Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cardiac function”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1992

Depressed systolic and diastolic cardiac function after prolonged aerobic exercise in healthy subjects.

We studied 11 healthy untrained volunteers (aged 28.9 +/- 4.6 years) during 60 minutes of aerobic ergometric exercise with constant heart rates of 130 to 140 beats/minute. We found a continuous and significant decrease in systolic and diastolic pressure from 175 +/- 18/77 +/- 7 mmHg in the 5th minute to 144 +/- 14/68 +/- 6 mmHg in the 60th minute of exercise. Cardiac function and structure were assessed by M-mode echocardiography before exercise, after 5 minutes and after 60 minutes of exercise at comparable heart rates. The results demonstrated significant decreases in cardiac output, ejection fraction, and diastolic posterior wall velocity and an increase in total peripheral resistance after 60 minutes of exercise. We conclude that the decrease in blood pressure during long-term aerobic exercise in healthy untrained subjects might be at least influenced by a decrease in left ventricular filling and contractility, possibly indicating cardiac fatigue.

Adult↗
PubMed1977

[Nervous regulation of cardiac function during aging].

The hemodynamic changes and myocardium contractile capacity following the extracardiac nerves stimulation with acetylcholine, norepinephrine, inderal, regitin and atropine, as well as the activity of main enzymes of cholinergic and adrenergic metabolism, were studied in albino rats, rabbits, and cats of various age. With ageing, the thresholds of vagal and sympathetic nerves influences on the heart increased, the sensitivity of heart to acetylcholine and norepinephrine changed. In old animals, smaller atropine and in deral doses blocked the respective cholinergic and beta-adrenergic reactions. Alterations of transmitters metabolism play an important role in the mechanism of age-induced changes in nervous control of cardiac function.

Acetylcholine↗
PubMed1992

Evaluation of quinapril on regional blood flow and cardiac function in patients with congestive heart failure.

Quinapril, a nonsulfhydryl ACE inhibitor, was evaluated in ten New York Heart Association (NYHA) functional class (FC) II-III CHF patients to determine its effects on regional blood flow [effective renal plasma flow (ERPF), renal blood flow (RBF), renal vascular resistance (RVR), hepatic blood flow (HBF), hepatic vascular resistance (HVR), segmental limb pressure (SLP), creatinine clearance (CRCL)] and cardiac function [left ventricular ejection fraction (LVEF)]. Previous vasodilator therapy was withdrawn 2 weeks before baseline measurements. Stable regimens of digoxin and diuretics were continued throughout the study. ERPF was assessed using p-aminohippurate (PAH), HBF by indocyanine green (ICG) clearance, and LVEF by radionuclide scintography. Segmental limb pressures were measured by Doppler flow detection. Measurements were performed at baseline (B) and after 4 weeks of quinapril therapy (10 mg BID). Quinapril increased renal (P less than 0.05) and hepatic blood flow (P = 0.06) and significantly reduced renal and hepatic vascular resistance. Glomerular filtration rate and left ventricular ejection fraction were unchanged. Mean arterial pressure and brachial segmental pressures decreased without change in heart rate. Noninvasive cardiovascular assessments indicate that quinapril improves regional blood flow while exhibiting no change in left ventricular ejection fraction, in patients with NYHA FC II-III CHF.

Antihypertensive Agents↗
PubMed1992

Effect of flosequinan on exercise capacity and cardiac function in patients with chronic mild heart failure: a double-blind placebo-controlled study.

