Accurate, noninvasive continuous monitoring of cardiac output by whole-body electrical bioimpedance.

PubMed

Cotter, Gad; Moshkovitz, Yaron; Kaluski, Edo; Cohen, Amram J; Miller, Hilton; Goor, Daniel; Vered, Zvi

2004-04-01

Cardiac output (CO) is measured but sparingly due to limitations in its measurement technique (ie, right-heart catheterization). Yet, in recent years it has been suggested that CO may be of value in the diagnosis, risk stratification, and treatment titration of cardiac patients, especially those with congestive heart failure (CHF). We examine the use of a new noninvasive, continuous whole-body bioimpedance system (NICaS; NI Medical; Hod-Hasharon, Israel) for measuring CO. The aim of the present study was to test the validity of this noninvasive cardiac output system/monitor (NICO) in a cohort of cardiac patients. Prospective, double-blind comparison of the NICO and thermodilution CO determinations. We enrolled 122 patients in three different groups: during cardiac catheterization (n = 40); before, during, and after coronary bypass surgery (n = 51); and while being treated for acute congestive heart failure (CHF) exacerbation (n = 31). MEASUREMENTS AND INTERVENTION: In all patients, CO measurements were obtained by two independent blinded operators. CO was measured by both techniques three times, and an average was determined for each time point. CO was measured at one time point in patients undergoing coronary catheterization; before, during, and after bypass surgery in patients undergoing coronary bypass surgery; and before and during vasodilator treatment in patients treated for acute heart failure. Overall, 418 paired CO measurements were obtained. The overall correlation between the NICO cardiac index (CI) and the thermodilution CI was r = 0.886, with a small bias (0.0009 +/- 0.684 L) [mean +/- 2 SD], and this finding was consistent within each group of patients. Thermodilution readings were 15% higher than NICO when CI was < 1.5 L/min/m(2), and 5% lower than NICO when CI was > 3 L/min/m(2). The NICO has also accurately detected CI changes during coronary bypass operation and vasodilator administration for acute CHF. The results of the present study indicate

Validation of cardiac output studies from the Mostcare compared to a pulmonary artery catheter in septic patients.

PubMed

Gopal, S; Do, T; Pooni, J S; Martinelli, G

2014-03-01

The Mostcare monitor is a non-invasive cardiac output monitor. It has been well validated in cardiac surgical patients but there is limited evidence on its use in patients with severe sepsis and septic shock. The study included the first 22 consecutive patients with severe sepsis and septic shock in whom the floatation of a pulmonary artery catheter was deemed necessary to guide clinical management. Cardiac output measurements including cardiac output, cardiac index and stroke volume were simultaneously calculated and recorded from a thermodilution pulmonary artery catheter and from the Mostcare monitor respectively. The two methods of measuring cardiac output were compared by Bland-Altman statistics and linear regression analysis. A percentage error of less than 30% was defined as acceptable for this study. Bland-Altman analysis for cardiac output showed a Bias of 0.31 L.min-1, precision (=SD) of 1.97 L.min-1 and a percentage error of 62.54%. For Cardiac Index the bias was 0.21 L.min-1.m-2, precision of 1.10 L.min-1.m-2 and a percentage error of 64%. For stroke volume the bias was 5 mL, precision of 24.46 mL and percentage error of 70.21%. Linear regression produced a correlation coefficient r2 for cardiac output, cardiac index, and stroke volume, of 0.403, 0.306, and 0.3 respectively. Compared to thermodilution cardiac output, cardiac output studies obtained from the Mostcare monitor have an unacceptably high error rate. The Mostcare monitor demonstrated to be an unreliable monitoring device to measure cardiac output in patients with severe sepsis and septic shock on an intensive care unit.

Thromboresistant surface coatings for the measurement of cardiac output through continuous low flow peripheral A-V shunts.

PubMed Central

Deeb, G M; Borovetz, H S; Griffith, B P; Hardesty, R L

1980-01-01

The dilution technique for determining cardiac output using indocyanine green dye is limited in patients weighing less than 20 kg because of the obligatory volume loss. Reproducible achieved using the green dye dilution method by the establishment of a low flow peripheral arteriovenous shunt. The shunt materials were treated with thromboresistant agents--TDMAC (7%) and albumin (1 g/dl)--to facilitate the use of this technique without heparin. For A-V shunt flow rates of 8-30 cc/min reproducible values of cardiac output were obtained for up to 38 hours which were in good agreement with determinations made using the conventional technique of dye dilution. PMID:6986120

Pulse Wave Transit Time Measurements of Cardiac Output in Septic Shock Patients: A Comparison of the Estimated Continuous Cardiac Output System with Transthoracic Echocardiography.

PubMed

Feissel, Marc; Aho, Ludwig Serge; Georgiev, Stefan; Tapponnier, Romain; Badie, Julio; Bruyère, Rémi; Quenot, Jean-Pierre

2015-01-01

We determined reliability of cardiac output (CO) measured by pulse wave transit time cardiac output system (esCCO system; COesCCO) vs transthoracic echocardiography (COTTE) in mechanically ventilated patients in the early phase of septic shock. A secondary objective was to assess ability of esCCO to detect change in CO after fluid infusion. Mechanically ventilated patients admitted to the ICU, aged >18 years, in sinus rhythm, in the early phase of septic shock were prospectively included. We performed fluid infusion of 500 ml of crystalloid solution over 20 minutes and recorded CO by EsCCO and TTE immediately before (T0) and 5 minutes after (T1) fluid administration. Patients were divided into 2 groups (responders and non-responders) according to a threshold of 15% increase in COTTE in response to volume expansion. In total, 25 patients were included, average 64±15 years, 15 (60%) were men. Average SAPSII and SOFA scores were 55±21.3 and 13±2, respectively. ICU mortality was 36%. Mean cardiac output at T0 was 5.8±1.35 L/min by esCCO and 5.27±1.17 L/min by COTTE. At T1, respective values were 6.63 ± 1.57 L/min for esCCO and 6.10±1.29 L/min for COTTE. Overall, 12 patients were classified as responders, 13 as non-responders by the reference method. A threshold of 11% increase in COesCCO was found to discriminate responders from non-responders with a sensitivity of 83% (95% CI, 0.52-0.98) and a specificity of 77% (95% CI, 0.46-0.95). We show strong correlation esCCO and echocardiography for measuring CO, and change in CO after fluid infusion in ICU patients.

Immediate increase of cardiac output after percutaneous mitral valve repair (PMVR) determined by echocardiographic and invasive parameters: Patzelt: Increase of cardiac output after PMVR.

PubMed

Patzelt, Johannes; Zhang, Yingying; Magunia, Harry; Jorbenadze, Rezo; Droppa, Michal; Ulrich, Miriam; Cai, Shanglang; Lausberg, Henning; Walker, Tobias; Wengenmayer, Tobias; Rosenberger, Peter; Schreieck, Juergen; Seizer, Peter; Gawaz, Meinrad; Langer, Harald F

2017-06-01

Successful percutaneous mitral valve repair (PMVR) in patients with severe mitral regurgitation (MR) causes changes in hemodynamics. Echocardiographic calculation of cardiac output (CO) has not been evaluated in the setting of PMVR, so far. Here we evaluated hemodynamics before and after PMVR with the MitraClip system using pulmonary artery catheterization, transthoracic (TTE) and transesophageal (TEE) echocardiography. 101 patients with severe MR not eligible for conventional surgery underwent PMVR. Hemodynamic parameters were determined during and after the intervention. We evaluated changes in CO and pulmonary artery systolic pressure before and after PMVR. CO was determined with invasive parameters using the Fick method (COi) and by a combination of TTE and TEE (COe). All patients had successful clip implantation, which was associated with increased COi (from 4.6±1.4l/min to 5.4±1.6l/min, p<0.001). Furthermore, pulmonary artery systolic pressure (PASP) showed a significant decrease after PMVR (47.6±16.1 before, 44.7±15.5mmHg after, p=0.01). In accordance with invasive measurements, COe increased significantly (COe from 4.3±1.7l/min to 4.8±1.7l/min, p=0.003). Comparing both methods to calculate CO, we observed good agreement between COi and COe using Bland Altman plots. CO increased significantly after PMVR as determined by echocardiography based and invasive calculation of hemodynamics during PMVR. COe shows good agreement with COi before and after the intervention and, thus, represents a potential non-invasive method to determine CO in patients with MR not accessible by conventional surgery. Copyright © 2017 Elsevier B.V. All rights reserved.

[Measurement of cardiac output by thermodilution with a diode as a temperature sensor].

PubMed

Díaz Fernández, A; Benítez, D; Sánchez Tello, G; Márquez, L A

1979-01-01

An area integrator for the thermodilution curve in cardiac output measurement is described. A new temperature sensor is used, a diode with some advantages over the thermistor normally used. The main advantages are: easy calibration and replacement, and broad range of linearity. The cardiac output values obtained in dog with the integrator follow a linear relationship with those of the flowmeter. In simultaneous measurements the correlation is R = 0.96. Using a diode as temperature sensor a modification of the Steward Hamilton equation (used for thermistor) is necessary. With this new equation a monogram is performed to calculate the cardiac output from the area given by the numerical integrator.

Use of the single-breath method of estimating cardiac output during exercise-stress testing.

NASA Technical Reports Server (NTRS)

Buderer, M. C.; Rummel, J. A.; Sawin, C. F.; Mauldin, D. G.

1973-01-01

The single-breath cardiac output measurement technique of Kim et al. (1966) has been modified for use in obtaining cardiac output measurements during exercise-stress tests on Apollo astronauts. The modifications involve the use of a respiratory mass spectrometer for data acquisition and a digital computer program for data analysis. The variation of the modified method for triplicate steady-state cardiac output measurements was plus or minus 1 liter/min. The combined physiological and methodological variation seen during a set of three exercise tests on a series of subjects was 1 to 2.5 liter/min. Comparison of the modified method with the direct Fick technique showed that although the single-breath values were consistently low, the scatter of data was small and the correlation between the two methods was high. Possible reasons for the low single-breath cardiac output values are discussed.

Cardiac output monitoring using indicator-dilution techniques: basics, limits, and perspectives.

PubMed

Reuter, Daniel A; Huang, Cecil; Edrich, Thomas; Shernan, Stanton K; Eltzschig, Holger K

2010-03-01

The ability to monitor cardiac output is one of the important cornerstones of hemodynamic assessment for managing critically ill patients at increased risk for developing cardiac complications, and in particular in patients with preexisting cardiovascular comorbidities. For >30 years, single-bolus thermodilution measurement through a pulmonary artery catheter for assessment of cardiac output has been widely accepted as the "clinical standard" for advanced hemodynamic monitoring. In this article, we review this clinical standard, along with current alternatives also based on the indicator-dilution technique, such as the transcardiopulmonary thermodilution and lithium dilution techniques. In this review, not only the underlying technical principles and the unique features but also the limitations of each application of indicator dilution are outlined.

Decreased 2,3-diphosphoglycerate concentration in low cardiac output patients and its influence on the determination of in vivo p50.

PubMed

Piccioni, Marilde A; Cestari, Idágene A; Strunz, Célia M C; Auler, José O

2003-08-01

We investigated whether 2,3-diphosphoglycerate (2,3-DPG) is altered in patients with low cardiac output and the influence of its concentration on the calculation of in vivo P(50). Biochemical and blood gas analysis were performed along with the measurement of cardiac output and body temperature in 13 patients submitted to cardiopulmonary bypass surgeries without the use of donor blood. In vivo P(50) was calculated using the measured (P(50m)) and the estimated 2,3-DPG (P(50e)). 2,3-DPG concentration was lower in these patients when compared to the values obtained in normal volunteers (6.9 +/- 2.2 vs. 11.9 +/- 2.4 microm/gHb). P(50m) was lower than P(50e) (21.6 +/- 1.1 vs. 30.1 +/- 1.2 mm Hg) at all time points. Our data show that in patients with low cardiac output, 2,3-DPG concentration is reduced. Therefore, in these patients, the use of standard values for this variable may introduce an error in the calculation of in vivo P(50).

Chronic resuscitation after trauma-hemorrhage and acute fluid replacement improves hepatocellular function and cardiac output.

PubMed

Remmers, D E; Wang, P; Cioffi, W G; Bland, K I; Chaudry, I H

1998-01-01

To determine whether prolonged (chronic) resuscitation has any beneficial effects on cardiac output and hepatocellular function after trauma-hemorrhage and acute fluid replacement. Acute fluid resuscitation after trauma-hemorrhage restores but does not maintain the depressed hepatocellular function and cardiac output. Male Sprague-Dawley rats underwent a 5-cm laparotomy (i.e., trauma was induced) and were bled to and maintained at a mean arterial pressure of 40 mmHg until 40% of maximal bleed-out volume was returned in the form of Ringer's lactate (RL). The animals were acutely resuscitated with RL using 4 times the volume of maximum bleed-out over 60 minutes, followed by chronic resuscitation of 0, 5, or 10 mL/kg/hr RL for 20 hours. Hepatocellular function was determined by an in vivo indocyanine green clearance technique. Hepatic microvascular blood flow was assessed by laser Doppler flowmetry. Plasma levels of interleukin-6 (IL-6) were determined by bioassay. Chronic resuscitation with 5 mL/kg/hr RL, but not with 0 or 10 mL/kg/hr RL, restored cardiac output, hepatocellular function, and hepatic microvascular blood flow at 20 hours after hemorrhage. The regimen above also reduced plasma IL-6 levels. Because chronic resuscitation with 5 mL/kg/hr RL after trauma-hemorrhage and acute fluid replacement restored hepatocellular function and hepatic microvascular blood flow and decreased plasma levels of IL-6, we propose that chronic fluid resuscitation in addition to acute fluid replacement should be routinely used in experimental studies of trauma-hemorrhage.

Exercise cardiac output following Skylab missions - The second manned Skylab mission

NASA Technical Reports Server (NTRS)

Buderer, M. C.; Mauldin, D. G.; Rummel, J. A.; Michel, E. L.; Sawin, C. F.

1976-01-01

Cardiac output was measured during preflight and postflight exercise-stress tests on the Skylab astronauts. In the postflight tests immediately following the 28-, 59-, and 84-d earth orbital missions, the astronauts exhibited an approximate 30% decrease in cardiac output coupled with an approximate 50% decrease in cardiac stroke volume during exercise. These changes were accompanied by elevated heart rates and significant increases in total systemic peripheral vascular resistance. Mean arterial pressure was unchanged. All parameters returned to normal preflight values within 30 d of the end of the orbital period. Duration of the zero-G exposure did not appear to influence either the magnitude of the hemodynamic changes or the time-course of their return to normal. These results are discussed in relation to other cardiovascular findings and possible mechanisms responsible for the observations are outlined.

Correlation of carotid blood flow and corrected carotid flow time with invasive cardiac output measurements.

PubMed

Ma, Irene W Y; Caplin, Joshua D; Azad, Aftab; Wilson, Christina; Fifer, Michael A; Bagchi, Aranya; Liteplo, Andrew S; Noble, Vicki E

2017-12-01

Non-invasive measures that can accurately estimate cardiac output may help identify volume-responsive patients. This study seeks to compare two non-invasive measures (corrected carotid flow time and carotid blood flow) and their correlations with invasive reference measurements of cardiac output. Consenting adult patients (n = 51) at Massachusetts General Hospital cardiac catheterization laboratory undergoing right heart catheterization between February and April 2016 were included. Carotid ultrasound images were obtained concurrently with cardiac output measurements, obtained by the thermodilution method in the absence of severe tricuspid regurgitation and by the Fick oxygen method otherwise. Corrected carotid flow time was calculated as systole time/√cycle time. Carotid blood flow was calculated as π × (carotid diameter) 2 /4 × velocity time integral × heart rate. Measurements were obtained using a single carotid waveform and an average of three carotid waveforms for both measures. Single waveform measurements of corrected flow time did not correlate with cardiac output (ρ = 0.25, 95% CI -0.03 to 0.49, p = 0.08), but an average of three waveforms correlated significantly, although weakly (ρ = 0.29, 95% CI 0.02-0.53, p = 0.046). Carotid blood flow measurements correlated moderately with cardiac output regardless of if single waveform or an average of three waveforms were used: ρ = 0.44, 95% CI 0.18-0.63, p = 0.004, and ρ = 0.41, 95% CI 0.16-0.62, p = 0.004, respectively. Carotid blood flow may be a better marker of cardiac output and less subject to measurements issues than corrected carotid flow time.

Serum cortisol concentration with exploratory cut-off values do not predict the effects of hydrocortisone administration in children with low cardiac output after cardiac surgery.

PubMed

Verweij, E J; Hogenbirk, Karin; Roest, Arno A W; van Brempt, Ronald; Hazekamp, Mark G; de Jonge, Evert

2012-10-01

Low cardiac output syndrome is common after paediatric cardiac surgery. Previous studies suggested that hydrocortisone administration may improve haemodynamic stability in case of resistant low cardiac output syndrome in critically ill children. This study was set up to test the hypothesis that the effects of hydrocortisone on haemodynamics in children with low cardiac output syndrome depend on the presence of (relative) adrenal insufficiency. A retrospective study was done on paediatric patients who received hydrocortisone when diagnosed with resistant low cardiac output syndrome after paediatric cardiac surgery in the period from 1 November 2005 to 31 December 2008. We studied the difference in effects of treatment with hydrocortisone administration between patients with adrenal insufficiency defined as an exploratory cut-off value of total cortisol of <100 nmol/l and patients with a serum total cortisol of ≥ 100 nmol/l. A total of 62 of patients were enrolled, meeting the inclusion criteria for low cardiac output syndrome. Thirty-two patients were assigned to Group 1 (<100 nmol/l) and 30 were assigned to Group 2 (≥ 100 nmol/l). Haemodynamics improved after hydrocortisone administration, with an increase in blood pressure, a decrease in administered vasopressors and inotropic drugs, an increase in urine production and a decrease in plasma lactate concentrations. The effects of treatment with hydrocortisone in children with low cardiac output after cardiac surgery was similar in patients with a low baseline serum cortisol concentration and those with normal baseline cortisol levels. A cortisol value using an exploratory cut-off value of 100 nmol/l for adrenal insufficiency should not be used as a criterion to treat these patients with hydrocortisone.

Evaluation of noninvasive cardiac output methods during exercise

NASA Technical Reports Server (NTRS)

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

1992-01-01

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.

Non-invasive cardiac output trending during exercise recovery on a bathroom-scale-based ballistocardiograph.

PubMed

Inan, O T; Etemadi, M; Paloma, A; Giovangrandi, L; Kovacs, G T A

2009-03-01

Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R(2) = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland-Altman methods for assessing agreement, the mean bias was found to be -0.5% (+/-24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional.

Measurement of cardiac output using improved chromatographic analysis of sulfur hexafluoride (SF6).

PubMed

Klocke, F J; Roberts, D L; Farhi, E R; Naughton, B J; Sekovski, B; Klocke, R A

1977-06-01

A constant current variable frequency pulsed electron capture detector has been incorporated into the gas chromatographic analysis of trace amounts of sulfur hexafluoride (SF6) in water and blood. The resulting system offers a broader effective operating range than more conventional electron capture units and has been utilized for measurements of cardiac output employing constant-rate infusion of dissolved SF6. The SF6 technique has been validated against direct volumetric measurements of cardiac output in a canine right-heart bypass preparation and used subsequently for rapidly repeated measurements in conscious animals and man.

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

NASA Technical Reports Server (NTRS)

1980-01-01

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.

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-03-01

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

Impedance cardiography: a comparison of cardiac output vs waveform analysis for assessing left ventricular systolic dysfunction.

PubMed

DeMarzo, Arthur P; Kelly, Russell F; Calvin, James E

2007-01-01

Early detection of asymptomatic left ventricular systolic dysfunction (LVSD) is beneficial in managing heart failure. Recent studies have cast doubt on the usefulness of cardiac output as an indicator of LVSD. In impedance cardiography (ICG), the dZ/dt waveform has a systolic wave called the E wave. This study looked at measurements of the amplitude and area of the E wave compared with ICG-derived cardiac output, stroke volume, cardiac index, and stroke index as methods of assessing LVSD. ICG data were obtained from patients (n=26) admitted to a coronary care unit. Clinical LVSD severity was stratified into 4 groups (none, mild, moderate, and severe) based on echocardiography data and standard clinical assessment by a cardiologist blinded to ICG data. Statistical analysis showed that the E wave amplitude and area were better indicators of the level of LVSD than cardiac output, stroke volume, cardiac index, or stroke index. ICG waveform analysis has potential as a simple point-of-care test for detecting LVSD in asymptomatic patients at high risk for developing heart failure and for monitoring LVSD in patients being treated for heart failure.

Comparison of pulsed Doppler and thermodilution methods for measuring cardiac output in critically ill patients.

PubMed

Donovan, K D; Dobb, G J; Newman, M A; Hockings, B E; Ireland, M

1987-09-01

We obtained 145 consecutive cardiac output measurements in 38 critically ill patients, using the invasive thermodilution and the noninvasive pulsed Doppler methods. The mean thermodilution cardiac output (TDCO) was 5.7 +/- 1.87 L/min and the mean pulsed Doppler cardiac output (PDCO) was 5.16 +/- 1.66 L/min. The mean difference between the two measurements was 0.51 L/min with an SD greater than 1.6 L/min, reflecting the scattering of results. The overall correlation coefficient was .58. The intercepts were large and the regression equation some way from the line of equal values (TDCO = 2.28 + 0.66 PDCO). When the results were analyzed according to diagnosis or by group experience, there were some differences in the bias of the estimate; however, the SD of the difference between methods was greater than one liter/min in all groups. Thus, the pulsed Doppler method failed to estimate accurately TDCO in critically ill patients.

Evaluation of concordance among three cardiac output measurement techniques in adult patients during cardiovascular surgery postoperative care.

PubMed

Muñoz, L; Velandia, A; Reyes, L E; Arevalo-Rodríguez, I; Mejía, C; Asprilla, D; Uribe, D V; Arevalo, J J

2017-12-01

The standard method for cardiac output measuring is thermodilution although it is an invasive technique. Transesophageal Echocardiography (TEE) offers a dynamic and functional alternative to thermodilution. Analyze concordance between two TEE methods and thermodilution for cardiac output assessment. Observational concordance study in cardiovascular surgery patients that required pulmonary artery catheter. TEE cardiac output measurement at both mitral annulus (MA) and left ventricle outflow tract (LVOT) were performed. Results were compared with thermodilution. Correlation was evaluated by Lin's concordance correlation coefficient and Bland-Altman analysis. Statistical analysis was undertaken in STATA 13.0. Twenty-five patients were enrolled. Fifty two percent of patients were male, median age and ejection fraction was 63 years and 35% respectively. Median thermodilution, LVOT and MA -measured cardiac output was 3.25 L/min, 3.46 L/min and 8.4 L/min respectively. Different values between thermodilution and MA measurements were found (Lin concordance=0.071; Confidence Interval 95%=-0.009 to 0.151; Spearman's correlation=0.22) as values between thermodilution and LVOT (Lin concordance=0.232; Confidence Interval 95%=-0.12 a 0.537; Spearman's correlation 0.28). Bland-Altman analysis showed greater difference between MA measurements and thermodilution (DM=-0.408; Bland-Altman Limits=-0.809 to -0.007), than the other echocardiographic findings (DM=0.007; Bland-Altman Limits=-0.441 to 0.428). Results from cardiac output measurement by doppler and 2D-TEE on both MA and LVOT do not correlate with those obtained by thermodilution. Copyright © 2017 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration

PubMed Central

Prasser, Christopher; Bele, Sylvia; Keyl, Cornelius; Schweiger, Stefan; Trabold, Benedikt; Amann, Matthias; Welnhofer, Julia; Wiesenack, Christoph

2007-01-01

Background Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (COPAC) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (COAP) device (FloTrac™, Vigileo™; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU) using COPAC as the method of reference. Methods We studied 20 critically ill patients, aged 16 to 74 years (mean, 55.5 ± 18.8 years), who required both arterial and pulmonary artery pressure monitoring. COPAC measurements were performed at least every 4 hours and calculated as the average of 3 measurements, while COAP values were taken immediately at the end of bolus determinations. Accuracy of measurements was assessed by calculating the bias and limits of agreement using the method described by Bland and Altman. Results A total of 164 coupled measurements were obtained. Absolute values of COPAC ranged from 2.80 to 10.80 l/min (mean 5.93 ± 1.55 l/min). The bias and limits of agreement between COPAC and COAP for unequal numbers of replicates was 0.02 ± 2.92 l/min. The percentage error between COPAC and COAP was 49.3%. The bias between percentage changes in COPAC (ΔCOPAC) and percentage changes in COAP (ΔCOAP) for consecutive measurements was -0.70% ± 32.28%. COPAC and COAP showed a Pearson correlation coefficient of 0.58 (p < 0.01), while the correlation coefficient between ΔCOPAC and ΔCOAP was 0.46 (p < 0.01). Conclusion Although the COAP algorithm shows a minimal bias with COPAC over a wide range of values in an inhomogeneous group of critically ill patients, the scattering of the data remains relative wide. Therefore

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

PubMed

Vogelaere, P; Deklunder, G; Lecroart, J

1995-08-01

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 degrees C) immersion for 60 min. Cardiac output was measured using a dual-beam Doppler flow meter. During immersion in cold water, cardiac frequency (fc) 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, fc 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 (Vs) 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) l min-1 (P < 0.05) and its change with time was a function of both Vs and fc. 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.

The use of cardiac output monitoring to guide the administration of intravenous fluid during hyperthermic intraperitoneal chemotherapy.

PubMed

Thanigaimani, K; Mohamed, F; Cecil, T; Moran, B J; Bell, J

2013-12-01

The optimal strategy for intravenous (IV) fluid management during administration of hyperthermic intraperitoneal chemotherapy (HIPEC) is unclear. In this prospective study we describe the use of a LiDCOrapid™ (LiDCO, Cambridge, UK) cardiac output monitor to guide IV fluid management during cytoreductive surgery (CRS) with HIPEC. The aim of this study was to determine whether cardiac output monitoring will allow close maintenance of physiological parameters during the HIPEC phase. Twenty-five patients who underwent CRS combined with HIPEC were included in the study. Intra-operative IV fluid boluses were titrated using parameters measured by the LiDCOrapid™ monitor. Stroke volume variation was maintained below 10% with fluid boluses and mean arterial pressure was maintained within 20% of the baseline figure with vasopressors. There was no significant change in heart rate and cardiac output. The systemic vascular resistance dropped from an average of 966 dyn.s/cm-5 to 797 dyn s/cm(5) at 60 min during the HIPEC phase (P = 0.62) despite an increase in the dose of phenylepherine. The average total volume of fluid given was 748 ml in the first 30 min and 630 ml in the second 30 min with an average urine output of 307 and 445 ml, respectively. The change in lactate levels was not statistically or clinically significant. LiDCOrapid™ is an effective noninvasive tool for guiding fluid management in this population. It allows the anaesthesiologist to maintain tight control of essential physiological parameters during a phase of the procedure in which there is a risk of renal injury. Colorectal Disease © 2013 The Association of Coloproctology of Great Britain and Ireland.

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

NASA Astrophysics Data System (ADS)

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

1995-03-01

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.

Comparison of an Endotracheal Cardiac Output Monitor to a Pulmonary Artery Catheter

DTIC Science & Technology

2017-12-04

of a FDA approved device, the CONMED endotracheal cardiac output monitor (ECOM) ™ apparatus, by comparing it to the Edwards Vig ilance II monitor...and Use Committee (FWH 20140100A). Results Using GraphPad Prism® to conduct non-linear fit analyses comparing the slopes of the curves for ECOM

Cardiac output increases prior to development of pulmonary edema after re-expansion of spontaneous pneumothorax.

PubMed

Tan, H C; Mak, K H; Johan, A; Wang, Y T; Poh, S C

2002-06-01

Pulmonary edema following reexpansion of spontaneous pneumothorax is an uncommon complication. The underlying mechanism of this condition is unclear. We report the hemodynamic characteristics in a series of 7 male patients with spontaneous large (>50%) pneumothoraces of > or = 24 h and correlate the changes with reexpansion pulmonary edema (REPE). A pulmonary artery floatation catheter was inserted and hemodynamic data were obtained before therapeutic chest tube insertion, 1 h after chest tube insertion and the following day. Four (57%) patients developed REPE. There was a tendency for larger pneumothorax to develop REPE. Capillary wedge pressure did not change significantly 1 h after the insertion of chest tube in all our patients. Cardiac output increased significantly in patients who developed REPE compared to those who did not (+ 1.06 l/min vs -0.27 l/min; P = 0.03) 1 h after insertion of chest tube. One patient did not develop pulmonary edema despite having a large (> 80%) pneumothorax. His cardiac output did not rise 1 h after chest tube insertion. REPE is not an uncommon complication following chest tube drainage in patients with large and long-standing pneumothorax. The increase in cardiac output after chest tube insertion may be associated with subsequent development of REPE.

Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.

PubMed

Schramm, P; Tzanova, I; Hagen, F; Berres, M; Closhen, D; Pestel, G; Engelhard, K

2016-10-01

Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS ® and FORE-SIGHT ® . Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS ® was 70 (sd 9)%; thereafter, it increased by 0.0187% min -1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT ® started at 68 (sd 13)% and increased by 0.0142% min -1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min -1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. NCT01275898. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output.

PubMed

Smerup, Morten; Damkjær, Mads; Brøndum, Emil; Baandrup, Ulrik T; Kristiansen, Steen Buus; Nygaard, Hans; Funder, Jonas; Aalkjær, Christian; Sauer, Cathrine; Buchanan, Rasmus; Bertelsen, Mads Frost; Østergaard, Kristine; Grøndahl, Carsten; Candy, Geoffrey; Hasenkam, J Michael; Secher, Niels H; Bie, Peter; Wang, Tobias

2016-02-01

Giraffes--the tallest extant animals on Earth--are renowned for their high central arterial blood pressure, which is necessary to secure brain perfusion. Arterial pressure may exceed 300 mmHg and has historically been attributed to an exceptionally large heart. Recently, this has been refuted by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It thus remains unexplained how the normal-sized giraffe heart generates such massive arterial pressures. We hypothesized that giraffe hearts have a small intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min(-1), respectively. End-diastolic and end-systolic volumes were 521±61 ml and 228±42 ml, respectively, yielding an ejection fraction of 56±4% and a stroke volume of 0.59 ml kg(-1). Left ventricular circumferential wall stress was 7.83±1.76 kPa. We conclude that, relative to body mass, a small left ventricular cavity and a low stroke volume characterizes the giraffe heart. The adaptations result in typical mammalian left ventricular wall tensions, but produce a lowered cardiac output. © 2016. Published by The Company of Biologists Ltd.

Role of the Frank-Starling mechanism in maintaining cardiac output during increasing levels of treadmill exercise in beta-blocked normal men.

PubMed

Bevilacqua, M; Savonitto, S; Bosisio, E; Chebat, E; Bertora, P L; Sardina, M; Norbiato, G

1989-04-01

To determine the effects of beta blockade on hemodynamics during increasing levels of treadmill exercise, 10 healthy volunteers were studied after 1 week of placebo, and then after 1 week of treatment with oral propranolol, 80 mg twice daily, or dilevalol, 400 mg once daily. The study was randomized and double-blind, with a crossover sequence. Hemodynamics were measured by CO2 rebreathing at rest and at 25, 50, 75 and 100% of VO2 max. After placebo, cardiac output increased from 5.8 +/- 2.1 (rest), to 19.4 +/- 6.4 liters/min (100% VO2 max), mainly due to an increase in heart rate from 84 +/- 6 to 169 +/- 15 beats/min. Stroke volume increased from 70 +/- 27 (rest), to 137 +/- 65 ml (25% VO2 max), and then leveled off to 116 +/- 41 at 100% VO2 max. After both beta blockers, exercise cardiac output was maintained at 100% VO2 max: 20.1 +/- 9.3 liters/min with propranolol and 19.1 +/- 8.6 with dilevalol. However, a significant reduction versus placebo values was observed for cardiac output at 25% VO2 max, from 13.7 +/- 5.9 during placebo, to 9.4 +/- 2.5 during propranolol, and to 9.6 +/- 2.3 during dilevalol (both p less than 0.01 vs placebo). Maintenance of cardiac output with both beta blockers at higher levels of exercise came from an increased stroke volume (p less than 0.05 vs placebo), while heart rate (in beats/min) was greatly reduced (propranolol 61.6 +/- 9.4 rest, 90.1 +/- 10.7 at 100% VO2 max; dilevalol 70.8 +/- 6.4 rest, 99.2 +/- 11.8 at 100% VO2 max, p less than 0.01 vs placebo for each).(ABSTRACT TRUNCATED AT 250 WORDS)

Correlations between near-infrared spectroscopy, perfusion index, and cardiac outputs in extremely preterm infants in the first 72 h of life.

PubMed

Janaillac, Marie; Beausoleil, Thierry P; Barrington, Keith J; Raboisson, Marie-Josée; Karam, Oliver; Dehaes, Mathieu; Lapointe, Anie

2018-04-01

Haemodynamic assessment during the transitional period in preterm infants is challenging. We aimed to describe the relationships between cerebral regional tissue oxygen saturation (CrSO 2 ), perfusion index (PI), echocardiographic, and clinical parameters in extremely preterm infants in their first 72 h of life. Twenty newborns born at < 28 weeks of gestation were continuously monitored with CrSO 2 and preductal PI. Cardiac output was measured at H6, H24, H48, and H72. The median gestational age and birth weight were 25.0 weeks (24-26) and 750 g (655-920), respectively. CrSO 2 and preductal PI had r values < 0.35 with blood gases, lactates, haemoglobin, and mean blood pressure. Cardiac output significantly increased over the 72 h of the study period. Fifteen patients had at least one episode of low left and/or right ventricular output (RVO), during which there was a strong correlation between CrSO 2 and superior vena cava (SVC) flow (at H6 (r = 0.74) and H24 (r = 0.86)) and between PI and RVO (at H6 (r = 0.68) and H24 (r = 0.92)). Five patients had low SVC flow (≤ 40 mL/kg/min) at H6, during which PI was strongly correlated with RVO (r = 0.98). CrSO 2 and preductal PI are strongly correlated with cardiac output during low cardiac output states. What is Known: • Perfusion index and near-infrared spectroscopy are non-invasive tools to evaluate haemodynamics in preterm infants. • Pre- and postductal perfusion indexes strongly correlate with left ventricular output in term infants, and near-infrared spectroscopy has been validated to assess cerebral oxygenation in term and preterm infants. What is New: • Cerebral regional tissue oxygen saturation and preductal perfusion index were strongly correlated with cardiac output during low cardiac output states. • The strength of the correlation between cerebral regional tissue oxygen saturation, preductal perfusion index, and cardiac output varied in the first 72 h of life, reflecting

Comparison of multiple non-invasive methods of measuring cardiac output during pregnancy reveals marked heterogeneity in the magnitude of cardiac output change between women.

PubMed

Petersen, John W; Liu, Jing; Chi, Yueh-Yun; Lingis, Melissa; Williams, R Stan; Rhoton-Vlasak, Alice; Segal, Mark S; Conrad, Kirk P

2017-04-01

Various non-invasive methods are available to measure cardiac output (CO) during pregnancy. We compared serial measures of CO using various methods to determine which provided the least variability. Ten patients with spontaneous pregnancy had estimation of CO at baseline prior to becoming pregnant and at the end of the first and third trimesters. Echocardiographic data were used to estimate CO using the Teichholz method, Simpson's biplane method, and the Doppler determined velocity time integral (VTI) method. In addition, a Bioz Dx device was used to estimate CO by impedance cardiography. CO estimated with the VTI method had the lowest beat-to-beat variability. CO estimated with the VTI method was higher than CO estimated with the 2D-Teichholz method and Simpson's method. The percent change in CO during pregnancy was similar for all echo methods (VTI, Teichholz, and Simpson's biplane). Baseline CO determined with impedance cardiography was higher than CO determined with the VTI method. However, change in CO during pregnancy was significantly lower when measured with impedance cardiography. There was marked heterogeneity in the degree of rise in CO during the first trimester (-3 to 55%). The wide variation in the gestational rise in CO was unexpected, and at least in part secondary to variable increase in heart rate. We recommend the use of the Doppler determined VTI method for the estimation of CO in pregnancy. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Cardiac output and systemic vascular resistance: Clinical assessment compared with a noninvasive objective measurement in children with shock.

PubMed

Razavi, Asma; Newth, Christopher J L; Khemani, Robinder G; Beltramo, Fernando; Ross, Patrick A

2017-06-01

To evaluate physician assessment of cardiac output and systemic vascular resistance in patients with shock compared with an ultrasonic cardiac output monitor (USCOM). To explore potential changes in therapy decisions if USCOM data were available using physician intervention answers. Double-blinded, prospective, observational study in a tertiary hospital pediatric intensive care unit. Forty children (<18years) admitted with shock, requiring ongoing volume resuscitation or inotropic support. Two to 3 physicians clinically assessed cardiac output and systemic vascular resistance, categorizing them as high, normal, or low. An investigator simultaneously measured cardiac index (CI) and systemic vascular resistance index (SVRI) with USCOM categorized as high, normal, or low. Overall agreement between physician and USCOM for CI (48.5% [κ = 0.18]) and SVRI (45.9% [κ = 0.16]) was poor. Interobserver agreement was also poor for CI (58.7% [κ = 0.33]) and SVRI (52.3% [κ = 0.28]). Comparing theoretical physician interventions to "acceptable" or "unacceptable" clinical interventions, based on USCOM measurement, 56 (21%) physician interventions were found to be "unacceptable." There is poor agreement between physician-assessed CI and SVRI and USCOM, with significant interobserver variability among physicians. Objective measurement of CI and SVRI may reduce variability and improve diagnostic accuracy. Copyright © 2016 Elsevier Inc. All rights reserved.

Beat-by-beat analysis of cardiac output and blood pressure responses to short-term barostimulation in different body positions

NASA Astrophysics Data System (ADS)

Hildebrandt, Wulf; Schütze, Harald; Stegemann, J.

Rapid quantification of the human baro-reflex control of heart rate has been achieved on a beat-by-beat basis using a neck-chamber with quick ECG-triggered pressure changes. Referring to recent findings on heart rate and stroke volume, the present study uses this technique to compare cardiac output as well as blood pressure changes in supine and upright position to investigate feedback effects and to confirm postural reflex modifications not revealed by RR-interval changes. A suction profile starting at +40 mmHg and running 7 steps of pressure decrease down to -65 mmHg was examined in 0° and 90° tilting position while beat-by-beat recordings were done of heart rate, stroke volume (impedance-cardiography) and blood pressure (Finapres tm) (n=16). The percentual heart rate decrease failed to be significantly different between positions. A suction-induced stroke volume increase led to a cardiac output almost maintained when supine and significantly increased when upright. A decrease in all blood pressure values was found during suction, except for systolic values in upright position which increased. Conclusively, (a) it is confirmed that different inotropy accounts for the seen gravitational effect on the cardiac output not represented by heart rate; (b) identical suction levels in different positions lead to different stimuli at the carotid receptor. This interference has to be considered in microgravity studies by beat-by-beat measurement of cardiac output and blood pressure.

Improved hepatic arterial fraction estimation using cardiac output correction of arterial input functions for liver DCE MRI

NASA Astrophysics Data System (ADS)

Chouhan, Manil D.; Bainbridge, Alan; Atkinson, David; Punwani, Shonit; Mookerjee, Rajeshwar P.; Lythgoe, Mark F.; Taylor, Stuart A.

2017-02-01

Liver dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling could be useful in the assessment of diffuse liver disease and focal liver lesions, but is compromised by errors in arterial input function (AIF) sampling. In this study, we apply cardiac output correction to arterial input functions (AIFs) for liver DCE MRI and investigate the effect on dual-input single compartment hepatic perfusion parameter estimation and reproducibility. Thirteen healthy volunteers (28.7  ±  1.94 years, seven males) underwent liver DCE MRI and cardiac output measurement using aortic root phase contrast MRI (PCMRI), with reproducibility (n  =  9) measured at 7 d. Cardiac output AIF correction was undertaken by constraining the first pass AIF enhancement curve using the indicator-dilution principle. Hepatic perfusion parameters with and without cardiac output AIF correction were compared and 7 d reproducibility assessed. Differences between cardiac output corrected and uncorrected liver DCE MRI portal venous (PV) perfusion (p  =  0.066), total liver blood flow (TLBF) (p  =  0.101), hepatic arterial (HA) fraction (p  =  0.895), mean transit time (MTT) (p  =  0.646), distribution volume (DV) (p  =  0.890) were not significantly different. Seven day corrected HA fraction reproducibility was improved (mean difference 0.3%, Bland-Altman 95% limits-of-agreement (BA95%LoA)  ±27.9%, coefficient of variation (CoV) 61.4% versus 9.3%, ±35.5%, 81.7% respectively without correction). Seven day uncorrected PV perfusion was also improved (mean difference 9.3 ml min-1/100 g, BA95%LoA  ±506.1 ml min-1/100 g, CoV 64.1% versus 0.9 ml min-1/100 g, ±562.8 ml min-1/100 g, 65.1% respectively with correction) as was uncorrected TLBF (mean difference 43.8 ml min-1/100 g, BA95%LoA  ±586.7 ml min-1/ 100 g, CoV 58.3% versus 13.3 ml min-1/100 g, ±661.5 ml min-1/100 g, 60.9% respectively with correction

Clinical usefulness of the definitions for defining characteristics of activity intolerance, excess fluid volume and decreased cardiac output in decompensated heart failure: a descriptive exploratory study.

PubMed

de Souza, Vanessa; Zeitoun, Sandra Salloum; Lopes, Camila Takao; de Oliveira, Ana Paula Dias; Lopes, Juliana de Lima; de Barros, Alba Lucia Bottura Leite

2015-09-01

To assess the clinical usefulness of the operational definitions for the defining characteristics of the NANDA International nursing diagnoses, activity intolerance, decreased cardiac output and excess fluid volume, and the concomitant presence of those diagnoses in patients with decompensated heart failure. Content validity of the operational definitions for the defining characteristics of activity intolerance, excess fluid volume and decreased cardiac output have been previously validated by experts. Their clinical usefulness requires clinical validation. This was a descriptive exploratory study. Two expert nurses independently assessed 25 patients with decompensated heart failure for the presence or absence of 29 defining characteristics. Interrater reliability was analysed using the Kappa coefficient as a measure of clinical usefulness. The Fisher's exact test was used to test the association of the defining characteristics of activity intolerance and excess fluid volume in the presence of decreased cardiac output, and the correlation between the three diagnoses. Assessments regarding the presence of all defining characteristics reached 100% agreement, except with anxiety. Five defining characteristics of excess fluid volume were significantly associated with the presence of decreased cardiac output. Concomitant presence of the three diagnoses occurred in 80% of the patients. However, there was no significant correlation between the three diagnoses. The operational definitions for the diagnoses had strong interrater reliability, therefore they were considered clinically useful. Only five defining characteristics were representative of the association between excess fluid volume and decreased cardiac output. Therefore, excess fluid volume is related to decreased cardiac output, although these diagnoses are not necessarily associated with activity intolerance. The operational definitions may favour early recognition of the sequence of responses to decompensation

The Higher the Insulin Resistance the Lower the Cardiac Output in Men with Type 1 Diabetes During the Maximal Exercise Test.

PubMed

Niedzwiecki, Pawel; Naskret, Dariusz; Pilacinski, Stanislaw; Pempera, Maciej; Uruska, Aleksandra; Adamska, Anna; Zozulinska-Ziolkiewicz, Dorota

2017-06-01

The aim of this study was to assess the hemodynamic parameters analyzed in bioimpedance cardiography during maximal exercise in patients with type 1 diabetes differing in insulin resistance. The study group consisted of 40 men with type 1 diabetes. Tissue sensitivity to insulin was assessed on the basis of the glucose disposal rate (GDR) analyzed during hyperinsulinemic-euglycemic clamp. Patients were divided into groups with GDR <4.5 mg/kg/min (G1 group-lower insulin sensitivity) and GDR ≥4.5 mg/kg/min (G2 group-higher insulin sensitivity). During the exercise test, the heart rate, systolic volume, cardiac output, cardiac index were measured by the impedance meter (PhysioFlow). Compared with the G2 group, the G1 group had a lower cardiac output (CO): during exercise 8.6 (IQR 7.7-10.0) versus 12.8 (IQR 10.8-13.7) L/min; P < 0.0001, at the maximal effort 13.1 (IQR 12.2-16.7) versus 18.6 (IQR 16.9-20.2) L/min; P = 0.001, and during observation after exercise 8.4 (IQR 6.3-9.6) versus 11.9 (IQR 10.1-13.1) L/min; P < 0.0001. We noticed a positive correlation of GDR and cardiac output: during the exercise test (r = 0.63, P = 0.0002), at the maximal effort (Rs 0.56, P = 0.001), and during observation after the exercise test (r = 0.72, P < 0.0001). In multivariate logistic regression, cardiac output during exercise and during observation was associated with high GDR, regardless of the age and duration of diabetes [OR: 1.98 (95% CI 1.10-3.56), P = 0.02 and OR: 1.91 (95% CI 1.05-3.48), P = 0.03; respectively]. In nonobese subjects with type 1 diabetes, with good metabolic control, insulin resistance is associated with cardiac hemodynamic parameters assessed during and after exercise. The higher the insulin resistance the lower the cardiac output during maximal exercise in men with type 1 diabetes.

Cardiac output and performance during a marathon race in middle-aged recreational runners.

PubMed

Billat, Véronique L; Petot, Hélène; Landrain, Morgan; Meilland, Renaud; Koralsztein, Jean Pierre; Mille-Hamard, Laurence

2012-01-01

Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3 hr 30 min ± 45 min). Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively). Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO × m(-1)) (r = -0.65, P < 0.01) and positively correlated with the runner's ability to complete the race at a high percentage of the speed at maximal SV (r = 0.83, P < 0.0002). Our results showed that marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners.

Increases in Cardiac Output and Oxygen Consumption During Enhanced External Counterpulsation.

PubMed

Ahlbom, Magnus; Hagerman, Inger; Ståhlberg, Marcus; Manouras, Aristomenis; Förstedt, Gunilla; Wu, Eline; Lund, Lars H

2016-11-01

Regular enhanced external counterpulsation (EECP) improves exercise capacity possibly through a training effect, but the roles of oxygen consumption (VO 2 ) vs. direct EECP effects (diastolic augmentation, DA-ratio), and their relation to cardiac index (CI) during EECP are unknown. We studied eight patients with angina pectoris (median [range] age 72 [53-85], 25% women), who underwent EECP for 35 daily sessions. Before, during and after the first and last sessions, we assessed VO 2 , DA-ratio and CI. At first EECP, CI increased from 2.2 (1.7-2.9) L/min/m 2 prior to EECP to 3.0 (2.2-3.8) during EECP (p=0.011), and returned to 2.4 (0.8-3.0). Similarly, VO 2 increased during EECP and returned to baseline after EECP. These patterns were reproduced at the last EECP session. Absolute values of CI and VO 2 correlated with each other during but not prior to or after EECP. The increase in CI correlated with the increase in VO 2 by trend: (first session, r 0.52, p=0.19; second session r 0.69, p=0.09), but not with DA-ratio. Acutely during EECP, there is an increase in cardiac output that is unrelated to direct EECP effects but related to, and may be secondary to, an increase in peripheral O 2 demand. This may represent a training effect. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Overestimation of low cardiac output measured by thermodilution.

PubMed

Tournadre, J P; Chassard, D; Muchada, R

1997-10-01

We have investigated the influence of a cold water bolus (CWB) injection on overestimation of cardiac output (CO) in low CO states in anaesthetized dogs. CO was measured using three methods: (1) thermodilution (TD), (2) electromagnetic (EM) flow meter placed on the pulmonary artery and (3) transoesophageal echo-Doppler (OD) placed on the descending aorta. Measurements of CO were obtained before (steady state) and after induction of a low CO state with thiopentone 5 mg kg-1 i.v. After CWB injection, mean CO measured by EM and OD increased by 26% and 27%, respectively (P < 0.05) during steady state, and by 85% and 75% (P < 0.05) during the low CO state. This transient increase was produced by an increase in stroke volume, while heart rate did not change. Frank Starling's law may explain this variation by a sudden increase in preload produced by CWB injection. These results indicate that thermodilution overestimated CO during low CO states when CWB injection was used.

Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners

PubMed Central

Billat, Véronique L.; Petot, Hélène; Landrain, Morgan; Meilland, Renaud; Koralsztein, Jean Pierre; Mille-Hamard, Laurence

2012-01-01

Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). Methods. We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3 hr 30 min ± 45 min). Results. Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively). Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO × m−1) (r = −0.65, P < 0.01) and positively correlated with the runner's ability to complete the race at a high percentage of the speed at maximal SV (r = 0.83, P < 0.0002). Conclusion. Our results showed that marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners. PMID:22645458

Improved Accuracy of Automated Estimation of Cardiac Output Using Circulation Time in Patients with Heart Failure.

PubMed

Dajani, Hilmi R; Hosokawa, Kazuya; Ando, Shin-Ichi

2016-11-01

Lung-to-finger circulation time of oxygenated blood during nocturnal periodic breathing in heart failure patients measured using polysomnography correlates negatively with cardiac function but possesses limited accuracy for cardiac output (CO) estimation. CO was recalculated from lung-to-finger circulation time using a multivariable linear model with information on age and average overnight heart rate in 25 patients who underwent evaluation of heart failure. The multivariable model decreased the percentage error to 22.3% relative to invasive CO measured during cardiac catheterization. This improved automated noninvasive CO estimation using multiple variables meets a recently proposed performance criterion for clinical acceptability of noninvasive CO estimation, and compares very favorably with other available methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantification of mitral regurgitation by automated cardiac output measurement: experimental and clinical validation

NASA Technical Reports Server (NTRS)

Sun, J. P.; Yang, X. S.; Qin, J. X.; Greenberg, N. L.; Zhou, J.; Vazquez, C. J.; Griffin, B. P.; Stewart, W. J.; Thomas, J. D.

1998-01-01

OBJECTIVES: To develop and validate an automated noninvasive method to quantify mitral regurgitation. BACKGROUND: Automated cardiac output measurement (ACM), which integrates digital color Doppler velocities in space and in time, has been validated for the left ventricular (LV) outflow tract but has not been tested for the LV inflow tract or to assess mitral regurgitation (MR). METHODS: First, to validate ACM against a gold standard (ultrasonic flow meter), 8 dogs were studied at 40 different stages of cardiac output (CO). Second, to compare ACM to the LV outflow (ACMa) and inflow (ACMm) tracts, 50 normal volunteers without MR or aortic regurgitation (44+/-5 years, 31 male) were studied. Third, to compare ACM with the standard pulsed Doppler-two-dimensional echocardiographic (PD-2D) method for quantification of MR, 51 patients (61+/-14 years, 30 male) with MR were studied. RESULTS: In the canine studies, CO by ACM (1.32+/-0.3 liter/min, y) and flow meter (1.35+/-0.3 liter/min, x) showed good correlation (r=0.95, y=0.89x+0.11) and agreement (deltaCO(y-x)=0.03+/-0.08 [mean+/-SD] liter/min). In the normal subjects, CO measured by ACMm agreed with CO by ACMa (r=0.90, p < 0.0001, deltaCO=-0.09+/-0.42 liter/min), PD (r=0.87, p < 0.0001, deltaCO=0.12+/-0.49 liter/min) and 2D (r=0.84, p < 0.0001, deltaCO=-0.16+/-0.48 liter/min). In the patients, mitral regurgitant volume (MRV) by ACMm-ACMa agreed with PD-2D (r= 0.88, y=0.88x+6.6, p < 0.0001, deltaMRV=2.68+/-9.7 ml). CONCLUSIONS: We determined that ACM is a feasible new method for quantifying LV outflow and inflow volume to measure MRV and that ACM automatically performs calculations that are equivalent to more time-consuming Doppler and 2D measurements. Additionally, ACM should improve MR quantification in routine clinical practice.

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

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

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.

Validation of an ultrasound dilution technology for cardiac output measurement and shunt detection in infants and children.

PubMed

Lindberg, Lars; Johansson, Sune; Perez-de-Sa, Valeria

2014-02-01

To validate cardiac output measurements by ultrasound dilution technology (COstatus monitor) against those obtained by a transit-time ultrasound technology with a perivascular flow probe and to investigate ultrasound dilution ability to estimate pulmonary to systemic blood flow ratio in children. Prospective observational clinical trial. Pediatric cardiac operating theater in a university hospital. In 21 children (6.1 ± 2.6 kg, mean ± SD) undergoing heart surgery, cardiac output was simultaneously recorded by ultrasound dilution (extracorporeal arteriovenous loop connected to existing arterial and central venous catheters) and a transit-time ultrasound probe applied to the ascending aorta, and when possible, the main pulmonary artery. The pulmonary to systemic blood flow ratio estimated from ultrasound dilution curve analysis was compared with that estimated from transit-time ultrasound technology. Bland-Altman analysis of the whole cohort (90 pairs, before and after surgery) showed a bias between transit-time ultrasound (1.01 ± 0.47 L/min) and ultrasound dilution technology (1.03 ± 0.51 L/min) of -0.02 L/min, limits of agreement -0.3 to 0.3 L/min, and percentage error of 31%. In children with no residual shunts, the bias was -0.04 L/min, limits of agreement -0.28 to 0.2 L/min, and percentage error 19%. The pooled co efficient of variation was for the whole cohort 3.5% (transit-time ultrasound) and 6.3% (ultrasound dilution), and in children without shunt, it was 2.9% (transit-time ultrasound) and 4% (ultrasound dilution), respectively. Ultrasound dilution identified the presence of shunts (pulmonary to systemic blood flow ≠ 1) with a sensitivity of 100% and a specificity of 92%. Mean pulmonary to systemic blood flow ratio by transit-time ultrasound was 2.6 ± 1.0 and by ultrasound dilution 2.2 ± 0.7 (not significant). The COstatus monitor is a reliable technique to measure cardiac output in children with high sensitivity and specificity for detecting the

The accuracy of PiCCO® in measuring cardiac output in patients under therapeutic hypothermia: Comparison with transthoracic echocardiography.

PubMed

Souto Moura, T; Aguiar Rosa, S; Germano, N; Cavaco, R; Sequeira, T; Alves, M; Papoila, A L; Bento, L

2018-03-01

Invasive cardiac monitoring using thermodilution methods such as PiCCO® is widely used in critically ill patients and provides a wide range of hemodynamic variables, including cardiac output (CO). However, in post-cardiac arrest patients subjected to therapeutic hypothermia, the low body temperature possibly could interfere with the technique. Transthoracic Doppler echocardiography (ECHO) has long proved its accuracy in estimating CO, and is not influenced by temperature changes. To assess the accuracy of PiCCO® in measuring CO in patients under therapeutic hypothermia, compared with ECHO. Thirty paired COECHO/COPiCCO measurements were analyzed in 15 patients subjected to hypothermia after cardiac arrest. Eighteen paired measurements were obtained at under 36°C and 12 at ≥36°C. A value of 0.5l/min was considered the maximum accepted difference between the COECHO and COPiCCO values. Under conditions of normothermia (≥36°C), the mean difference between COECHO and COPiCCO was 0.030 l/min, with limits of agreement (-0.22, 0.28) - all of the measurements differing by less than 0.5 l/min. In situations of hypothermia (<36°C), the mean difference in CO measurements was -0.426 l/min, with limits of agreement (-1.60, 0.75), and only 44% (8/18) of the paired measurements fell within the interval (-0.5, 0.5). The calculated temperature cut-off point maximizing specificity was 35.95°C: above this temperature, specificity was 100%, with a false-positive rate of 0%. The results clearly show clinically relevant discordance between COECHO and COPiCCO at temperatures of <36°C, demonstrating the inaccuracy of PiCCO® for cardiac output measurements in hypothermic patients. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Cardiac output by pulse contour analysis does not match the increase measured by rebreathing during human spaceflight.

PubMed

Hughson, Richard L; Peterson, Sean D; Yee, Nicholas J; Greaves, Danielle K

2017-11-01

Pulse contour analysis of the noninvasive finger arterial pressure waveform provides a convenient means to estimate cardiac output (Q̇). The method has been compared with standard methods under a range of conditions but never before during spaceflight. We compared pulse contour analysis with the Modelflow algorithm to estimates of Q̇ obtained by rebreathing during preflight baseline testing and during the final month of long-duration spaceflight in nine healthy male astronauts. By Modelflow analysis, stroke volume was greater in supine baseline than seated baseline or inflight. Heart rate was reduced in supine baseline so that there were no differences in Q̇ by Modelflow estimate between the supine (7.02 ± 1.31 l/min, means ± SD), seated (6.60 ± 1.95 l/min), or inflight (5.91 ± 1.15 l/min) conditions. In contrast, rebreathing estimates of Q̇ increased from seated baseline (4.76 ± 0.67 l/min) to inflight (7.00 ± 1.39 l/min, significant interaction effect of method and spaceflight, P < 0.001). Pulse contour analysis utilizes a three-element Windkessel model that incorporates parameters dependent on aortic pressure-area relationships that are assumed to represent the entire circulation. We propose that a large increase in vascular compliance in the splanchnic circulation invalidates the model under conditions of spaceflight. Future spaceflight research measuring cardiac function needs to consider this important limitation for assessing absolute values of Q̇ and stroke volume. NEW & NOTEWORTHY Noninvasive assessment of cardiac function during human spaceflight is an important tool to monitor astronaut health. This study demonstrated that pulse contour analysis of finger arterial blood pressure to estimate cardiac output failed to track the 46% increase measured by a rebreathing method. These results strongly suggest that alternative methods not dependent on pulse contour analysis are required to track cardiac function in spaceflight

Significant correlation of comprehensive Aristotle score with total cardiac output during the early postoperative period after the Norwood procedure.

PubMed

Li, Jia; Zhang, Gencheng; Holtby, Helen; Cai, Sally; Walsh, Mark; Caldarone, Christopher A; Van Arsdell, Glen S

2008-07-01

The comprehensive Aristotle score has been proposed as an individualized measure of the complexity of a given surgical procedure and has been reported to significantly correlate with postoperative morbidity and mortality after the Norwood procedure. An important factor leading to postoperative morbidity and mortality is low cardiac output. We studied the correlation between the comprehensive Aristotle score and cardiac output (CO) in infants after the Norwood procedure. Respiratory mass spectrometry was used to continuously measure systemic oxygen consumption (VO(2)) in 22 infants for 72 hours postoperatively. Arterial, superior vena caval and pulmonary venous blood gases were measured at 2 to 4 hour intervals to calculate CO. The comprehensive Aristotle score was collected. Hospital mortality was 4.5%. The comprehensive Aristotle score ranged from 14.5 to 23.5 and negatively correlated with CO (P = 0.027). Among the patient-adjusted factors, myocardial dysfunction (n = 10), mechanical ventilation to treat cardiorespiratory failure (n = 9) and atrioventricular valve regurgitation (n = 4) (P = 0.01) negatively correlated with CO (P = 0.06 to 0.07). Aortic atresia (n = 9) was associated with a lower CO (P = 0.01) for the first 24 hours which linearly increased overtime (P = 0.0001). No correlation was found between CO and other factors (P > 0.3 for all). Comprehensive Aristotle score significantly negatively correlates with CO after the Norwood procedure. A preoperative estimation of the comprehensive Aristotle score, particularly in association with myocardial dysfunction, mechanical ventilation to treat cardiorespiratory failure, atrioventricular valve regurgitation and aortic atresia may help to anticipate a high postoperative morbidity with low cardiac output syndrome.

Low cardiac output syndrome in the postoperative period of cardiac surgery. Profile, differences in clinical course and prognosis. The ESBAGA study.

PubMed

Pérez Vela, J L; Jiménez Rivera, J J; Alcalá Llorente, M Á; González de Marcos, B; Torrado, H; García Laborda, C; Fernández Zamora, M D; González Fernández, F J; Martín Benítez, J C

2018-04-01

An analysis is made of the clinical profile, evolution and differences in morbidity and mortality of low cardiac output syndrome (LCOS) in the postoperative period of cardiac surgery, according to the 3 diagnostic subgroups defined by the SEMICYUC Consensus 2012. A multicenter, prospective cohort study was carried out. ICUs of Spanish hospitals with cardiac surgery. A consecutive sample of 2,070 cardiac surgery patients was included, with the analysis of 137 patients with LCOS. No intervention was carried out. The mean patient age was 68.3±9.3 years (65.2% males), with a EuroSCORE II of 9.99±13. NYHA functional class III-IV (52.9%), left ventricular ejection fraction<35% (33.6%), AMI (31.9%), severe PHT (21.7%), critical preoperative condition (18.8%), prior cardiac surgery (18.1%), PTCA/stent placement (16.7%). According to subgroups, 46 patients fulfilled hemodynamic criteria of LCOS (group A), 50 clinical criteria (group B), and the rest (n=41) presented cardiogenic shock (group C). Significant differences were observed over the evolutive course between the subgroups in terms of time subjected to mechanical ventilation (114.4, 135.4 and 180.3min in groups A, B and C, respectively; P<.001), renal replacement requirements (11.4, 14.6 and 36.6%; P=.007), multiorgan failure (16.7, 13 and 47.5%), and mortality (13.6, 12.5 and 35.9%; P=.01). The mean maximum lactate concentration was higher in cardiogenic shock patients (P=.002). The clinical evolution of these patients leads to high morbidity and mortality. We found differences between the subgroups in terms of the postoperative clinical course and mortality. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Noninvasive continuous cardiac output by the Nexfin before and after preload-modifying maneuvers: a comparison with intermittent thermodilution cardiac output.

PubMed

Bubenek-Turconi, Serban Ion; Craciun, Mihaela; Miclea, Ion; Perel, Azriel

2013-08-01

The Nexfin uses an uncalibrated pulse contour method for the continuous measurement of cardiac output (CO) in a totally noninvasive manner. Since the accuracy of pulse contour methods and their ability to track changes in CO have been repeatedly questioned, we have compared the CO measured by the Nexfin (NAPCO) with the CO measured by the pulmonary artery catheter (PACCO) in cardiosurgical patients before and after preload-modifying maneuvers. Twenty-eight patients who underwent on-pump cardiac surgery, of whom 18 were receiving vasopressor and/or inotropic therapy, were studied during the first postoperative hours. Preload modification, in the form of either a fluid challenge or a passive leg raising maneuver, was done whenever clinically indicated, with PACCO and NAPCO being simultaneously measured before and after each intervention. A fluid challenge was administered to 22 patients, and the passive leg raising maneuver was performed in 6 patients. These interventions were repeated in 19 patients producing a total of 47 pairs of measurements. At baseline, mean (±SD) CO was 4.9 ± 1.1 and 5.0 ± 1.4 L·min(-1), for the PACCO and NAPCO, respectively, bias 0.1 ± 1.0, 95% prediction interval -2.5 to 2.4 L·min(-1), and 39% of error. After preload modification, the mean CO was 5.6 ± 1.3 and 5.6± 1.5 L·min(-1) for the PACCO and NAPCO, respectively, bias -0.0 ± 1.1, 95% prediction interval -2.6 to 2.7 L·min(-1), and 38% of error. The correlation coefficients (r) between the PACCO and NAPCO before and after preload modification were 0.71 (95% confidence interval [95% CI], 0.53-0.82) and 0.70 (95% CI, 0.52-0.82), respectively. Preload modification induced similar absolute changes in PACCO and NAPCO (r = 0.9, P < 0.0001). A 4-quadrant scatter plot showed a concordance rate of 100% (95% CI, 80.5%-100%) between the changes in NAPCO and PACCO. Polar plot analysis demonstrated a small polar angle and radial limits of agreement well below the 30° benchmark. The area

Preferential cephalic redistribution of left ventricular cardiac output during therapeutic hypothermia for perinatal hypoxic-ischemic encephalopathy

PubMed Central

Hochwald, Ori; Jabr, Mohammed; Osiovich, Horacio; Miller, Steven P.; McNamara, Patrick J.; Lavoie, Pascal M.

2015-01-01

Objective To determine the relationship between left ventricular cardiac output (LVCO), superior vena cava (SVC) flow, and brain injury during whole-body therapeutic hypothermia. Study design Sixteen newborns with moderate or severe hypoxic-ischemic encephalopathy were studied using echocardiography during and immediately after therapeutic hypothermia. Measures were also compared with 12 healthy newborns of similar postnatal age. Newborns undergoing therapeutic hypothermia also had a cerebral magnetic resonance imaging as part of routine clinical care on postnatal day 3–4. Results LVCO was markedly reduced (mean+/−SD: 126+/−38 mL/kg/min) during therapeutic hypothermia, whereas SVC flow was maintained within expected normal values (88+/− 27 mL/kg/min) such that it represented 70% of the LVCO. The reduction in LVCO during therapeutic hypothermia was mainly accounted by a reduction in heart rate (99 +/− 13 BPM versus 123 +/− 17 BPM; p<0.001) compared to immediately post-warming, in the context of myocardial dysfunction. Neonates with documented brain injury on MRI showed higher SVC flow pre-rewarming, compared to newborns without brain injury (p=0.013). Conclusion Newborns with perinatal hypoxic-ischemic encephalopathy showed a preferential systemic-to cerebral redistribution of cardiac blood flow during whole-body therapeutic hypothermia, which may reflect a lack of cerebral vascular adaptation in newborns with more severe brain injury. PMID:24582011

Preferential cephalic redistribution of left ventricular cardiac output during therapeutic hypothermia for perinatal hypoxic-ischemic encephalopathy.

PubMed

Hochwald, Ori; Jabr, Mohammad; Osiovich, Horacio; Miller, Steven P; McNamara, Patrick J; Lavoie, Pascal M

2014-05-01

To determine the relationship between left ventricular cardiac output (LVCO), superior vena cava (SVC) flow, and brain injury during whole-body therapeutic hypothermia. Sixteen newborns with moderate or severe hypoxic-ischemic encephalopathy were studied using echocardiography during and immediately after therapeutic hypothermia. Measures were also compared with 12 healthy newborns of similar postnatal age. Newborns undergoing therapeutic hypothermia also had cerebral magnetic resonance imaging as part of routine clinical care on postnatal day 3-4. LVCO was markedly reduced (mean ± SD 126 ± 38 mL/kg/min) during therapeutic hypothermia, whereas SVC flow was maintained within expected normal values (88 ± 27 mL/kg/min) such that SVC flow represented 70% of the LVCO. The reduction in LVCO during therapeutic hypothermia was mainly accounted by a reduction in heart rate (99 ± 13 vs 123 ± 17 beats/min; P < .001) compared with immediately postwarming in the context of myocardial dysfunction. Neonates with brain injury on magnetic resonance imaging had higher SVC flow prerewarming, compared with newborns without brain injury (P = .013). Newborns with perinatal hypoxic-ischemic encephalopathy showed a preferential systemic-to-cerebral redistribution of cardiac blood flow during whole-body therapeutic hypothermia, which may reflect a lack of cerebral vascular adaptation in newborns with more severe brain injury. Copyright © 2014 Elsevier Inc. All rights reserved.

