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At least 685 records · Page 38Linked to original sources
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↗
PubMed2001

Effects of chronic food restriction and exercise training on the recovery of cardiac function following ischemia.

Clinical and experimental data suggest that exercise training (ET) and food restriction (FR) improve cardiovascular function. However, the effects of long-term FR or FR in combination with ET on the recovery of cardiac function following ischemia have not been determined. Male Wistar rats were assigned to ad libitum-fed, FR, ad libitum-exercise, and FR-exercise groups. Mechanical function of isolated working hearts was assessed in response to increases in afterload resistance and following global no-flow ischemia. At low workload, there was a significant FR effect on aortic flow as well as an interaction between FR and ET on systolic pressure. These effects remained when hearts were subjected to increases in aortic afterload resistance. During reperfusion of ischemic hearts, there was a significant FR effect on aortic flow and systolic pressure and a significant ET effect on diastolic pressure. An interaction between FR and ET on heart rate was also seen during reperfusion. In terms of percent recovery of heart function following ischemia, FR continued to affect aortic flow, and we observed an interaction between FR and ET on aortic flow. Our results clearly indicate that the myocardium from the FR animal or the FR, exercise-trained rat is more resistant to ischemia.

Animals↗
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↗
PubMed2003

Retrograde aortic isthmus net blood flow and human fetal cardiac function in placental insufficiency.

OBJECTIVE: Retrograde aortic isthmus (AoI) net blood flow has been associated with diminished oxygen delivery to cerebral circulation. This study was designed to characterize the cardiac function in human fetuses with retrograde AoI net blood flow in pregnancies complicated by placental insufficiency. METHODS: The control group comprised 43 fetuses in uncomplicated pregnancies. Study groups consisted of fetuses with placental insufficiency, and either antegrade (Group 1; n = 18) or retrograde (Group 2; n = 11) AoI net blood flow. Volume blood flows (Q) of left (LVCO) and right (RVCO) ventricles, ductus arteriosus (Q(DA)), pulmonary arterial bed (Q(P)) and foramen ovale (Q(FO)) were calculated and their proportions (%) of combined cardiac output (CCO) were determined. Ventricular ejection forces were calculated. Blood velocity waveforms of the mitral (MV) and tricuspid (TV) valves were obtained. The proportion of left ventricular isovolumetric relaxation time (IRT%) of the cardiac cycle, and index of myocardial performance (IMP) were calculated. RESULTS: In Group 1, Q(DA)% was increased (P < 0.05) and Q(P)% decreased (P < 0.05) compared with the control group, and Q(FO)% was greater (P < 0.01) compared with the control group and Group 2. In Group 2, the distribution of CCO did not differ from that of the control group. Ventricular ejection forces were similar among the groups. In Group 2, the MV early filling/atrial contraction time-velocity integral ratio was greater (P < 0.05) compared with those of the control group and Group 1. In Groups 1 and 2, IRT% and IMP were increased (P < 0.001) compared with the control group. CONCLUSIONS: In placental insufficiency, fetuses with antegrade AoI net blood flow show a shift in RVCO from the pulmonary to the systemic circulation, and Q(FO) makes up the majority of LVCO. Fetuses with retrograde AoI net blood flow fail to demonstrate these changes, suggesting a relative drop in the oxygen content of the blood entering the left ventricle.

Aorta, Thoracic↗
PubMed1983

[Monitoring of cardiac function during doxorubicin therapy in metastasized breast cancer. Measuring systolic time interval].

Assessment of systolic time interval represents an uncomplicated, sufficiently precise and cheap possibility in clinical practice of cardiac monitoring during treatment with doxorubicin (adriamycin) if the ratio between pre-ejection period interval (PEPI) and left ventricular ejection time interval (LVETI) ("Weissler index") for evaluation of left ventricular cardiac function is used. In an investigation of 352 female patients with metastatic carcinoma of the breast statistically ascertained dose-response relationships could be established as regards electrocardiographic disorders of repolarisation and the systolic time interval (P less than 0.001). Pre-irradiated patients showed more ECG changes (P less than 0.001) and higher PEPI : LVETI values (P less than 0.001) than patients without prior irradiation. There was no general influence of cytostatic treatment on systolic and diastolic blood pressure values. The upper limit of a therapeutic risk in evaluation of the systolic time interval for cardiac monitoring of doxorubicin treatment should be 0.45-0.50 for PEPI : LVETI. Above this borderline value precise cardiac evaluation including invasive methods should be attempted if continuation of treatment is indicated. This regime could help prevent the occurrence of life-threatening cardiac crises during treatment with doxorubicin.

