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PubMed2006

Postmortem pericardial natriuretic peptides as markers of cardiac function in medico-legal autopsies.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the blood are clinical markers for the diagnosis of cardiac failure. This study was a comprehensive analysis of the postmortem pericardial levels of the natriuretic peptides in serial medico-legal autopsy cases (n=263, within 72 h postmortem) to assess their validity in investigating cardiac function. There was no significant relationship of pericardial ANP or BNP levels with postmortem time or the age of the subjects. The ANP and BNP levels showed negative correlations with the pericardial cardiac troponin T level. The ANP level was significantly elevated in drowning cases. Pericardial BNP and the BNP/ANP ratio were significantly higher for chronic congestive heart disease. However, asphyxiation, sharp instrument injury, hyperthermia, and fatal MA poisoning cases showed lower levels for both markers. These observations suggest that elevations in the postmortem pericardial ANP and BNP may mainly depend on acute atrial overload and subacute or chronic cardiac failure, respectively, and may be reduced by advanced myocardial damage.

Adult↗
PubMed1995

Effects of short-term aminophylline administration on cardiac functional reserve in patients with syndrome X.

OBJECTIVES: This study sought to evaluate the effect of adenosine receptor blockade by aminophylline on cardiac functional reserve in patients with syndrome X. BACKGROUND: Aminophylline may have a potentially antiischemic effect through the inhibition of adenosine and, thus, the coronary steal phenomenon in patients with syndrome X. METHODS: A single-blind, placebo-controlled study of an intravenous infusion of aminophylline (6 mg/kg body weight over 15 min) or placebo (20 ml of saline solution over 15 min) was performed during continuous radionuclide monitoring of left ventricular ejection fraction in 12 patients performing supine bicycle ergometric exercise. RESULTS: Aminophylline increased exercise time (aminophylline 400 s vs. placebo 355 s, p < 0.01), decreased degree of ST segment depression (aminophylline 1.6 mm vs. placebo 2.4 mm, p < 0.01) and either abolished (seven patients) or diminished (five patients) chest pain during exercise. Aminophylline also increased left ventricular ejection fraction at rest (aminophylline 66.5% vs. placebo 62.3%, p < 0.05) but did not improve its deterioration at peak exercise (aminophylline 60.1% vs. placebo 56.6%, p = NS) or shorten the abnormally prolonged interval between the end of exercise and the overshoot (aminophylline 115 s vs. placebo 130 s, p = NS). CONCLUSIONS: Aminophylline infusion increases ischemic threshold and prolongs exercise duration in patients with syndrome X. It is hypothesized that aminophylline acts by inhibiting the coronary steal phenomenon through adenosine receptor blockade. It does not improve the deterioration in left ventricular function at peak exercise or the delayed response in ejection fraction in the recovery period, presumably because the beneficial effects of aminophylline that result from the redistribution of coronary blood flow are limited.

Aminophylline↗
PubMed2004

[Assessment of cardiac function by magnetic resonance and multislice spiral computed tomography].

Magnetic resonance imaging and multislice spiral computed tomography are ideal techniques for assessing cardiac function. The main objectives of this article are to describe the different aspects, global and regional systolic left ventricular function, diastolic left ventricular function and right ventricular function, and to introduce the agreed parameters for this evaluation.

Coronary Circulation↗
PubMed1989

[Relationship between left atrial diameter and cardiac function in myocardial infarction--assessment of left ventricular end-diastolic pressure by the left atrial index].