Although beneficial effects of a new vasodilating agent, flosequinan, have been demonstrated in patients with severe heart failure, its efficacy has not been studied in patients with a less severe form of chronic heart failure. In this study, the effects of 4 weeks' administration of flosequinan, 50 mg daily, and placebo on exercise capacity, cardiac function, and symptoms of heart failure were investigated in 24 patients with chronic mild heart failure (New York Heart Association functional class, mainly class II) in a double-blind clinical trial. When the parameter changes during the treatment period of the flosequinan and placebo groups were compared, no significant difference was found in any of the measurements except for left ventricular fractional shortening determined from M-mode echocardiograms; it was increased by 2.9 +/- 1.3% in the flosequinan group whereas it was decreased by 1.3 +/- 0.9% in the placebo group (P less than 0.05 vs flosequinan treatment). However, when compared to baseline values, flosequinan significantly increased exercise time in the symptom-limited maximal exercise test (704 +/- 103 to 763 +/- 107 s, P less than 0.05) and the oxygen uptake at the anaerobic threshold (13.8 +/- 1.3 to 16.7 +/- 1.4 ml/min kg, P less than 0.05), and improved symptoms assessed with a new heart failure severity classification (a median value of 2.0-1.5, P less than 0.05). These improvements were not observed in the placebo group. Serious adverse effects were not observed in either group. These results suggest that flosequinan is useful for the treatment of chronic mild heart failure as well as severe heart failure.

Adult↗
PubMed1992

Combined invasive and noninvasive study of left ventricular systolic and diastolic function following acute administration of cicloprolol to subjects with normal cardiac function.

Cicloprolol is a new beta-blocking agent with high selectivity for beta 1 receptors and high intrinsic sympathomimetic activity. We studied the acute hemodynamic effects of cicloprolol in nine subjects with no evidence of left ventricular dysfunction who underwent cardiac catheterization for the evaluation of chest pain. All patients had normal coronary angiography and left ventriculography. Left ventricular pressure was determined throughout the cardiac cycle using a Millar 8Fr Minotip catheter; an echocardiogram, phonocardiogram, and ECG were simultaneously recorded to obtain left ventricular pressure-diameter loops. All the measurements were repeated before and after the intravenous administration of cicloprolol. Cicloprolol was administered at increasing doses of 0.05, 0.10, and 0.25 mg/kg until a cardiac output increase of at least 15% over basal values was achieved. A decrease of mean arterial pressure or cardiac output after cicloprolol was not observed in any patient. Cicloprolol administration significantly increased cardiac output (24%), stroke volume (22%), and peak positive dP/dt (25%); no significant changes in heart rate, systemic blood pressure, right atrial pressure, or pulmonary artery pressures were observed. No significant change in the echocardiographic parameters occurred. Among the indices of left ventricular diastolic function, the time constant of isovolumetric relaxation was significantly decreased (-43%) after cicloprolol; moreover, the left ventricular pressure-diameter loop in the protodiastolic phase was shifted to the left following cicloprolol infusion. This study confirms that in subjects with normal left ventricular function cicloprolol can improve resting left ventricular systolic function, and it shows that this action can also be attended by a more rapid isovolumetric relaxation, similar to what has been observed with other sympathomimetic amines.

Adrenergic beta-Agonists↗
PubMed1992

Determinants of left ventricular filling dynamics: alteration in the Doppler-derived transmitral filling profile with progressive impairment of cardiac function in a dog preparation.

To clarify the factors determining transmitral filling, left ventricular and atrial pressures (LVP and LAP) and Doppler-derived diastolic indices were analysed in six anaesthetized dogs at various right atrial pacing rates during dextran infusion. The relationship of the late to early diastolic peak velocity ratio (A/E ratio) to end-diastolic LVP (LVEDP) showed a quadratic curve concave to the LVEDP axis in five animals (r2 = 0.320-0.588). An elevation in LVEDP up to 25 mmHg accompanied an increase in A/E ratio (ascending limb), and further LVEDP elevation caused its inverse decline (descending limb). Multiple regression analysis indicated that A/E ratio correlated positively with maximal LVP, a-wave LAP and heart rate, and negatively with v-wave LAP in both limbs. The time constant of isovolumic LVP decline, which was prolonged as LVEDP was elevated, was a positive correlate of A/E ratio in the ascending limb, but lost its influence on A/E ratio in the descending limb. An elevation in v-wave LAP must have masked the expected effect of left ventricular relaxation abnormality on A/E ratio in this limb. Thus, the transmitral filling profile did not alter unidirectionally, but returned to that seen before volume loading, with a simultaneous progressive impairment of cardiac function.