Decrease of Total Antioxidative Capacity in Developed Low Cardiac Output Syndrome

PubMed Central

Kunt, Alper Sami; Andac, Mehmet Halit

2012-01-01

Background. It has been known that cardiac surgery induces an oxidative stress. The persistent oxidative stress during reperfusion may lead to depressed myocardial function resulting in low cardiac output syndrome (LCOS) necessitating inotropic or intra-aortic balloon counterpulsation support. Total antioxidant capacity (TAC) is a measurement of oxidative stress in tissues. The purpose of this study was to examine the TAC differences during coronary artery bypass graft (CABG) operation in patients who have developed LCOS and who have not. Material and Methods. Seventy-nine patients were enrolled in the study. Central venous blood samples were obtained immediately before surgery, during operation, and at the end of surgery to assess TAC. Clinical data regarding patient demographics and operative outcomes were prospectively collected and entered into our clinical database. Results. LCOS developed in 8 patients (10.12%). The TAC has decreased sharply in the LCOS patients compared with those who did not develop LCOS (P < 0.001) during operation. In addition, the receiver operating characteristic (ROC) area was 0.879. Conclusion. TAC has decreased during operation in a significant proportion of patients undergoing isolated CABG, and this is more prominent and serious and might be an independent variable in patients who have developed LCOS. This may be related to intraoperative misadventure or inadequate myocardial antioxidative protection. Routine measurement of the TAC during operation may provide information for assessment of the LCOS development. PMID:23251720

Simultaneous determination of dynamic cardiac metabolism and function using PET/MRI.

PubMed

Barton, Gregory P; Vildberg, Lauren; Goss, Kara; Aggarwal, Niti; Eldridge, Marlowe; McMillan, Alan B

2018-05-01

Cardiac metabolic changes in heart disease precede overt contractile dysfunction. However, metabolism and function are not typically assessed together in clinical practice. The purpose of this study was to develop a cardiac positron emission tomography/magnetic resonance (PET/MR) stress test to assess the dynamic relationship between contractile function and metabolism in a preclinical model. Following an overnight fast, healthy pigs (45-50 kg) were anesthetized and mechanically ventilated. 18 F-fluorodeoxyglucose ( 18 F-FDG) solution was administered intravenously at a constant rate of 0.01 mL/s for 60 minutes. A cardiac PET/MR stress test was performed using normoxic gas (F I O 2  = .209) and hypoxic gas (F I O 2  = .12). Simultaneous cardiac imaging was performed on an integrated 3T PET/MR scanner. Hypoxic stress induced a significant increase in heart rate, cardiac output, left ventricular (LV) ejection fraction (EF), and peak torsion. There was a significant decline in arterial SpO 2 , LV end-diastolic and end-systolic volumes in hypoxia. Increased LV systolic function was coupled with an increase in myocardial FDG uptake (Ki) during hypoxic stress. PET/MR with continuous FDG infusion captures dynamic changes in both cardiac metabolism and contractile function. This technique warrants evaluation in human cardiac disease for assessment of subtle functional and metabolic abnormalities.

Prophylactic levosimendan for the prevention of low cardiac output syndrome and mortality in paediatric patients undergoing surgery for congenital heart disease.

PubMed

Hummel, Johanna; Rücker, Gerta; Stiller, Brigitte

2017-08-02

Low cardiac output syndrome remains a serious complication, and accounts for substantial morbidity and mortality in the postoperative course of paediatric patients undergoing surgery for congenital heart disease. Standard prophylactic and therapeutic strategies for low cardiac output syndrome are based mainly on catecholamines, which are effective drugs, but have considerable side effects. Levosimendan, a calcium sensitiser, enhances the myocardial function by generating more energy-efficient myocardial contractility than achieved via adrenergic stimulation with catecholamines. Thus potentially, levosimendan is a beneficial alternative to standard medication for the prevention of low cardiac output syndrome in paediatric patients after open heart surgery. To review the efficacy and safety of the postoperative prophylactic use of levosimendan for the prevention of low cardiac output syndrome and mortality in paediatric patients undergoing surgery for congenital heart disease. We identified trials via systematic searches of CENTRAL, MEDLINE, Embase, and Web of Science, as well as clinical trial registries, in June 2016. Reference lists from primary studies and review articles were checked for additional references. We only included randomised controlled trials (RCT) in our analysis that compared prophylactic levosimendan with standard medication or placebo, in infants and children up to 18 years of age, who were undergoing surgery for congenital heart disease. Two review authors independently extracted data and assessed risk of bias according to a pre-defined protocol. We obtained additional information from all but one of the study authors of the included studies. We used the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness, and publication bias) to assess the quality of evidence from the studies that contributed data to the meta-analyses for the prespecified outcomes. We created a 'Summary of findings' table to

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

NASA Astrophysics Data System (ADS)

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

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

Validation of cardiac output using real-time measurement of oxygen consumption during cardiac catheterization in children under 3 years of age.

PubMed

Seckeler, Michael D; Hirsch, Russel; Beekman, Robert H; Goldstein, Bryan H

2014-01-01

To validate a method for determination of cardiac index (CI) using real-time measurement of oxygen consumption (VO2 ) in young children undergoing cardiac catheterization. Retrospective review comparing thermodilution cardiac index (TDCI) to CI calculated by the Fick equation using real-time measured VO2 (RT-VO2 ) and VO2 derived from 2 published predictive equations. Paired t-test and Bland-Altman analysis were used to compare TDCI to Fick CI. A survey to ascertain pediatric cardiac catheterization practices regarding VO2 determination was also conducted. Quaternary care children's hospital cardiac catheterization laboratory. Children <3 years old with structurally normal hearts undergoing cardiac catheterization under general anesthesia with at least one set of contemporaneous TDCI and RT-VO2 measurements. Thirty-six paired measurements of TDCI and RT-VO2 were made in 27 patients over a 2-year period. Indications for catheterization included congenital diaphragmatic hernia postrepair (n = 13), heart disease post-orthotopic heart transplant (n = 13), and suspected cardiomyopathy (n = 1). Mean age was 21.5 ± 8 months; median weight was 9.9 kg (IQR 8.57, 12.2). RT-VO2 was higher than VO2 predicted by the LaFarge equation (190 ± 31 vs. 173.8 ± 12.8 mL/min/m(2), P < .001), but there was no difference between TDCI and Fick CI calculated using VO2 from any method. Bland-Altman analysis showed excellent agreement between TDCI and Fick CI using RT-VO2 and VO2 predicted by the Lundell equation; Fick CI using VO2 predicted by the LaFarge equation showed fair agreement with TDCI. In children <3 years with a structurally normal heart, RT-VO2 generates highly accurate determinations of Fick CI as compared with TDCI. Additionally, in this population, VO2 derived from the LaFarge and Lundell equations generates accurate Fick CI compared with TDCI. Future studies are needed to identify factors associated with inaccurate VO2 generated from these predictive equations. © 2013

Three-dimensional cardiac architecture determined by two-photon microtomy

NASA Astrophysics Data System (ADS)

Huang, Hayden; MacGillivray, Catherine; Kwon, Hyuk-Sang; Lammerding, Jan; Robbins, Jeffrey; Lee, Richard T.; So, Peter

2009-07-01

Cardiac architecture is inherently three-dimensional, yet most characterizations rely on two-dimensional histological slices or dissociated cells, which remove the native geometry of the heart. We previously developed a method for labeling intact heart sections without dissociation and imaging large volumes while preserving their three-dimensional structure. We further refine this method to permit quantitative analysis of imaged sections. After data acquisition, these sections are assembled using image-processing tools, and qualitative and quantitative information is extracted. By examining the reconstructed cardiac blocks, one can observe end-to-end adjacent cardiac myocytes (cardiac strands) changing cross-sectional geometries, merging and separating from other strands. Quantitatively, representative cross-sectional areas typically used for determining hypertrophy omit the three-dimensional component; we show that taking orientation into account can significantly alter the analysis. Using fast-Fourier transform analysis, we analyze the gross organization of cardiac strands in three dimensions. By characterizing cardiac structure in three dimensions, we are able to determine that the α crystallin mutation leads to hypertrophy with cross-sectional area increases, but not necessarily via changes in fiber orientation distribution.

Nasal continuous positive airway pressure (n-CPAP) does not change cardiac output in preterm infants.

PubMed

Moritz, Barbara; Fritz, Michael; Mann, Christian; Simma, Burkhard

2008-02-01

Our objective was to study how invasive mechanical ventilation impairs cardiac output (CO) in children and adults. Although the application of continuous positive airway pressure (CPAP) is widely practiced in neonatal intensive care, its hemodynamic consequences have not yet been investigated. A prospective study to assess the hemodynamic effects was conducted in 21 preterm infants < 1500 g using two-dimensional M-mode and pulsed Doppler echocardiography during and 1 hour after discontinuation of nasal CPAP (n-CPAP). Gestational age was 28.0 +/- 1.9 weeks (mean +/- standard deviation); birthweight, 1000 +/- 238 g; age at study entry, 200 +/- 155 hours; total maintenance fluid, 154 +/- 42 mL/kg/day; and n-CPAP level, 4.4 +/- 0.9 cm H(2)O. None of the infants received inotropic support, and n-CPAP did not cause any significant difference in the parameters measured: stroke volume, 3.1 +/- 1.0 mL (with n-CPAP) versus 3.1 +/- 1.0 mL (without n-CPAP); cardiac output, 487 +/- 156 mL/minute versus 500 +/- 176 mL/minute; left ventricular diastolic diameter, 1.22 +/- 0.15 cm versus 1.24 +/- 0.14 cm; fractional shortening, 0.30 +/- 0.05% versus 0.29 +/- 0.04%; and aortic velocity-time integral, 8.64 +/- 1.80 cm versus 8.70 +/- 1.65 cm. The n-CPAP level did not influence CO; n-CPAP (up to 7 cm H (2)O) has no echocardiographically detectable hemodynamic effect in preterm infants. Our data imply there is no need to withhold n-CPAP support to prevent circulatory compromise in these infants.

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

PubMed

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

2014-03-01

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. 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). In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.

Indexation of cardiac output to biometric parameters in critically ill patients: A systematic analysis of a transpulmonary thermodilution-derived database.

PubMed

Saugel, Bernd; Mair, Sebastian; Götz, Simon Q; Tschirdewahn, Julia; Frank, Johanna; Höllthaler, Josef; Schmid, Roland M; Huber, Wolfgang

2015-10-01

Cardiac output (CO) (liters per minute) is usually normalized (ie, indexed) to the patient's body surface area (BSA) resulting in the hemodynamic variable cardiac index (CI) (liters per minute per square meter). We aimed (1) to evaluate the impact of different body weight-based CO indexations on the resulting CI values and (2) to identify biometric parameters independently associated with CO in critically ill patients. The study is an analysis of a database containing transpulmonary thermodilution-derived hemodynamic variables of 234 medical intensive care unit patients. Cardiac index indexed to actual BSA was statistically significantly lower compared with CI indexed to predicted BSA in the totality of patients and in the subgroups of patients with body mass index greater than or equal to 25 kg/m(2) but less than 30 kg/m(2) and body mass index greater than or equal to 30 kg/m(2) (with a statistically significant difference in the proportion of low and high CI measurements). Multivariate analysis of the first CO measurement of each patient demonstrated that CO was independently associated with age (P < .001), height (P = .001), and actual body weight (BWact) (P = .030). Multivariate analysis of the mean of the patients' CO measurements confirmed age (P < .001), height (P = .001), and BWact (P < .001) as biometric factors independently associated with CO. Age was identified as the most important factor with each year of age decreasing CO by 66 mL/min (95% confidence interval, 47-86 mL/min). The indexation of CO to BSA is highly dependent on the body weight estimation formula used to calculate BSA. Cardiac output is independently associated with the biometric factors age, height, and BWact. These factors might be considered for indexation of CO. Copyright © 2015 Elsevier Inc. All rights reserved.

Oral Consumption of Vitamin K2 for 8 Weeks Associated With Increased Maximal Cardiac Output During Exercise.

PubMed

McFarlin, Brian K; Henning, Andrea L; Venable, Adam S

2017-07-01

Background • Vitamin K1 and K2 are not typically common in a Western diet because they are found in a variety of fermented foods. Vitamin K2 in particular has been demonstrated to restore mitochondrial function and has a key role in production of mitochondrial adenosine triphosphate. Thus, it is reasonable to speculate that dietary supplementation with vitamin K2 could increase the function of muscle with high mitochondrial content (ie, skeletal and cardiac muscle). Objective • The purpose of this study was to determine if 8 wk of dietary supplementation with Vitamin K2 could alter cardiovascular responses to a graded cycle ergometer test. Design • The study was a randomized controlled trial. Setting • The study took place in the Applied Physiology Laboratory of the Department of Biological Sciences at the University of North Texas (Denton, TX, USA). Participants • Participants were aerobically trained males and female athletes (N = 26). Intervention • Participants were randomly assigned either to a control group that received a rice flour placebo or to an intervention group that received vitamin K2. For weeks 1 to 4, participants received 300 mg/d; for weeks 5 to 8, they received 150 mg/d. Subjects assigned to the control group received similar doses to mirror the intervention group. Subjects consumed the supplements during an 8-wk period while they maintained their typical exercise habits. Outcome Measures • At baseline and postintervention, participants completed a standard, graded exercise test on an electronically braked cycle ergometer. Before the test, participants were fitted with a mouth piece, and their oxygen consumption, carbon dioxide production, respiratory rate, and respiratory exchange ratio were measured. In addition, participants were fitted with skin-mounted electrodes that measured noninvasive cardiac output, stroke volume, and heart rate. To assess the cumulative exercise change, an area-under-the-curve (AUC) value was calculated

Recent advances in and limitations of cardiac output monitoring by means of electrical impedance tomography.

PubMed

Pikkemaat, Robert; Lundin, Stefan; Stenqvist, Ola; Hilgers, Ralf-Dieter; Leonhardt, Steffen

2014-07-01

Currently, the monitoring of cardiac output (CO) and stroke volume (SV) is mainly performed using invasive techniques. Therefore, performing CO monitoring noninvasively by means of electrical impedance tomography (EIT) would be advantageous for intensive care. Our hypothesis was that, by means of EIT, it is possible to assess heart rate (HR) and to quantify changes in SV due to changes in ventilator settings. CO (HR and SV) of 14 pigs (32-40 kg body weight) was changed by incremental increases in positive end-expiratory pressure levels (0, 5, 10, 15, and 20 cm·H2O; ramp maneuver). This ramp maneuver was applied 4 times in each animal, yielding 43 evaluable single experiments. At each positive end-expiratory pressure level, SV was assessed by transpulmonary thermodilution using a PiCCO device. EIT data were acquired using a Dräger EIT Evaluation Kit 2. The EIT-based SV-related signal, Z(SV) (in [AU]), showed only a weak correlation (after excluding 2 measurements) with SV(TTD) of r = 0.58 (95% confidence interval, 0.43-0.71). If Z(SV) is calibrated by the reference 1 time for each experiment (defined as SVEIT), the correlation is approximately 0.85 (95% confidence interval, 0.78-0.90). A possible reason for the moderate correlation is the unexpected scaling pattern, leading to amplification of the cardiac impedance signal, found in some animals. The scaling is probably due to the imperfect reconstruction (i.e., a change of sensitivity) of the EIT images or to a change in the position of the heart. The hypothesis that EIT can be used to monitor CO and SV was confirmed, but further studies are required before this technique can be applied in clinical practice. HR was determined robustly and accurately. For SV monitoring, promising results were obtained in 80% of the experiments. However, unexpected scaling of the cardiac EIT signal causing inaccurate estimation of SV remains an issue. Before robust assessment of SV by EIT is suitable for clinical practice, the cause

Effects of CGS 21680, a selective A2A adenosine receptor agonist, on cardiac output and vascular resistance in acute heart failure in the anaesthetized rat

PubMed Central

Nekooeian, Ali A; Tabrizchi, Reza

1998-01-01

The effects of CGS 21680, a selective A2A adenosine receptor agonist, on cardiac output, blood pressure, mean circulatory filling pressure (Pmcf), arterial and venous resistances, heart rate and left ventricular end-diastolic pressure were assessed in rats with acute heart failure by means of coronary artery occlusion.Animals (n=6 in each group) were divided into five groups: group I, sham-operated vehicle-treated (0.9% saline; 0.018 mL min−1); groups II-V, subject to coronary artery occlusion and treated with vehicle (0.9% saline; 0.018 ml min−1) and CGS 21680 (0.1, 0.3 and 1.0 μg kg−1 min−1), respectively. Haemodynamic measurements were taken one hour after completion of surgery, ninety minutes after coronary artery occlusion (except in group I), and fifteen minutes after infusion of saline or CGS 21680.Baseline haemodynamic measurements before occlusion were found not to differ significantly between the different groups of animals. However, after occlusion, cardiac output, rate of rise in left ventricular pressure (+dP/dt) and blood pressure were significantly reduced when compared to corresponding values in sham-operated animals. In addition, occlusion of the coronary artery resulted in a significant elevation in venous resistance, Pmcf and left ventricular end-diastolic pressure as compared to corresponding values in sham-operated animals.Infusion with CGS 21680 at the highest dose significantly reduced blood pressure, arterial resistance and left ventricular end-diastolic pressure when compared to occluded vehicle-treated animals (group II). Administration of CGS 21680 at the highest dose also significantly increased cardiac output (28%) and heart rate (10%) in comparison to occluded vehicle-treated animals. In addition, the highest dose of CGS 21680 significantly reduced Pmcf (9%) and venous resistance (62%) in comparison to occluded vehicle-treated animals. Administration of CGS 21680 did not significantly affect +dP/dt when compared

Effects of CGS 21680, a selective A2A adenosine receptor agonist, on cardiac output and vascular resistance in acute heart failure in the anaesthetized rat.

PubMed

Nekooeian, A A; Tabrizchi, R

1998-04-01

1. The effects of CGS 21680, a selective A2A adenosine receptor agonist, on cardiac output, blood pressure, mean circulatory filling pressure (Pmcf), arterial and venous resistances, heart rate and left ventricular end-diastolic pressure were assessed in rats with acute heart failure by means of coronary artery occlusion. 2. Animals (n=6 in each group) were divided into five groups: group I, sham-operated vehicle-treated (0.9% saline; 0.018 mL min(-1)); groups II-V, subject to coronary artery occlusion and treated with vehicle (0.9% saline; 0.018 ml min(-1)) and CGS 21680 (0.1, 0.3 and 1.0 microg kg(-1) min(-1)), respectively. Haemodynamic measurements were taken one hour after completion of surgery, ninety minutes after coronary artery occlusion (except in group I), and fifteen minutes after infusion of saline or CGS 21680. 3. Baseline haemodynamic measurements before occlusion were found not to differ significantly between the different groups of animals. However, after occlusion, cardiac output, rate of rise in left ventricular pressure (+ dP/dt) and blood pressure were significantly reduced when compared to corresponding values in sham-operated animals. In addition, occlusion of the coronary artery resulted in a significant elevation in venous resistance, Pmcf and left ventricular end-diastolic pressure as compared to corresponding values in sham-operated animals. 4. Infusion with CGS 21680 at the highest dose significantly reduced blood pressure, arterial resistance and left ventricular end-diastolic pressure when compared to occluded vehicle-treated animals (group II). Administration of CGS 21680 at the highest dose also significantly increased cardiac output (28%) and heart rate (10%) in comparison to occluded vehicle-treated animals. In addition, the highest dose of CGS 21680 significantly reduced Pmcf (9%) and venous resistance (62%) in comparison to occluded vehicle-treated animals. Administration of CGS 21680 did not significantly affect +dP/dt when

External cardiac compression may be harmful in some scenarios of pulseless electrical activity.

PubMed

Hogan, T S

2012-10-01

Pulseless electrical activity occurs when organised or semi-organised electrical activity of the heart persists but the product of systemic vascular resistance and the increase in systemic arterial flow generated by the ejection of the left venticular stroke volume is not sufficient to produce a clinically detectable pulse. Pulseless electrical activity encompasses a very heterogeneous variety of severe circulatory shock states ranging in severity from pseudo-cardiac arrest to effective cardiac arrest. Outcomes of cardiopulmonary resuscitation for pulseless electrical activity are generally poor. Impairment of cardiac filling is the limiting factor to cardiac output in many scenarios of pulseless electrical activity, including extreme vasodilatory shock states. There is no evidence that external cardiac compression can increase cardiac output when impaired cardiac filling is the limiting factor to cardiac output. If impaired cardiac filling is the limiting factor to cardiac output and the heart is effectively ejecting all the blood returning to it, then external cardiac compression can only increase cardiac output if it increases venous return and cardiac filling. Repeated cardiac compression asynchronous with the patient's cardiac cycle and raised mean intrathoracic pressure due to chest compression can be expected to reduce rather than to increase cardiac filling and therefore to reduce rather than to increase cardiac output in such circumstances. The hypothesis is proposed that the performance of external cardiac compression will have zero or negative effect on cardiac output in pulseless electrical activity when impaired cardiac filling is the limiting factor to cardiac output. External cardiac compression may be both directly and indirectly harmful to significant sub-groups of patients with pulseless electrical activity. We have neither evidence nor theory to provide comfort that external cardiac compression is not harmful in many scenarios of pulseless

Determination of the acoustic output of a harmonic scalpel.

PubMed

Koch, Christian; Borys, Michael; Fedtke, Thomas; Richter, Utz; Pöhl, Bernd

2002-11-01

The acoustic output of a harmonic scalpel was experimentally determined, and both the airborne ultrasound and the ultrasound transmitted in water were taken into account. The sound pressure level of airborne ultrasound was measured with a microphone and an artificial head, so that the free-field value and the sound level at the entrance at the bottom of the cavum conchae of the ear could be determined. The derived output power in water was obtained from a hydrophone measurement. The results were strongly influenced by cavitation effects, and it is shown that the power values with and without cavitation differ by more than a factor of 5. The measurement of acoustic output parameters forms the basis for describing the performance of the devices and for an assessment of the risk of harmful bioeffects on both the operator and the patient.

Non-Invasive Monitoring of Cardiac Output in Critical Care Medicine.

PubMed

Nguyen, Lee S; Squara, Pierre

2017-01-01

Critically ill patients require close hemodynamic monitoring to titrate treatment on a regular basis. It allows administering fluid with parsimony and adjusting inotropes and vasoactive drugs when necessary. Although invasive monitoring is considered as the reference method, non-invasive monitoring presents the obvious advantage of being associated with fewer complications, at the expanse of accuracy, precision, and step-response change. A great many methods and devices are now used over the world, and this article focuses on several of them, providing with a brief review of related underlying physical principles and validation articles analysis. Reviewed methods include electrical bioimpedance and bioreactance, respiratory-derived cardiac output (CO) monitoring technique, pulse wave transit time, ultrasound CO monitoring, multimodal algorithmic estimation, and inductance thoracocardiography. Quality criteria with which devices were reviewed included: accuracy (closeness of agreement between a measurement value and a true value of the measured), precision (closeness of agreement between replicate measurements on the same or similar objects under specified conditions), and step response change (delay between physiological change and its indication). Our conclusion is that the offer of non-invasive monitoring has improved in the past few years, even though further developments are needed to provide clinicians with sufficiently accurate devices for routine use, as alternative to invasive monitoring devices.

The Association Between Urine Output, Creatinine Elevation, and Death.

PubMed

Engoren, Milo; Maile, Michael D; Heung, Michael; Jewell, Elizabeth S; Vahabzadeh, Christie; Haft, Jonathan W; Kheterpal, Sachin

2017-04-01

Acute kidney injury can be defined by a fall in urine output, and urine output criteria may be more sensitive in identifying acute kidney injury than traditional serum creatinine criteria. However, as pointed out in the Kidney Disease Improving Global Outcome guidelines, the association of urine output with subsequent creatinine elevations and death is poorly characterized. The purpose of this study was to determine what degrees of reduced urine output are associated with subsequent creatinine elevation and death. This was a retrospective cohort study of adult patients (age ≥18 years) cared for in a cardiovascular intensive care unit after undergoing cardiac operations in a tertiary care university medical center. All adult patients who underwent cardiac operations and were not receiving dialysis preoperatively were studied. The development of acute kidney injury was defined as an increase in creatinine of more than 0.3 mg/dL or by more than 50% above baseline by postoperative day 3. Acute kidney injury developed in 1,061 of 4,195 patients (25%). Urine output had moderate discrimination in predicting subsequent acute kidney injury (C statistic = .637 ± .054). Lower urine output and longer duration of low urine output were associated with greater odds of developing acute kidney injury and death. We found that there is similar accuracy in using urine output corrected for actual, ideal, or adjusted weight to discriminate future acute kidney injury by creatinine elevation and recommend using actual weight for its simplicity. We also found that low urine output is associated with subsequent acute kidney injury and that the association is greater for lower urine output and for low urine output of longer durations. Low urine output (<0.2 mL · kg -1 · h -1 ), even in the absence of acute kidney injury by creatinine elevation, is independently associated with mortality. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights

Effect of Levosimendan on Low Cardiac Output Syndrome in Patients With Low Ejection Fraction Undergoing Coronary Artery Bypass Grafting With Cardiopulmonary Bypass

PubMed Central

Caruba, Thibaut; Grosjean, Sandrine; Amour, Julien; Ouattara, Alexandre; Villacorta, Judith; Miguet, Bertrand; Guinet, Patrick; Lévy, François; Squara, Pierre; Aït Hamou, Nora; Carillon, Aude; Boyer, Julie; Boughenou, Marie-Fazia; Rosier, Sebastien; Robin, Emmanuel; Radutoiu, Mihail; Durand, Michel; Guidon, Catherine; Desebbe, Olivier; Charles-Nelson, Anaïs; Menasché, Philippe; Rozec, Bertrand; Girard, Claude; Fellahi, Jean-Luc; Pirracchio, Romain; Chatellier, Gilles

2017-01-01

Importance Low cardiac output syndrome after cardiac surgery is associated with high morbidity and mortality in patients with impaired left ventricular function. Objective To assess the ability of preoperative levosimendan to prevent postoperative low cardiac output syndrome. Design, Setting, and Participants Randomized, double-blind, placebo-controlled trial conducted in 13 French cardiac surgical centers. Patients with a left ventricular ejection fraction less than or equal to 40% and scheduled for isolated or combined coronary artery bypass grafting with cardiopulmonary bypass were enrolled from June 2013 until May 2015 and followed during 6 months (last follow-up, November 30, 2015). Interventions Patients were assigned to a 24-hour infusion of levosimendan 0.1 µg/kg/min (n = 167) or placebo (n = 168) initiated after anesthetic induction. Main Outcomes and Measures Composite end point reflecting low cardiac output syndrome with need for a catecholamine infusion 48 hours after study drug initiation, need for a left ventricular mechanical assist device or failure to wean from it at 96 hours after study drug initiation when the device was inserted preoperatively, or need for renal replacement therapy at any time postoperatively. It was hypothesized that levosimendan would reduce the incidence of this composite end point by 15% in comparison with placebo. Results Among 336 randomized patients (mean age, 68 years; 16% women), 333 completed the trial. The primary end point occurred in 87 patients (52%) in the levosimendan group and 101 patients (61%) in the placebo group (absolute risk difference taking into account center effect, −7% [95% CI, −17% to 3%]; P = .15). Predefined subgroup analyses found no interaction with ejection fraction less than 30%, type of surgery, and preoperative use of β-blockers, intra-aortic balloon pump, or catecholamines. The prevalence of hypotension (57% vs 48%), atrial fibrillation (50% vs 40%), and other adverse

Assumed oxygen consumption based on calculation from dye dilution cardiac output: an improved formula.

PubMed

Bergstra, A; van Dijk, R B; Hillege, H L; Lie, K I; Mook, G A

1995-05-01

This study was performed because of observed differences between dye dilution cardiac output and the Fick cardiac output, calculated from estimated oxygen consumption according to LaFarge and Miettinen, and to find a better formula for assumed oxygen consumption. In 250 patients who underwent left and right heart catheterization, the oxygen consumption VO2 (ml.min-1) was calculated using Fick's principle. Either pulmonary or systemic flow, as measured by dye dilution, was used in combination with the concordant arteriovenous oxygen concentration difference. In 130 patients, who matched the age of the LaFarge and Miettinen population, the obtained values of oxygen consumption VO2(dd) were compared with the estimated oxygen consumption values VO2(lfm), found using the LaFarge and Miettinen formulae. The VO2(lfm) was significantly lower than VO2(dd); -21.8 +/- 29.3 ml.min-1 (mean +/- SD), P < 0.001, 95% confidence interval (95% CI) -26.9 to -16.7, limits of agreement (LA) -80.4 to 36.9. A new regression formula for the assumed oxygen consumption VO2(ass) was derived in 250 patients by stepwise multiple regression analysis. The VO2(dd) was used as a dependent variable, and body surface area BSA (m2). Sex (0 for female, 1 for male), Age (years), Heart rate (min-1) and the presence of a left to right shunt as independent variables. The best fitting formula is expressed as: VO2(ass) = (157.3 x BSA + 10.0 x Sex - 10.5 x In Age + 4.8) ml.min-1, where ln Age = the natural logarithm of the age. This formula was validated prospectively in 60 patients. A non-significant difference between VO2(ass) and VO2(dd) was found; mean 2.0 +/- 23.4 ml.min-1, P = 0.771, 95% Cl = -4.0 to +8.0, LA -44.7 to +48.7. In conclusion, assumed oxygen consumption values, using our new formula, are in better agreement with the actual values than those found according to LaFarge and Miettinen's formulae.

Vascular capacitance and cardiac output in pacing-induced canine models of acute and chronic heart failure.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1995-11-01

The relationship between stressed and total blood volume, total vascular capacitance, central blood volume, cardiac output (CO), and pulmonary capillary wedge pressure (Ppcw) was investigated in pacing-induced acute and chronic heart failure. Acute heart failure was induced in anesthetized splenectomized dogs by a volume load (20 mL/kg over 10 min) during rapid right ventricular pacing at 250 beats/min (RRVP) for 60 min. Chronic heart failure was induced by continuous RRVP for 2-6 weeks (average 24 +/- 2 days). Total vascular compliance and capacitance were calculated from the mean circulatory filling pressure (Pmcf) during transient circulatory arrest after acetylcholine at three different circulating volumes. Stressed blood volume was calculated as a product of compliance and Pmcf, with the total blood volume measured by a dye dilution. Central blood volume (CBV) and CO were measured by thermodilution. Central (heart and lung) vascular capacitance was estimated from the plot of Ppcw against CBV. Acute volume loading without RRVP increased capacitance and CO, whereas after volume loading with RRVP, capacitance and CO were unaltered from baseline. Chronic RRVP reduced capacitance and CO. All interventions, volume +/- RRVP or chronic RRVP, increased stressed and central blood volumes and Ppcw. Acute or chronic RRVP reduced central vascular capacitance. Cardiac output was increased when stressed and unstressed blood volumes increased proportionately as during volume loading alone. When CO was reduced and Ppcw increased, as during chronic RRVP or acute RRVP plus a volume load, stressed blood volume was increased and unstressed blood volume was decreased. Thus, interventions that reduced CO and increased Ppcw also increased stressed and reduced unstressed blood volume and total vascular capacitance.

Usefulness of the Diagnosis "Decreased Cardiac Output (00029)" in Patients With Chronic Heart Failure.

PubMed

Rojas Sánchez, Lyda Zoraya; Hernández Vargas, Juliana Alexandra; Trujillo Cáceres, Silvia Juliana; Roa Díaz, Zayne Milena; Jurado Arenales, Adriana Milena; Toloza Pérez, Yesith Guillermo

2017-10-01

To determine the clinical and construct validity of the nursing diagnosis "decreased cardiac output" (DCO) in patients with chronic heart failure. Cross-sectional study. A total of 200 people were studied. The defining characteristics with the highest prevalence were as follows: arrhythmia (62.5%) and fatigue (61.5%). Adjustment measures such as infit and outfit were maintained between 0.50 and 1.56 and the total variance explained by the measures was 29.3%. This study determined the clinical validity of the nursing diagnosis DCO. Regarding construct validity, adjustment of the defining characteristics to the Rasch model was observed. This study improves the evidence-based practice of nursing and strengthened the role of the nurse who leads care to this population. Determinar la validez clínica y de constructo del diagnóstico de enfermería "Disminución del Gasto Cardíaco" en pacientes con falla cardíaca crónica. MÉTODOS: Estudio de corte transversal. Un total de 200 pacientes fueron estudiados. Las características definitorias con las mayores prevalencias fueron: arritmia (62.5%) y fatiga (61.5%). Medidas de ajuste como el infit y outfit se mantuvieron entre 0.50 y 1.56. El total de la varianza explicada por las medidas fue de 29.3%. Este estudio determinó la validez clínica del diagnóstico de enfermería "Disminución del Gasto Cardíaco". En cuanto a la validez de constructo, se observó que 19 de las 21 características definitorias se ajustaron al modelo Rasch. IMPLICACIONES PARA LA PRÁCTICA DE ENFERMERÍA: Este estudio mejora la práctica basada en la evidencia de enfermería y fortalece el rol de las enfermeras que lideran el cuidado en esta población. © 2016 NANDA International, Inc.

Role of cardiac output and the autonomic nervous system in the antinatriuretic response to acute constriction of the thoracic superior vena cava.

NASA Technical Reports Server (NTRS)

Schrier, R. W.; Humphreys, M. H.; Ufferman, R. C.

1971-01-01

Study of the differential characteristics of hepatic congestion and decreased cardiac output in terms of potential afferent stimuli in the antinatriuretic effect of acute thoracic inferior vena cava (TIVC) constriction. An attempt is made to see if the autonomic nervous system is involved in the antinatriuretic effect of acute TIVC or thoracic superior vena cava constriction.

Haemodynamic effects of vasoactive agents following chronic state of high cardiac output in anaesthetized rats.

PubMed

Guo, Liang; Tabrizchi, Reza

2008-05-31

The arteriovenous fistula model of circulation can produce a high output and low peripheral resistance situation. Here, we have examined the effects of noradrenaline, vasopressin and sodium nitroprusside on cardiac index, mean arterial blood pressure, venous tone, resistance to venous return, arterial resistance, and blood volume in chronically shunted anaesthetized rats. The cardiac index of rats with chronic arteriovenous fistula (AVF) was significantly higher (36.65+/-2.28 ml/min per 100 g; (mean+/-S.E.M.; n=24) in comparison to sham-operated rats (20.04+/-0.86 ml/min per 100 g; mean+/-S.E.M.; n=8). Cardiac index did not significantly change during the infusion of noradrenaline (1.0, 3.0 and 10 microg/kg per min), vasopressin (10, 30, 100 ng/kg per min) or sodium nitroprusside (0.1, 0.3 and 1.0 microg/kg per min) compared to saline infusion in AVF animals. Infusion of noradrenaline significantly increased heart rate, dP/dt, mean circulatory filling pressure (Pmcf) and resistance to venous return without affecting mean arterial blood pressure when compared to saline infusion. Administration of vasopressin significantly increased dP/dt, mean arterial blood pressure, and Pmcf without affecting heart rate, resistance to venous return or arterial resistance compared to saline infusion. Infusion of sodium nitroprusside did not significantly affect any haemodynamic parameter measured when compared to saline infusion. The results indicate that the presence of chronic AVF alters responsiveness of the various segments of the circulatory system to vasoactive agents. Moreover, it produces a major impediment to overall changes that can normally be induced following the infusion of such agents.

Monitoring of intrathoracic volemia and cardiac output in critically ill children.

PubMed

Cecchetti, C; Stoppa, F; Vanacore, N; Barbieri, M A; Raucci, U; Pasotti, E; Tomasello, C; Marano, M; Pirozzi, N

2003-12-01

Hemodynamic monitoring is an important step in the management of critically ill children despite the difficulty in measuring preload indices continuously. The aim of the study was to analyze cardiac output parameters and preload indices after acute changes in mean airway pressure and volemia. Twenty-three children treated at our unit were enrolled in a prospective non randomized cohort study. Respiration was supported by controlled mechanical ventilation with positive expiratory-end pressure (PEEP), peak inspiratory pressure <20 cm H(2)O and mean airway pressure <10 cm H(2)O, and hemodynamic monitoring using the PiCCO system. Hemodynamic parameters were measured at T0 (base line), T(1) (after an increase in PEEP of 5 cm H(2)O for 10 min), and T(2) (after fluid challenge). The statistical analysis (BMPD New System software package) comprised comparison of changes at T(0) vs T(1), T(1) vs T(2) and T(0) vs T(2), construction of 3 correlation matrices and multiple linear regression analysis. Sixty-nine hemodynamic parameters were measured in the 23 patients. A comparison between T(0) and T(1) showed no significant changes; differences between T(0) and T(2) were found for cardiac index (CI), (p=0.003); between T(0) and T(2) significant differences were found for CI (p=0.0015), intrathoracic blood volume index (ITBVI) (p=0.04) and stroke volume index (SVI) (p=0.06). The analysis of the correlation matrices yielded ITBVI with CI (p=0.0006), ITBVI with SVI (p=1 x 10(-5)), CI with SVI (p=0.002); a significant correlation between CI and extravascular lung water index (EVLWI) was found only at T(1). Multiple linear regression analysis showed that ITBVI and SVI were predictive for variance of CI at each time point. ITBVI measured by a volumetric monitoring system such as the PiCCO may be considered a sensitive preload indicator also in critically ill children.

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

NASA Technical Reports Server (NTRS)

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

1993-01-01

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.

Prognostic value of cardiac power output to left ventricular mass in patients with left ventricular dysfunction and dobutamine stress echo negative by wall motion criteria.

PubMed

Cortigiani, Lauro; Sorbo, Simone; Miccoli, Mario; Scali, Maria Chiara; Simioniuc, Anca; Morrone, Doralisa; Bovenzi, Francesco; Marzilli, Mario; Dini, Frank Lloyd

2017-02-01

Cardiac power output to left ventricular mass (power/mass) is an index of myocardial efficiency reflecting the rate at which cardiac work is delivered with respect to the potential energy stored in the left ventricular mass. In the present study, we sought to investigate the capability of power/mass assessed at peak of dobutamine stress echocardiography to predict mortality in patients with ischaemic cardiomyopathy and no inducible ischaemia. One-hundred eleven patients (95 males; age 68 ± 10 years) with 35 ± 7% mean left ventricular ejection fraction and a dobutamine stress echocardiography (up to 40 µg/kg/min) negative by wall motion criteria formed the study population. Power/mass at peak stress was obtained as the product of a constant (K = 2.22 × 10 -1 ) with cardiac output and the mean arterial pressure divided by left ventricular mass to convert the units to W/100 g. Patients were followed up for a median of 29 months (inter-quartile range 16-72 months). All-cause mortality was the only accepted clinical end point. Mean peak-stress power/mass was 0.70 ± 0.31 W/100 g. During follow-up, 29 deaths (26%) were registered. With a receiver operating characteristic analysis, a peak-stress power/mass ≤0.50 W/100 g [area under curve 0.72 (95% CI 0.63; 0.80), sensitivity 59%, specificity 80%] was the best value for predicting mortality. Univariate prognostic indicators were age, male sex, peak-stress ejection fraction, peak-stress stroke volume, peak-stress cardiac output, peak-stress cardiac power output ≤1.48 W, and peak-stress power/mass ≤0.50 W/100 g. At multivariate analysis, age (HR 1.08, 95% CI 1.04; 1.14; P = 0.004) and peak-stress power/mass ≤0.50 W/100 g (HR 4.05, 95% CI 1.36; 12.00; P = 0.01) provided independent prognostic information. Three-year mortality was 14% in patients with peak-stress power/mass >0.50 W/100 g and 47% in those with peak-stress power/mass ≤0.50 W/100 g (log-rank 20.4; P < 0.0001). Power/mass assessed at peak of

The effects on increasing cardiac output with adrenaline or isoprenaline on arterial haemoglobin oxygen saturation and shunt during one-lung ventilation.

PubMed

Russell, W J; James, M F

2000-12-01

Theoretically, if the cardiac output were increased in the presence of a given intrapulmonary shunt, the arterial haemoglobin oxygen saturation (SaO2) should improve as the venous oxygen extraction per ml of blood decreases. To test this hypothesis, eight pigs were subjected to one-lung ventilation and adrenaline and isoprenaline infusions used to increase the cardiac output. The mixed venous oxygen, shunt fraction and oxygen consumption were measured. With both adrenaline and isoprenaline, although there was a small rise in mixed venous oxygen content, there was a fall in SaO2. With adrenaline, the mean shunt rose from 48% to 65%, the mean oxygen consumption rose from 126 ml/min to 134 ml/min and the mean SaO2 fell from 86.9% to 82.5%. With isoprenaline, the mean shunt rose from 45% to 59%, the mean oxygen consumption rose from 121 ml/min to 137 ml/min and the mean SaO2 fell from 89.5% to 84.7%. It is concluded that potential improvement in SaO2, which might occur from a catecholamine-induced increase in mixed venous oxygen content during one-lung ventilation, is more than offset by increased shunting and oxygen consumption which reduce SaO2.

Comparison of Levosimendan, Milrinone and Dobutamine in treating Low Cardiac Output Syndrome Following Valve Replacement Surgeries with Cardiopulmonary Bypass

PubMed Central

Sunny; Karim, Habib Md Reazaul; Saikia, Manuj Kumar; Bhattacharyya, Prithwis; Dey, Samarjit

2016-01-01

Introduction Low Cardiac Output Syndrome (LCOS) following Cardiopulmonary Bypass (CPB) is common and associated with increased mortality. Maintenance of adequate cardiac output is one of the primary objectives in management of such patients. Aim To compare Levosimendan, Milrinone and Dobutamine for the treatment of LCOS after CPB in patients who underwent valve replacement surgeries. Materials and Methods Sixty eligible patients meeting LCOS were allocated into three treatment groups: Group A-Levosimendan (loading dose 10μg/kg over 10 minutes, followed by 0.1μg/kg/min); Group B-Milrinone (loading dose 50 mcg/kg over 10 minutes followed by 0.5mcg/kg/min) and Group C-Dobutamine @ 5μg/kg/min to achieve target cardiac index (CI) of > 2.5 L/min/m2. In case of failure, other drugs were added as required. Hemodynamic parameters were monitored using EV1000TM clinical platform till 30 minutes post CPB. INSTAT software was used for statistics and p<0.05 was considered significant. Results The mean±standard deviation of time taken by Dobutamine, Levosimendan and Milrinone to bring the CI to target were 11.1±8.79, 11.3±6.34 and 16.62±9.33 minutes respectively (p=0.064). Levosimendan was equally effective in increasing and maintaining adequate CI as compared to Dobutamine (p>0.05). Levosimendan and Milrinone increased MAP (Mean Arterial Pressure) equally while Dobutamine was more effective as compared to both Levosimendan and Milrinone 20th minute onwards (p<0.01). Milrinone was less effective in increasing the stroke volume as compared to Dobutamine and Levosimendan while Dobutamine and Levosimendan were equally effective. There was no difference in the HR (Heart Rate) achieved with all these three drugs. Conclusion Levosimendan is equally effective to Dobutamine and better than Milrinone for the treatment of LCOS following CPB in patients undergoing valve replacement surgeries. PMID:28208977

Evidence of cardiac functional reserve upon exhaustion during incremental exercise to determine VO2max.

PubMed

Elliott, Adrian D; Skowno, Justin; Prabhu, Mahesh; Noakes, Timothy David; Ansley, Les

2015-01-01

There remains considerable debate regarding the limiting factor(s) for maximal oxygen uptake (VO2max). Previous studies have shown that the central circulation may be the primary limiting factor for VO2max and that cardiac work increases beyond VO2max. We sought to evaluate whether the work of the heart limits VO2max during upright incremental cycle exercise to exhaustion. Eight trained men completed two incremental exercise trials, each terminating with exercise at two different rates of work eliciting VO2max (MAX and SUPRAMAX). During each exercise trial we continuously recorded cardiac output using pulse-contour analysis calibrated with a lithium dilution method. Intra-arterial pressure was recorded from the radial artery while pulmonary gas exchange was measured continuously for an assessment of oxygen uptake. The workload during SUPRAMAX (mean±SD: 346.5±43.2 W) was 10% greater than that achieved during MAX (315±39.3 W). There was no significant difference between MAX and SUPRAMAX for Q (28.7 vs 29.4 L/min) or VO2 (4.3 vs 4.3 L/min). Mean arterial pressure was significantly higher during SUPRAMAX, corresponding to a higher cardiac power output (8.1 vs 8.5 W; p<0.06). Despite similar VO2 and Q, the greater cardiac work during SUPRAMAX supports the view that the heart is working submaximally at exhaustion during an incremental exercise test (MAX). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Effect of a perioperative, cardiac output-guided hemodynamic therapy algorithm on outcomes following major gastrointestinal surgery: a randomized clinical trial and systematic review.

PubMed

Pearse, Rupert M; Harrison, David A; MacDonald, Neil; Gillies, Michael A; Blunt, Mark; Ackland, Gareth; Grocott, Michael P W; Ahern, Aoife; Griggs, Kathryn; Scott, Rachael; Hinds, Charles; Rowan, Kathryn

2014-06-04

Small trials suggest that postoperative outcomes may be improved by the use of cardiac output monitoring to guide administration of intravenous fluid and inotropic drugs as part of a hemodynamic therapy algorithm. To evaluate the clinical effectiveness of a perioperative, cardiac output-guided hemodynamic therapy algorithm. OPTIMISE was a pragmatic, multicenter, randomized, observer-blinded trial of 734 high-risk patients aged 50 years or older undergoing major gastrointestinal surgery at 17 acute care hospitals in the United Kingdom. An updated systematic review and meta-analysis were also conducted including randomized trials published from 1966 to February 2014. Patients were randomly assigned to a cardiac output-guided hemodynamic therapy algorithm for intravenous fluid and inotrope (dopexamine) infusion during and 6 hours following surgery (n=368) or to usual care (n=366). The primary outcome was a composite of predefined 30-day moderate or major complications and mortality. Secondary outcomes were morbidity on day 7; infection, critical care-free days, and all-cause mortality at 30 days; all-cause mortality at 180 days; and length of hospital stay. Baseline patient characteristics, clinical care, and volumes of intravenous fluid were similar between groups. Care was nonadherent to the allocated treatment for less than 10% of patients in each group. The primary outcome occurred in 36.6% of intervention and 43.4% of usual care participants (relative risk [RR], 0.84 [95% CI, 0.71-1.01]; absolute risk reduction, 6.8% [95% CI, -0.3% to 13.9%]; P = .07). There was no significant difference between groups for any secondary outcomes. Five intervention patients (1.4%) experienced cardiovascular serious adverse events within 24 hours compared with none in the usual care group. Findings of the meta-analysis of 38 trials, including data from this study, suggest that the intervention is associated with fewer complications (intervention, 488/1548 [31.5%] vs control

β-Adrenergic or parasympathetic inhibition, heart rate and cardiac output during normoxic and acute hypoxic exercise in humans

PubMed Central

Hopkins, Susan R; Bogaard, Harm J; Niizeki, Kyuichi; Yamaya, Yoshiki; Ziegler, Michael G; Wagner, Peter D

2003-01-01

Acute hypoxia increases heart rate (HR) and cardiac output () at a given oxygen consumption () during submaximal exercise. It is widely believed that the underlying mechanism involves increased sympathetic activation and circulating catecholamines acting on cardiac β receptors. Recent evidence indicating a continued role for parasympathetic modulation of HR during moderate exercise suggests that increased parasympathetic withdrawal plays a part in the increase in HR and during hypoxic exercise. To test this, we separately blocked the β-sympathetic and parasympathetic arms of the autonomic nervous system (ANS) in six healthy subjects (five male, one female; mean ± s.e.m. age = 31.7 ± 1.6 years, normoxic maximal () = 3.1 ± 0.3 l min−1) during exercise in conditions of normoxia and acute hypoxia (inspired oxygen fraction = 0.125) to . Data were collected on different days under the following conditions: (1)control, (2) after 8.0 mg propranolol I.V. and (3) after 0.8 mg glycopyrrolate I.V. was measured using open-circuit acetylene uptake. Hypoxia increased venous [adrenaline] and [noradrenaline] but not [dopamine] at a given (P < 0.05, P < 0.01 and P = 0.2, respectively). HR/ and / increased during hypoxia in all three conditions (P < 0.05). Unexpectedly, the effects of hypoxia on HR and were not significantly different from control with either β-sympathetic or parasympathetic inhibition. These data suggest that although acute exposure to hypoxia increases circulating [catecholamines], the effects of hypoxia on HR and do not necessarily require intact cardiac muscarinic and β receptors. It may be that cardiac α receptors play a primary role in elevating HR and during hypoxic exercise, or perhaps offer an alternative mechanism when other ANS pathways are blocked. PMID:12766243

Estimation of cardiac output and pulmonary vascular resistance by contrast echocardiography transit time measurement: a prospective pilot study.

PubMed

Choi, Brian G; Sanai, Reza; Yang, Benjamin; Young, Heather A; Mazhari, Ramesh; Reiner, Jonathan S; Lewis, Jannet F

2014-10-31

Studies with other imaging modalities have demonstrated a relationship between contrast transit and cardiac output (CO) and pulmonary vascular resistance (PVR). We tested the hypothesis that the transit time during contrast echocardiography could accurately estimate both CO and PVR compared to right heart catheterization (RHC). 27 patients scheduled for RHC had 2D-echocardiogram immediately prior to RHC. 3 ml of DEFINITY contrast followed by a 10 ml saline flush was injected, and a multi-cycle echo clip was acquired from the beginning of injection to opacification of the left ventricle. 2D-echo based calculations of CO and PVR along with the DEFINITY-based transit time calculations were subsequently correlated with the RHC-determined CO and PVR. The transit time from full opacification of the right ventricle to full opacification of the left ventricle inversely correlated with CO (r=-0.61, p<0.001). The transit time from peak opacification of the right ventricle to first appearance in the left ventricle moderately correlated with PVR (r=0.46, p<0.01). Previously described echocardiographic methods for the determination of CO (Huntsman method) and PVR (Abbas and Haddad methods) did not correlate with RHC-determined values (p = 0.20 for CO, p = 0.18 and p = 0.22 for PVR, respectively). The contrast transit time method demonstrated reliable intra- (p<0.0001) and inter-observer correlation (p<0.001). We describe a novel method for the quantification of CO and estimation of PVR using contrast echocardiography transit time. This technique adds to the methodologies used for noninvasive hemodynamic assessment, but requires further validation to determine overall applicability.

[Clinical practice guide for the management of low cardiac output syndrome in the postoperative period of heart surgery].

PubMed

Pérez Vela, J L; Martín Benítez, J C; Carrasco González, M; de la Cal López, M A; Hinojosa Pérez, R; Sagredo Meneses, V; del Nogal Saez, F

2012-05-01

The low cardiac output syndrome is a potential complication in cardiac surgery patients and associated with increased morbidity and mortality. This guide is to provide recommendations for the management of these patients, immediately after surgery, admitted to the ICU. The recommendations are grouped into different sections, trying to answer from the most basic concepts such as the definition to the different sections of basic and advanced monitoring and ending with the complex management of this syndrome. We propose an algorithm for initial management, as well as two other for ventricular failure (predominantly left or right). Most of the recommendations are based on expert consensus because of the lack of randomized trials of adequate design and sample size in this group of patients. The quality of evidence and strength of the recommendations were made following the GRADE methodology. The guide is presented as a list of recommendations (and level of evidence for each recommendation) for each question on the selected topic. Then for each question, we proceed to the justification of the recommendations. Copyright © 2011 Elsevier España, S.L. y SEMICYUC. All rights reserved.

Methodological concerns for determining power output in the jump squat.

PubMed

Cormie, Prue; Deane, Russell; McBride, Jeffrey M

2007-05-01

The purpose of this study was to investigate the validity of power measurement techniques during the jump squat (JS) utilizing various combinations of a force plate and linear position transducer (LPT) devices. Nine men with at least 6 months of prior resistance training experience participated in this acute investigation. One repetition maximums (1RM) in the squat were determined, followed by JS testing under 2 loading conditions (30% of 1RM [JS30] and 90% of 1RM [JS90]). Three different techniques were used simultaneously in data collection: (a) 1 linear position transducer (1-LPT); (b) 1 linear position transducer and a force plate (1-LPT + FP); and (c) 2 linear position transducers and a force place (2-LPT + FP). Vertical velocity-, force-, and power-time curves were calculated for each lift using these methodologies and were compared. Peak force and peak power were overestimated by 1-LPT in both JS30 and JS90 compared with 2-LPT + FP and 1-LPT + FP (p determined by 2-LPT + FP was significantly higher than that determined by 1-LPT + FP under the JS90 loading condition. Peak vertical velocity determined by 2-LPT + FP was significantly lower than that determined by either 1-LPT and 1-LPT + FP in JS90. This investigation indicates that peak power and the timing of power output in the jump squat varies according to the measurement technique utilized. The 1-LPT methodology is not a valid means of determining power output in the jump squat. Furthermore, the 1-LPT + FP method may not accurately represent power output in free weight movements that involve a significant amount of horizontal motion.

Right atrial pressure: determinant or result of change in venous return?

PubMed

Bendjelid, Karim

2005-11-01

According to the concept of Guyton, cardiac output is largely controlled by venous return, which is determined by the difference between mean systemic venous pressure and right atrial pressure. In the analysis of the venous return curve, other authors have suggested that right atrial pressure is the dependent variable and venous return is the independent variable (right atrial pressure decreased because cardiac output increased). The present report analyzes this historical debate, which has already lasted > 50 years.

Fluid balance, glomerular filtration rate, and urine output in dogs anesthetized for an orthopedic surgical procedure.

PubMed

Boscan, Pedro; Pypendop, Bruno H; Siao, Kristine T; Francey, Thierry; Dowers, Kristy; Cowgill, Larry; Ilkiw, Jan E

2010-05-01

To determine fluid retention, glomerular filtration rate, and urine output in dogs anesthetized for a surgical orthopedic procedure. 23 dogs treated with a tibial plateau leveling osteotomy. 12 dogs were used as a control group. Cardiac output was measured in 5 dogs, and 6 dogs received carprofen for at least 14 days. Dogs received oxymorphone, atropine, propofol, and isoflurane for anesthesia (duration, 4 hours). Urine and blood samples were obtained for analysis every 30 minutes. Lactated Ringer's solution was administered at 10 mL/kg/h. Urine output was measured and glomerular filtration rate was estimated. Fluid retention was measured by use of body weight, fluid balance, and bioimpedance spectroscopy. No difference was found among control, cardiac output, or carprofen groups, so data were combined. Median urine output and glomerular filtration rate were 0.46 mL/kg/h and 1.84 mL/kg/min. Dogs retained a large amount of fluids during anesthesia, as indicated by increased body weight, positive fluid balance, increased total body water volume, and increased extracellular fluid volume. The PCV, total protein concentration, and esophageal temperature decreased in a linear manner. Dogs anesthetized for a tibial plateau leveling osteotomy retained a large amount of fluids, had low urinary output, and had decreased PCV, total protein concentration, and esophageal temperature. Evaluation of urine output alone in anesthetized dogs may not be an adequate indicator of fluid balance.

Assessment of hemodynamic load components affecting optimization of cardiac resynchronization therapy by lumped parameter mode.

PubMed

Xu, Ke; Butlin, Mark; Avolio, Alberto P

2012-01-01

Timing of biventricular pacing devices employed in cardiac resynchronization therapy (CRT) is a critical determinant of efficacy of the procedure. Optimization is done by maximizing function in terms of arterial pressure (BP) or cardiac output (CO). However, BP and CO are also determined by the hemodynamic load of the pulmonary and systemic vasculature. This study aims to use a lumped parameter circulatory model to assess the influence of the arterial load on the atrio-ventricular (AV) and inter-ventricular (VV) delay for optimal CRT performance.

Design of a specialized computer for on-line monitoring of cardiac stroke volume

NASA Technical Reports Server (NTRS)

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

1972-01-01

The design of a specialized analog computer for on-line determination of cardiac stroke volume by means of a modified version of the pressure pulse contour method is presented. The design consists of an analog circuit for computation and a timing circuit for detecting necessary events on the pressure waveform. Readouts of arterial pressures, systolic duration, heart rate, percent change in stroke volume, and percent change in cardiac output are provided for monitoring cardiac patients. Laboratory results showed that computational accuracy was within 3 percent, while animal experiments verified the operational capability of the computer. Patient safety considerations are also discussed.

A randomized controlled trial of levosimendan to reduce mortality in high-risk cardiac surgery patients (CHEETAH): Rationale and design.

PubMed

Zangrillo, Alberto; Alvaro, Gabriele; Pisano, Antonio; Guarracino, Fabio; Lobreglio, Rosetta; Bradic, Nikola; Lembo, Rosalba; Gianni, Stefano; Calabrò, Maria Grazia; Likhvantsev, Valery; Grigoryev, Evgeny; Buscaglia, Giuseppe; Pala, Giovanni; Auci, Elisabetta; Amantea, Bruno; Monaco, Fabrizio; De Vuono, Giovanni; Corcione, Antonio; Galdieri, Nicola; Cariello, Claudia; Bove, Tiziana; Fominskiy, Evgeny; Auriemma, Stefano; Baiocchi, Massimo; Bianchi, Alessandro; Frontini, Mario; Paternoster, Gianluca; Sangalli, Fabio; Wang, Chew-Yin; Zucchetti, Maria Chiara; Biondi-Zoccai, Giuseppe; Gemma, Marco; Lipinski, Michael J; Lomivorotov, Vladimir V; Landoni, Giovanni

2016-07-01

Patients undergoing cardiac surgery are at risk of perioperative low cardiac output syndrome due to postoperative myocardial dysfunction. Myocardial dysfunction in patients undergoing cardiac surgery is a potential indication for the use of levosimendan, a calcium sensitizer with 3 beneficial cardiovascular effects (inotropic, vasodilatory, and anti-inflammatory), which appears effective in improving clinically relevant outcomes. Double-blind, placebo-controlled, multicenter randomized trial. Tertiary care hospitals. Cardiac surgery patients (n = 1,000) with postoperative myocardial dysfunction (defined as patients with intraaortic balloon pump and/or high-dose standard inotropic support) will be randomized to receive a continuous infusion of either levosimendan (0.05-0.2 μg/[kg min]) or placebo for 24-48 hours. The primary end point will be 30-day mortality. Secondary end points will be mortality at 1 year, time on mechanical ventilation, acute kidney injury, decision to stop the study drug due to adverse events or to start open-label levosimendan, and length of intensive care unit and hospital stay. We will test the hypothesis that levosimendan reduces 30-day mortality in cardiac surgery patients with postoperative myocardial dysfunction. This trial is planned to determine whether levosimendan could improve survival in patients with postoperative low cardiac output syndrome. The results of this double-blind, placebo-controlled randomized trial may provide important insights into the management of low cardiac output in cardiac surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

[Cardiac failure in endocrine diseases].

PubMed

Hashizume, K

1993-05-01

Several endocrine diseases show the symptoms of cardiac failure. Among them, patients with acromegaly show a specific cardiomyopathy which results in a severe left-sided cardiac failure. Hypoparathyroidism also induces cardiac failure, which is resulted from hypocalcemia and low levels of serum parathyroid hormone. In the cases of hypothyroidism, the patients with myxedemal coma show a severe cardiac failure, which is characterized by disturbance of central nervous system, renal function, and cardiac function. In the patients with thyroid crisis (storm), the cardiac failure comes from the great reduction of cardiac output with dehydration. The reduction of circulation volume, observed in the patients with pheochromocytoma easily induces cardiac failure (shock) just after the removal of adrenal tumor. In patients with malignant carcinoid syndrome, right-sided ventricular failure which may be occurred through the actions of biogenic amines is observed.

Determinants of the relationship between cost and survival time after elective adult cardiac surgery.

PubMed

Ho, K M

2014-05-01

Cardiac surgery is increasingly performed on elderly patients with multiple comorbid conditions, but the determinants of the relationship between cost and survival time after cardiac surgery for patients with a serious cardiac condition remain uncertain. Using the long-term outcome data of a cohort study on adult cardiac surgical patients, the relationship between cost and survival time after cardiac surgery from a hospital service perspective was determined. The total cost for each patient was estimated by the costs of the surgical procedures, intra-aortic balloon pump utilisation, operating theatre utilisation, blood products, intensive care unit stay and cumulative hospital stay up to a median follow-up time of 30 months. Of the 2131 patients considered in this study, a total cost >A$100,000 per life-year after cardiac surgery was observed only in 171 patients (8.0%, 95% confidence interval 6.9 to 9.3%). Age, Charlson Comorbidity Index and EuroSCORE were all related to the cost per life-year after cardiac surgery, but EuroSCORE (odds ratio 1.26 per score increment, 95% confidence interval 1.18 to 1.35, P=0.001) was, by far, the most important determinant and explained 32% of the variability in cost per life-year after cardiac surgery. Patients with a high EuroSCORE were associated with a substantially longer length of intensive care unit stay and cumulative hospital stay, as well as a shorter survival time after cardiac surgery compared to patients with a lower EuroSCORE. Of all the subgroups of patients examined, only patients with a EuroSCORE >5 were consistently associated with a cost >A$100,000 per life-year (cost per life-year $183,148, 95% confidence interval 125, 394 to 240, 902).

Relationship between cardiac function and resting cerebral blood flow: MRI measurements in healthy elderly subjects.

PubMed

Henriksen, Otto M; Jensen, Lars T; Krabbe, Katja; Larsson, Henrik B W; Rostrup, Egill

2014-11-01

Although both impaired cardiac function and reduced cerebral blood flow are associated with ageing, current knowledge of the influence of cardiac function on resting cerebral blood flow (CBF) is limited. The aim of this study was to investigate the potential effects of cardiac function on CBF. CBF and cardiac output were measured in 31 healthy subjects 50-75 years old using magnetic resonance imaging techniques. Mean values of CBF, cardiac output and cardiac index were 43.6 ml per 100 g min(-1), 5.5 l min(-1) and 2.7 l min(-1) m(-2), respectively, in males, and 53.4 ml per 100 g min(-1), 4.3 l min(-1) and 2.4 l min(-1) m(-2), respectively, in females. No effects of cardiac output or cardiac index on CBF or structural signs of brain ageing were observed. However, fractional brain flow defined as the ratio of total brain flow to cardiac output was inversely correlated with cardiac index (r(2) = 0.22, P = 0.008) and furthermore lower in males than in females (8.6% versus 12.5%, P = 0.003). Fractional brain flow was also inversely correlated with cerebral white matter lesion grade, although this effect was not significant when adjusted for age. Frequency analysis of heart rate variability showed a gender-related inverse association of increased low-to-high-frequency power ratio with CBF and fractional brain flow. The findings do not support a direct effect of cardiac function on CBF, but demonstrates gender-related differences in cardiac output distribution. We propose fractional brain flow as a novel index that may be a useful marker of adequate brain perfusion in the context of ageing as well as cardiovascular disease. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Conversion of cardiac performance data in analog form for digital computer entry

NASA Technical Reports Server (NTRS)

Miller, R. L.

1972-01-01

A system is presented which will reduce analog cardiac performance data and convert the results to digital form for direct entry into a commercial time-shared computer. Circuits are discussed which perform the measurement and digital conversion of instantaneous systolic and diastolic parameters from the analog blood pressure waveform. Digital averaging over a selected number of heart cycles is performed on these measurements, as well as those of flow and heart rate. The determination of average cardiac output and peripheral resistance, including trends, is the end result after processing by digital computer.

Accuracy of Cardiac Output by Nine Different Pulse Contour Algorithms in Cardiac Surgery Patients: A Comparison with Transpulmonary Thermodilution.

PubMed

Broch, Ole; Bein, Berthold; Gruenewald, Matthias; Masing, Sarah; Huenges, Katharina; Haneya, Assad; Steinfath, Markus; Renner, Jochen

2016-01-01

Objective. Today, there exist several different pulse contour algorithms for calculation of cardiac output (CO). The aim of the present study was to compare the accuracy of nine different pulse contour algorithms with transpulmonary thermodilution before and after cardiopulmonary bypass (CPB). Methods. Thirty patients scheduled for elective coronary surgery were studied before and after CPB. A passive leg raising maneuver was also performed. Measurements included CO obtained by transpulmonary thermodilution (CO TPTD ) and by nine pulse contour algorithms (CO X1-9 ). Calibration of pulse contour algorithms was performed by esophageal Doppler ultrasound after induction of anesthesia and 15 min after CPB. Correlations, Bland-Altman analysis, four-quadrant, and polar analysis were also calculated. Results. There was only a poor correlation between CO TPTD and CO X1-9 during passive leg raising and in the period before and after CPB. Percentage error exceeded the required 30% limit. Four-quadrant and polar analysis revealed poor trending ability for most algorithms before and after CPB. The Liljestrand-Zander algorithm revealed the best reliability. Conclusions. Estimation of CO by nine different pulse contour algorithms revealed poor accuracy compared with transpulmonary thermodilution. Furthermore, the less-invasive algorithms showed an insufficient capability for trending hemodynamic changes before and after CPB. The Liljestrand-Zander algorithm demonstrated the highest reliability. This trial is registered with NCT02438228 (ClinicalTrials.gov).

High-Intensity Interval Training Increases Cardiac Output and V˙O2max.

PubMed

Astorino, Todd A; Edmunds, Ross M; Clark, Amy; King, Leesa; Gallant, Rachael A; Namm, Samantha; Fischer, Anthony; Wood, Kimi M

2017-02-01

Increases in maximal oxygen uptake (V˙O2max) frequently occur with high-intensity interval training (HIIT), yet the specific adaptation explaining this result remains elusive. This study examined changes in V˙O2max and cardiac output (CO) in response to periodized HIIT. Thirty-nine active men and women (mean age and V˙O2max = 22.9 ± 5.4 yr and 39.6 ± 5.6 mL·kg·min) performed HIIT and 32 men and women (age and V˙O2max = 25.7 ± 4.5 yr and 40.7 ± 5.2 mL·kg·min) were nonexercising controls (CON). The first 10 sessions of HIIT required eight to ten 60 s bouts of cycling at 90%-110% percent peak power output interspersed with 75 s recovery, followed by randomization to one of three regimes (sprint interval training (SIT), high-volume interval training (HIITHI), or periodized interval training (PER) for the subsequent 10 sessions. Before, midway, and at the end of training, progressive cycling to exhaustion was completed during which V˙O2max and maximal CO were estimated. Compared with CON, significant (P < 0.001) increases in V˙O2max in HIIT + SIT (39.8 ± 7.3 mL·kg·min to 43.6 ± 6.1 mL·kg·min), HIIT + HIITHI (41.1 ± 4.9 mL·kg·min to 44.6 ± 7.0 mL·kg·min), and HIIT + PER (39.5 ± 5.6 mL·kg·min to 44.1 ± 5.4 mL·kg·min) occurred which were mediated by significant increases in maximal CO (20.0 ± 3.1 L·min to 21.7 ± 3.2 L·min, P = 0.04). Maximal stroke volume was increased with HIIT (P = 0.04), although there was no change in maximal HR (P = 0.88) or arteriovenous O2 difference (P = 0.36). These CO data are accurate and represent the mean changes from pre- to post-HIIT across all three training groups. Increases in V˙O2max exhibited in response to different HIIT regimes are due to improvements in oxygen delivery.

Effects of cardiac output on the onset of rocuronium-induced neuromuscular block in elderly patients.

PubMed

Shiraishi, Naoki; Aono, Mayu; Kameyama, Yasuhito; Yamamoto, Mai; Kitajima, Osamu; Suzuki, Takahiro

2018-05-21

The aim of this study was to elucidate the relationship between the onset of rocuronium-induced neuromuscular block and arterial pressure-based cardiac output (CO) in elderly patients. Forty elderly patients aged 65-83 years were enrolled in this study. After induction of anesthesia, contractions of the adductor pollicis muscle to ulnar nerve train-of-four stimulation were acceleromyographically evaluated and 1 mg/kg rocuronium was administered following CO measurement. The correlation between onset of rocuronium action and CO was analyzed. The mean [SD] CO reduced after induction of anesthesia from 5.1 [1.8] L/min to 3.8 [1.1] L/min. The onset time of rocuronium-induced neuromuscular block was 110.3 [23.9] s (range 60-165). There was a statistically significant inverse correlation between the onset time of rocuronium and CO [onset time (s) = - 13.2·CO + 159.7, R 2  = 0.376]. In the elderly, CO influences the onset of action of rocuronium.

