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PubMed1990

Effects of pyridoxalated hemoglobin polyoxyethylene conjugate and stroma-free hemoglobin on cardiac function in isolated rat heart.

Effects of a newly introduced modified hemoglobin, pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), and stroma-free hemoglobin (SFH) on cardiac rhythm and contractility were examined in isolated rat hearts. Hearts were perfused with HEPES-buffered Krebs solution containing 6% PHP, 6% SFH, or 6% hydroxyethylstarch (HES). Arrhythmia was not observed in PHP-perfused hearts, but marked sinus bradycardia occurred in SFH-perfused hearts. Ventricular contractility assessed by left ventricular pressure and pressure-volume relationship in both PHP and SFH-perfused hearts were well maintained during perfusion. There was no significant difference to the coronary flow resistance between hearts perfused with PHP and HES solutions, indicating that PHP has little vasoactive effect. The flow resistance in SFH-perfused hearts decreased significantly when compared with other groups. Results demonstrate that PHP solution can preserve cardiac function and have no toxic effects in isolated rat hearts.

Animals↗
PubMed1995

[Relationship between 123I-BMIPP imaging and cardiac function in acute myocardial infarction].

We evaluated the relationship between free fatty acid metabolism using 123I beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and cardiac function in acute myocardial infarction. Twenty-five patients were examined with 123I-BMIPP and 201Tl dual SPECT. The 123I-BMIPP images were compared with the 201Tl images and the left ventricular wall motions. The 123I-BMIPP images showed a larger uptake defect than the 201Tl images. This was marked in the patients after revascularization therapy. The uptake decrease of 123I-BMIPP was in good agreement with the decrease in regional wall motion. The incidence of accordance was 79% of the wall segments. The correlation between 123I-BMIPP defect size and ejection fraction was higher (r = -0.54) than that of 201Tl (r = -0.44). Subtraction of ejection fractions four weeks and soon after infarction correlated well with the subtraction of 123I-BMIPP and 201Tl defect sizes (r = 0.55). In conclusion, 123I-BMIPP is more closely related to wall motion, than 201Tl and might be valuable in predicting the functional improvement of acute myocardial infarction.

Adult↗
PubMed1984

Radionuclide assessment of cardiac performance in cystic fibrosis. Reproducibility and effect of theophylline on cardiac function.

A study was designed to evaluate the reproducibility of right and left ventricular ejection fraction measurements (RVEF, LVEF) by equilibrium radionuclide angiography in cystic fibrosis (CF) and to determine the effect of the acute administration of aminophylline on RVEF and LVEF in this disease. Both RVEF and LVEF were measured at rest and during incremental supine bicycle exercise by equilibrium radionuclide angiography in 18 patients with CF. In 9 of these patients, radionuclide studies were repeated after an infusion of aminophylline (9 mg/kg), whereas the remaining patients had radionuclide studies repeated after a placebo infusion. No significant increase in mean RVEF or LVEF values either at rest or at peak exercise was seen after aminophylline infusion. In the patients who underwent sequential radionuclide studies without intervening active drug intervention, the mean (+/- standard deviation) variability in RVEF and LVEF measurements between the 2 studies was 2.6 +/- 2% and 3.6 +/- 2.9%, respectively. We conclude that (1) equilibrium radionuclide angiography is a reasonably reproducible technique for serial assessment of biventricular function at rest and during exercise in CF, and that (2) the acute administration of aminophylline does not augment cardiac function either at rest or during exercise in this disease.

Adolescent↗
PubMed1992

Clinical evaluation of cardiac function by ambulatory ventricular scintigraphic monitoring (VEST): validation and study of the effects of nitroglycerin and nifedipine in patients with and without coronary artery disease.