Breast Neoplasms↗
PubMed2001

Effects of carnitine on cardiac function after cardioplegic ischemia in neonatal rabbit hearts.

BACKGROUND: Ischemia immediately impairs myocardial fatty acid metabolism and reduces the concentration of carnitine which is an essential cofactor for fatty acid metabolism in the mitochondria. The purpose of this study was to investigate the effects of carnitine administration on recovery of cardiac function after cardioplegic ischemia in the neonatal heart where fatty acid metabolism is not a predominant source of adenosine triphosphate. METHODS: Isolated blood-perfused neonatal rabbit hearts underwent 3 hours of cold cardioplegic ischemia. The control group (n = 10) was reperfused with unmodified diluted blood. The carnitine group (n = 10) was reperfused with the blood containing 5 mM/L of carnitine. Before ischemia (base line) and after 15 and 30 minutes reperfusion, left ventricular (LV) function and LV compliance were measured using a intraventricular conductance catheter combined with an isovolumic balloon. Coronary blood flow was measured and myocardial oxygen consumption was calculated. RESULTS: Carnitine significantly improved not only LV systolic function but also LV diastolic function (p < 0.05) as well as LV compliance after ischemia. Coronary blood flow and myocardial oxygen consumption were significantly improved after ischemia in the carnitine group compared with the control group (p < 0.05). CONCLUSIONS: These results suggest that carnitine strikingly improves LV functional recovery and aerobic metabolism after cold cardioplegic arrest, and may improve cardiac performance in neonates after open heart surgery.

Animals↗
PubMed2004

Viral-based myocardial gene therapy approaches to alter cardiac function.

In recent years there has been a rapid expansion in our understanding of the molecular biology that underpins human physiology. In the heart, elegant molecular pathways have been elucidated, and derangements in these pathways have been identified as factors in cardiac disease. However, as our understanding has grown, we have recognized that there exist only relatively crude tools to effect changes in molecular pathophysiology. The ultimate promise of gene therapy is to correct the molecular derangements that cause illness. To bring this promise to fruition in the clinical arena, many problems need to be solved, and chief among these remains reliable and robust delivery of genes to the target organ. To this end, viral vectors have been utilized with success more frequently than any other method of gene delivery. The use of these vectors in the heart has already offered promising novel benefit for human ischemic heart disease, and studies in animal models have given glimpses of hope that gene therapy may provide future therapeutic benefit in heart failure by improving cardiac function.

Animals↗
PubMed1978

A comparison of the effects of quinetholate, lidocaine and procainamide on ouabain-induced ventricular tachycardia and cardiac function.

The antiarrhythmic effects of the quinoline derivative, quinetholate, on ouabain-induced tachycardia were compared with those of lidocaine and procainamide in dogs. In addition, the effects of these three agents on cardiac function were compared. Quabain was injected intravenously until ventricular ectopic beats accounted for at least 60% of the heart rate. Then one of the above antiarrhythmic agents was infused until sinus rhythm was reestablished for a minimum of 3 min or until it became evident that successful reversion would not occur. All three agents effectively reversed ouabain-induced ventricular tachycardia in most instances. Quinetholate was especially consistent, causing 16 reversions out of a total of 17 experiments. The relative molar antiarrhythmic potencies of the three agents in responding animals were as follows: lidocaine = 1.0, procainamide = 1.5, and quinetholate = 3.1. Quinetholate caused the longest lasting reversions, i.e. usually lasting at least 30 min after infusion was stopped. The degree of cardiac depression caused by the three agents at their mean effective antiarrhythmic doses was determined using the left ventricular function curve method. Lidocaine produced a significant depression of the ventricular function curve at the antiarrhythmic dose while procainamide and quinetholate did not.

Aminoquinolines↗
PubMed1978

Dobutamine in the treatment of depressed cardiac function: a study in patients with ischaemic heart disease during the early post-operative period.