A computational model-based validation of Guyton's analysis of cardiac output and venous return curves

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Cohen, R. J.; Mark, R. G.

2002-01-01

Guyton developed a popular approach for understanding the factors responsible for cardiac output (CO) regulation in which 1) the heart-lung unit and systemic circulation are independently characterized via CO and venous return (VR) curves, and 2) average CO and right atrial pressure (RAP) of the intact circulation are predicted by graphically intersecting the curves. However, this approach is virtually impossible to verify experimentally. We theoretically evaluated the approach with respect to a nonlinear, computational model of the pulsatile heart and circulation. We developed two sets of open circulation models to generate CO and VR curves, differing by the manner in which average RAP was varied. One set applied constant RAPs, while the other set applied pulsatile RAPs. Accurate prediction of intact, average CO and RAP was achieved only by intersecting the CO and VR curves generated with pulsatile RAPs because of the pulsatility and nonlinearity (e.g., systemic venous collapse) of the intact model. The CO and VR curves generated with pulsatile RAPs were also practically independent. This theoretical study therefore supports the validity of Guyton's graphical analysis.

Identification of prognostic markers in transthyretin and AL cardiac amyloidosis.

PubMed

Damy, Thibaud; Jaccard, Arnaud; Guellich, Aziz; Lavergne, David; Galat, Arnault; Deux, Jean-François; Hittinger, Luc; Dupuis, Jehan; Frenkel, Valérie; Rigaud, Charlotte; Plante-Bordeneuve, Violaine; Bodez, Diane; Mohty, Dania

2016-09-01

The prognosis of amyloidosis is known to depend heavily on cardiac function and may be improved by identifying patients at highest risk for adverse cardiac events. Identify predictors of mortality in patients with cardiac light-chain amyloidosis (AL), hereditary transthyretin amyloidosis (m-TTR), or wild-type transthyretin amyloidosis (WT-TTR) to prompt physician to refer these patients to dedicated centers. Observational study. About 266 patients referred for suspected cardiac amyloidosis (CA) in two French university centers were included. About 198 patients had CA (AL = 118, m-TTR = 57, and WT-TTR = 23). Their median (25th-75th percentile) age, NT-proBNP left ventricular ejection fraction were, respectively, 68 years (59-76), 2339 pg mL -1 (424-5974), and 60% (48-66). About 31% were in NYHA class III-IV. Interventricular septal thickness was greater in the m-TTR and WT-TTR groups than in the AL group (p < 0.0001). Median follow-up in survivor was 26 months (15-44) and 87 (44%) patients died. By multivariate analysis, independent predictors of mortality for AL amyloidosis were the following: age, cardiac output and NT-proBNP; for TTR amyloidosis was: NT-proBNP. When all amyloidosis were combined NT-proBNP, low cardiac output and pericardial effusion were independently associated with mortality. NT-proBNP is a strong prognosticator in the three types of cardiac amyloidosis. High NT-proBNP, low cardiac output, and pericardial effusion at the time of screening should prompt physician to refer the patients to amyloidosis referral center.

Pathologic Stimulus Determines Lineage Commitment of Cardiac C-kit+ Cells.

PubMed

Chen, Zhongming; Zhu, Wuqiang; Bender, Ingrid; Gong, Wuming; Kwak, Il-Youp; Yellamilli, Amritha; Hodges, Thomas J; Nemoto, Natsumi; Zhang, Jianyi; Garry, Daniel J; van Berlo, Jop H

2017-12-12

Although cardiac c-kit + cells are being tested in clinical trials, the circumstances that determine lineage differentiation of c-kit + cells in vivo are unknown. Recent findings suggest that endogenous cardiac c-kit + cells rarely contribute cardiomyocytes to the adult heart. We assessed whether various pathological stimuli differentially affect the eventual cell fates of c-kit + cells. We used single-cell sequencing and genetic lineage tracing of c-kit + cells to determine whether various pathological stimuli would result in different fates of c-kit + cells. Single-cell sequencing of cardiac CD45 - c-kit + cells showed innate heterogeneity, indicative of the existence of vascular and mesenchymal c-kit + cells in normal hearts. Cardiac pressure overload resulted in a modest increase in c-kit-derived cardiomyocytes, with significant increases in the numbers of endothelial cells and fibroblasts. Doxorubicin-induced acute cardiotoxicity did not increase c-kit-derived endothelial cell fates but instead induced cardiomyocyte differentiation. Mechanistically, doxorubicin-induced DNA damage in c-kit + cells resulted in expression of p53. Inhibition of p53 blocked cardiomyocyte differentiation in response to doxorubicin, whereas stabilization of p53 was sufficient to increase c-kit-derived cardiomyocyte differentiation. These results demonstrate that different pathological stimuli induce different cell fates of c-kit + cells in vivo. Although the overall rate of cardiomyocyte formation from c-kit + cells is still below clinically relevant levels, we show that p53 is central to the ability of c-kit + cells to adopt cardiomyocyte fates, which could lead to the development of strategies to preferentially generate cardiomyocytes from c-kit + cells. © 2017 American Heart Association, Inc.

Heart Performance Determination by Visualization in Larval Fishes: Influence of Alternative Models for Heart Shape and Volume

PubMed Central

Perrichon, Prescilla; Grosell, Martin; Burggren, Warren W.

2017-01-01

Understanding cardiac function in developing larval fishes is crucial for assessing their physiological condition and overall health. Cardiac output measurements in transparent fish larvae and other vertebrates have long been made by analyzing videos of the beating heart, and modeling this structure using a conventional simple prolate spheroid shape model. However, the larval fish heart changes shape during early development and subsequent maturation, but no consideration has been made of the effect of different heart geometries on cardiac output estimation. The present study assessed the validity of three different heart models (the “standard” prolate spheroid model as well as a cylinder and cone tip + cylinder model) applied to digital images of complete cardiac cycles in larval mahi-mahi and red drum. The inherent error of each model was determined to allow for more precise calculation of stroke volume and cardiac output. The conventional prolate spheroid and cone tip + cylinder models yielded significantly different stroke volume values at 56 hpf in red drum and from 56 to 104 hpf in mahi. End-diastolic and stroke volumes modeled by just a simple cylinder shape were 30–50% higher compared to the conventional prolate spheroid. However, when these values of stroke volume multiplied by heart rate to calculate cardiac output, no significant differences between models emerged because of considerable variability in heart rate. Essentially, the conventional prolate spheroid shape model provides the simplest measurement with lowest variability of stroke volume and cardiac output. However, assessment of heart function—especially if stroke volume is the focus of the study—should consider larval heart shape, with different models being applied on a species-by-species and developmental stage-by-stage basis for best estimation of cardiac output. PMID:28725199

Construct, concurrent and discriminant validity of Type D personality in the general population: associations with anxiety, depression, stress and cardiac output.

PubMed

Howard, Siobhán; Hughes, Brian M

2012-01-01

The Type D personality, identified by high negative affectivity paired with high social inhibition, has been associated with a number of health-related outcomes in (mainly) cardiac populations. However, despite its prevalence in the health-related literature, how this personality construct fits within existing personality theory has not been directly tested. Using a sample of 134 healthy university students, this study examined the Type D personality in terms of two well-established personality traits; introversion and neuroticism. Construct, concurrent and discriminant validity of this personality type was established through examination of the associations between the Type D personality and psychometrically assessed anxiety, depression and stress, as well as measurement of resting cardiovascular function. Results showed that while the Type D personality was easily represented using alternative measures of both introversion and neuroticism, associations with anxiety, depression and stress were mainly accounted for by neuroticism. Conversely, however, associations with resting cardiac output were attributable to the negative affectivity-social inhibition synergy, explicit within the Type D construct. Consequently, both the construct and concurrent validity of this personality type were confirmed, with discriminant validity evident on examination of physiological indices of well-being.

Assessment of interchangeability rate between 2 methods of measurements: An example with a cardiac output comparison study.

PubMed

Lorne, Emmanuel; Diouf, Momar; de Wilde, Robert B P; Fischer, Marc-Olivier

2018-02-01

The Bland-Altman (BA) and percentage error (PE) methods have been previously described to assess the agreement between 2 methods of medical or laboratory measurements. This type of approach raises several problems: the BA methodology constitutes a subjective approach to interchangeability, whereas the PE approach does not take into account the distribution of values over a range. We describe a new methodology that defines an interchangeability rate between 2 methods of measurement and cutoff values that determine the range of interchangeable values. We used a simulated data and a previously published data set to demonstrate the concept of the method. The interchangeability rate of 5 different cardiac output (CO) pulse contour techniques (Wesseling method, LiDCO, PiCCO, Hemac method, and Modelflow) was calculated, in comparison with the reference pulmonary artery thermodilution CO using our new method. In our example, Modelflow with a good interchangeability rate of 93% and a cutoff value of 4.8 L min, was found to be interchangeable with the thermodilution method for >95% of measurements. Modelflow had a higher interchangeability rate compared to Hemac (93% vs 86%; P = .022) or other monitors (Wesseling cZ = 76%, LiDCO = 73%, and PiCCO = 62%; P < .0001). Simulated data and reanalysis of a data set comparing 5 CO monitors against thermodilution CO showed that, depending on the repeatability of the reference method, the interchangeability rate combined with a cutoff value could be used to define the range of values over which interchangeability remains acceptable.

Effects of hypertrophic and dilated cardiomyopathy mutations on power output by human β-cardiac myosin.

PubMed

Spudich, James A; Aksel, Tural; Bartholomew, Sadie R; Nag, Suman; Kawana, Masataka; Yu, Elizabeth Choe; Sarkar, Saswata S; Sung, Jongmin; Sommese, Ruth F; Sutton, Shirley; Cho, Carol; Adhikari, Arjun S; Taylor, Rebecca; Liu, Chao; Trivedi, Darshan; Ruppel, Kathleen M

2016-01-01

Hypertrophic cardiomyopathy is the most frequently occurring inherited cardiovascular disease, with a prevalence of more than one in 500 individuals worldwide. Genetically acquired dilated cardiomyopathy is a related disease that is less prevalent. Both are caused by mutations in the genes encoding the fundamental force-generating protein machinery of the cardiac muscle sarcomere, including human β-cardiac myosin, the motor protein that powers ventricular contraction. Despite numerous studies, most performed with non-human or non-cardiac myosin, there is no clear consensus about the mechanism of action of these mutations on the function of human β-cardiac myosin. We are using a recombinantly expressed human β-cardiac myosin motor domain along with conventional and new methodologies to characterize the forces and velocities of the mutant myosins compared with wild type. Our studies are extending beyond myosin interactions with pure actin filaments to include the interaction of myosin with regulated actin filaments containing tropomyosin and troponin, the roles of regulatory light chain phosphorylation on the functions of the system, and the possible roles of myosin binding protein-C and titin, important regulatory components of both cardiac and skeletal muscles. © 2016. Published by The Company of Biologists Ltd.

Endurance Training and V˙O2max: Role of Maximal Cardiac Output and Oxygen Extraction.

PubMed

Montero, David; Diaz-Cañestro, Candela; Lundby, Carsten

2015-10-01

Although endurance training (ET) commonly augments maximal oxygen consumption (V˙O2max), it remains unclear whether such increase is associated with that of maximal cardiac output (Qmax) alone or along with arteriovenous oxygen difference (a-V˙O2diff). Herein, we sought to systematically review and determine the effects of ET on V˙O2max, Qmax, and a-V˙O2diff at maximal exercise, and on their associations, in healthy young subjects. We conducted a systematic search of MEDLINE, Scopus, and Web of Science (from their inception until September 2014) for articles assessing the effects of ET lasting ≥3 wk on V˙O2max and Qmax and/or a-V˙O2diff at maximal exercise in healthy young adults (mean age <40 yr). Meta-analyses were performed to determine standardized mean differences (SMD) in V˙O2max, Qmax, and a-V˙O2diff at maximal exercise between posttraining and pretraining measurements. Subgroup and meta-regression analyses were used to evaluate associations among SMD and potential moderating factors. Thirteen studies were included after systematic review, comprising a total of 130 untrained or moderately trained healthy young subjects (mean age, 22-28 yr). Duration of ET programs ranged from 5 to 12.9 wk. After data pooling, V˙O2max (SMD = 0.75, P < 0.0001) and Qmax (SMD = 0.64, P < 0.0001), but not a-V˙O2diff at maximal exercise (SMD = 0.21, P = 0.23), were increased after ET. No significant heterogeneity was detected. With meta-regression, the SMD in Qmax was positively associated with the SMD in V˙O2max (B = 0.91, P = 0.007). The SMD in a-V˙O2diff at maximal exercise was not associated with the SMD in V˙O2max (B = 0.20, P = 0.40). Based on a relatively small number of studies, improvement in V˙O2max following 5-13 wk of ET is associated with increase in Qmax, but not in a-V˙O2diff, in previously untrained to moderately trained healthy young individuals.

Relationship between plethysmographic waveform changes and hemodynamic variables in anesthetized, mechanically ventilated patients undergoing continuous cardiac output monitoring.

PubMed

Thiele, Robert H; Colquhoun, Douglas A; Patrie, James; Nie, Sarah H; Huffmyer, Julie L

2011-12-01

To assess the relation between photoplethysmographically-derived parameters and invasively-determined hemodynamic variables. After induction of anesthesia and placement of a Swan-Ganz CCOmbo catheter, a Nonin OEM III probe was placed on each patient's earlobe. Photoplethysmographic signals were recorded in conjunction with cardiac output. Photoplethysmographic metrics (amplitude of absorbance waveform, maximal slope of absorbance waveform, area under the curve, and width) were calculated offline and compared with invasively determined hemodynamic variables. Subject-specific associations between each dependent and independent variable pair were summarized on a per-subject basis by the nonparametric Spearman rank correlation coefficient. The bias-corrected accelerated bootstrap resampling procedure of Efron and Tibshirani was used to obtain a 95% confidence interval for the median subject-specific correlation coefficient, and Wilcoxon sign-rank tests were conducted to test the null hypothesis that the median of the subject-specific correlation coefficients were equal to 0. University hospital. Eighteen patients undergoing coronary artery bypass graft surgery. Placement of a Swan-Ganz CCOmbo catheter and a Nonin OEM III pulse oximetry probe. There was a positive, statistically significant correlation between stroke volume and width (median correlation coefficient, 0.29; confidence interval, 0.01-0.46; p = 0.034). The concordance between changes in stroke volume and changes in width was 53%. No other correlations achieved statistical significance. This study was unable to reproduce the results of prior studies. Only stroke volume and photoplethysmographic width were correlated in this study; however, the correlation and concordance (based on analysis of a 4-quadrant plot) were too weak to be clinically useful. Future studies in patients undergoing low-to-moderate risk surgery may result in improved correlations and clinical utility. Copyright © 2011 Elsevier Inc. All

Fluid challenge: tracking changes in cardiac output with blood pressure monitoring (invasive or non-invasive).

PubMed

Lakhal, Karim; Ehrmann, Stephan; Perrotin, Dominique; Wolff, Michel; Boulain, Thierry

2013-11-01

To assess whether invasive and non-invasive blood pressure (BP) monitoring allows the identification of patients who have responded to a fluid challenge, i.e., who have increased their cardiac output (CO). Patients with signs of circulatory failure were prospectively included. Before and after a fluid challenge, CO and the mean of four intra-arterial and oscillometric brachial cuff BP measurements were collected. Fluid responsiveness was defined by an increase in CO ≥10 or ≥15% in case of regular rhythm or arrhythmia, respectively. In 130 patients, the correlation between a fluid-induced increase in pulse pressure (Δ500mlPP) and fluid-induced increase in CO was weak and was similar for invasive and non-invasive measurements of BP: r² = 0.31 and r² = 0.29, respectively (both p < 0.001). For the identification of responders, invasive Δ500mlPP was associated with an area under the receiver-operating curve (AUC) of 0.82 (0.74-0.88), similar (p = 0.80) to that of non-invasive Δ500mlPP [AUC of 0.81 (0.73-0.87)]. Outside large gray zones of inconclusive values (5-23% for invasive Δ500mlPP and 4-35% for non-invasive Δ500mlPP, involving 35 and 48% of patients, respectively), the detection of responsiveness or unresponsiveness to fluid was reliable. Cardiac arrhythmia did not impair the performance of invasive or non-invasive Δ500mlPP. Other BP-derived indices did not outperform Δ500mlPP. As evidenced by large gray zones, BP-derived indices poorly reflected fluid responsiveness. However, in our deeply sedated population, a high increase in invasive pulse pressure (>23%) or even in non-invasive pulse pressure (>35%) reliably detected a response to fluid. In the absence of a marked increase in pulse pressure (<4-5%), a response to fluid was unlikely.

Cardiac changes induced by immersion and breath-hold diving in humans.

PubMed

Marabotti, Claudio; Scalzini, Alessandro; Cialoni, Danilo; Passera, Mirko; L'Abbate, Antonio; Bedini, Remo

2009-01-01

To evaluate the separate cardiovascular response to body immersion and increased environmental pressure during diving, 12 healthy male subjects (mean age 35.2 +/- 6.5 yr) underwent two-dimensional Doppler echocardiography in five different conditions: out of water (basal); head-out immersion while breathing (condition A); fully immersed at the surface while breathing (condition B) and breath holding (condition C); and breath-hold diving at 5-m depth (condition D). Heart rate, left ventricular volumes, stroke volume, and cardiac output were obtained by underwater echocardiography. Early (E) and late (A) transmitral flow velocities, their ratio (E/A), and deceleration time of E (DTE) were also obtained from pulsed-wave Doppler, as left ventricular diastolic function indexes. The experimental protocol induced significant reductions in left ventricular volumes, left ventricular stroke volume (P < 0.05), cardiac output (P < 0.001), and heart rate (P < 0.05). A significant increase in E peak (P < 0.01) and E/A (P < 0.01) and a significant reduction of DTE (P < 0.01) were also observed. Changes occurring during diving (condition D) accounted for most of the changes observed in the experimental series. In particular, cardiac output at condition D was significantly lower compared with each of the other experimental conditions, E/A was significantly higher during condition D than in conditions A and C. Finally, DTE was significantly shorter at condition D than in basal and condition C. This study confirms a reduction of cardiac output in diving humans. Since most of the changes were observed during diving, the increased environmental pressure seems responsible for this hemodynamic rearrangement. Left ventricular diastolic function changes suggest a constrictive effect on the heart, possibly accounting for cardiac output reduction.

Uncertainty and variability in computational and mathematical models of cardiac physiology.

PubMed

Mirams, Gary R; Pathmanathan, Pras; Gray, Richard A; Challenor, Peter; Clayton, Richard H

2016-12-01

Mathematical and computational models of cardiac physiology have been an integral component of cardiac electrophysiology since its inception, and are collectively known as the Cardiac Physiome. We identify and classify the numerous sources of variability and uncertainty in model formulation, parameters and other inputs that arise from both natural variation in experimental data and lack of knowledge. The impact of uncertainty on the outputs of Cardiac Physiome models is not well understood, and this limits their utility as clinical tools. We argue that incorporating variability and uncertainty should be a high priority for the future of the Cardiac Physiome. We suggest investigating the adoption of approaches developed in other areas of science and engineering while recognising unique challenges for the Cardiac Physiome; it is likely that novel methods will be necessary that require engagement with the mathematics and statistics community. The Cardiac Physiome effort is one of the most mature and successful applications of mathematical and computational modelling for describing and advancing the understanding of physiology. After five decades of development, physiological cardiac models are poised to realise the promise of translational research via clinical applications such as drug development and patient-specific approaches as well as ablation, cardiac resynchronisation and contractility modulation therapies. For models to be included as a vital component of the decision process in safety-critical applications, rigorous assessment of model credibility will be required. This White Paper describes one aspect of this process by identifying and classifying sources of variability and uncertainty in models as well as their implications for the application and development of cardiac models. We stress the need to understand and quantify the sources of variability and uncertainty in model inputs, and the impact of model structure and complexity and their consequences for

Potential for Personal Digital Assistant interference with implantable cardiac devices.

PubMed

Tri, Jeffrey L; Trusty, Jane M; Hayes, David L

2004-12-01

To determine whether the wireless local area network (WLAN) technology, specifically the Personal Digital Assistant (PDA), interferes with implantable cardiac pacemakers and defibrillators. Various pacemakers and defibrillators were tested in vitro at the Mayo Clinic in Rochester, Minn, between March 6 and July 30, 2003. These cardiac devices were exposed to an HP Compaq IPAQ PDA fitted with a Cisco Aironet WLAN card. Initial testing was designed to show whether the Aironet card radiated energy in a consistent pattern from the antenna of the PDA to ensure that subsequent cardiac device testing would not be affected by the orientation of the PDA to the cardiac device. Testing involved placing individual cardiac devices in a simulator and uniformly exposing each device at its most sensitive programmable value to the WLAN card set to maximum power. During testing with the Cisco WLAN Aironet card, all devices programmed to the unipolar or bipolar configuration single- or dual-chamber mode had normal pacing and sensing functions and exhibited no effects of electromagnetic interference except for 1 implantable cardioverter-defibrillator (ICD). This aberration was determined to relate to the design of the investigators' testing apparatus and not to the output of the PDA. The ICD device appropriately identified and labeled the electromagnetic aberration as "noise." We documented no electromagnetic interference caused by the WLAN technology by using in vitro testing of pacemakers and ICDs; however, testing ideally should be completed in vivo to confirm the lack of any clinically important interactions.

11C-4DST PET/CT Imaging of Cardiac Sarcoidosis: Comparison With 18F-FDG and Cardiac MRI.

PubMed

Hotta, Masatoshi; Minamimoto, Ryogo; Kubota, Shuji; Awaya, Toru; Hiroi, Yukio

2018-06-01

A 75-year-old woman with a history of sarcoidosis presenting with low cardiac output and complete right bundle-branch block underwent 4'-[methyl-C]-thiothymidine (4DST) PET/CT after cardiac MRI and FDG PET/CT for the evaluation of suspected cardiac sarcoidosis (CS) before treatment. Cardiac MRI revealed late gadolinium enhancement on the anterior-to-lateral and posterior wall, indicating CS. FDG uptake was shown on the anterior-to-lateral wall, but not on the posterior wall. In contrast, 4DST uptake was demonstrated on both anterior-to-lateral and posterior walls. Use of 4DST appears promising for detecting CS without dietary restriction, due to the lack of physiological uptake in myocardium.

Determination of the precision error of the pulmonary artery thermodilution catheter using an in vitro continuous flow test rig.

PubMed

Yang, Xiao-Xing; Critchley, Lester A; Joynt, Gavin M

2011-01-01

Thermodilution cardiac output using a pulmonary artery catheter is the reference method against which all new methods of cardiac output measurement are judged. However, thermodilution lacks precision and has a quoted precision error of ± 20%. There is uncertainty about its true precision and this causes difficulty when validating new cardiac output technology. Our aim in this investigation was to determine the current precision error of thermodilution measurements. A test rig through which water circulated at different constant rates with ports to insert catheters into a flow chamber was assembled. Flow rate was measured by an externally placed transonic flowprobe and meter. The meter was calibrated by timed filling of a cylinder. Arrow and Edwards 7Fr thermodilution catheters, connected to a Siemens SC9000 cardiac output monitor, were tested. Thermodilution readings were made by injecting 5 mL of ice-cold water. Precision error was divided into random and systematic components, which were determined separately. Between-readings (random) variability was determined for each catheter by taking sets of 10 readings at different flow rates. Coefficient of variation (CV) was calculated for each set and averaged. Between-catheter systems (systematic) variability was derived by plotting calibration lines for sets of catheters. Slopes were used to estimate the systematic component. Performances of 3 cardiac output monitors were compared: Siemens SC9000, Siemens Sirecust 1261, and Philips MP50. Five Arrow and 5 Edwards catheters were tested using the Siemens SC9000 monitor. Flow rates between 0.7 and 7.0 L/min were studied. The CV (random error) for Arrow was 5.4% and for Edwards was 4.8%. The random precision error was ± 10.0% (95% confidence limits). CV (systematic error) was 5.8% and 6.0%, respectively. The systematic precision error was ± 11.6%. The total precision error of a single thermodilution reading was ± 15.3% and ± 13.0% for triplicate readings. Precision

Effects of obstructive sleep apnea on hemodynamic parameters in patients entering cardiac rehabilitation.

PubMed

Hargens, Trent A; Aron, Adrian; Newsome, Laura J; Austin, Joseph L; Shafer, Brooke M

2015-01-01

Obstructive sleep apnea (OSA) is a prevalent form of sleep-disordered breathing. Evidence suggests that OSA may lead to cardiac remodeling, although the literature is equivocal. Previous literature suggests a high percentage of individuals entering a cardiac rehabilitation (CR) program also have OSA. The objective of this study was to determine whether resting hemodynamic variables were altered in OSA subjects entering CR compared with those without OSA, as determined by impedance cardiography. Subjects entering an early outpatient CR program were screened for OSA using an at-home screening device and verified by a sleep physician. Subjects were divided into an OSA group (n = 48) or a control group (n = 25) on the basis of the screening results. Hemodynamic variables were measured during supine rest using impedance cardiography. A 6-minute walk test was performed to assess functional capacity. The proportion of cardiac diagnoses was similar between groups. Overall, 66% of the subjects were positive for OSA. Subject groups did not differ by age, body mass index, heart rate, diastolic blood pressure, or functional capacity. Cardiac output, cardiac index, stroke volume, contractility index, and left cardiac work index were all significantly decreased in the OSA group compared with the control group (P < .05). Findings suggest that OSA results in decreased cardiac function in patients entering CR, likely because of pressure and volume changes associated with apneic events. This may place those individuals at a disadvantage in recovering from their cardiac event, and place them at increased risk for secondary complications.

Arterial pressure-based cardiac output monitoring: a multicenter validation of the third-generation software in septic patients.

PubMed

De Backer, Daniel; Marx, Gernot; Tan, Andrew; Junker, Christopher; Van Nuffelen, Marc; Hüter, Lars; Ching, Willy; Michard, Frédéric; Vincent, Jean-Louis

2011-02-01

Second-generation FloTrac software has been shown to reliably measure cardiac output (CO) in cardiac surgical patients. However, concerns have been raised regarding its accuracy in vasoplegic states. The aim of the present multicenter study was to investigate the accuracy of the third-generation software in patients with sepsis, particularly when total systemic vascular resistance (TSVR) is low. Fifty-eight septic patients were included in this prospective observational study in four university-affiliated ICUs. Reference CO was measured by bolus pulmonary thermodilution (iCO) using 3-5 cold saline boluses. Simultaneously, CO was computed from the arterial pressure curve recorded on a computer using the second-generation (CO(G2)) and third-generation (CO(G3)) FloTrac software. CO was also measured by semi-continuous pulmonary thermodilution (CCO). A total of 401 simultaneous measurements of iCO, CO(G2), CO(G3), and CCO were recorded. The mean (95%CI) biases between CO(G2) and iCO, CO(G3) and iCO, and CCO and iCO were -10 (-15 to -5)% [-0.8 (-1.1 to -0.4) L/min], 0 (-4 to 4)% [0 (-0.3 to 0.3) L/min], and 9 (6-13)% [0.7 (0.5-1.0) L/min], respectively. The percentage errors were 29 (20-37)% for CO(G2), 30 (24-37)% for CO(G3), and 28 (22-34)% for CCO. The difference between iCO and CO(G2) was significantly correlated with TSVR (r(2) = 0.37, p < 0.0001). A very weak (r(2) = 0.05) relationship was also observed for the difference between iCO and CO(G3). In patients with sepsis, the third-generation FloTrac software is more accurate, as precise, and less influenced by TSVR than the second-generation software.

A nursing diagnosis approach to the patient awaiting cardiac transplantation.

PubMed

Cardin, S; Clark, S

1985-09-01

The most common reason to perform cardiac transplantation is dilated cardiomyopathy. Alterations in cardiac output secondary to decreased contractility and increased preload and afterload will, over time, lead to progressive deterioration of the patient with this type of end-stage cardiac disease. Heart transplantation is now an accepted therapy for these patients. This article focused on the patient in the period awaiting cardiac transplantation. Five pertinent nursing diagnoses were identified and discussed. A case study approach was utilized to highlight patient problems and nursing interventions.

Endurance training and maximal oxygen consumption with ageing: Role of maximal cardiac output and oxygen extraction.

PubMed

Montero, David; Díaz-Cañestro, Candela

2016-05-01

The increase in maximal oxygen consumption (VO2max) with endurance training is associated with that of maximal cardiac output (Qmax), but not oxygen extraction, in young individuals. Whether such a relationship is altered with ageing remains unclear. Therefore, we sought systematically to review and determine the effect of endurance training on and the associations among VO2max, Qmax and arteriovenous oxygen difference at maximal exercise (Ca-vO2max) in healthy aged individuals. We conducted a systematic search of MEDLINE, Scopus and Web of Science, from their inceptions until May 2015 for articles assessing the effect of endurance training lasting 3 weeks or longer on VO2max and Qmax and/or Ca-vO2max in healthy middle-aged and/or older individuals (mean age ≥40 years). Meta-analyses were performed to determine the standardised mean difference (SMD) in VO2max, Qmax and Ca-vO2max between post and pre-training measurements. Subgroup and meta-regression analyses were used to evaluate the associations among SMDs and potential moderating factors. Sixteen studies were included after systematic review, comprising a total of 153 primarily untrained healthy middle-aged and older subjects (mean age 42-71 years). Endurance training programmes ranged from 8 to 52 weeks of duration. After data pooling, VO2max (SMD 0.89; P < 0.0001) and Qmax (SMD 0.61; P < 0.0001) were increased after endurance training; no heterogeneity among studies was detected. Ca-vO2max was only increased with endurance training interventions lasting more than 12 weeks (SMD 0.62; P = 0.001). In meta-regression, the SMD in Qmax was positively associated with the SMD in VO2max (B = 0.79, P = 0.04). The SMD in Ca-vO2max was not associated with the SMD in VO2max (B = 0.09, P = 0.84). The improvement in VO2max following endurance training is a linear function of Qmax, but not Ca-vO2max, through healthy ageing. © The European Society of Cardiology 2015.

Omega-3 fatty acid supplementation enhances stroke volume and cardiac output during dynamic exercise.

PubMed

Walser, Buddy; Stebbins, Charles L

2008-10-01

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on cardiovascular function. We tested the hypotheses that dietary supplementation with DHA (2 g/day) + EPA (3 g/day) enhances increases in stroke volume (SV) and cardiac output (CO) and decreases in systemic vascular resistance (SVR) during dynamic exercise. Healthy subjects received DHA + EPA (eight men, four women) or safflower oil (six men, three women) for 6 weeks. Both groups performed 20 min of bicycle exercise (10 min each at a low and moderate work intensity) before and after DHA + EPA or safflower oil treatment. Mean arterial pressure (MAP), heart rate (HR), SV, CO, and SVR were assessed before exercise and during both workloads. HR was unaffected by DHA + EPA and MAP was reduced, but only at rest (88 +/- 5 vs. 83 +/- 4 mm Hg). DHA + EPA augmented increases in SV (14.1 +/- 6.3 vs. 32.3 +/- 8.7 ml) and CO (8.5 +/- 1.0 vs. 10.3 +/- 1.2 L/min) and tended to attenuate decreases in SVR (-7.0 +/- 0.6 vs. -10.1 +/- 1.6 mm Hg L(-1) min(-1)) during the moderate workload. Safflower oil treatment had no effects on MAP, HR, SV, CO or SVR at rest or during exercise. DHA + EPA-induced increases in SV and CO imply that dietary supplementation with these fatty acids can increase oxygen delivery during exercise, which may have beneficial clinical implications for individuals with cardiovascular disease and reduced exercise tolerance.

[Summary of the consensus document: "Clinical practice guide for the management of low cardiac output syndrome in the postoperative period of heart surgery"].

PubMed

Pérez Vela, J L; Martín Benitez, J C; Carrasco Gonzalez, M; de la Cal López, M A; Hinojosa Pérez, R; Sagredo Meneses, V; del Nogal Saez, F

2012-05-01

Low cardiac output syndrome is a potential complication in cardiac surgery patients and is associated with increased morbidity and mortality. This guide provides recommendations for the management of these patients, immediately after surgery and following admission to the ICU. The recommendations are grouped into different sections, addressing from the most basic concepts such as definition of the disorder to the different sections of basic and advanced monitoring, and culminating with the complex management of this syndrome. We propose an algorithm for initial management, as well as two others for ventricular failure (predominantly left or right). Most of the recommendations are based on expert consensus, due to the lack of randomized trials of adequate design and sample size in patients of this kind. The quality of evidence and strength of the recommendations were based on the GRADE methodology. The guide is presented as a list of recommendations (with the level of evidence for each recommendation) for each question on the selected topic. For each question, justification of the recommendations is then provided. Copyright © 2011 Elsevier España, S.L. y SEMICYUC. All rights reserved.

Electrical Cardiometry to Monitor Cardiac Output in Preterm Infants with Patent Ductus Arteriosus: A Comparison with Echocardiography.

PubMed

Hsu, Kai-Hsiang; Wu, Tai-Wei; Wu, I-Hsyuan; Lai, Mei-Yin; Hsu, Shih-Yun; Huang, Hsiao-Wen; Mok, Tze-Yee; Lien, Reyin

2017-01-01

Electrical cardiometry (EC) is an impedance-based monitoring that provides noninvasive cardiac output (CO) assessment. Through comparison to transthoracic echocardiography (Echo), the accuracy of EC has been verified. However, left-to-right patent ductus arteriosus (PDA) shunting is a concern because PDA shunts aortic flow to the pulmonary artery and may interfere with EC in measuring CO. To determine the agreement between EC and Echo in preterm infants with a hemodynamically significant PDA (hsPDA). We reviewed our hemodynamic database in which simultaneous CO measurements by Echo and EC (Aesculon®) were recorded. Preterm infants with left-to-right shunting hsPDA were enrolled. A total of 105 paired measurements in 36 preterm infants were compared. Infants' median (range) age and weight at measurement were 27+2 weeks (24+0-33+1) and 1,015 g (518-1,880), with mean (95% CI) ductal diameter 2.11 mm (1.99-2.22) or 2.15 mm/kg (2.00-2.30). Mean COEC and COEcho were 252 ± 32 and 258 ± 45 mL/kg/min, respectively, which demonstrated a moderate correlation and without a significant between-measurement difference. Bland-Altman analysis showed a bias, limits of agreement, and error percentage of -5.3 mL/kg/min, -78.3 to 67.7 mL/kg/min, and 28.6%, respectively. There was a trend of increased bias and error percentage of infants with high CO ≥280 mL/kg/min and supported with high-frequency ventilator. EC and Echo have a wide but clinically acceptable agreement in measuring CO in preterm infants with hsPDA. However, for infants with high CO or ventilated by high-frequency ventilation, interpretation of COEC should be approached with caution. © 2017 S. Karger AG, Basel.

Myocardial Dysfunction and Shock after Cardiac Arrest

PubMed Central

Jentzer, Jacob C.; Chonde, Meshe D.; Dezfulian, Cameron

2015-01-01

Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies. PMID:26421284

Myocardial Dysfunction and Shock after Cardiac Arrest.

PubMed

Jentzer, Jacob C; Chonde, Meshe D; Dezfulian, Cameron

2015-01-01

Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies.

Age-related incidence of desaturation events and the cardiac responses on stroke index, cardiac index, and heart rate measured by continuous bioimpedance noninvasive cardiac output monitoring in infants and children undergoing general anesthesia.

PubMed

King, Michael R; Anderson, T Anthony; Sui, Jinghu; He, Guoluo; Poon, Kwun Yee T; Coté, Charles J

2016-08-01

To assess the effects of desaturation on stroke index (SI), cardiac index (CI), and heart rate (HR) using the ICON continuous noninvasive cardiac output monitor in children undergoing general anesthesia. Retrospective analysis of a prospectively collected data set. Pediatric operating rooms in a tertiary academic medical center. Children younger than 20 years who experienced desaturation while undergoing general anesthesia. All records were retrospectively searched for desaturation events defined as a recorded Spo2 ≤ 90%. We compared the data from the prior 4 minutes (baseline) with mild, moderate, and severe levels of desaturation. The relationship between Spo2 and percent change in SI, CI, and HR from baseline was assessed using a generalized linear model with repeated measures and the least-squares method. Data from 446 patients were reviewed; 38 events were eligible for analysis after exclusions. There were significant decreases in SI at all saturation ranges below 95%: -6.5% (P < .001) for 85%-95%, -8.9% (P = .002) for 71%-84%, and -11% (P < .001) for ≤70%. Based on the result from the regression, Spo2 was associated with change in SI with borderline significance (P = .053) but not that of HR and CI. There was a strong relationship to desaturation events with young age (P < .001), particularly infants younger than 6 months. Events associated with desaturation in children under general anesthesia were significantly associated with decreased SI with a greater effect with lower saturation nadirs. It is unclear if other concurrent events could have also contributed to adverse hemodynamic responses during desaturation. In most children, a compensatory increase in HR generally offsets concurrent decreases in CI. It would appear that bradycardia is a late manifestation of hypoxemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Increased cardiac output and maximal oxygen uptake in response to ten sessions of high intensity interval training.

PubMed

Astorino, Todd A; Edmunds, Ross M; Clark, Amy; King, Leesa; Gallant, Rachael M; Namm, Samantha; Fischer, Anthony; Wood, Kimi A

2018-01-01

Increases in maximal oxygen uptake (VO2max) are widely reported in response to completion of high intensity interval training (HIIT), yet the mechanism explaining this result is poorly understood. This study examined changes in VO2max and cardiac output (CO) in response to 10 sessions of low-volume HIIT. Participants included 30 active men and women (mean age and VO2max=22.9±5.4 years and 39.6±5.6 mL/kg/min) who performed HIIT and 30 men and women (age and VO2max=25.7±4.5 years and 40.7±5.2 mL/kg/min) who served as non-exercising controls (CON). High intensity interval training consisted of 6-10 s bouts of cycling per session at 90-110 percent peak power output (PPO) interspersed with 75 s recovery. Before and after training, progressive cycling to exhaustion was completed during which CO, stroke volume (SV), and heart rate (HR) were estimated using thoracic impedance. To confirm VO2max attainment, a verification test was completed after progressive cycling at a work rate equal to 110%PPO. Data demonstrated significant improvements in VO2max (2.71±0.63 L/min to 2.86±0.63 L/min, P<0.001) and COmax (20.0±3.1 L/min to 21.7±3.2 L/min, P=0.04) via HIIT that were not exhibited in CON. Maximal SV was increased in HIIT (P=0.04) although there was no change in maximal HR (P=0.57). The increase in VO2max seen in response to ten sessions of HIIT is due to improvements in oxygen delivery.

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...

The effects of malnutrition on cardiac function in African children.

PubMed

Silverman, Jonathan A; Chimalizeni, Yamikani; Hawes, Stephen E; Wolf, Elizabeth R; Batra, Maneesh; Khofi, Harriet; Molyneux, Elizabeth M

2016-02-01

Cardiac dysfunction may contribute to high mortality in severely malnourished children. Our objective was to assess the effect of malnutrition on cardiac function in hospitalised African children. Prospective cross-sectional study. Public referral hospital in Blantyre, Malawi. We enrolled 272 stable, hospitalised children ages 6-59 months, with and without WHO-defined severe acute malnutrition. Cardiac index, heart rate, mean arterial pressure, stroke volume index and systemic vascular resistance index were measured by the ultrasound cardiac output monitor (USCOM, New South Wales, Australia). We used linear regression with generalised estimating equations controlling for age, sex and anaemia. Our primary outcome, cardiac index, was similar between those with and without severe malnutrition: difference=0.22 L/min/m(2) (95% CI -0.08 to 0.51). No difference was found in heart rate or stroke volume index. However, mean arterial pressure and systemic vascular resistance index were lower in children with severe malnutrition: difference=-8.6 mm Hg (95% CI -12.7 to -4.6) and difference=-200 dyne s/cm(5)/m(2) (95% CI -320 to -80), respectively. In this largest study to date, we found no significant difference in cardiac function between hospitalised children with and without severe acute malnutrition. Further study is needed to determine if cardiac function is diminished in unstable malnourished children. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Optimal pacing modes after cardiac transplantation: is synchronisation of recipient and donor atria beneficial?

PubMed Central

Parry, Gareth; Malbut, Katie; Dark, John H; Bexton, Rodney S

1992-01-01

Objective—To investigate the response of the transplanted heart to different pacing modes and to synchronisation of the recipient and donor atria in terms of cardiac output at rest. Design—Doppler derived cardiac output measurements at three pacing rates (90/min, 110/min and 130/min) in five pacing modes: right ventricular pacing, donor atrial pacing, recipient-donor synchronous pacing, donor atrial-ventricular sequential pacing, and synchronous recipient-donor atrial-ventricular sequential pacing. Patients—11 healthy cardiac transplant recipients with three pairs of epicardial leads inserted at transplantation. Results—Donor atrial pacing (+11% overall) and donor atrial-ventricular sequential pacing (+8% overall) were significantly better than right ventricular pacing (p < 0·001) at all pacing rates. Synchronised pacing of recipient and donor atrial segments did not confer additional benefit in either atrial or atrial-ventricular sequential modes of pacing in terms of cardiac output at rest at these fixed rates. Conclusions—Atrial pacing or atrial-ventricular sequential pacing appear to be appropriate modes in cardiac transplant recipients. Synchronisation of recipient and donor atrial segments in this study produced no additional benefit. Chronotropic competence in these patients may, however, result in improved exercise capacity and deserves further investigation. PMID:1389737

Determinants of mobile phone output power in a multinational study: implications for exposure assessment.

PubMed

Vrijheid, M; Mann, S; Vecchia, P; Wiart, J; Taki, M; Ardoino, L; Armstrong, B K; Auvinen, A; Bédard, D; Berg-Beckhoff, G; Brown, J; Chetrit, A; Collatz-Christensen, H; Combalot, E; Cook, A; Deltour, I; Feychting, M; Giles, G G; Hepworth, S J; Hours, M; Iavarone, I; Johansen, C; Krewski, D; Kurttio, P; Lagorio, S; Lönn, S; McBride, M; Montestrucq, L; Parslow, R C; Sadetzki, S; Schüz, J; Tynes, T; Woodward, A; Cardis, E

2009-10-01

The output power of a mobile phone is directly related to its radiofrequency (RF) electromagnetic field strength, and may theoretically vary substantially in different networks and phone use circumstances due to power control technologies. To improve indices of RF exposure for epidemiological studies, we assessed determinants of mobile phone output power in a multinational study. More than 500 volunteers in 12 countries used Global System for Mobile communications software-modified phones (GSM SMPs) for approximately 1 month each. The SMPs recorded date, time, and duration of each call, and the frequency band and output power at fixed sampling intervals throughout each call. Questionnaires provided information on the typical circumstances of an individual's phone use. Linear regression models were used to analyse the influence of possible explanatory variables on the average output power and the percentage call time at maximum power for each call. Measurements of over 60,000 phone calls showed that the average output power was approximately 50% of the maximum, and that output power varied by a factor of up to 2 to 3 between study centres and network operators. Maximum power was used during a considerable proportion of call time (39% on average). Output power decreased with increasing call duration, but showed little variation in relation to reported frequency of use while in a moving vehicle or inside buildings. Higher output powers for rural compared with urban use of the SMP were observed principally in Sweden where the study covered very sparsely populated areas. Average power levels are substantially higher than the minimum levels theoretically achievable in GSM networks. Exposure indices could be improved by accounting for average power levels of different telecommunications systems. There appears to be little value in gathering information on circumstances of phone use other than use in very sparsely populated regions.

Comparison of two methods for cardiac output measurement in critically ill patients.

PubMed

Saraceni, E; Rossi, S; Persona, P; Dan, M; Rizzi, S; Meroni, M; Ori, C

2011-05-01

The aim of recent haemodynamic monitoring has been to obtain continuous and reliable measures of cardiac output (CO) and indices of preload responsiveness. Many of these methods are based on the arterial pressure waveform analysis. The aim of our study was to assess the accuracy of CO measurements obtained by FloTrac/Vigileo, software version 1.07 and the new version 1.10 (Edwards Lifesciences LLC, Irvine, CA, USA), compared with CO measurements obtained by bolus thermodilution by pulmonary artery catheterization (PAC) in the intensive care setting. In 21 critically ill patients (enrolled in two University Hospitals), requiring invasive haemodynamic monitoring, PAC and FloTrac/Vigileo transducers connected to the arterial pressure line were placed. Simultaneous measurements of CO by two methods (FloTrac/Vigileo and thermodilution) were obtained three times a day for 3 consecutive days, when possible. The level of concordance between the two methods was assessed by the procedure suggested by Bland and Altman. One hundred and forty-one pairs of measurements (provided by thermodilution and by both 1.07 and 1.10 FloTrac/Vigileo versions) were obtained in 21 patients (seven of them were trauma patients) with a mean (sd) age of 59 (16) yr. The Pearson product moment coefficient was 0.62 (P<0.001). The bias was -0.18 litre min(-1). The limits of agreement were 4.54 and -4.90 litre min(-1), respectively. Our data show a poor level of concordance between measures provided by the two methods. We found an underestimation of CO values measured with the 1.07 software version of FloTrac for supranormal values of CO. The new software (1.10) has been improved in order to correct this bias; however, its reliability is still poor. On the basis of our data, we can therefore conclude that both software versions of FloTrac/Vigileo did not still provide reliable estimation of CO in our intensive care unit setting.

Noninvasive Cardiac Output Estimation by Inert Gas Rebreathing in Mechanically Ventilated Pediatric Patients.

PubMed

Perak, Amanda M; Opotowsky, Alexander R; Walsh, Brian K; Esch, Jesse J; DiNardo, James A; Kussman, Barry D; Porras, Diego; Rhodes, Jonathan

2016-10-01

To assess the feasibility and accuracy of inert gas rebreathing (IGR) pulmonary blood flow (Qp) estimation in mechanically ventilated pediatric patients, potentially providing real-time noninvasive estimates of cardiac output. In mechanically ventilated patients in the pediatric catheterization laboratory, we compared IGR Qp with Qp estimates based upon the Fick equation using measured oxygen consumption (VO2) (FickTrue); for context, we compared FickTrue with a standard clinical short-cut, replacing measured with assumed VO2 in the Fick equation (FickLaFarge, FickLundell, FickSeckeler). IGR Qp and breath-by-breath VO2 were measured using the Innocor device. Sampled pulmonary arterial and venous saturations and hemoglobin concentration were used for Fick calculations. Qp estimates were compared using Bland-Altman agreement and Spearman correlation. The final analysis included 18 patients aged 4-23 years with weight >15 kg. Compared with the reference FickTrue, IGR Qp estimates correlated best and had the least systematic bias and narrowest 95% limits of agreement (results presented as mean bias ±95% limits of agreement): IGR -0.2 ± 1.1 L/min, r = 0.90; FickLaFarge +0.7 ± 2.2 L/min, r = 0.80; FickLundell +1.6 ± 2.9 L/min, r = 0.83; FickSeckeler +0.8 ± 2.5 L/min, r = 0.83. IGR estimation of Qp is feasible in mechanically ventilated patients weighing >15 kg, and agreement with FickTrue Qp estimates is better for IGR than for other Fick Qp estimates commonly used in pediatric catheterization. IGR is an attractive option for bedside monitoring of Qp in mechanically ventilated children. Copyright © 2016 Elsevier Inc. All rights reserved.

Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.

PubMed

Hasin, Tal; Huebner, Marianne; Li, Zhuo; Brown, Daniel; Stulak, John M; Boilson, Barry A; Joyce, Lyle; Pereira, Naveen L; Kushwaha, Sudhir S; Park, Soon J

2014-01-01

Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ≥90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.

Robotic cardiac surgery: an anaesthetic challenge.

PubMed

Wang, Gang; Gao, Changqing

2014-08-01

Robotic cardiac surgery with the da Vinci robotic surgical system offers the benefits of a minimally invasive procedure, including a smaller incision and scar, reduced risk of infection, less pain and trauma, less bleeding and blood transfusion requirements, shorter hospital stay and decreased recovery time. Robotic cardiac surgery includes extracardiac and intracardiac procedures. Extracardiac procedures are often performed on a beating heart. Intracardiac procedures require the aid of peripheral cardiopulmonary bypass via a minithoracotomy. Robotic cardiac surgery, however, poses challenges to the anaesthetist, as the obligatory one-lung ventilation (OLV) and CO2 insufflation may reduce cardiac output and increase pulmonary vascular resistance, potentially resulting in hypoxaemia and haemodynamic compromise. In addition, surgery requires appropriate positioning of specialised cannulae such as an endopulmonary vent, endocoronary sinus catheter, and endoaortic clamp catheter under the guidance of transoesophageal echocardiography. Therefore, cardiac anaesthetists should have a working knowledge of these systems, OLV and haemodynamic support. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Effect of hypokinesia on cardiac contractile function and nervous regulation of the heart

NASA Technical Reports Server (NTRS)

Meyerson, F. Z.; Kapelko, V. I.; Gorina, M. S.; Shchegolkov, A. N.; Larinov, N. P.

1980-01-01

Longterm hypokinesia caused cardiac deadaptation in rabbits, which resulted in the diminishing of the left ventricular rate of contraction and relaxation, joined later by decreased vascular resistance. As a results, the ejection rate as well as stroke volume and cardiac output were normal. The decrease of the relaxation speed was more obvious at a high heart rate and results in shortening of the diastolic pause and diminishing of cardiac output. Hearts of the hypokinetic animals were characterized by normal maximal pressure developed by a unit of muccardial mass aorta clamping, decreased adrenoreactivity, and increased cholinoreactivity. This complex of changes is contrary to changes observed in adaptation to exercise, but is similar to changes observed in compensatory hypertrophy of the heart.

Prophylactic milrinone for the prevention of low cardiac output syndrome and mortality in children undergoing surgery for congenital heart disease.

PubMed

Burkhardt, Barbara E U; Rücker, Gerta; Stiller, Brigitte

2015-03-25

Children with congenital heart disease often undergo heart surgery at a young age. They are at risk for postoperative low cardiac output syndrome (LCOS) or death. Milrinone may be used to provide inotropic and vasodilatory support during the immediate postoperative period. This review examines the effectiveness of prophylactic postoperative use of milrinone to prevent LCOS or death in children having undergone surgery for congenital heart disease. Electronic and manual literature searches were performed to identify randomised controlled trials. We searched CENTRAL, MEDLINE, EMBASE and Web of Science in February 2014 and conducted a top-up search in September 2014 as well as clinical trial registries and reference lists of published studies. We did not apply any language restrictions. Only randomised controlled trials were selected for analysis. We considered studies with newborn infants, infants, toddlers, and children up to 12 years of age. Two review authors independently extracted data according to a pre-defined protocol. We obtained additional information from all study authors. Three of the five included studies compared milrinone versus levosimendan, one study compared milrinone with placebo, and one compared milrinone verus dobutamine, with 101, 242, and 50 participants, respectively. Three trials were at low risk of bias while two were at higher risk of bias. The number and definitions of outcomes were non-uniform as well. In one study comparing two doses of milrinone and placebo, there was some evidence in an overall comparison of milrinone versus placebo that milrinone lowered risk for LCOS (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.28 to 0.96; 227 participants). The results from two small studies do not provide enough information to determine whether milrinone increases the risk of LCOS when compared to levosimendan (RR 1.22, 95% CI 0.32 to 4.65; 59 participants). Mortality rates in the studies were low, and there was insufficient evidence to

Work and power outputs determined from pedalling and flywheel friction forces during brief maximal exertion on a cycle ergometer.

PubMed

Hibi, N; Fujinaga, H; Ishii, K

1996-01-01

Work and power outputs during short-term, maximal exertion on a friction loaded cycle ergometer are usually calculated from the friction force applied to the flywheel. The inertia of the flywheel is sometimes taken into consideration, but the effects of internal resistances and other factors have been ignored. The purpose of this study was to estimate their effects by comparing work or power output determined from the force exerted on the pedals (pedalling force) with work or power output determined from the friction force and the moment of inertia of the rotational parts. A group of 22 male college students accelerated a cycle ergometer as rapidly as possible for 3 s. The total work output determined from the pedalling force (TWp) was significantly greater than that calculated from the friction force and the moment of inertia (TWf). Power output determined from the pedalling force during each pedal stroke (SPp) was also significantly greater than that calculated from the friction force and the moment of inertia. Percentage difference (% diff), defined by % diff = ¿(TWp - TWf)/TWf¿ x 100, ranged from 16.8% to 49.3% with a mean value of 30.8 (SD 9.1)%. It was observed that % diff values were higher in subjects with greater TWp or greater maximal SPp. These results would indicate that internal resistances and other factors, such as the deformation of the chain and the vibrations of the entire system, may have significant effects on the measurements of work and power outputs. The effects appear to depend on the magnitudes of pedalling force and pedal velocity.

Influence of body position on hemodynamics in patients with ischemic heart disease undergoing cardiac surgery.

PubMed

Mekis, Dusan; Kamenik, Mirt

2010-05-01

The cardiovascular response to decreased or increased preload in high-risk patients with ischemic heart disease enables us to understand the physiologic response to hemorrhage and its treatment. Although numerous studies have failed to show its effectiveness, the head-down position is still widely used to treat patients with hypotension and shock. The aim of our study was to evaluate the influence of body position on hemodynamics in high-risk patients undergoing coronary artery bypass graft surgery. In 16 patients with ischemic hearth disease and poor left ventricular function undergoing coronary artery bypass graft surgery, we measured cardiac output with thermodilution, arterial pressure, central venous pressure (CVP), pulmonary artery wedge pressure (PAWP) and heart rate in three different body positions: the horizontal position, 20 degrees head-up position, 20 degrees head-down position and back in the horizontal position. The measurements were made before and after cardiac surgery. Before skin incision the change from horizontal to 20 degrees head-up position led to a nonsignificant decrease in cardiac output and a significant decrease in mean arterial pressure, CVP and PAWP. The change from 20 degrees head-up to 20 degrees head-down position led to a significant increase in cardiac output, mean arterial pressure, CVP and PAWP. After skin closure the change from horizontal to 20 degrees head-up position led to a nonsignificant decrease in cardiac output and mean arterial pressure and a significant decrease CVP and PAWP. The change from 20 degrees head-up to 20 degrees head-down position led to a nonsignificant increase in cardiac output and a significant increase in mean arterial pressure, CVP and PAWP. There were no significant changes in heart rate during the changes in position before or after surgery. The results of our study showed a hemodynamic response similar to hemorrhage after placing the patients in a 20 degrees head-up position and improving

Testosterone receptor blockade after trauma-hemorrhage improves cardiac and hepatic functions in males.

PubMed

Remmers, D E; Wang, P; Cioffi, W G; Bland, K I; Chaudry, I H

1997-12-01

Although studies have shown that testosterone receptor blockade with flutamide after hemorrhage restores the depressed immune function, it remains unknown whether administration of flutamide following trauma and hemorrhage and resuscitation has any salutary effects on the depressed cardiovascular and hepatocellular functions. To study this, male rats underwent a laparotomy (representing trauma) and were then bled and maintained at a mean arterial pressure (MAP) of 40 mmHg until the animals could not maintain this pressure. Ringer lactate was given to maintain a MAP of 40 mmHg until 40% of the maximal shed blood volume was returned in the form of Ringer lactate. The rats were then resuscitated with four times the shed blood volume in the form of Ringer lactate over 60 min. Flutamide (25 mg/kg) or an equal volume of the vehicle propanediol was injected subcutaneously 15 min before the end of resuscitation. Various in vivo heart performance parameters (e.g., maximal rate of the pressure increase or decrease), cardiac output, and hepatocellular function (i.e., the maximum velocity and the overall efficiency of indocyanine green clearance) were determined at 20 h after resuscitation. Additionally, hepatic microvascular blood flow (HMBF) was determined using a laser Doppler flowmeter. The results indicate that left ventricular performance, cardiac output, HMBF, and hepatocellular function decreased significantly at 20 h after the completion of trauma, hemorrhage, and resuscitation. Administration of the testosterone receptor blocker flutamide, however, significantly improved cardiac performance, HMBF, and hepatocellular function. Thus flutamide appears to be a novel and useful adjunct for improving cardiovascular and hepatocellular functions in males following trauma and hemorrhagic shock.

Roles of PDE1 in Pathological Cardiac Remodeling and Dysfunction.

PubMed

Chen, Si; Knight, Walter E; Yan, Chen

2018-04-23

Pathological cardiac hypertrophy and dysfunction is a response to various stress stimuli and can result in reduced cardiac output and heart failure. Cyclic nucleotide signaling regulates several cardiac functions including contractility, remodeling, and fibrosis. Cyclic nucleotide phosphodiesterases (PDEs), by catalyzing the hydrolysis of cyclic nucleotides, are critical in the homeostasis of intracellular cyclic nucleotide signaling and hold great therapeutic potential as drug targets. Recent studies have revealed that the inhibition of the PDE family member PDE1 plays a protective role in pathological cardiac remodeling and dysfunction by the modulation of distinct cyclic nucleotide signaling pathways. This review summarizes recent key findings regarding the roles of PDE1 in the cardiac system that can lead to a better understanding of its therapeutic potential.

Computational Quantification of the Cardiac Energy Consumption during Intra-Aortic Balloon Pumping Using a Cardiac Electromechanics Model

PubMed Central

Lim, Ki Moo; Lee, Jeong Sang; Gyeong, Min-Soo; Choi, Jae-Sung; Choi, Seong Wook

2013-01-01

To quantify the reduction in workload during intra-aortic balloon pump (IABP) therapy, indirect parameters are used, such as the mean arterial pressure during diastole, product of heart rate and peak systolic pressure, and pressure-volume area. Therefore, we investigated the cardiac energy consumption during IABP therapy using a cardiac electromechanics model. We incorporated an IABP function into a previously developed electromechanical model of the ventricle with a lumped model of the circulatory system and investigated the cardiac energy consumption at different IABP inflation volumes. When the IABP was used at inflation level 5, the cardiac output and stroke volume increased 11%, the ejection fraction increased 21%, the stroke work decreased 1%, the mean arterial pressure increased 10%, and the ATP consumption decreased 12%. These results show that although the ATP consumption is decreased significantly, stroke work is decreased only slightly, which indicates that the IABP helps the failed ventricle to pump blood efficiently. PMID:23341718

Computational quantification of the cardiac energy consumption during intra-aortic balloon pumping using a cardiac electromechanics model.

PubMed

Lim, Ki Moo; Lee, Jeong Sang; Gyeong, Min-Soo; Choi, Jae-Sung; Choi, Seong Wook; Shim, Eun Bo

2013-01-01

To quantify the reduction in workload during intra-aortic balloon pump (IABP) therapy, indirect parameters are used, such as the mean arterial pressure during diastole, product of heart rate and peak systolic pressure, and pressure-volume area. Therefore, we investigated the cardiac energy consumption during IABP therapy using a cardiac electromechanics model. We incorporated an IABP function into a previously developed electromechanical model of the ventricle with a lumped model of the circulatory system and investigated the cardiac energy consumption at different IABP inflation volumes. When the IABP was used at inflation level 5, the cardiac output and stroke volume increased 11%, the ejection fraction increased 21%, the stroke work decreased 1%, the mean arterial pressure increased 10%, and the ATP consumption decreased 12%. These results show that although the ATP consumption is decreased significantly, stroke work is decreased only slightly, which indicates that the IABP helps the failed ventricle to pump blood efficiently.

Cardiac Iron Determines Cardiac T2*, T2, and T1 in the Gerbil Model of Iron Cardiomyopathy

PubMed Central

Wood, John C.; Otto-Duessel, Maya; Aguilar, Michelle; Nick, Hanspeter; Nelson, Marvin D.; Coates, Thomas D.; Pollack, Harvey; Moats, Rex

2010-01-01

Background Transfusional therapy for thalassemia major and sickle cell disease can lead to iron deposition and damage to the heart, liver, and endocrine organs. Iron causes the MRI parameters T1, T2, and T2* to shorten in these organs, which creates a potential mechanism for iron quantification. However, because of the danger and variability of cardiac biopsy, tissue validation of cardiac iron estimates by MRI has not been performed. In this study, we demonstrate that iron produces similar T1, T2, and T2* changes in the heart and liver using a gerbil iron-overload model. Methods and Results Twelve gerbils underwent iron dextran loading (200 mg · kg−1 · wk−1) from 2 to 14 weeks; 5 age-matched controls were studied as well. Animals had in vivo assessment of cardiac T2* and hepatic T2 and T2* and postmortem assessment of cardiac and hepatic T1 and T2. Relaxation measurements were performed in a clinical 1.5-T magnet and a 60-MHz nuclear magnetic resonance relaxometer. Cardiac and liver iron concentrations rose linearly with administered dose. Cardiac 1/T2*, 1/T2, and 1/T1 rose linearly with cardiac iron concentration. Liver 1/T2*, 1/T2, and 1/T1 also rose linearly, proportional to hepatic iron concentration. Liver and heart calibrations were similar on a dry-weight basis. Conclusions MRI measurements of cardiac T2 and T2* can be used to quantify cardiac iron. The similarity of liver and cardiac iron calibration curves in the gerbil suggests that extrapolation of human liver calibration curves to heart may be a rational approximation in humans. PMID:16027257

The left ventricle as a mechanical engine: from Leonardo da Vinci to the echocardiographic assessment of peak power output-to-left ventricular mass.

PubMed

Dini, Frank L; Guarini, Giacinta; Ballo, Piercarlo; Carluccio, Erberto; Maiello, Maria; Capozza, Paola; Innelli, Pasquale; Rosa, Gian M; Palmiero, Pasquale; Galderisi, Maurizio; Razzolini, Renato; Nodari, Savina

2013-03-01

The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed.

Content validation of the operational definitions of the nursing diagnoses of activity intolerance, excess fluid volume, and decreased cardiac output in patients with heart failure.

PubMed

de Souza, Vanessa; Zeitoun, Sandra Salloum; Lopes, Camila Takao; de Oliveira, Ana Paula Dias; Lopes, Juliana de Lima; de Barros, Alba Lucia Botura Leite

2014-06-01

To consensually validate the operational definitions of the nursing diagnoses activity intolerance, excessive fluid volume, and decreased cardiac output in patients with decompensated heart failure. Consensual validation was performed in two stages: analogy by similarity of defining characteristics, and development of operational definitions and validation with experts. A total of 38 defining characteristics were found. Operational definitions were developed and content-validated. One hundred percent of agreement was achieved among the seven experts after five rounds. "Ascites" was added in the nursing diagnosis excessive fluid volume. The consensual validation improves interpretation of human response, grounding the selection of nursing interventions and contributing to improved nursing outcomes. Support the assessment of patients with decompensated heart failure. © 2013 NANDA International.

Cardiac Biomarkers: a Focus on Cardiac Regeneration

PubMed Central

Forough, Reza; Scarcello, Catherine; Perkins, Matthew

2011-01-01

Historically, biomarkers have been used in two major ways to maintain and improve better health status: first, for diagnostic purposes, and second, as specific targets to treat various diseases. A new era in treatment and even cure for the some diseases using reprograming of somatic cells is about to be born. In this approach, scientists are successfully taking human skin cells (previously considered terminally-differentiated cells) and re-programming them into functional cardiac myocytes and other cell types in vitro. A cell reprograming approach for treatment of cardiovascular diseases will revolutionize the field of medicine and significantly expand the human lifetime. Availability of a comprehensive catalogue for cardiac biomarkers is necessary for developing cell reprograming modalities to treat cardiac diseases, as well as for determining the progress of reprogrammed cells as they become cardiac cells. In this review, we present a comprehensive survey of the cardiac biomarkers currently known. PMID:23074366

Algerian medical teachers' research output and its determinants during the 2000-2009 decade.

PubMed

Bezzaoucha, A; Atif, M L; Bouamra, A; El Kebboub, A; Benzerga, M; Ben Abdelaziz, A; Soulimane, A; Ladner, J; Borgès Da Silva, G; Meguenni, K; Quessar, A; Heroual, N; Bouguizi, A; Boussouf, N; Makhlouf, F; Lamdjadani, N; Tibiche, A; Abbassene, S; Regagba, D; Benameur, M

2014-02-01

Publications are the primary output of scientific research. We conducted a national study to quantify Algerian medical teachers' research output and identify its determinants during the 2000-2009 decade. The American Medline database and the French Pascal database were used. A publication was eligible only if the lead author was an Algerian medical teacher (in medicine, pharmacy, or dentistry) working in Algeria. The same questionnaire was completed by cases (teachers who were first authors of an original article during the study period) and randomly selected controls. Logistic regression analysis was used to identify factors related to research output. A total of 79 original articles (42.2% of publications) were retrieved, a quarter of which were listed in Pascal alone. The publication rate was 2.6 original articles per 1000 teachers per year. The journals that published these original articles had a median impact factor of 0.83. The ability to publish an original article was 4.3 times higher if the teacher had undergone training in biostatistics and/or epidemiology (adjusted odds ratio [aOR]=4.31, 95% confidence interval [CI]: 1.79-10.38). A promotion evaluation grid that did not encourage writing (aOR=3.44, 95% CI: 1.42-8.33), a doctoral thesis, seniority, foreign collaboration, and English language proficiency were found to be associated with publication output. Algerian medical teachers' research output was particularly low. Replacing the current promotion grid with a grid that promotes writing, developing abilities to read and write articles and developing English language proficiency are likely to improve this situation. Copyright © 2014. Published by Elsevier Masson SAS.

Effects of oxygen inhalation on cardiac output, coronary blood flow and oxygen delivery in healthy individuals, assessed with MRI.

PubMed

Bodetoft, Stefan; Carlsson, Marcus; Arheden, Håkan; Ekelund, Ulf

2011-02-01

Oxygen (O2) is a cornerstone in the treatment of critically ill patients, and the guidelines prescribe 10-15 l of O2/min even to those who are initially normoxic. Studies using indirect or invasive methods suggest, however, that supplemental O2 may have negative cardiovascular effects. The aim of this study was to test the hypothesis, using noninvasive cardiac magnetic resonance imaging, that inhaled supplemental O2 decreases cardiac output (CO) and coronary blood flow in healthy individuals. Sixteen healthy individuals inhaled O2 at 1, 8 and 15 l/min through a standard reservoir bag mask. A 1.5 T magnetic resonance imaging scanner was used to measure stroke volume, CO and coronary sinus blood flow. Left ventricular (LV) perfusion was calculated as coronary sinus blood flow/LV mass. The O2 response was dose-dependent. At 15 l of O2/min, blood partial pressure of O2 increased from an average 11.7 to 51.0 kPa with no significant changes in blood partial pressure of CO2 or arterial blood pressure. At the same dose, LV perfusion decreased by 23% (P=0.005) and CO decreased by 10% (P=0.003) owing to a decrease in heart rate (by 9%, P<0.002), with no significant changes in stroke volume or LV dimensions. Owing to the decreased CO and LV perfusion, systemic and coronary O2 delivery fell by 4 and 11% at 8 l of O2/min, despite the increased blood oxygen content. Our data indicate that O2 administration decreases CO, LV perfusion and systemic and coronary O2 delivery in healthy individuals. Further research should address the effects of O2 therapy in normoxic patients.

Reliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.