To study the assessment of cardiac function in acute myocardial infarction (AMI), we measured left atrial diameter, left ventricular end-diastolic pressure (LVEDP), pulmonary capillary wedge pressure (PCWP), ejection fraction (EF) in 20 patients with acute myocardial infarction. Left atrial diameter was measured using echocardiography and was expressed as left atrial index (LAI, mm/m2) dividing by body surface area. LAI in AMI was 21.3 +/- 2.7 mm/m2 and significantly larger than LAI in normal subject (19.9 +/- 2.0 mm/m2) (p less than 0.05), In AMI, LVEDP was 13.3 +/- 3.4 mmHg, PCWP was 9.0 +/- 2.8 mmHg and EF was 52.3 +/- 14.8%, Relationship (r value) between LAI and LVEDP (r = 0.70, p less than 0.001, y = 0.87 x-5.4 x; LAI, y; LVEDP) was greater than PCWP and LVEDP (r = 0.60, p less than 0.01). LVEDP calculated from LAI using this method was directly measured LVEDP directly measured +/- 2.4 mmHg. In 9 patients, LAI was larger than 20.9 mm/m2, in 8 patients of them LVEDP was higher than 13 mmHg. In 11 patients LAI was smaller than 20.9 mmHg, only in 2 of them LVEDP was lower than 13 mmHg. It concluded that sensitivity was 88.9%, specificity was 81.8%, accuracy was 85.0%. Relationship between LAI and PCWP (r = 0.30), LAI and EF (r = -0.36) were not significant. We can measure LAI repeatedly in AMI non-invasively, and predict LVEDP. Thus, the measurement of LAI is useful in treatment of AMI.

Adult↗
PubMed1978

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole dihydrochloride (DEPO) on cardiac functions and myocardial metabolism of the dog.

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole (DEPO) on cardiac functions and myocardial metabolism were examined using the heart in vivo and the isolated perfused heart of dogs. In the heart in vivo DEPO i.v. produced dose-dependent decreases in coronary perfusion pressure (PP), heart rate (HR), left ventricular pressure (LVP), dP/dt max of LVP and coronary vascular resistance (VR). DEPO i.c. dose-dependently increased left circumflex coronary flow (LCCF) and decreased PP, LVP and dP/dt max of LVP, but did not change HR. In the isolated perfused heart, DEPO induced a marked increase in coronary blood flow (CBF) and depressed HR and myocardial contractile force. Myocardial oxygen consumption and myocardial redox potential were not significantly changed. DEPO could not modify the effects of isoproterenol, adenosine and reactive hyperaemia on the heart. The results suggest that DEPO may have a coronary vasodilating action and some direct inhibitory actions on the heart.

Adenosine↗
PubMed1981

Hepatic sequelae of congestive cardiac failure. Evidence for a liver lesion in patients in whom cardiac function has been restored to normal.

In order to test the hypothesis that clinical and biochemical features of liver disease due to cardiac failure regress upon relief of cardiac decompensation, 38 patients with constrictive pericarditis were studied before and after pericardiectomy for periods ranging from 1 week to 25 years. All patients were judged to be free of clinical evidence of heart failure. Hepatomegaly was present in 10 of the 38 patients studied. Of the patients studied 1-25 years after operation, 96% had elevated serum levels of total and conjugated bilirubin. The percentage Bromsulphalein (BSP) retention at 45 minutes was abnormal in all 29 patients studied 1 year or more after surgery. There was no significant correlation between the level of bilirubin or the percentage BSP retained when these were compared with the pre-operative height of jugular venous pressure, degree of pulsus paradoxus, duration of symptoms or degree of hepatic congestion. Our study reveals that the liver lesion of cardiac failure persists for up to 25 years after restoration of normal cardiac function.

Adolescent↗
PubMed1990

Cardiac function and morphology of Hanford miniature swine and Yucatan miniature and micro swine.

The use of miniature swine in biomedical research is increasing; however, a comparison of cardiac function and morphology between strains has yet to be characterized. The purpose of this project was to examine comprehensive hemodynamics and cardiac morphology of three groups of ten normal, 4 months old, age-matched Yucatan miniature (MINI) pigs, Yucatan micropigs (MICRO) and Hanford (HAN) miniature pigs, 5 males and five females per group. Closed chest cardiac catheterization under equivalent conditions was performed followed by post mortem cardiac morphometry. Mean arterial pressure was significantly greater in the Hanford group when compared to both the minipig and micropig pigs (HAN: 89 +/- 4; MINI: 48 +/- 3; MICRO: 53 +/- 2 mmHg). Pulmonary vascular resistance was significantly different between the three groups (HAN: 9 +/- 1; MINI: 60 +/- 12; MICRO: 111 +/- 29 dyne x sec/cm x m2). The Hanford strain had a significantly smaller heart weight to body weight ratio than the other two groups (HAN: 4.6 +/- 1.0; MINI: 5.7 +/- 0.1; MICRO: 5.5 +/- 1.0). Variations in cardiovascular parameters occur among these strains and should be considered when constructing experimental designs.