Global left ventricular function and ECGs were continuously monitored by radionuclide ambulatory ventricular function monitoring (VEST) and validated against multigated blood pool analysis (MUGA) and left ventriculography in 26 subjects (study 1). Ejection fraction by VEST (Y) showed good correlation with Y = 5.5 +/- 0.79 X (r = 0.91), Y = 1.7 +/- 0.86 X' (r = 0.91), and Y = 11.6 + 0.68 X" (r = 0.82) to sitting and supine MUGA and left ventriculography, respectively. In study 2 left ventricular function and ECGs were evaluated at rest and during exercise without any drug (control), with nitroglycerin, and with nifedipine in 21 patients with coronary disease (group I) and six normal subjects (group II). In group I abnormal ejection fraction responses (exercise increase less than or equal to 6%) during the control exercise period were found in 15 patients (71%), ST segment abnormalities in seven (33%), and chest pain in four (18%). Control exercise increased end-diastolic volume (100 to 112 +/- 8%) and end-systolic volume (53 +/- 15% to 63 +/- 22%) and decreased the ejection fraction (47 +/- 15% to 43 +/- 21%). The ejection fraction during exercise increased after nitroglycerin (50 +/- 22%) or nifedipine (54 +/- 21%) (p less than 0.05). In group II the ejection fraction was unchanged between rest and exercise with or without nitroglycerin or nifedipine. Thus combined radionuclide and ECG monitoring by VEST could detect changes in left ventricular function at rest and during exercise over a prolonged period and demonstrated that nitroglycerin and nifedipine improved cardiac function in the ischemic setting with an increased ejection fraction in the upright position.

Coronary Disease↗
PubMed1983

Short-term responses to cardiac rehabilitation after acute myocardial infarction. Cardiac function evaluation before and after physical training at rest and during stress test.

Whether physical training, soon after myocardial infarction (MI), has effects upon intrinsic cardiac function at rest and during exertion remains unresolved. We have evaluated ventricular function using radionuclide angiography at rest and during stress testing before and after 3 months' physical training. This has been correlated with the site of MI and with changes in the ST segment during the maximal exercise test performed before the postmyocardial infarction rehabilitation program. We have studied 27 patients, mean age 54 +/- 10 years, in NYHA class I or II. Twelve showed no changes in the ST segment during erogmetric stress test (group 1); seven showed ST segment depression greater than 1 mm in leads different from those of MI (group 2); eight showed ST segment elevation of 2 mm (group 3). Twelve patients had had anterior MI only (AMI group); twelve inferior MI only (IMI group). After rehabilitation, all patients showed an increased work capacity and a decreased double product at the same work load. In the total group, significant increases were found in the left ventricular ejection fraction (LVEF) and in the contractile regional performance (LVwm) at rest, as well as a lesser decrease in the LVEF during handgrip test. Group 1 showed a significant increase in LVEF, associated with a decrease in left ventricular end-diastolic volume (EDV) at rest. Group 2 showed unchanged variables after rehabilitation. Group 3 showed a better LVEF during handgrip with an increase of EDV at rest. The AMI group showed a better LVEF and LVwm at rest and a better LVEF during handgrip. IMI group showed a better right ventricular ejection fraction during handgrip without improvement in LVEF. No patient with IMI had septal asynergy. We conclude that the effects of rehabilitation were linked to the site of MI and to the functional dynamic status of both ventricles.

Electrocardiography↗
PubMed1990

Systemic hemodynamic and cardiac function changes in patients undergoing orthotopic liver transplantation.

The objective of this study was to determine the changes in systemic hemodynamics (systemic vascular resistance [SVR], cardiac output [CO], systemic blood pressure [SBP]) and cardiac function (pulmonary artery pressure [PAP] and pulmonary wedge pressure [PWP]) during the 96 hours following orthotopic liver transplantation (OLT) and correlate these with changes in hepatic and renal function and patient outcome. The study took place in a 12-bed medical respiratory intensive care unit in a large teaching hospital. Twenty-one patients had OLT performed over a 21.5-month period (January 1988 to October 15, 1989) for end stage liver disease (ESLD) from a variety of causes. A flow-directed right heart catheter and an indwelling arterial cannula were inserted for hemodynamic monitoring over a 96-hour postoperative period. Liver and renal function studies, total serum calcium, serum albumin, and fluid balance were determined daily. The SVR increased significantly to 12.8 +/- 0.6 U at 48 hours compared with immediate (less than 8 hours) postoperative levels (p less than 0.05) and remained elevated for 96 hours. The CO fell progressively and was significantly lower than baseline values from 64 to 96 hours. There was significant inverse correlation between the increase in SVR and the fall in CO (r = .85, p less than 0.01). The SBP was stable except for a small, but significant fall at 16 and 24 hours postoperatively. The PWP increased significantly from a baseline value of 12.5 +/- 0.9 mm Hg to 15 +/- 0.9 mm Hg at 32 hours and remained elevated through 96 hours (p less than 0.05). The serum bilirubin level fell progressively postoperatively and the prothrombin time and partial thromboplastin time (PTT) shortened significantly. Bile flow increased progressively from 107 +/- 120 ml/24 hours at the end of the first 24 hours to 188 +/- 125 ml/24 hours by 96 hours postoperatively. Five patients died from nine to 43 days postoperatively. These patients' hemodynamic parameters were not significantly different from the patients who survived. Successful OLT is associated with a rapid increase in SVR and a fall in CO without changes in SBP. These findings tend to parallel the improvement found in results of liver function tests. However, there is no correlation between the improvement in the hemodynamic state and long-term survival.