Animals↗
PubMedDate not supplied

Cardiac function and Fourier phase data from simulated Wolff-Parkinson-White syndrome in a baboon model.

The diagnostic value of Fourier phase analysis and planar scintigraphy in Wolff-Parkinson-White (WPW) syndrome has been suspect. This study investigates phase analytical data from planar radionuclide ventriculography of six baboons with simulated WPW syndrome by means of implanted electrodes. An electrode in the atrium controlled the heart rate and a subsequent stimulation was delivered by electrodes placed at different sites on the ventricles, delayed to cause the characteristic delta wave of the WPW syndrome. Sensitivity for accurately-localizing variously-situated first points of activation (FPAs) from the Fourier phase images was found highest for premature right ventricular (RV) activation, and for atrioventricular (AV) delays around 125 msec. Other sites were subject to artifacts. Changes in cardiac function, phase delay, and histogram parameters were not statistically meaningful.

Animals↗
PubMed1977

Noninvasive assessment of cardiac function and ventricular dyssynergy by precordial Q wave mapping in anterior myocardial infarction.

To determine whether multiple lead precordial electrocardiographic recordings offer an improved index for noninvasive estimation of left ventricular hemodynamic function and segmental dyssynergy, precordial mapping was performed in patients with anterior myocardial infarction, and the number of pathologic Q waves (greater than or equal to 0.04 sec) was counted (Q-Index). Left ventricular function was determined by cardiac catheterization and angiography and correlated with the Q-Index. The Q-Index correlated well with dyssynergy extent (r = 0.84) and inversely with ejection fraction (r= -0.87), stroke work index (r = -0.79) and cardiac index (r = =0.66). Three patient groups were defined by Q-Index; group I, 0.04 sec Q complexes less than 15; group II, 15-25; group III, 26-35. Q-Index related closely to functional classification and survival (mean follow-up 12.2 months): group I, 91%; group II, 81%; group III, 40%. Thus 35-lead precordial Q wave mapping with determination of total number of pathologic Q waves permits practical, atraumatic assessment of hemodynamic and functional status and allows prediction of survival in acute and chronic anterior myocardial infarction.

Adult↗
PubMed1976

Changes in cardiac function during and after pregnancy expressed by systolic time intervals.

Hemodynamic changes during the first and third trimester in pregnancy and in the first week of puerperium were evaluated by non-invasive measurements of Systolic Time Intervals (STI) in supine and left lateral position. The Pre-ejection Period (PEP) was found to shorten significantly in pregnancy and the puerperium due to the increased blood volume. The electro-mechanical systole (QS2) and left ventricular ejection time (LVET) were shortened too, while PEP/LVET-ratio was increased in the third trimester due to the mechanical compression of the gravid uterus on the inferior vena cava. A lengthening of QS2 and LVET and a decreased PEP and P/L-ratio were demonstrated in the third trimester in lateral position when the pressure of the enlarged uterus was eliminated. Heart rate (HR) increased in late pregnancy as well as after delivery, while arterial blood pressure (BP) only underwent minor changes. Employment of the STI seems to provide more useful information about the changes cardiac function during gestation than HR and BP does. The measurements of STI can be repeated without any risk or inconvenience to the patients.

Adult↗
PubMed1977

Cardiac function under myocardial ischemia.

