The purposes of the study were (1) to characterize left ventricular wall motion, and the cardiodynamic and metabolic responses during electrical stimulation cycle ergometry (ESCE) exercise in tetraplegic people; (2) to test whether these responses linger into the post-exercise recovery period; and (3) to test whether they differ from those ...

This study was carried out to test the hypothesis that alpha 1-adrenergic activation during exercise causes preferential vasoconstriction of subepicardial coronary resistance vessels, thereby augmenting blood flow to the subendocardium. Studies were performed in 7 dogs in which left ventricular hypertrophy was produced by banding the ascending aorta at 6-9 ...

Recombinant human erythropoietin (r-HuEPO) treatment reduces cardiac output and increases left ventricular mass: beneficial effects that might be expected to be maximized at near-normal haemoglobin values. Quality of life in dialysis patients treated with r-HuEPO has been shown to be related to haemoglobin, up to a haematocrit of 35%. The ...

The aim of this work was to compare left ventricular performance during weight reduction induced by either physical training and diet or diet alone. Forty-three moderately obese subjects received a hypocaloric diet of 800 kcal/d for 4 weeks; 22 of them were also subjected to an exercise program. By means ...

The aim of our study was to evaluate cardiovascular function at rest and during exercise in dialysis patients before and after treatment with Epo and to examine the changes in left ventricular mass as the consequence of treatment for anaemia. We applied echocardiography and radionuclide ventriculography at rest and after ...

PURPOSE: To determine the type and prevalence of prenatal ultrasound (US) findings in fetuses with trisomy 13. MATERIALS AND METHODS: Prenatal US findings in 33 consecutive fetuses with trisomy 13 and in 200 karyotypically normal fetuses were reviewed and compared. RESULTS: One or more abnormalities were found in 30 fetuses ...

The aim of the study was to examine the effect of chronic angiotensin converting enzyme inhibition on haemodynamics and left ventricular performance during long-lasting exercise at the anaerobic threshold. For this purpose exercise haemodynamics and left ventricular performance were assessed in 14 physically trained hypertensives (aged 26 y) before and ...

The cardiac functional response to exercise in patients with nonobstructive hypertrophic cardiomyopathy (HCM) was evaluated using a continuous ventricular function monitor with a cadmium telluride detector (CdTe-VEST). METHODS: Supine ergometric exercise was performed under CdTe-VEST monitoring in 41 patients with nonobstructive HCM (34 men and 7 women, age 18-72 yr, ...

Transient dilatation of the left ventricular cavity on exercise thallium perfusion imaging is recognized as a marker of significant coronary disease, but the mechanisms that produce this finding are not fully understood. We studied 32 patients who underwent exercise thallium imaging and exercise echocardiography to determine the changes in left ...

BACKGROUND: Peak oxygen consumption is reduced in patients with symptomatic congestive heart failure, but functional capacity of patients with asymptomatic left ventricular systolic dysfunction has not been assessed by measurement of peak oxygen consumption attained during graded exercise testing. METHODS AND RESULTS: Peak oxygen consumption, that is, aerobic capacity (VO2, ...

Medical management of patients with chronic left ventricular dysfunction continues to be a difficult problem. Recent clinical and experimental studies have suggested that 3,5,3'-triiodo-L-thyronine improves left ventricular pump function. However, whether 3,5,3'-triiodo-L-thyronine directly improves myocyte contractile function in cardiomyopathic states is unknown. Accordingly, this study examined the direct effects of ...

Left ventricular function was examined during incremental work rates to maximum using simultaneous determinations of stroke volume, left ventricular ejection time (LVET), and diastolic filling time (DT). Seven endurance trained and seven untrained young adult males were studied on a cycle ergometer at matched heart rates of 90, 120, 140, ...

alpha-Adrenergic receptor responsiveness has been reported to increase during myocardial ischemia, correlating with onset of malignant arrhythmias. If alpha-adrenoceptor mechanisms play a significant role in induction of life-threatening arrhythmias, inhibition of these receptors with specific alpha-adrenoceptor antagonists should protect against disturbances in cardiac rhythm. To test this hypothesis, we induced ...