Adult↗
PubMed1991

Early adaptations in gas exchange, cardiac function and haematology to prolonged exercise training in man.

In order to determine the effect of short-term training on central adaptations, gas exchange and cardiac function were measured during a prolonged submaximal exercise challenge prior to and following 10-12 consecutive days of exercise. In addition, vascular volumes and selected haematological properties were also examined. The subjects, healthy males between the ages of 19 and 30 years of age, cycled for 2 h per day at approximately 59% of pre-training peak oxygen consumption (VO2) i.e., maximal oxygen consumption (VO2max). Following the training, VO2max (l.min-1) increased (P less than 0.05) by 4.3% (3.94, 0.11 vs 4.11, 0.11; mean, SE) whereas maximal exercise ventilation (VE,max) and maximal heart rate (fc,max) were unchanged. During submaximal exercise, VO2 was unaltered by the training whereas carbon dioxide production (VE) and respiratory exchange ratio were all reduced (P less than 0.05). The altered activity pattern failed to elicit adaptations in either submaximal exercise cardiac output or arteriovenous O2 difference. fc was reduced (P less than 0.05). Plasma volume (PV) as measured by 125I human serum albumin increased by 365 ml or 11.8%, while red cell volume (RCV) as measured by 51chromium-labelled red blood cells (RBC) was unaltered. The increase in PV was accompanied by reductions (P less than 0.05) in haematocrit, haemoglobin concentration (g.100 ml-1), and RBCs (10(6) mm-3). Collectively these changes suggest only minimal adaptations in maximal oxygen transport during the early period of prolonged exercise training. However, as evidenced by the changes during submaximal exercise, both the ventilatory and the cardiodynamic response were altered.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMedDate not supplied

Improved recovery of cardiac function after 24 h of hypothermic arrest in the isolated rat heart: comparison of a prostacyclin analogue (ZK 36 374) and a calcium entry blocker (diltiazem).

The effects of a stable prostacyclin analogue (ZK 36 374; 4 nM) and a calcium entry blocker (diltiazem; 50 nM) on the recovery of cardiac function after 24 h of hypothermic (10 degrees C) cardiac arrest were studied in the isolated rat heart. Recovery of the pressure-rate index of treated hearts was significantly better [59 +/- 10% for diltiazem (p less than 0.05) and 51 +/- 7% for ZK 36 374 (p less than 0.05)] than in untreated hearts (27 +/- 9%). Untreated hearts had second- and higher-degree atrioventricular block, with an average ventricular rate of 60 +/- 6% of control. All drug-treated hearts, however, were in sinus rhythm at their initial frequency without a significant alteration in PQ interval. Moreover, the incidence of severe arrhythmias was significantly reduced by ZK 36 374 (p less than 0.02) and diltiazem (p less than 0.01). ZK 36 374 reduced total purine overflow upon reperfusion (503 +/- 51 vs. 223 +/- 22 nmol min-1 g dry weight-1; p less than 0.0005). The delayed overflow of adenosine, a proposed marker of reperfusion damage, was not affected by ZK 36 374 treatment. In contrast, diltiazem had no effect on total purine overflow upon reperfusion, but nearly abolished delayed adenosine overflow. It is concluded from these results that both ZK 36 374 and diltiazem improve myocardial recovery after 24 h of hypothermic cardiac arrest.