PubMed

Ji, Fuhai; Li, Jian; Fleming, Neal; Rose, David; Liu, Hong

2015-08-01

Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. We performed a prospective observational study to assess the effects of phenylephrine administration on CO values measured by the 3rd and 4th generation FloTrac algorithms. 54 patients were enrolled in this study. We used the Nexfin, a pulse contour method shown to be insensitive to vasopressor administration, as the reference method. Radial arterial pressures were recorded continuously in patients undergoing surgery. Phenylephrine administration times were documented. Arterial pressure recordings were subsequently analyzed offline using three different pulse contour analysis algorithms: FloTrac 3rd generation (G3), FloTrac 4th generation (G4), and Nexfin (nf). One minute of hemodynamic measurements was analyzed immediately before phenylephrine administration and then repeated when the mean arterial pressure peaked. A total of 157 (4.6 ± 3.2 per patient, range 1-15) paired sets of hemodynamic recordings were analyzed. Phenylephrine induced a significant increase in stroke volume (SV) and CO with the FloTrac G3, but not with FloTrac G4 or Nexfin algorithms. Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine.

Determination of cardiac size from chest roentgenograms following Skylab missions

NASA Technical Reports Server (NTRS)

Nicogossian, A. E.; Hoffler, G. W.; Johnson, R. L.; Gowen, R. J.

1974-01-01

Decreased cardiothoracic transverse diameter ratios following Mercury, Gemini and Apollo space flights have been reported previously. To evaluate further changes in cardiac size, standard posteroanterior chest films in systole and diastole were obtained before flight and within a few hours after recovery on each of the Skylab astronauts. Postflight chest X-rays were visually compared to the preflight roentgenograms for possible changes in pulmonary vasculature, lung parenchyma, bony or soft tissue structures. From these roentgenograms the following measurements were obtained: cardiac and thoracic transverse diameters, cardiothoracic transverse diameter ratio, cardiac area from the product of both diagonal diameters, cardiac silhouette area by planimetry, thoracic cage area and cardiothoracic area ratio. The postflight frontal cardiac silhouette sizes were significantly decreased when compared with the respective preflight values (P0.05 or 0.01). The observed changes are thought to be related to postflight decrease in the intracardiac chamber volume.

Effects of levosimendan on mortality in patients undergoing cardiac surgery: A systematic review and meta-analysis.

PubMed

Chen, Peili; Wu, Xiaoqiang; Wang, Zhiwei; Li, Zhenya; Tian, Xiangyong; Wang, Junpeng; Yan, Tianzhong

2018-06-01

We sought to determine the impact of levosimendan on mortality following cardiac surgery based on large-scale randomized controlled trials (RCTs). We searched PubMed, Web of Science, Cochrane databases, and ClinicalTrials.gov for RCTs published up to December 2017, on levosimendan for patients undergoing cardiac surgery. A total of 25 RCTs enrolling 2960 patients met the inclusion criteria; data from 15 placebo-controlled randomized trials were included for meta-analysis. Pooled analysis showed that the all-cause mortality rate was 6.4% (71 of 1106) in the levosimendan group and 8.4% (93 of 1108) in the placebo group (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.55-1.04; P = 0.09). There were no significant differences between the two groups in the rates of myocardial infarction (OR: 0.91; 95% CI, 0.68-1.21; P = 0.52), serious adverse events (OR: 0.84; 95% CI, 0.66-1.07; P = 0.17), hypotension (OR: 1.69; 95% CI, 0.94-3.03; P = 0.08), and low cardiac output syndrome (OR: 0.47; 95% CI, 0.22-1.02; P = 0.05). Levosimendan did not result in a reduction in mortality in adult cardiac surgery patients. Well designed, adequately powered, multicenter trials are necessary to determine the role of levosimendan in adult cardiac surgery. © 2018 The Authors. Journal of Cardiac Surgery Published by Wiley Periodicals Inc.

High-throughput cardiac science on the Grid.

PubMed

Abramson, David; Bernabeu, Miguel O; Bethwaite, Blair; Burrage, Kevin; Corrias, Alberto; Enticott, Colin; Garic, Slavisa; Gavaghan, David; Peachey, Tom; Pitt-Francis, J; Pueyo, E; Rodriguez, Blanca; Sher, Anna; Tan, Jefferson

2010-08-28

Cardiac electrophysiology is a mature discipline, with the first model of a cardiac cell action potential having been developed in 1962. Current models range from single ion channels, through very complex models of individual cardiac cells, to geometrically and anatomically detailed models of the electrical activity in whole ventricles. A critical issue for model developers is how to choose parameters that allow the model to faithfully reproduce observed physiological effects without over-fitting. In this paper, we discuss the use of a parametric modelling toolkit, called Nimrod, that makes it possible both to explore model behaviour as parameters are changed and also to tune parameters by optimizing model output. Importantly, Nimrod leverages computers on the Grid, accelerating experiments by using available high-performance platforms. We illustrate the use of Nimrod with two case studies, one at the cardiac tissue level and one at the cellular level.

Do interindividual differences in cardiac output during submaximal exercise explain differences in exercising muscle oxygenation and ratings of perceived exertion?

PubMed

Bentley, Robert F; Jones, Joshua H; Hirai, Daniel M; Zelt, Joel T; Giles, Matthew D; Raleigh, James P; Quadrilatero, Joe; Gurd, Brendon J; Neder, J Alberto; Tschakovsky, Michael E

2018-01-01

Considerable interindividual differences in the Q˙-V˙O2 relationship during exercise have been documented but implications for submaximal exercise tolerance have not been considered. We tested the hypothesis that these interindividual differences were associated with differences in exercising muscle deoxygenation and ratings of perceived exertion (RPE) across a range of submaximal exercise intensities. A total of 31 (21 ± 3 years) healthy recreationally active males performed an incremental exercise test to exhaustion 24 h following a resting muscle biopsy. Cardiac output (Q˙ L/min; inert gas rebreathe), oxygen uptake (V˙O2 L/min; breath-by-breath pulmonary gas exchange), quadriceps saturation (near infrared spectroscopy) and exercise tolerance (6-20; Borg Scale RPE) were measured. The Q˙-V˙O2 relationship from 40 to 160 W was used to partition individuals post hoc into higher (n = 10; 6.3 ± 0.4) versus lower (n = 10; 3.7 ± 0.4, P < 0.001) responders. The Q˙-V˙O2 difference between responder types was not explained by arterial oxygen content differences (P = 0.5) or peripheral skeletal muscle characteristics (P from 0.1 to 0.8) but was strongly associated with stroke volume (P < 0.05). Despite considerable Q˙-V˙O2 difference between groups, no difference in quadriceps deoxygenation was observed during exercise (all P > 0.4). Lower cardiac responders had greater leg (P = 0.027) and whole body (P = 0.03) RPE only at 185 W, but this represented a higher %peak V˙O2 in lower cardiac responders (87 ± 15% vs. 66 ± 12%, P = 0.005). Substantially lower Q˙-V˙O2 in the lower responder group did not result in altered RPE or exercising muscle deoxygenation. This suggests substantial recruitment of blood flow redistribution in the lower responder group as part of protecting matching of exercising muscle oxygen delivery to demand. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The

Extracorporeal cardiopulmonary resuscitation for blunt cardiac rupture.

PubMed

Kudo, Shunsuke; Tanaka, Keiji; Okada, Kunihiko; Takemura, Takahiro

2017-11-01

Extracorporeal cardiopulmonary resuscitation (ECPR) followed by operating room sternotomy, rather than resuscitative thoracotomy, might be life-saving for patients with blunt cardiac rupture and cardiac arrest who do not have multiple severe traumatic injuries. A 49-year-old man was injured in a vehicle crash and transferred to the emergency department. On admission, he was hemodynamically stable, but a plain chest radiograph revealed a widened mediastinum, and echocardiography revealed hemopericardium. A computed tomography scan revealed hemopericardium and mediastinal hematoma, without other severe traumatic injuries. However, the patient's pulse was lost soon after he was transferred to the intensive care unit, and cardiopulmonary resuscitation was initiated. We initiated ECPR using femorofemoral veno-arterial extracorporeal membrane oxygenation (ECMO) with heparin administration, which achieved hemodynamic stability. He was transferred to the operating room for sternotomy and cardiac repair. Right ventricular rupture and pericardial sac laceration were identified intraoperatively, and cardiac repair was performed. After repairing the cardiac rupture, the cardiac output recovered spontaneously, and ECMO was discontinued intraoperatively. The patient recovered fully and was discharged from the hospital on postoperative day 7. In this patient, ECPR rapidly restored brain perfusion and provided enough time to perform operating room sternotomy, allowing for good surgical exposure of the heart. Moreover, open cardiac massage was unnecessary. ECPR with sternotomy and cardiac repair is advisable for patients with blunt cardiac rupture and cardiac arrest who do not have severe multiple traumatic injuries. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed Central

2014-01-01

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 μg.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) = θCL x (BWi)3/4 and q0(BWi) = θq0 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

Traction force microscopy of engineered cardiac tissues.

PubMed

Pasqualini, Francesco Silvio; Agarwal, Ashutosh; O'Connor, Blakely Bussie; Liu, Qihan; Sheehy, Sean P; Parker, Kevin Kit

2018-01-01

Cardiac tissue development and pathology have been shown to depend sensitively on microenvironmental mechanical factors, such as extracellular matrix stiffness, in both in vivo and in vitro systems. We present a novel quantitative approach to assess cardiac structure and function by extending the classical traction force microscopy technique to tissue-level preparations. Using this system, we investigated the relationship between contractile proficiency and metabolism in neonate rat ventricular myocytes (NRVM) cultured on gels with stiffness mimicking soft immature (1 kPa), normal healthy (13 kPa), and stiff diseased (90 kPa) cardiac microenvironments. We found that tissues engineered on the softest gels generated the least amount of stress and had the smallest work output. Conversely, cardiomyocytes in tissues engineered on healthy- and disease-mimicking gels generated significantly higher stresses, with the maximal contractile work measured in NRVM engineered on gels of normal stiffness. Interestingly, although tissues on soft gels exhibited poor stress generation and work production, their basal metabolic respiration rate was significantly more elevated than in other groups, suggesting a highly ineffective coupling between energy production and contractile work output. Our novel platform can thus be utilized to quantitatively assess the mechanotransduction pathways that initiate tissue-level structural and functional remodeling in response to substrate stiffness.

Transesophageal Echocardiography, 3-Dimensional and Speckle Tracking Together as Sensitive Markers for Early Outcome in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery.

PubMed

Kumar, Alok; Puri, Goverdhan Dutt; Bahl, Ajay

2017-10-01

Speckle tracking, when combined with 3-dimensional (3D) left ventricular ejection fraction, might prove to be a more sensitive marker for postoperative ventricular dysfunction. This study investigated early outcomes in a cohort of patients with left ventricular dysfunction undergoing cardiac surgery. Prospective, blinded, observational study. University hospital; single institution. The study comprised 73 adult patients with left ventricular ejection fraction <50% undergoing cardiac surgery using cardiopulmonary bypass. Routine transesophageal echocardiography before and after bypass. Global longitudinal strain using speckle tracking and 3D left ventricular ejection fraction were computed using transesophageal echocardiography. Mean prebypass global longitudinal strain and 3D left ventricle ejection fraction were significantly lower in patients with postoperative low-cardiac-output syndrome compared with patients who did not develop low cardiac output (global longitudinal strain -7.5% v -10.7% and 3D left ventricular ejection fraction 29% v 39%, respectively; p < 0.0001). The cut-off value of global longitudinal strain predicting postoperative low-cardiac-output syndrome was -6%, with 95% sensitivity and 68% specificity; and 3D left ventricular ejection fraction was 19% with 98% sensitivity and 81% specificity. Preoperative left ventricular global longitudinal strain (-6%) and 3D left ventricular ejection fraction (19%) together could act as predictor of postoperative low-cardiac-output states with high sensitivity (99.9%) in patients undergoing cardiac surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

Ventilation and gas exchange management after cardiac arrest.

PubMed

Sutherasan, Yuda; Raimondo, Pasquale; Pelosi, Paolo

2015-12-01

For several decades, physicians had integrated several interventions aiming to improve the outcomes in post-cardiac arrest patients. However, the mortality rate after cardiac arrest is still as high as 50%. Post-cardiac arrest syndrome is associated with high morbidity and mortality due to not only poor neurological outcome and cardiovascular failure but also respiratory dysfunction. To minimize ventilator-associated lung injury, protective mechanical ventilation by using low tidal volume ventilation and driving pressure may decrease pulmonary complications and improve survival. Low level of positive end-expiratory pressure (PEEP) can be initiated and titrated with careful cardiac output and respiratory mechanics monitoring. Furthermore, optimizing gas exchange by avoiding hypoxia and hyperoxia as well as maintaining normocarbia may improve neurological and survival outcome. Early multidisciplinary cardiac rehabilitation intervention is recommended. Minimally invasive monitoring techniques, that is, echocardiography, transpulmonary thermodilution method measuring extravascular lung water, as well as transcranial Doppler ultrasound, might be useful to improve appropriate management of post-cardiac arrest patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cardiac Remodeling in Response to 1 Year of Intensive Endurance Training

PubMed Central

Arbab-Zadeh, Armin; Perhonen, Merja; Howden, Erin; Peshock, Ronald M.; Zhang, Rong; Adams-Huet, Beverly; Haykowsky, Mark J.; Levine, Benjamin D.

2017-01-01

Background It is unclear whether, and to what extent, the striking cardiac morphological manifestations of endurance athletes are a result of exercise training or a genetically determined characteristic of talented athletes. We hypothesized that prolonged and intensive endurance training in previously sedentary healthy young individuals could induce cardiac remodeling similar to that observed cross-sectionally in elite endurance athletes. Methods and Results Twelve previously sedentary subjects (aged 29±6 years; 7 men and 5 women) trained progressively and intensively for 12 months such that they could compete in a marathon. Magnetic resonance images for assessment of right and left ventricular mass and volumes were obtained at baseline and after 3, 6, 9, and 12 months of training. Maximum oxygen uptake (V̇o2 max) and cardiac output at rest and during exercise (C2H2 rebreathing) were measured at the same time periods. Pulmonary artery catheterization was performed before and after 1 year of training, and pressure-volume and Starling curves were constructed during decreases (lower body negative pressure) and increases (saline infusion) in cardiac volume. Mean V̇o2 max rose from 40.3±1.6 to 48.7±2.5 mL/kg per minute after 1 year (P<0.00001), associated with an increase in both maximal cardiac output and stroke volume. Left and right ventricular mass increased progressively with training duration and intensity and reached levels similar to those observed in elite endurance athletes. In contrast, left ventricular volume did not change significantly until 6 months of training, although right ventricular volume increased progressively from the outset; Starling and pressure-volume curves approached but did not match those of elite athletes. Conclusions One year of prolonged and intensive endurance training leads to cardiac morphological adaptations in previously sedentary young subjects similar to those observed in elite endurance athletes; however, it is not

Evidence for increased cardiac compliance during exposure to simulated microgravity

NASA Technical Reports Server (NTRS)

Koenig, S. C.; Convertino, V. A.; Fanton, J. W.; Reister, C. A.; Gaffney, F. A.; Ludwig, D. A.; Krotov, V. P.; Trambovetsky, E. V.; Latham, R. D.

1998-01-01

We measured hemodynamic responses during 4 days of head-down tilt (HDT) and during graded lower body negative pressure (LBNP) in invasively instrumented rhesus monkeys to test the hypotheses that exposure to simulated microgravity increases cardiac compliance and that decreased stroke volume, cardiac output, and orthostatic tolerance are associated with reduced left ventricular peak dP/dt. Six monkeys underwent two 4-day (96 h) experimental conditions separated by 9 days of ambulatory activities in a crossover counterbalance design: 1) continuous exposure to 10 degrees HDT and 2) approximately 12-14 h per day of 80 degrees head-up tilt and 10-12 h supine (control condition). Each animal underwent measurements of central venous pressure (CVP), left ventricular and aortic pressures, stroke volume, esophageal pressure (EsP), plasma volume, alpha1- and beta1-adrenergic responsiveness, and tolerance to LBNP. HDT induced a hypovolemic and hypoadrenergic state with reduced LBNP tolerance compared with the control condition. Decreased LBNP tolerance with HDT was associated with reduced stroke volume, cardiac output, and peak dP/dt. Compared with the control condition, a 34% reduction in CVP (P = 0.010) and no change in left ventricular end-diastolic area during HDT was associated with increased ventricular compliance (P = 0.0053). Increased cardiac compliance could not be explained by reduced intrathoracic pressure since EsP was unaltered by HDT. Our data provide the first direct evidence that increased cardiac compliance was associated with headward fluid shifts similar to those induced by exposure to spaceflight and that reduced orthostatic tolerance was associated with lower cardiac contractility.

Cardiac Patients’ Walking Activity Determined by a Step Counter in Cardiac Telerehabilitation: Data From the Intervention Arm of a Randomized Controlled Trial

PubMed Central

Hansen, John; Grønkjær, Mette; Andreasen, Jan Jesper; Nielsen, Gitte; Sørensen, Erik Elgaard; Dinesen, Birthe Irene

2016-01-01

Background Walking represents a large part of daily physical activity. It reduces both overall and cardiovascular diseases and mortality and is suitable for cardiac patients. A step counter measures walking activity and might be a motivational tool to increase and maintain physical activity. There is a lack of knowledge about both cardiac patients’ adherence to step counter use in a cardiac telerehabilitation program and how many steps cardiac patients walk up to 1 year after a cardiac event. Objective The purpose of this substudy was to explore cardiac patients’ walking activity. The walking activity was analyzed in relation to duration of pedometer use to determine correlations between walking activity, demographics, and medical and rehabilitation data. Methods A total of 64 patients from a randomized controlled telerehabilitation trial (Teledi@log) from Aalborg University Hospital and Hjoerring Hospital, Denmark, from December 2012 to March 2014 were included in this study. Inclusion criteria were patients hospitalized with acute coronary syndrome, heart failure, and coronary artery bypass grafting or valve surgery. In Teledi@log, the patients received telerehabilitation technology and selected one of three telerehabilitation settings: a call center, a community health care center, or a hospital. Monitoring of steps continued for 12 months and a step counter (Fitbit Zip) was used to monitor daily steps. Results Cardiac patients walked a mean 5899 (SD 3274) steps per day, increasing from mean 5191 (SD 3198) steps per day in the first week to mean 7890 (SD 2629) steps per day after 1 year. Adherence to step counter use lasted for a mean 160 (SD 100) days. The patients who walked significantly more were younger (P=.01) and continued to use the pedometer for a longer period (P=.04). Furthermore, less physically active patients weighed more. There were no significant differences in mean steps per day for patients in the three rehabilitation settings or in the

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

Continuous cardiac output measurement - Aspects of Doppler frequency analysis

NASA Technical Reports Server (NTRS)

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

1975-01-01

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.

Comparison of Minimally and More Invasive Methods of Determining Mixed Venous Oxygen Saturation.

PubMed

Smit, Marli; Levin, Andrew I; Coetzee, Johan F

2016-04-01

To investigate the accuracy of a minimally invasive, 2-step, lookup method for determining mixed venous oxygen saturation compared with conventional techniques. Single-center, prospective, nonrandomized, pilot study. Tertiary care hospital, university setting. Thirteen elective cardiac and vascular surgery patients. All participants received intra-arterial and pulmonary artery catheters. Minimally invasive oxygen consumption and cardiac output were measured using a metabolic module and lithium-calibrated arterial waveform analysis (LiDCO; LiDCO, London), respectively. For the minimally invasive method, Step 1 involved these minimally invasive measurements, and arterial oxygen content was entered into the Fick equation to calculate mixed venous oxygen content. Step 2 used an oxyhemoglobin curve spreadsheet to look up mixed venous oxygen saturation from the calculated mixed venous oxygen content. The conventional "invasive" technique used pulmonary artery intermittent thermodilution cardiac output, direct sampling of mixed venous and arterial blood, and the "reverse-Fick" method of calculating oxygen consumption. LiDCO overestimated thermodilution cardiac output by 26%. Pulmonary artery catheter-derived oxygen consumption underestimated metabolic module measurements by 27%. Mixed venous oxygen saturation differed between techniques; the calculated values underestimated the direct measurements by between 12% to 26.3%, this difference being statistically significant. The magnitude of the differences between the minimally invasive and invasive techniques was too great for the former to act as a surrogate of the latter and could adversely affect clinical decision making. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization of Glutamatergic Neurons in the Rat Atrial Intrinsic Cardiac Ganglia that Project to the Cardiac Ventricular Wall

PubMed Central

Wang, Ting; Miller, Kenneth E.

2016-01-01

The intrinsic cardiac nervous system modulates cardiac function by acting as an integration site for regulating autonomic efferent cardiac output. This intrinsic system is proposed to be composed of a short cardio-cardiac feedback control loop within the cardiac innervation hierarchy. For example, electrophysiological studies have postulated the presence of sensory neurons in intrinsic cardiac ganglia for regional cardiac control. There is still a knowledge gap, however, about the anatomical location and neurochemical phenotype of sensory neurons inside intrinsic cardiac ganglia. In the present study, rat intrinsic cardiac ganglia neurons were characterized neurochemically with immunohistochemistry using glutamatergic markers: vesicular glutamate transporters 1 and 2 (VGLUT1; VGLUT2), and glutaminase (GLS), the enzyme essential for glutamate production. Glutamatergic neurons (VGLUT1/VGLUT2/GLS) in the ICG that have axons to the ventricles were identified by retrograde tracing of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected in the ventricular wall. Co-labeling of VGLUT1, VGLUT2, and GLS with the vesicular acetylcholine transporter (VAChT) was used to evaluate the relationship between post-ganglionic autonomic neurons and glutamatergic neurons. Sequential labeling of VGLUT1 and VGLUT2 in adjacent tissue sections was used to evaluate the co-localization of VGLUT1 and VGLUT2 in ICG neurons. Our studies yielded the following results: (1) intrinsic cardiac ganglia contain glutamatergic neurons with GLS for glutamate production and VGLUT1 and 2 for transport of glutamate into synaptic vesicles; (2) atrial intrinsic cardiac ganglia contain neurons that project to ventricle walls and these neurons are glutamatergic; (3) many glutamatergic ICG neurons also were cholinergic, expressing VAChT. (4) VGLUT1 and VGLUT2 co-localization occurred in ICG neurons with variation of their protein expression level. Investigation of both glutamatergic and cholinergic ICG

Cardiac function and exercise adaptation in 8 children with LPIN1 mutations.

PubMed

Legendre, Antoine; Khraiche, Diala; Ou, Phalla; Mauvais, François-Xavier; Madrange, Marine; Guemann, Anne-Sophie; Jais, Jean-Philippe; Bonnet, Damien; Hamel, Yamina; de Lonlay, Pascale

2018-03-01

Lipin-1 deficiency is a major cause of rhabdomyolysis that are precipitated by febrile illness. The prognosis is poor, with one-third of patients dying from cardiac arrest during a crisis episode. Apart from acute rhabdomyolysis, most patients are healthy, showing normal clinical and cardiac ultrasound parameters. We report cardiac and exercise examinations of 8 children carrying two LPIN1 mutations. The examinations were performed outside of a myolysis episode, but one patient presented with fever during one examination. All but one patient displayed normal resting cardiac function, as determined by echocardiography. One patient exhibited slight left ventricular dysfunction at rest and a lack of increased stroke volume during cycle ramp exercise. During exercise, peripheral muscle adaptation was impaired in 2 patients compared to healthy controls: they presented an abnormal increase in cardiac output relative to oxygen uptake: dQ/dVO 2 =8.2 and 9.5 (>2DS of controls population). One patient underwent 2 exercise tests; during one test, the patient was febrile, leading to acute rhabdomyolysis in the following hours. He exhibited changes in recovery muscle reoxygenation parameters and an increased dQ/dVO 2 during exercise compared with that under normothermia (7.9 vs 6), which did not lead to acute rhabdomyolysis. The four patients assessed by cardiac 1 H-magnetic resonance spectroscopy exhibited signs of intracardiac steatosis. We observed abnormal haemodynamic profiles during exercise in 3/8 patients with lipin-1 deficiency, suggesting impaired muscle oxidative phosphorylation during exercise. Fever appeared to be an aggravating factor. One patient exhibited moderate cardiac dysfunction, which was possibly related to intracardiac stored lipid toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

Temperature effects on aerobic scope and cardiac performance of European perch (Perca fluviatilis).

PubMed

Jensen, Denise Lyager; Overgaard, Johannes; Wang, Tobias; Gesser, Hans; Malte, Hans

2017-08-01

Several recent studies have highlighted how impaired cardiac performance at high temperatures and in hypoxia may compromise the capacity for oxygen transport. Thus, at high temperatures impaired cardiac capacity is proposed to reduce oxygen transport to a degree that lowers aerobic scope and compromises thermal tolerance (the oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis). To investigate this hypothesis, we measured aerobic and cardiac performance of a eurythermal freshwater teleost, the European perch (Perca fluviatilis). Rates of oxygen consumption were measured during rest and activity at temperatures between 5°C and 27°C, and we evaluated cardiac function by in vivo measurements of heart rate and in vitro studies to determine contractility of myocardial strips. Aerobic scope increased progressively from 5°C to 21°C, after which it levelled off. Heart rate showed a similar response. We found little difference between resting and active heart rate at high temperature suggesting that increased cardiac scope during activity is primarily related to changes in stroke volume. To examine the effects of temperature on cardiac capacity, we measured isometric force development in electrically paced myocardial preparations during different combinations of temperature, pacing frequency, oxygenation and adrenergic stimulation. The force-frequency product increased markedly upon adrenergic stimulation at 21 and 27°C (with higher effects at 21°C) and the cardiac preparations were highly sensitive to hypoxia. These findings suggest that at (critically) high temperatures, cardiac output may diminish due to a decreased effect of adrenergic stimulation and that this effect may be further exacerbated if the heart becomes hypoxic. Hence cardiac limitations may contribute to the inability to increase aerobic scope at high temperatures in the European perch (Perca fluviatilis). Copyright © 2017 Elsevier Ltd. All rights reserved.

Arg16/Gly beta2-adrenergic receptor polymorphism alters the cardiac output response to isometric exercise.

PubMed

Eisenach, John H; Barnes, Sunni A; Pike, Tasha L; Sokolnicki, Lynn A; Masuki, Shizue; Dietz, Niki M; Rehfeldt, Kent H; Turner, Stephen T; Joyner, Michael J

2005-11-01

Normotensive adults homozygous for glycine (Gly) of the Arg16/Gly beta2-adrenergic-receptor polymorphism have 1) greater forearm beta2-receptor mediated vasodilation and 2) a higher heart rate (HR) response to isometric handgrip than arginine (Arg) homozygotes. To test the hypothesis that the higher HR response in Gly16 subjects serves to maintain the pressor response [increased cardiac output (CO)] in the setting of augmented peripheral vasodilation to endogenous catecholamines, we measured continuous HR (ECG), arterial pressure (Finapres), and CO (transthoracic echocardiography) during isometric, 40% submaximal handgrip to fatigue in healthy subjects homozygous for Gly (n = 30; mean age +/- SE: 30 +/- 1.2, 13 women) and Arg (n = 17, age 30 +/- 1.6, 11 women). Resting data were similar between groups. Handgrip produced similar increases in arterial pressure and venous norepinephrine and epinephrine concentrations; however, HR increased more in the Gly group (60.1 +/- 4.3% increase from baseline vs. 45.5 +/- 3.9%, P = 0.03), and this caused CO to be higher (Gly: 7.6 +/- 0.3 l/m vs. Arg: 6.5 +/- 0.3 l/m, P = 0.03), whereas the decrease in systemic vascular resistance in the Gly group did not reach significance (P = 0.09). We conclude that Gly16 homozygotes generate a higher CO to maintain the pressor response to handgrip. The influence of polymorphic variants in the beta2-adrenergic receptor gene on the cardiovascular response to sympathoexcitation may have important implications in the development of hypertension and heart failure.

Influence of gravity on cardiac performance.

PubMed

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

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.

Cardiac effects of MDMA on the metabolic profile determined with 1H-magnetic resonance spectroscopy in the rat†

PubMed Central

Perrine, Shane A.; Michaels, Mark S.; Ghoddoussi, Farhad; Hyde, Elisabeth M.; Tancer, Manuel E.; Galloway, Matthew P.

2010-01-01

Despite the potential for deleterious (even fatal) effects on cardiac physiology, 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) abuse abounds driven mainly by its euphoric effects. Acute exposure to MDMA has profound cardiovascular effects on blood pressure and heart rate in humans and animals. To determine the effects of MDMA on cardiac metabolites in rats, MDMA (0, 5, or 10 mg/kg) was injected every 2 h for a total of four injections; animals were sacrificed 2 h after the last injection (8 h drug exposure), and their hearts removed and tissue samples from left ventricular wall dissected. High resolution magic angle spinning proton magnetic resonance spectroscopy (1H-MRS) at 11.7 T, a specialized version of MRS aptly suited for analysis of semi-solid materials such as intact tissue samples, was used to measure the cardiac metabolomic profile, including alanine, lactate, succinate, creatine, and carnitine, in heart tissue from rats treated with MDMA. MDMA effects on MR-visible choline, glutamate, glutamine, and taurine were also determined. Body temperature was measured following each MDMA administration and serotonin and norepinephrine (NE) levels were measured by high pressure liquid chromatography (HPLC) in heart tissue from treated animals. MDMA significantly and dose-dependently increased body temperature, a hallmark of amphetamines. Serotonin, but not NE, levels were significantly and dose-dependently decreased by MDMA in the heart wall. MDMA significantly altered the MR-visible profile with an increase in carnitine and no change in other key compounds involved in cardiomyocyte energy metabolomics. Finally, choline levels were significantly decreased by MDMA in heart. The results are consistent with the notion that MDMA has significant effects on cardiovascular serotonergic tone and disrupts the metabolic homeostasis of energy regulation in cardiac tissue, potentially increasing utilization of fatty acid metabolism. The contributions of serotonergic

Cardiac effects of MDMA on the metabolic profile determined with 1H-magnetic resonance spectroscopy in the rat.

PubMed

Perrine, Shane A; Michaels, Mark S; Ghoddoussi, Farhad; Hyde, Elisabeth M; Tancer, Manuel E; Galloway, Matthew P

2009-05-01

Despite the potential for deleterious (even fatal) effects on cardiac physiology, 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) abuse abounds driven mainly by its euphoric effects. Acute exposure to MDMA has profound cardiovascular effects on blood pressure and heart rate in humans and animals. To determine the effects of MDMA on cardiac metabolites in rats, MDMA (0, 5, or 10 mg/kg) was injected every 2 h for a total of four injections; animals were sacrificed 2 h after the last injection (8 h drug exposure), and their hearts removed and tissue samples from left ventricular wall dissected. High resolution magic angle spinning proton magnetic resonance spectroscopy ((1)H-MRS) at 11.7 T, a specialized version of MRS aptly suited for analysis of semi-solid materials such as intact tissue samples, was used to measure the cardiac metabolomic profile, including alanine, lactate, succinate, creatine, and carnitine, in heart tissue from rats treated with MDMA. MDMA effects on MR-visible choline, glutamate, glutamine, and taurine were also determined. Body temperature was measured following each MDMA administration and serotonin and norepinephrine (NE) levels were measured by high pressure liquid chromatography (HPLC) in heart tissue from treated animals. MDMA significantly and dose-dependently increased body temperature, a hallmark of amphetamines. Serotonin, but not NE, levels were significantly and dose-dependently decreased by MDMA in the heart wall. MDMA significantly altered the MR-visible profile with an increase in carnitine and no change in other key compounds involved in cardiomyocyte energy metabolomics. Finally, choline levels were significantly decreased by MDMA in heart. The results are consistent with the notion that MDMA has significant effects on cardiovascular serotonergic tone and disrupts the metabolic homeostasis of energy regulation in cardiac tissue, potentially increasing utilization of fatty acid metabolism. The contributions of serotonergic

Cardiac structure and function in the obese: a cardiovascular magnetic resonance imaging study.

PubMed

Danias, Peter G; Tritos, Nicholas A; Stuber, Matthias; Kissinger, Kraig V; Salton, Carol J; Manning, Warren J

2003-07-01

Obesity is a major health problem in the Western world. Among obese subjects cardiac pathology is common, but conventional noninvasive imaging modalities are often suboptimal for detailed evaluation of cardiac structure and function. We investigated whether cardiovascular magnetic resonance imaging (CMR) can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. In this prospective cross-sectional study, CMR was used to quantify left and right ventricular volumes, ejection fraction, mass, cardiac output, and apical left ventricular rotation in 25 clinically healthy obese men and 25 age-matched lean controls. Obese subjects had higher left ventricular mass (203 +/- 38 g vs. 163 +/- 22 g, p < 0.001), end-diastolic volume (176 +/- 29 mL vs. 156 +/- 25 mL, p < 0.05), and cardiac output (8.2 +/- 1.2 L/min vs. 6.4 +/- 1.3 L/min, p < 0.001). The obese also had increased right ventricular mass (105 +/- 25 g vs. 87 +/- 18 g, p < 0.005) and end-diastolic volume (179 +/- 36 mL vs. 155 +/- 28 mL, p < 0.05). When indexed for height, differences in left and right ventricular mass, and left ventricular end-diastolic volume remained significant. Apical left ventricular rotation and rotational velocity patterns were also different between obese and lean subjects. Obesity is independently associated with remodeling of the heart. Cardiovascular magnetic resonance imaging identifies subtle cardiac abnormalities and may be the preferred imaging technique to evaluate cardiac structure and function in the obese.

Acupuncture Effects on Cardiac Functions Measured by Cardiac Magnetic Resonance Imaging in a Feline Model

PubMed Central

Lin, Jen-Hsou; Shih, Chen-Haw; Kaphle, Krishna; Wu, Leang-Shin; Tseng, Weng-Yih; Chiu, Jen-Hwey; Lee, Tzu-chi

2010-01-01

The usefulness of acupuncture (AP) as a complementary and/or alternative therapy in animals is well established but more research is needed on its clinical efficacy relative to conventional therapy, and on the underlying mechanisms of the effects of AP. Cardiac magnetic resonance imaging (CMRI), an important tool in monitoring cardiovascular diseases, provides a reliable method to monitor the effects of AP on the cardiovascular system. This controlled experiment monitored the effect electro-acupuncture (EA) at bilateral acupoint Neiguan (PC6) on recovery time after ketamine/xylazine cocktail anesthesia in healthy cats. The CMRI data established the basic feline cardiac function index (CFI), including cardiac output and major vessel velocity. To evaluate the effect of EA on the functions of the autonomic nervous and cardiovascular systems, heart rate, respiration rate, electrocardiogram and pulse rate were also measured. Ketamine/xylazine cocktail anesthesia caused a transient hypertension in the cats; EA inhibited this anesthetic-induced hypertension and shortened the post-anesthesia recovery time. Our data support existing knowledge on the cardiovascular benefits of EA at PC6, and also provide strong evidence for the combination of anesthesia and EA to shorten post-anesthesia recovery time and counter the negative effects of anesthetics on cardiac physiology. PMID:18955311

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

PubMed

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

2007-11-01

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.

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

PubMed

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

2015-02-01

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.

A Novel Idea to Improve Cardiac Output of Mechanical Circulatory Support Devices by Optimizing Kinetic Energy Transfer Available in Forward Moving Aortic Blood Flow.

PubMed

Qureshi, Muhammad B; Glower, Jacob; Ewert, Daniel L; Koenig, Steven C

2017-06-01

Mechanical circulatory support devices (MCSDs) have gained widespread clinical acceptance as an effective heart failure (HF) therapy. The concept of harnessing the kinetic energy (KE) available in the forward aortic flow (AOF) is proposed as a novel control strategy to further increase the cardiac output (CO) provided by MCSDs. A complete mathematical development of the proposed theory and its application to an example MCSDs (two-segment extra-aortic cuff) are presented. To achieve improved device performance and physiologic benefit, the example MCSD timing is regulated to maximize the forward AOF KE and minimize retrograde flow. The proof-of-concept was tested to provide support with and without KE control in a computational HF model over a wide range of HF test conditions. The simulation predicted increased stroke volume (SV) by 20% (9 mL), CO by 23% (0.50 L/min), left ventricle ejection fraction (LVEF) by 23%, and diastolic coronary artery flow (CAF) by 55% (3 mL) in severe HF at a heart rate (HR) of 60 beats per minute (BPM) during counterpulsation (CP) support with KE control. The proposed KE control concept may improve performance of other MCSDs to further enhance their potential clinical benefits, which warrants further investigation. The next step is to investigate various assist technologies and determine where this concept is best applied. Then bench-test the combination of kinetic energy optimization and its associated technology choice and finally test the combination in animals.

Use of transesophageal Doppler ultrasonography in ventilated pediatric patients: derivation of cardiac output.

PubMed

Tibby, S M; Hatherill, M; Murdoch, I A

2000-06-01

To ascertain if cardiac output (CO) could be derived from blood flow velocity measured in the descending aorta of ventilated children by transesophageal Doppler ultrasonography (TED) without the need for direct aortic cross sectional area measurement, and to evaluate the ability of TED to follow changes in CO when compared with femoral artery thermodilution. Prospective, comparison study. A 16-bed pediatric intensive care unit of a university hospital. A total of 100 ventilated infants and children aged 4 days to 18 yrs (median age, 27 months). Diagnoses included postcardiac surgery (n = 58), sepsis/multiple organ failure (n = 32), respiratory disease (n = 5), and other (n = 5). A total of 55 patients were receiving inotropes or vasodilators. When patients were hemodynamically stable, a TED probe was placed into the distal esophagus to obtain optimal signal, and minute distance (MD) was recorded. Five consecutive MD measurements were made concurrently with five femoral artery thermodilution measurements, and the concurrent measurements were averaged. CO was then manipulated by fluid administration or inotrope adjustment, and the readings were repeated. Femoral artery thermodilution CO ranged from 0.32 to 9.19 L/min, (median, 2.46 L/min), and encompassed a wide range of high and low flow states. Theoretical consideration revealed the optimal TED estimate for CO to be (MD x patient height2 x 10(-7)). Linear regression analysis yielded a power function model such that: estimated CO = 1.158 x (MD x height2 x 10(-7))(0.785), r2 = 0.879, standard error of the estimate = 0.266. Inclusion of a correction factor for potential changes in aortic cross-sectional area with hypo- and hypertension did not appreciably improve the predictive value of the model. MD was able to follow percentage changes in CO, giving a mean bias of 0.87% (95% confidence interval -0.85% to 2.59%), and limits of agreement of +/- 16.82%. The median coefficient of variation for MD was 3.3%. TED provides

Cardiac troponin T determination by a highly sensitive assay in postmortem serum and pericardial fluid.

PubMed

González-Herrera, Lucas; Valenzuela, Aurora; Ramos, Valentín; Blázquez, Antonia; Villanueva, Enrique

2016-06-01

The main objective of this study was to test, for the first time, a highly sensitive cardiac troponin T (cTnThs) assay in postmortem serum and pericardial fluid and to evaluate cardiac troponin T (cTnT) levels and their stability after death at different postmortem intervals, in an attempt to determine the viability of the cTnThs assay in the postmortem diagnosis of the cause of death. cTnT levels were determined in serum and pericardial fluid samples taken from 58 cadavers at known postmortem intervals, whose causes of death were categorized into the following groups: (1) sudden cardiac deaths, (2) multiple trauma, (3) mechanical asphyxia, and (4) other natural deaths. cTnT was determined by inmunoassay, using the Troponin T highly sensitive STAT assay (Roche(®)). Average cTnT levels measured by a highly sensitive assay in postmortem serum were markedly higher than clinical serum levels. Moreover, similar results, higher cTnT levels in postmortem pericardial fluid, were obtained when compared to levels found in pericardial fluid taken from two living patients during coronary artery bypass surgery. cTnT levels in both postmortem fluids remained stable for up to 34 h after death. No differences in cTnT levels in either postmortem fluid by sex and age were detected. Levels of cTnT found in pericardial fluid in the other natural deaths group were significantly lower than the cTnT levels found in that postmortem fluid from any of the other causes of death groups. It is therefore reasonable to conclude that determination of cTnT by a highly sensitive assay in pericardial fluid can provide forensic pathologists with a complementary test to the diagnosis of cause of death.

Single cardiac ventricular myosins are autonomous motors

PubMed Central

Wang, Yihua; Yuan, Chen-Ching; Kazmierczak, Katarzyna; Szczesna-Cordary, Danuta

2018-01-01

Myosin transduces ATP free energy into mechanical work in muscle. Cardiac muscle has dynamically wide-ranging power demands on the motor as the muscle changes modes in a heartbeat from relaxation, via auxotonic shortening, to isometric contraction. The cardiac power output modulation mechanism is explored in vitro by assessing single cardiac myosin step-size selection versus load. Transgenic mice express human ventricular essential light chain (ELC) in wild- type (WT), or hypertrophic cardiomyopathy-linked mutant forms, A57G or E143K, in a background of mouse α-cardiac myosin heavy chain. Ensemble motility and single myosin mechanical characteristics are consistent with an A57G that impairs ELC N-terminus actin binding and an E143K that impairs lever-arm stability, while both species down-shift average step-size with increasing load. Cardiac myosin in vivo down-shifts velocity/force ratio with increasing load by changed unitary step-size selections. Here, the loaded in vitro single myosin assay indicates quantitative complementarity with the in vivo mechanism. Both have two embedded regulatory transitions, one inhibiting ADP release and a second novel mechanism inhibiting actin detachment via strain on the actin-bound ELC N-terminus. Competing regulators filter unitary step-size selection to control force-velocity modulation without myosin integration into muscle. Cardiac myosin is muscle in a molecule. PMID:29669825

Plant-derived cardiac glycosides: Role in heart ailments and cancer management.

PubMed

Patel, Seema

2016-12-01

Cardiac glycosides, the cardiotonic steroids such as digitalis have been in use as heart ailment remedy since ages. They manipulate the renin-angiotensin axis to improve cardiac output. However; their safety and efficacy have come under scrutiny in recent times, as poisoning and accidental mortalities have been observed. In order to better understand and exploit them as cardiac ionotropes, studies are being pursued using different cardiac glycosides such as digitoxin, digoxin, ouabain, oleandrin etc. Several cardiac glycosides as peruvoside have shown promise in cancer control, especially ovary cancer and leukemia. Functional variability of these glycosides has revealed that not all cardiac glycosides are alike. Apart from their specific affinity to sodium-potassium ATPase, their therapeutic dosage and behavior in poly-morbidity conditions needs to be considered. This review presents a concise account of the key findings in recent years with adequate elaboration of the mechanisms. This compilation is expected to contribute towards management of cardiac, cancer, even viral ailments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

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

NASA Technical Reports Server (NTRS)

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

1992-01-01

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.

Sudden cardiac arrest as a rare presentation of myxedema coma: case report.

PubMed

Salhan, Divya; Sapkota, Deepak; Verma, Prakash; Kandel, Saroj; Abdulfattah, Omar; Lixon, Antony; Zwenge, Deribe; Schmidt, Frances

2017-01-01

Myxedema coma is a decompensated hypothyroidism which occurs due to long-standing, undiagnosed, or untreated hypothyroidism. Untreated hypothyroidism is known to affect almost all organs including the heart. It is associated with a decrease in cardiac output, stroke volume due to decreased myocardial contractility, and an increase in systemic vascular resistance. It can cause cardiac arrhythmias and the most commonly seen conduction abnormalities are sinus bradycardia, heart block, ventricular tachycardia, and torsade de pointes. The authors report a case of an elderly man who presented with sudden cardiac arrest and myxedema coma and who was successfully revived.

Prototype development of an electrical impedance based simultaneous respiratory and cardiac monitoring system for gated radiotherapy.

PubMed

Kohli, Kirpal; Liu, Jeff; Schellenberg, Devin; Karvat, Anand; Parameswaran, Ash; Grewal, Parvind; Thomas, Steven

2014-10-14

In radiotherapy, temporary translocations of the internal organs and tumor induced by respiratory and cardiac activities can undesirably lead to significantly lower radiation dose on the targeted tumor but more harmful radiation on surrounding healthy tissues. Respiratory and cardiac gated radiotherapy offers a potential solution for the treatment of tumors located in the upper thorax. The present study focuses on the design and development of simultaneous acquisition of respiratory and cardiac signal using electrical impedance technology for use in dual gated radiotherapy. An electronic circuitry was developed for monitoring the bio-impedance change due to respiratory and cardiac motions and extracting the cardiogenic ECG signal. The system was analyzed in terms of reliability of signal acquisition, time delay, and functionality in a high energy radiation environment. The resulting signal of the system developed was also compared with the output of the commercially available Real-time Position Management™ (RPM) system in both time and frequency domains. The results demonstrate that the bioimpedance-based method can potentially provide reliable tracking of respiratory and cardiac motion in humans, alternative to currently available methods. When compared with the RPM system, the impedance-based system developed in the present study shows similar output pattern but different sensitivities in monitoring different respiratory rates. The tracking of cardiac motion was more susceptible to interference from other sources than respiratory motion but also provided synchronous output compared with the ECG signal extracted. The proposed hardware-based implementation was observed to have a worst-case time delay of approximately 33 ms for respiratory monitoring and 45 ms for cardiac monitoring. No significant effect on the functionality of the system was observed when it was tested in a radiation environment with the electrode lead wires directly exposed to high-energy X

Coi-wiz: An interactive computer wizard for analyzing cardiac optical signals.

PubMed

Yuan, Xiaojing; Uyanik, Ilyas; Situ, Ning; Xi, Yutao; Cheng, Jie

2009-01-01

A number of revolutionary techniques have been developed for cardiac electrophysiology research to better study the various arrhythmia mechanisms that can enhance ablating strategies for cardiac arrhythmias. Once the three-dimensional high resolution cardiac optical imaging data is acquired, it is time consuming to manually go through them and try to identify the patterns associated with various arrhythmia symptoms. In this paper, we present an interactive computer wizard that helps cardiac electrophysiology researchers to visualize and analyze the high resolution cardiac optical imaging data. The wizard provides a file interface that accommodates different file formats. A series of analysis algorithms output waveforms, activation and action potential maps after spatial and temporal filtering, velocity field and heterogeneity measure. The interactive GUI allows the researcher to identify the region of interest in both the spatial and temporal domain, thus enabling them to study different heart chamber at their choice.

Cardiac index is associated with brain aging: the Framingham Heart Study.

PubMed

Jefferson, Angela L; Himali, Jayandra J; Beiser, Alexa S; Au, Rhoda; Massaro, Joseph M; Seshadri, Sudha; Gona, Philimon; Salton, Carol J; DeCarli, Charles; O'Donnell, Christopher J; Benjamin, Emelia J; Wolf, Philip A; Manning, Warren J

2010-08-17

Cardiac dysfunction is associated with neuroanatomic and neuropsychological changes in aging adults with prevalent cardiovascular disease, theoretically because systemic hypoperfusion disrupts cerebral perfusion, contributing to subclinical brain injury. We hypothesized that cardiac function, as measured by cardiac index, would be associated with preclinical brain magnetic resonance imaging (MRI) and neuropsychological markers of ischemia and Alzheimer disease in the community. Brain MRI, cardiac MRI, neuropsychological, and laboratory data were collected on 1504 Framingham Offspring Cohort participants free of clinical stroke, transient ischemic attack, or dementia (age, 61+/-9 years; 54% women). Neuropsychological and brain MRI variables were related to cardiac MRI-assessed cardiac index (cardiac output/body surface area). In multivariable-adjusted models, cardiac index was positively related to total brain volume (P=0.03) and information processing speed (P=0.02) and inversely related to lateral ventricular volume (P=0.048). When participants with clinically prevalent cardiovascular disease were excluded, the relation between cardiac index and total brain volume remained (P=0.02). Post hoc comparisons revealed that participants in the bottom cardiac index tertile (values <2.54) and middle cardiac index tertile (values between 2.54 and 2.92) had significantly lower brain volumes (P=0.04) than participants in the top cardiac index tertile (values >2.92). Although observational data cannot establish causality, our findings are consistent with the hypothesis that decreasing cardiac function, even at normal cardiac index levels, is associated with accelerated brain aging.

Cardiac index is associated with brain aging: The Framingham Heart Study

PubMed Central

Jefferson, Angela L.; Himali, Jayandra J.; Beiser, Alexa S.; Au, Rhoda; Massaro, Joseph M.; Seshadri, Sudha; Gona, Philimon; Salton, Carol J.; DeCarli, Charles; O’Donnell, Christopher J.; Benjamin, Emelia J.; Wolf, Philip A.; Manning, Warren J.

2010-01-01

Background Cardiac dysfunction is associated with neuroanatomic and neuropsychological changes in aging adults with prevalent cardiovascular disease (CVD), theoretically because systemic hypoperfusion disrupts cerebral perfusion, contributing to subclinical brain injury. We hypothesized that cardiac function, as measured by cardiac index, would be associated with pre-clinical brain magnetic resonance imaging (MRI) and neuropsychological markers of ischemia and Alzheimer’s disease in the community. Methods and Results Brain MRI, cardiac MRI, neuropsychological, and laboratory data were collected on 1504 Framingham Offspring Cohort participants free from clinical stroke, transient ischemic attack, or dementia (61±9 years; 54% women). Neuropsychological and brain MRI variables were related to cardiac MRI-assessed cardiac index (cardiac output/body surface area). In multivariable-adjusted models, cardiac index was positively related to total brain volume (P=0.03) and information processing speed (P=0.02) and inversely related to lateral ventricular volume (P=0.048). When participants with clinically prevalent CVD were excluded, the relation between cardiac index and total brain volume remained (P=0.02). Post-hoc comparisons revealed that participants in the bottom cardiac index tertile (values<2.54) and middle cardiac index tertile (values between 2.54 and 2.92) had significantly lower brain volumes (P=0.04) than participants in the top cardiac index tertile (values>2.92). Conclusions Although observational data cannot establish causality, our findings are consistent with the hypothesis that decreasing cardiac function, even at normal cardiac index levels, is associated with accelerated brain aging. PMID:20679552

Early 4-week cardiac rehabilitation exercise training in elderly patients after heart surgery.

PubMed

Eder, Barbara; Hofmann, Peter; von Duvillard, Serge P; Brandt, Dieter; Schmid, Jean-Paul; Pokan, Rochus; Wonisch, Manfred

2010-01-01

The aim of this study was to assess the effects on exercise performance of supplementing a standard cardiac rehabilitation program with additional exercise programming compared to the standard cardiac rehabilitation program alone in elderly patients after heart surgery. In this prospective, randomized controlled trial, 60 patients (32 men and 28 women, mean age 73.1 +/- 4.7 years) completed cardiac rehabilitation (initiated 12.2 +/- 4.9 days postsurgery). Subjects were assigned to either a control group (CG, standard cardiac rehabilitation program [n = 19]), or an intervention group (IG, additional walking [n = 19], or cycle ergometry training [n = 22]). A symptom limited cardiopulmonary exercise test and 6-minute walk test (6MWT) were performed before and after 4 weeks of cardiac rehabilitation. The MacNew questionnaire was used to assess quality of life (QOL). At baseline, no significant differences for peak oxygen uptake ((.)VO2), maximal power output, or the 6MWT were detected between IG and CG. Global QOL was significantly higher in IG. After 4 weeks of cardiac rehabilitation, patients significantly improved in absolute values of the cardiopulmonary exercise test, 6MWT, and QOL scores. Significant differences between groups were found for peak (.)VO2 (IG: 18.2 +/- 3.1 mL x kg x min vs. CG: 16.5 +/- 2.2 mL x kg x min, P < .05); maximal power output (IG: 72.2 +/- 16 W vs. CG: 60.7 +/- 15 W, P < .05); 6MWT (IG: 454.8 +/- 76.3 m vs. CG: 400.5 +/- 75.5 m, P < .05); and QOL global (IG: 6.5 +/- 0.5 vs. CG: 6.3 +/- 0.6, P < .05). The supplementation of additional walking or cycle exercise training to standard cardiac rehabilitation programming compared to standard cardiac rehabilitation alone in elderly patients after heart surgery leads to significantly better exercise tolerance.

Effects of testosterone and nandrolone on cardiac function: a randomized, placebo-controlled study.

PubMed

Chung, T; Kelleher, S; Liu, P Y; Conway, A J; Kritharides, L; Handelsman, D J

2007-02-01

Androgens have striking effects on skeletal muscle, but the effects on human cardiac muscle function are not well defined, neither has the role of metabolic activation (aromatization, 5alpha reduction) of testosterone on cardiac muscle been directly studied. To assess the effects of testosterone and nandrolone, a non-amplifiable and non-aromatizable pure androgen, on cardiac muscle function in healthy young men. Double-blind, randomized, placebo-controlled, three-arm parallel group clinical trial. Ambulatory care research centre. Healthy young men randomized into three groups of 10 men. Weekly intramuscular injections of testosterone (200 mg mixed esters), nandrolone (200 mg nandrolone decanoate) or matching (2 ml arachis oil vehicle) placebo for 4 weeks. Comprehensive measures of cardiac muscle function involving transthoracic cardiac echocardiography measuring myocardial tissue velocity, peak systolic strain and strain rates, and bioimpedance measurement of cardiac output and systematic vascular resistance. Left ventricular (LV) function (LV ejection fraction, LV modified TEI index), right ventricular (RV) function (ejection area, tricuspid annular systolic planar motion, RV modified TEI index) as well as cardiac afterload (mean arterial pressure, systemic vascular resistance) and overall cardiac contractility (stroke volume, cardiac output) were within age- and gender-specific reference ranges and were not significantly (P < 0.05) altered by either androgen or placebo over 4 weeks of treatment. Minor changes remaining within normal range were observed solely within the testosterone group for: increased LV end-systolic diameter (30 +/- 7 vs. 33 +/- 5 mm, P = 0.04) and RV end-systolic area (12.8 +/- 1.3 vs. 14.6 +/- 3.3 cm(2), P = 0.04), reduced LV diastolic septal velocity (Em, 9.5 +/- 2.6 vs. 8.7 +/- 2.0 cm/s, P = 0.006), increased LV filling pressure (E/Em ratio, 7.1 +/- 1.6 vs. 8.3 +/- 1.8, P = 0.02) and shortened PR interval on the electrocardiogram (167

Cardiac responses to hypoxia and reoxygenation in Drosophila.

PubMed

Zarndt, Rachel; Piloto, Sarah; Powell, Frank L; Haddad, Gabriel G; Bodmer, Rolf; Ocorr, Karen

2015-12-01

An adequate supply of oxygen is important for the survival of all tissues, but it is especially critical for tissues with high-energy demands, such as the heart. Insufficient tissue oxygenation occurs under a variety of conditions, including high altitude, embryonic and fetal development, inflammation, and thrombotic diseases, often affecting multiple organ systems. Responses and adaptations of the heart to hypoxia are of particular relevance in human cardiovascular and pulmonary diseases, in which the effects of hypoxic exposure can range in severity from transient to long-lasting. This study uses the genetic model system Drosophila to investigate cardiac responses to acute (30 min), sustained (18 h), and chronic (3 wk) hypoxia with reoxygenation. Whereas hearts from wild-type flies recovered quickly after acute hypoxia, exposure to sustained or chronic hypoxia significantly compromised heart function upon reoxygenation. Hearts from flies with mutations in sima, the Drosophila homolog of the hypoxia-inducible factor alpha subunit (HIF-α), exhibited exaggerated reductions in cardiac output in response to hypoxia. Heart function in hypoxia-selected flies, selected over many generations for survival in a low-oxygen environment, revealed reduced cardiac output in terms of decreased heart rate and fractional shortening compared with their normoxia controls. Hypoxia-selected flies also had smaller hearts, myofibrillar disorganization, and increased extracellular collagen deposition, consistent with the observed reductions in contractility. This study indicates that longer-duration hypoxic insults exert deleterious effects on heart function that are mediated, in part, by sima and advances Drosophila models for the genetic analysis of cardiac-specific responses to hypoxia and reoxygenation. Copyright © 2015 the American Physiological Society.

Cardiac cycle-synchronized electrical muscle stimulator for lower limb training with the potential to reduce the heart's pumping workload

PubMed Central

Matsuse, Hiroo; Akimoto, Ryuji; Kamiya, Shiro; Moritani, Toshio; Sasaki, Motoki; Ishizaki, Yuta; Ohtsuka, Masanori; Nakayoshi, Takaharu; Ueno, Takafumi; Shiba, Naoto; Fukumoto, Yoshihiro

2017-01-01

Background The lower limb muscle may play an important role in decreasing the heart’s pumping workload. Aging and inactivity cause atrophy and weakness of the muscle, leading to a loss of the heart-assisting role. An electrical lower limb muscle stimulator can prevent atrophy and weakness more effectively than conventional resistance training; however, it has been reported to increase the heart’s pumping workload in some situations. Therefore, more effective tools should be developed. Methods We newly developed a cardiac cycle-synchronized electrical lower limb muscle stimulator by combining a commercially available electrocardiogram monitor and belt electrode skeletal muscle electrical stimulator, making it possible to achieve strong and wide but not painful muscle contractions. Then, we tested the stimulator in 11 healthy volunteers to determine whether the special equipment enabled lower limb muscle training without harming the hemodynamics using plethysmography and a percutaneous cardiac output analyzer. Results In 9 of 11 subjects, the stimulator generated diastolic augmentation waves on the dicrotic notches and end-diastolic pressure reduction waves on the plethysmogram waveforms of the brachial artery, showing analogous waveforms in the intra-aortic balloon pumping heart-assisting therapy. The heart rate, stroke volume, and cardiac output significantly increased during the stimulation. There was no change in the systolic or diastolic blood pressure during the stimulation. Conclusion Cardiac cycle-synchronized electrical muscle stimulation for the lower limbs may enable muscle training without harmfully influencing the hemodynamics and with a potential to reduce the heart’s pumping workload, suggesting a promising tool for effectively treating both locomotor and cardiovascular disorders. PMID:29117189

An ANN-based HRV classifier for cardiac health prognosis.

PubMed

Sunkaria, Ramesh Kumar; Kumar, Vinod; Saxena, Suresh Chandra; Singhal, Achala M

2014-01-01

A multi-layer artificial neural network (ANN)-based heart rate variability (HRV) classifier has been proposed, which gives the cardiac health status as the output based on HRV of the patients independently of the cardiologists' view. The electrocardiogram (ECG) data of 46 patients were recorded in the out-patient department (OPD) of a hospital and HRV was evaluated using self-designed autoregressive-model-based technique. These patients suspected to be suffering from cardiac abnormalities were thoroughly examined by experienced cardiologists. On the basis of symptoms and other investigations, the attending cardiologists advised them to be classified into four categories as per the severity of cardiac health. Out of 46, the HRV data of 28 patients were used for training and data of 18 patients were used for testing of the proposed classifier. The cardiac health classification of each tested patient with the proposed classifier matches with the medical opinion of the cardiologists.

Input-output analysis and the hospital budgeting process.

PubMed Central

Cleverly, W O

1975-01-01

Two hospitals budget systems, a conventional budget and an input-output budget, are compared to determine how they affect management decisions in pricing, output, planning, and cost control. Analysis of data from a 210-bed not-for-profit hospital indicates that adoption of the input-output budget could cause substantial changes in posted hospital rates in individual departments but probably would have no impact on hospital output determination. The input-output approach promises to be a more accurate system for cost control and planning because, unlike the conventional approach, it generates objective signals for investigating variances of expenses from budgeted levels. PMID:1205865

Kinin B1 receptor blockade and ACE inhibition attenuate cardiac postinfarction remodeling and heart failure in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Xinchun

Introduction: The aim of the present study was to evaluate the effects of the novel kinin B1 receptor antagonist BI113823 on postinfarction cardiac remodeling and heart failure, and to determine whether B1 receptor blockade alters the cardiovascular effects of an angiotensin 1 converting enzyme (ACE) inhibitor in rats. Methods and results: Sprague Dawley rats were subjected to permanent occlusion of the left coronary artery. Cardiovascular function was determined at 6 weeks postinfarction. Treatment with either B1 receptor antagonist (BI113823) or an ACE inhibitor (lisinopril) alone or in combination significantly reduced the heart weight-to-body weight and lung weight-to-body weight ratios, andmore » improved postinfarction cardiac function as evidenced by greater cardiac output, the maximum rate of left ventricular pressure rise (± dP/dtmax), left ventricle ejection fraction, fractional shorting, better wall motion, and attenuation of elevated left ventricular end diastolic pressure (LVEDP). Furthermore, all three treatment groups exhibited significant reduction in cardiac interstitial fibrosis, collagen deposition, CD68 positive macrophages, neutrophils, and proinflammatory cytokine production (TNF-α and IL-1β), compared to vehicle controls. Conclusion: The present study shows that treatment with the novel kinin B1 receptor antagonist, BI113823, reduces postinfarction cardiac remodeling and heart failure, and does not influence the cardiovascular effects of the ACE inhibitor. - Highlights: • We examined the role of kinin B1 receptors in the development of heart failure. • Kinin B1 receptor blockade attenuates post-infarction cardiac remodeling. • Kinin B1 receptor blockade improves dysfunction, and prevented heart failure. • B1 receptor blockade does not affect the cardio-protection of an ACE inhibitor.« less

Caffeoylxanthiazonoside exerts cardioprotective effects during chronic heart failure via inhibition of inflammatory responses in cardiac cells.

PubMed

Yang, Bin; Wang, Fei; Cao, Huili; Liu, Guifang; Zhang, Yuean; Yan, Ping; Li, Bao

2017-11-01

Caffeoylxanthiazonoside (CYT) is an active constituent isolated from the fruit of the Xanthium strumarium L plant. The aim of the present study was to investigate the cardioprotective effects of oral administration of CYT on chronic heart failure (CHF) and its underlying mechanisms. A rat model of CHF was first established, and cardiac function indices, including the heart/body weight index, left heart/body weight index, fractional shortening (FS), ejection fraction (EF), cardiac output (CO) and heart rate (HR), were subsequently determined by cardiac ultrasound. Serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK), and the levels of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β in heart tissues and cardiac microvascular endothelial cells (CMECs) were determined using ELISA. In addition, the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway members were determined by western blotting in CMECs. The results demonstrated that oral administration of 10, 20, 40 mg/kg CYT significantly reduced cardiac hypertrophy and reversed FS, EF, CO and HR when compared with CHF model rats. In addition, CYT administration significantly decreased the levels of TNF-α, IL-6 and IL-1β in heart tissues, as well as serum LDH and CK levels. Furthermore, exposure of CMECs to 20, 40 and 80 µg/ml CYT significantly decreased the production of TNF-α, IL-1β and IL-6. The protein expression levels of cytoplasmic NF-κB p65 and IκB were upregulated, while nuclear NF-κB p65 was downregulated following treatment of CMECs with 20, 40 and 80 µg/ml CYT when compared with untreated CHF model controls. In conclusion, the results of the current study suggest that CYT demonstrates cardioprotective effects in CHF model rats by suppressing the expression of pro-inflammatory cytokines and the NF-κB signaling pathway.

Molecular Mechanisms Underlying Cardiac Adaptation to Exercise

PubMed Central

Vega, Rick B.; Konhilas, John P.; Kelly, Daniel P.; Leinwand, Leslie A.

2017-01-01

Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations. PMID:28467921

A New Frontier for Cardiac Monitoring

NASA Technical Reports Server (NTRS)

2001-01-01

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.

[Cardiac index, oxygen and serum lactate consumption in infants with hypovolemic and septic shock].

PubMed

Gaytán Becerril, A; Olvera Hidalgo, C; Vieto Rodríguez, E E; Chávez Angeles, D S; Elena Salas, M

1980-01-01

Determination was made of cardiac output (using the stain dilution technique), gases in blood and serum lactate levels in eight infants with hypovolemic shock and sixteen with septic shock. The data were carried to indexes (values per square meter of body surface). In children with hypovolemic shock the cardiac index was 1.88 +/- 0.031/min/m,2 while in septic patients it was 4.02 +/- 1.011/min/m2. The peripheral resistances were 3,079 din/min/cm.5 in hypovolemic cases and 907 din/min in the septic. In both groups serum lactante levels rised close to 4 mM 61. Oxigen consumption was found low in hypovolemic patients and slightly high in the septic. It is concluded that our data are similar to those reported in similar studies in adults and hypodynamic shock is shown in hypovolemic patients, while hyperdynamic shock appears in septic cases.

Nandrolone decanoate determines cardiac remodelling and injury by an imbalance in cardiac inflammatory cytokines and ACE activity, blunting of the Bezold-Jarisch reflex, resulting in the development of hypertension.

PubMed

Franquni, João Vicente Maggioni; do Nascimento, Andrews Marques; de Lima, Eweliny Miranda; Brasil, Girlândia Alexandre; Heringer, Otávio Arruda; Cassaro, Karla Oliveira Dos Santos; da Cunha, Thony Vinicius Pita; Musso, Carlos; Silva Santos, Maria Carmen L F; Kalil, Ieda Carneiro; Endringer, Denise Coutinho; Boëchat, Giovanna Assis Pereirra; Bissoli, Nazaré Souza; de Andrade, Tadeu Uggere

2013-03-01

The aims of this study were to evaluate the effects of nandrolone (ND) on cardiac inflammatory cytokines, ACE activity, troponin I, and the sensitivity of the Bezold-Jarisch reflex (BJR). Male Wistar rats were administered either ND (20 mg/kg; DECA) or vehicle (control animals; CONT) for 4 weeks. BJR was analyzed by measuring the bradycardia and hypotension responses elicited by serotonin administration (2-32 μg/kg). Mean arterial pressure (MAP) was assessed and myocyte hypertrophy was determined by the heart weight/body weight ratio and by morphometric analysis. Matrix collagen deposition was assessed by histological analysis of the picrosirius red-stained samples. Mesenteric vascular reactivity was performed and central venous pressure (CVP) evaluated. Cardiac inflammatory cytokine levels and angiotensin-converting enzyme (ACE) activity were studied as well the biomarker of cardiac lesion, troponin I. DECA group showed enhancement of matrix type I collagen deposition (p < 0.01) and cardiac ACE activity (p < 0.01) compared with the CONT. Interleukin (IL)-10 was reduced (p < 0.01) and pro-inflammatory cytokines (TNF-α and IL-6; p < 0.01) were increased in the DECA group compared with CONT. Cardiac injury was observed in the DECA group shown by the reduction in cardiac troponin I (p < 0.01) compared with the CONT group. Animals in the DECA group also developed myocyte hypertrophy and reduction of BJR sensitivity. The MAP of animals treated with ND reached hypertensive levels (p < 0.01; compared with CONT). No changes in CVP and vascular reactivity were observed in both experimental groups. We conclude that high doses of ND elicit cardiotoxic effects with cardiac remodelling and injury. Cardiac changes reduce the BJR sensitivity. Together, these abnormalities contributed to the development of hypertension in animals in the DECA group. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of Obesity on Cardiovascular Hemodynamics, Cardiac Morphology, and Ventricular Function.

PubMed

Alpert, Martin A; Omran, Jad; Bostick, Brian P

2016-12-01

Obesity produces a variety of hemodynamic alterations that may cause changes in cardiac morphology which predispose to left and right ventricular dysfunction. Various neurohormonal and metabolic alterations commonly associated with obesity may contribute to these abnormalities of cardiac structure and function. These changes in cardiovascular hemodynamics, cardiac morphology, and ventricular function may, in severely obese patients, predispose to heart failure, even in the absence of other forms of heart disease (obesity cardiomyopathy). In normotensive obese patients, cardiac involvement is commonly characterized by elevated cardiac output, low peripheral vascular resistance, and increased left ventricular (LV) end-diastolic pressure. Sleep-disordered breathing may lead to pulmonary arterial hypertension and, in association with left heart failure, may contribute to elevation of right heart pressures. These alterations, in association with various neurohormonal and metabolic abnormalities, may produce LV hypertrophy; impaired LV diastolic function; and less commonly, LV systolic dysfunction. Many of these alterations are reversible with substantial voluntary weight loss.

