MI). We acquired satisfactory Doppler images and/or signals at acoustic levels that were lower than the actual recommendations and never reached a TI of 0.5. PMID:25438839

Nemescu, Dragos; Berescu, Anca

2015-01-01

367

Cardiac transthyretin amyloidosis.  

PubMed

Cardiac amyloidosis of transthyretin fibril protein (ATTR) type is an infiltrative cardiomyopathy characterised by ventricular wall thickening and diastolic heart failure. Increased access to cardiovascular magnetic resonance imaging has led to a marked increase in referrals to our centre of Caucasian patients with wild-type ATTR (senile systemic) amyloidosis and Afro-Caribbean patients with the hereditary ATTR V122I type. Both subtypes present predominantly as isolated cardiomyopathy. The differential diagnosis includes cardiac amyloid light-chain (AL) amyloidosis, which has a poorer prognosis and can be amenable to chemotherapy. We review here the clinical features of cardiac ATTR amyloidosis and describe the diagnostic tests to determine ATTR type. Correct diagnosis is ever more crucial given that several novel therapies for ATTR amyloidosis are on the near horizon. PMID:22888163

Dungu, Jason N; Anderson, Lisa J; Whelan, Carol J; Hawkins, Philip N

2012-11-01

368

A New Frontier for Cardiac Monitoring  

NASA Technical Reports Server (NTRS)

CardioDynamics International Corporation (CDIC) has created the BioZ(TM) System through a Small Business Innovation Research (SBIR) award from Johnson Space Center, providing patients and physicians with a cost-effective and highly accurate monitoring system.The BioZ non-invasive heart monitor is based on a technology known as Impedance Cardiography (ICG). BioZ provides the physician with vital information about the heart's ability to deliver blood to the body, the force one's heart exerts with each beat, and the amount of fluid in the chest. Specially designed bioimpedance sensors placed on the neck and chest monitor 12 different parameters, including cardiac output, contractility, systemic vascular resistance, and thoracic fluid content. These sensors monitor the electrical conductivity of the body-information that is converted into blood flow data and is displayed in real time on a monitoring screen. BioZ.com(TM) and BioZ.pc(TM) are two additional products that incorporate the same sensors present in the original BioZ system. The "com" in BioZ.com stands for cardiac output monitor. This fully integrated system is essentially a smaller version of the BioZ, combining the same abilities with a compact, lightweight design, while providing greater portability.

2001-01-01

369

Cardiac Tumors: A Brief Commentary  

PubMed Central

Patients with cardiac tumors may present with cardiovascular related or constitutional symptoms, but more often than not a cardiac mass is discovered incidentally during an imaging examination performed for an unrelated indication. Cardiac myxoma is generally considered to be a surgical emergency. Echocardiography, including the transesophageal approach, is the most important means of diagnosis; computed tomography and magnetic resonance imaging. The clinical presentation has changed, and the management of cardiac myxoma now needs to be reviewed.

Roever, Leonardo; Casella-Filho, Antonio; Dourado, Paulo Magno Martins; Resende, Elmiro Santos; Chagas, Antônio Carlos Palandri

2014-01-01

370

Emergency Cardiac Care: An Update  

PubMed Central

The authors review the new guidelines for basic life support and advanced cardiac life support and the recommended changes to the standards. The changes recommended for basic life support will simplify the psychomotor skills required. The recommended changes to the guidelines for advanced cardiac life support, which include discontinuing the use of isoproterenol and limiting the use of sodium bicarbonate in cardiac arrest, are likely to improve survival rates. Controversies in the management of cardiac arrest are also discussed. PMID:21253157

Swanson, Richard W.

1988-01-01

371

Radiation dose of cardiac CT—what is the evidence?  