The hemodynamic and metabolic changes, during coronary occlusion and during coronary perfusion with non-oxygenated solution, were studied in anesthetized dogs. Coronary perfusion with non-oxygenated Tyrode's solution was performed through a cannula inserted into the left circumflex coronary artery. Left ventricular peak systolic and end-diastolic pressure (LVSP and LVEDP) were measured, and peak LV-dp/dt/IIP calculated. Stroke volume was measured, and the changed of the local myocardial segment length were recorded by a strain gauge arch sutured on that portion of the myocardium perfused through the left circumflex coronary artery. The efflux of lactic acid into the venous blood from the myocardium perfused through the left circumflex coronary artery was calculated. After 10 sec of coronary occlusion, LVSP, SV, and peak LV-dp/dt/IIP declined; LVEDP elevated and a systolic bulge appeared on the local myocardial segment length curve. There was almost no change in these parameters during 3 min of perfusion with non-oxygenated solution. The efflux of lactic acid was more marked during the perfusion with non-oxygenated solution than during coronary occlusion. The delay of the depression of cardiac function during perfusion with the non-oxygenated solution could be related partly to the "wash-out" of metabolites, such as lactic acid, accumulated in the anoxic myocardium.

Animals↗
PubMed1977

Cardiac function in total anomalous pulmonary venous return before and after surgery.

Cardiac performance was evaluated in 12 infants with isolated total anomalous pulmonary venous return. Four had significant pulmonary venous obstruction and severe pulmonary hypertension (group A). Eight had no obvious venous obstruction, and the pulmonary pressures were lower (group B). In all subjects, right ventricular end-diastolic volume was increased (197% of predicted normal) and its ejection fraction was normal. Left ventricular volume was, generally speaking, still in the normal range (87% of predicted normal); however, its ejection fraction was reduced (0.57 vs normal of 0.73) and left ventricular output was low (3.08 L/min/m2 vs normal of 3.98). Left atrial volume was consistently small (53% of predicted normal) with an appendage of normal size. The infants in group A had smaller chamber volumes/m2 BSA than those in group B. Left atrial function was abnormal, characterized by reduced reservoir function and a greater role as "conduit" from right atrium to left ventricle. Left atrial size was not found to be critical in the surgical repair of TAPVR. Cardiac function is restored to normal following surgery.

Angiocardiography↗
PubMed1992

The protective effect of puerarin against myocardial reperfusion injury. Study on cardiac function.

In order to find out if puerarin could protect the hearts from myocardial reperfusion injury after cardiac arrest, twelve dogs divided into two equal groups were placed on moderately hypothermic cardiopulmonary bypass and their hearts were subjected to 140 min of cold cardioplegic arrest and 60 min of reperfusion. In the control group, the hearts were perfused with a crystalloid cardioplegic solution (CPS) through the aortic root every 20 min during arrest. In the treated group, the hearts received CPS containing puerarin (2 mg/kg). Cardiac hemodynamic variables were monitored throughout the experiments. Left ventricular function curves were formed before ischemia and after 60 min of reperfusion. The results showed that the recovery of left ventricular function in the treated group was significantly better than that in the controls (81 +/- 11% versus 39 +/- 7%, P less than 0.01). Compared with preischemic values, the increase of coronary blood flow (CBF) at cardiac arrest in the puerarin-treated group was higher than that in the control group (214 +/- 11 versus 177 +/- 4 ml/min, P less than 0.01). The data indicate that puerarin has protective effects on the cardiac function after prolonged arrest and reperfusion.

Animals↗
PubMed1977

Cardiac function, coronary flow and MVO2 in hypertrophy induced by pressure and volume overloading.

Myocardial function, flow and O2 consumption were compared in cardiac hypertrophy induced by pressure-loading (P) and by volume overloading (V). Increases in LV-to-body weight ratios in P and V hypertrophied hearts were comparable. Indices of LV function such as cardiac output, stroke volume, stroke work, minute work, peak LV dP/dt, ratio of peak LV dP/dt-to-isovolumic pressure and -to-LVEDP, and Vmax were significantly reduced from normal only in hypertrophy induced by V. Left ventricular coronary flow was reduced from 167.1 +/- 27.2 in normal dogs to 146.2 +/- 17.1 cm3/min-100 g-1 in P hypertrophy, and was reduced further to 82.5 +/- 8.2 cm3/min-100 g-1 in V hypertrophy. Flows decreased similarly in epicardium and endocardium in both hypertrophied hearts. Cardiac O2 extraction in P and V hearts was greater than in control hearts. Myocardial O2 consumption was maintained at control values in P hypertrophy, and decreased by 54 +/- 3% in V hypertrophy. These findings indicate that LV function is impaired at rest in hypertrophy induced by V and is normal in hypertrophy induced by P.

