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At least 109 records · Page 6Linked to original sources
PubMed1992

Acute improvement of cardiac function with intravenous L-propionylcarnitine in humans.

As the myocardial carnitine content, a key control factor in myocardial oxidative metabolism and energy transfer, is reduced in heart failure, administration of L-propionylcarnitine (LPC), a potent analogue of L-carnitine, potentially may improve cardiac function, possibly through a positive inotropic effect. As its hemodynamic profile is unknown in humans, 32 fasting normotensive patients with coronary artery disease received either 15 mg/kg of LPC (n = 16) or vehicle (mannitol/acetate, n = 16) infused over 5 min. Hemodynamic, radionuclide [peak ejection and filling rates (PER and PFR, respectively)], and metabolic variables (myocardial O2, lactate, and carnitine uptake) were studied at baseline and 1, 3, 5, 10, 15, and 45 min postdrug. The baseline ejection fraction was depressed in LPC patients (40 +/- 3% vs. 48 +/- 4% in the vehicle group, p less than 0.05) as a result of a significant high incidence of previous infarctions. Immediately following LPC, the cardiac total carnitine uptake changed from 102 +/- 181 to 5,335 +/- 1,761 mumol/L (p less than 0.05). In both groups, left ventricular systolic and end-diastolic pressures increased significantly by 5 and 20%, respectively, during the first 5 min. In the vehicle group, contractility decreased by 5%, accompanied by a significant 11% fall in the stroke volume. In contrast, following LPC, isovolumetric contractility indices remained unaltered. Instead, both the PER and PFR improved by 16% at 45 min. Moreover, the cardiac output increased by 8%. LPC did not affect systemic or coronary hemodynamics. Lactate uptake increased by 42%, but myocardial O2 consumption did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1976

Acute cardiac failure: the relation between coronary flow and cardiac function.

To study the effects of acute coronary hypotension on the working dog heart in situ, both coronary arteries were cannulated and perfused with oxygenated blood at controlled pressures (40 to 120 mm Hg). At a perfusion pressure of 120 mm Hg, total coronary artery flow appeared to be sufficient (0.95+/-0.08 ml/min-g) to maintain normal cardiac performance for a 2.5-hour observation period. During incremental decreases in coronary perfusion pressure, significant linear correlations were found between coronary flow and cardiac index (r=0.84), left ventricular maximum dP/dt (r=0.83), stroke index (r=0.82), stroke work (r=0.83) and mean arterial pressure (r=0.62). During simulated shock conditions (systolic arterial pressure, less than 75 mm Hg), relative reductions in coronary flow (-60.9+/-4.0%) paralleled changes seen in cardiac function and persisted for 28+/-4 min.

Animals↗
PubMed1975

Effects of metrizamide, a new nonionic contrast medium, on cardiac function during coronary angiography in the dog.

Metrizamide is a new non-ionic radiopaque agent with low osmolarity and low intravenous toxicity. Hyperosmolarity is one of the factors involved in the decrease of myocardial contracility, alterations of aortic pressure, and disturbances in the cardiac rhythm which contrast media induce during coronary angiography. Metrizamide has been compared to other commonly used contrast media and was shown to produce fewer changes on the cardiac functions recorded.

Aminoglycosides↗
PubMed1991

[Quantitative study of myocardial pathological lesions in rheumatic mitral valve disease: correlations with changes in cardiac function after valve replacement].

Pathological lesions of left ventricular myocardium from 21 patients with predominant mitral stenosis (MS) and from 16 patients with predominant mitral regurgitation (MI) were studied quantitatively by means of image analysis system and light microscopic examination. Their correlations with changes of cardiac function after mitral valve replacement were also studied. The results showed that the percentage of the area of interstitial fibrosis (F%), the shortest diameter of myocardial fiber (SDMF) and endocardial thickness (ET) increased, and the inner diameter-out diameter ratio of intramyocardial arteries (Di/Do) decreased in 37 patients in various degrees. F%, Di/Do, SDMF and ET correlated with delta EF, delta FS, delta ESVI, postoperative dosage of dopamine, and duration of assisted respiration analysed respectively by linear regression. Multiple myocardial pathological lesions correlated strongly with delta EF analysed by multiple linear regression with multiple correlation coefficient of 0.803 in MS group (P less than 0.01) and 0.763 in MI group (P less than 0.05). These data suggest that multiple evaluation of myocardial pathological lesions plays an important role in predicting prognosis of mitral valve replacement. After operation mean delta EF and delta FS decreased, dosage of dopamine and duration of assisted respiration increased when the patient had two or more following criteria: 1. F% greater than 31%, 2. Di/Do less than 0.400, 3. SDMF greater than 16 microns, 4. ET greater than 326 microns.

Adolescent↗
PubMed1975

Cardiac function during halothane anf fluroxene anesthesia expressed by systolic time intervals.

A non-invasive method of measuring the systolic time intervals (STI) during anesthesia is described. Using the ratio between the pre-ejection period and the left ventricular ejection time (PEP/LVET-ratio) as an expression of cardiac function, it is shown in 39 patients that thiopentone exerted a marked depression on the heart (increase in PEP/LVET-ratio). This depression was further aggravated by halothane, while fluroxene caused an improvement of PEP/LVET-ratio. In the immediate post-anesthetic period PEP/LVET-ratio almost reached control value after discontinuation of fluroxene in contrast to halothane, where an increased PEP/LVET-ratio (25%) still persisted. The changes were mainly due to a prolongation of PEP without any specific change in LVET. During the study, PEP/LVET-ratio showed a close correlation to the reciprocal value of the square of the pre-ejection period (1/PEP-2). STI form 27 volunteers were measured and compared to the values from the patients before anesthesia was induced. PEP and PEP/LVET-ratio were significantly shorter in the patient group.

Adolescent↗
PubMed1975

Value of ventriculography in cardiac function and diagnosis.

The methods for calculating left ventricular volumes employing biplane angiocardiograms and the calculated parameters of left ventricular mass, pressure-volume diagrams, wall forces, compliance, and abnormally contracting segments are described. Examples of these calculations are given and the contributions to the assessment of cardiac function and diagnosis are discussed. Normal values and the alterations produced by volume overload, pressure overload, myocardial disease, and coronary artery disease are presented.

Angiocardiography↗
PubMed1976

Effect of methyldopa treatment on cardiac function and myocardial blood flow in mongrel dogs.

Administration of methyldopa (100 mg/kg, orally twice daily for a period of 3 days) to mongrel dogs produced significant reductions in blood pressure and heart rate. The hypotensive effect of the drug was due to a reduction in peripheral resistance. Methyldopa treatment also produced a significant decrease in coronary vascular resistance. Studies on the left ventricular function indicated that treatment with methyldopa does not compromise the ability of the myocardium to respond to an increased work load. Thus, the beneficial effect of this agent on the myocardial circulation, together with its lack of any detrimental effect on the cardiac function suggest that methyldopa may be an effective agent for the control of hypertension.

Animals↗
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↗