Determination of cardiac size from chest roentgenograms following Skylab missions

NASA Technical Reports Server (NTRS)

Nicogossian, A. E.; Hoffler, G. W.; Johnson, R. L.; Gowen, R. J.

1977-01-01

The majority of crewmembers who exhibited postflight decreases in the cardiac silhouette size also showed a decreased orthostatic tolerance to lower body negative pressure. Similar findings were also reported by the Soviet investigators following 30-day bedrest studies and in cosmonauts upon return from space missions. Further radiological data from all three Skylab manned missions are presented and the physiological factors possibly involved in the cardiac silhouette changes are discussed.

Inverter communications using output signal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Patrick L.

Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

Characterization of glutamatergic neurons in the rat atrial intrinsic cardiac ganglia that project to the cardiac ventricular wall.

PubMed

Wang, Ting; Miller, Kenneth E

2016-08-04

The intrinsic cardiac nervous system modulates cardiac function by acting as an integration site for regulating autonomic efferent cardiac output. This intrinsic system is proposed to be composed of a short cardio-cardiac feedback control loop within the cardiac innervation hierarchy. For example, electrophysiological studies have postulated the presence of sensory neurons in intrinsic cardiac ganglia (ICG) for regional cardiac control. There is still a knowledge gap, however, about the anatomical location and neurochemical phenotype of sensory neurons inside ICG. In the present study, rat ICG neurons were characterized neurochemically with immunohistochemistry using glutamatergic markers: vesicular glutamate transporters 1 and 2 (VGLUT1; VGLUT2), and glutaminase (GLS), the enzyme essential for glutamate production. Glutamatergic neurons (VGLUT1/VGLUT2/GLS) in the ICG that have axons to the ventricles were identified by retrograde tracing of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected in the ventricular wall. Co-labeling of VGLUT1, VGLUT2, and GLS with the vesicular acetylcholine transporter (VAChT) was used to evaluate the relationship between post-ganglionic autonomic neurons and glutamatergic neurons. Sequential labeling of VGLUT1 and VGLUT2 in adjacent tissue sections was used to evaluate the co-localization of VGLUT1 and VGLUT2 in ICG neurons. Our studies yielded the following results: (1) ICG contain glutamatergic neurons with GLS for glutamate production and VGLUT1 and 2 for transport of glutamate into synaptic vesicles; (2) atrial ICG contain neurons that project to ventricle walls and these neurons are glutamatergic; (3) many glutamatergic ICG neurons also were cholinergic, expressing VAChT; (4) VGLUT1 and VGLUT2 co-localization occurred in ICG neurons with variation of their protein expression level. Investigation of both glutamatergic and cholinergic ICG neurons could help in better understanding the function of the intrinsic cardiac

Radiation dose in 320-slice multidetector cardiac CT: a single center experience of evolving dose minimization.

PubMed

Tung, Matthew K; Cameron, James D; Casan, Joshua M; Crossett, Marcus; Troupis, John M; Meredith, Ian T; Seneviratne, Sujith K

2013-01-01

Minimization of radiation exposure remains an important subject that occurs in parallel with advances in scanner technology. We report our experience of evolving radiation dose and its determinants after the introduction of 320-multidetector row cardiac CT within a single tertiary cardiology referral service. Four cohorts of consecutive patients (total 525 scans), who underwent cardiac CT at defined time points as early as 2008, are described. These include a cohort just after scanner installation, after 2 upgrades of the operating system, and after introduction of an adaptive iterative image reconstruction algorithm. The proportions of nondiagnostic coronary artery segments and studies with nondiagnostic segments were compared between cohorts. Significant reductions were observed in median radiation doses in all cohorts compared with the initial cohort (P < .001). Median dose-length product fell from 944 mGy · cm (interquartile range [IQR], 567.3-1426.5 mGy · cm) to 156 mGy · cm (IQR, 99.2-265.0 mGy · cm). Although the proportion of prospectively triggered scans has increased, reductions in radiation dose have occurred independently of distribution of scan formats. In multiple regression that combined all groups, determinants of dose-length product were tube output, the number of cardiac cycles scanned, tube voltage, scan length, scan format, body mass index, phase width, and heart rate (adjusted R(2) = 0.85, P < .001). The proportion of nondiagnostic coronary artery segments was slightly increased in group 4 (2.9%; P < .01). While maintaining diagnostic quality in 320-multidetector row cardiac CT, the radiation dose has decreased substantially because of a combination of dose-reduction protocols and technical improvements. Continued minimization of radiation dose will increase the potential for cardiac CT to expand as a cardiac imaging modality. Copyright © 2013 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Transcriptional Reversion of Cardiac Myocyte Fate During Mammalian Cardiac Regeneration

PubMed Central

O’Meara, Caitlin C.; Wamstad, Joseph A.; Gladstone, Rachel; Fomovsky, Gregory M.; Butty, Vincent L.; Shrikumar, Avanti; Gannon, Joseph; Boyer, Laurie A.; Lee, Richard T.

2014-01-01

Rationale Neonatal mice have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. The transcriptional changes that underpin mammalian cardiac regeneration have not been fully characterized at the molecular level. Objective The objectives of our study were to determine if myocytes revert the transcriptional phenotype to a less differentiated state during regeneration and to systematically interrogate the transcriptional data to identify and validate potential regulators of this process. Methods and Results We derived a core transcriptional signature of injury-induced cardiac myocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiac myocyte differentiation, in vitro cardiac myocyte explant model, as well as a neonatal heart resection model. The regenerating mouse heart revealed a transcriptional reversion of cardiac myocyte differentiation processes including reactivation of latent developmental programs similar to those observed during de-stabilization of a mature cardiac myocyte phenotype in the explant model. We identified potential upstream regulators of the core network, including interleukin 13 (IL13), which induced cardiac myocyte cell cycle entry and STAT6/STAT3 signaling in vitro. We demonstrate that STAT3/periostin and STAT6 signaling are critical mediators of IL13 signaling in cardiac myocytes. These downstream signaling molecules are also modulated in the regenerating mouse heart. Conclusions Our work reveals new insights into the transcriptional regulation of mammalian cardiac regeneration and provides the founding circuitry for identifying potential regulators for stimulating heart regeneration. PMID:25477501

Influence of water immersion, water gymnastics and swimming on cardiac output in patients with heart failure

PubMed Central

Schmid, Jean‐Paul; Noveanu, Markus; Morger, Cyrill; Gaillet, Raymond; Capoferri, Mauro; Anderegg, Matthias; Saner, Hugo

2007-01-01

Background Whole‐body water immersion leads to a significant shift of blood from the periphery to the intrathoracic circulation, followed by an increase in central venous pressure and heart volume. In patients with severely reduced left ventricular function, this hydrostatically induced volume shift might overstrain the cardiovascular adaptive mechanisms and lead to cardiac decompensation. Aim To assess the haemodynamic response to water immersion, gymnastics and swimming in patients with chronic heart failure (CHF). Methods 10 patients with compensated CHF (62.9 (6.3) years, ejection fraction 31.5% (4.1%), peak oxygen consumption (V̇o2) 19.4 (2.8) ml/kg/min), 10 patients with coronary artery disease (CAD) but preserved left ventricular function (57.2 (5.6) years, ejection fraction 63.9% (5.5%), peak V̇o2 28 (6.3) ml/kg/min), and 10 healthy controls (32.8 (7.2) years, peak V̇o2 45.6 (6) ml/kg/min) were examined. Haemodynamic response to thermoneutral (32°C) water immersion and exercise was measured using a non‐invasive foreign gas rebreathing method during stepwise water immersion, water gymnastics and swimming. Results Water immersion up to the chest increased cardiac index by 19% in controls, by 21% in patients with CAD and by 16% in patients with CHF. Although some patients with CHF showed a decrease of stroke volume during immersion, all subjects were able to increase cardiac index (by 87% in healthy subjects, by 77% in patients with CAD and by 53% in patients with CHF). V̇o2 during swimming was 9.7 (3.3) ml/kg/min in patients with CHF, 12.4 (3.5) ml/kg/min in patients with CAD and 13.9 (4) ml/kg/min in controls. Conclusions Patients with severely reduced left ventricular function but stable clinical conditions and a minimal peak V̇o2 of at least 15 ml/kg/min during a symptom‐limited exercise stress test tolerate water immersion and swimming in thermoneutral water well. Although cardiac index and V̇o2 are lower than in patients

SU-E-T-469: A Practical Approach for the Determination of Small Field Output Factors Using Published Monte Carlo Derived Correction Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calderon, E; Siergiej, D

2014-06-01

Purpose: Output factor determination for small fields (less than 20 mm) presents significant challenges due to ion chamber volume averaging and diode over-response. Measured output factor values between detectors are known to have large deviations as field sizes are decreased. No set standard to resolve this difference in measurement exists. We observed differences between measured output factors of up to 14% using two different detectors. Published Monte Carlo derived correction factors were used to address this challenge and decrease the output factor deviation between detectors. Methods: Output factors for Elekta's linac-based stereotactic cone system were measured using the EDGE detectormore » (Sun Nuclear) and the A16 ion chamber (Standard Imaging). Measurements conditions were 100 cm SSD (source to surface distance) and 1.5 cm depth. Output factors were first normalized to a 10.4 cm × 10.4 cm field size using a daisy-chaining technique to minimize the dependence of field size on detector response. An equation expressing the relation between published Monte Carlo correction factors as a function of field size for each detector was derived. The measured output factors were then multiplied by the calculated correction factors. EBT3 gafchromic film dosimetry was used to independently validate the corrected output factors. Results: Without correction, the deviation in output factors between the EDGE and A16 detectors ranged from 1.3 to 14.8%, depending on cone size. After applying the calculated correction factors, this deviation fell to 0 to 3.4%. Output factors determined with film agree within 3.5% of the corrected output factors. Conclusion: We present a practical approach to applying published Monte Carlo derived correction factors to measured small field output factors for the EDGE and A16 detectors. Using this method, we were able to decrease the percent deviation between both detectors from 14.8% to 3.4% agreement.« less

Chronic fatigue syndrome: illness severity, sedentary lifestyle, blood volume and evidence of diminished cardiac function.

PubMed

Hurwitz, Barry E; Coryell, Virginia T; Parker, Meela; Martin, Pedro; Laperriere, Arthur; Klimas, Nancy G; Sfakianakis, George N; Bilsker, Martin S

2009-10-19

The study examined whether deficits in cardiac output and blood volume in a CFS (chronic fatigue syndrome) cohort were present and linked to illness severity and sedentary lifestyle. Follow-up analyses assessed whether differences in cardiac output levels between CFS and control groups were corrected by controlling for cardiac contractility and TBV (total blood volume). The 146 participants were subdivided into two CFS groups based on symptom severity data, severe (n=30) and non-severe (n=26), and two healthy non-CFS control groups based on physical activity, sedentary (n=58) and non-sedentary (n=32). Controls were matched to CFS participants using age, gender, ethnicity and body mass. Echocardiographic measures indicated that the severe CFS participants had 10.2% lower cardiac volume (i.e. stroke index and end-diastolic volume) and 25.1% lower contractility (velocity of circumferential shortening corrected by heart rate) than the control groups. Dual tag blood volume assessments indicated that the CFS groups had lower TBV, PV (plasma volume) and RBCV (red blood cell volume) than control groups. Of the CFS subjects with a TBV deficit (i.e. > or = 8% below ideal levels), the mean+/-S.D. percentage deficit in TBV, PV and RBCV were -15.4+/-4.0, -13.2+/-5.0 and -19.1+/-6.3% respectively. Lower cardiac volume levels in CFS were substantially corrected by controlling for prevailing TBV deficits, but were not affected by controlling for cardiac contractility levels. Analyses indicated that the TBV deficit explained 91-94% of the group differences in cardiac volume indices. Group differences in cardiac structure were offsetting and, hence, no differences emerged for left ventricular mass index. Therefore the findings indicate that lower cardiac volume levels, displayed primarily by subjects with severe CFS, were not linked to diminished cardiac contractility levels, but were probably a consequence of a co-morbid hypovolaemic condition. Further study is needed to address

Diagnostic value of quantitative assessment of cardiac 18F-fluoro-2-deoxyglucose uptake in suspected cardiac sarcoidosis.

PubMed

Lebasnier, Adrien; Legallois, Damien; Bienvenu, Boris; Bergot, Emmanuel; Desmonts, Cédric; Zalcman, Gérard; Agostini, Denis; Manrique, Alain

2018-06-01

The identification of cardiac sarcoidosis is challenging as there is no gold standard consensually admitted for its diagnosis. The aim of this study was to evaluate the diagnostic value of the assessment of cardiac dynamic 18 F-fluoro-2-deoxyglucose positron emission tomography ( 18 F-FDG PET/CT) and net influx constant (Ki) in patients suspected of cardiac sarcoidosis. Data obtained from 30 biopsy-proven sarcoidosis patients suspected of cardiac sarcoidosis who underwent a 50-min list-mode cardiac dynamic 18 F-FDG PET/CT after a 24 h high-fat and low-carbohydrate diet were analyzed. A normalized coefficient of variation of quantitative glucose influx constant, calculated as the ratio: standard deviation of the segmental Ki (min -1 )/global Ki (min -1 ) was determined using a validated software (Carimas ® 2.4, Turku PET Centre). Cardiac sarcoidosis was diagnosed according to the Japanese Ministry of Health and Welfare criteria. Receiving operating curve analysis was performed to determine sensitivity and specificity of cardiac dynamic 18 F-FDG PET/CT analysis to diagnose cardiac sarcoidosis. Six out of 30 patients (20%) were diagnosed as having cardiac sarcoidosis. Myocardial glucose metabolism was significantly heterogeneous in patients with cardiac sarcoidosis who showed significantly higher normalized coefficient of variation values compared to patients without cardiac sarcoidosis (0.513 ± 0.175 vs. 0.205 ± 0.081; p = 0.0007). Using ROC curve analysis, we found a cut-off value of 0.38 for the diagnosis of cardiac sarcoidosis with a sensitivity of 100% and a specificity of 91%. Our results suggest that quantitative analysis of cardiac dynamic 18 F-FDG PET/CT could be a useful tool for the diagnosis of cardiac sarcoidosis.

Closed-chest cardiopulmonary bypass and cardioplegia: basis for less invasive cardiac surgery.

PubMed

Peters, W S; Siegel, L C; Stevens, J H; St Goar, F G; Pompili, M F; Burdon, T A

1997-06-01

We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed. Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter. Cardiopulmonary bypass time was 111 +/- 27 minutes (mean +/- standard deviation) and cardiac arrest time was 66 +/- 21 minutes. Preoperative cardiac outputs were 2.9 +/- 0.70 L/min and postoperative outputs were 2.9 +/- 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially. Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.

Eccentric and concentric cardiac hypertrophy induced by exercise training: microRNAs and molecular determinants.

PubMed

Fernandes, T; Soci, U P R; Oliveira, E M

2011-09-01

Among the molecular, biochemical and cellular processes that orchestrate the development of the different phenotypes of cardiac hypertrophy in response to physiological stimuli or pathological insults, the specific contribution of exercise training has recently become appreciated. Physiological cardiac hypertrophy involves complex cardiac remodeling that occurs as an adaptive response to static or dynamic chronic exercise, but the stimuli and molecular mechanisms underlying transduction of the hemodynamic overload into myocardial growth are poorly understood. This review summarizes the physiological stimuli that induce concentric and eccentric physiological hypertrophy, and discusses the molecular mechanisms, sarcomeric organization, and signaling pathway involved, also showing that the cardiac markers of pathological hypertrophy (atrial natriuretic factor, β-myosin heavy chain and α-skeletal actin) are not increased. There is no fibrosis and no cardiac dysfunction in eccentric or concentric hypertrophy induced by exercise training. Therefore, the renin-angiotensin system has been implicated as one of the regulatory mechanisms for the control of cardiac function and structure. Here, we show that the angiotensin II type 1 (AT1) receptor is locally activated in pathological and physiological cardiac hypertrophy, although with exercise training it can be stimulated independently of the involvement of angiotensin II. Recently, microRNAs (miRs) have been investigated as a possible therapeutic approach since they regulate the translation of the target mRNAs involved in cardiac hypertrophy; however, miRs in relation to physiological hypertrophy have not been extensively investigated. We summarize here profiling studies that have examined miRs in pathological and physiological cardiac hypertrophy. An understanding of physiological cardiac remodeling may provide a strategy to improve ventricular function in cardiac dysfunction.

Impaired left ventricular systolic function reserve limits cardiac output and exercise capacity in HFpEF patients due to systemic hypertension.

PubMed

Henein, Michael; Mörner, Stellan; Lindmark, Krister; Lindqvist, Per

2013-09-30

Heart failure (HF) patients with preserved left ventricular (LV) ejection fraction (EF) (HFpEF) due to systemic hypertension (SHT) are known to have limited exercise tolerance. Despite having normal EF at rest, we hypothesize that these patients have abnormal systolic function reserve limiting their exercise capacity. Seventeen patients with SHT (mean age 68 ± 9 years) but no valve disease and 14 healthy individuals (mean age of 65 ± 10 years) underwent resting and peak exercise echocardiography using conventional, tissue Doppler and speckle tracking techniques. The differences between resting and peak exercise values were also analyzed (Δ). Exercise capacity was determined as the workload divided by body surface area. Resting values for left atrial (LA) volume/BSA (r=-0.66, p<0.001) and global longitudinal strain rate (GLSR) in early (e) and late (a) diastole (r=0.47 and 0.46, p<0.05 for both) correlated with exercise capacity. LVEF increased during exercise in normals (mean Δ EF=10 ± 8%) but failed to do so in patients (mean Δ EF=0.6 ± 9%, p<0.001 between groups). LV GLSR during systole (s) also failed to increase with exercise in patients, to the same extent as it did in normals (0.2 ± 0.2 vs. 0.6 ± 0.3 1/s, p<0.001). The difference between rest and exercise (Δ) in LV lateral wall systolic velocity from tissue Doppler (s') (0.71, p<0.001), Δ in cardiac output (r=0.60, p<0.001) and Δ GLSRs (r=0.48, p<0.05) all correlated with exercise capacity independent of changes in heart rate. HFpEF patients with hypertensive LV disease have significantly limited exercise capacity which is related to left atrial enlargement as well as compromised LV systolic function at the time of the symptoms. The limited myocardial systolic function reserve seems to be underlying important explanation for their limited exercise capacity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Management of Complex Cardiac Issues in the Pregnant Patient.

PubMed

Hu, Huayong; Pasca, Ioana

2016-01-01

Management of peripartum heart disease in the intensive care unit requires optimization of maternal hemodynamics and maintenance of fetal perfusion. This requires fetal monitoring and should address the parturient's oxygen saturation, hemoglobin, and cardiac output as it relates to uterine blood flow. Pharmacologic strategies have limited evidence pertaining to hemodynamic stabilization and fetal perfusion. There is some evidence that surgical management of critical mitral stenosis should be percutaneous when possible because cardiac bypass is associated with increased fetal mortality. Fetal monitoring strategies should address central organ perfusion because peripheral scalp pH has not been associated with improved fetal outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

The determinants of dentists' productivity and the measurement of output.

PubMed

Gutacker, Nils; Harris, Anthony; Brennan, David; Hollingsworth, Bruce

2015-01-01

Improving the productivity of the healthcare system, for example by taking advantage of scale economies or encouraging substitution of expensive specialist personnel with less expensive workers, is often seen as an attractive way to meet increasing demand within a constrained budget. Using data on 558 dentists participating in the Longitudinal Study of Dentists' Practice Activity (LSDPA) survey between 1993 and 2003 linked to patient data and average fee schedules, we estimate production functions for private dental services in Australia to quantify the contribution of different capital and labour inputs and identify economies of scale in the production of dental care. Given the challenges in measuring output in the healthcare setting, we discuss three different output measures (raw activity, time-, and price-weighted activity) and test the sensitivity of results to the choice of measure. Our results suggest that expansion of the scale of dental services is unlikely to be constrained by decreasing returns to scale. We note that conclusions about the contribution of individual input factors and the estimated returns to scale are sensitive to the choice of output measure employed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dual-Energy Computed Tomography Gemstone Spectral Imaging: A Novel Technique to Determine Human Cardiac Calculus Composition.

PubMed

Cheng, Ching-Li; Chang, Hsiao-Huang; Ko, Shih-Chi; Huang, Pei-Jung; Lin, Shan-Yang

2016-01-01

Understanding the chemical composition of any calculus in different human organs is essential for choosing the best treatment strategy for patients. The purpose of this study was to assess the capability of determining the chemical composition of a human cardiac calculus using gemstone spectral imaging (GSI) mode on a single-source dual-energy computed tomography (DECT) in vitro. The cardiac calculus was directly scanned on the Discovery CT750 HD FREEdom Edition using GSI mode, in vitro. A portable fiber-optic Raman spectroscopy was also applied to verify the quantitative accuracy of the DECT measurements. The results of spectral DECT measurements indicate that effective Z values in 3 designated positions located in this calculus were 15.02 to 15.47, which are close to values of 15.74 to 15.86, corresponding to the effective Z values of calcium apatite and hydroxyapatite. The Raman spectral data were also reflected by the predominant Raman peak at 960 cm for hydroxyapatite and the minor peak at 875 cm for calcium apatite. A potential single-source DECT with GSI mode was first used to examine the morphological characteristics and chemical compositions of a giant human cardiac calculus, in vitro. The CT results were consistent with the Raman spectral data, suggesting that spectral CT imaging techniques could be accurately used to diagnose and characterize the compositional materials in the cardiac calculus.

Resolution of abnormal cardiac MRI T2 signal following immune suppression for cardiac sarcoidosis.

PubMed

Crouser, Elliott D; Ruden, Emily; Julian, Mark W; Raman, Subha V

2016-08-01

Cardiac MR (CMR) with late gadolinium enhancement is commonly used to detect cardiac damage in the setting of cardiac sarcoidosis. The addition of T2 mapping to CMR was recently shown to enhance cardiac sarcoidosis detection and correlates with increased cardiac arrhythmia risk. This study was conducted to determine if CMR T2 abnormalities and related arrhythmias are reversible following immune suppression therapy. A retrospective study of subjects with cardiac sarcoidosis with abnormal T2 signal on baseline CMR and a follow-up CMR study at least 4 months later was conducted at The Ohio State University from 2011 to 2015. Immune suppression treated participants had a significant reduction in peak myocardial T2 value (70.0±5.5 vs 59.2±6.1 ms, pretreatment vs post-treatment; p=0.017), and 83% of immune suppression treated subjects had objective improvement in cardiac arrhythmias. Two subjects who had received inadequate immune suppression treatment experienced progression of cardiac sarcoidosis. This report indicates that abnormal CMR T2 signal represents an acute inflammatory manifestation of cardiac sarcoidosis that is potentially reversible with adequate immune suppression therapy. Copyright © 2016 American Federation for Medical Research.

Acute cardiac support with intravenous milrinone promotes recovery from early brain injury in a murine model of severe subarachnoid haemorrhage.

PubMed

Mutoh, Tomoko; Mutoh, Tatsushi; Nakamura, Kazuhiro; Yamamoto, Yukiko; Tsuru, Yoshiharu; Tsubone, Hirokazu; Ishikawa, Tatsuya; Taki, Yasuyuki

2017-04-01

Early brain injury/ischaemia (EBI) is a serious complication early after subarachnoid haemorrhage (SAH) that contributes to development of delayed cerebral ischaemia (DCI). This study aimed to determine the role of inotropic cardiac support using milrinone (MIL) on restoring acute cerebral hypoperfusion attributable to EBI and improving outcomes after experimental SAH. Forty-three male C57BL/6 mice were assigned to either sham surgery (SAH-sham), SAH induced by endovascular perforation plus postconditioning with 2% isoflurane (Control), or SAH plus isoflurane combined with MIL with and without hypoxia-inducible factor inhibitor (HIF-I) pretreatment. Cardiac output (CO) during intravenous MIL infusion (0.25-0.75 μg/kg/min) between 1.5 and 2.5 hours after SAH induction was monitored with Doppler echocardiography. Magnetic resonance imaging (MRI)-continuous arterial spin labelling was used for quantitative cerebral blood flow (CBF) measurements. Neurobehavioral function was assessed daily by neurological score and open field test. DCI was analyzed 3 days later by determining infarction on MRI. Mild reduction of cardiac output (CO) and global cerebral blood flow (CBF) depression were notable early after SAH. MIL increased CO in a dose-dependent manner (P<.001), which was accompanied by improved hypoperfusion, incidence of DCI and functional recovery than Control (P<.05). The neuroprotective effects afforded by MIL or Control were attenuated by hypoxia-inducible factor (HIF) inhibition (P<.05). These results suggest that MIL improves acute hypoperfusion by its inotropic effect, leading to neurobehavioral improvement in mice after severe SAH, in which HIF may be acting as a critical mediator. © 2017 John Wiley & Sons Australia, Ltd.

Cardiac metabolism in the Myxinidae: physiological and phylogenetic considerations.

PubMed

Sidell, B D

1983-01-01

Cardiac muscle hearts of Atlantic hagfish continuously function under hypoxic conditions that would lead to cardiac failure in most other vertebrates. Contractile performance of hagfish systemic hearts is resistant to anoxia and respiratory poisons but shows a significant decrement when carbohydrate catabolism is blocked by 0.5 mM iodoacetic acid. Enzyme activity profiles of hagfish ventricle reveal a robust capacity for glycolysis of carbohydrate in comparison to that for general aerobic metabolism and catabolism of alternate metabolic fuels. Isolated working hagfish ventricles preferentially oxidize radiolabeled glucose even when fatty acid fuels are present in the incubation medium. Work output of the isolated ventricular preparation is maintained only in the presence of exogenous glucose. The results indicate that energy metabolism of the hagfish myocardium is predominantly carbohydrate-based and that energy demand of the tissue can be sustained by anaerobic glycolysis during extended periods of extreme hypoxia. Cardiac metabolism of this primitive species is compared with that of hearts from higher vertebrates and an evolutionary hypothesis relating cardiac workload to preferred metabolic fuel is discussed.

Length dependence of force generation exhibit similarities between rat cardiac myocytes and skeletal muscle fibres.

PubMed

Hanft, Laurin M; McDonald, Kerry S

2010-08-01

According to the Frank-Starling relationship, increased ventricular volume increases cardiac output, which helps match cardiac output to peripheral circulatory demand. The cellular basis for this relationship is in large part the myofilament length-tension relationship. Length-tension relationships in maximally calcium activated preparations are relatively shallow and similar between cardiac myocytes and skeletal muscle fibres. During twitch activations length-tension relationships become steeper in both cardiac and skeletal muscle; however, it remains unclear whether length dependence of tension differs between striated muscle cell types during submaximal activations. The purpose of this study was to compare sarcomere length-tension relationships and the sarcomere length dependence of force development between rat skinned left ventricular cardiac myocytes and fast-twitch and slow-twitch skeletal muscle fibres. Muscle cell preparations were calcium activated to yield 50% maximal force, after which isometric force and rate constants (k(tr)) of force development were measured over a range of sarcomere lengths. Myofilament length-tension relationships were considerably steeper in fast-twitch fibres compared to slow-twitch fibres. Interestingly, cardiac myocyte preparations exhibited two populations of length-tension relationships, one steeper than fast-twitch fibres and the other similar to slow-twitch fibres. Moreover, myocytes with shallow length-tension relationships were converted to steeper length-tension relationships by protein kinase A (PKA)-induced myofilament phosphorylation. Sarcomere length-k(tr) relationships were distinct between all three cell types and exhibited patterns markedly different from Ca(2+) activation-dependent k(tr) relationships. Overall, these findings indicate cardiac myocytes exhibit varied length-tension relationships and sarcomere length appears a dominant modulator of force development rates. Importantly, cardiac myocyte length

[Cardiac manifestations of sickle cell anemia].

PubMed

Gacon, P H; Donatien, Y

HEMOGLOBINS S AND C: Drepanocytosis, the occurrence of sickle cells (drepanocytes) in the blood, is an inherited condition. Electrophoresis demonstrates hemoglobin SS in homozygous subjects who present the typical clinical features of severe hemolytic sickle-cell anemia. Heterozygous subjects have sickle-cell anemia trait, an asymptomatic condition associated with a 50% hemoglobin S and 50% hemoglobin C at electrophoresis. Hemoglobin S and C are transmitted by Mendelian inheritance. CARDIAC DISORDERS: Well-known, cardiac disorders occur in more than 82% of homozygous subjects while only 2% of heterozygous subjects are affected. Heart murmur, radiological cardiomegaly, or eletrocardiographic anomalies are often the only signs. There is a risk of fatal heart failure in children and neonates. Acute rheumatic fever or infectious endocarditis, particularly due to pneumococcal or Haemophilus influenzae infection, may trigger heart failure. CARDIAC ANOMALIES: Patients with sickle-cell anemia can develop an "anemic heart" expressed by an elevated cardiac output and systemic ejection volume at rest and a fall in arteriolar peripheral resistance. Patients who develop cor pulmonae have an elevated pulmonary pressure at exercise and experience venous occlusive events with a progressive reduction in the pulmonary vascular bed and development of a left-right shunt. Myocardiopathy leads to left ventricular dysfunction contrasting with the dilated right heart seen at echocardiography and rare cases of transmural infarction.

Cumulative Burden of Myocardial Dysfunction in Cardiac Amyloidosis Assessed Using Four-Chamber Cardiac Strain.

PubMed

Kado, Yuichiro; Obokata, Masaru; Nagata, Yasufumi; Ishizu, Tomoko; Addetia, Karima; Aonuma, Kazutaka; Kurabayashi, Masahiko; Lang, Roberto M; Takeuchi, Masaaki; Otsuji, Yutaka

2016-11-01

The aim of this study was to test the hypothesis that prognosis in patients with cardiac amyloidosis is closely coupled with amyloid burden in all four cardiac chambers. The goal was to evaluate longitudinal strain (LS) in each cardiac chamber and to determine whether LS in specific cardiac chambers is preferentially associated with prognosis over conventional two-dimensional echocardiographic parameters in patients with cardiac amyloidosis. Patients with two phenotypes of left ventricular (LV) hypertrophy (cardiac amyloidosis in 55 patients and nonobstructive hypertrophic cardiomyopathy in 40 patients) and 55 healthy subjects were retrospectively enrolled for the simultaneous assessment of LS of all four cardiac chambers in the apical four-chamber view. Patients with cardiac amyloidosis were followed up to record major adverse cardiovascular events, including cardiac death, heart transplantation, nonfatal myocardial infarction, ventricular tachyarrhythmia, and exacerbation of heart failure requiring hospitalization. LS in each chamber was significantly depressed in patients with both LV hypertrophy phenotypes compared with healthy subjects. Right atrial LS was significantly lower in patients with cardiac amyloidosis than those with nonobstructive hypertrophic cardiomyopathy after adjusting for LV ejection fraction and LV mass index. During a median follow-up period of 10 months, major adverse cardiovascular events developed in 22 patients with cardiac amyloidosis. Four-chamber LS were significantly associated with major adverse cardiovascular events, with incremental value over traditional echocardiographic parameters. Cardiac amyloidosis involves all cardiac chambers, and thus, chamber-specific strain analysis may be useful to assess the total cumulative burden of cardiac dysfunction. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

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

PubMed

Brutsaert, Dirk L

2006-01-01

Translating research into clinical practice has been a challenge throughout medical history. From the present review, it should be clear that this is particularly the case for heart failure. As a consequence, public awareness of this disease has been disillusionedly low, despite its prognosis being worse than that of most cancers and many other chronic diseases. We explore how over the past 150 years since Ludwig and Marey concepts about the evaluation of cardiac performance in patients with heart failure have emerged. From this historical-physiologic perspective, we have seen how 3 increasingly reductionist approaches or schools of thought have evolved in parallel, that is, an input-output approach, a hemodynamic pump approach, and a muscular pump approach. Each one of these has provided complementary insights into the pathophysiology of heart failure and has resulted in measurements or derived indices, some of which still being in use in present-day cardiology. From the third, most reductionist muscular pump approach, we have learned that myocardial and ventricular relaxation properties as well as temporal and spatial nonuniformities have been largely overlooked in the 2 other, input-output and hemodynamic pump, approaches. A key message from the present review is that relaxation and nonuniformities can be fully understood only from within the time-space continuum of cardiac pumping. As cyclicity and rhythm are, in some way, the most basic aspects of cardiac function, considerations of time should dominate over any measurement of cardiac performance as a muscular pump. Any measurement that is blind for the arrow of cardiac time should therefore be interpreted with caution. We have seen how the escape from the time domain-as with the calculation of LV ejection fraction-fascinating though as it may be, has undoubtedly served to hinder a rational scientific debate on the recent, so-called systolic-diastolic heart failure controversy. Lacking appreciation of early

Cardiac Med1 deletion promotes early lethality, cardiac remodeling, and transcriptional reprogramming

PubMed Central

Spitler, Kathryn M.; Ponce, Jessica M.; Oudit, Gavin Y.; Hall, Duane D.

2017-01-01

The mediator complex, a multisubunit nuclear complex, plays an integral role in regulating gene expression by acting as a bridge between transcription factors and RNA polymerase II. Genetic deletion of mediator subunit 1 (Med1) results in embryonic lethality, due in large part to impaired cardiac development. We first established that Med1 is dynamically expressed in cardiac development and disease, with marked upregulation of Med1 in both human and murine failing hearts. To determine if Med1 deficiency protects against cardiac stress, we generated two cardiac-specific Med1 knockout mouse models in which Med1 is conditionally deleted (Med1cKO mice) or inducibly deleted in adult mice (Med1cKO-MCM mice). In both models, cardiac deletion of Med1 resulted in early lethality accompanied by pronounced changes in cardiac function, including left ventricular dilation, decreased ejection fraction, and pathological structural remodeling. We next defined how Med1 deficiency alters the cardiac transcriptional profile using RNA-sequencing analysis. Med1cKO mice demonstrated significant dysregulation of genes related to cardiac metabolism, in particular genes that are coordinated by the transcription factors Pgc1α, Pparα, and Errα. Consistent with the roles of these transcription factors in regulation of mitochondrial genes, we observed significant alterations in mitochondrial size, mitochondrial gene expression, complex activity, and electron transport chain expression under Med1 deficiency. Taken together, these data identify Med1 as an important regulator of vital cardiac gene expression and maintenance of normal heart function. NEW & NOTEWORTHY Disruption of transcriptional gene expression is a hallmark of dilated cardiomyopathy; however, its etiology is not well understood. Cardiac-specific deletion of the transcriptional coactivator mediator subunit 1 (Med1) results in dilated cardiomyopathy, decreased cardiac function, and lethality. Med1 deletion disrupted cardiac

Haemodynamic evidence for cardiac stress during transurethral prostatectomy.

PubMed Central

Evans, J. W.; Singer, M.; Chapple, C. R.; Macartney, N.; Walker, J. M.; Milroy, E. J.

1992-01-01

OBJECTIVE--To compare haemodynamic performance during transurethral prostatectomy and non-endoscopic control procedures similar in duration and surgical trauma. DESIGN--Controlled comparative study. SETTING--London teaching hospital. PATIENTS--33 men aged 50-85 years in American Society of Anesthesiologists risk groups I and II undergoing transurethral prostatectomy (20), herniorrhaphy (eight), or testicular exploration (five). MAIN OUTCOME MEASURES--Percentage change from baseline in mean arterial pressure, heart rate, Doppler indices of stroke volume and cardiac output, and index of systemic vascular resistance, and change from baseline in core temperature. RESULTS--In the control group mean arterial pressure fell to 11% (95% confidence interval -17% to -5%) below baseline at two minutes into surgery and remained below baseline; there were no other overall changes in haemodynamic variables and the core temperature was stable. During transurethral prostatectomy mean arterial pressure increased by 16% (5% to 27%) at the two minute recording and remained raised throughout. Bradycardia reached -7% (-14% to 1%) by the end of the procedure. Doppler indices of stroke volume fell progressively to 15% (-24% to -6%) below baseline at the end of the procedure, and the index of cardiac output fell to 21% (-32% to -10%) below baseline by the end of the procedure. The index of systemic vascular resistance was increased by 28% (17% to 38%) at two minutes, and by 46.8% (28% to 66%) at the end of the procedure. Core temperature fell by a mean of 0.8 (-1.0 to -0.6) degrees C. Significant differences existed between the two groups in summary measures of mean arterial pressure (p less than 0.05), Doppler indices of stroke volume (p less than 0.005) and cardiac output (p less than 0.005), index of systemic vascular resistance (p less than 0.0005), and core temperature (p less than 0.0001). CONCLUSIONS--Important haemodynamic disturbances were identified during routine apparently

Testing a Longitudinal Integrated Self-Efficacy and Self-Determination Theory Model for Physical Activity Post-Cardiac Rehabilitation

PubMed Central

Sweet, Shane N.; Fortier, Michelle S.; Strachan, Shaelyn M.; Blanchard, Chris M.; Boulay, Pierre

2014-01-01

Self-determination theory and self-efficacy theory are prominent theories in the physical activity literature, and studies have begun integrating their concepts. Sweet, Fortier, Strachan and Blanchard (2012) have integrated these two theories in a cross-sectional study. Therefore, this study sought to test a longitudinal integrated model to predict physical activity at the end of a 4-month cardiac rehabilitation program based on theory, research and Sweet et al.’s cross-sectional model. Participants from two cardiac rehabilitation programs (N=109) answered validated self-report questionnaires at baseline, two and four months. Data were analyzed using Amos to assess the path analysis and model fit. Prior to integration, perceived competence and self-efficacy were combined, and labeled as confidence. After controlling for 2-month physical activity and cardiac rehabilitation site, no motivational variables significantly predicted residual change in 4-month physical activity. Although confidence at two months did not predict residual change in 4-month physical activity, it had a strong positive relationship with 2-month physical activity (β=0.30, P<0.001). The overall model retained good fit indices. In conclusion, results diverged from theoretical predictions of physical activity, but self-determination and self-efficacy theory were still partially supported. Because the model had good fit, this study demonstrated that theoretical integration is feasible. PMID:26973926

Cardiac iodine-123-metaiodobenzylguanidine scintigraphy may be useful to identify pathologic from physiologic sinus bradycardia.

PubMed

Sunaga, Akihiro; Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Kanda, Takashi; Matsuda, Yasuhiro; Morozumi, Takakazu; Mano, Toshiaki; Uematsu, Masaaki

2017-06-01

Sinus bradycardia includes pathologic sick sinus syndrome (SSS) and physiologic bradycardia such as athletes' heart. Pacemaker implantation is indicated for patients with symptomatic SSS; however, the indication remains difficult to determine in those with mild and/or unspecific symptoms. The sympathetic tone is increased in response to reduced cardiac output in SSS, whereas excessive vagal tone has been seen in physiological bradycardia. We sought to determine if cardiac iodine-123-metaiodobenzylguanidine scintigraphy ( 123 I-MIBG) was useful in differentiating pathologic from physiologic sinus bradycardia. Twenty consecutive patients presenting with continuous sinus bradycardia (heart rate of <50 beats/min) in our outpatient clinic (male, eight patients; age, 70 ± 12 years old) were enrolled. The indication for a pacemaker implantation was determined by an experienced electrophysiologist in compliance with the international guidelines. The sympathetic nervous tone was assessed by cardiac 123 I-MIBG. Eight patients (40%) were clinically diagnosed as SSS (type I) including four suffering from obvious symptoms (syncope or dizziness) and four suffering from mild symptoms (fatigue), and had an indication for a pacemaker implantation. The patients with SSS indicated for a pacemaker implantation had a lower early heart-to-mediastinum ratio (2.0 ± 0.6 vs 2.5 ± 0.2, P = 0.043), lower delayed heart to mediastinum ratio (2.0 ± 0.8 vs 2.8 ± 0.3, P = 0.026), and higher washout rate (34 ± 6.0 vs 26 ± 6.0, P = 0.008) than those without. Excessive sympathetic tone detected by 123 I-MIBG may serve as an adjunct to determine the indication for a pacemaker implantation in sinus bradycardia. © 2017 Wiley Periodicals, Inc.

Effect of E-OJ-01 on Cardiac Conditioning in Young Exercising Adults: A Randomized Controlled Trial.

PubMed

Girandola, Robert N; Srivastava, Shalini

2017-05-01

Cardiac health is a determinant of athletic performance. A body of data suggests that in healthy young adults, an increase in maximal cardiac output leads to an increase in endurance. Terminalia arjuna (TA) has been studied for multiple benefits in cardiovascular health although its effects as a cardioprotective ergogenic aid require further exploration. The current trial was planned to study the effect of the proprietary TA extract (E-OJ-01) on the markers of cardiac conditioning in healthy young adults. No study has assessed the effect of TA extract on cardiac conditioning by improvement of left ventricular ejection fraction (LVEF) in young exercising individuals. A randomized, double-blind, placebo-controlled, parallel group study was conducted to determine the efficacy and safety of E-OJ-01 for use as an ergogenic supplements in young exercising adults. This trial was registered at ClinicalTrials.gov (NCT02207101) and reported according to Consolidated Standards of Reporting Trials (CONSORT) requirements. Thirty-two healthy males, aged 18-40 years performing regular endurance exercise, were randomly assigned to 400 mg of E-OJ-01 or placebo for 56 days. LVEF, right and left ventricular Myocardial Performance Index, and Borg Rated Perceived Exertion (RPE) were assessed at baseline, day 28, and day 56; creatine kinase-MB and troponin-T were assessed at baseline and at day 56. As compared with placebo, 56 days of E-OJ-01 supplementation significantly improved the LVEF (P = 0.0001) and decreased the right ventricular Myocardial Performance Index (P = 0.001). The fatigue level captured by Borg Scale after completion of exercise showed a greater decrease in the E-OJ-01 group as compared with placebo. Creatine kinase-MB and troponin-T did not change significantly. TA (E-OJ-01) significantly increased cardiovascular efficiency and improved the cardiac conditioning in young healthy adults.

Motivational processes and well-being in cardiac rehabilitation: a self-determination theory perspective.

PubMed

Rahman, Rachel Jane; Hudson, Joanne; Thøgersen-Ntoumani, Cecilie; Doust, Jonathan H

2015-01-01

This research examined the processes underpinning changes in psychological well-being and behavioural regulation in cardiac rehabilitation (CR) patients using self-determination theory (SDT). A repeated measures design was used to identify the longitudinal relationships between SDT variables, psychological well-being and exercise behaviour during and following a structured CR programme. Participants were 389 cardiac patients (aged 36-84 years; M(age) = 64 ± 9 years; 34.3% female) referred to a 12-week-supervised CR programme. Psychological need satisfaction, behavioural regulation, health-related quality of life, physical self-worth, anxiety and depression were measured at programme entry, exit and six month post-programme. During the programme, increases in autonomy satisfaction predicted positive changes in behavioural regulation, and improvements in competence and relatedness satisfaction predicted improvements in behavioural regulation and well-being. Competence satisfaction also positively predicted habitual physical activity. Decreases in external regulation and increases in intrinsic motivation predicted improvements in physical self-worth and physical well-being, respectively. Significant longitudinal relationships were identified whereby changes during the programme predicted changes in habitual physical activity and the mental quality of life from exit to six month follow-up. Findings provide insight into the factors explaining psychological changes seen during CR. They highlight the importance of increasing patients' perceptions of psychological need satisfaction and self-determined motivation to improve well-being during the structured component of a CR programme and longer term physical activity.

Caffeoylxanthiazonoside exerts cardioprotective effects during chronic heart failure via inhibition of inflammatory responses in cardiac cells

PubMed Central

Yang, Bin; Wang, Fei; Cao, Huili; Liu, Guifang; Zhang, Yuean; Yan, Ping; Li, Bao

2017-01-01

Caffeoylxanthiazonoside (CYT) is an active constituent isolated from the fruit of the Xanthium strumarium L plant. The aim of the present study was to investigate the cardioprotective effects of oral administration of CYT on chronic heart failure (CHF) and its underlying mechanisms. A rat model of CHF was first established, and cardiac function indices, including the heart/body weight index, left heart/body weight index, fractional shortening (FS), ejection fraction (EF), cardiac output (CO) and heart rate (HR), were subsequently determined by cardiac ultrasound. Serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK), and the levels of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β in heart tissues and cardiac microvascular endothelial cells (CMECs) were determined using ELISA. In addition, the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway members were determined by western blotting in CMECs. The results demonstrated that oral administration of 10, 20, 40 mg/kg CYT significantly reduced cardiac hypertrophy and reversed FS, EF, CO and HR when compared with CHF model rats. In addition, CYT administration significantly decreased the levels of TNF-α, IL-6 and IL-1β in heart tissues, as well as serum LDH and CK levels. Furthermore, exposure of CMECs to 20, 40 and 80 µg/ml CYT significantly decreased the production of TNF-α, IL-1β and IL-6. The protein expression levels of cytoplasmic NF-κB p65 and IκB were upregulated, while nuclear NF-κB p65 was downregulated following treatment of CMECs with 20, 40 and 80 µg/ml CYT when compared with untreated CHF model controls. In conclusion, the results of the current study suggest that CYT demonstrates cardioprotective effects in CHF model rats by suppressing the expression of pro-inflammatory cytokines and the NF-κB signaling pathway. PMID:29104638

Cardiac risk stratification in renal transplantation using a form of artificial intelligence.

PubMed

Heston, T F; Norman, D J; Barry, J M; Bennett, W M; Wilson, R A

1997-02-15

The purpose of this study was to determine if an expert network, a form of artificial intelligence, could effectively stratify cardiac risk in candidates for renal transplant. Input into the expert network consisted of clinical risk factors and thallium-201 stress test data. Clinical risk factor screening alone identified 95 of 189 patients as high risk. These 95 patients underwent thallium-201 stress testing, and 53 had either reversible or fixed defects. The other 42 patients were classified as low risk. This algorithm made up the "expert system," and during the 4-year follow-up period had a sensitivity of 82%, specificity of 77%, and accuracy of 78%. An artificial neural network was added to the expert system, creating an expert network. Input into the neural network consisted of both clinical variables and thallium-201 stress test data. There were 5 hidden nodes and the output (end point) was cardiac death. The expert network increased the specificity of the expert system alone from 77% to 90% (p < 0.001), the accuracy from 78% to 89% (p < 0.005), and maintained the overall sensitivity at 88%. An expert network based on clinical risk factor screening and thallium-201 stress testing had an accuracy of 89% in predicting the 4-year cardiac mortality among 189 renal transplant candidates.

C.A.U.S.E.: Cardiac arrest ultra-sound exam--a better approach to managing patients in primary non-arrhythmogenic cardiac arrest.

PubMed

Hernandez, Caleb; Shuler, Klaus; Hannan, Hashibul; Sonyika, Chionesu; Likourezos, Antonios; Marshall, John

2008-02-01

Cardiac arrest is a condition frequently encountered by physicians in the hospital setting including the Emergency Department, Intensive Care Unit and medical/surgical wards. This paper reviews the current literature involving the use of ultrasound in resuscitation and proposes an algorithmic approach for the use of ultrasound during cardiac arrest. At present there is the need for a means of differentiating between various causes of cardiac arrest, which are not a direct result of a primary ventricular arrhythmia. Identifying the cause of pulseless electrical activity or asystole is important as the underlying cause is what guides management in such cases. This approach, incorporating ultrasound to manage cardiac arrest aids in the diagnosis of the most common and easily reversible causes of cardiac arrest not caused by primary ventricular arrhythmia, namely; severe hypovolemia, tension pneumothorax, cardiac tamponade, and massive pulmonary embolus. These four conditions are addressed in this paper using four accepted emergency ultrasound applications to be performed during resuscitation of a cardiac arrest patient with the aim of determining the underlying cause of a cardiac arrest. Identifying the underlying cause of cardiac arrest represents the one of the greatest challenges of managing patients with asystole or PEA and accurate determination has the potential to improve management by guiding therapeutic decisions. We include several clinical images demonstrating examples of cardiac tamponade, massive pulmonary embolus, and severe hypovolemia secondary to abdominal aortic aneurysm. In conclusion, this protocol has the potential to reduce the time required to determine the etiology of a cardiac arrest and thus decrease the time between arrest and appropriate therapy.

Cardiac pathologic findings reveal a high rate of sudden cardiac death of undetermined etiology in younger women.

PubMed

Chugh, Sumeet S; Chung, Kiyon; Zheng, Zhi-Jie; John, Benjamin; Titus, Jack L

2003-10-01

Between 1989 and 1998 there was a 21% increase in estimated sudden cardiac death among US women aged 35 to 44 years. In contrast, the sudden cardiac death rate in age-matched men showed a decreasing trend (-2.8%). Due to under-representation of younger adults in published autopsy series, etiologies of sudden cardiac death merit further investigation. We reviewed autopsy and detailed cardiac pathologic findings in younger women (age 35-44 years) from a 270-patient, 13-year (1984-1996) autopsy series of sudden cardiac death, and performed comparisons with findings in age-matched men. Women aged 35 to 44 years constituted 32% of all women in the series compared to men, who constituted 24% of total men (P =.004 vs women). A presumptive cause of sudden cardiac death could not be determined in 13 women (50%). Among women, 6 cases (22%) had significant coronary artery disease. Findings in others included coronary artery anomalies (n = 3), myocarditis (n = 2), hypertrophic cardiomyopathy (n = 1), coronary artery dissection (n = 1) and accessory pathway (n = 1). In younger men, a presumptive cause of sudden cardiac death remained undetermined in only 24% (P =.025 vs younger women), and coronary artery disease accounted for 40% of cases. In younger women, despite autopsy and detailed cardiac pathologic examination, an attributable cause of sudden cardiac death was not determined in 50% of cases; a 2-fold increase compared to men of the same age. Given the dynamic and multifactorial nature of sudden cardiac death, comprehensive population-based investigations are likely to be necessary to further investigate this unexpected sex-based disparity.

Determinants of Long-Term Neurological Recovery Patterns Relative to Hospital Discharge Among Cardiac Arrest Survivors.

PubMed

Agarwal, Sachin; Presciutti, Alex; Roth, William; Matthews, Elizabeth; Rodriguez, Ashley; Roh, David J; Park, Soojin; Claassen, Jan; Lazar, Ronald M

2018-02-01

To explore factors associated with neurological recovery at 1 year relative to hospital discharge after cardiac arrest. Observational, retrospective review of a prospectively collected cohort. Medical or surgical ICUs in a single tertiary care center. Older than 18 years, resuscitated following either in-hospital or out-of-hospital cardiac arrest and considered for targeted temperature management between 2007 and 2013. None. Logistic regressions to determine factors associated with a poor recovery pattern after 1 year, defined as persistent Cerebral Performance Category Score 3-4 or any worsening of Cerebral Performance Category Score relative to discharge status. In total, 30% (117/385) of patients survived to hospital discharge; among those discharged with Cerebral Performance Category Score 1, 2, 3, and 4, good recovery pattern was seen in 54.5%, 48.4%, 39.5%, and 0%, respectively. Significant variables showing trends in associations with a poor recovery pattern (62.5%) in a multivariate model were age more than 70 years (odds ratio, 4; 95% CIs, 1.1-15; p = 0.04), Hispanic ethnicity (odds ratio, 4; CI, 1.2-13; p = 0.02), and discharge disposition (home needing out-patient services (odds ratio, 1), home requiring no additional services (odds ratio, 0.15; CI, 0.03-0.8; p = 0.02), acute rehabilitation (odds ratio, 0.23; CI, 0.06-0.9; p = 0.04). Patients discharged with mild or moderate cerebral dysfunction sustained their risk of neurological worsening within 1 year of cardiac arrest. Old age, Hispanic ethnicity, and discharge disposition of home with out-patient services may be associated with a poor 1 year neurological recovery pattern after hospital discharge from cardiac arrest.

Cardiac function, myocardial mechano-energetic efficiency, and ventricular-arterial coupling in normal pregnancy.

PubMed

Iacobaeus, Charlotte; Andolf, Ellika; Thorsell, Malin; Bremme, Katarina; Östlund, Eva; Kahan, Thomas

2018-04-01

To assess cardiac function, myocardial mechanoenergetic efficiency (MEE), and ventricular-arterial coupling (VAC) longitudinally during normal pregnancy, and to study if there was an association between cardiac structure and function, and fetal growth. Cardiac structure and function, MEE, and ventricular-arterial coupling was assessed longitudinally in 52 healthy nulliparous women at 14, 24, and 34 weeks' gestation and 9-month postpartum. Left atrial diameter increased during pregnancy (30.41 ± 3.59 mm in the nonpregnant state and 31.02 ± 3.91, 34.06 ± 3.58, and 33.9 ± 2.97 mm in the first, second, and third trimesters, P < 0.001). Left ventricular mass increased 117.12 ± 45.0 g in the nonpregnant state and 116.5 ± 33.0, 126.9 ± 34.5, 128.4 ± 36 g in the first, second, and third trimesters (P < 0.001). Cardiac output increased from 3.4 ± 1.2 l/min to 4.3 ± 0.7 l/min in the second and third trimesters (P < 0.001). Diastolic function decreased as both E/A and e'/a' decreased during pregnancy (P < 0.05 and P < 0.001, respectively). MEE and VAC were retained during pregnancy. Heart rate was associated with birth weight centile in the first (r = 0.41, P = 0.002) and second (r = 0.46, P = 0.002) trimester. The increase in cardiac output during normal pregnancy is obtained by an increase in heart rate, followed by structural cardiac changes. The impaired systolic function is accomplished by a deteriorated diastolic function. Despite these rapid changes, the myocardium manages to work efficient with a preserved MEE. Cardiac and arterial adaption to pregnancy seems to appear parallel as evidenced by a preserved VAC.

Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig

PubMed Central

Beaumont, Eric; Wright, Gary L.; Southerland, Elizabeth M.; Li, Ying; Chui, Ray; KenKnight, Bruce H.; Armour, J. Andrew

2016-01-01

Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15–20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling. PMID:26993230

The effect of intermittent intraabdominal pressure elevations and low cardiac output on the femoral to carotid arterial blood pressure difference in piglets.

PubMed

Aksakal, Devrim; Hückstädt, Thomas; Richter, Steffen; Klitscher, Daniela; Wowra, Tobias; Schier, Felix; Wessel, Lucas M; Kubiak, Rainer

2016-11-01

Our previous work in a laparoscopic setting in piglets revealed that the systolic femoral artery pressure was approximately 5 % higher than its carotid counterpart, whereas the mean and diastolic values showed no significant difference. This remained idem when the intraabdominal pressure (IAP) was gradually increased. In this study, we aimed to investigate the effect of (1) intermittent IAP elevations and (2) a low cardiac output (CO) on the blood pressure (BP) difference cranially (carotid artery) and caudally (femoral artery) of a capnoperitoneum (ΔP = P a fem -P a carot ). A total of twenty-two piglets (mean body weight 11.0 kg; range 8.9-13.3 kg) were studied. Of these, 14 underwent intermittent IAP elevations at 8 and 16 mmHg, and ΔP was measured. In another 8 piglets, a model of reduced CO was created by introducing an air embolism (2 ml/kg over 30 s) in the inferior caval vein (VCI) at 12 mmHg IAP to further assess the influence of this variable on ΔP. Systolic ΔP remained at a mean of 5.6 mmHg and was not significantly affected by insufflation or exsufflation up to an IAP of 16 mmHg. Diastolic and mean values showed no differences between P a carot and P a fem . P a fem, systol remained higher than its carotid counterpart as long as the cardiac index (CI) was above 1.5 l/min/m 2 , but fell significantly below P a carot, systol at a low CI. There was no CO-dependent effect on diastolic and mean ΔP. Repeated IAP elevations do not significantly influence ΔP. Intermittent IAP elevations do not significantly influence ΔP. Despite of a CO-dependent inversion of systolic ΔP, mean BP measurements at the leg during laparoscopy remain representative even at low CO values.

Clinical feasibility of exercise-based A-V interval optimization for cardiac resynchronization: a pilot study.

PubMed

Choudhuri, Indrajit; MacCarter, Dean; Shaw, Rachael; Anderson, Steve; St Cyr, John; Niazi, Imran

2014-11-01

One-third of eligible patients fail to respond to cardiac resynchronization therapy (CRT). Current methods to "optimize" the atrio-ventricular (A-V) interval are performed at rest, which may limit its efficacy during daily activities. We hypothesized that low-intensity cardiopulmonary exercise testing (CPX) could identify the most favorable physiologic combination of specific gas exchange parameters reflecting pulmonary blood flow or cardiac output, stroke volume, and left atrial pressure to guide determination of the optimal A-V interval. We assessed relative feasibility of determining the optimal A-V interval by three methods in 17 patients who underwent optimization of CRT: (1) resting echocardiographic optimization (the Ritter method), (2) resting electrical optimization (intrinsic A-V interval and QRS duration), and (3) during low-intensity, steady-state CPX. Five sequential, incremental A-V intervals were programmed in each method. Assessment of cardiopulmonary stability and potential influence on the CPX-based method were assessed. CPX and determination of a physiological optimal A-V interval was successfully completed in 94.1% of patients, slightly higher than the resting echo-based approach (88.2%). There was a wide variation in the optimal A-V delay determined by each method. There was no observed cardiopulmonary instability or impact of the implant procedure that affected determination of the CPX-based optimized A-V interval. Determining optimized A-V intervals by CPX is feasible. Proposed mechanisms explaining this finding and long-term impact require further study. ©2014 Wiley Periodicals, Inc.

Wireless Passive Stimulation of Engineered Cardiac Tissues.

PubMed

Liu, Shiyi; Navaei, Ali; Meng, Xueling; Nikkhah, Mehdi; Chae, Junseok

2017-07-28

We present a battery-free radio frequency (RF) microwave activated wireless stimulator, 25 × 42 × 1.6 mm 3 on a flexible substrate, featuring high current delivery, up to 60 mA, to stimulate engineered cardiac tissues. An external antenna shines 2.4 GHz microwave, which is modulated by an inverted pulse to directly control the stimulating waveform, to the wireless passive stimulator. The stimulator is equipped with an on-board antenna, multistage diode multipliers, and a control transistor. Rat cardiomyocytes, seeded on electrically conductive gelatin-based hydrogels, demonstrate synchronous contractions and Ca 2+ transients immediately upon stimulation. Notably, the stimulator output voltage and current profiles match the tissue contraction frequency within 0.5-2 Hz. Overall, our results indicate the promising potential of the proposed wireless passive stimulator for cardiac stimulation and therapy by induction of precisely controlled and synchronous contractions.

21 CFR 870.1220 - Electrode recording catheter or electrode recording probe.

Code of Federal Regulations, 2010 CFR

2010-04-01

... electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or... a special indicator for cardiac output or left-to-right heart shunt determinations. (b...

21 CFR 870.1220 - Electrode recording catheter or electrode recording probe.

Code of Federal Regulations, 2011 CFR

2011-04-01

... electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or... a special indicator for cardiac output or left-to-right heart shunt determinations. (b...

21 CFR 870.1220 - Electrode recording catheter or electrode recording probe.

Code of Federal Regulations, 2012 CFR

2012-04-01

... electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or... a special indicator for cardiac output or left-to-right heart shunt determinations. (b...

21 CFR 870.1220 - Electrode recording catheter or electrode recording probe.

Code of Federal Regulations, 2013 CFR

2013-04-01

... electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or... a special indicator for cardiac output or left-to-right heart shunt determinations. (b...

21 CFR 870.1220 - Electrode recording catheter or electrode recording probe.

Code of Federal Regulations, 2014 CFR

2014-04-01

... electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or... a special indicator for cardiac output or left-to-right heart shunt determinations. (b...

Increased cardiac work provides a link between systemic hypertension and heart failure.

PubMed

Wilson, Alexander J; Wang, Vicky Y; Sands, Gregory B; Young, Alistair A; Nash, Martyn P; LeGrice, Ian J

2017-01-01

The spontaneously hypertensive rat (SHR) is an established model of human hypertensive heart disease transitioning into heart failure. The study of the progression to heart failure in these animals has been limited by the lack of longitudinal data. We used MRI to quantify left ventricular mass, volume, and cardiac work in SHRs at age 3 to 21 month and compared these indices to data from Wistar-Kyoto (WKY) controls. SHR had lower ejection fraction compared with WKY at all ages, but there was no difference in cardiac output at any age. At 21 month the SHR had significantly elevated stroke work (51 ± 3 mL.mmHg SHR vs. 24 ± 2 mL.mmHg WKY; n = 8, 4; P < 0.001) and cardiac minute work (14.2 ± 1.2 L.mmHg/min SHR vs. 6.2 ± 0.8 L.mmHg/min WKY; n = 8, 4; P < 0.001) compared to control, in addition to significantly larger left ventricular mass to body mass ratio (3.61 ± 0.15 mg/g SHR vs. 2.11 ± 0.008 mg/g WKY; n = 8, 6; P < 0.001). SHRs showed impaired systolic function, but developed hypertrophy to compensate and successfully maintained cardiac output. However, this was associated with an increase in cardiac work at age 21 month, which has previously demonstrated fibrosis and cell death. The interplay between these factors may be the mechanism for progression to failure in this animal model. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Role of H-FABP values in determining the etiologic factors of the cardiac injuries.

PubMed

Akpinar, Guleser; Duman, Ali; Gulen, Bedia; Kapci, Mucahit; Altinbilek, Ertugrul; Ikizceli, Ibrahim

2017-01-01

Cardiac injury resulting from blunt thoracic trauma is a frequent clinical occurrence which is difficult to diagnose. Our purpose in this study was to research whether H-FABP, which is a new marker for the diagnosis of cardiac injury, can be used in this patient group. 50 patients with blunt thoracic injury who were admitted to our emergency service within a period of 8 months and 50 cases as controls were included in our study. Of the 50 patients with blunt thoracic injury in our study, 88% were male while 12% were female. The average age of the patients was 43 ± 15.15. While 27 (54%) of the 50 patients with blunt thoracic injury had cardiac injury, 23 (46%) did not have cardiac injury. The results of the statistical analyses showed a significant association between thorax trauma and cTnI, CPK, CPKMB and H-FABP (p<0.05). While there was a significant association between cardiac injury resulting from thoracic trauma and cTnI, ECG and TTE (p<0.05), there was no significant association between CPK, CPKMB and H-FABP (p>0.05). In thoracic traumas, cardiac injury diagnosis can be made as a result of the assessment with Troponin-I, ECG and ECHO. For cardiac injury diagnosis, wide scale prospective studies are needed for H-FABP use.

Hemodynamic effects of calcium antagonists in cardiac patients.

PubMed

Pozenel, H

1982-01-01

Hemodynamic studies were carried out after cardiac catheterization with a floatation catheter in the pulmonary artery and cannulation of the brachial artery for the calculation of cardiac output by means of the Fick principle. Continuous pressure recordings were carried out at rest and under submaximal treadmill exercise in the supine body position in 5 homogeneous groups of 12 patients, all with disorders due to coronary disease. In a control test, hemodynamic investigations were carried out at rest before medication, under stress and after recovery. Similar tests were performed after intravenous administration of either isotonic saline as placebo, tiapamil (1.1 and 1.6 mg/kg) or verapamil (0.07 and 0.14 mg/kg). It was shown that there was a marked dose-related reduction in peripheral vascular resistance with a maximum effect occurring at 2-5 min after the intravenous administration of tiapamil (1.1 and 1.6 mg/kg) reaching 23 and 39%, respectively, or verapamil (0.07 and 0.14 mg/kg) attaining 28 and 39%, respectively, at rest and, to a similar extent, under stress conditions. In patients with sinus rhythm, the mean arterial pressure was reduced. Cardiac outputs and stroke volumes were increased at rest as well as under stress. There was no evidence of a depressant action of the drug on hemodynamic variables. An interplay of simultaneous changes in preload and afterload seems to be responsible for the effects obtained. The doses used were those commonly employed in the termination of supraventricular tachyarrhythmias. However, a potential depressant effect of tiapamil in patients with markedly reduced ventricular function is not excluded by this study.

Donor age is a predictor of early low output after heart transplantation.

PubMed

Fujino, Takeo; Kinugawa, Koichiro; Nitta, Daisuke; Imamura, Teruhiko; Maki, Hisataka; Amiya, Eisuke; Hatano, Masaru; Kimura, Mitsutoshi; Kinoshita, Osamu; Nawata, Kan; Komuro, Issei; Ono, Minoru

2016-05-01

Using hearts from marginal donors could be related to increased risk of primary graft dysfunction and poor long-term survival. However, factors associated with delayed myocardial recovery after heart transplantation (HTx) remain unknown. We sought to clarify risk factors that predict early low output after HTx, and investigated whether early low output affects mid-term graft dysfunction. We retrospectively analyzed patients who had undergone HTx at The University of Tokyo Hospital. We defined early low output patients as those whose cardiac index (CI) was <2.2 L/min/m(2) despite the use of intravenous inotrope at 1 week after HTx. We included 45 consecutive HTx recipients, and classified 11 patients into early low output group, and the others into early preserved output group. We performed univariable logistic analysis and found that donor age was the only significant factor that predicted early low output (odds ratio 1.107, 95% confidence interval 1.034-1.210, p=0.002). CI of early low output patients gradually increased and it caught up with that of early preserved output patients at 2 weeks after HTx (2.4±0.6 L/min/m(2) in early low output group vs 2.5±0.5 L/min/m(2) in early preserved output group, p=0.684). Plasma B-type natriuretic peptide concentration of early low output patients was higher (1118.5±1250.2 pg/ml vs 526.4±399.5 pg/ml; p=0.033) at 1 week, 703.6±518.4 pg/ml vs 464.6±509.0 pg/ml (p=0.033) at 2 weeks, and 387.7±231.9 pg/ml vs 249.4±209.5 pg/ml (p=0.010) at 4 weeks after HTx, and it came down to that of early preserved output patients at 12 weeks after HTx. Donor age was a predictor of early low output after HTx. We should be careful after HTx from old donors. However, hemodynamic parameters of early low output patients gradually caught up with those of early preserved output patients. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Manual vs. automatic capture management in implantable cardioverter defibrillators and cardiac resynchronization therapy defibrillators.

PubMed

Murgatroyd, Francis D; Helmling, Erhard; Lemke, Bernd; Eber, Bernd; Mewis, Christian; van der Meer-Hensgens, Judith; Chang, Yanping; Khalameizer, Vladimir; Katz, Amos

2010-06-01

The Secura ICD and Consulta CRT-D are the first defibrillators to have automatic right atrial (RA), right ventricular (RV), and left ventricular (LV) capture management (CM). Complete CM was evaluated in an implantable cardioverter defibrillator (ICD) population. Two prospective clinical studies were conducted in 28 centres in Europe and Israel. Automatic CM data were compared with manual threshold measurements, the CM applicability was determined, and adjustments to pacing outputs were analysed. In total, 160 patients [age 64.6 +/- 10.4 years, 77% male, 80 ICD and 80 cardiac resynchronization therapy defibrillator (CRT-D)] were included. The differences between automatic and manual measurements were output (threshold >2.5 V) due to raised RA threshold in seven (4.4%), high RV threshold in nine (5.6%), and high LV threshold in three patients (3.8%). All high threshold detections and all automatic modulations of pacing output were adjudicated appropriate. Complete CM adjusts pacing output appropriately, permitting a reduction in office visits while it may maximize device longevity. The study was registered at ClinicalTrials.gov identifiers: NCT00526227 and NCT00526162.