Evaluation of eye-hand coordination skills in relation to experiential human factors may lead to improved instruction for videoendoscopic surgical skills acquisition. Twenty-nine subjects (medical students or residents in surgical specialties) volunteered to perform three exercises of increasing complexity in an "inanimate" trainer system that simulated the eye-hand coordination tasks inherent ...

OBJECTIVES: This study was undertaken to determine whether abnormalities in exercise capacity or ventricular function persist after recovery from acute dilated cardiomyopathy. BACKGROUND: Persistent ventricular structural abnormalities could cause abnormalities in exercise capacity or ventricular function. METHODS: The results of rest and exercise first-pass radionuclide ventriculography in 18 patients who ...

In healthy normotensive individuals who have been rigorously screened to exclude coronary disease, the cardiovascular reserve capacity decreases with aging. A reduction in the maximum aerobic capacity is accompanied by a reduction in the maximum heart rate. Stroke volume during vigorous exercise in the upright position does not decline with ...

Physiologic variables, such as heart rate, affect the noninvasive indexes of left ventricular filling, complicating the interpretation of these indexes for clinical assessment of diastolic function. We compared the effect in normal subjects of increased heart rate provoked by both exercise and amyl nitrite on noninvasive velocity and volumetric indexes ...

OBJECTIVES: The purposes of this study were to evaluate left ventricular performance and contractility at rest and during exercise to determine mechanisms and correlates for alterations in performance and blood pressure in pediatric patients after successful repair of coarctation of the aorta. BACKGROUND: Blood pressure and left ventricular function are ...

Endurance exercise requires that the heart maintain a highly elevated cardiac output for an extended period of time, working against a slightly elevated afterload. Endurance athletes manifest a large ventricular volume, characterized on echocardiogram by an increased end-diastolic internal diameter and wall thickness. This article describes the structural, functional, and ...

Five cases of exercise induced pure vasodepressor syncope in patients without significant structural heart disease are reported. Hypotension and symptoms of syncope or pre-syncope were induced by treadmill exercise testing and in each case limited exercise performance. Evidence of inappropriate peripheral vasodilation, probably as a consequence of ventricular mechanoreceptor stimulation, ...

The hemodynamic factors contributing to reduced exercise capacity in adults with congenital heart disease are not fully defined. We hypothesized that they would demonstrate reduced exercise capacity compared with age-matched control subjects because of abnormal exercise hemodynamics and ventricular performance demonstrable by echocardiography. We retrospectively analyzed the results of all ...

This review describes age-related changes in autonomic control of the circulation during exercise and the associated effects on exercise capacity. The increase in heart rate during exercise becomes smaller with aging probably due to both less withdrawal of cardiac vagal tone and diminished beta-adrenergic responsiveness. The latter also appears to ...

OBJECTIVES: To investigate whether cardiovascular performance can be modified beneficially with left ventricular hypertrophy reversal and whether the associated sudden afterload increases may adversely affect overall cardiac performance. METHODS: We studied cardiovascular performance with thermodilution techniques at rest and during maximal treadmill exercise after 3 weeks' treatment with the angiotensin ...

Hemodynamic parameters during supine leg exercise-induced myocardial ischemia were investigated in ten patients without left ventricular hypertrophy (group I), and in ten patients with left ventricular hypertrophy (group II). Both groups of patients had previously been diagnosed as having totally asymptomatic silent myocardial ischemia. Both groups were comparable in age, ...

To compare hemodynamic changes induced by isoproterenol and exercise stress tests in individuals with and without left ventricular volume load, we studied 10 lambs with an aortopulmonary shunt [58 +/- 4% (SE) of left ventricular output] 2 wk after the shunt was created. Two studies, isoproterenol infusion at 0.1 microgram.kg-1.min-1 ...