Animals↗
PubMed1995

Enhancement of cardiac function by cyclocreatine in models of cardiopulmonary bypass.

This study tests the hypothesis that the administration of cyclocreatine prior to global ischemia enhances recovery of cardiac function during reperfusion. Two models were used. First, in a Langendorff-working heart model of normothermic cardioplegic arrest, rats (n = 6 per group) were injected intravenously with saline or cyclocreatine (600, 300, or 150 mg/kg). After 30 min or 2 h, hearts were excised and perfused in the Langendorff mode for 5 min and then in the working heart mode for 20 min. Normothermic arrest was induced by infusing warm St. Thomas solution once; then hearts were kept at 37 degrees C for 40 min. Following arrest, hearts were reperfused in the Langendorff mode for 15 min and then in the working mode for 30 min. Cyclocreatine consistently produced significantly better recovery of aortic flow and cardiac output compared to that of saline hearts. Second, in an intact canine model of cold cardioplegic arrest, adult mongrel dogs (n = 3 to 6 per group) underwent aortic cross-clamping for 1 h, followed by reperfusion on bypass for 45 min and off bypass for 4 h. Dogs were injected intravenously with saline or cyclocreatine (500 mg/kg) for 1 h before experiment. Post-bypass segmental contractility and cardiac output were significantly better in cyclocreatine hearts compared to that of controls. In a limited study, after a 3 h aortic cross-clamp time, cyclocreatine hearts achieved 91% baseline function while control hearts failed after 2 h. Results of this study suggest that cyclocreatine, without inotropic or chronotropic effect, protects the heart from global ischemic injury.

Animals↗
PubMed2000

Developmental changes of cardiac function and mass assessed with MRI in neonatal, juvenile, and adult mice.

Cardiovascular transgenic mouse models with an early phenotype or even premature death require noninvasive imaging methods that allow for accurate visualization of cardiac morphology and function. Thus the purpose of our study was to assess the feasibility of magnetic resonance imaging (MRI) to characterize cardiac function and mass in newborn, juvenile, and adult mice. Forty-five C57bl/6 mice from seven age groups (3 days to 4 mo after birth) were studied by MRI under isoflurane anesthesia. Electrocardiogram-gated cine MRI was performed with an in-plane resolution of (78-117 microm)(2). Temporal resolution per cine frame was 8.6 ms. MRI revealed cardiac anatomy in mice from all age groups with high temporal and spatial resolution. There was close correlation between MRI- and autopsy-determined left ventricular (LV) mass (r = 0.95, SE of estimate = 9.5 mg). The increase of LV mass (range 9.6-101.3 mg), cardiac output (range 1.1-14.3 ml/min), and stroke volume (range 3. 2-40.2 microl) with age could be quantified by MRI measurements. Ejection fraction and cardiac index did not change with aging. However, LV mass index decreased with increasing age (P < 0.01). High-resolution MRI allows for accurate in vivo assessment of cardiac function in neonatal, juvenile, and adult mice. This method should be useful when applied in transgenic mouse models.

Aging↗
PubMed1991

Effects of regression of left ventricular hypertrophy following atenolol or bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats.