Adenosine↗
PubMed1980

Exercise capacity and cardiac function in trained and untrained thyroid-deficient rats.

This study was undertaken to ascertain the extent that impairments in a) the oxidative capacity of skeletal muscle, b) cardiac functional and biochemical correlates of contractile capacity, and c) maximal oxygen consumption (VO2 max) can be reversed in thyroid-deficient (TD) female rats subjected to an 8-wk physical training (running) program. Compared with a normal control (NC) group, thyroid deficiency caused reductions in the following: VO2 max (-32%), skeletal muscle homogenate respiratory capacity (-50%), cardiac myosin ATPase (-58%), and in situ-derived ventricular dP/dt max (-58%) (P < 0.001). The training program restored to within normal limits skeletal muscle oxidative capacity and VO2 max, but it did not improve cardiac myosin ATPase, Ca2+ regulation of myofibril ATPase, and dP/dt max relative to TD sedentary rats. However, the heart weight-to-body weight ratio was highest among the three groups in the TD trained group. These findings suggest that maximal oxygen utilization capacity of TD rats can be normalized by physical training, even though intrinsic contractile capacity of the heart could not.

Adenosine Triphosphatases↗
PubMed1985

Effects of intracoronary and intravenous amrinone infusions in patients with cardiac failure and patients with near normal cardiac function.

The effects of intracoronary and intravenous infusions of amrinone were studied to distinguish the drug's direct cardiac actions from its peripheral vascular and neuroendocrine properties. Intracoronary infusions of amrinone were found to have no haemodynamic effect other than producing a slight reduction in the left ventricular ejection fraction and some suggestion of coronary vasodilatation in patients with impaired left ventricular function. They did not improve contractility, cardiac output, or filling pressures and had no significant effect on myocardial metabolism, although therapeutic concentrations of the drug were detected in coronary sinus blood. Intravenously administered amrinone reduced filling pressures and improved the cardiac index in all patients, but haemodynamic improvements were most pronounced in the patients with the worst cardiac function. These changes were accompanied by improvements in the indices of contractility only in patients in whom alterations in concentrations of free fatty acid, glycerol, and glucose suggested peripheral catecholamine release. In the patients with the best basal cardiac function intravenously administered amrinone produced a reduction in myocardial work and evidence of myocardial ischaemia, as a result of excessive reduction of coronary perfusion pressure and increased heart rate, without any appreciable increase in cardiac index. It is concluded that, at the concentrations of the drug that can be achieved in man without adverse effects, amrinone has no direct positive inotropic effect. Haemodynamic changes are predominantly the result of vasodilatation, although catecholamines may be released in some patients.

Adult↗
PubMed1990

Effects of metoprolol on rest and exercise cardiac function and plasma catecholamines in chronic congestive heart failure secondary to ischemic or idiopathic cardiomyopathy.

To define the effects of 2 months of metoprolol therapy on cardiac function, aerobic performance and sympathetic nervous system activity, metoprolol (75 to 100 mg/day) was administered to 10 patients with chronic congestive heart failure (CHF). Metoprolol was discontinued in 2 patients because of worsening CHF. In the remaining 8 patients, peak oxygen uptake increased significantly (14.8 +/- 3.0 to 16.1 +/- 2.5 ml/kg/min, p less than 0.05) as did the oxygen pulse (9.0 +/- 2.2 to 12.6 +/- 1.8 ml/beat, p less than 0.02). Resting heart rate (87 +/- 18 to 62 +/- 9 beats/min, p less than 0.05) and peak exercise heart rate (133 +/- 13 to 105 +/- 30 beats/min, p less than 0.02) were both reduced. Mean resting ejection fraction increased from 0.15 +/- 0.06 to 0.25 +/- 0.11 and peak exercise ejection fraction also tended to increase (0.19 +/- 0.11 to 0.28 +/- 0.15, difference not significant). Both resting plasma norepinephrine (613 +/- 706 to 303 +/- 142 pg/ml, p less than 0.05) and epinephrine (71 +/- 50 to 40 +/- 21 pg/ml, p less than 0.05) were reduced. Circulating lymphocyte beta-adrenergic receptor number was unchanged (1,334 +/- 292 to 1,344 +/- 456 receptors/cell, difference not significant). It is concluded that metoprolol therapy is associated with improvements in rest and exercise ventricular performance and maximal aerobic capacity. These improvements are associated with a decline in resting sympathetic nervous system activity.