Acute postoperative left ventricular dysfunction after hypothermic, crystalloid potassium cardioplegia occasionally occurs. This project examined myocyte contractility and inotropic responsiveness after hypothermic arrest with and without potassium cardioplegia. Isolated swine left ventricular myocytes were placed in a thermostatically controlled chamber (37 degrees C) that contained a standard cell medium, pulse ...

BACKGROUND: The effects of chronic exercise training on myocardial contractility and beta-adrenergic signal transduction in hearts with left ventricular dysfunction have not been determined. METHODS AND RESULTS: Fourteen-week-old cardiomyopathic BIO 53.58 and normal F1B Syrian hamsters underwent 10 weeks of treadmill training and were compared with 24-week-old BIO 53.58 and ...

Three patients (age 18-39 years; two men) with normal exercise capacity, normal left ventricular function, large muscular false tendons within the left ventricle, and anomalously placed papillary muscles associated with giant T wave inversion on the electrocardiogram are described. The absence of adverse cardiovascular events at long-term follow up (mean ...

Left ventricular function during exercise and recovery was investigated in patients with angina pectoris, ST segment depression during exercise and angiographically normal coronary arteries (syndrome X) using a continuous left ventricular function monitor with cadmium telluride detector (CdTe-VEST). Fourteen patients with syndrome X and 14 patients with atypical chest pain ...

OBJECTIVE: To investigate the possible association between Doppler left ventricular filling pattern and exercise capacity in a group of normotensives to severe hypertensive patients. BACKGROUND: Invasive left ventricular filling indexes evaluated at rest are reported to be related to exercise capacity in heart failure. Whether exercise capacity is limited by ...

Patients with acute or chronic heart disease may have limited exercise capacity if they have reduced left ventricular function. Indexes of reduced left ventricular function during exercise are a predictor of subsequent survival although left ventricular ejection fraction is a poor predictor of physical endurance. We evaluated the effect of ...

The exercise hemodynamics of eight patients who underwent cardiac catheterization were assessed at rest and during exercise, before and after left ventricular aneurysmectomy by the classical technique. Left ventricular end-diastolic volume increased before operation and then significantly decreased after the operation (p < 0.05). The ejection fraction increased from 0.27 ...

Ventricular fibrillation (VF) is a major cause of sudden cardiac death in humans. Currently used antiarrhythmic drugs are aimed at preventing initiation of VF by decreasing the incidence of arrhythmias which can lead to VF. This approach today seems to be insufficient. On the basis of reports that VF can ...

To evaluate the effects of gender and isometric handgrip exercise on left ventricular diastolic function in normal individuals, atrial and rapid filling fraction were investigated using M-mode echocardiography in 35 postmenopausal women and 31 age-matched men. There were no significant differences in heart rate, mean blood pressure, atrial filling fraction, ...

OBJECTIVES: The goal of this study was to assess patients with end-stage heart disease after implantation of a left ventricular assist device at rest and during exercise compatible with activities of daily life. BACKGROUND: Mechanical circulatory assistance with a left ventricular assist device is an accepted therapy for bridging patients ...

The role of myocardial revascularization in the treatment of malignant ventricular arrhythmias is not well defined. Our hypothesis was that in patients with ventricular tachycardia or fibrillation exposed by exercise-induced ischaemia, the acute transient ischaemia plays a principal causal role, and that in these patients surgical myocardial revascularization alone might ...

This study prospectively assessed the time course, magnitude and mechanism of the hemodynamic changes after restoration of sinus rhythm in patients with chronic atrial fibrillation (AF) unassociated with valvular disease. Severe cardiac dysfunction may occur after chronic supraventricular tachycardia in patients with and without underlying cardiac disease. Improvement may follow ...