The effects of regression of left ventricular hypertrophy following atenolol and bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats (SHR) were studied. Atenolol (50 mg/kg/day) and bunazosin (5 mg/kg/day) were administered to SHR from 19 to 26 weeks of age, whereas tap water was given to control SHR and normotensive Wistar-Kyoto rats (WKY). Both atenolol and bunazosin significantly decreased arterial blood pressure and significantly decelerated the increase in left ventricular weight in SHR. At the end of the long-term treatment, hearts were removed and perfused by the working heart technique for 15 min, and then global ischemia was induced for either 10 or 30 min. The ischemic heart was reperfused for 30 min. The pressure-rate product and the extent of recovery of the coronary flow after reperfusion following 30 min of ischemia in the bunazosin-treated SHR were significantly higher than those in the control SHR and the atenolol-treated SHR. The levels of adenosine triphosphate (ATP), creatine phosphate (CrP), and energy charge potential in the SHR heart reperfused after 30 min of ischemia were significantly lower than those in the reperfused WKY. Both atenolol and bunazosin improved the restoration of ATP and CrP in SHR after reperfusion following 30 min of ischemia. In conclusion, antihypertensive therapy with either atenolol or bunazosin was effective in preventing cardiac hypertrophy and ischemic damage caused by different mechanisms. Factors resulting from stimulation of the cardiac alpha 1 adrenoceptor may play an important role in the development of hypertensive cardiac hypertrophy, just as factors resulting from stimulation of the beta 1-adrenoceptor do.

Adenosine Diphosphate↗
PubMed1995

Effects of Levosimendan, a cardiotonic agent targeted to troponin C, on cardiac function and on phosphorylation and Ca2+ sensitivity of cardiac myofibrils and sarcoplasmic reticulum in guinea pig heart.

A new cardiotonic agent, (R)-[[4-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)-phenyl] hydrazono]propanedinitrile (Levosimendan), has been developed and screened for its ability to bind to cardiac troponin C. In perfused hearts, low concentrations of 0.03 or 0.1 mumol/L Levosimendan increased +dP/dt, but did not affect the speed of relaxation and produced only a slight increase in spontaneous heart rate in the hearts perfused with 0.1 mumol/L of the drug. In these same hearts, perfusion with 0.03 mumol/L Levosimendan did not alter the 32P incorporation into troponin I or C protein, whereas a slight but significant increase was noted for phospholamban, with no detectable change in tissue cAMP levels. Administration of 0.1 or 0.3 mumol/L Levosimendan significantly increased myocardial cAMP levels as well as the phosphorylation of phospholamban, troponin I, and C protein. Levosimendan (0.03 to 10 mumol/L) reversibly increased force generated by detergent-extracted fiber bundles over a range of submaximally activating free Ca2+ concentrations with no significant effect on maximum force or on Ca2+ binding to myofilament troponin C. There was no direct effect of Levosimendan on Ca2+ uptake by vesicles of sarcoplasmic reticulum (SR). In contrast, under conditions optimal for cAMP-dependent phosphorylation, Levosimendan slightly but significantly lowered the concentration of Ca2+, yielding half-maximal uptake rates by the SR vesicles. Our results indicate that at low concentrations Levosimendan acts preferably as a Ca2+ sensitizer, whereas at higher concentrations its action as a phosphodiesterase inhibitor contributes to the positive inotropic effect.

Analysis of Variance↗
PubMed2005

Thickening of the infarcted wall by collagen injection improves left ventricular function in rats: a novel approach to preserve cardiac function after myocardial infarction.

OBJECTIVES: We determined whether collagen implantation could thicken the infarcted left ventricular (LV) wall and improve LV function. BACKGROUND: We hypothesized that thickening the infarcted wall by using collagen might result in some benefits that are similar to what previously had been reported when the infarcted wall was thickened with cells. METHODS: Fischer rats with one-week-old myocardial infarcts were injected with collagen or saline (100 microl) into the scar (n = 12 each group). Six weeks later, LV angiograms, hemodynamics, and regional myocardial blood flow were assessed. The hearts were processed for measurements of postmortem LV volume and histology. RESULTS: Collagen injection significantly increased scar thickness (719 +/- 26 microm) compared with the saline-treated group (440 +/- 34 microm, p = 2.6 x 10(-6)). By LV angiography, stroke volume was significantly larger in the collagen-treated group (163 +/- 8 microl) than in the saline-treated group (129 +/- 6 microl, p = 0.005), and LV ejection fraction was also greater in the collagen-treated group (48.4 +/- 1.8%) than in the saline-treated group (40.7 +/- 1.0%, p = 0.002). Analysis of regional wall motion demonstrated paradoxical systolic bulging in 5 of 10 saline-treated rats that averaged 20.3 +/- 2.6% of the LV diastolic circumference, but in none of the 11 collagen-treated rats (p = 0.012). The LV end-diastolic and end-systolic volumes were 319 +/- 12 microl and 190 +/- 7 microl in the saline-treated group, respectively. There was a trend for larger LV end-diastolic volumes (343 +/- 23 microl), but smaller end-systolic volumes (180 +/- 16 microl) in the collagen-treated group. CONCLUSIONS: This study shows that collagen injection thickens an infarct scar and improves LV stroke volume and ejection fraction, and prevents paradoxical systolic bulging after myocardial infarction.