Design and testing of an MRI-compatible cycle ergometer for non-invasive cardiac assessments during exercise

PubMed Central

2012-01-01

Background Magnetic resonance imaging (MRI) is an important tool for cardiac research, and it is frequently used for resting cardiac assessments. However, research into non-pharmacological stress cardiac evaluation is limited. Methods We aimed to design a portable and relatively inexpensive MRI cycle ergometer capable of continuously measuring pedalling workload while patients exercise to maintain target heart rates. Results We constructed and tested an MRI-compatible cycle ergometer for a 1.5 T MRI scanner. Resting and sub-maximal exercise images (at 110 beats per minute) were successfully obtained in 8 healthy adults. Conclusions The MRI-compatible cycle ergometer constructed by our research group enabled cardiac assessments at fixed heart rates, while continuously recording power output by directly measuring pedal force and crank rotation. PMID:22423637

The transfer functions of cardiac tissue during stochastic pacing.

PubMed

de Lange, Enno; Kucera, Jan P

2009-01-01

The restitution properties of cardiac action potential duration (APD) and conduction velocity (CV) are important factors in arrhythmogenesis. They determine alternans, wavebreak, and the patterns of reentrant arrhythmias. We developed a novel approach to characterize restitution using transfer functions. Transfer functions relate an input and an output quantity in terms of gain and phase shift in the complex frequency domain. We derived an analytical expression for the transfer function of interbeat intervals (IBIs) during conduction from one site (input) to another site downstream (output). Transfer functions can be efficiently obtained using a stochastic pacing protocol. Using simulations of conduction and extracellular mapping of strands of neonatal rat ventricular myocytes, we show that transfer functions permit the quantification of APD and CV restitution slopes when it is difficult to measure APD directly. We find that the normally positive CV restitution slope attenuates IBI variations. In contrast, a negative CV restitution slope (induced by decreasing extracellular [K(+)]) amplifies IBI variations with a maximum at the frequency of alternans. Hence, it potentiates alternans and renders conduction unstable, even in the absence of APD restitution. Thus, stochastic pacing and transfer function analysis represent a powerful strategy to evaluate restitution and the stability of conduction.

Post-hypothermic cardiac left ventricular systolic dysfunction after rewarming in an intact pig model

PubMed Central

2010-01-01

Introduction We developed a minimally invasive, closed chest pig model with the main aim to describe hemodynamic function during surface cooling, steady state severe hypothermia (one hour at 25°C) and surface rewarming. Methods Twelve anesthetized juvenile pigs were acutely catheterized for measurement of left ventricular (LV) pressure-volume loops (conductance catheter), cardiac output (Swan-Ganz), and for vena cava inferior occlusion. Eight animals were surface cooled to 25°C, while four animals were kept as normothermic time-matched controls. Results During progressive cooling and steady state severe hypothermia (25°C) cardiac output (CO), stroke volume (SV), mean arterial pressure (MAP), maximal deceleration of pressure in the cardiac cycle (dP/dtmin), indexes of LV contractility (preload recruitable stroke work, PRSW, and maximal acceleration of pressure in the cardiac cycle, dP/dtmax) and LV end diastolic and systolic volumes (EDV and ESV) were significantly reduced. Systemic vascular resistance (SVR), isovolumetric relaxation time (Tau), and oxygen content in arterial and mixed venous blood increased significantly. LV end diastolic pressure (EDP) remained constant. After rewarming all the above mentioned hemodynamic variables that were depressed during 25°C remained reduced, except for CO that returned to pre-hypothermic values due to an increase in heart rate. Likewise, SVR and EDP were significantly reduced after rewarming, while Tau, EDV, ESV and blood oxygen content normalized. Serum levels of cardiac troponin T (TnT) and tumor necrosis factor-alpha (TNF-α) were significantly increased. Conclusions Progressive cooling to 25°C followed by rewarming resulted in a reduced systolic, but not diastolic left ventricular function. The post-hypothermic increase in heart rate and the reduced systemic vascular resistance are interpreted as adaptive measures by the organism to compensate for a hypothermia-induced mild left ventricular cardiac failure. A post

Extracellular volume quantification by dynamic equilibrium cardiac computed tomography in cardiac amyloidosis.

PubMed

Treibel, Thomas A; Bandula, Steve; Fontana, Marianna; White, Steven K; Gilbertson, Janet A; Herrey, Anna S; Gillmore, Julian D; Punwani, Shonit; Hawkins, Philip N; Taylor, Stuart A; Moon, James C

2015-01-01

Cardiac involvement determines outcome in patients with systemic amyloidosis. There is major unmet need for quantification of cardiac amyloid burden, which is currently only met in part through semi-quantitative bone scintigraphy or Cardiovascular Magnetic Resonance (CMR), which measures ECVCMR. Other accessible tests are needed. To develop cardiac computed tomography to diagnose and quantify cardiac amyloidosis by measuring the myocardial Extracellular Volume, ECVCT. Twenty-six patients (21 male, 64 ± 14 years) with a biopsy-proven systemic amyloidosis (ATTR n = 18; AL n = 8) were compared with twenty-seven patients (19 male, 68 ± 8 years) with severe aortic stenosis (AS). All patients had undergone echocardiography, bone scintigraphy, NT-pro-BNP measurement and EQ-CMR. Dynamic Equilibrium CT (DynEQ-CT) was performed using a prospectively gated cardiac scan prior to and after (5 and 15 minutes) a standard Iodixanol (1 ml/kg) bolus to measure ECVCT. ECVCT was compared to the reference ECVCMR and conventional amyloid measures: bone scintigraphy and clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area). ECVCT and ECVCMR results were well correlated (r(2) = 0.85 vs r(2) = 0.74 for 5 and 15 minutes post bolus respectively). ECVCT was higher in amyloidosis than AS (0.54 ± 0.11 vs 0.28 ± 0.04, p<0.001) with no overlap. ECVCT tracked clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area), and bone scintigraphy amyloid burden (p<0.001). Dynamic Equilibrium CT, a 5 minute contrast-enhanced gated cardiac CT, has potential for non-invasive diagnosis and quantification of cardiac amyloidosis. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Extracellular volume quantification by dynamic equilibrium cardiac computed tomography in cardiac amyloidosis

PubMed Central

Treibel, Thomas A.; Bandula, Steve; Fontana, Marianna; White, Steven K.; Gilbertson, Janet A.; Herrey, Anna S.; Gillmore, Julian D.; Punwani, Shonit; Hawkins, Philip N.; Taylor, Stuart A.; Moon, James C.

2015-01-01

Background Cardiac involvement determines outcome in patients with systemic amyloidosis. There is major unmet need for quantification of cardiac amyloid burden, which is currently only met in part through semi-quantitative bone scintigraphy or Cardiovascular Magnetic Resonance (CMR), which measures ECVCMR. Other accessible tests are needed. Objectives To develop cardiac computed tomography to diagnose and quantify cardiac amyloidosis by measuring the myocardial Extracellular Volume, ECVCT. Methods Twenty-six patients (21 male, 64 ± 14 years) with a biopsy-proven systemic amyloidosis (ATTR n = 18; AL n = 8) were compared with twenty-seven patients (19 male, 68 ± 8 years) with severe aortic stenosis (AS). All patients had undergone echocardiography, bone scintigraphy, NT-pro-BNP measurement and EQ-CMR. Dynamic Equilibrium CT (DynEQ-CT) was performed using a prospectively gated cardiac scan prior to and after (5 and 15 minutes) a standard Iodixanol (1 ml/kg) bolus to measure ECVCT. ECVCT was compared to the reference ECVCMR and conventional amyloid measures: bone scintigraphy and clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area). Results ECVCT and ECVCMR results were well correlated (r2 = 0.85 vs r2 = 0.74 for 5 and 15 minutes post bolus respectively). ECVCT was higher in amyloidosis than AS (0.54 ± 0.11 vs 0.28 ± 0.04, p<0.001) with no overlap. ECVCT tracked clinical markers of cardiac amyloid severity (NT-pro-BNP, Troponin, LVEF, LV mass, LA and RA area), and bone scintigraphy amyloid burden (p<0.001). Conclusion Dynamic Equilibrium CT, a 5 minute contrast-enhanced gated cardiac CT, has potential for non-invasive diagnosis and quantification of cardiac amyloidosis. PMID:26209459

Orientation of Myosin Binding Protein C in the Cardiac Muscle Sarcomere Determined by Domain-Specific Immuno-EM

PubMed Central

Lee, Kyounghwan; Harris, Samantha P.; Sadayappan, Sakthivel; Craig, Roger

2014-01-01

Myosin binding protein-C is a thick filament protein of vertebrate striated muscle. The cardiac isoform (cMyBP-C) is essential for normal cardiac function, and mutations in cMyBP-C cause cardiac muscle disease. The rod-shaped molecule is composed primarily of 11 immunoglobulin- or fibronectin-like domains, and is located at 9 sites, 43 nm apart, in each half of the A-band. To understand how cMyBP-C functions, it is important to know its structural organization in the sarcomere, as this will affect its ability to interact with other sarcomeric proteins. Several models have been proposed, in which cMyBP-C wraps around, extends radially from, or runs axially along the thick filament. Our goal was to define cMyBP-C orientation by determining the relative axial positions of different cMyBP-C domains. Immuno-electron microscopy was performed using mouse cardiac myofibrils labeled with antibodies specific to the N- and C-terminal domains and to the middle of cMyBP-C. Antibodies to all regions of the molecule, except the C-terminus, labeled at the same nine axial positions in each half A-band, consistent with a circumferential and/or radial rather than an axial orientation of the bulk of the molecule. The C-terminal antibody stripes were slightly displaced axially, demonstrating an axial orientation of the C-terminal 3 domains, with the C-terminus closer to the M-line. These results, combined with previous studies, suggest that the C-terminal domains of cMyBP-C run along the thick filament surface, while the N-terminus extends towards neighboring thin filaments. This organization provides a structural framework for understanding cMyBP-C’s modulation of cardiac muscle contraction. PMID:25451032

Exercise efficiency of low power output cycling.

PubMed

Reger, M; Peterman, J E; Kram, R; Byrnes, W C

2013-12-01

Exercise efficiency at low power outputs, energetically comparable to daily living activities, can be influenced by homeostatic perturbations (e.g., weight gain/loss). However, an appropriate efficiency calculation for low power outputs used in these studies has not been determined. Fifteen active subjects (seven females, eight males) performed 14, 5-min cycling trials: two types of seated rest (cranks vertical and horizontal), passive (motor-driven) cycling, no-chain cycling, no-load cycling, cycling at low (10, 20, 30, 40 W), and moderate (50, 60, 80, 100, 120 W) power outputs. Mean delta efficiency was 57% for low power outputs compared to 41.3% for moderate power outputs. Means for gross (3.6%) and net (5.7%) efficiencies were low at the lowest power output. At low power outputs, delta and work efficiency values exceeded theoretical values. In conclusion, at low power outputs, none of the common exercise efficiency calculations gave values comparable to theoretical muscle efficiency. However, gross efficiency and the slope and intercept of the metabolic power vs mechanical power output regression provide insights that are still valuable when studying homeostatic perturbations. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Open chest cardiac massage offers no benefit over closed chest compressions in patients with traumatic cardiac arrest.

PubMed

Bradley, Matthew J; Bonds, Brandon W; Chang, Luke; Yang, Shiming; Hu, Peter; Li, Hsiao-Chi; Brenner, Megan L; Scalea, Thomas M; Stein, Deborah M

2016-11-01

Open chest cardiac massage (OCCM) is a commonly performed procedure after traumatic cardiac arrest (TCA). OCCM has been reported to be superior to closed chest compressions (CCC) in animal models and in non-TCA. The purpose of this study is to prospectively compare OCCM versus CCC in TCA using end-tidal carbon dioxide (ETCO2), the criterion standard for determining the effectiveness of chest compressions and detection of return of spontaneous circulation (ROSC), as the surrogate for cardiac output and marker for adequacy of resuscitation. This prospective observational study enrolled patients over a 9-month period directly presenting to a level 1 trauma center after TCA. Continuous high-resolution ETCO2 measurements were collected every 6 seconds for periods of CCC and OCCM, respectively. Patients receiving CCC only were compared with patients receiving CCC followed by OCCM. Student's t tests were used to compare ETCO2 within and between groups. Thirty-three patients were enrolled (16 OCCM, 17 CCC-only). Mean time of CCC before OCCM was 66 seconds. Within the OCCM group, final, peak, mean, and median ETCO2 levels significantly increased when comparing the initial CCC period to the OCCM interval. Using a time-matched comparison, significant increases were observed in the final and peak but not mean and median values when comparing the first minute of CCC to the remaining time in the CCC-only group. However, when periods of OCCM were compared with equivalent periods of CCC-only, there were no differences in the initial, final, peak, mean, or median ETCO2 values. Correspondingly, no difference in rates of ROSC was observed between groups (OCCM 23.5% vs. CCC 38.9%; p = 0.53). Although we could not control for confounders, we found no significant improvement in ETCO2 or ROSC with OCCM. With newer endovascular techniques for aortic occlusion, thoracotomy solely for performing OCCM provides no benefit over CCC. Therapeutic study, level III.

Ivabradine and metoprolol differentially affect cardiac glucose metabolism despite similar heart rate reduction in a mouse model of dyslipidemia.

PubMed

Vaillant, Fanny; Lauzier, Benjamin; Ruiz, Matthieu; Shi, Yanfen; Lachance, Dominic; Rivard, Marie-Eve; Bolduc, Virginie; Thorin, Eric; Tardif, Jean-Claude; Des Rosiers, Christine

2016-10-01

While heart rate reduction (HRR) is a target for the management of patients with heart disease, contradictory results were reported using ivabradine, which selectively inhibits the pacemaker I f current, vs. β-blockers like metoprolol. This study aimed at testing whether similar HRR with ivabradine vs. metoprolol differentially modulates cardiac energy substrate metabolism, a factor determinant for cardiac function, in a mouse model of dyslipidemia (hApoB +/+ ;LDLR -/- ). Following a longitudinal study design, we used 3- and 6-mo-old mice, untreated or treated for 3 mo with ivabradine or metoprolol. Cardiac function was evaluated in vivo and ex vivo in working hearts perfused with 13 C-labeled substrates to assess substrate fluxes through energy metabolic pathways. Compared with 3-mo-old, 6-mo-old dyslipidemic mice had similar cardiac hemodynamics in vivo but impaired (P < 0.001) contractile function (aortic flow: -45%; cardiac output: -34%; stroke volume: -35%) and glycolysis (-24%) ex vivo. Despite inducing a similar 10% HRR, ivabradine-treated hearts displayed significantly higher stroke volume values and glycolysis vs. their metoprolol-treated counterparts ex vivo, values for the ivabradine group being often not significantly different from 3-mo-old mice. Further analyses highlighted additional significant cardiac alterations with disease progression, namely in the total tissue level of proteins modified by O-linked N-acetylglucosamine (O-GlcNAc), whose formation is governed by glucose metabolism via the hexosamine biosynthetic pathway, which showed a similar pattern with ivabradine vs. metoprolol treatment. Collectively, our results emphasize the implication of alterations in cardiac glucose metabolism and signaling linked to disease progression in our mouse model. Despite similar HRR, ivabradine, but not metoprolol, preserved cardiac function and glucose metabolism during disease progression. Copyright © 2016 the American Physiological Society.

Network interactions within the canine intrinsic cardiac nervous system: implications for reflex control of regional cardiac function

PubMed Central

Beaumont, Eric; Salavatian, Siamak; Southerland, E Marie; Vinet, Alain; Jacquemet, Vincent; Armour, J Andrew; Ardell, Jeffrey L

2013-01-01

The aims of the study were to determine how aggregates of intrinsic cardiac (IC) neurons transduce the cardiovascular milieu versus responding to changes in central neuronal drive and to determine IC network interactions subsequent to induced neural imbalances in the genesis of atrial fibrillation (AF). Activity from multiple IC neurons in the right atrial ganglionated plexus was recorded in eight anaesthetized canines using a 16-channel linear microelectrode array. Induced changes in IC neuronal activity were evaluated in response to: (1) focal cardiac mechanical distortion; (2) electrical activation of cervical vagi or stellate ganglia; (3) occlusion of the inferior vena cava or thoracic aorta; (4) transient ventricular ischaemia, and (5) neurally induced AF. Low level activity (ranging from 0 to 2.7 Hz) generated by 92 neurons was identified in basal states, activities that displayed functional interconnectivity. The majority (56%) of IC neurons so identified received indirect central inputs (vagus alone: 25%; stellate ganglion alone: 27%; both: 48%). Fifty per cent transduced the cardiac milieu responding to multimodal stressors applied to the great vessels or heart. Fifty per cent of IC neurons exhibited cardiac cycle periodicity, with activity occurring primarily in late diastole into isovolumetric contraction. Cardiac-related activity in IC neurons was primarily related to direct cardiac mechano-sensory inputs and indirect autonomic efferent inputs. In response to mediastinal nerve stimulation, most IC neurons became excessively activated; such network behaviour preceded and persisted throughout AF. It was concluded that stochastic interactions occur among IC local circuit neuronal populations in the control of regional cardiac function. Modulation of IC local circuit neuronal recruitment may represent a novel approach for the treatment of cardiac disease, including atrial arrhythmias. PMID:23818689

Cardiac perioperative complications in noncardiac surgery.

PubMed

Radovanović, Dragana; Kolak, Radmila; Stokić, Aleksandar; Radovanović, Zoran; Jovanović, Gordana

2008-01-01

Anesthesiologists are confronted with an increasing population of patients undergoing noncardiac surgery who are at risk for cardiac complications in the perioperative period. Perioperative cardiac complications are responsible for significant mortality and morbidity. The aim of the present study was to determine the incidence of perioperative (operative and postoperative) cardiac complications and correlations between the incidence of perioperative cardiac complications and type of surgical procedure, age, presence of concurrent deseases. A total of 100 patients with cardiac diseases undergoing noncardiac surgery were included in the prospective study (Group A 50 patients undergoing intraperitoneal surgery and Group B 50 patients undergoing breast and thyroid surgery). The patients were followed up during the perioperative period and after surgery until leaving hospital to assess the occurrence of cardiac events. Cardiac complications (systemic arterial hypertension, systemic arterial hypotension, abnormalities of cardiac conduction and cardiac rhythm, perioperative myocardial ischemia and acute myocardial infarction) occurred in 64% of the patients. One of the 100 patients (1%) had postoperative myocardial infarction which was fatal. Systemic arterial hypertension occured in 57% of patients intraoperatively and 33% postoperatively, abnormalities of cardiac rhythm in 31% of patients intraoperatively and 17% postoperatively, perioperative myocardial ischemia in 23% of patients intraoperatively and 11% of postoperatively. The most often cardiac complications were systemic arterial hypertension, abnormalities of cardiac rhythm and perioperative mvocardial ischemia. Factors independently associated with the incidence of cardiac complications included the type of surgical procedure, advanced age, duration of anaesthesia and surgery, abnormal preoperative electrocardiogram, abnormal preoperative chest radiography and diabetes.

Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig.

PubMed

Beaumont, Eric; Wright, Gary L; Southerland, Elizabeth M; Li, Ying; Chui, Ray; KenKnight, Bruce H; Armour, J Andrew; Ardell, Jeffrey L

2016-05-15

Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15-20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling. Copyright © 2016 the American Physiological Society.

Right Ventricular Volumes and Systolic Function by Cardiac Magnetic Resonance and the Impact of Sex, Age, and Obesity in a Longitudinally Followed Cohort Free of Pulmonary and Cardiovascular Disease: The Framingham Heart Study.

PubMed

Foppa, Murilo; Arora, Garima; Gona, Philimon; Ashrafi, Arman; Salton, Carol J; Yeon, Susan B; Blease, Susan J; Levy, Daniel; O'Donnell, Christopher J; Manning, Warren J; Chuang, Michael L

2016-03-01

Cardiac magnetic resonance is uniquely well suited for noninvasive imaging of the right ventricle. We sought to define normal cardiac magnetic resonance reference values and to identify the main determinants of right ventricular (RV) volumes and systolic function using a modern imaging sequence in a community-dwelling, longitudinally followed cohort free of clinical cardiovascular and pulmonary disease. The Framingham Heart Study Offspring cohort has been followed since 1971. We scanned 1794 Offspring cohort members using steady-state free precession cardiac magnetic resonance and identified a reference group of 1336 adults (64±9 years, 576 men) free of prevalent cardiovascular and pulmonary disease. RV trabeculations and papillary muscles were considered cavity volume. Men had greater RV volumes and cardiac output before and after indexation to body size (all P<0.001). Women had higher RV ejection fraction than men (68±6% versus 64±7%; P<0.0001). RV volumes and cardiac output decreased with advancing age. There was an increase in raw and height-indexed RV measurements with increasing body mass index, but this trend was weakly inverted after indexation of RV volumes to body surface area. Sex, age, height, body mass index, and heart rate account for most of the variability in RV volumes and function in this community-dwelling population. We report sex-specific normative values for RV measurements among principally middle-aged and older adults. RV ejection fraction is greater in women. RV volumes increase with body size, are greater in men, and are smaller in older people. Body surface area seems to be appropriate for indexation of cardiac magnetic resonance-derived RV volumes. © 2016 American Heart Association, Inc.

Determinants of distance walked during the six-minute walk test in patients undergoing cardiac surgery at hospital discharge

PubMed Central

2014-01-01

Introduction The aim of this study was to identify the determinants of distance walked in six-minute walk test (6MWD) in patients undergoing cardiac surgery at hospital discharge. Methods The assessment was performed preoperatively and at discharge. Data from patient records were collected and measurement of the Functional Independence Measure (FIM) and the Nottingham Health Profile (NHP) were performed. The six-minute walk test (6MWT) was performed at discharge. Patients undergoing elective cardiac surgery, coronary artery bypass grafting or valve replacement were eligible. Patients older than 75 years who presented arrhythmia during the protocol, with psychiatric disorders, muscular or neurological disorders were excluded from the study. Results Sixty patients (44.26% male, mean age 51.53 ± 13 years) were assessed. In multivariate analysis the following variables were selected: type of surgery (P = 0.001), duration of cardiopulmonary bypass (CPB) (P = 0.001), Functional Independence Measure - FIM (0.004) and body mass index - BMI (0.007) with r = 0.91 and r2 = 0.83 with P < 0.001. The equation derived from multivariate analysis: 6MWD = Surgery (89.42) + CPB (1.60) + MIF (2.79 ) - BMI (7.53) - 127.90. Conclusion In this study, the determinants of 6MWD in patients undergoing cardiac surgery were: the type of surgery, CPB time, functional capacity and body mass index. PMID:24885130

Endothelial, cardiac muscle and skeletal muscle exhibit different viscous and elastic properties as determined by atomic force microscopy

NASA Technical Reports Server (NTRS)

Mathur, A. B.; Collinsworth, A. M.; Reichert, W. M.; Kraus, W. E.; Truskey, G. A.

2001-01-01

This study evaluated the hypothesis that, due to functional and structural differences, the apparent elastic modulus and viscous behavior of cardiac and skeletal muscle and vascular endothelium would differ. To accurately determine the elastic modulus, the contribution of probe velocity, indentation depth, and the assumed shape of the probe were examined. Hysteresis was observed at high indentation velocities arising from viscous effects. Irreversible deformation was not observed for endothelial cells and hysteresis was negligible below 1 microm/s. For skeletal muscle and cardiac muscle cells, hysteresis was negligible below 0.25 microm/s. Viscous dissipation for endothelial and cardiac muscle cells was higher than for skeletal muscle cells. The calculated elastic modulus was most sensitive to the assumed probe geometry for the first 60 nm of indentation for the three cell types. Modeling the probe as a blunt cone-spherical cap resulted in variation in elastic modulus with indentation depth that was less than that calculated by treating the probe as a conical tip. Substrate contributions were negligible since the elastic modulus reached a steady value for indentations above 60 nm and the probe never indented more than 10% of the cell thickness. Cardiac cells were the stiffest (100.3+/-10.7 kPa), the skeletal muscle cells were intermediate (24.7+/-3.5 kPa), and the endothelial cells were the softest with a range of elastic moduli (1.4+/-0.1 to 6.8+/-0.4 kPa) depending on the location of the cell surface tested. Cardiac and skeletal muscle exhibited nonlinear elastic behavior. These passive mechanical properties are generally consistent with the function of these different cell types.

Cardiac catheterization

MedlinePlus

Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

Pulse transit time measured by photoplethysmography improves the accuracy of heart rate as a surrogate measure of cardiac output, stroke volume and oxygen uptake in response to graded exercise.

PubMed

Pollonini, L; Padhye, N S; Re, R; Torricelli, A; Simpson, R J; Dacso, C C

2015-05-01

Heart rate (HR) is a valuable and widespread measure for physical training programs, although its description of conditioning is limited to the cardiac response to exercise. More comprehensive measures of exercise adaptation include cardiac output (Q̇), stroke volume (SV) and oxygen uptake (V̇O2), but these physiological parameters can be measured only with cumbersome equipment installed in clinical settings. In this work, we explore the ability of pulse transit time (PTT) to represent a valuable pairing with HR for indirectly estimating Q̇, SV and V̇O2 non-invasively. PTT was measured as the time interval between the peak of the electrocardiographic (ECG) R-wave and the onset of the photoplethysmography (PPG) waveform at the periphery (i.e. fingertip) with a portable sensor. Fifteen healthy young subjects underwent a graded incremental cycling protocol after which HR and PTT were correlated with Q̇, SV and V̇O2 using linear mixed models. The addition of PTT significantly improved the modeling of Q̇, SV and V̇O2 at the individual level ([Formula: see text] for SV, 0.548 for Q̇, and 0.771 for V̇O2) compared to predictive models based solely on HR ([Formula: see text] for SV, 0.503 for Q̇, and 0.745 for V̇O2). While challenges in sensitivity and artifact rejection exist, combining PTT with HR holds potential for development of novel wearable sensors that provide exercise assessment largely superior to HR monitors.

Cardiac surgery productivity and throughput improvements.

PubMed

Lehtonen, Juha-Matti; Kujala, Jaakko; Kouri, Juhani; Hippeläinen, Mikko

2007-01-01

The high variability in cardiac surgery length--is one of the main challenges for staff managing productivity. This study aims to evaluate the impact of six interventions on open-heart surgery operating theatre productivity. A discrete operating theatre event simulation model with empirical operation time input data from 2603 patients is used to evaluate the effect that these process interventions have on the surgery output and overtime work. A linear regression model was used to get operation time forecasts for surgery scheduling while it also could be used to explain operation time. A forecasting model based on the linear regression of variables available before the surgery explains 46 per cent operating time variance. The main factors influencing operation length were type of operation, redoing the operation and the head surgeon. Reduction of changeover time between surgeries by inducing anaesthesia outside an operating theatre and by reducing slack time at the end of day after a second surgery have the strongest effects on surgery output and productivity. A more accurate operation time forecast did not have any effect on output, although improved operation time forecast did decrease overtime work. A reduction in the operation time itself is not studied in this article. However, the forecasting model can also be applied to discover which factors are most significant in explaining variation in the length of open-heart surgery. The challenge in scheduling two open-heart surgeries in one day can be partly resolved by increasing the length of the day, decreasing the time between two surgeries or by improving patient scheduling procedures so that two short surgeries can be paired. A linear regression model is created in the paper to increase the accuracy of operation time forecasting and to identify factors that have the most influence on operation time. A simulation model is used to analyse the impact of improved surgical length forecasting and five selected process

Sudden Cardiac Arrest during Participation in Competitive Sports.

PubMed

Landry, Cameron H; Allan, Katherine S; Connelly, Kim A; Cunningham, Kris; Morrison, Laurie J; Dorian, Paul

2017-11-16

The incidence of sudden cardiac arrest during participation in sports activities remains unknown. Preparticipation screening programs aimed at preventing sudden cardiac arrest during sports activities are thought to be able to identify at-risk athletes; however, the efficacy of these programs remains controversial. We sought to identify all sudden cardiac arrests that occurred during participation in sports activities within a specific region of Canada and to determine their causes. In this retrospective study, we used the Rescu Epistry cardiac arrest database (which contains records of every cardiac arrest attended by paramedics in the network region) to identify all out-of-hospital cardiac arrests that occurred from 2009 through 2014 in persons 12 to 45 years of age during participation in a sport. Cases were adjudicated as sudden cardiac arrest (i.e., having a cardiac cause) or as an event resulting from a noncardiac cause, on the basis of records from multiple sources, including ambulance call reports, autopsy reports, in-hospital data, and records of direct interviews with patients or family members. Over the course of 18.5 million person-years of observation, 74 sudden cardiac arrests occurred during participation in a sport; of these, 16 occurred during competitive sports and 58 occurred during noncompetitive sports. The incidence of sudden cardiac arrest during competitive sports was 0.76 cases per 100,000 athlete-years, with 43.8% of the athletes surviving until they were discharged from the hospital. Among the competitive athletes, two deaths were attributed to hypertrophic cardiomyopathy and none to arrhythmogenic right ventricular cardiomyopathy. Three cases of sudden cardiac arrest that occurred during participation in competitive sports were determined to have been potentially identifiable if the athletes had undergone preparticipation screening. In our study involving persons who had out-of-hospital cardiac arrest, the incidence of sudden cardiac

[Remote results of plastic operations on the tricuspid valve in patients with cardiac insufficiency at terminal stage].

PubMed

Habriielian, A V; Smorzhevs'kyĭ, V I; Onishchenko, V F; Beleĭovych, V V; Topchu, Ie I; Domans'kyĭ, T M; Myroniuk, O I

2011-07-01

Comparative analysis of the results of plastic operations performance on a tricuspid valve (TV) in patients, suffering cardiac insufficiency in terminal stage, was conducted. In late postoperative period the indices of intracardial hemodynamics (cardiac output fraction, regurgitation on TV) and clinical features (severity of symptoms, quality of life) after plastic operations, using a support ring, have differed significantly from those after performance of a sutured plasty. The valve function during five years was secured in 91.1% of patients.

Cardiac differentiation of cardiosphere-derived cells in scaffolds mimicking morphology of the cardiac extracellular matrix.

PubMed

Xu, Yanyi; Patnaik, Sourav; Guo, Xiaolei; Li, Zhenqing; Lo, Wilson; Butler, Ryan; Claude, Andrew; Liu, Zhenguo; Zhang, Ge; Liao, Jun; Anderson, Peter M; Guan, Jianjun

2014-08-01

Stem cell therapy has the potential to regenerate heart tissue after myocardial infarction (MI). The regeneration is dependent upon cardiac differentiation of the delivered stem cells. We hypothesized that timing of the stem cell delivery determines the extent of cardiac differentiation as cell differentiation is dependent on matrix properties such as biomechanics, structure and morphology, and these properties in cardiac extracellular matrix (ECM) continuously vary with time after MI. In order to elucidate the relationship between ECM properties and cardiac differentiation, we created an in vitro model based on ECM-mimicking fibers and a type of cardiac progenitor cell, cardiosphere-derived cells (CDCs). A simultaneous fiber electrospinning and cell electrospraying technique was utilized to fabricate constructs. By blending a highly soft hydrogel with a relatively stiff polyurethane and modulating fabrication parameters, tissue constructs with similar cell adhesion property but different global modulus, single fiber modulus, fiber density and fiber alignment were achieved. The CDCs remained alive within the constructs during a 1week culture period. CDC cardiac differentiation was dependent on the scaffold modulus, fiber volume fraction and fiber alignment. Two constructs with relatively low scaffold modulus, ∼50-60kPa, most significantly directed the CDC differentiation into mature cardiomyocytes as evidenced by gene expressions of cardiac troponin T (cTnT), calcium channel (CACNA1c) and cardiac myosin heavy chain (MYH6), and protein expressions of cardiac troponin I (cTnI) and connexin 43 (CX43). Of these two low-modulus constructs, the extent of differentiation was greater for lower fiber alignment and higher fiber volume fraction. These results suggest that cardiac ECM properties may have an effect on cardiac differentiation of delivered stem cells. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Determination of cardiac size following space missions of different durations: the second manned Skylab mission.

PubMed

Nicogossian, A; Hoffler, G W; Johnson, R L; Gowen, R J

1976-04-01

A simple method to estimate cardiac size from single frontal plane chest roentgenograms has been described. Pre- and postflight chest X-rays from Apollo 17, and Skylab 2 and 3 have been analyzed for changes in the cardiac silhouette size. The data obtained from the computed cardiothoracic areal ratios compared well with the clinical cardiothoracic diametral ratios (r = .86). Though an overall postflight decrease in cardiac size is evident, the mean difference was not statistically significant (n = 8). The individual decreases in the cardiac silhouette size postflight are thought to be due to decrements in intracardiac chamber volumes rather than in myocardial muscle mass.

Determination of cardiac size following space missions of different durations - The second manned Skylab mission

NASA Technical Reports Server (NTRS)

Nicogossian, A.; Hoffler, G. W.; Johnson, R. L.; Gowen, R. J.

1976-01-01

A simple method to estimate cardiac size from single frontal plane chest roentgenograms has been described. Pre- and postflight chest X-rays from Apollo 17, and Skylab 2 and 3 have been analyzed for changes in the cardiac silhouette size. The data obtained from the computed cardiothoracic areal ratios compared well with the clinical cardiothoracic diametral ratios (r = .86). Though an overall postflight decrease in cardiac size is evident, the mean difference was not statistically significant (n = 8). The individual decreases in the cardiac silhouette size postflight are thought to be due to decrements in intracardiac chamber volumes rather than in myocardial muscle mass.

Cardiac-specific overexpression of aldehyde dehydrogenase 2 exacerbates cardiac remodeling in response to pressure overload.

PubMed

Dassanayaka, Sujith; Zheng, Yuting; Gibb, Andrew A; Cummins, Timothy D; McNally, Lindsey A; Brittian, Kenneth R; Jagatheesan, Ganapathy; Audam, Timothy N; Long, Bethany W; Brainard, Robert E; Jones, Steven P; Hill, Bradford G

2018-06-01

Pathological cardiac remodeling during heart failure is associated with higher levels of lipid peroxidation products and lower abundance of several aldehyde detoxification enzymes, including aldehyde dehydrogenase 2 (ALDH2). An emerging idea that could explain these findings concerns the role of electrophilic species in redox signaling, which may be important for adaptive responses to stress or injury. The purpose of this study was to determine whether genetically increasing ALDH2 activity affects pressure overload-induced cardiac dysfunction. Mice subjected to transverse aortic constriction (TAC) for 12 weeks developed myocardial hypertrophy and cardiac dysfunction, which were associated with diminished ALDH2 expression and activity. Cardiac-specific expression of the human ALDH2 gene in mice augmented myocardial ALDH2 activity but did not improve cardiac function in response to pressure overload. After 12 weeks of TAC, ALDH2 transgenic mice had larger hearts than their wild-type littermates and lower capillary density. These findings show that overexpression of ALDH2 augments the hypertrophic response to pressure overload and imply that downregulation of ALDH2 may be an adaptive response to certain forms of cardiac pathology. Copyright © 2018. Published by Elsevier B.V.

The frequency of anesthesia-related cardiac arrests in patients with congenital heart disease undergoing cardiac surgery.

PubMed

Odegard, Kirsten C; DiNardo, James A; Kussman, Barry D; Shukla, Avinash; Harrington, James; Casta, Al; McGowan, Francis X; Hickey, Paul R; Bacha, Emile A; Thiagarajan, Ravi R; Laussen, Peter C

2007-08-01

The frequency of anesthesia-related cardiac arrests during pediatric anesthesia has been reported between 1.4 and 4.6 per 10,000 anesthetics. ASA physical status >III and younger age are risk factors. Patients with congenital cardiac disease may also be at increased risk. Therefore, in this study, we evaluated the frequency of cardiac arrest in patients with congenital heart disease undergoing cardiac surgery at a large pediatric tertiary referral center. Using an established data registry, all cardiac arrests from January 2000 through December 2005 occurring in the cardiac operating rooms were reviewed. A cardiac arrest was defined as any event requiring external or internal chest compressions, with or without direct cardioversion. Events determined to be anesthesia-related were classified as likely related or possibly related. There were 41 cardiac arrests in 40 patients (median age, 2.9 mo; range, 2 days to 23 yr) during 5213 anesthetics over the time period, for an overall frequency of 0.79%; 78% were open procedures requiring cardiopulmonary bypass and 22% closed procedures not requiring cardiopulmonary bypass. Eleven cardiac arrests (26.8%) were classified as either likely (n = 6) or possibly related (n = 5) to anesthesia, (21.1 per 10,000 anesthetics) but with no mortality; 30 were categorized as procedure-related. The incidence of anesthesia-related and procedure-related cardiac arrests was highest in neonates (P < 0.001). There was no association with year of event or experience of the anesthesiologist. The frequency of anesthesia-related cardiac arrest in patients undergoing cardiac surgery is increased, but is not associated with an increase in mortality. Neonates and infants are at higher risk. Careful preparation and anticipation is important to ensure timely and effective resuscitation.

Direct recording of cardiac output- and venous return-curves in the dog heart-lung preparation for a graphical analysis of the effects of cardioactive drugs.

PubMed

Ishikawa, N; Taki, K; Hojo, Y; Hagino, Y; Shigei, T

1978-09-01

The dog heart-lung preparations were prepared. The "equilibrium point", which could be defined as the point at which the cardiac output (CO)-curve and the venous return (VR)-curve crossed, when the CO and VR were plotted against the right atrial pressure, was recorded directly by utilizing an X-Y recorder. The CO-curve was obtained, as a locus of the equilibrium point, by raising and lowering the level of blood in the venous reservoir (competence test). The meaning of the procedure was shown to increase or decrease the mean systemic pressure, and to cause the corresponding parallel shift in the VR-curve. The VR-curve was obtained by changing myocardial contractility. When heart failure was induced by pentobarbital or by chloroform, the equilibrium point shifted downwards to the right, depicting the VR-curve. During development of the failure, the slopes of CO-curves decreased gradually. Effects of cinobufagin and norepinephrine were also analyzed. Utilization of the X-Y recorder enabled us to settle the uniform experimental conditions more easily, and to follow the effects of drugs continuously on a diagram equating the CO- and VR-curves (Gyton's scheme).

The Utility of Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Sarcoidosis.

PubMed

Stanton, Kelly M; Ganigara, Madhusudan; Corte, Peter; Celermajer, David S; McGuire, Mark A; Torzillo, Paul J; Corte, Tamera J; Puranik, Rajesh

2017-11-01

Autopsy reports suggest that cardiac sarcoidosis occurs in 20 to 25% of patients with pulmonary sarcoidosis, yet the clinical ante-mortem diagnosis is made in only 5% of cases. Current diagnostic algorithms are complex and lack sensitivity. Cardiac Magnetic Resonance imaging (CMR) provides an opportunity to detect myocardial involvement in sarcoidosis. The aim of this study is to determine the prevalence and clinical significance of late gadolinium enhancement (LGE) on CMR in patients with sarcoidosis. Consecutive patients with biopsy-proven sarcoidosis undergoing CMR were retrospectively evaluated for cardiac sarcoidosis. Medical records were correlated with CMR. Forty-six patients were evaluated. Late gadolinium enhancement was present in 22%, indicating myocardial involvement, and 70% had corresponding hyper-intense T2 signal indicating active inflammation. Late gadolinium enhancement was 18%+/-9.7% of overall left ventricular (LV) mass and most commonly located in the basal to mid septum. There was no association between LGE and cardiovascular symptoms or pulmonary stage. Eighty per cent of patients with LGE did not fulfill conventional diagnostic criteria for cardiac sarcoidosis. However, LGE was associated with clinically significant arrhythmia (p<0.01) and a lower LVEF (p=0.04). Using CMR, we identified a higher prevalence of cardiac sarcoidosis than previously reported clinical studies, a prevalence which is more consistent with autopsy data. The presence of LGE was highly correlated with clinically significant arrhythmias and lower LVEF. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.

Myocardial protection during minimally invasive cardiac surgery through right mini-thoracotomy.

PubMed

De Palo, Micaela; Guida, Pietro; Mastro, Florinda; Nanna, Daniela; Quagliara, Teresa A P; Rociola, Ruggiero; Lionetti, Giosuè; Paparella, Domenico

2017-04-01

Myocardial damage is an independent predictor of adverse outcome following cardiac surgery and myocardial protection is one of the key factors to achieve successful outcomes. Cardioplegia with Custodiol is currently the most used cardioplegia during minimally invasive cardiac surgery (MICS). Different randomized controlled trials compared blood and Custodiol cardioplegia in the context of traditional cardiac surgery. No data are available for MICS. The aim of this study was to compare the efficacy of cold blood versus Custodiol cardioplegia during MICS. We retrospectively evaluated 90 patients undergoing MICS through a right mini-thoracotomy in a three-year period. Myocardial protection was performed using cold blood (44 patients, CBC group) or Custodiol (46 patients, Custodiol group) cardioplegia, based on surgeon preference and complexity of surgery. The primary outcomes were post-operative cardiac troponin I (cTnI) and creatine kinase MB (CKMB) serum release and the incidence of Low Cardiac Output Syndrome (LCOS). Aortic cross-clamp and cardiopulmonary bypass times were higher in the Custodiol group. No difference was observed in myocardial injury enzyme release (peak cTnI value was 18±46 ng/ml in CBC and 21±37 ng/ml in Custodiol; p=0.245). No differences were observed for mortality, LCOS, atrial or ventricular arrhythmias onset, transfusions, mechanical ventilation time duration, intensive care unit and total hospital stay. Custodiol and cold blood cardioplegic solutions seem to assure similar myocardial protection in patients undergoing cardiac surgery through a right mini-thoracotomy approach.

Association between patient activity and long-term cardiac death in patients with implantable cardioverter-defibrillators and cardiac resynchronization therapy defibrillators.

PubMed

Zhao, Shuang; Chen, Keping; Su, Yangang; Hua, Wei; Chen, Silin; Liang, Zhaoguang; Xu, Wei; Dai, Yan; Liu, Zhimin; Fan, Xiaohan; Hou, Cuihong; Zhang, Shu

2017-05-01

Background Patient activity (PA) has been demonstrated to predict all-cause mortality. However, the association between PA and cardiac death is unclear. Aims The aims of this study were to determine whether PA can predict cardiac death and what is the cut-off of PA to discriminate cardiac death, as well as the mechanism underlying the relationship between PA and survival in patients with home monitoring. Methods This study retrospectively analysed clinical and implantable cardioverter-defibrillator/cardiac resynchronization therapy defibrillator device data in 845 patients. Data regarding PA and PP variability during the first 30-60 days of home monitoring were collected, and mean values were calculated. The primary endpoint was cardiac death, and the secondary endpoint was all-cause mortality. Results The mean PA percentage was 11 ± 5.8%. Based on receiver operating characteristic curve analysis, we determined that a PA cut-off value of 7.84% (113 min) can predict cardiac death. During a mean follow-up period of 31.1 ± 12.9 months (ranging from three to 60 months), PA ≤ 7.84% was associated with increased risks of cardiac death in an unadjusted analysis; after adjusting in a multivariate Cox model, the relationship remained significant between PA≤7.84% and cardiac death (hazard ratio = 3.644, 95% confidence interval = 2.424-5.477, p < 0.001). Moreover, a significant correlation was observed between PA and PP variability ( r = 0.601, p < 0.001). Conclusions A baseline PA ≤ 7.84% was associated with a higher risk of cardiac death in patients who have survived more than three months after implantable cardioverter-defibrillator/cardiac resynchronization therapy defibrillator implantation. PA had a sizable effect on heart rate variability, reflecting autonomic function.

Competition model for aperiodic stochastic resonance in a Fitzhugh-Nagumo model of cardiac sensory neurons.

PubMed

Kember, G C; Fenton, G A; Armour, J A; Kalyaniwalla, N

2001-04-01

Regional cardiac control depends upon feedback of the status of the heart from afferent neurons responding to chemical and mechanical stimuli as transduced by an array of sensory neurites. Emerging experimental evidence shows that neural control in the heart may be partially exerted using subthreshold inputs that are amplified by noisy mechanical fluctuations. This amplification is known as aperiodic stochastic resonance (ASR). Neural control in the noisy, subthreshold regime is difficult to see since there is a near absence of any correlation between input and the output, the latter being the average firing (spiking) rate of the neuron. This lack of correlation is unresolved by traditional energy models of ASR since these models are unsuitable for identifying "cause and effect" between such inputs and outputs. In this paper, the "competition between averages" model is used to determine what portion of a noisy, subthreshold input is responsible, on average, for the output of sensory neurons as represented by the Fitzhugh-Nagumo equations. A physiologically relevant conclusion of this analysis is that a nearly constant amount of input is responsible for a spike, on average, and this amount is approximately independent of the firing rate. Hence, correlation measures are generally reduced as the firing rate is lowered even though neural control under this model is actually unaffected.

FET-biosensor for cardiac troponin biomarker

NASA Astrophysics Data System (ADS)

Arshad, Mohd Khairuddin Md; Faris Mohamad Fathil, Mohamad; Hashim, Uda

2017-11-01

Acute myocardial infarction or myocardial infarction (MI) is a major health problem, due to diminished flow of blood to the heart, leads to higher rates of mortality and morbidity. The most specific markers for cardiac injury are cardiac troponin I (cTnI) and cardiac troponin T (cTnT) which have been considered as `gold standard'. Due to higher specificity, determination of the level of cardiac troponins became a predominant indicator for MI. Currently, field-effect transistor (FET)-based biosensors have been main interest to be implemented in portable sensors with the ultimate application in point-of-care testing (POCT). In this paper, we review on the FET-based biosensor based on its principle of operation, integration with nanomaterial, surface functionalization as well as immobilization, and the introduction of additional gate (for ambipolar conduction) on the device architecture for the detection of cardiac troponin I (cTnI) biomarker.

Mitochondrial oxidative stress and cardiac ageing.

PubMed

Martín-Fernández, Beatriz; Gredilla, Ricardo

According with different international organizations, cardiovascular diseases are becoming the first cause of death in western countries. Although exposure to different risk factors, particularly those related to lifestyle, contribute to the etiopathogenesis of cardiac disorders, the increase in average lifespan and aging are considered major determinants of cardiac diseases events. Mitochondria and oxidative stress have been pointed out as relevant factors both in heart aging and in the development of cardiac diseases such as heart failure, cardiac hypertrophy and diabetic cardiomyopathy. During aging, cellular processes related with mitochondrial function, such as bioenergetics, apoptosis and inflammation are altered leading to cardiac dysfunction. Increasing our knowledge about the mitochondrial mechanisms related with the aging process, will provide new strategies in order to improve this process, particularly the cardiovascular ones. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

Proteostasis in cardiac health and disease.

PubMed

Henning, Robert H; Brundel, Bianca J J M

2017-11-01

The incidence and prevalence of cardiac diseases, which are the main cause of death worldwide, are likely to increase because of population ageing. Prevailing theories about the mechanisms of ageing feature the gradual derailment of cellular protein homeostasis (proteostasis) and loss of protein quality control as central factors. In the heart, loss of protein patency, owing to flaws in genetically-determined design or because of environmentally-induced 'wear and tear', can overwhelm protein quality control, thereby triggering derailment of proteostasis and contributing to cardiac ageing. Failure of protein quality control involves impairment of chaperones, ubiquitin-proteosomal systems, autophagy, and loss of sarcomeric and cytoskeletal proteins, all of which relate to induction of cardiomyocyte senescence. Targeting protein quality control to maintain cardiac proteostasis offers a novel therapeutic strategy to promote cardiac health and combat cardiac disease. Currently marketed drugs are available to explore this concept in the clinical setting.

Cardiac Pressure Changes with Venous Gas Embolism and Decompression

DTIC Science & Technology

1994-04-01

inferior vena cava via the left femoral vein for venous access. Airway pressure was measured from a connector at the proximal end of the endotracheal...Hartley), mount- ed in a 7-9 m acrylic cuff was surgically placed around the inferior vena cava via laparotomy, approximately 1-2 cm above the renal...pressure and decreasing cardiac output which in return may cause the left atrial pressure to fall below that of the right atrium . Recent studies have

Managing complex, high-output, enterocutaneous fistulas: a case study.

PubMed

Hahler, Barbara; Schassberger, Debra; Novakovic, Rachel; Lang, Stephanie

2009-10-15

Gastrointestinal (GI) fistulas are an uncommon but serious complication. Following diagnosis, management strategies may have to be adapted frequently to address changes in fistula output, surrounding skin or wound condition, overall patient clinical and nutritional status, mobility level, and body contours. Following a motor vehicle accident, a 49-year-old man with a body mass index of 36.8 and a history of multiple previous surgeries, including gastric bypass, experienced excessive output from a fistula within a large open abdominal wound measuring 45 cm x 40 cm x 5 cm. Abdominal creases and the need to protect a split-thickness skin graft of the wound surrounding his fistula complicated wound management. During his prolonged 4-month hospital stay, the patient underwent several surgical procedures, repeated wound debridement, and various nutritional support interventions; a wide variety of wound and fistula management systems were utilized. One year after the initial trauma, the fistula was surgically closed. One week later, the patient died from a cardiac event. This case study confirms that GI fistulas increase costs of care and hospital length of stay and require the experience and expertise of a wide array of patient support staff members and clinicians.

Determining a human cardiac pacemaker using fuzzy logic

NASA Astrophysics Data System (ADS)

Varnavsky, A. N.; Antonenco, A. V.

2017-01-01

The paper presents a possibility of estimating a human cardiac pacemaker using combined application of nonlinear integral transformation and fuzzy logic, which allows carrying out the analysis in the real-time mode. The system of fuzzy logical conclusion is proposed, membership functions and rules of fuzzy products are defined. It was shown that the ratio of the value of a truth degree of the winning rule condition to the value of a truth degree of any other rule condition is at least 3.

Selectivity verification of cardiac troponin monoclonal antibodies for cardiac troponin detection by using conventional ELISA

NASA Astrophysics Data System (ADS)

Fathil, M. F. M.; Arshad, M. K. Md; Gopinath, Subash C. B.; Adzhri, R.; Ruslinda, A. R.; Hashim, U.

2017-03-01

This paper presents preparation and characterization of conventional enzyme-linked immunosorbent assay (ELISA) for cardiac troponin detection to determine the selectivity of the cardiac troponin monoclonal antibodies. Monoclonal antibodies, used to capture and bind the targets in this experiment, are cTnI monoclonal antibody (MAb-cTnI) and cTnT monoclonal antibody (MAb-cTnT), while both cardiac troponin I (cTnI) and T (cTnT) are used as targets. ELISA is performed inside two microtiter plates for MAb-cTnI and MAb-cTnT. For each plate, monoclonal antibodies are tested by various concentrations of cTnI and cTnT ranging from 0-6400 µg/l. The binding selectivity and level of detection between monoclonal antibodies and antigen are determined through visual observation based on the color change inside each well on the plate. ELISA reader is further used to quantitatively measured the optical density of the color changes, thus produced more accurate reading. The results from this experiment are utilized to justify the use of these monoclonal antibodies as bio-receptors for cardiac troponin detection by using field-effect transistor (FET)-based biosensors coupled with substrate-gate in the future.

Cardiac troponin I in sickle cell crisis.

PubMed

Aslam, Ahmad K; Rodriguez, Carlos; Aslam, Ahmed F; Vasavada, Balendu C; Khan, Ijaz A

2009-03-20

Gross and microscopic findings consistent with acute and healed myocardial injury without coronary artery disease have been described in autopsy studies of patients with sickle cell crisis. The present study was designed to determine whether serum levels of cardiac troponin I are elevated in sickle cell crisis. Cardiac troponin I levels were measured in 32 patients age>18 years with the admission diagnosis of sickle cell crisis. All patients had cardiac troponin I level drawn >24 h after the onset of symptoms. The clinical profile and electrocardiograms were analyzed. Out of 32 patients, 2 patients had serum cardiac troponin I elevated, both had presented with acute chest syndrome. Serum cardiac troponin I may be elevated during sickle cell crisis, possibly by myocardial ischemia resulting from microvascular coronary obstruction during sickle cell crisis.

The Influence of Cardiac Risk Factor Burden on Cardiac Stress Test Outcomes.

PubMed

Schrock, Jon W; Li, Morgan; Orazulike, Chidubem; Emerman, Charles L

2011-06-01

Chest pain is the most common admission diagnosis for observation unit patients. These patients often undergo cardiac stress testing to further risk stratify for coronary artery disease (CAD). The decision of whom to stress is currently based on clinical judgment. We sought to determine the influence of cardiac risk factor burden on cardiac stress test outcome for patients tested from an observation unit, inpatient or outpatient setting. We performed a retrospective observational cohort study for all patients undergoing stress testing in our institution from June 2006 through July 2007. Cardiac risk factors were collected at the time of stress testing. Risk factors were evaluated in a summative fashion using multivariate regression adjusting for age and known coronary artery disease. The model was tested for goodness of fit and collinearity and the c statistic was calculated using the receiver operating curve. A total of 4026 subjects were included for analysis of which 22% had known CAD. The rates of positive outcome were 89 (12.0%), 95 (12.6%), and 343 (16.9%) for the OU, outpatients, and hospitalized patients respectively. While the odds of a positive test outcome increased for additional cardiac risk factors, ROC curve analysis indicates that simply adding the number of risk factors does not add significant diagnostic value. Hospitalized patients were more likely to have a positive stress test, OR 1.41 (1.10 - 1.81). Our study does not support basing the decision to perform a stress test on the number of cardiac risk factors.

Sarcomere length dependence of rat skinned cardiac myocyte mechanical properties: dependence on myosin heavy chain

PubMed Central

Korte, F Steven; McDonald, Kerry S

2007-01-01

The effects of sarcomere length (SL) on sarcomeric loaded shortening velocity, power output and rates of force development were examined in rat skinned cardiac myocytes that contained either α-myosin heavy chain (α-MyHC) or β-MyHC at 12 ± 1°C. When SL was decreased from 2.3 μm to 2.0 μm submaximal isometric force decreased ∼40% in both α-MyHC and β-MyHC myocytes while peak absolute power output decreased 55% in α-MyHC myocytes and 70% in β-MyHC myocytes. After normalization for the fall in force, peak power output decreased about twice as much in β-MyHC as in α-MyHC myocytes (41%versus 20%). To determine whether the fall in normalized power was due to the lower force levels, [Ca2+] was increased at short SL to match force at long SL. Surprisingly, this led to a 32% greater peak normalized power output at short SL compared to long SL in α-MyHC myocytes, whereas in β-MyHC myocytes peak normalized power output remained depressed at short SL. The role that interfilament spacing plays in determining SL dependence of power was tested by myocyte compression at short SL. Addition of 2% dextran at short SL decreased myocyte width and increased force to levels obtained at long SL, and increased peak normalized power output to values greater than at long SL in both α-MyHC and β-MyHC myocytes. The rate constant of force development (ktr) was also measured and was not different between long and short SL at the same [Ca2+] in α-MyHC myocytes but was greater at short SL in β-MyHC myocytes. At short SL with matched force by either dextran or [Ca2+], ktr was greater than at long SL in both α-MyHC and β-MyHC myocytes. Overall, these results are consistent with the idea that an intrinsic length component increases loaded crossbridge cycling rates at short SL and β-MyHC myocytes exhibit a greater sarcomere length dependence of power output. PMID:17347271

Effects of nifedipine and captopril on vascular capacitance of ganglion-blocked anesthetized dogs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1990-03-01

The hemodynamic effects of nifedipine and captopril at doses producing similar reductions in arterial pressure were studied in pentobarbital-anesthetized ventilated dogs after splenectomy during ganglion blockade with hexamethonium. Mean circulatory filling pressure (Pmcf) was determined during transient circulatory arrest induced by acetylcholine at baseline circulating blood volumes and after increases of 5 and 10 mL/kg. Central blood volumes (pulmonary artery to aortic root) were determined from transit times, and separately determined cardiac outputs (right atrium to pulmonary artery) were estimated by thermodilution. Nifedipine (n = 5) increased Pmcf at all circulating blood volumes and reduced total vascular capacitance without a change in total vascular compliance. Central blood volume, right atrial pressure, and cardiac output were increased with induced increases in circulating blood volume. In contrast, captopril (n = 5) did not alter total vascular capacitance, central blood volume, right atrial pressure, or cardiac output at baseline or with increased circulating volume. Thus, at doses producing similar reductions in arterial pressure, nifedipine but not captopril increased venous return and cardiac output in ganglion-blocked dogs.

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

PubMed Central

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

2013-01-01

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 μg 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 μm), 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 (Δcardiac output: 2.9 ± 2.0 vs. 10.6 ± 1.2 ml min−1) or afterload (Δcardiac 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

Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation - Acute phase results from a prospective observational study.

PubMed

Marques, Pedro; Nobre Menezes, Miguel; Lima da Silva, Gustavo; Bernardes, Ana; Magalhães, Andreia; Cortez-Dias, Nuno; Carpinteiro, Luís; de Sousa, João; Pinto, Fausto J

2016-06-01

Multi-site pacing is emerging as a new method for improving response to cardiac resynchronization therapy (CRT), but has been little studied, especially in patients with atrial fibrillation. We aimed to assess the effects of triple-site (Tri-V) vs. biventricular (Bi-V) pacing on hemodynamics and QRS duration. This was a prospective observational study of patients with permanent atrial fibrillation and ejection fraction <40% undergoing CRT implantation (n=40). One right ventricular (RV) lead was implanted in the apex and another in the right ventricular outflow tract (RVOT) septal wall. A left ventricular (LV) lead was implanted in a conventional venous epicardial position. Cardiac output (using the FloTrac™ Vigileo™ system), mean QRS and ejection fraction were calculated. Mean cardiac output was 4.81±0.97 l/min with Tri-V, 4.68±0.94 l/min with RVOT septal and LV pacing, and 4.68±0.94 l/min with RV apical and LV pacing (p<0.001 for Tri-V vs. both BiV). Mean pre-implantation QRS was 170±25 ms, 123±18 ms with Tri-V, 141±25 ms with RVOT septal pacing and LV pacing and 145±19 with RV apical and LV pacing (p<0.001 for Tri-V vs. both BiV and pre-implantation). Mean ejection fraction was significantly higher with Tri-V (30±11%) vs. Bi-V pacing (28±12% with RVOT septal and LV pacing and 28±11 with RV apical and LV pacing) and pre-implantation (25±8%). Tri-V pacing produced higher cardiac output and shorter QRS duration than Bi-V pacing. This may have a significant impact on the future of CRT. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Hawthorn Herb Increases the Risk of Bleeding after Cardiac Surgery: An Evidence-Based Approach.

PubMed

Rababa'h, Abeer M; Altarabsheh, Salah E; Haddad, Osama; Deo, Salil V; Obeidat, Yagthan; Al-Azzam, Sayer

2016-08-22

Hawthorn extract consumption is becoming more widespread among the Jordanian population with cardiovascular disorders. We conducted this prospective observational longitudinal study to determine the impact of hawthorn extract on bleeding risk in patients who undergo cardiac surgery. A prospective observational study was performed on 116 patients who underwent cardiac surgery in the period between June 2014 and May 2015. Patients were divided into two groups: Group I (patients recently consumed hawthorn extract) and Group II (patients never consumed hawthorn extract). Endpoint measures included the rates of reopening to control bleeding, early mortality, duration of intensive care unit stay, total in-hospital stay period, and duration and amount of chest tube drainage. Hawthorn patients had a significantly higher rate of postoperative bleeding necessitating take back to the operating room compared to the control group (10% versus 1%; P = .03) respectively. The overall mortality rate for group I and II was 4% and 0% respectively; P = .17. Chest tubes were kept in for longer times in group I compared to group II (54 ± 14.6 versus 49 ± 14.7 hours respectively; P = .01). Group I stayed longer in the intensive care unit compared to group II (24 versus 22 hours respectively; P = .01). The total in-hospital stay period was comparable between the two groups. Hawthorn extract consumption does increase the potential for bleeding and the amount of chest tube output after cardiac surgery.

Endonuclease G is a novel determinant of cardiac hypertrophy and mitochondrial function

PubMed Central

McDermott-Roe, Chris; Ye, Junmei; Ahmed, Rizwan; Sun, Xi-Ming; Serafín, Anna; Ware, James; Bottolo, Leonardo; Muckett, Phil; Cañas, Xavier; Zhang, Jisheng; Rowe, Glenn C.; Buchan, Rachel; Lu, Han; Braithwaite, Adam; Mancini, Massimiliano; Hauton, David; Martí, Ramon; García-Arumí, Elena; Hubner, Norbert; Jacob, Howard; Serikawa, Tadao; Zidek, Vaclav; Papousek, Frantisek; Kolar, Frantisek; Cardona, Maria; Ruiz-Meana, Marisol; García-Dorado, David; Comella, Joan X; Felkin, Leanne E; Barton, Paul JR; Arany, Zoltan; Pravenec, Michal; Petretto, Enrico; Sanchis, Daniel; Cook, Stuart A.

2011-01-01

Left ventricular mass (LVM) is a highly heritable trait1 and an independent risk factor for all-cause mortality2. To date, genome-wide association studies (GWASs) have not identified the genetic factors underlying LVM variation3 and the regulatory mechanisms for blood pressure (BP)-independent cardiac hypertrophy remain poorly understood4,5. Unbiased systems-genetics approaches in the rat6,7 now provide a powerful complementary tool to GWAS and we applied integrative genomics to dissect a highly replicated, BP-independent LVM locus on rat chromosome 3p. We identified endonuclease G (Endog), previously implicated in apoptosis8 but not hypertrophy, as the gene at the locus and demonstrated loss-of-function mutation in Endog associated with increased LVM and impaired cardiac function. Inhibition of Endog in cultured cardiomyocytes resulted in an increase in cell size and hypertrophic biomarkers in the absence of pro-hypertrophic stimulation. Genome-wide network analysis unexpectedly inferred ENDOG in fundamental mitochondrial processes unrelated to apoptosis. We showed direct regulation of ENDOG by ERRα and PGC1α, master regulators of mitochondrial and cardiac function9,10,11, interaction of ENDOG with the mitochondrial genome and ENDOG-mediated regulation of mitochondrial mass. At baseline, Endog deleted mouse heart had depleted mitochondria, mitochondrial dysfunction and elevated reactive oxygen species (ROS), which was associated with enlarged and steatotic cardiomyocytes. Our studies establish further the link between mitochondrial dysfunction, ROS and heart disease and demonstrate a new role for Endog in maladaptive cardiac hypertrophy. PMID:21979051

Augmented Renal Clearance in Traumatic Brain Injury: A Single-Center Observational Study of Atrial Natriuretic Peptide, Cardiac Output, and Creatinine Clearance.

PubMed

Udy, Andrew A; Jarrett, Paul; Lassig-Smith, Melissa; Stuart, Janine; Starr, Therese; Dunlop, Rachel; Deans, Renae; Roberts, Jason A; Senthuran, Siva; Boots, Robert; Bisht, Kavita; Bulmer, Andrew C; Lipman, Jeffrey

2017-01-01

Augmented renal clearance (ARC) is being increasingly described in neurocritical care practice. The mechanisms driving this phenomenon are largely unknown. The aim of this project was therefore to explore changes in renal function, cardiac output (CO), and atrial natriuretic peptide (ANP) concentrations in patients with isolated traumatic brain injury (TBI). This prospective observational cohort study was conducted in a tertiary-level, university-affiliated intensive care unit (ICU). Patients with normal plasma creatinine concentrations (<120 μmol/L) at admission and no history of chronic kidney disease, admitted with isolated TBI, were eligible for enrollment. Continuous CO measures were obtained using arterial pulse waveform analysis. Eight-hour urinary creatinine clearances (CL CR ) were used to quantify renal function. ANP concentrations in plasma were measured on alternate days. Data were collected from study enrollment until ICU discharge, death, or day 15, which ever came first. Eleven patients, contributing 100 ICU days of physiological data, were enrolled into the study. Most participants were young men, requiring mechanical ventilation. Median ICU length of stay was 9.6 [7.8-13.0] days. Elevated CL CR measures (>150 mL/min) were frequent and appeared to parallel changes in CO. Plasma ANP concentrations were also significantly elevated over the study period (minimum value = 243 pg/mL). These data suggest that ARC is likely to complicate the care of TBI patients with normal plasma creatinine concentrations, and may be driven by associated cardiovascular changes and/or elevated plasma ANP concentrations. However, significant additional research is required to further understand these findings.

Chronic reduction in cardiac output induces hypoxic signaling in larval zebrafish even at a time when convective oxygen transport is not required.

PubMed

Kopp, Renate; Schwerte, Thorsten; Egg, Margit; Sandbichler, Adolf Michael; Egger, Bernhard; Pelster, Bernd

2010-09-01

In the present study, the zebrafish breakdance mutant (bre) was used to assess the role of blood flow in development because it has been previously shown that bre larvae have a chronically reduced cardiac output as a result of ventricular contraction following only every second atrial contraction in addition to an atrial bradycardia. We confirmed a 50% reduction compared with control fish and further showed that blood flow in the caudal part of the dorsal aorta decreased by 80%. Associated with these reductions in blood flow were indications of developmental retardation in bre mutants, specifically delayed hatching, reduced cell proliferation, and a transiently decreased growth rate. Surprisingly, an increased red blood cell concentration and an earlier appearance of trunk vessels in bre larvae indicated some compensation to convective oxygen transport, although in previous studies it has been shown that zebrafish larvae at this stage obtain oxygen by bulk diffusion. In bre animals immunohistochemical analyses showed a significant increase in hypoxia inducible factor 1 (HIF)-α protein expression, comparable with wild-type larvae that were raised under hypoxic conditions. Accordingly, the expression of some hif downstream genes was affected. Furthermore, Affymetrix microarray analyses revealed a large number of genes that were differently expressed comparing control and bre larvae, and the number even increased with proceeding development. The results showed that a chronic reduction in blood flow generated hypoxic molecular signals despite partial compensation by increased oxygen carrying capacity and transiently slowed the overall development of zebrafish bre larvae.

Patterns and determinants of functional and absolute iron deficiency in patients undergoing cardiac rehabilitation following heart surgery.

PubMed

Tramarin, Roberto; Pistuddi, Valeria; Maresca, Luigi; Pavesi, Marco; Castelvecchio, Serenella; Menicanti, Lorenzo; de Vincentiis, Carlo; Ranucci, Marco

2017-05-01

Background Anaemia and iron deficiency are frequent following major surgery. The present study aims to identify the iron deficiency patterns in cardiac surgery patients at their admission to a cardiac rehabilitation programme, and to determine which perioperative risk factor(s) may be associated with functional and absolute iron deficiency. Design This was a retrospective study on prospectively collected data. Methods The patient population included 339 patients. Functional iron deficiency was defined in the presence of transferrin saturation <20% and serum ferritin ≥100 µg/l. Absolute iron deficiency was defined in the presence of serum ferritin values <100 µg/l. Results Functional iron deficiency was found in 62.9% of patients and absolute iron deficiency in 10% of the patients. At a multivariable analysis, absolute iron deficiency was significantly ( p = 0.001) associated with mechanical prosthesis mitral valve replacement (odds ratio 5.4, 95% confidence interval 1.9-15) and tissue valve aortic valve replacement (odds ratio 4.5, 95% confidence interval 1.9-11). In mitral valve surgery, mitral repair carried a significant ( p = 0.013) lower risk of absolute iron deficiency (4.4%) than mitral valve replacement with tissue valves (8.3%) or mechanical prostheses (22.5%). Postoperative outcome did not differ between patients with functional iron deficiency and patients without iron deficiency; patients with absolute iron deficiency had a significantly ( p = 0.017) longer postoperative hospital stay (median 11 days) than patients without iron deficiency (median nine days) or with functional iron deficiency (median eight days). Conclusions Absolute iron deficiency following cardiac surgery is more frequent in heart valve surgery and is associated with a prolonged hospital stay. Routine screening for iron deficiency at admission in the cardiac rehabilitation unit is suggested.