Animals↗
PubMed1992

[Interdependence of preload, afterload and contractility: their relation to cardiac function curve].

Formerly, the major determinants of cardiac performance, i.e., preload, afterload contractility, and heart rate had been considered independent. This individual concept of these determinants was originally advocated by E.H. Sonnenblick in 1960's, providing an extremely useful tool in understanding basic cardiac mechanical physiology. We now know, however, that these determinants of cardiac performance are, in fact, interdependent with each other both at cellular and at ventricular levels. This concept of the interdependency of the determinants, in turn, is of practical importance during the conduct of clinical anesthesia. Since we cannot isolate one determinant from the other, we have to deal with them as they are. Furthermore, monitoring a parameter of one aspects of the patient's cardiac performance is not sufficient to understand or estimate patient's status. It is necessary to integrate these informations to make clinical decision under uncertain situations.

Heart↗
PubMed1976

Cardiac function in the treatment of arterial hypertension with propranolol.

1. Propranolol, when used for treating arterial hypertension, may influence determinants of both cardiac and vascular function; the consequent changes in cardiac performance may result from the interaction of different and possibly opposite effects. 2. Cardiac funtion was investigated in fifty-four primary hypertensive men in the pretreatment state and after 3 weeks of propranolol therapy at a daily dose of 320 mg. 3. beta-Receptor blockade caused depression of pre-injection left ventricular function, which was unrelated to the direction and the extent of changes in peripheral circulation. 4. The ejection left ventricular function could be either depressed or improved depending on the direction to which treatment shifted the vascular resistance, and consequently, the impedance to left ventricular ejection. 5. Withdrawal of the adrenergic support is probably the major factor responsible for the poor ventricular adaptation to an augmented impedance.

Cardiac Output↗
PubMed1992

Cardiac function and myocardial performance of 24-hour-preserved asphyxiated canine hearts.

A method of 24-hour storage of asphyxiated canine hearts for orthotopic cardiac transplantation was studied to expand the geographical size of the donor pool. Left ventricular function of asphyxiated hearts preserved for 24 hours (group 1, n = 8) was compared with that of hearts donated on-site (group 2, n = 5). Group 1 donors were pretreated with verapamil hydrochloride, propranolol hydrochloride, and prostacyclin. The donor hearts were perfused with warm blood cardioplegia in situ after 10 minutes of asphyxiation and then perfused with cold crystalloid cardioplegia for 2 hours. The hearts were excised and stored in ice-cold University of Wisconsin solution for 22 hours. At orthotopic transplantation, coronary perfusion with warm blood cardioplegia was performed before the graft aorta was unclamped. Conventional cardiac variables (eg, cardiac output and maximum rate of rise of left ventricular pressure), myocardial performance, and diastolic compliance of grafted hearts were assessed 1 hour after weaning from bypass. All recipients in both groups were easily weaned from cardiopulmonary bypass without inotropic agents, and there were no significant differences in cardiac variables between the two groups. These results strongly suggest that cadaver hearts can be preserved for 24 hours with satisfactory cardiac function.

Animals↗
PubMed1975

Is early decline of cardiac function in ischaemia due to carbon-dioxide retention?

There is no satisfactory explanation for the early and rapid decline of cardiac muscle function in ischaemia. Reduction of the energy source for contraction, A.T.P., is insufficient in magnitude and too slow in onset to be the prime cause. It is proposed that a large part of the loss of function is directly attributable to an immediate fall of intracellular pH and results from the accumulation of carbon dioxide and lactic acid; the intracellular acidosis reduces myocardial function by inhibition of that part of the calcium-ion influx associated with contraction.

Acidosis↗