Animals↗
PubMed1997

Renal function in the elderly: impact of hypertension and cardiac function.

In senescence renal function is thought to decline markedly even in the absence of renal disease. It has also been proposed that the changes in renal function with age are not uniform and that confounding factors such as hypertension or atherosclerosis may play a role. We performed a comprehensive study to compare several aspects of renal function in four groups: (i) young healthy normotensive subjects (N = 24; 13 males; mean age 26 +/- 3 years); (ii) elderly healthy normotensive subjects (elderly NT; N = 29; 13 males; 68 +/- 7 years); (iii) elderly treated and untreated hypertensive patients (elderly HT; N = 25; 13 males; 70 +/- 6 years); and (iv) elderly patients with compensated mild to moderate heart failure (elderly HF; N = 14; 6 males; 69 +/- 6 years). Compared to young subjects mean GFR (C(In)) and ERPF (C(PAH)) were significantly lower in the elderly, despite similar mean plasma creatinine levels (young, 121 +/- 11, 650 +/- 85 ml/min/1.73 m2; elderly NT, 103 +/- 11, 486 +/- 102; elderly HT, 103 +/- 13, 427 +/- 55; elderly HF, 92 +/- 14, 377 +/- 103). Nevertheless, GFR was within the normal range in the majority of elderly NT and HT, but not in elderly HF. ERPF was significantly lower in elderly HT as compared with elderly NT, and still lower in elderly HF. Mean renovascular resistance and filtration fraction were significantly higher in the elderly, particularly in elderly HT and HF as compared with the young. Mean fractional excretion of Na+ was similar in all groups studied, but the lithium clearance was significantly lower in the elderly, suggesting a greater proximal and less distal sodium reabsorption in senescence. In the elderly, mean PTH concentration and urinary excretion of pyridoline cross-links were significantly higher and mean 25-(OH)D3, calcitriol and phosphate concentrations significantly lower; the correlation between PTH and GFR was significant (r = -0.432, P < 0.001). The results document that the decrease in renal hemodynamics with senescence is less marked than suggested by some studies using less stringent methodology and inclusion criteria. Comorbid conditions confound renal function in the elderly. Age-associated changes in renal hemodynamics are accompanied by significant alterations of renal hormones and of renal sodium handling.

Adult↗
PubMed1991

A computer-assisted image processing method for determining relative cardiac function in the chick embryo.

The general objective of this study was to develop a noninvasive method for efficiently and reproducibly determining relative cardiac function parameters in the chick embryo. The specific objectives of the study were 1) to develop several methods for computer-assisted image processing and quantitation of relative intraventricular blood volumes in the 3-day-old embryonic chick heart and 2) to compare methods for precision and with a previously established manual processing method. Images of the embryonic chick heart in ovo were recorded on videocassette tape, digitized, and enhanced by computer-aided histogram equalization. The area occupied by blood within the common ventricle was extracted by region-growing and spurious region removal algorithms and defined by the determination of edge-pixel coordinates. Edge-pixel coordinates of the longitudinal and transverse axes of the common ventricular blood region were located by three different methods, the lengths of the axes calculated, and volumes computed from the equation for determining volume of a prolate spheroid. Twenty-five images of the embryonic heart were randomly selected and processed. Volumes were calculated with each of the three methods on six different occasions. A coefficient of variation was calculated for each method. The intraobserver mean coefficient of variation for each method was 7.4%. When a 2-way ANOVA was conducted, mean coefficients of variation did not differ significantly for the three methods. However, computer processing (in addition to significantly reducing the time required to generate data) reduced the coefficient of variation observed in manual processing by 56.5%.