OBJECTIVES: The aim of this study was to identify dynamic predictors of exercise duration in patients with systolic left ventricular dysfunction and to test the hypothesis that left ventricular shape is an independent determinant of exercise duration in these patients. BACKGROUND: Measurements of left ventricular volumes and ejection fraction at ...

The initiating mechanisms of exercise-induced ventricular tachycardia were studied in a population of 5842 patients who performed 9064 bicycle exercise tests. Sixty (1%) patients had 194 episodes of ventricular tachycardia during the test. Forty-two percent of these occurred during exercise and 58% during recovery. Two different initiating electrocardiographic patterns were ...

This study examined the effects of anabolic steroids and exhaustive endurance exercise, and the combination of both treatments on in vitro cardiac contractile function. Fifty-two male Sprague-Dawley rats were randomly assigned, in groups of 13, to one of the four groups: sedentary control (C), steroid-treated (ST), exercise-trained (E), and exercise ...

Global and regional atrial blood flow was measured with radioisotope-labeled microspheres in eight dogs during rest and two levels of exercise. Both mean right and left atrial blood flow increased significantly (P < 0.05) to a similar degree with each level of exercise (right atria: 0.27 +/- 0.04, 0.89 +/- ...

Only limited information is available concerning left ventricular (LV) response to exercise after an external conduit operation for cyanotic congenital heart disease. Sixteen patients who had undergone external conduit repair (EC group) were studied with multi-gated cardiac pool imaging using a supine bicycle ergometer on 20 occasions. Six patients with ...

BACKGROUND: Controversy exists about the clinical and prognostic significance of exercise-induced ventricular arrhythmias late after myocardial infarction. The aim of the study was to identify the main clinical and prognostic features of exercise-induced ventricular arrhythmias in out-patients with healed Q-wave myocardial infarction. METHODS: The study population was 777 consecutive patients ...

Primary diastolic dysfunction or failure is a distinct pathophysiologic entity. It results from increased resistance to ventricular filling, which leads to an inappropriate upward shift of the diastolic pressure-volume relation, particularly during exercise (exercise intolerance). The causes of diastolic failure are inappropriate tachycardia, decreased diastolic compliance and impaired systolic relaxation. ...

Orthotopic heart transplantation results in altered atrial anatomy and denervation of the donor heart. To assess the impact of these sequelae on left ventricular filling and systolic performance, 16 heart transplant recipients and 10 normal controls were evaluated by Doppler echocardiography at rest and during graded bicycle exercise. Global and ...

Magnetic resonance imaging (MRI) provides high-resolution images of the heart. However, physical exercise during MRI is difficult due to space restriction and motion artefacts. To evaluate the feasibility of MRI during stress conditions, dobutamine was used as an alternative to exercise. Haemodynamics, ventricular volumes and wall thickening were measured at ...

Concentric left ventricular hypertrophy (LVH) frequently occurs in subjects with normal resting systolic and diastolic pressures (SP and DP, respectively). LVH in this normotensive-hypertrophic group (NH) may be due to an abnormally exaggerated pressure response to exercise. The SP and DP responses to exercise were studied in 130 subjects free ...

Digitalis intoxication is one of the most common adverse drug reactions. Although some arrhythmias are seen more frequently than others, virtually any rhythm disturbance, including ventricular tachycardia, may occur. However, to our knowledge, exercise-induced ventricular tachycardia as a complication of digitalis therapy has never been described before. This case presents ...

We studied 14 patients who had exercise-induced ventricular arrhythmias after a previous Q-wave myocardial infarction. All had symptomatic mild heart failure in New York Heart Association class II and a maximal oxygen consumption between 16 and 20 ml/kg/min. They were treated with the angiotensin converting enzyme inhibitor benazepril (20 mg) ...

We studied the correlation between changes in left ventricular filling dynamics induced by acute intravenous administration of verapamil and the changes in exercise tolerance induced by oral administration of the agent in 30 patients with hypertrophic cardiomyopathy. Diastolic cardiac function was measured by means of a nuclear stethoscope before and ...