Microsoft Academic Search

Current evidence and most pertinent literature on the radiation dose of cardiac computed tomography (CT) for the noninvasive\\u000a assessment of coronary artery disease are reviewed. The various means for adjusting CT protocols to lower the radiation to\\u000a a level that is as low as reasonably achievable are discussed. It is shown that for the target population of cardiac CT, the

Hatem Alkadhi

2009-01-01

372

Specific changes in skeletal muscle myosin heavy chain composition in cardiac failure: differences compared with disuse atrophy as assessed on microbiopsies by high resolution electrophoresis.  

PubMed Central

OBJECTIVE: In congestive heart failure (CHF) the skeletal muscle of the lower limbs develops a myopathy with atrophy and shift from the slow type to the fast type fibres. The aim was to test the hypothesis that this myopathy is specific and not simply related to detraining, by comparing patients with different degrees of CHF with patients with severe muscle atrophy due to disuse. DESIGN: Case-control study involving 50-150 micrograms needle biopsies of the gastrocnemius muscle. By an electrophoretic micromethod, the three isoforms of myosin heavy chains (MHC) were separated. PATIENTS: Five patients restricted to bed for more than one year because of stroke with disuse atrophy and normal ventricular function, and 19 with CHF were studied. There were seven age matched controls. MAIN OUTCOME MEASURES: The percentage of MHC1 (slow isoform), MHC2a (fast oxidative), and MHC2b (fast glycolytic) was determined by densitometric scan and correlated with indices of severity of cardiac failure. RESULTS: Ejection fraction was 42.5 (SD 15.2)% in CHF, 59.5 (1.0)% in disuse atrophy and 60.3 (1.4)% in controls (P < 0.001 v both). The degree of muscle atrophy as calculated by the body mass index/gastrocnemius cross sectional area, showed a profound degree of atrophy in patients with muscle disuse [0.94 (0.39)]. This was worse than in the controls [4.27 (0.16), P < 0.0005] and the CHF patients [2.60 (1.10), P < 0.005]. Atrophy in CHF patients was also greater than in controls (P < 0.005). MHC1 was lower in CHF than in disuse atrophy [51.83 (15.04) v 84.5 (17.04), P < 0.01] while MHC2b was higher [23.5 (7.4) v 7.25 (7.92), P < 0.001]. There was a similar trend for MHC2a [24.83 (15.01) v 8.25 (9.12), P < 0.05]. Within the CHF group there was a positive correlation between NYHA class and MHC2a (r = 0.47, P < 0.05) and MHC2b (r = 0.55, P < 0.01) and a negative correlation between NYHA class and MHC1 (r = -0.74, P < 0.001). Similarly, significant correlations were found for ejection fraction, diuretic consumption score, exercise test tolerance, and degree of muscle atrophy. CONCLUSIONS: The CHF myopathy appears to be specific and not related to detraining. The magnitude of MCH redistribution correlates with the severity of the disease. The electrophoretic micromethod used is very sensitive and reproducible. Biopsies are so well tolerated that can be repeated frequently, allowing thorough follow up. Images PMID:8983681

Vescovo, G.; Serafini, F.; Facchin, L.; Tenderini, P.; Carraro, U.; Dalla Libera, L.; Catani, C.; Ambrosio, G. B.

1996-01-01

373

Validation of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in North American cardiac surgery  

Microsoft Academic Search

Objective: To assess the performance of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) when applied in a North American cardiac surgical population. Methods: The simple additive EuroSCORE model was applied to predict operative mortality (in-hospital or 30-day) in 401?684 patients undergoing coronary or valve surgery in 1998 and 1999 as well as in 188?913 patients undergoing surgery in

Samer A. M Nashef; Francois Roques; Bradley G Hammill; Eric D Peterson; Philippe Michel; Frederick L Grover; Richard K. H Wyse; T. Bruce Ferguson

2002-01-01

374

Validation of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in North American cardiac surgeryq  

Microsoft Academic Search

Objective: To assess the performance of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) when applied in a North American cardiac surgical population. Methods: The simple additive EuroSCORE model was applied to predict operative mortality (in-hospital or 30-day) in 401 684 patients undergoing coronary or valve surgery in 1998 and 1999 as well as in 188 913 patients undergoing

Samer A. M. Nashefa; Francois Roquesb; Bradley G. Hammillc; Eric D. Petersonc; Philippe Micheld; Frederick L. Grovere; Richard K. H. Wysee; T. Bruce Fergusone

375

Impact of obesity and weight loss on cardiac performance and morphology in adults.  