Estradiol improves cardiac and hepatic function after trauma-hemorrhage: role of enhanced heat shock protein expression.

PubMed

Szalay, László; Shimizu, Tomoharu; Suzuki, Takao; Yu, Huang-Ping; Choudhry, Mashkoor A; Schwacha, Martin G; Rue, Loring W; Bland, Kirby I; Chaudry, Irshad H

2006-03-01

Although studies indicate that 17beta-estradiol administration after trauma-hemorrhage (T-H) improves cardiac and hepatic functions, the underlying mechanisms remain unclear. Because the induction of heat shock proteins (HSPs) can protect cardiac and hepatic functions, we hypothesized that these proteins contribute to the salutary effects of estradiol after T-H. To test this hypothesis, male Sprague-Dawley rats ( approximately 300 g) underwent laparotomy and hemorrhagic shock (35-40 mmHg for approximately 90 min) followed by resuscitation with four times the shed blood volume in the form of Ringer lactate. 17beta-estradiol (1 mg/kg body wt) was administered at the end of the resuscitation. Five hours after T-H and resuscitation there was a significant decrease in cardiac output, positive and negative maximal rate of left ventricular pressure. Liver function as determined by bile production and indocyanine green clearance was also compromised after T-H and resuscitation. This was accompanied by an increase in plasma alanine aminotransferase (ALT) levels and liver perfusate lactic dehydrogenase levels. Furthermore, circulating levels of TNF-alpha, IL-6, and IL-10 were also increased. In addition to decreased cardiac and hepatic function, there was an increase in cardiac HSP32 expression and a reduction in HSP60 expression after T-H. In the liver, HSP32 and HSP70 were increased after T-H. There was no change in heart HSP70 and liver HSP60 after T-H and resuscitation. Estradiol administration at the end of T-H and resuscitation increased heart/liver HSPs expression, ameliorated the impairment of heart/liver functions, and significantly prevented the increase in plasma levels of ALT, TNF-alpha, and IL-6. The ability of estradiol to induce HSPs expression in the heart and the liver suggests that HSPs, in part, mediate the salutary effects of 17beta-estradiol on organ functions after T-H.

Random forests ensemble classifier trained with data resampling strategy to improve cardiac arrhythmia diagnosis.

PubMed

Ozçift, Akin

2011-05-01

Supervised classification algorithms are commonly used in the designing of computer-aided diagnosis systems. In this study, we present a resampling strategy based Random Forests (RF) ensemble classifier to improve diagnosis of cardiac arrhythmia. Random forests is an ensemble classifier that consists of many decision trees and outputs the class that is the mode of the class's output by individual trees. In this way, an RF ensemble classifier performs better than a single tree from classification performance point of view. In general, multiclass datasets having unbalanced distribution of sample sizes are difficult to analyze in terms of class discrimination. Cardiac arrhythmia is such a dataset that has multiple classes with small sample sizes and it is therefore adequate to test our resampling based training strategy. The dataset contains 452 samples in fourteen types of arrhythmias and eleven of these classes have sample sizes less than 15. Our diagnosis strategy consists of two parts: (i) a correlation based feature selection algorithm is used to select relevant features from cardiac arrhythmia dataset. (ii) RF machine learning algorithm is used to evaluate the performance of selected features with and without simple random sampling to evaluate the efficiency of proposed training strategy. The resultant accuracy of the classifier is found to be 90.0% and this is a quite high diagnosis performance for cardiac arrhythmia. Furthermore, three case studies, i.e., thyroid, cardiotocography and audiology, are used to benchmark the effectiveness of the proposed method. The results of experiments demonstrated the efficiency of random sampling strategy in training RF ensemble classification algorithm. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Chronic surplus of Japanese cardiac surgeon--ideal nurse practitioner for cardiac surgery, cardiac surgeon's attitude toward the future].

PubMed

Ikegami, Hirohisa

2014-03-01

It is chronically surplus of doctors in the world of cardiac surgery. There are too many cardiac surgeons because cardiac surgery requires a large amount of manpower resources to provide adequate medical services. Many Japanese cardiac surgeons do not have enough opportunity to perform cardiac surgery operations, and many Japanese cardiac surgery residents do not have enough opportunity to learn cardiac surgery operations. There are physician assistants and nurse practitioners in the US. Because they provide a part of medical care to cardiac surgery patients, American cardiac surgeons can focus more energy on operative procedures. Introduction of cardiac surgery specialized nurse practitioner is essential to deliver a high quality medical service as well as to solve chronic problems that Japanese cardiac surgery has had for a long time.

Pregestational type 2 diabetes mellitus induces cardiac hypertrophy in the murine embryo through cardiac remodeling and fibrosis.

PubMed

Lin, Xue; Yang, Penghua; Reece, E Albert; Yang, Peixin

2017-08-01

Cardiac hypertrophy is highly prevalent in patients with type 2 diabetes mellitus. Experimental evidence has implied that pregnant women with type 2 diabetes mellitus and their children are at an increased risk of cardiovascular diseases. Our previous mouse model study revealed that maternal type 2 diabetes mellitus induces structural heart defects in their offspring. This study aims to determine whether maternal type 2 diabetes mellitus induces embryonic heart hypertrophy in a murine model of diabetic embryopathy. The type 2 diabetes mellitus embryopathy model was established by feeding 4-week-old female C57BL/6J mice with a high-fat diet for 15 weeks. Cardiac hypertrophy in embryos at embryonic day 17.5 was characterized by measuring heart size and thickness of the right and left ventricle walls and the interventricular septum, as well as the expression of β-myosin heavy chain, atrial natriuretic peptide, insulin-like growth factor-1, desmin, and adrenomedullin. Cardiac remodeling was determined by collagen synthesis and fibronectin synthesis. Fibrosis was evaluated by Masson staining and determining the expression of connective tissue growth factor, osteopontin, and galectin-3 genes. Cell apoptosis also was measured in the developing heart. The thicknesses of the left ventricle walls and the interventricular septum of embryonic hearts exposed to maternal diabetes were significantly thicker than those in the nondiabetic group. Maternal diabetes significantly increased β-myosin heavy chain, atrial natriuretic peptide, insulin-like growth factor-1, and desmin expression, but decreased expression of adrenomedullin. Moreover, collagen synthesis was significantly elevated, whereas fibronectin synthesis was suppressed, in embryonic hearts from diabetic dams, suggesting that cardiac remodeling is a contributing factor to cardiac hypertrophy. The cardiac fibrosis marker, galectin-3, was induced by maternal diabetes. Furthermore, maternal type 2 diabetes mellitus

Determinants of Acute Kidney Injury Duration After Cardiac Surgery: An Externally Validated Tool

PubMed Central

Brown, Jeremiah R.; Kramer, Robert S.; MacKenzie, Todd A.; Coca, Steven G.; Sint, Kyaw; Parikh, Chirag R.

2013-01-01

Background Acute kidney injury (AKI) duration following cardiac surgery is associated with poor survival in a dose-dependent manner. However, it is not known what peri-operative risk factors contribute to prolonged AKI and delayed recovery. We sought to identify peri-operative risk factors that predict duration of AKI, a complication that effects short and long term survival. Methods We studied 4,987 consecutive cardiac surgery patients from 2002 through 2007. AKI was defined as a ≥0.3 (mg/dL) or ≥50% increase in SCr from baseline. Duration of AKI was defined by the number of days AKI was present. Step-wise multivariable negative binomial regression analysis was conducted using peri-operative risk factors for AKI duration. C-index was estimated by Kendall’s tau. Results AKI developed in 39% of patients with a median duration of AKI at 3 days and ranged from 1 to 108 days. Patients without AKI had duration of zero days. Independent predictors of AKI duration included baseline patient and disease characteristics, operative and post-operative factors. Prediction for mean duration of AKI was developed using coefficients from the regression model and externally validated the model on 1,219 cardiac surgery patients in a separate cardiac surgery cohort (TRIBE-AKI). The C-index was 0.65 (p<0.001) for the derivation cohort and 0.62 (p<0.001) for the validation cohort. Conclusion We identified and externally validated peri-operative predictors of AKI duration. These risk-factors will be useful to evaluate a patient’s risk for the tempo of recovery from AKI after cardiac surgery and subsequent short and long term survival. The level of awareness created by working with these risk factors have implications regarding positive changes in processes of care that have the potential to decrease the incidence and mitigate AKI. PMID:22206952

Neurologic Complications After Cardiac Transplant.

PubMed

Öcal, Ruhsen; Kibaroğlu, Seda; Derle, Eda; Tanoğlu, Ceyda; Camkıran, Aynur; Pirat, Arash; Can, Ufuk; Sezgin, Atilla

2016-06-15

Cardiac transplant is the best available therapy for patients with end-stage heart failure. Neurologic complications occur at a rate of 30% to 70% in patients undergoing cardiac transplant, and they affect mortality and morbidity of these patients. Risk factors for neurologic complications include immunosuppressive medication toxicity, infections, brain lesions, and metabolic disorders. The aim of our study was to determine the incidence of neurologic complications in adult patients undergoing cardiac transplant. We retrospectively evaluated the medical records of 70 patients who underwent cardiac transplant between 2004 and April 2016. We recorded the demographic data, neurologic symptoms, neurologic examination findings, laboratory test results, brain imaging study results, and treatments received of the patients. Of the 70 patients enrolled, 55 were male and 15 were female patients. The age range was 18 to 63 years, and the mean age was 42.4 years. Twelve patients had encephalopathy, 4 had neuropathic pain, 3 had tremor, 2 had ischemic cerebrovascular accident, 7 had posterior reversible encephalopathy syndrome, and 1 had drop foot. Encephalopathy usually developed secondary to other neurologic disorders. The incidence of neurologic complications in adult patients undergoing cardiac transplant was 30%. Neurologic complications are common after cardiac transplant. We observed an incidence of 30% for neurologic complications in our clinic, with encephalopathy being the most common complication. Encephalopathy most commonly developed secondary to posterior reversible encephalopathy syndrome.

Geraniol alleviates diabetic cardiac complications: Effect on cardiac ischemia and oxidative stress.

PubMed

El-Bassossy, Hany M; Ghaleb, Hanna; Elberry, Ahmed A; Balamash, Khadijah S; Ghareib, Salah A; Azhar, Ahmad; Banjar, Zainy

2017-04-01

The present study was planned to assess the possible protective effect of geraniol on cardiovascular complications in an animal model with diabetes. Diabetes was induced in rats by a single streptozotocin injection. In the treated group, geraniol (150mgkg -1 day -1 ) was administered orally starting from the 15th day after induction of diabetes, and ending after 7 weeks; diabetic control rats were given vehicle for the same period. At the end of the study, cardiac contractility was assessed by using a Millar microtip catheter in anesthetised rats, and cardiac conductivity determined by a surface ECG. Serum levels of glucose, cholesterol, triglyceride and adiponectin as well as urine 8-isoprostane were determined. In addition, cardiac superoxide dismutase (SOD) and catalase activity were measured. Geraniol administration significantly alleviated the attenuated cardiac systolic function associated with diabetes as indicated by inhibiting the decrease in the rate of rise (dP/dt max ) in ventricular pressure and the increase in systolic duration observed in diabetic rats. In addition, geraniol alleviated impaired diastolic function as shown by inhibiting the decrease in the rate of fall (dP/dt min ) in ventricular pressure and increased isovolumic relaxation constant (Tau) observed in diabetic rats. ECG recordings showed that geraniol prevented any increase in QTc and T-peak-T-end intervals, and markers of LV ischemia and arrhythmogenesis, seen in diabetic animals. Geraniol suppressed the exaggerated oxidative stress as evidenced by preventing the increase in 8-isoprotane. In diabetic heart tissue, geraniol prevented the inhibition in catalase activity but did not affect the heart SOD. Geraniol partially reduced hyperglycemia, prevented the hypercholesterolemia, but did not affect the serum level of adiponectin in diabetic animals. Results obtained in this study suggest that geraniol provides a potent protective effect against cardiac dysfunction induced by diabetes

High-Speed Binary-Output Image Sensor

NASA Technical Reports Server (NTRS)

Fossum, Eric; Panicacci, Roger A.; Kemeny, Sabrina E.; Jones, Peter D.

1996-01-01

Photodetector outputs digitized by circuitry on same integrated-circuit chip. Developmental special-purpose binary-output image sensor designed to capture up to 1,000 images per second, with resolution greater than 10 to the 6th power pixels per image. Lower-resolution but higher-frame-rate prototype of sensor contains 128 x 128 array of photodiodes on complementary metal oxide/semiconductor (CMOS) integrated-circuit chip. In application for which it is being developed, sensor used to examine helicopter oil to determine whether amount of metal and sand in oil sufficient to warrant replacement.

Cardiac catheterization - discharge

MedlinePlus

Catheterization - cardiac - discharge; Heart catheterization - discharge: Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization discharge; CAD - cardiac catheterization discharge; Coronary artery disease - cardiac catheterization ...

Cardiac abnormalities in Parkinson's disease and Parkinsonism.

PubMed

Scorza, Fulvio A; Fiorini, Ana C; Scorza, Carla A; Finsterer, Josef

2018-07-01

Though there is increasing evidence for primary cardiac disease in Parkinson's disease (PD) and Parkinsonism (PS), this evidence is hardly included in the general management of these patients. Literature review. PD is one of the most common age-related neurodegenerative disorders. Epidemiological studies have shown that PD is accompanied by high rates of premature death compared with the general population. In general, death in PD/PS is usually caused by determinant factors such as pneumonia, cerebrovascular, and cardiovascular disease. There is a significant body of literature demonstrating involvement of the heart in PD/PS. Cardiac involvement in PD/PS includes cardiac autonomic dysfunction, cardiomyopathy, coronary heart disease, arrhythmias, conduction defects, and sudden cardiac death (SCD), and sudden unexpected death in Parkinson's disease (SUDPAR). Cardiac abnormalities found in PD/PS are manifold but the most prominent is cardiac autonomic dysfunction. The frequency of coronary heart disease in PD is a matter of debate. Only rarely reported in PD/PS are cardiomyopathies, arrhythmias, and sudden cardiac death, and SUDPAR. It is particularly recommended that PD/PS patients are more intensively investigated cardiologically as soon as the diagnosis is established. Early recognition of cardiac involvement is important for preventing SCD and SUDPAR. Copyright © 2018 Elsevier Ltd. All rights reserved.

Glutaredoxin-2 is required to control oxidative phosphorylation in cardiac muscle by mediating deglutathionylation reactions.

PubMed

Mailloux, Ryan J; Xuan, Jian Ying; McBride, Skye; Maharsy, Wael; Thorn, Stephanie; Holterman, Chet E; Kennedy, Christopher R J; Rippstein, Peter; deKemp, Robert; da Silva, Jean; Nemer, Mona; Lou, Marjorie; Harper, Mary-Ellen

2014-05-23

Glutaredoxin-2 (Grx2) modulates the activity of several mitochondrial proteins in cardiac tissue by catalyzing deglutathionylation reactions. However, it remains uncertain whether Grx2 is required to control mitochondrial ATP output in heart. Here, we report that Grx2 plays a vital role modulating mitochondrial energetics and heart physiology by mediating the deglutathionylation of mitochondrial proteins. Deletion of Grx2 (Grx2(-/-)) decreased ATP production by complex I-linked substrates to half that in wild type (WT) mitochondria. Decreased respiration was associated with increased complex I glutathionylation diminishing its activity. Tissue glucose uptake was concomitantly increased. Mitochondrial ATP output and complex I activity could be recovered by restoring the redox environment to that favoring the deglutathionylated states of proteins. Grx2(-/-) hearts also developed left ventricular hypertrophy and fibrosis, and mice became hypertensive. Mitochondrial energetics from Grx2 heterozygotes (Grx2(+/-)) were also dysfunctional, and hearts were hypertrophic. Intriguingly, Grx2(+/-) mice were far less hypertensive than Grx2(-/-) mice. Thus, Grx2 plays a vital role in modulating mitochondrial metabolism in cardiac muscle, and Grx2 deficiency leads to pathology. As mitochondrial ATP production was restored by the addition of reductants, these findings may be relevant to novel redox-related therapies in cardiac disease. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Cardiac Trauma.

PubMed

Gosavi, Sucheta; Tyroch, Alan H; Mukherjee, Debabrata

2016-11-01

Cardiac trauma is a leading cause of death in the United States and occurs mostly due to motor vehicle accidents. Blunt cardiac trauma and penetrating chest injuries are most common, and both can lead to aortic injuries. Timely diagnosis and early management are the key to improve mortality. Cardiac computed tomography and cardiac ultrasound are the 2 most important diagnostic modalities. Mortality related to cardiac trauma remains high despite improvement in diagnosis and management.

Cardiac-CT and Cardiac-MR examinations cost analysis, based on data of four Italian Centers.

PubMed

Centonze, Maurizio; Lorenzin, Giuseppe; Francesconi, Andrea; Cademartiri, Filippo; Casagranda, Giulia; Fusaro, Michele; Ligabue, Guido; Zanetti, Giovanna; Spanti, Demetrio; De Cobelli, Francesco

2016-01-01

To establish the appropriate number of Cardiac-CT and Cardio-MR examinations, to determine an economically justified and sustainable investment in these two technologies, for an exclusive cardiologic use. From July 2013 to July 2014, through a survey in four different Italian Departments of Radiology, data on the costs of Cardiac-CT and Cardiac-MR examinations were collected. For the evaluation of the costs of examinations, it was used an analytical accounting system, considering only the direct costs (consumables, health personnel work time, equipment amortization/maintenance) and other costs (utilities, services, etc.). Indirect costs (general costs) were not assessed. It was made a simulation, assuming an exclusive use of the CT and MR equipments for Cardiac-CT and Cardiac-MR examinations, calculating the annual number necessary to arrive at the Break Even Point (BEP: the point at which cost or expenses and revenue are equal). On the basis of the CT costs, in order to reach the BEP, performing only Cardiac-CT examinations, an average of 2641-2752 examinations/year is needed. The annual time commitment of the Medical Professional to ensure the number of examinations to reach the BEP is 2625-2750 h/year, equivalent to two Medical Doctors in a Cardiology Department. The recent Cardiac-CT Italian Registry, in the period January-June 2011, reports a number of examinations of 3455 patients in 47 different Centers, distributed throughout the whole national territory. With regard to MR, in order to reach the BEP, performing only Cardiac-MR examinations, an average of 2435-3123 examinations/year is needed. The annual time commitment of the Medical Professional to ensure the number of examinations to reach the BEP is 2437-3125 h/year, equivalent to two Medical Doctors in a Cardiology Department. The recent Cardiac-MR Italian Registry reports a number of examinations of 3776 patients in 40 Centers, distributed throughout the whole national territory. This research has

Approach to determine measurement uncertainty in complex nanosystems with multiparametric dependencies and multivariate output quantities

NASA Astrophysics Data System (ADS)

Hampel, B.; Liu, B.; Nording, F.; Ostermann, J.; Struszewski, P.; Langfahl-Klabes, J.; Bieler, M.; Bosse, H.; Güttler, B.; Lemmens, P.; Schilling, M.; Tutsch, R.

2018-03-01

In many cases, the determination of the measurement uncertainty of complex nanosystems provides unexpected challenges. This is in particular true for complex systems with many degrees of freedom, i.e. nanosystems with multiparametric dependencies and multivariate output quantities. The aim of this paper is to address specific questions arising during the uncertainty calculation of such systems. This includes the division of the measurement system into subsystems and the distinction between systematic and statistical influences. We demonstrate that, even if the physical systems under investigation are very different, the corresponding uncertainty calculation can always be realized in a similar manner. This is exemplarily shown in detail for two experiments, namely magnetic nanosensors and ultrafast electro-optical sampling of complex time-domain signals. For these examples the approach for uncertainty calculation following the guide to the expression of uncertainty in measurement (GUM) is explained, in which correlations between multivariate output quantities are captured. To illustate the versatility of the proposed approach, its application to other experiments, namely nanometrological instruments for terahertz microscopy, dimensional scanning probe microscopy, and measurement of concentration of molecules using surface enhanced Raman scattering, is shortly discussed in the appendix. We believe that the proposed approach provides a simple but comprehensive orientation for uncertainty calculation in the discussed measurement scenarios and can also be applied to similar or related situations.

Milrinone ameliorates cardiac mechanical dysfunction after hypothermia in an intact rat model.

PubMed

Dietrichs, Erik Sveberg; Kondratiev, Timofei; Tveita, Torkjel

2014-12-01

Rewarming from hypothermia is often complicated by cardiac dysfunction, characterized by substantial reduction in stroke volume. Previously we have reported that inotropic agents, working via cardiac β-receptor agonism may exert serious side effects when applied to treat cardiac contractile dysfunction during rewarming. In this study we tested whether Milrinone, a phosphodiesterase III inhibitor, is able to ameliorate such dysfunction when given during rewarming. A rat model designed for circulatory studies during experimental hypothermia with cooling to a core temperature of 15°C, stable hypothermia at this temperature for 3h and subsequent rewarming was used, with a total of 3 groups: (1) a normothermic group receiving Milrinone, (2) a hypothermic group receiving Milrinone the last hour of hypothermia and during rewarming, and (3) a hypothermic saline control group. Hemodynamic function was monitored using a conductance catheter introduced to the left ventricle. After rewarming from 15°C, stroke volume and cardiac output returned to within baseline values in Milrinone treated animals, while these variables were significantly reduced in saline controls. Milrinone ameliorated cardiac dysfunction during rewarming from 15°C. The present results suggest that at low core temperatures and during rewarming from such temperatures, pharmacologic efforts to support cardiovascular function is better achieved by substances preventing cyclic AMP breakdown rather than increasing its formation via β-receptor stimulation. Copyright © 2014 Elsevier Inc. All rights reserved.

In Vivo Self-Powered Wireless Cardiac Monitoring via Implantable Triboelectric Nanogenerator.

PubMed

Zheng, Qiang; Zhang, Hao; Shi, Bojing; Xue, Xiang; Liu, Zhuo; Jin, Yiming; Ma, Ye; Zou, Yang; Wang, Xinxin; An, Zhao; Tang, Wei; Zhang, Wei; Yang, Fan; Liu, Yang; Lang, Xilong; Xu, Zhiyun; Li, Zhou; Wang, Zhong Lin

2016-07-26

Harvesting biomechanical energy in vivo is an important route in obtaining sustainable electric energy for powering implantable medical devices. Here, we demonstrate an innovative implantable triboelectric nanogenerator (iTENG) for in vivo biomechanical energy harvesting. Driven by the heartbeat of adult swine, the output voltage and the corresponding current were improved by factors of 3.5 and 25, respectively, compared with the reported in vivo output performance of biomechanical energy conversion devices. In addition, the in vivo evaluation of the iTENG was demonstrated for over 72 h of implantation, during which the iTENG generated electricity continuously in the active animal. Due to its excellent in vivo performance, a self-powered wireless transmission system was fabricated for real-time wireless cardiac monitoring. Given its outstanding in vivo output and stability, iTENG can be applied not only to power implantable medical devices but also possibly to fabricate a self-powered, wireless healthcare monitoring system.

Comparison of cardiac output optimization with an automated closed-loop goal-directed fluid therapy versus non standardized manual fluid administration during elective abdominal surgery: first prospective randomized controlled trial.

PubMed

Lilot, Marc; Bellon, Amandine; Gueugnon, Marine; Laplace, Marie-Christine; Baffeleuf, Bruno; Hacquard, Pauline; Barthomeuf, Felicie; Parent, Camille; Tran, Thomas; Soubirou, Jean-Luc; Robinson, Philip; Bouvet, Lionel; Vassal, Olivia; Lehot, Jean-Jacques; Piriou, Vincent

2018-01-27

An intraoperative automated closed-loop system for goal-directed fluid therapy has been successfully tested in silico, in vivo and in a clinical case-control matching. This trial compared intraoperative cardiac output (CO) in patients managed with this closed-loop system versus usual practice in an academic medical center. The closed-loop system was connected to a CO monitoring system and delivered automated colloid fluid boluses. Moderate to high-risk abdominal surgical patients were randomized either to the closed-loop or the manual group. Intraoperative final CO was the primary endpoint. Secondary endpoints were intraoperative overall mean cardiac index (CI), increase from initial to final CI, intraoperative fluid volume and postoperative outcomes. From January 2014 to November 2015, 46 patients were randomized. There was a lower initial CI (2.06 vs. 2.51 l min -1 m -2 , p = 0.042) in the closed-loop compared to the control group. No difference in final CO and in overall mean intraoperative CI was observed between groups. A significant relative increase from initial to final CI values was observed in the closed-loop but not the control group (+ 28.6%, p = 0.006 vs. + 1.2%, p = 0.843). No difference was found for intraoperative fluid management and postoperative outcomes between groups. There was no significant impact on the primary study endpoint, but this was found in a context of unexpected lower initial CI in the closed-loop group.Trial registry number ID-RCB/EudraCT: 2013-A00770-45. ClinicalTrials.gov Identifier NCT01950845, date of registration: 17 September 2013.

Cooperative activation of cardiac transcription through myocardin bridging of paired MEF2 sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Courtney M.; Hu, Jianxin; Thomas, Reuben

2017-03-28

Enhancers frequently contain multiple binding sites for the same transcription factor. These homotypic binding sites often exhibit synergy, whereby the transcriptional output from two or more binding sites is greater than the sum of the contributions of the individual binding sites alone. Although this phenomenon is frequently observed, the mechanistic basis for homotypic binding site synergy is poorly understood. Here in this paper, we identify a bona fide cardiac-specific Prkaa2 enhancer that is synergistically activated by homotypic MEF2 binding sites. We show that two MEF2 sites in the enhancer function cooperatively due to bridging of the MEF2C-bound sites by themore » SAP domain-containing co-activator protein myocardin, and we show that paired sites buffer the enhancer from integration site-dependent effects on transcription in vivo. Paired MEF2 sites are prevalent in cardiac enhancers, suggesting that this might be a common mechanism underlying synergy in the control of cardiac gene expression in vivo.« less

Embryonic caffeine exposure acts via A1 adenosine receptors to alter adult cardiac function and DNA methylation in mice.

PubMed

Buscariollo, Daniela L; Fang, Xiefan; Greenwood, Victoria; Xue, Huiling; Rivkees, Scott A; Wendler, Christopher C

2014-01-01

Evidence indicates that disruption of normal prenatal development influences an individual's risk of developing obesity and cardiovascular disease as an adult. Thus, understanding how in utero exposure to chemical agents leads to increased susceptibility to adult diseases is a critical health related issue. Our aim was to determine whether adenosine A1 receptors (A1ARs) mediate the long-term effects of in utero caffeine exposure on cardiac function and whether these long-term effects are the result of changes in DNA methylation patterns in adult hearts. Pregnant A1AR knockout mice were treated with caffeine (20 mg/kg) or vehicle (0.09% NaCl) i.p. at embryonic day 8.5. This caffeine treatment results in serum levels equivalent to the consumption of 2-4 cups of coffee in humans. After dams gave birth, offspring were examined at 8-10 weeks of age. A1AR+/+ offspring treated in utero with caffeine were 10% heavier than vehicle controls. Using echocardiography, we observed altered cardiac function and morphology in adult mice exposed to caffeine in utero. Caffeine treatment decreased cardiac output by 11% and increased left ventricular wall thickness by 29% during diastole. Using DNA methylation arrays, we identified altered DNA methylation patterns in A1AR+/+ caffeine treated hearts, including 7719 differentially methylated regions (DMRs) within the genome and an overall decrease in DNA methylation of 26%. Analysis of genes associated with DMRs revealed that many are associated with cardiac hypertrophy. These data demonstrate that A1ARs mediate in utero caffeine effects on cardiac function and growth and that caffeine exposure leads to changes in DNA methylation.

Rodent Studies of Cardiovascular Deconditioning

NASA Technical Reports Server (NTRS)

Shoukas, Artin A.

1999-01-01

Changes in blood pressure can occur for two reasons: 1) A decrease in cardiac output resulting from the altered contractility of the heart or through changes in venous filling pressure via the Frank Starling mechanism or; 2) A change in systemic vascular resistance. The observed changes in cardiac output and blood pressure after long term space flight cannot be entirely explained through changes in contractility or heart rate alone. Therefore, alterations in filling pressure mediated through changes in systemic venous capacitance and arterial resistance function may be important determinants of cardiac output and blood pressure after long term space flight. Our laboratory and previous studies have shown the importance of veno-constriction mediated by the carotid sinus baroreceptor reflex system on overall circulatory homeostasis and in the regulation of cardiac output. Our proposed experiments test the overall hypothesis that alterations in venous capacitance function and arterial resistance by the carotid sinus baroreceptor reflex system are an important determinant of the cardiac output and blood pressure response seen in astronauts after returning to earth from long term exposure to microgravity. This hypothesis is important to our overall understanding of circulatory adjustments made during long term space flight. It also provides a framework for investigating counter measures to reduce the incidence of orthostatic hypotension caused by an attenuation of cardiac output. We continue to use hind limb unweighted (HLU) rat model to simulate the patho physiological effects as they relate to cardiovascular deconditioning in microgravity. We have used this model to address the hypothesis that microgravity induced cardiovascular deconditioning results in impaired vascular responses and that these impaired vascular responses result from abnormal alpha-1 AR signaling. The impaired vascular reactivity results in attenuated blood pressure and cardiac output responses to an

Simulation of Distributed PV Power Output in Oahu Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lave, Matthew Samuel

2016-08-01

Distributed solar photovoltaic (PV) power generation in Oahu has grown rapidly since 2008. For applications such as determining the value of energy storage, it is important to have PV power output timeseries. Since these timeseries of not typically measured, here we produce simulated distributed PV power output for Oahu. Simulated power output is based on (a) satellite-derived solar irradiance, (b) PV permit data by neighborhood, and (c) population data by census block. Permit and population data was used to model locations of distributed PV, and irradiance data was then used to simulate power output. PV power output simulations are presentedmore » by sub-neighborhood polygons, neighborhoods, and for the whole island of Oahu. Summary plots of annual PV energy and a sample week timeseries of power output are shown, and a the files containing the entire timeseries are described.« less

Phenotyping Cardiac Arrest: Bench and Bedside Characterization of Brain and Heart Injury Based on Etiology.

PubMed

Uray, Thomas; Lamade, Andrew; Elmer, Jonathan; Drabek, Tomas; Stezoski, Jason P; Missé, Amalea; Janesko-Feldman, Keri; Garman, Robert H; Chen, Niel; Kochanek, Patrick M; Dezfulian, Cameron; Callaway, Clifton W; Doshi, Ankur A; Frisch, Adam; Guyette, Francis X; Reynolds, Josh C; Rittenberger, Jon C

2018-06-01

Cardiac arrest etiology may be an important source of between-patient heterogeneity, but the impact of etiology on organ injury is unknown. We tested the hypothesis that asphyxial cardiac arrest results in greater neurologic injury than cardiac etiology cardiac arrest (ventricular fibrillation cardiac arrest), whereas ventricular fibrillation cardiac arrest results in greater cardiovascular dysfunction after return of spontaneous circulation. Prospective observational human and randomized animal study. University laboratory and ICUs. Five-hundred forty-three cardiac arrest patients admitted to ICU. Seventy-five male Sprague-Dawley rats. We examined neurologic and cardiovascular injury in Isoflurane-anesthetized rat cardiac arrest models matched by ischemic time. Hemodynamic and neurologic outcomes were assessed after 5 minutes no flow asphyxial cardiac arrest or ventricular fibrillation cardiac arrest. Comparison was made to injury patterns observed after human asphyxial cardiac arrest or ventricular fibrillation cardiac arrest. In rats, cardiac output (20 ± 10 vs 45 ± 9 mL/min) and pH were lower and lactate higher (9.5 ± 1.0 vs 6.4 ± 1.3 mmol/L) after return of spontaneous circulation from ventricular fibrillation cardiac arrest versus asphyxial cardiac arrest (all p < 0.01). Asphyxial cardiac arrest resulted in greater early neurologic deficits, 7-day neuronal loss, and reduced freezing time (memory) after conditioned fear (all p < 0.05). Brain antioxidant reserves were more depleted following asphyxial cardiac arrest. In adjusted analyses, human ventricular fibrillation cardiac arrest was associated with greater cardiovascular injury based on peak troponin (7.8 ng/mL [0.8-57 ng/mL] vs 0.3 ng/mL [0.0-1.5 ng/mL]) and ejection fraction by echocardiography (20% vs 55%; all p < 0.0001), whereas asphyxial cardiac arrest was associated with worse early neurologic injury and poor functional outcome at hospital discharge (n = 46 [18%] vs 102 [44%]; p < 0.0001). Most

Electrochemistry in Organisms: Electron Flow and Power Output

ERIC Educational Resources Information Center

Chirpich, Thomas P.

1975-01-01

Presents a series of calculations, appropriate for the freshman level, to determine the flow of electrons to oxygen along the electron transport chain. States that living organisms resemble fuel cells and develops calculations for determining power output. (GS)

Energy Harvesting by Subcutaneous Solar Cells: A Long-Term Study on Achievable Energy Output.

PubMed

Bereuter, L; Williner, S; Pianezzi, F; Bissig, B; Buecheler, S; Burger, J; Vogel, R; Zurbuchen, A; Haeberlin, A

2017-05-01

Active electronic implants are powered by primary batteries, which induces the necessity of implant replacement after battery depletion. This causes repeated interventions in a patients' life, which bears the risk of complications and is costly. By using energy harvesting devices to power the implant, device replacements may be avoided and the device size may be reduced dramatically. Recently, several groups presented prototypes of implants powered by subcutaneous solar cells. However, data about the expected real-life power output of subcutaneously implanted solar cells was lacking so far. In this study, we report the first real-life validation data of energy harvesting by subcutaneous solar cells. Portable light measurement devices that feature solar cells (cell area = 3.6 cm 2 ) and continuously measure a subcutaneous solar cell's output power were built. The measurement devices were worn by volunteers in their daily routine in summer, autumn and winter. In addition to the measured output power, influences such as season, weather and human activity were analyzed. The obtained mean power over the whole study period was 67 µW (=19 µW cm -2 ), which is sufficient to power e.g. a cardiac pacemaker.

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

PubMed Central

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

2012-01-01

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

MitoQ administration prevents endotoxin-induced cardiac dysfunction.

PubMed

Supinski, G S; Murphy, M P; Callahan, L A

2009-10-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6'-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg x kg(-1) x day(-1)), saline + MitoQ (500 microM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction.

Cardiac effects of 3-iodothyronamine: a new aminergic system modulating cardiac function.

PubMed

Chiellini, Grazia; Frascarelli, Sabina; Ghelardoni, Sandra; Carnicelli, Vittoria; Tobias, Sandra C; DeBarber, Andrea; Brogioni, Simona; Ronca-Testoni, Simonetta; Cerbai, Elisabetta; Grandy, David K; Scanlan, Thomas S; Zucchi, Riccardo

2007-05-01

3-Iodothyronamine T1AM is a novel endogenous thyroid hormone derivative that activates the G protein-coupled receptor known as trace anime-associated receptor 1 (TAAR1). In the isolated working rat heart and in rat cardiomyocytes, T1AM produced a reversible, dose-dependent negative inotropic effect (e.g., 27+/-5, 51+/-3, and 65+/-2% decrease in cardiac output at 19, 25, and 38 microM concentration, respectively). An independent negative chronotropic effect was also observed. The hemodynamic effects of T1AM were remarkably increased in the presence of the tyrosine kinase inhibitor genistein, whereas they were attenuated in the presence of the tyrosine phosphatase inhibitor vanadate. No effect was produced by inhibitors of protein kinase A, protein kinase C, calcium-calmodulin kinase II, phosphatidylinositol-3-kinase, or MAP kinases. Tissue cAMP levels were unchanged. In rat ventricular tissue, Western blot experiments with antiphosphotyrosine antibodies showed reduced phosphorylation of microsomal and cytosolic proteins after perfusion with synthetic T1AM; reverse transcriptase-polymerase chain reaction experiments revealed the presence of transcripts for at least 5 TAAR subtypes; specific and saturable binding of [125I]T1AM was observed, with a dissociation constant in the low micromolar range (5 microM); and endogenous T1AM was detectable by tandem mass spectrometry. In conclusion, our findings provide evidence for the existence of a novel aminergic system modulating cardiac function.

Using cardiovascular imaging modalities to determine cardiac disorders before starting sports activities.

PubMed

Ceylan, Özgür; Meşe, Timur; Gürsu, Alper Hazım

2017-03-01

We re-examined children who had previously been declared eligible to participate in competitive sports activities for cardiac disorders, using cardiac investigation protocol. Total of 250 children (224 males [89.6%], and 26 females [10.4%]) between the ages of 8 and 17 years who had just started or were already engaged in sports activities were included in the study. Participants had detailed physical examination evaluated by a pediatric cardiologist. Those with findings suggesting cardiac disorder in their history and/or physical examinations, and/or 12-channel electrocardiography (ECG) were examined with echocardiography (ECHO), 24-hour Holter monitoring, and exercise test. Mean duration of participation in sports activities was 13 months. Among all, 10.4% of the children had abnormalities on ECG. ECHO demonstrated cardiomyopathy in 1, mitral valve prolapse in 2, tricuspid insufficiency in 2, and mitral insufficiency in 1 participant. Holter monitoring revealed non-sustained ventricular tachycardia attacks in 1, and supraventricular tachycardia in another child. Three were ultimately disqualified from partaking in competitive sports. Sports and medical communities must work together to establish study protocols to prevent sudden death related to sports and to make these activities safer for athletes. Pediatric cardiology consultation for young athletes before they start sports activities is needed.

Non-invasive measurement of cardiac output in children with repaired coarctation of the aorta using electrical cardiometry compared to transthoracic Doppler echocardiography.

PubMed

Altamirano-Diaz, Luis; Welisch, Eva; Dempsey, Adam A; Park, Teresa Sohee; Grattan, Michael; Norozi, Kambiz

2018-05-17

To evaluate the equivalence of the ICON ® electrical cardiometry (EC) haemodynamic monitor to measure cardiac output (CO) relative to transthoracic Doppler echocardiography (TTE) in paediatric patients with repaired coarctation of the aorta (CoA). A group of n  =  28 CoA patients and n  =  27 matched controls were enrolled. EC and TTE were performed synchronously on each participant and CO measurements compared using linear regression and Bland-Altman analysis. The CoA group was further subdivided into two groups, with n  =  10 and without n  =  18 increased left ventricular outflow tract velocity (iLVOTv) for comparison. CO measurements from EC and TTE in controls showed a strong correlation (R  =  0.80, p  <  0.001) and an acceptable percentage error (PE) of 28.1%. However, combining CoA and control groups revealed a moderate correlation (R  =  0.57, p  <  0.001) and a poor PE (44.2%). We suspected that the CO in a subset of CoA participants with iLVOTv was overestimated by TTE. Excluding the iLVOTv CoA participants improved the correlation (R  =  0.77, p  <  0.001) and resulted in an acceptable PE of 31.2%. CO measurements in paediatric CoA patients in the absence of iLVOTv are clinically equivalent between EC and TTE. The presence of iLVOTv may impact the accuracy of CO measurement by TTE, but not EC.

Cardiac myofibrillar contractile properties during the progression from hypertension to decompensated heart failure.

PubMed

Hanft, Laurin M; Emter, Craig A; McDonald, Kerry S

2017-07-01

Heart failure arises, in part, from a constellation of changes in cardiac myocytes including remodeling, energetics, Ca 2+ handling, and myofibrillar function. However, little is known about the changes in myofibrillar contractile properties during the progression from hypertension to decompensated heart failure. The aim of the present study was to provide a comprehensive assessment of myofibrillar functional properties from health to heart disease. A rodent model of uncontrolled hypertension was used to test the hypothesis that myocytes in compensated hearts exhibit increased force, higher rates of force development, faster loaded shortening, and greater power output; however, with progression to overt heart failure, we predicted marked depression in these contractile properties. We assessed contractile properties in skinned cardiac myocyte preparations from left ventricles of Wistar-Kyoto control rats and spontaneous hypertensive heart failure (SHHF) rats at ~3, ~12, and >20 mo of age to evaluate the time course of myofilament properties associated with normal aging processes compared with myofilaments from rats with a predisposition to heart failure. In control rats, the myofilament contractile properties were virtually unchanged throughout the aging process. Conversely, in SHHF rats, the rate of force development, loaded shortening velocity, and power all increased at ~12 mo and then significantly fell at the >20-mo time point, which coincided with a decrease in left ventricular fractional shortening. Furthermore, these changes occurred independent of changes in β-myosin heavy chain but were associated with depressed phosphorylation of myofibrillar proteins, and the fall in loaded shortening and peak power output corresponded with the onset of clinical signs of heart failure. NEW & NOTEWORTHY This novel study systematically examined the power-generating capacity of cardiac myofilaments during the progression from hypertension to heart disease. Previously

Vinpocetine Attenuates Pathological Cardiac Remodeling by Inhibiting Cardiac Hypertrophy and Fibrosis.

PubMed

Wu, Mei-Ping; Zhang, Yi-Shuai; Xu, Xiangbin; Zhou, Qian; Li, Jian-Dong; Yan, Chen

2017-04-01

Pathological cardiac remodeling, characterized by cardiac hypertrophy and fibrosis, is a pathological feature of many cardiac disorders that leads to heart failure and cardiac arrest. Vinpocetine, a derivative of the alkaloid vincamine, has been used for enhancing cerebral blood flow to treat cognitive impairment. However, its role in pathological cardiac remodeling remains unknown. The aim of this study is to examine the effect of vinpocetine on pathological cardiac remodeling induced by chronic stimulation with angiotensin II (Ang II). Mice received Ang II infusion via osmotic pumps in the presence of vehicle or vinpocetine. Cardiac hypertrophy and fibrosis were assessed by morphological, histological, and biochemical analyses. Mechanistic studies were carried out in vitro with isolated mouse adult cardiac myocytes and fibroblasts. We showed that chronic Ang II infusion caused cardiac hypertrophy and fibrosis, which were all significantly attenuated by systemic administration of vinpocetine. In isolated adult mouse cardiomyocytes, vinpocetine suppressed Ang II-stimulated myocyte hypertrophic growth. In cultured cardiac fibroblasts, vinpocetine suppressed TGFβ-induced fibroblast activation and matrix gene expression, consistent with its effect in attenuating cardiac fibrosis. The effects of vinpocetine on cardiac myocyte hypertrophy and fibroblast activation are likely mediated by targeting cyclic nucleotide phosphodiesterase 1 (PDE1). Our results reveal a novel protective effect of vinpocetine in attenuating pathological cardiac remodeling through suppressing cardiac myocyte hypertrophic growth and fibroblast activation and fibrotic gene expression. These studies may also shed light on developing novel therapeutic agents for antagonizing pathological cardiac remodeling.

3D bioprinted functional and contractile cardiac tissue constructs

PubMed Central

Wang, Zhan; Lee, Sang Jin; Cheng, Heng-Jie; Yoo, James J.; Atala, Anthony

2018-01-01

Bioengineering of a functional cardiac tissue composed of primary cardiomyocytes has great potential for myocardial regeneration and in vitro tissue modeling. However, its applications remain limited because the cardiac tissue is a highly organized structure with unique physiologic, biomechanical, and electrical properties. In this study, we undertook a proof-of-concept study to develop a contractile cardiac tissue with cellular organization, uniformity, and scalability by using three-dimensional (3D) bioprinting strategy. Primary cardiomyocytes were isolated from infant rat hearts and suspended in a fibrin-based bioink to determine the priting capability for cardiac tissue engineering. This cell-laden hydrogel was sequentially printed with a sacrificial hydrogel and a supporting polymeric frame through a 300-μm nozzle by pressured air. Bioprinted cardiac tissue constructs had a spontaneous synchronous contraction in culture, implying in vitro cardiac tissue development and maturation. Progressive cardiac tissue development was confirmed by immunostaining for α-actinin and connexin 43, indicating that cardiac tissues were formed with uniformly aligned, dense, and electromechanically coupled cardiac cells. These constructs exhibited physiologic responses to known cardiac drugs regarding beating frequency and contraction forces. In addition, Notch signaling blockade significantly accelerated development and maturation of bioprinted cardiac tissues. Our results demonstrated the feasibility of bioprinting functional cardiac tissues that could be used for tissue engineering applications and pharmaceutical purposes. PMID:29452273

Determinants and prognostic implications of cardiac troponin T measured by a sensitive assay in type 2 diabetes mellitus.

PubMed

Hallén, Jonas; Johansen, Odd Erik; Birkeland, Kåre I; Gullestad, Lars; Aakhus, Svend; Endresen, Knut; Tjora, Solve; Jaffe, Allan S; Atar, Dan

2010-09-15

The cardiac troponins are biomarkers used for diagnosis of myocardial injury. They are also powerful prognostic markers in many diseases and settings. Recently introduced high-sensitivity assays indicate that chronic cardiac troponin elevations are common in response to cardiovascular (CV) morbidity. Type 2 diabetes mellitus (T2DM) confers a high risk of CV disease, but little is known about chronic cardiac troponin elevations in diabetic subjects. Accordingly, we aimed to understand the prevalence, determinants, and prognostic implications of cardiac troponin T (cTnT) elevations measured with a high-sensitivity assay in patients with T2DM. cTnT was measured in stored, frozen serum samples from 124 subjects enrolled in the Asker and Bærum Cardiovascular Diabetes trial at baseline and at 2-year follow-up, if available (96 samples available). Results were analyzed in relation to baseline variables, hospitalizations, and group assignment (multifactorial intensive versus conventional diabetes care for lowering CV risk). One-hundred thirteen (90%) had detectable cTnT at baseline and of those, 22 (18% of the total population) subjects had values above the 99th percentile for healthy controls (13.5 ng/L). Levels at baseline were associated with conventional CV risk factors (age, renal function, gender). There was a strong correlation between cTnT levels at the two time-points (r=0.92, p>0.001). Risk for hospitalizations during follow-up increased step-wise by quartiles of hscTnT measured at baseline (p=0.058). Elevations of cTnT above the 99th percentile measured by a highly sensitive assay were encountered frequently in a population of T2DM patients. cTnT levels appeared to be stable over time and associated with conventional CV risk factors. Although a clear trend was present, no statistically robust associations with adverse outcomes could be found.

Evaluation of the pulse-contour method of determining stroke volume in man.

NASA Technical Reports Server (NTRS)

Alderman, E. L.; Branzi, A.; Sanders, W.; Brown, B. W.; Harrison, D. C.

1972-01-01

The pulse-contour method for determining stroke volume has been employed as a continuous rapid method of monitoring the cardiovascular status of patients. Twenty-one patients with ischemic heart disease and 21 patients with mitral valve disease were subjected to a variety of hemodynamic interventions. The pulse-contour estimations, using three different formulas derived by Warner, Kouchoukos, and Herd, were compared with indicator-dilution outputs. A comparison of the results of the two methods for determining stroke volume yielded correlation coefficients ranging from 0.59 to 0.84. The better performing Warner formula yielded a coefficient of variation of about 20%. The type of hemodynamic interventions employed did not significantly affect the results using the pulse-contour method. Although the correlation of the pulse-contour and indicator-dilution stroke volumes is high, the coefficient of variation is such that small changes in stroke volume cannot be accurately assessed by the pulse-contour method. However, the simplicity and rapidity of this method compared to determination of cardiac output by Fick or indicator-dilution methods makes it a potentially useful adjunct for monitoring critically ill patients.

Measuring the mechanical efficiency of a working cardiac muscle sample at body temperature using a flow-through calorimeter.

PubMed

Taberner, Andrew J; Johnston, Callum M; Pham, Toan; June-Chiew Han; Ruddy, Bryan P; Loiselle, Denis S; Nielsen, Poul M F

2015-08-01

We have developed a new `work-loop calorimeter' that is capable of measuring, simultaneously, the work-done and heat production of isolated cardiac muscle samples at body temperature. Through the innovative use of thermoelectric modules as temperature sensors, the development of a low-noise fluid-flow system, and implementation of precise temperature control, the heat resolution of this device is 10 nW, an improvement by a factor of ten over previous designs. These advances have allowed us to conduct the first flow-through measurements of work output and heat dissipation from cardiac tissue at body temperature. The mechanical efficiency is found to vary with peak stress, and reaches a peak value of approximately 15 %, a figure similar to that observed in cardiac muscle at lower temperatures.

Optimization of Electrical Stimulation Parameters for Cardiac Tissue Engineering

PubMed Central

Tandon, Nina; Marsano, Anna; Maidhof, Robert; Wan, Leo; Park, Hyoungshin; Vunjak-Novakovic, Gordana

2010-01-01

In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile cardiac tissue constrcuts. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation, to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, and were thus used in tissue engineering studies. Cardiac tissues stimulated at 3V/cm amplitude and 3Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43, and the best developed contractile behavior. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering. PMID:21604379

Residual gravimetric method to measure nebulizer output.

PubMed

Vecellio None, Laurent; Grimbert, Daniel; Bordenave, Joelle; Benoit, Guy; Furet, Yves; Fauroux, Brigitte; Boissinot, Eric; De Monte, Michele; Lemarié, Etienne; Diot, Patrice

2004-01-01

The aim of this study was to assess a residual gravimetric method based on weighing dry filters to measure the aerosol output of nebulizers. This residual gravimetric method was compared to assay methods based on spectrophotometric measurement of terbutaline (Bricanyl, Astra Zeneca, France), high-performance liquid chromatography (HPLC) measurement of tobramycin (Tobi, Chiron, U.S.A.), and electrochemical measurements of NaF (as defined by the European standard). Two breath-enhanced jet nebulizers, one standard jet nebulizer, and one ultrasonic nebulizer were tested. Output produced by the residual gravimetric method was calculated by weighing the filters both before and after aerosol collection and by filter drying corrected by the proportion of drug contained in total solute mass. Output produced by the electrochemical, spectrophotometric, and HPLC methods was determined after assaying the drug extraction filter. The results demonstrated a strong correlation between the residual gravimetric method (x axis) and assay methods (y axis) in terms of drug mass output (y = 1.00 x -0.02, r(2) = 0.99, n = 27). We conclude that a residual gravimetric method based on dry filters, when validated for a particular agent, is an accurate way of measuring aerosol output.

Cardiac troponins--Translational biomarkers in cardiology: Theory and practice of cardiac troponin high-sensitivity assays.

PubMed

Adamcova, Michaela; Popelova-Lencova, Olga; Jirkovsky, Eduard; Simko, Fedor; Gersl, Vladimir; Sterba, Martin

2016-01-01

Tn is a unique translational biomarker in cardiology whose potential has not been diminished in the new era of high sensitive assays. cTns can be valuable markers in cardiac diseases as well as in infectious diseases and respiratory diseases. Furthermore, the role of cTns is growing in the routine evaluation of cardioxicity and in determining the efficacy/safety ratio of novel cardioprotective strategies in clinical settings. cTns can detect myocardial injury not only in a wide spectrum of laboratory animals in experimental studies in vivo, but also in isolated heart models or cardiomyocytes in vitro. The crucial issue regarding the cross-species usage of cardiac troponin investigation remains the choice of cardiac troponin testing. This review summarizes the recent proteomic data on aminoacid sequences of cTnT and cTnI in various species, as well as selected analytical characteristics of human cardiac troponin high-sensitivity assays. Due to the highly phylogenetically conserved structure of troponins, the same bioindicator can be investigated using the same method in both clinical and experimental cardiology, thus contributing to a better understanding of the pathogenesis of cardiac diseases as well as to increased effectiveness of troponin use in clinical practice. Measuring cardiac troponins using commercially available human high-sensitivity cardiac troponin tests with convenient antibodies selected on the basis of adequate proteomic knowledge can solve many issues which would otherwise be difficult to address in clinical settings for various ethical and practical reasons. Our survey could help elaborate the practical guidelines for optimizing the choice of cTns assay in cardiology. © 2016 International Union of Biochemistry and Molecular Biology.

Vinpocetine Attenuates Pathological Cardiac Remodeling by Inhibiting Cardiac Hypertrophy and Fibrosis

PubMed Central

Wu, Mei-ping; Zhang, Yi-shuai; Xu, Xiangbin; Zhou, Qian

2017-01-01

Purpose Pathological cardiac remodeling, characterized by cardiac hypertrophy and fibrosis, is a pathological feature of many cardiac disorders that leads to heart failure and cardiac arrest. Vinpocetine, a derivative of the alkaloid vincamine, has been used for enhancing cerebral blood flow to treat cognitive impairment. However, its role in pathological cardiac remodeling remains unknown. The aim of this study is to examine the effect of vinpocetine on pathological cardiac remodeling induced by chronic stimulation with angiotensin II (Ang II). Methods Mice received Ang II infusion via osmotic pumps in the presence of vehicle or vinpocetine. Cardiac hypertrophy and fibrosis were assessed by morphological, histological, and biochemical analyses. Mechanistic studies were carried out in vitro with isolated mouse adult cardiac myocytes and fibroblasts. Results We showed that chronic Ang II infusion caused cardiac hypertrophy and fibrosis, which were all significantly attenuated by systemic administration of vinpocetine. In isolated adult mouse cardiomyocytes, vinpocetine suppressed Ang II-stimulated myocyte hypertrophic growth. In cultured cardiac fibroblasts, vinpocetine suppressed TGFβ-induced fibroblast activation and matrix gene expression, consistent with its effect in attenuating cardiac fibrosis. The effects of vinpocetine on cardiac myocyte hypertrophy and fibroblast activation are likely mediated by targeting cyclic nucleotide phosphodiesterase 1 (PDE1). Conclusions Our results reveal a novel protective effect of vinpocetine in attenuating pathological cardiac remodeling through suppressing cardiac myocyte hypertrophic growth and fibroblast activation and fibrotic gene expression. These studies may also shed light on developing novel therapeutic agents for antagonizing pathological cardiac remodeling. PMID:28321644

The Diagnostic Value of Troponin T Level in the Determination of Cardiac Damage in Perinatal Asphyxia Newborns.

PubMed

Yildirim, Ali; Ozgen, Fatih; Ucar, Birsen; Alatas, Ozkan; Tekin, Neslihan; Kilic, Zubeyir

2016-01-01

Perinatal asphyxia is a clinical condition which results from oxygen deprivation of the fetus or newborn and the breakdown of perfusion in various organs. The aim of this study was to evaluate and compare troponin T levels over time as a marker of cardiac injury in cases of perinatal asphyxia and healthy newborns. The study included a total of 30 newborns diagnosed with perinatal asphyxia with a gestational age of 32-41 weeks, based on the last menstruation date, and 30 healthy newborns with a gestational age of 34-40 weeks, as the control group. Levels of troponin T and creatinin kinase MB were recorded for all participants. No difference was determined between the groups in terms of gestational age, manner of birth, electrocardiographic findings, and PaO2 and PaCO2 values. The umbilical artery pH levels and bicarbonate levels in the study group were found to be statistically lower than those in the control group (p < 0.001). The troponin T and creatinin kinase MB levels in the patients in the study group were higher than those within the control group, at all times. The periods when specificity and sensitivity were highest together for troponin T were the 12th and 24th h. Specificity for troponin T reached the highest value at the 24th h and sensitivity reached the highest value in the cord blood. A positive correlation was found between the troponin T and creatinin kinase MB values at the 6th and 12th h. However, no correlation could be found in the blood between the serum troponin T and creatinin kinase MB levels at the 3rd and 24th h. The troponin T level is a useful test for showing cardiac damage in hypoxic patients in the neonatal period. The sensitivity and specificity of cardiac specific troponin T levels in detecting cardiac damage are much higher according to telecardiography and electrocardiography, while the implementation of the method is simple.

Cardiac surgery-associated acute kidney injury.

PubMed

Vives, Marc; Wijeysundera, Duminda; Marczin, Nandor; Monedero, Pablo; Rao, Vivek

2014-05-01

Acute kidney injury develops in up to 30% of patients who undergo cardiac surgery, with up to 3% of patients requiring dialysis. The requirement for dialysis after cardiac surgery is associated with an increased risk of infection, prolonged stay in critical care units and long-term need for dialysis. The development of acute kidney injury is independently associated with substantial short- and long-term morbidity and mortality. Its pathogenesis involves multiple pathways. Haemodynamic, inflammatory, metabolic and nephrotoxic factors are involved and overlap each other leading to kidney injury. Clinical studies have identified predictors for cardiac surgery-associated acute kidney injury that can be used effectively to determine the risk for acute kidney injury in patients undergoing cardiac surgery. High-risk patients can be targeted for renal protective strategies. Nonetheless, there is little compelling evidence from randomized trials supporting specific interventions to protect or prevent acute kidney injury in cardiac surgery patients. Several strategies have shown some promise, including less invasive procedures in those at greatest risk, natriuretic peptide, fenoldopam, preoperative hydration, preoperative optimization of anaemia and postoperative early use of renal replacement therapy. The efficacy of larger-scale trials remains to be confirmed.

Isometric exercise: cardiovascular responses in normal and cardiac populations.

PubMed

Hanson, P; Nagle, F

1987-05-01

Isometric exercise produces a characteristic pressor increase in blood pressure which may be important in maintaining perfusion of muscle during sustained contraction. This response is mediated by combined central and peripheral afferent input to medullary cardiovascular centers. In normal individuals the increase in blood pressure is mediated by a rise in cardiac output with little or no change in systemic vascular resistance. However, the pressor response is also maintained during pharmacologic blockade or surgical denervation by increasing systemic vascular resistance. Left ventricular function is normally maintained or improves in normal subjects and cardiac patients with mild impairment of left ventricular contractility. Patients with poor left ventricular function may show deterioration during isometric exercise, although this pattern of response is difficult to predict from resting studies. Recent studies have shown that patients with uncomplicated myocardial infarction can perform submaximum isometric exercise such as carrying weights in the range of 30 to 50 lb without difficulty or adverse responses. In addition, many patients who show ischemic ST depression or angina during dynamic exercise may have a reduced ischemic response during isometric or combined isometric and dynamic exercise. Isometric exercises are frequently encountered in activities of daily living and many occupational tasks. Cardiac patients should be gradually exposed to submaximum isometric training in supervised cardiac rehabilitation programs. Specific job tasks that require isometric or combined isometric and dynamic activities may be evaluated by work simulation studies. This approach to cardiac rehabilitation may facilitate patients who wish to return to a job requiring frequent isometric muscle contraction. Finally, there is a need for additional research on the long-term effects of isometric exercise training on left ventricular hypertrophy and performance. The vigorous training

Increase in cardiac myosin heavy-chain (MyHC) alpha protein isoform in hibernating ground squirrels, with echocardiographic visualization of ventricular wall hypertrophy and prolonged contraction

PubMed Central

Nelson, O. Lynne; Rourke, Bryan C.

2013-01-01

SUMMARY Deep hibernators such as golden-mantled ground squirrels (Callospermophilus lateralis) have multiple challenges to cardiac function during low temperature torpor and subsequent arousals. As heart rates fall from over 300 beats min−1 to less than 10, chamber dilation and reduced cardiac output could lead to congestive myopathy. We performed echocardiography on a cohort of individuals prior to and after several months of hibernation. The left ventricular chamber exhibited eccentric and concentric hypertrophy during hibernation and thus calculated ventricular mass was ~30% greater. Ventricular ejection fraction was mildly reduced during hibernation but stroke volumes were greater due to the eccentric hypertrophy and dramatically increased diastolic filling volumes. Globally, the systolic phase in hibernation was ~9.5 times longer, and the diastolic phase was 28× longer. Left atrial ejection generally was not observed during hibernation. Atrial ejection returned weakly during early arousal. Strain echocardiography assessed the velocity and total movement distance of contraction and relaxation for regional ventricular segments in active and early arousal states. Myocardial systolic strain during early arousal was significantly greater than the active state, indicating greater total contractile movement. This mirrored the increased ventricular ejection fraction noted with early arousal. However, strain rates were slower during early arousal than during the active period, particularly systolic strain, which was 33% of active, compared with the rate of diastolic strain, which was 67% of active. As heart rate rose during the arousal period, myocardial velocities and strain rates also increased; this was matched closely by cardiac output. Curiously, though heart rates were only 26% of active heart rates during early arousal, the cardiac output was nearly 40% of the active state, suggesting an efficient pumping system. We further analyzed proportions of cardiac

MitoQ administration prevents endotoxin-induced cardiac dysfunction

PubMed Central

Murphy, M. P.; Callahan, L. A.

2009-01-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6′-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg·kg−1·day−1), saline + MitoQ (500 μM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction. PMID:19657095

Renal perfusion index reflects cardiac systolic function in chronic cardio-renal syndrome.

PubMed

Lubas, Arkadiusz; Ryczek, Robert; Kade, Grzegorz; Niemczyk, Stanisław

2015-04-17

Cardiac dysfunction can modify renal perfusion, which is crucial to maintain sufficient kidney tissue oxygenation. Renal cortex perfusion assessed by dynamic ultrasound method is related both to renal function and cardiac hemodynamics. The aim of the study was to test the hypothesis that Renal Perfusion Index (RPI) can more closely reflect cardiac hemodynamics and differentiate etiology of chronic cardio-renal syndrome. Twenty-four patients with hypertension and chronic kidney disease (CKD) at 2-4 stage (12 with hypertensive nephropathy and 12 with CKD prior to hypertension) were enrolled in the study. Blood tests, 24-h ABPM, echocardiography, and ultrasonography with estimation of Total renal Cortical Perfusion intensity and Renal Perfusion Index (RPI) were performed. In the group of all patients, RPI correlated with left ventricular stoke volume (LVSV), and cardiac index, but not with markers of renal function. In multiple stepwise regression analysis CKD-EPI(Cys-Cr) (b=-0.360), LVSV (b=0.924) and MAP (b=0.376) together independently influenced RPI (R2=0.74; p<0.0001). RPI<0.567 allowed for the identification of patients with chronic cardio-renal syndrome with sensitivity of 41.7% and specificity of 83.3%. Renal perfusion index relates more strongly to cardiac output than to renal function, and could be helpful in recognizing chronic cardio-renal syndrome. Applicability of RPI in diagnosing early abnormalities in the cardio-renal axis requires further investigation.

[Role of cardiac magnetic resonance in cardiac involvement of Fabry disease].

PubMed

Serra, Viviana M; Barba, Miguel Angel; Torrá, Roser; Pérez De Isla, Leopoldo; López, Mónica; Calli, Andrea; Feltes, Gisela; Torras, Joan; Valverde, Victor; Zamorano, José L

2010-09-04

Fabry disease is a hereditary disorder. Clinical manifestations are multisystemic. The majority of the patients remain undiagnosed until late in life, when alterations could be irreversible. Early detection of cardiac symptoms is of major interest in Fabry's disease (FD) in order to gain access to enzyme replacement therapy. Echo-Doppler tissular imaging (TDI) has been used as a cardiologic early marker in FD. This study is intended to determine whether the cardiac magnetic resonance is as useful tool as TDI for the early detection of cardiac affectation in FD. Echocardiography, tissue Doppler and Cardio magnetic resonance was performed in 20 patients with confirmed Fabry Disease. Left ventricular hypertrophy was defined as septum and left ventricular posterior wall thickness ≥12 mm. An abnormal TDI velocity was defined as (Sa), (Ea) and/or (Aa) velocities <8 cm/s at either the septal or lateral corner. Late phase gadolinium-enhanced images sequences were obtained using magnetic resonance. Twenty patients included in the study were divided into three groups: 1. Those without left ventricular hypertrophy nor tissue Doppler impairment 2. Those without left ventricular hypertrophy and tissue Doppler impairment 3. Those with left ventricular hypertrophy and Tissue Doppler impairment. Late gadolinium enhancement was found in only one patient, who has already altered DTI and LVH. Tissue Doppler imaging (TDI) is the only diagnostic tool able to provide early detection of cardiac affectation in patients with FD. Magnetic resonance provides information of the disease severity in patients with LVH, but can not be used as an early marker of cardiac disease in patients with FD. However MRI could be of great value for diagnostic stratification. Copyright © 2009 Elsevier España, S.L. All rights reserved.

Cardiorespiratory responses to orthostasis and the effects of propranolol

NASA Technical Reports Server (NTRS)

Loeppky, J. A.

1975-01-01

Cardiac output and gas exchange were determined serially using the single-breath method of Kim et al. before, during, and after orthostasis on six subjects after beta-adrenergic blockage and in duplicate controls. In the latter, heart rate increased and pulse pressure dropped immediately on tilting to 60 deg and remained stable while cardiac output and stroke volume declined gradually over 21 min upright. On propranolol, heart rate was 10 bpm lower supine and 20 bpm less at 60 deg but cardiac output was only slightly lower before and following tilt-up. However, after 15 min upright, stroke volume and cardiac output recovered on propranolol exceeding the controls after 21 min without change in heart rate. Returning to supine, heart rate dropped in all tests with a transitory increase in stroke volume, cardiac output and arteriovenous O2 difference. At the same time, apparent O2 uptake increased temporarily, reflecting the return of pooled venous blood to the lungs. Orthostatic tolerance did not appear to be affected by beta-adrenergic blockade.

Computational Chemical Imaging for Cardiovascular Pathology: Chemical Microscopic Imaging Accurately Determines Cardiac Transplant Rejection

PubMed Central

Tiwari, Saumya; Reddy, Vijaya B.; Bhargava, Rohit; Raman, Jaishankar

2015-01-01

Rejection is a common problem after cardiac transplants leading to significant number of adverse events and deaths, particularly in the first year of transplantation. The gold standard to identify rejection is endomyocardial biopsy. This technique is complex, cumbersome and requires a lot of expertise in the correct interpretation of stained biopsy sections. Traditional histopathology cannot be used actively or quickly during cardiac interventions or surgery. Our objective was to develop a stain-less approach using an emerging technology, Fourier transform infrared (FT-IR) spectroscopic imaging to identify different components of cardiac tissue by their chemical and molecular basis aided by computer recognition, rather than by visual examination using optical microscopy. We studied this technique in assessment of cardiac transplant rejection to evaluate efficacy in an example of complex cardiovascular pathology. We recorded data from human cardiac transplant patients’ biopsies, used a Bayesian classification protocol and developed a visualization scheme to observe chemical differences without the need of stains or human supervision. Using receiver operating characteristic curves, we observed probabilities of detection greater than 95% for four out of five histological classes at 10% probability of false alarm at the cellular level while correctly identifying samples with the hallmarks of the immune response in all cases. The efficacy of manual examination can be significantly increased by observing the inherent biochemical changes in tissues, which enables us to achieve greater diagnostic confidence in an automated, label-free manner. We developed a computational pathology system that gives high contrast images and seems superior to traditional staining procedures. This study is a prelude to the development of real time in situ imaging systems, which can assist interventionists and surgeons actively during procedures. PMID:25932912

Comparison of plasma cardiac troponin I concentrations among dogs with cardiac hemangiosarcoma, noncardiac hemangiosarcoma, other neoplasms, and pericardial effusion of nonhemangiosarcoma origin.