Dobutamine was administered by intravenous infusion to 10 patients with ischaemic heart disease who had a low cardiac output syndrome following abdominal surgery. The dosage of dobutamine started from 2.5 mcg kg-1 min-1 and was increased stepwise to 5, 7.5, 10, 12.5 and 15 mcg kg-1 min-1. Cardiac index increased significantly from 2.05 +/- 0.32 to 3.03 +/- 0.61. min-1 min-2 with 15 mcg kg-1 min-1. Heart rate was unchanged with 7.5 mcg kg-1 min-1 but increased significantly from 97.7 +/- 18.5 to 126.1 +/- 21.5 beats. min-1 with 15 mcg kg-1. min-1. Stroke index increased significantly from 21 +/- 4.4 to 25.4 +/- 5.1 ml m-2. beat-1 with 7.5 mcg kg-1 min-1. Pulmonary wedge pressure fell significantly from 14 +/- 2.9 to 9.1 +/- 2.4 mmHg with 2.5 mcg kg-1 min-1. Mean arterial pressure showed no significant change. No side effects were observed in these patients. We conclude that in patients with depressed cardiac function dobutamine at low doses of 2.5 mcg kg-1 min-1 decreases afterload and filling pressures. At the average doses of 5 - 7.5 mcg kg-1 min-1 stroke index and cardiac index are increased. At higher doses of 10 - 15 mcg kg-1 min-1 heart rate and cardiac index increase while stroke index fails to increase further.

Aged↗
PubMed2001

Effect of diltiazem on cardiac function assessed by echocardiography and neurohumoral factors after reperfused myocardial infarction without congestive heart failure.

The purpose of this study was to examine the effect of diltiazem on cardiac function and neurohumoral factors (BNP, epinephrine, norepinephrine) after reperfused myocardial infarction without congestive heart failure (Killip class I). On the first day after myocardial infarction following reperfusion therapy patients were randomly assigned to diltiazem treatment (group 1, n=33) or no treatment (group 2, n=39). We then performed echocardiographic examinations on the patients and measured heart rate, mean blood pressure and neurohormones (BNP, epinephrine and norepinephrine). Follow-up evaluations of echocardiography were performed at 4 and 12 weeks and of neurohormones at 1 and 4 weeks after acute myocardial infarction. The highest peaks of plasma BNP, epinephrine, and norepinephrine levels were observed before treatment and decreased with time in both groups. After 4 weeks the level of plasma BNP in the diltiazem treatment group was lower than in the no treatment group [55+/-3 pg/mL vs 85+/-5 pg/mL (P < 0.05)]. Other neurohormones did not differ between groups. Fractional shortening (FS) and ejection fraction (EF)improved after myocardial infarction in both groups, but significantly more in the diltiazem group (P < 0.05) after 12 weeks of treatment. Changes in BNP correlated significantly with changes in left ventricular end systolic volumes, FS and EF. In this study, diltiazem significantly improved systolic function and reduced the level of plasma BNP after myocardial infarction, which suggest that diltiazem may have a beneficial effect on myocardial infarction without congestive heart failure.

Aged↗
PubMed1993

Influence of the hydrostatic intraperitoneal pressure and the cardiac function on the lymphatic absorption rate of the peritoneal cavity in CAPD.

The purpose of this study was to determine the influence of hydrostatic intraperitoneal pressure (IPP) and cardiac function (CF) on the lymphatic absorption rate (LAR) in 9 patients on continuous ambulatory peritoneal dialysis (CAPD). The LAR was measured by estimation of the intraperitoneal disappearance of dextran 70 added to 2 L of 2.5% dextrose dialysis solution. The patients remained in the supine position during the 4-hour dwell. The IPP was obtained by measuring a column of dialysate in the peritoneal dialysis line, immediately before the drainage of the peritoneal cavity. The pressure was measured at the level of the umbilical cicatrix with point zero located on the mid axillary line of the patient. IPP was measured at inspiration and expiration, and the average of these two measurements was taken. These patients also underwent an echocardiographic examination. The LAR was 0.46 +/- 0.25 mL/minute, and the IPP was 13.07 +/- 2.61 cm H2O. The IPP correlated positively with the LAR (r = 0.80, p < 0.05). The intraperitoneal volume at the 4-hour dwell correlated inversely with the IPP (r = -0.68, p < 0.05). The left ventricular circumferential shortened fraction was 36 +/- 6% (27%-43%) and did not correlate with the LAR. These data suggest that the LAR is higher in patients with more elevated IPP. In addition, the CF, in the range studied, does not affect the lymphatic absorption rate.

Absorption↗
PubMed1995

[Alterations of cardiac function and metabolism in the rat heart-lung preparation by methyl methacrylate (MMA) and their protection by ulinastatin].