PubMed

Obesity, particularly severe obesity is capable of producing hemodynamic alterations that predispose to changes in cardiac morphology and ventricular function. These include increased cardiac output, left ventricular hypertrophy and diastolic and systolic dysfunction of both ventricles. Facilitated by co-morbidities such as hypertension, the sleep apnea/obesity hypoventilation syndrome, and possibly certain neurohormonal and metabolic alterations, these abnormalities may predispose to left and right heart failure, a disorder known as obesity cardiomyopathy. PMID:24438730

Alpert, Martin A; Omran, Jad; Mehra, Ankit; Ardhanari, Sivakumar

2014-01-01

376

Acute Alcohol Modulates Cardiac Function as PI3K/Akt Regulates Oxidative Stress  

PubMed Central

Background Clinical manifestations of alcohol abuse on the cardiac muscle include defective contractility with the development of heart failure. Interestingly, low alcohol consumption has been associated with reduced risk of cardiovascular disease. Although several hypotheses have been postulated for alcoholic cardiomyopathy and for the low-dose beneficial cardiovascular effects, the precise mechanisms and mediators remain largely undefined. We hypothesize that modulation of oxidative stress by PI3K/Akt plays a key role in the cardiac functional outcome to acute alcohol exposure. Methods Thus, acutely exposed rat cardiac tissue and cardiocytes to low (LA: 5 mM), moderate (MA: 25 mM), and high (HA: 100 mM) alcohol were assessed for markers of oxidative stress in the presence and absence of PI3K/Akt activators (IGF-1 0.1 ?M or constitutively active PI3K: Ad.BD110 transfection) or inhibitor (LY294002 1 ?Mor Akt-negative construct Ad.Akt(K179M) transfection). Results Acute LA reduced Akt, superoxide dismutase (SOD-3) and NF?B, ERK1, and p38 MAPK gene expression. Acute HA only increased that of SOD-3 and NF?B. These effects were generally inhibited by Ad.Akt(K179M) and enhanced with Ad.BD110 transfection. In parallel, LA reduced but HA enhanced Akt activity, which was reversed by IGF-1 and inhibited by Ad.Akt(K179M), respectively. Also, LA reduced caspase 3/7 activity and oxidative stress, while HA increased both. The former was blocked, while the latter effect was enhanced by Ad.Akt(K179M). The reverse was true with PI3K/Akt activation. This translated into reduced viability with HA, with no effect with LA. On the functional level, acute LA improved cardiac output and ejection fraction, mainly through increased stroke volume. This was accompanied with enhanced end-systolic pressure–volume relationship and preload recruitable stroke work. Opposite effect was recorded for HA. LA and HA in vivo functional effects were alleviated by LY and enhanced by IGF-1 treatment. Conclusions Acute LA and HA seem to oppositely affect cardiac function through modulation of oxidative stress where PI3K/Akt plays a pivotal role. PMID:24962888

Umoh, Nsini A.; Walker, Robin K.; Al-Rubaiee, Mustafa; Jeffress, Miara A.; Haddad, Georges E.

2015-01-01

377

Melatonin and cardiac pathophysiology  

Microsoft Academic Search

Melatonin, an indole produced in several organs but most notably in the pineal gland, has a variety of effects that influence cardiac pathophysiology. Herein, we summarize the findings that illustrate the ability of melatonin to attenuate the severity of hypertension, limit myocardial damage, improve the function of the ischemic-reperfused heart, protect the heart from the toxicity of anthracycline drugs and

Russel J. Reiter; Dun X. Tan

378

Fetal cardiac anomalies  

Microsoft Academic Search

Fetal cardiac anomalies are increasingly identified during regular obstetric scanning. About 21000 pregnancies will have an abnormality of the four chamber view and a further 11000 will have an abnormality of the great arteries. These cases can then be referred to the specialist in fetal cardiology for further evaluation and counselling. There is a higher rate of chromosomal and other

Lindsey D. Allan

1996-01-01

379

Cardiac fibroma in adults.  