Aged↗
PubMed1995

Cardiac function in smokers and nonsmokers: the CARDIA study. The Coronary Artery Risk Development in Young Adults Study.

OBJECTIVES: This study assessed clinical and echocardiographic measures of cardiac function at rest in smokers and nonsmokers to determine the associations of cigarette smoking with various measures of left and right ventricular performance. BACKGROUND: Whereas the immediate cardiovascular effects of cigarette smoking have been well described, the long-term effects in an otherwise healthy cohort have not. Of particular interest were associations with heart rate, left ventricular end-systolic stress and left ventricular mass because higher levels of these measures would suggest increased myocardial oxygen consumption. METHODS: In year 5 of the Coronary Artery Risk Development in Young Adults (CARDIA) study, 3,366 smokers and nonsmokers (ex-smokers were excluded) underwent echocardiography as well as assessment of heart rate, anthropometric measurements and blood pressure. Participants ranged in age from 23 to 35 years and were equally distributed by race and gender. Echocardiographic measures included pulsed Doppler pulmonary artery acceleration time (a decrease suggests increased pulmonary artery pressure), left ventricular mass, left ventricular end-systolic stress and left ventricular fractional shortening. RESULTS: All comparisons were between smokers and nonsmokers. Heart rate at rest was significantly higher in smokers by 1.5 to 5 beats/min in all race/gender groups except black men. In men who smoked, pulmonary artery acceleration time was significantly lower by 4 to 8 ms. Except for black male smokers, there was a trend toward increased left ventricular mass (3 to 8 g) in all race/gender groups, significant in black women. Left ventricular end-systolic stress was significantly higher in women who smoked (4 to 6 dynes/cm2). There were no differences for systolic blood pressure or left ventricular fractional shortening. CONCLUSION: In an assessment of cardiovascular function at rest in young adults, quantifiable differences between smokers and nonsmokers that predict increased rest myocardial oxygen consumption in smokers were found. Some of these differences were gender specific.

Adolescent↗
PubMed1991

Alterations in cardiac function and subcellular membrane activities after hypervitaminosis D3.

The present study was designed to induce massive accumulation of calcium in the myocardium and to evaluate the effect of calcium overload on myocardial contractile function and biochemical activity of cardiac subcellular membranes. Rats were treated with an oral administration of 500,000 units/kg of vitamin D3 for 3 consecutive days, and their hearts were sampled on the 5th day for biochemical analysis. On the 4th and 5th days, heart rate, mean aortic pressure, left ventricular systolic pressure and left ventricular dP/dt were significantly lowered in vitamin D3-treated rats, demonstrating the existence of appreciable myocardial contractile dysfunction. Marked increases in the myocardial calcium (67-fold increase) and mitochondrial calcium contents (24-fold increase) were observed by hypervitaminosis D3. Mitochondrial oxidative phosphorylation and ATPase activity were significantly reduced by this treatment. A decline in sarcolemmal Na+, K(+)-ATPase activity was also observed, while relatively minor or insignificant changes in calcium uptake and ATPase activities of sarcoplasmic reticulum were detectable. Electron microscopic examination revealed calcium deposits in the mitochondria after vitamin D3 treatment. The results suggest that hypervitaminosis D3 produces massive accumulation of calcium in the myocardium, particularly in the cardiac mitochondrial membrane, which may induce an impairment in the mitochondrial function and eventually may lead to a failure in the cardiac contractile function.

Adenosine Triphosphatases↗
PubMed1992

[Correlation analysis between plasma atrial natriuretic peptide and cardiac function in blood deficiency syndrome].