We have assessed the deleterious effects of methyl methacrylate (MMA) on cardiac function and metabolism in the isolated heart-lung preparation and their protection by ulinastatin. Twenty-four male Wistar rats were prepared for the heart-lung model. They were randomly divided into 3 groups. In the MMA (M) and ulinastatin (U) groups, MMA 1000 micrograms.ml-1 was administered 7 minutes after the start of perfusion. At the end of the experimental period, the hearts were freeze-clamped and then myocardial high energy phosphates, lactate and glycogen were measured. Cardiac output decreased significantly in the M and U groups. Po2 of the perfusion blood in the M and U groups was significantly lower than that in the control (C) group. Myocardial ATP in the M and U groups was significantly lower than that in the C group. ADP and AMP in the M and U groups were higher than those in the C group. Although there was no significant difference in lactate levels among the 3 groups, glycogen in the U and C groups was significantly higher than that in the M group. MMA 1000 micrograms.ml-1 is much higher than the blood level (0.05-31.89 micrograms.ml-1) reported clinically in patients who had femoral prosthesis. Ulinastatin increased myocardial glycogen content which had been reduced by MMA. This may suggest that ulinastatin has a protective effect on heart damaged by MMA.

Adenosine Diphosphate↗
PubMed1999

The cardiac renin-angiotensin system: conceptual, or a regulator of cardiac function?

Angiotensin II, the effector peptide of the renin-angiotensin system, regulates cellular growth in response to developmental, physiological, and pathological processes. The identification of renin-angiotensin system components and angiotensin II receptors in cardiac tissue suggests the existence of an autocrine/paracrine system that has effects independent of angiotensin II derived from the circulatory system. To be functional, a local renin-angiotensin system should produce sufficient amounts of the autocrine and/or paracrine factor to elicit biological responses, contain the final effector (angiotensin II receptor), and respond to humoral, neural, and/or mechanical stimuli. In this review, we discuss evidence for a functional cardiac renin-angiotensin system.

Angiotensin II↗
PubMed2001

Does the laparoscopic approach significantly affect cardiac functions in laparoscopic surgery? Pilot study in non-obese and morbidly obese patients.

BACKGROUND: Laparoscopy in bariatric surgery represents a modern method generally associated with lower morbidity and mortality, compared with the traditional surgical approach. However, in patients with impaired cardiovascular function, the laparoscopic approach is limited by the potential adverse hemodynamic impact. We assessed the influence of some laparoscopic procedures on selected cardiac functions in significantly obese patients and in subjects with normal body weight, using transesophageal echocardiography (TEE). PATIENTS AND METHODS: Six subjects with normal body weight (mean BMI 25.3 +/- 3.6 kg/m2), and six patients undergoing laparoscopic gastric banding for morbid obesity (mean BMI 45.8 +/- 7.5 kg/m2) were studied. Heart rate (HR), blood pressure (BP), ejection fraction, cardiac output (CO) and transmitral flow were measured. Parameters were recorded at baseline before the operation (BL), after installation of capnoperitoneum (CP), and after positioning the patient for surgery (SP). RESULTS: Compared to BL, CP and SP were characterized by an increase in HR and BP in both groups of patients. As ejection fraction did not change significantly, the HR changes were accompanied by an increase in CO: (BL 5.8 +/- 2.2 l/min, CP 6.5 +/- 2.6 l/min, SP 6.7 +/- 2.7 l/min, p < 0.05 BL vs CP and SP). Transmitral flow parameters did not change significantly. Hemodynamic changes in subgroups with normal body build and in the obese patients were comparable. There was an increase in CO and pressure-rate product in obese individuals. CONCLUSIONS: Our results suggest that the hemodynamic response to laparoscopic surgery is characterized by an increase in CO (due to increased HR) and BP. In subjects without a manifest cardiovascular disease, neither systolic nor diastolic performance was significantly affected by the introduction of capnoperitoneum and positioning of the patient for surgery. Similar results were observed in obese and non-obese subjects. Phase II of this on-going study is focusing on impact and safety of laparoscopy in obese patients with known cardiovascular disease.

Adult↗
PubMed1975

Evaluation of cardiac function and venous return curves in awake, unanesthetized cialves with an implanted total artificial heart.

1) The implanted TAH offers a method of evaluating the effects of varying physiologic demands cardiac output and venous return. 2) Cardiac output and venous return measurements offer a method of evaluating system design of the device and driving and control-logic improvements in awake, unanesthetized animals. 3) The obtained cardiac function and venous return curves suggest that the present TAH is less responsive to increases in right atrial pressure than the natural heart, but is still completely controlled by venous return. Therefore, it is extremely important to make every effort to eliminate any factor causing excessive venous return.

Animals↗