PubMed

Chun, Ruthanne; Kellihan, Heidi B; Henik, Rosemary A; Stepien, Rebecca L

2010-10-01

To determine whether plasma cardiac troponin I (cTnl) concentrations can be used to identify cardiac involvement in dogs with hemangiosarcoma, exclude cardiac hemangiosarcoma in dogs with noncardiac hemangiosarcoma, and identify cardiac hemangiosarcoma in dogs with pericardial effusion. Cohort study. 57 dogs (18 with confirmed [5 dogs] or suspected [13] cardiac hemangiosarcoma, 14 with confirmed hemangiosarcoma involving sites other than the heart [noncardiac hemangiosarcoma], 10 with pericardial effusion not caused by hemangiosarcoma, and 15 with noncardiac nonhemangiosarcoma neoplasms). Plasma cTnl concentration was measured, and thoracic radiography, abdominal ultrasonography, and echocardiography were performed in each dog. The cTnl concentration was compared among groups. Median plasma cTnl concentration in dogs with cardiac hemangiosarcoma was significantly higher than the concentration in each of the other groups. A plasma cTnl concentration > 0.25 ng/mL could be used to identify cardiac involvement in dogs with hemangiosarcoma at any site (sensitivity, 78%; specificity, 71 %). A plasma cTnl concentration > 0.25 ng/mL could be used to identify cardiac hemangiosarcoma in dogs with pericardia effusion (sensitivity, 81%; specificity, 100%). The median plasma cTnl concentration was higher in dogs with cardiac hemangiosarcoma, compared with the median concentration in dogs with hemangiosarcoma at other sites, dogs with other neoplasms, and dogs with pericardial effusion not caused by hemangiosarcoma. The plasma cTnl concentration may be used to identify cardiac involvement in dogs with hemangiosarcoma and to identify cardiac hemangiosarcoma in dogs with pericardial effusion.

Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient.

PubMed

Mercado, Pablo; Maizel, Julien; Beyls, Christophe; Titeca-Beauport, Dimitri; Joris, Magalie; Kontar, Loay; Riviere, Antoine; Bonef, Olivier; Soupison, Thierry; Tribouilloy, Christophe; de Cagny, Bertrand; Slama, Michel

2017-06-09

Cardiac output (CO) monitoring is a valuable tool for the diagnosis and management of critically ill patients. In the critical care setting, few studies have evaluated the level of agreement between CO estimated by transthoracic echocardiography (CO-TTE) and that measured by the reference method, pulmonary artery catheter (CO-PAC). The objective of the present study was to evaluate the precision and accuracy of CO-TTE relative to CO-PAC and the ability of transthoracic echocardiography to track variations in CO, in critically ill mechanically ventilated patients. Thirty-eight mechanically ventilated patients fitted with a PAC were included in a prospective observational study performed in a 16-bed university hospital ICU. CO-PAC was measured via intermittent thermodilution. Simultaneously, a second investigator used standard-view TTE to estimate CO-TTE as the product of stroke volume and the heart rate obtained during the measurement of the subaortic velocity time integral. Sixty-four pairs of CO-PAC and CO-TTE measurements were compared. The two measurements were significantly correlated (r = 0.95; p < 0.0001). The median bias was 0.2 L/min, the limits of agreement (LOAs) were -1.3 and 1.8 L/min, and the percentage error was 25%. The precision was 8% for CO-PAC and 9% for CO-TTE. Twenty-six pairs of ΔCO measurements were compared. There was a significant correlation between ΔCO-PAC and ΔCO-TTE (r = 0.92; p < 0.0001). The median bias was -0.1 L/min and the LOAs were -1.3 and +1.2 L/min. With a 15% exclusion zone, the four-quadrant plot had a concordance rate of 94%. With a 0.5 L/min exclusion zone, the polar plot had a mean polar angle of 1.0° and a percentage error LOAs of -26.8 to 28.8°. The concordance rate was 100% between 30 and -30°. When using CO-TTE to detect an increase in ΔCO-PAC of more than 10%, the area under the receiving operating characteristic curve (95% CI) was 0.82 (0.62-0.94) (p < 0.001). A ΔCO-TTE of more than 8

Recent results on output feedback problems

NASA Technical Reports Server (NTRS)

Byrnes, C. I.

1980-01-01

Given a real linear system sigma = (A, B, C) with m inputs, p outputs and degree n, the problem of generic pole placement by output feedback is studied, which is to compute the constant C(m,p) such that the inequality C(m,p) not less than n is necessary and sufficient for generically positioning the poles of the generic linear system by constant output feedback. A constant C prime (m,p) is determined, which gives a sufficient condition for generic pole placement and which, to the best of the author's knowledge, is at least as good an estimate of C(m,p) as any in the literature. Some results on the construction of solutions in case mp = n are announced, based on the degree formula of Brockett and Byrnes and the Galois theory. In particular, a question raised by Anderson, Bose, and Jury, on the existence of a rational procedure for computing the feedback law from the desired characteristic polynomial is answered.

Living cardiac patch: the elixir for cardiac regeneration.

PubMed

Lakshmanan, Rajesh; Krishnan, Uma Maheswari; Sethuraman, Swaminathan

2012-12-01

A thorough understanding of the cellular and muscle fiber orientation in left ventricular cardiac tissue is of paramount importance for the generation of artificial cardiac patches to treat the ischemic myocardium. The major challenge faced during cardiac patch engineering is to choose a perfect combination of three entities; cells, scaffolds and signaling molecules comprising the tissue engineering triad for repair and regeneration. This review provides an overview of various scaffold materials, their mechanical properties and fabrication methods utilized in cardiac patch engineering. Stem cell therapies in clinical trials and the commercially available cardiac patch materials were summarized in an attempt to provide a recent perspective in the treatment of heart failure. Various tissue engineering strategies employed thus far to construct viable thick cardiac patches is schematically illustrated. Though many strategies have been proposed for fabrication of various cardiac scaffold materials, the stage and severity of the disease condition demands the incorporation of additional cues in a suitable scaffold material. The scaffold may be nanofibrous patch, hydrogel or custom designed films. Integration of stem cells and biomolecular cues along with the scaffold may provide the right microenvironment for the repair of unhealthy left ventricular tissue as well as promote its regeneration.

Digoxin Induces Cardiac Hypertrophy Without Negative Effects on Cardiac Function and Physical Performance in Trained Normotensive Rats.

PubMed

Neves, Claodete Hasselstrom; Tibana, Ramires Alsamir; Prestes, Jonato; Voltarelli, Fabricio Azevedo; Aguiar, Andreo Fernando; Ferreira Mota, Gustavo Augusto; de Sousa, Sergio Luiz Borges; Leopoldo, Andre Soares; Leopoldo, Ana Paula Lima; Mueller, Andre; Aguiar, Danilo Henrique; Navalta, James Wilfred; Sugizaki, Mario Mateus

2017-04-01

Cardiotonic drugs and exercise training promote cardiac inotropic effects, which may affect training-induced cardiac adaptations. This study investigated the effects of long-term administration of digoxin on heart structure and function, and physical performance of rats submitted to high-intensity interval training (HIIT). Male Wistar rats, 60 days old, were divided into control (C), digoxin (DIGO), trained (T), and trained with digoxin (TDIGO). Digoxin was administered by gavage (30 µg/kg/day) for 75 days. The HIIT program consisted of treadmill running 60 min/day (8 min at 80% of the maximum speed (MS) and 2 min at 20% of the MS), 5 days per week during 60 days. The main cardiac parameters were evaluated by echocardiograph and cardiomyocyte area was determined by histology. There were no group x time effects of digoxin, HIIT or interactions (digoxin and HIIT) on functional echocardiographic parameters (heart rate; ejection fraction) or in the maximum exercise test. There was a group x time interaction, as evidenced by observed cardiac hypertrophy in the TDIGO group evaluated by ratio of left ventricle weight to body weight (p<0.002) and cardiomyocyte area (p<0.000002). Long-term administration of digoxin promoted cardiac hypertrophy without affecting cardiac function and physical performance in rats submitted to HIIT. © Georg Thieme Verlag KG Stuttgart · New York.

Drosophila as a model to study cardiac aging

PubMed Central

Nishimura, Mayuko; Ocorr, Karen; Bodmer, Rolf; Cartry, Jérôme

2010-01-01

With age, cardiac performance declines progressively and the risk of heart disease, a primary cause of mortality, rises dramatically. As the elderly population continues to increase, it is critical to gain a better understanding of the genetic influences and modulatory factors that impact cardiac aging. In an attempt to determine the relevance and utility of the Drosophila heart in unraveling the genetic mechanisms underlying cardiac aging, a variety of heart performance assays have recently been developed to quantify Drosophila heart performance that permit the use of the fruit fly to investigate the heart’s decline with age. As for the human heart, Drosophila heart function also deteriorates with age. Notably, with progressive age the incidence of cardiac arrhythmias, myofibrillar disorganization and susceptibility to heart dysfunction and failure all increase significantly. We review here the evidence for an involvement of the insulin-TOR pathway, the KATP channel subunit dSur, the KCNQ potassium channel, as well as Dystrophin and Myosin in fly cardiac aging, and discuss the utility of the Drosophila heart model for cardiac aging studies. PMID:21130861

Pharmacological targeting of CDK9 in cardiac hypertrophy.

PubMed

Krystof, Vladimír; Chamrád, Ivo; Jorda, Radek; Kohoutek, Jirí

2010-07-01

Cardiac hypertrophy allows the heart to adapt to workload, but persistent or unphysiological stimulus can result in pump failure. Cardiac hypertrophy is characterized by an increase in the size of differentiated cardiac myocytes. At the molecular level, growth of cells is linked to intensive transcription and translation. Several cyclin-dependent kinases (CDKs) have been identified as principal regulators of transcription, and among these CDK9 is directly associated with cardiac hypertrophy. CDK9 phosphorylates the C-terminal domain of RNA polymerase II and thus stimulates the elongation phase of transcription. Chronic activation of CDK9 causes not only cardiac myocyte enlargement but also confers predisposition to heart failure. Due to the long interest of molecular oncologists and medicinal chemists in CDKs as potential targets of anticancer drugs, a portfolio of small-molecule inhibitors of CDK9 is available. Recent determination of CDK9's crystal structure now allows the development of selective inhibitors and their further optimization in terms of biochemical potency and selectivity. CDK9 may therefore constitute a novel target for drugs against cardiac hypertrophy.

Cardiac output in idiopathic normal pressure hydrocephalus: association with arterial blood pressure and intracranial pressure wave amplitudes and outcome of shunt surgery

PubMed Central

2011-01-01

Background In patients with idiopathic normal pressure hydrocephalus (iNPH) responding to shunt surgery, we have consistently found elevated intracranial pressure (ICP) wave amplitudes during diagnostic ICP monitoring prior to surgery. It remains unknown why ICP wave amplitudes are increased in these patients. Since iNPH is accompanied by a high incidence of vascular co-morbidity, a possible explanation is that there is reduced vascular compliance accompanied by elevated arterial blood pressure (ABP) wave amplitudes and even altered cardiac output (CO). To investigate this possibility, the present study was undertaken to continuously monitor CO to determine if it is correlated to ABP and ICP wave amplitudes and the outcome of shunting in iNPH patients. It was specifically addressed whether the increased ICP wave amplitudes seen in iNPH shunt responders were accompanied by elevated CO and/or ABP wave amplitude levels. Methods Prospective iNPH patients (29) were clinically graded using an NPH grading scale. Continuous overnight minimally-invasive monitoring of CO and ABP was done simultaneously with ICP monitoring; the CO, ABP, and ICP parameters were parsed into 6-second time windows. Patients were assessed for shunt surgery on clinical grade, Evan's index, and ICP wave amplitude. Follow-up clinical grading was performed 12 months after surgery. Results ICP wave amplitudes but not CO or ABP wave amplitude, showed good correlation with the response to shunt treatment. The patients with high ICP wave amplitude did not have accompanying high levels of CO or ABP wave amplitude. Correlation analysis between CO and ICP wave amplitudes in individual patients showed different profiles [significantly positive in 10 (35%) and significantly negative in 16 (55%) of 29 recordings]. This depended on whether there was also a correlation between ABP and ICP wave amplitudes and on the average level of ICP wave amplitude. Conclusions These results gave no evidence that the increased

Risk model for deaths and renal replacement therapy dependence in patients with acute kidney injury after cardiac surgery.

PubMed

Sun, Shiren; Ma, Feng; Li, Qiaoneng; Bai, Ming; Li, Yangping; Yu, Yan; Huang, Chen; Wang, Hanmin; Ning, Xiaoxuan

2017-10-01

Acute kidney injury (AKI) is a serious complication after cardiac surgery and is associated with increased in-hospital deaths. Renal replacement therapy (RRT) is becoming a routine strategy for severe AKI. Our goal was to evaluate the risk factors for death and RRT dependence in patients with AKI after cardiac surgery. We included 190 eligible adult patients who had AKI following cardiac surgery and who required RRT at our centre from November 2010 to March 2015. We collected preoperative, intraoperative, postoperative and RRT data for all patients. In this cohort, 87 patients had successful RRT in the hospital, whereas 103 patients had RRT that failed (70 deaths and 33 cases of RRT dependence). The multivariable logistic analysis identified old age [odds ratio (OR): 1.042, 95% confidence interval (CI): 1.012-1.074; P = 0.011], serum uric acid (OR: 1.015, 95% CI: 1.003-1.031; P = 0.024), intraoperative concentrated red blood cell transfusions (OR: 1.144, 95% CI: 1.006-1.312; P = 0.041), postoperative low cardiac output syndrome (OR: 3.107, 95% CI: 1.179-8.190; P = 0.022) and multiple organ failure (OR: 5.786, 95% CI: 2.115-15.832; P = 0.001) as factors associated with a higher risk for RRT failure. The prediction model (-4.3 + 0.002 × preuric acid + 0.10 × concentrated red blood cells + 0.04 × age + 1.12 × [low cardiac output syndrome = 1] + 1.67 × [multiple organ failure = 1]) based on the multivariate analysis had statistically significant different incriminatory power with an area under the curve of 0.786. The prediction model may serve as a simple, accurate tool for predicting in-hospital RRT failure for patients with AKI following cardiac surgery. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

The Safety of Cardiac and Thoracic Magnetic Resonance Imaging in Patients with Cardiac Implantable Electronic Devices.

PubMed

Dandamudi, Sanjay; Collins, Jeremy D; Carr, James C; Mongkolwat, Pat; Rahsepar, Amir A; Tomson, Todd T; Verma, Nishant; Arora, Rishi; Chicos, Alex B; Kim, Susan S; Lin, Albert C; Passman, Rod S; Knight, Bradley P

2016-12-01

Studies reporting the safety of magnetic resonance imaging (MRI) in patients with a cardiac implantable electronic device (CIED) have mostly excluded examinations with the device in the magnet isocenter. The purpose of this study was to describe the safety of cardiac and thoracic spine MRI in patients with a CIED. The medical records of patients with a CIED who underwent a cardiac or thoracic spine MRI between January 2011 and December 2014 were reviewed. Devices were interrogated before and after imaging with reprogramming to asynchronous pacing in pacemaker-dependent patients. The clinical interpretability of the MRI and peak and average specific absorption rates (SARs, W/kg) achieved were determined. Fifty-eight patients underwent 51 cardiac and 11 thoracic spine MRI exams. Twenty-nine patients had a pacemaker and 29 had an implantable cardioverter defibrillator. Seventeen percent (n = 10) were pacemaker dependent. Fifty-one patients (89%) had non-MRI-conditional devices. There were no clinically significant changes in atrial and ventricular sensing, impedance, and threshold measurements. There were no episodes of device mode changes, arrhythmias, therapies delivered, electrical reset, or battery depletion. One study was prematurely discontinued due to a patient complaint of chest pain of which the etiology was not determined. Across all examinations, the average peak SAR was 2.0 ± 0.85 W/kg with an average SAR of 0.35 ± 0.37 W/kg. Artifact significantly limiting the clinical interpretation of the study was present in 33% of cardiac MRI studies. When a comprehensive CIED magnetic resonance safety protocol is followed, the risk of performing 1.5-T magnetic resonance studies with the device in the magnet isocenter, including in patients who are pacemaker dependent, is low. Copyright © 2016. Published by Elsevier Inc.

Hemodynamic effects of aerosol propellants. I. Cardiac depression in the dog.

PubMed

Simaan, J A; Aviado, D M

1975-11-01

The inhalation of fluorocarbons caused a depression of myocardial contractility, aortic hypotension, a decrease in cardiac output and an increase in pulmonary vascular resistance. The minimal concentrations that elicited these changes are as follows: 1% trichlorofluoromethane (FC11); 2.5% dichlorotetrafluoroethane (FC114); and 10% dichlorodifluoromethane (FC12). Inhalation of 20% octafluorocyclobutane (FC318) and difluoroethane (FC152a) did not influence these hemodynamic parameters. As in previous comparisons, the most widely used aerosol propellants are potentially cardiotoxic in the anesthetized dog.

Novel approaches to determine contractile function of the isolated adult zebrafish ventricular cardiac myocyte.

PubMed

Dvornikov, Alexey V; Dewan, Sukriti; Alekhina, Olga V; Pickett, F Bryan; de Tombe, Pieter P

2014-05-01

The zebrafish (Danio rerio) has been used extensively in cardiovascular biology, but mainly in the study of heart development. The relative ease of its genetic manipulation may indicate the suitability of this species as a cost-effective model system for the study of cardiac contractile biology. However, whether the zebrafish heart is an appropriate model system for investigations pertaining to mammalian cardiac contractile structure-function relationships remains to be resolved. Myocytes were isolated from adult zebrafish hearts by enzymatic digestion, attached to carbon rods, and twitch force and intracellular Ca(2+) were measured. We observed the modulation of twitch force, but not of intracellular Ca(2+), by both extracellular [Ca(2+)] and sarcomere length. In permeabilized cells/myofibrils, we found robust myofilament length-dependent activation. Moreover, modulation of myofilament activation-relaxation and force redevelopment kinetics by varied Ca(2+) activation levels resembled that found previously in mammalian myofilaments. We conclude that the zebrafish is a valid model system for the study of cardiac contractile structure-function relationships.

Initial Efficacy of a Cardiac Rehabilitation Transition Program: Cardiac TRUST

PubMed Central

Zullo, Melissa; Boxer, Rebecca; Moore, Shirley M.

2012-01-01

Patients recovering from cardiac events are increasingly using postacute care, such as home health care and skilled nursing facility services. The purpose of this pilot study was to test the initial efficacy, feasibility, and safety of a specially designed postacute care transitional rehabilitation intervention for cardiac patients. Cardiac Transitional Rehabilitation Using Self- Management Techniques (Cardiac TRUST) is a family-focused intervention that includes progressive low-intensity walking and education in self-management skills to facilitate recovery following a cardiac event. Using a randomized two-group design, exercise self-efficacy, steps walked, and participation in an outpatient cardiac rehabilitation program were compared in a sample of 38 older adults; 17 who received the Cardiac TRUST program and 21 who received usual care only. At discharge from postacute care, the intervention group had a trend for higher levels of self-efficacy for exercise outcomes (X=39.1, SD=7.4) than the usual care group (X=34.5; SD=7.0) (t-test 1.9, p=.06). During the 6 weeks following discharge, compared with the usual care group, the intervention group had more attendance in out-patient cardiac rehabilitation (33% compared to 11.8%, F=7.1, p=.03) and a trend toward more steps walked during the first week (X=1,307, SD=652 compared to X=782, SD=544, t-test 1.8, p=.07). The feasibility of the intervention was better for the home health participants than for those in the skilled nursing facility and there were no safety concerns. The provision of cardiac-focused rehabilitation during postacute care has the potential to bridge the gap in transitional services from hospitalization to outpatient cardiac rehabilitation for these patients at high risk for future cardiac events. Further evidence of the efficacy of Cardiac TRUST is warranted. PMID:22084960

Increased cardiac output, not pulmonary artery systolic pressure, increases intrapulmonary shunt in healthy humans breathing room air and 40% O2

PubMed Central

Elliott, Jonathan E; Duke, Joseph W; Hawn, Jerold A; Halliwill, John R; Lovering, Andrew T

2014-01-01

Blood flow through intrapulmonary arteriovenous anastomoses (IPAVAs) has been demonstrated to increase in healthy humans during a variety of conditions; however, whether or not this blood flow represents a source of venous admixture (/) that impairs pulmonary gas exchange efficiency (i.e. increases the alveolar-to-arterial difference (A–aDO2)) remains controversial and unknown. We hypothesized that blood flow through IPAVAs does provide a source of /. To test this, blood flow through IPAVAs was increased in healthy humans at rest breathing room air and 40% O2: (1) during intravenous adrenaline (epinephrine) infusion at 320 ng kg−1 min−1 (320 ADR), and (2) with vagal blockade (2 mg atropine), before and during intravenous adrenaline infusion at 80 ng kg−1 min−1 (ATR + 80 ADR). When breathing room air the A–aDO2 increased by 6 ± 2 mmHg during 320 ADR and by 5 ± 2 mmHg during ATR + 80 ADR, and the change in calculated / was +2% in both conditions. When breathing 40% O2, which minimizes contributions from diffusion limitation and alveolar ventilation-to-perfusion inequality, the A–aDO2 increased by 12 ± 7 mmHg during 320 ADR, and by 9 ± 6 mmHg during ATR + 80 ADR, and the change in calculated / was +2% in both conditions. During 320 ADR cardiac output () and pulmonary artery systolic pressure (PASP) were significantly increased; however, during ATR + 80 ADR only was significantly increased, yet blood flow through IPAVAs as detected with saline contrast echocardiography was not different between conditions. Accordingly, we suggest that blood flow through IPAVAs provides a source of intrapulmonary shunt, and is mediated primarily by increases in rather than PASP. PMID:25085889

Biomechanics of Cardiac Function

PubMed Central

Voorhees, Andrew P.; Han, Hai-Chao

2015-01-01

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

The effect of garden designs on mood and heart output in older adults residing in an assisted living facility.

PubMed

Goto, Seiko; Park, Bum-Jin; Tsunetsugu, Yuko; Herrup, Karl; Miyazaki, Yoshifumi

2013-01-01

The objective of this study is to trace short-term changes in mood and heart function in elderly individuals in response to exposure to different landscaped spaces. Nineteen elderly but cognitively intact residents of an assisted living facility participated in the study. They were exposed to three landscaped spaces: a Japanese style garden, an herb garden, and a simple landscaped area planted with a single tree. To assess the effect of different landscaped spaces on older adults, individuals were monitored for mood and cardiac function in response to short exposures to spaces. Mood state was assessed using Profile of Mood States (POMS) before and after viewing the spaces. Cardiac output was assessed using a portable electrocardiograph monitor before and during the viewing. We found that the structured gardens evoked greater responses in all outcome measures. Scores on the POMS improved after observation of the two organized gardens compared to responses to the simple landscaped space with a single tree. During the observation period, heart rate was significantly lower in the Japanese garden than in the other environments, and sympathetic function was significantly lower as well. We conclude that exposure to organized gardens can affect both the mood and cardiac physiology of elderly individuals. Our data further suggest that these effects can differ depending on the types of landscape to which an individual is exposed. Elderly, Japanese garden, herb garden, heart rate, mood, healing environmentPreferred Citation: Goto, S., Park, B-J., Tsunetsugu, Y., Herrup, K., & Miyazaki, Y. (2013). The effect of garden designs on mood and heart output in older adults residing in an assisted living facility. Health Environments Research & Design Journal 6(2), pp 27-42.

Validation of On-Orbit Methodology for the Assessment of Cardiac Function and Changes in the Circulating Volume Using Ultrasound and Braslet-M Occlusion Cuffs

NASA Technical Reports Server (NTRS)

Hamilton, Douglas; Sargsyan, Ashot E.; Ebert, Douglas; Duncan, Michael; Bogomolov, Valery V.; Alferova, Irina V.; Matveev, Vladimir P.; Dulchavsky, Scott A.

2010-01-01

Volume). Conclusions: This Study: 1) Addressed specific aspects of operational space medicine and space physiology, including assessment of circulating volume disturbances 2) Expanded the applications of diagnostic ultrasound imaging and Doppler techniques in microgravity. 3) Used respiratory maneuvers against the background of acute circulating volume manipulations which appear to enhance our ability to noninvasively detect volume-dependency in a number of cardiac and vascular parameters. 4) Determined that Tei index is not clinically changed therefore contractility not altered in the face of reduced preload. 5) Determined that increased Femoral Vein Area indicating blood being sequestered in lower extremities correlates with reduced preload and cardiac output. 6) That Braslet may be the only feasible means of acutely treating high pressure pulmonary edema in reduced gravity environments.

Brain-Heart Interaction: Cardiac Complications After Stroke.

PubMed

Chen, Zhili; Venkat, Poornima; Seyfried, Don; Chopp, Michael; Yan, Tao; Chen, Jieli

2017-08-04

Neurocardiology is an emerging specialty that addresses the interaction between the brain and the heart, that is, the effects of cardiac injury on the brain and the effects of brain injury on the heart. This review article focuses on cardiac dysfunction in the setting of stroke such as ischemic stroke, brain hemorrhage, and subarachnoid hemorrhage. The majority of post-stroke deaths are attributed to neurological damage, and cardiovascular complications are the second leading cause of post-stroke mortality. Accumulating clinical and experimental evidence suggests a causal relationship between brain damage and heart dysfunction. Thus, it is important to determine whether cardiac dysfunction is triggered by stroke, is an unrelated complication, or is the underlying cause of stroke. Stroke-induced cardiac damage may lead to fatality or potentially lifelong cardiac problems (such as heart failure), or to mild and recoverable damage such as neurogenic stress cardiomyopathy and Takotsubo cardiomyopathy. The role of location and lateralization of brain lesions after stroke in brain-heart interaction; clinical biomarkers and manifestations of cardiac complications; and underlying mechanisms of brain-heart interaction after stroke, such as the hypothalamic-pituitary-adrenal axis; catecholamine surge; sympathetic and parasympathetic regulation; microvesicles; microRNAs; gut microbiome, immunoresponse, and systemic inflammation, are discussed. © 2017 American Heart Association, Inc.

Automated Identification of the Heart Wall Throughout the Entire Cardiac Cycle Using Optimal Cardiac Phase for Extracted Features

NASA Astrophysics Data System (ADS)

Takahashi, Hiroki; Hasegawa, Hideyuki; Kanai, Hiroshi

2011-07-01

In most methods for evaluation of cardiac function based on echocardiography, the heart wall is currently identified manually by an operator. However, this task is very time-consuming and suffers from inter- and intraobserver variability. The present paper proposes a method that uses multiple features of ultrasonic echo signals for automated identification of the heart wall region throughout an entire cardiac cycle. In addition, the optimal cardiac phase to select a frame of interest, i.e., the frame for the initiation of tracking, was determined. The heart wall region at the frame of interest in this cardiac phase was identified by the expectation-maximization (EM) algorithm, and heart wall regions in the following frames were identified by tracking each point classified in the initial frame as the heart wall region using the phased tracking method. The results for two subjects indicate the feasibility of the proposed method in the longitudinal axis view of the heart.

Ephedrine fails to accelerate the onset of neuromuscular block by vecuronium.

PubMed

Komatsu, Ryu; Nagata, Osamu; Ozaki, Makoto; Sessler, Daniel I

2003-08-01

The onset time of neuromuscular blocking drugs is partially determined by circulatory factors, including muscle blood flow and cardiac output. We thus tested the hypothesis that a bolus of ephedrine accelerates the onset of vecuronium neuromuscular block by increasing cardiac output. A prospective, randomized study was conducted in 53 patients scheduled for elective surgery. After the induction of anesthesia, the ulnar nerve was stimulated supramaximally every 10 s, and the evoked twitch response of the adductor pollicis was recorded with accelerometry. Patients were maintained under anesthesia with continuous infusion of propofol for 10 min and then randomly assigned to ephedrine 210 microg/kg (n = 27) or an equivalent volume of saline (n = 26). The test solution was given 1 min before the administration of 0.1 mg/kg of vecuronium. Cardiac output was monitored with impedance cardiography. Ephedrine, but not saline, increased cardiac index (17%; P = 0.003). Nonetheless, the onset of 90% neuromuscular block was virtually identical in the patients given ephedrine (183 +/- 41 s) and saline (181 +/- 47 s). There was no correlation between cardiac index and onset of the blockade. We conclude that the onset of the vecuronium-induced neuromuscular block is primarily determined by factors other than cardiac output. The combination of ephedrine and vecuronium thus cannot be substituted for rapid-acting nondepolarizing muscle relaxants. Ephedrine increased cardiac index but failed to speed onset of neuromuscular block with vecuronium. We conclude that ephedrine administration does not shorten the onset time of vecuronium.

Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

NASA Astrophysics Data System (ADS)

Wang, Chu

correction factors for the MOSFET organ dose measurements in the following studies. Minor angular dependence (< +/-20% at all angles tested, < +/-10% at clinically relevant angles in cardiac catheterization) was observed. Second, the cardiac dose for common fluoroscopic imaging techniques for pediatric patients in the two age groups was measured. Imaging technique settings with variations of individual key imaging parameters were tested to observe the quantitative effect of imaging optimization or lack thereof. Along with each measurement, the two standard system output indices, the Air Kerma (AK) and Dose-Area Product (DAP), were also recorded and compared to the measured cardiac and skin doses -- the lack of correlation between the indices and the organ doses shed light to the substantial limitation of the indices in representing patient radiation dose, at least within the scope of this dissertation. Third, the effective dose (ED) for Posterior-Anterior and Lateral fluoroscopic imaging techniques for pediatric patients in the two age groups was determined. In addition, the dosimetric effect of removing the anti-scatter grid was studied, for which a factor-of-two ED rate reduction was observed for the imaging techniques. The Clinical Component involved analytical research to develop a validated retrospective cardiac dose reconstruction formulation and to propose the new Optimization Index which evaluates the level of optimization of the clinician's imaging usage during a procedure; and small sample group of actual procedures were used to demonstrate applicability of these formulations. In its entirety, the research represents a first-of-its-kind comprehensive approach in radiation dosimetry for pediatric cardiac catheterization; and separately, it is also modular enough that each individual section can serve as study templates for small-scale dosimetric studies of similar purposes. The data collected and algorithmic formulations developed can be of use in areas of

Optimal Output Trajectory Redesign for Invertible Systems

NASA Technical Reports Server (NTRS)

Devasia, S.

1996-01-01

Given a desired output trajectory, inversion-based techniques find input-state trajectories required to exactly track the output. These inversion-based techniques have been successfully applied to the endpoint tracking control of multijoint flexible manipulators and to aircraft control. The specified output trajectory uniquely determines the required input and state trajectories that are found through inversion. These input-state trajectories exactly track the desired output; however, they might not meet acceptable performance requirements. For example, during slewing maneuvers of flexible structures, the structural deformations, which depend on the required state trajectories, may be unacceptably large. Further, the required inputs might cause actuator saturation during an exact tracking maneuver, for example, in the flight control of conventional takeoff and landing aircraft. In such situations, a compromise is desired between the tracking requirement and other goals such as reduction of internal vibrations and prevention of actuator saturation; the desired output trajectory needs to redesigned. Here, we pose the trajectory redesign problem as an optimization of a general quadratic cost function and solve it in the context of linear systems. The solution is obtained as an off-line prefilter of the desired output trajectory. An advantage of our technique is that the prefilter is independent of the particular trajectory. The prefilter can therefore be precomputed, which is a major advantage over other optimization approaches. Previous works have addressed the issue of preshaping inputs to minimize residual and in-maneuver vibrations for flexible structures; Since the command preshaping is computed off-line. Further minimization of optimal quadratic cost functions has also been previously use to preshape command inputs for disturbance rejection. All of these approaches are applicable when the inputs to the system are known a priori. Typically, outputs (not inputs

Relations of insulin resistance and glycemic abnormalities to cardiovascular magnetic resonance measures of cardiac structure and function: the Framingham Heart Study.

PubMed

Velagaleti, Raghava S; Gona, Philimon; Chuang, Michael L; Salton, Carol J; Fox, Caroline S; Blease, Susan J; Yeon, Susan B; Manning, Warren J; O'Donnell, Christopher J

2010-05-01

Data regarding the relationships of diabetes, insulin resistance, and subclinical hyperinsulinemia/hyperglycemia with cardiac structure and function are conflicting. We sought to apply volumetric cardiovascular magnetic resonance (CMR) in a free-living cohort to potentially clarify these associations. A total of 1603 Framingham Heart Study Offspring participants (age, 64+/-9 years; 55% women) underwent CMR to determine left ventricular mass (LVM), LVM to end-diastolic volume ratio (LVM/LVEDV), relative wall thickness (RWT), ejection fraction, cardiac output, and left atrial size. Data regarding insulin resistance (homeostasis model, HOMA-IR) and glycemia categories (normal, impaired insulinemia or glycemia, prediabetes, and diabetes) were determined. In a subgroup (253 men, 290 women) that underwent oral glucose tolerance testing, we related 2-hour insulin and glucose with CMR measures. In both men and women, all age-adjusted CMR measures increased across HOMA-IR quartiles, but multivariable-adjusted trends were significant only for LVM/ht(2.7) and LVM/LVEDV. LVM/LVEDV and RWT were higher in participants with prediabetes and diabetes (in both sexes) in age-adjusted models, but these associations remained significant after multivariable adjustment only in men. LVM/LVEDV was significantly associated with 2-hour insulin in men only, and RWT was significantly associated with 2-hour glucose in women only. In multivariable stepwise selection analyses, the inclusion of body mass index led to a loss in statistical significance. Although insulin and glucose indices are associated with abnormalities in cardiac structure, insulin resistance and worsening glycemia are consistently and independently associated with LVM/LVEDV. These data implicate hyperglycemia and insulin resistance in concentric LV remodeling.

Prevalence, implication, and determinants of worsening renal function after surgery for congenital heart disease.

PubMed

Saiki, Hirofumi; Kuwata, Seiko; Kurishima, Clara; Iwamoto, Yoichi; Ishido, Hirotaka; Masutani, Satoshi; Senzaki, Hideaki

2016-08-01

Accumulating data in adults indicate the prognostic importance of worsening renal function (WRF) during treatment of acute heart failure. Venous congestion appears to play a dominant role in WRF; however, data regarding WRF in children with congenital heart disease (CHD) are limited. The present study was conducted to elucidate the prevalence and characteristics of WRF after surgery for CHD in children. We also tested our hypothesis that, similar to adult heart failure, venous congestion is an important determinant of WRF independent of cardiac output in this population. Fifty-five consecutive pediatric patients who underwent cardiovascular surgery for CHD were studied (median age 0.7 years; range 3 days to 17 years). The degree of WRF was assessed by the difference between the maximum levels of postoperative serum creatinine (Cr) and preoperative serum Cr. There was a high prevalence of WRF in the present cohort: an increase in Cr level was observed in 47 patients (85 %) and a Cr increase ≥0.3 mg/dL was seen in 23 (42 %). Importantly, WRF was significantly associated with a worse clinical outcome of a longer stay in the intensive care unit and hospital (both p < 0.05), even after controlling for age and operative factors. In addition, multivariate regression analysis revealed that central venous pressure, rather than cardiac output, was an independent determinant of WRF. Postoperative management to relieve venous congestion may help ameliorate or prevent WRF and thereby improve outcomes in patients with CHD.

MicroRNA-155 attenuates late sepsis-induced cardiac dysfunction through JNK and β-arrestin 2.

PubMed

Zhou, Yu; Song, Yan; Shaikh, Zahir; Li, Hui; Zhang, Haiju; Caudle, Yi; Zheng, Shouhua; Yan, Hui; Hu, Dan; Stuart, Charles; Yin, Deling

2017-07-18

Cardiac dysfunction is correlated with detrimental prognosis of sepsis and contributes to a high risk of mortality. After an initial hyperinflammatory reaction, most patients enter a protracted state of immunosuppression (late sepsis) that alters both innate and adaptive immunity. The changes of cardiac function in late sepsis are not yet known. MicroRNA-155 (miR-155) is previously found to play important roles in both regulations of immune activation and cardiac function. In this study, C57BL/6 mice were operated to develop into early and late sepsis phases, and miR-155 mimic was injected through the tail vein 48 h after cecal ligation and puncture (CLP). The effect of miR-155 on CLP-induced cardiac dysfunction was explored in late sepsis. We found that increased expression of miR-155 in the myocardium protected against cardiac dysfunction in late sepsis evidenced by attenuating sepsis-reduced cardiac output and enhancing left ventricular systolic function. We also observed that miR-155 markedly reduced the infiltration of macrophages and neutrophils into the myocardium and attenuated the inflammatory response via suppression of JNK signaling pathway. Moreover, overexpression of β-arrestin 2 (Arrb2) exacerbated the mice mortality and immunosuppression in late sepsis. Furthermore, transfection of miR-155 mimic reduced Arrb2 expression, and then restored immunocompetence and improved survival in late septic mice. We conclude that increased miR-155 expression through systemic administration of miR-155 mimic attenuates cardiac dysfunction and improves late sepsis survival by targeting JNK associated inflammatory signaling and Arrb2 mediated immunosuppression.

Implementation of a transfusion algorithm to reduce blood product utilization in pediatric cardiac surgery.

PubMed

Whitney, Gina; Daves, Suanne; Hughes, Alex; Watkins, Scott; Woods, Marcella; Kreger, Michael; Marincola, Paula; Chocron, Isaac; Donahue, Brian

2013-07-01

The goal of this project is to measure the impact of standardization of transfusion practice on blood product utilization and postoperative bleeding in pediatric cardiac surgery patients. Transfusion is common following cardiopulmonary bypass (CPB) in children and is associated with increased mortality, infection, and duration of mechanical ventilation. Transfusion in pediatric cardiac surgery is often based on clinical judgment rather than objective data. Although objective transfusion algorithms have demonstrated efficacy for reducing transfusion in adult cardiac surgery, such algorithms have not been applied in the pediatric setting. This quality improvement effort was designed to reduce blood product utilization in pediatric cardiac surgery using a blood product transfusion algorithm. We implemented an evidence-based transfusion protocol in January 2011 and monitored the impact of this algorithm on blood product utilization, chest tube output during the first 12 h of intensive care unit (ICU) admission, and predischarge mortality. When compared with the 12 months preceding implementation, blood utilization per case in the operating room odds ratio (OR) for the 11 months following implementation decreased by 66% for red cells (P = 0.001) and 86% for cryoprecipitate (P < 0.001). Blood utilization during the first 12 h of ICU did not increase during this time and actually decreased 56% for plasma (P = 0.006) and 41% for red cells (P = 0.031), indicating that the decrease in OR transfusion did not shift the transfusion burden to the ICU. Postoperative bleeding, as measured by chest tube output in the first 12 ICU hours, did not increase following implementation of the algorithm. Monthly surgical volume did not change significantly following implementation of the algorithm (P = 0.477). In a logistic regression model for predischarge mortality among the nontransplant patients, after accounting for surgical severity and duration of CPB, use of the transfusion

Nitrates for the prevention of cardiac morbidity and mortality in patients undergoing non-cardiac surgery.

PubMed

Zhao, Na; Xu, Jin; Singh, Balwinder; Yu, Xuerong; Wu, Taixiang; Huang, Yuguang

2016-08-04

resolved differences by discussion and, when necessary, sought help and suggestions from a third review author. We used a random-effects model for data analysis. We included 27 randomized controlled trials (RCTs) (8244 participants analysed). Investigators reported 12 different comparisons of three different nitrates (nitroglycerin, isosorbide dinitrate and nicorandil) versus no treatment, placebo or other pharmacological interventions. All participants were older than 15 years of age. More than half of the trials used general anaesthesia. Surgical procedures in most trials were at low to moderate risk for perioperative cardiac complications. Only two comparisons including three studies reported the primary outcome - all-cause mortality up to 30 days post operation. Researchers reported other morbidity outcomes and adverse events in a variable and heterogeneous way, resulting in limited available data for inclusion in the meta-analysis. We determined that the overall methodological quality of included studies was fair to low, in accordance with risk of bias in most domains.In summary, we found no difference in the primary outcome - all-cause mortality up to 30 days post operation - when nitroglycerin was compared with no treatment (one study, 60 participants, 0/30 vs 1/30; (risk ratio (RR) 0.33, 95% confidence interval (CI) 0.01 to 7.87, very low-quality evidence based on GRADE criteria) or with placebo (two studies, 89 participants, 1/45 vs 0/44; RR 2.81, 95% CI 0.12 to 63.83, very low-quality evidence). Regarding our secondary outcomes, we noted no statistically significant differences in angina pectoris, acute myocardial infarction, acute heart failure, cardiac arrhythmia or cardiac arrest in any comparisons. In comparisons versus nitroglycerin, although more events of cardiac ischaemia were observed in participants receiving no treatment or placebo, we found no statistically significant differences in any comparisons, except the comparison of nicorandil versus placebo

Cardiac myofilaments: mechanics and regulation

NASA Technical Reports Server (NTRS)

de Tombe, Pieter P.; Bers, D. M. (Principal Investigator)

2003-01-01

The mechanical properties of the cardiac myofilament are an important determinant of pump function of the heart. This report is focused on the regulation of myofilament function in cardiac muscle. Calcium ions form the trigger that induces activation of the thin filament which, in turn, allows for cross-bridge formation, ATP hydrolysis, and force development. The structure and protein-protein interactions of the cardiac sarcomere that are responsible for these processes will be reviewed. The molecular mechanism that underlies myofilament activation is incompletely understood. Recent experimental approaches have been employed to unravel the mechanism and regulation of myofilament mechanics and energetics by activator calcium and sarcomere length, as well as contractile protein phosphorylation mediated by protein kinase A. Central to these studies is the question whether such factors impact on muscle function simply by altering thin filament activation state, or whether modulation of cross-bridge cycling also plays a part in the responses of muscle to these stimuli.

Fropofol decreases force development in cardiac muscle.

PubMed

Ren, Xianfeng; Schmidt, William; Huang, Yiyuan; Lu, Haisong; Liu, Wenjie; Bu, Weiming; Eckenhoff, Roderic; Cammarato, Anthony; Gao, Wei Dong

2018-03-09

Supranormal contractile properties are frequently associated with cardiac diseases. Anesthetic agents, including propofol, can depress myocardial contraction. We tested the hypothesis that fropofol, a propofol derivative, reduces force development in cardiac muscles via inhibition of cross-bridge cycling and may therefore have therapeutic potential. Force and intracellular Ca 2+ ([Ca 2+ ] i ) transients of rat trabecular muscles were determined. Myofilament ATPase, actin-activated myosin ATPase, and velocity of actin filaments propelled by myosin were also measured. Fropofol dose dependently decreased force without altering [Ca 2+ ] i in normal and pressure-induced hypertrophied-hypercontractile muscles. Similarly, fropofol depressed maximum Ca 2+ -activated force ( F max ) and increased the [Ca 2+ ] i required for 50% activation at steady-state (Ca 50 ) without affecting the Hill coefficient in both intact and skinned cardiac fibers. The drug also depressed cardiac myofibrillar and actin-activated myosin ATPase activity. In vitro actin sliding velocity was significantly reduced when fropofol was introduced during rigor binding of cross-bridges. The data suggest that the depressing effects of fropofol on cardiac contractility are likely to be related to direct targeting of actomyosin interactions. From a clinical standpoint, these findings are particularly significant, given that fropofol is a nonanesthetic small molecule that decreases myocardial contractility specifically and thus may be useful in the treatment of hypercontractile cardiac disorders.-Ren, X., Schmidt, W., Huang, Y., Lu, H., Liu, W., Bu, W., Eckenhoff, R., Cammarato, A., Gao, W. D. Fropofol decreases force development in cardiac muscle.

Determinants and prognostic implications of Cardiac Troponin T measured by a sensitive assay in Type 2 Diabetes Mellitus

PubMed Central

2010-01-01

Background The cardiac troponins are biomarkers used for diagnosis of myocardial injury. They are also powerful prognostic markers in many diseases and settings. Recently introduced high-sensitivity assays indicate that chronic cardiac troponin elevations are common in response to cardiovascular (CV) morbidity. Type 2 diabetes mellitus (T2DM) confers a high risk of CV disease, but little is known about chronic cardiac troponin elevations in diabetic subjects. Accordingly, we aimed to understand the prevalence, determinants, and prognostic implications of cardiac troponin T (cTnT) elevations measured with a high-sensitivity assay in patients with T2DM. Methods cTnT was measured in stored, frozen serum samples from 124 subjects enrolled in the Asker and Bærum Cardiovascular Diabetes trial at baseline and at 2-year follow-up, if availabe (96 samples available). Results were analyzed in relation to baseline variables, hospitalizations, and group assignment (multifactorial intensive versus conventional diabetes care for lowering CV risk). Results One-hundred thirteen (90 %) had detectable cTnT at baseline and of those, 22 (18 % of the total population) subjects had values above the 99th percentile for healthy controls (13.5 ng/L). Levels at baseline were associated with conventional CV risk factors (age, renal function, gender). There was a strong correlation between cTnT levels at the two time-points (r = 0.92, p > 0.001). Risk for hospitalizations during follow-up increased step-wise by quartiles of hscTnT measured at baseline (p = 0.058). Conclusions Elevations of cTnT above the 99th percentile measured by a highly sensitive assay were encountered frequently in a population of T2DM patients. cTnT levels appeared to be stable over time and associated with conventional CV risk factors. Although a clear trend was present, no statistically robust associations with adverse outcomes could be found. PMID:20843304

Cardiovascular Ultrasound of Neonatal Long Evans Rats Exposed Prenatally to Trichloroacetic Acid: Effects on Heart Rate, Ejection Fraction, and Cardiac Output

EPA Science Inventory

This abstract describes the use of a relatively new technology, cardiovascular ultrasound (echocardiography) for evaluating developmental toxicity affecting heart development. The abstract describes the effects of two known cardiac teratogens, trichloroacetic acid and dimethadio...

Toward microendoscopy-inspired cardiac optogenetics in vivo: technical overview and perspective

NASA Astrophysics Data System (ADS)

Klimas, Aleksandra; Entcheva, Emilia

2014-08-01

The ability to perform precise, spatially localized actuation and measurements of electrical activity in the heart is crucial in understanding cardiac electrophysiology and devising new therapeutic solutions for control of cardiac arrhythmias. Current cardiac imaging techniques (i.e. optical mapping) employ voltage- or calcium-sensitive fluorescent dyes to visualize the electrical signal propagation through cardiac syncytium in vitro or in situ with very high-spatiotemporal resolution. The extension of optogenetics into the cardiac field, where cardiac tissue is genetically altered to express light-sensitive ion channels allowing electrical activity to be elicited or suppressed in a precise cell-specific way, has opened the possibility for all-optical interrogation of cardiac electrophysiology. In vivo application of cardiac optogenetics faces multiple challenges and necessitates suitable optical systems employing fiber optics to actuate and sense electrical signals. In this technical perspective, we present a compendium of clinically relevant access routes to different parts of the cardiac electrical conduction system based on currently employed catheter imaging systems and determine the quantitative size constraints for endoscopic cardiac optogenetics. We discuss the relevant technical advancements in microendoscopy, cardiac imaging, and optogenetics and outline the strategies for combining them to create a portable, miniaturized fiber-based system for all-optical interrogation of cardiac electrophysiology in vivo.

Bridging the gap: Hybrid cardiac echo in the critically ill.

PubMed

Glaser, Jacob J; Cardarelli, Cassandra; Galvagno, Samuel; Scalea, Thomas M; Murthi, Sarah B

2016-11-01

Point-of-care ultrasound often includes cardiac ultrasound. It is commonly used to evaluate cardiac function in critically ill patients but lacks the specific quantitative anatomic assessment afforded by standard transthoracic echocardiography (TTE). We developed the Focused Rapid Echocardiographic Examination (FREE), a hybrid between a cardiac ultrasound and TTE that places an emphasis on cardiac function rather than anatomy. We hypothesized that data obtained from FREE correlate well with TTE while providing actionable information for clinical decision making. FREE examinations evaluating cardiac function (left ventricular ejection fraction), diastolic dysfunction (including early mitral Doppler flow [E] and early mitral tissue Doppler [E']), right ventricular function, cardiac output, preload (left ventricular internal dimension end diastole), stroke volume, stroke volume variation, inferior vena cava diameter, and inferior vena cava collapse were performed. Patients who underwent both a TTE and FREE on the same day were identified as the cohort, and quantitative measurements were compared. Correlation analyses were performed to assess levels of agreement. A total of 462 FREE examinations were performed, in which 69 patients had both a FREE and TTE. FREE ejection fraction was strongly correlated with TTE (r = 0.89, 95% confidence interval). Left ventricular outflow tract, left ventricular internal dimension end diastole, E, and lateral E' derived from FREE were also strongly correlated with TTE measurements (r = 0.83, r = 0.94, r = 0.77, and r = 0.88, respectively). In 82% of the patients, right ventricular function for FREE was the same as that reported for TTE; pericardial effusion was detected on both examinations in 94% of the cases. No significant valvular anatomy was missed with the FREE examination. Functionally rather than anatomically based hybrid ultrasound examinations, like the FREE, facilitate decision making for critically ill patients. The FREE

Electrocardiographic consequences of cardiac iron overload in thalassemia major

PubMed Central

Detterich, Jon; Noetzli, Leila; Dorey, Fred; Bar-Cohen, Yaniv; Harmatz, Paul; Coates, Thomas; Wood, John

2011-01-01

Background Iron cardiomyopathy is a leading cause of death in transfusion dependent thalassemia major (TM) patients and MRI (T2*) can recognize preclinical cardiac iron overload, but, is unavailable to many centers. Design and Methods We evaluated the ability of 12-lead electrocardiography to predict cardiac iron loading in TM. 12-lead electrocardiogram and cardiac T2* measurements were performed prospectively, with a detectable cardiac iron cutoff of T2*less than 20 ms. Patients with and without cardiac iron were compared using two-sample statistics and against population norms using age and gender-matched Z-scores. Results 45/78 patients had detectable cardiac iron. Patients having cardiac iron were older and more likely female but had comparable liver iron burdens and serum ferritin. Increased heart rate (HR) and prolonged corrected QT interval (QTc) were present, regardless of cardiac iron status. Repolarization abnormalities were the strongest predictors of cardiac iron, including QT/QTc prolongation, left shift of T-wave axis, and interpretation of ST/T-wave morphology. Recursive partitioning of the data for females using T-axis and HR and for males using QT, HR and T-axis produced algorithms with AUROC’s of 88.3 and 87.1 respectively. Conclusions Bradycardia and repolarization abnormalities on 12-lead electrocardiography were the most specific markers for cardiac iron in thalassemia major. Changes in these variables may be helpful to stratify cardiac risk when cardiac MRI is unavailable. However, diagnostic algorithms need to be vetted on larger and more diverse patient populations and longitudinal studies are necessary to determine reversibility of the observed abnormalities. PMID:22052662

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

PubMed

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

2018-03-01

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

Levosimendan in Patients with Left Ventricular Dysfunction Undergoing Cardiac Surgery.

PubMed

Mehta, Rajendra H; Leimberger, Jeffrey D; van Diepen, Sean; Meza, James; Wang, Alice; Jankowich, Rachael; Harrison, Robert W; Hay, Douglas; Fremes, Stephen; Duncan, Andra; Soltesz, Edward G; Luber, John; Park, Soon; Argenziano, Michael; Murphy, Edward; Marcel, Randy; Kalavrouziotis, Dimitri; Nagpal, Dave; Bozinovski, John; Toller, Wolfgang; Heringlake, Matthias; Goodman, Shaun G; Levy, Jerrold H; Harrington, Robert A; Anstrom, Kevin J; Alexander, John H

2017-05-25

Levosimendan is an inotropic agent that has been shown in small studies to prevent or treat the low cardiac output syndrome after cardiac surgery. In a multicenter, randomized, placebo-controlled, phase 3 trial, we evaluated the efficacy and safety of levosimendan in patients with a left ventricular ejection fraction of 35% or less who were undergoing cardiac surgery with the use of cardiopulmonary bypass. Patients were randomly assigned to receive either intravenous levosimendan (at a dose of 0.2 μg per kilogram of body weight per minute for 1 hour, followed by a dose of 0.1 μg per kilogram per minute for 23 hours) or placebo, with the infusion started before surgery. The two primary end points were a four-component composite of death through day 30, renal-replacement therapy through day 30, perioperative myocardial infarction through day 5, or use of a mechanical cardiac assist device through day 5; and a two-component composite of death through day 30 or use of a mechanical cardiac assist device through day 5. A total of 882 patients underwent randomization, 849 of whom received levosimendan or placebo and were included in the modified intention-to-treat population. The four-component primary end point occurred in 105 of 428 patients (24.5%) assigned to receive levosimendan and in 103 of 421 (24.5%) assigned to receive placebo (adjusted odds ratio, 1.00; 99% confidence interval [CI], 0.66 to 1.54; P=0.98). The two-component primary end point occurred in 56 patients (13.1%) assigned to receive levosimendan and in 48 (11.4%) assigned to receive placebo (adjusted odds ratio, 1.18; 96% CI, 0.76 to 1.82; P=0.45). The rate of adverse events did not differ significantly between the two groups. Prophylactic levosimendan did not result in a rate of the short-term composite end point of death, renal-replacement therapy, perioperative myocardial infarction, or use of a mechanical cardiac assist device that was lower than the rate with placebo among patients with a

Cardiac function and cognition in older community-dwelling cardiac patients.

PubMed

Eggermont, Laura H P; Aly, Mohamed F A; Vuijk, Pieter J; de Boer, Karin; Kamp, Otto; van Rossum, Albert C; Scherder, Erik J A

2017-11-01

Cognitive deficits have been reported in older cardiac patients. An underlying mechanism for these findings may be reduced cardiac function. The relationship between cardiac function as represented by different echocardiographic measures and different cognitive function domains in older cardiac patients remains unknown. An older (≥70 years) heterogeneous group of 117 community-dwelling cardiac patients under medical supervision by a cardiologist underwent thorough echocardiographic assessment including left ventricular ejection fraction, cardiac index, left atrial volume index, left ventricular mass index, left ventricular diastolic function, and valvular calcification. During a home visit, a neuropsychological assessment was performed within 7.1 ± 3.8 months after echocardiographic assessment; the neuropsychological assessment included three subtests of a word-learning test (encoding, recall, recognition) to examine one memory function domain and three executive function tests, including digit span backwards, Trail Making Test B minus A, and the Stroop colour-word test. Regression analyses showed no significant linear or quadratic associations between any of the echocardiographic functions and the cognitive function measures. None of the echocardiographic measures as representative of cardiac function was correlated with memory or executive function in this group of community-dwelling older cardiac patients. These findings contrast with those of previous studies. © 2017 Japanese Psychogeriatric Society.

Bench-to-bedside review: the importance of the precision of the reference technique in method comparison studies--with specific reference to the measurement of cardiac output.

PubMed

Cecconi, Maurizio; Rhodes, Andrew; Poloniecki, Jan; Della Rocca, Giorgio; Grounds, R Michael

2009-01-01

Bland-Altman analysis is used for assessing agreement between two measurements of the same clinical variable. In the field of cardiac output monitoring, its results, in terms of bias and limits of agreement, are often difficult to interpret, leading clinicians to use a cutoff of 30% in the percentage error in order to decide whether a new technique may be considered a good alternative. This percentage error of +/- 30% arises from the assumption that the commonly used reference technique, intermittent thermodilution, has a precision of +/- 20% or less. The combination of two precisions of +/- 20% equates to a total error of +/- 28.3%, which is commonly rounded up to +/- 30%. Thus, finding a percentage error of less than +/- 30% should equate to the new tested technique having an error similar to the reference, which therefore should be acceptable. In a worked example in this paper, we discuss the limitations of this approach, in particular in regard to the situation in which the reference technique may be either more or less precise than would normally be expected. This can lead to inappropriate conclusions being drawn from data acquired in validation studies of new monitoring technologies. We conclude that it is not acceptable to present comparison studies quoting percentage error as an acceptability criteria without reporting the precision of the reference technique.

Output factor determination based on Monte Carlo simulation for small cone field in 10-MV photon beam.

PubMed

Fukata, Kyohei; Sugimoto, Satoru; Kurokawa, Chie; Saito, Akito; Inoue, Tatsuya; Sasai, Keisuke

2018-06-01

The difficulty of measuring output factor (OPF) in a small field has been frequently discussed in recent publications. This study is aimed to determine the OPF in a small field using 10-MV photon beam and stereotactic conical collimator (cone). The OPF was measured by two diode detectors (SFD, EDGE detector) and one micro-ion chamber (PinPoint 3D chamber) in a water phantom. A Monte Carlo simulation using simplified detector model was performed to obtain the correction factor for the detector measurements. About 12% OPF difference was observed in the measurement at the smallest field (7.5 mm diameter) for EDGE detector and PinPoint 3D chamber. By applying the Monte Carlo-based correction factor to the measurement, the maximum discrepancy among the three detectors was reduced to within 3%. The results indicate that determination of OPF in a small field should be carefully performed. Especially, detector choice and appropriate correction factor application are very important in this regard.

Characterizing cardiac arrest in children undergoing cardiac surgery: A single-center study.

PubMed

Gupta, Punkaj; Wilcox, Andrew; Noel, Tommy R; Gossett, Jeffrey M; Rockett, Stephanie R; Eble, Brian K; Rettiganti, Mallikarjuna

2017-02-01

To characterize cardiac arrest in children undergoing cardiac surgery using single-center data from the Society of Thoracic Surgeons and Pediatric Advanced Life Support Utstein-Style Guidelines. Patients aged 18 years or less having a cardiac arrest for 1 minute or more during the same hospital stay as heart operation qualified for inclusion (2002-2014). Patients having a cardiac arrest both before or after heart operation were included. Heart operations were classified on the basis of the first cardiovascular operation of each hospital admission (the index operation). The primary outcome was survival to hospital discharge. A total of 3437 children undergoing at least 1 heart operation were included. Overall rate of cardiac arrest among these patients was 4.5% (n = 154) with survival to hospital discharge of 84 patients (66.6%). Presurgery cardiac arrest was noted among 28 patients, with survival of 21 patients (75%). Among the 126 patients with postsurgery cardiac arrest, survival was noted among 84 patients (66.6%). Regardless of surgical case complexity, the median days between heart operation and cardiac arrest, duration of cardiac arrest, and survival after cardiac arrest were similar. The independent risk factors associated with improved chances of survival included shorter duration of cardiac arrest (odds ratio, 1.12; 95% confidence interval, 1.05-1.20; P = .01) and use of defibrillator (odds ratio, 4.51; 95% confidence interval, 1.08-18.87; P = .03). This single-center study demonstrates that characterizing cardiac arrest in children undergoing cardiac surgery using definitions from 2 societies helps to increase data granularity and understand the relationship between cardiac arrest and heart operation in a better way. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

From the bottom of the heart: Measuring liver iron concentration on cardiac MRI.

PubMed

Tan, Stephanie; Peng, Qi; Liszewski, Mark C; Taragin, Benjamin H

Patients with hemochromatosis require regular surveillance of liver and cardiac iron concentration with liver and cardiac MRI. However, cardiac MRI includes a part of the liver in the field of view. The purpose of this retrospective and prospective study is to determine if liver T2* measured on cardiac MRI may be used as a surrogate for T2* obtained on standard liver MRI. Liver iron concentrations were measured on cardiac and liver MRI in 21 patients. Although statistically significant, the difference may be clinically insignificant as the same patients merited chelation therapy when relying on either the cardiac or liver MRI. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardiopulmonary resuscitation duration and survival in out-of-hospital cardiac arrest patients.

PubMed

Adnet, Frederic; Triba, Mohamed N; Borron, Stephen W; Lapostolle, Frederic; Hubert, Hervé; Gueugniaud, Pierre-Yves; Escutnaire, Josephine; Guenin, Aurelien; Hoogvorst, Astrid; Marbeuf-Gueye, Carol; Reuter, Paul-Georges; Javaud, Nicolas; Vicaut, Eric; Chevret, Sylvie

2017-02-01

Relationship between cardiopulmonary arrest and resuscitation (CPR) durations and survival after out-of-hospital cardiac arrest (OHCA) remain unclear. Our primary aim was to determine the association between survival without neurologic sequelae and cardiac arrest intervals in the setting of witnessed OHCA. We analyzed 27,301 non-traumatic, witnessed OHCA patients in France included in the national registry from June 1, 2011 through December 1, 2015. We analyzed cardiac arrest intervals, designated as no-flow (NF; from collapse to start of CPR) and low-flow (LF; from start of CPR to cessation of resuscitation) in relation to 30-day survival without sequelae. We determined the influence of recognized prognostic factors (age, gender, initial rhythm, location of cardiac arrest) on this relation. For the entire cohort, the area delimited by a value of NF greater than 12min (95% confidence interval: 11-13min) and LF greater than 33min (95% confidence interval: 29-45min), yielded a probability of 30-day survival of less than 1%. These sets of values were greatly influenced by initial cardiac arrest rhythm, age, sex and location of cardiac arrest. Extended CPR duration (greater than 40min) in the setting of initial shockable cardiac rhythm is associated with greater than 1% survival with NF less than 18min. The NF interval was highly influential on the LF interval regardless of outcome, whether return of spontaneous circulation (p<0.001) or death (p<0.001). NF duration must be considered in determining CPR duration in OHCA patients. The knowledge of (NF, LF) curves as function of age, initial rhythm, location of cardiac arrest or gender may aid in decision-making vis-à-vis the termination of CPR or employment of advanced techniques. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Multiple-Input Multiple-Output (MIMO) Linear Systems Extreme Inputs/Outputs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smallwood, David O.

2007-01-01

A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the autospectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the autospectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input autospectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one willmore » result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.« less

Cardiac ion channels

PubMed Central

Priest, Birgit T; McDermott, Jeff S

2015-01-01

Ion channels are critical for all aspects of cardiac function, including rhythmicity and contractility. Consequently, ion channels are key targets for therapeutics aimed at cardiac pathophysiologies such as atrial fibrillation or angina. At the same time, off-target interactions of drugs with cardiac ion channels can be the cause of unwanted side effects. This manuscript aims to review the physiology and pharmacology of key cardiac ion channels. The intent is to highlight recent developments for therapeutic development, as well as elucidate potential mechanisms for drug-induced cardiac side effects, rather than present an in-depth review of each channel subtype. PMID:26556552

Cardiac registers: the adult cardiac surgery register.

PubMed

Bridgewater, Ben

2010-09-01

AIMS OF THE SCTS ADULT CARDIAC SURGERY DATABASE: To measure the quality of care of adult cardiac surgery in GB and Ireland and provide information for quality improvement and research. Feedback of structured data to hospitals, publication of named hospital and surgeon mortality data, publication of benchmarked activity and risk adjusted clinical outcomes through intermittent comprehensive database reports, annual screening of all hospital and individual surgeon risk adjusted mortality rates by the professional society. All NHS hospitals in England, Scotland and Wales with input from some private providers and hospitals in Ireland. 1994-ongoing. Consecutive patients, unconsented. Current number of records: 400000. Adult cardiac surgery operations excluding cardiac transplantation and ventricular assist devices. 129 fields covering demographic factors, pre-operative risk factors, operative details and post-operative in-hospital outcomes. Entry onto local software systems by direct key board entry or subsequent transcription from paper records, with subsequent electronic upload to the central cardiac audit database. Non-financial incentives at hospital level. Local validation processes exist in the hospitals. There is currently no external data validation process. All cause mortality is obtained through linkage with Office for National Statistics. No other linkages exist at present. Available for research and audit by application to the SCTS database committee at http://www.scts.org.

Change in end-tidal carbon dioxide outperforms other surrogates for change in cardiac output during fluid challenge.

PubMed

Lakhal, K; Nay, M A; Kamel, T; Lortat-Jacob, B; Ehrmann, S; Rozec, B; Boulain, T

2017-03-01

During fluid challenge, volume expansion (VE)-induced increase in cardiac output (Δ VE CO) is seldom measured. In patients with shock undergoing strictly controlled mechanical ventilation and receiving VE, we assessed minimally invasive surrogates for Δ VE CO (by transthoracic echocardiography): fluid-induced increases in end-tidal carbon dioxide (Δ VE E'CO2 ); pulse (Δ VE PP), systolic (Δ VE SBP), and mean systemic blood pressure (Δ VE MBP); and femoral artery Doppler flow (Δ VE FemFlow). In the absence of arrhythmia, fluid-induced decrease in heart rate (Δ VE HR) and in pulse pressure respiratory variation (Δ VE PPV) were also evaluated. Areas under the receiver operating characteristic curves (AUC ROC s) reflect the ability to identify a response to VE (Δ VE CO ≥15%). In 86 patients, Δ VE E'CO2 had an AUC ROC =0.82 [interquartile range 0.73-0.90], significantly higher than the AUC ROC for Δ VE PP, Δ VE SBP, Δ VE MBP, and Δ VE FemFlow (AUC ROC =0.61-0.65, all P  <0.05). A value of Δ VE E'CO2  >1 mm Hg (>0.13 kPa) had good positive (5.0 [2.6-9.8]) and fair negative (0.29 [0.2-0.5]) likelihood ratios. The 16 patients with arrhythmia had similar relationships between Δ VE E'CO2 and Δ VE CO to patients with regular rhythm ( r 2 =0.23 in both subgroups). In 60 patients with no arrhythmia, Δ VE E'CO2 (AUC ROC =0.84 [0.72-0.92]) outperformed Δ VE HR (AUC ROC =0.52 [0.39-0.66], P <0.05) and tended to outperform Δ VE PPV (AUC ROC =0.73 [0.60-0.84], P =0.21). In the 45 patients with no arrhythmia and receiving ventilation with tidal volume <8 ml kg -1 , Δ VE E'CO2 performed better than Δ VE PPV, with AUC ROC =0.86 [0.72-0.95] vs 0.66 [0.49-0.80], P =0.02. Δ VE E'CO2 outperformed Δ VE PP, Δ VE SBP, Δ VE MBP, Δ VE FemFlow, and Δ VE HR and, during protective ventilation, arrhythmia, or both, it also outperformed Δ VE PPV. A value of Δ VE E'CO2 >1 mm Hg (>0.13 kPa) indicated a likely response to VE. © The Author 2017

Urine output - decreased

MedlinePlus

... this page: //medlineplus.gov/ency/article/003147.htm Urine output - decreased To use the sharing features on this page, please enable JavaScript. Decreased urine output means that you produce less urine than ...

Determination of the optimum number of cardiac cycles to differentiate intra-pulmonary shunt and patent foramen ovale by saline contrast two- and three-dimensional echocardiography.

PubMed

Bhatia, Nirmanmoh; Abushora, Mohannad Y; Donneyong, Macarius M; Stoddard, Marcus F

2014-03-01

Patent foramen ovale (PFO) and intra-pulmonary shunt (IPS) are potential causes of stroke. The most optimum cardiac cycle cutoff for bubbles to appear in the left heart on saline contrast transthoracic echocardiography (TTE) as criteria to differentiate the 2 entities is unknown. Ninety-five adult patients had saline contrast transesophageal echocardiography (TEE), two-dimensional (2D) and 3DTTE. Sensitivity and specificity of each cardiac cycle as cutoff to differentiate a PFO and IPS were obtained. Transesophageal echocardiography showed IPS in 28 and PFO in 15 patients. If bubbles appeared in the left heart within the first 4 cardiac cycles (the 4th cardiac cycle rule) as compared to alternate cutoffs, a PFO was most accurately diagnosed by both 2D and 3DTTE. Bubbles appearing at or after the 5th cardiac cycle most accurately determined an IPS. 3D versus 2DTTE had a trend for a higher sensitivity (61% vs. 36%, P = 0.06), but similar specificity (94% vs. 91%) for IPS. Accuracy of 3DTTE was 84% and 2DTTE was 75% (P = 0.08) for IPS. For PFO, 2DTTE sensitivity (87%) and specificity (98%) did not differ (P = NS) from that of 3DTTE sensitivity (73%) and specificity (100%). This study demonstrates for the first time that the 4th cardiac cycle rule differentiates PFO and IPS most optimally by 2D and 3DTTE. 3DTTE appears to have higher sensitivity for diagnosing IPS. These data suggest that 3DTTE is preferable when IPS is to be diagnosed. Both methods are similar for diagnosing PFO. © 2013, Wiley Periodicals, Inc.

Oil Exposure Impairs In Situ Cardiac Function in Response to β-Adrenergic Stimulation in Cobia (Rachycentron canadum).