PubMed

We present the case of a 61-year-old woman with nonspecific symptoms who on investigation and treatment had a fibroma of the right ventricular free wall. She underwent surgical resection of the mass and is doing well. The literature pertaining to cardiac fibromas in adults is reviewed and discussed. PMID:20934889

Nwachukwu, Harriet; Li, Alice; Nair, Vidhya; Nguyen, Elsie; David, Tirone E; Butany, Jagdish

2011-01-01

380

Cardiac function monitoring system  

Microsoft Academic Search

An IBM-PC controlled system has been developed to evaluate the cardiac function in the catheterization room. The system uses a multielectrode impedancimetric catheter to compute the instantaneous left intraventricular heart volume, through specially developed algorithms and calibration procedures, and a catheter tip micromanometer to measure the instantaneous left intraventricular pressure. With these two variables, and after a preload maneuver, the

J. C. Spinelli; M. C. Herrera

1988-01-01

381

Single breath-hold assessment of cardiac function using an accelerated 3D single breath-hold acquisition technique - comparison of an intravascular and extravascular contrast agent  

PubMed Central

Background Cardiovascular magnetic resonance (CMR) is the current gold standard for the assessment of left ventricular (LV) function. Repeated breath-holds are needed for standard multi-slice 2D cine steady-state free precession sequences (M2D-SSFP). Accelerated single breath-hold techniques suffer from low contrast between blood pool and myocardium. In this study an intravascular contrast agent was prospectively compared to an extravascular contrast agent for the assessment of LV function using a single-breath-hold 3D-whole-heart cine SSFP sequence (3D-SSFP). Methods LV function was assessed in fourteen patients on a 1.5?T MR-scanner (Philips Healthcare) using 32-channel coil technology. Patients were investigated twice using a 3D-SSFP sequence (acquisition time 18–25?s) after Gadopentetate dimeglumine (GdD, day 1) and Gadofosveset trisodium (GdT, day 2) administration. Image acquisition was accelerated using sensitivity encoding in both phase encoding directions (4xSENSE). CNR and BMC were both measured between blood and myocardium. The CNR incorporated noise measurements, while the BMC represented the coeffiancy between the signal from blood and myocardium [1]. Contrast to noise ratio (CNR), blood to myocardium contrast (BMC), image quality, LV functional parameters and intra-/interobserver variability were compared. A M2D-SSFP sequence was used as a reference standard on both days. Results All 3D-SSFP sequences were successfully acquired within one breath-hold after GdD and GdT administration. CNR and BMC were significantly (p?assessment of LV function. Trial registration The study was approved by the local research ethics committee (Study No. 07/Q0704/2) and was registered with the Medicines and Healthcare Products Regulatory Agency (MHRA Study No. 28482/0002/001–0001, EudraCTnumber 2006–007042). PMID:22849703

2012-01-01

382

Utilization of the Organ Care System Lung for the assessment of lungs from a donor after cardiac death (DCD) before bilateral transplantation.  

PubMed

In this manuscript, we present the first experience of evaluating donation after circulatory death (DCD) lungs, using the normothermic preservation Organ Care System (OCS) and subsequent successful transplantation. The OCS could be a useful tool for the evaluation of marginal lungs from DCD donors as it allows a proper recruitment and bronchoscopy in such donations in addition to continuous ex-vivo perfusion and assessment and treatment during transport. The OCS could potentially be a standard of care in the evaluation of marginal lungs from DCD. PMID:25332197

Mohite, Pn; Sabashnikov, A; García Sáez, D; Pates, B; Zeriouh, M; De Robertis, F; Simon, Ar

2014-10-20