Analysis of Variance↗
PubMed1994

Subclinical disturbances in cardiac function at rest and in gas exchange during exercise are common findings after autologous bone marrow transplantation.

A study was undertaken to examine the effects of autologous bone marrow transplantation (BMT) on cardiac function at rest (n = 111) and pulmonary gas exchange during exercise (n = 110). Left ventricular cardiac ejection fraction (LVEF) was measured by radionuclide ventriculography before autologous BMT and after 6 months and 1, 3 and 5 years. Expired gas volume per oxygen consumption (VE/VO2) and transcutaneous PO2 were measured at rest and during submaximal exercise before and 6 and 12 months after autologous BMT, and the alveolar-arterial oxygen difference was calculated after 12 months. In lymphoma patients conditioned with BCNU, cyclophosphamide, etoposide and cytarabine, a long-lasting reduction in LVEF of 11 +/- 14% mean (+/- SD) was noted. The risk of cardiac deterioration was not increased by a subnormal LVEF before autologous BMT or total body irradiation (TBI). Impaired gas exchange during exercise was a common feature, but severe disturbances were uncommon. During exercise transcutaneous PO2 fell pathologically in 15% and 20% of the patients examined after 6 and 12 months, respectively, and the alveolar-arterial oxygen difference increased pathologically in 50% after 12 months. The VE/VO2 ratio increased significantly during exercise 6 months after autologous BMT in TBI-treated patients.

Adolescent↗
PubMedDate not supplied

Recovery of cardiac function after standard hypothermic storage versus preservation with Peg-hemoglobin.

Preservation of the heart for transplantation after infusion of cardioplegia and extirpation of a cardiac allograft results in an ischemic insult to the myocardium. This ischemic insult may lead to a loss of function in the transplanted heart. Hypothermic perfusion preservation with an oxygen hemoglobin carrying solution may avert ischemic injury and lead to improved recovery of cardiac function. The purpose of this study was to compare cardiac function after 8 hours of continuous hypothermic perfusion with a unique polyethylene-glycol-hemoglobin (PEG-Hb) solution to hearts preserved by 4 hours of hypothermic ischemic storage. Freshly extirpated hearts served as functional controls. The hearts of 26 anesthetized and intubated New Zealand white rabbits were harvested after cold cardioplegic arrest. Group I (n = 12) hearts were perfused with a PEG-Hb solution at 20 degrees C and 30 mm Hg for 8 hours. PO2 was maintained > or = 500 mm Hg. Group II (n = 7) hearts were preserved by cold ischemic storage for 4 hours at 4 degrees C. Group III (n = 7) were tested immediately after harvest. Left ventricular (LV) function was measured in the nonworking state at 15 minutes, 1 hour, and 2 hours after transfer to a standard crystalloid Langendorff circuit. Measurement of LV developed pressure, peak + dP/dt and -dP/dt revealed a superior trend between Group I and Group II hearts in comparison with freshly extirpated hearts. Heart rate was similar among all groups throughout testing (p = ns). Coronary blood flow was not significantly different between groups. Continuous perfusion preservation of rabbit hearts for 8 hours with PEG-Hb solution at 30 mm Hg and 20 degrees C yielded LV function that was similar to 4 hours of ischemic hypothermic storage. Furthermore, return of cardiac function after 8 hours of perfusion preservation using this PEG-Hb solution may be superior to that obtained in freshly extirpated hearts. These data suggest that some recovery of myocardial function may occur during perfusion preservation with this PEG-Hb solution after the ischemic insult of cardioplegic arrest. Continuous perfusion preservation using this PEG-Hb solution deserves further investigation in large animal transplant models.

Animals↗