The function of ANP in the cardiovascular regulation is very similar with the TCM theory of "the Heart governs blood circulation". Using the method of cardiac impedance to check cardiac output and the method of radioimmunoassay (RIA) to check plasma ANP, the result showed that in the status of Blood Deficiency Syndrome, cardiac function was impaired, there were reduced kinemia and stroke volume, as well as markedly raised plasma ANP and peripheral resistance. The above-mentioned indexes were significantly different from those of normal group (P < 0.01). Using multivariate regression analysis, cardiac output was negatively correlated with the plasma ANP (P < 0.05). 23 cases with Blood Deficiency Syndrome showed normal hemoglobin, but an evidently changed cardiac output and plasma ANP were closely related with the level of the Blood Deficiency. Both parameters might serve as the objective basis to reflect the level of Blood Deficiency to facilitate the clinical diagnosis of the patient.

Adult↗
PubMed1990

[Cardiac function and reactivity in the late period following irradiation with high-energy protons].

Electrocardiography was used to analyze the results of 4-year investigations of the cardiac activity and reactivity (adrenalin test) in 32 dogs irradiated with high-energy protons (approximately 240 MeV) at absolutely lethal doses of 4 and 5 Gy. The author's and literature data have shown the similarity of cardiac functional features and reactivity in a long-term period in dogs with those in animals after radiation disease caused by exposure to some other types of ionizing radiations.

Acute Disease↗
PubMed1995

[The relationship between the improvement of cardiac function and the myocardial uptake of I-123 metaiodobenzylguanidine in patients with dilated cardiomyopathy treated by beta-blocker].

Chronic beta-blocker therapy improves hemodynamics and cardiac function in patients with idiopathic dilated cardiomyopathy. However, the change in myocardial uptake of I-123 metaiodobenzylguanidine (123I-MIBG) before and after treatment has not been determined. Myocardial imaging with 123I-MIBG was performed before and 2 or 3 months after beta-blocker (bisoprolol) therapy in 11 patients with dilated cardiomyopathy. The following parameters were compared before and after the treatment: 1) New York Heart Association functional class, 2) X-ray cardiothoracic ratio, 3) heart rate and blood pressure, 4) echocardiographic data (left ventricular end-diastolic and end-systolic diameters, and left ventricular ejection fraction), 5) plasma concentrations of epinephrine, norepinephrine and human atrial natriuretic peptide (HANP), and 6) exercise tolerance time by treadmill. The heart-to-mediastinum ratio of 123I-MIBG activities obtained 3 hours after intravenous injection (late H/M) and washout rate improved significantly after beta-blocker therapy. Cardiothoracic ratio, heart rate, echocardiographic parameters, HANP and exercise tolerance also improved significantly. Late H/M had no significant relationship with any of the clinical parameters, but washout rate was significantly related to left ventricular ejection fraction. These findings suggest that washout rate may be useful to assess the effect of short-term beta-blocker therapy in dilated cardiomyopathy patients.

3-Iodobenzylguanidine↗
PubMed2024

The multifaceted role of mitochondria in cardiac function: insights and approaches.

Cardiovascular disease (CVD) remains a global economic burden even in the 21st century with 85% of deaths resulting from heart attacks. Despite efforts in reducing the risk factors, and enhancing pharmacotherapeutic strategies, challenges persist in early identification of disease progression and functional recovery of damaged hearts. Targeting mitochondrial dysfunction, a key player in the pathogenesis of CVD has been less successful due to its role in other coexisting diseases. Additionally, it is the only organelle with an agathokakological function that is a remedy and a poison for the cell. In this review, we describe the origins of cardiac mitochondria and the role of heteroplasmy and mitochondrial subpopulations namely the interfibrillar, subsarcolemmal, perinuclear, and intranuclear mitochondria in maintaining cardiac function and in disease-associated remodeling. The cumulative evidence of mitochondrial retrograde communication with the nucleus is addressed, highlighting the need to study the genotype-phenotype relationships of specific organelle functions with CVD by using approaches like genome-wide association study (GWAS). Finally, we discuss the practicality of computational methods combined with single-cell sequencing technologies to address the challenges of genetic screening in the identification of heteroplasmy and contributory genes towards CVD.

Humans↗