Systolic time intervals (STI) obtained during exercise are useful as a method of estimating global left ventricular function. The conventional method, however, which requires a carotid pulse tracing as well as a phonocardiogram of high quality, is technically difficult under conditions of exercise. We have validated a new method of ...

Blood flows to major organs were measured in conscious cats to study the changes in the distribution of cardiac output during voluntary static (isometric) exercise. Five animals were operantly conditioned to hold a bar against a fixed resistance for 30 s. Organ flows were measured during rest and exercise by ...

The ability of patients with severely impaired left ventricle function to perform short-term exercise and to participate in a cardiac rehabilitation program and attain physical training effects was evaluated. Treadmill exercise tests were performed before and after physical conditioning in 10 patients with a prior myocardial infarction and a left ...

Repeated maximum exercise testing with an intertest interval of one hour is a valid model for testing drug efficacy and safety on ventricular arrhythmias occurring during exercise. In the two consecutive exercise tests the mean total number of VES was 182 and 184 respectively and the slope of the regression ...

Exercise tests were done on all patients referred to us because of ventricular premature beats. Exercise-associated ventricular tachycardia was seen in three of these patients. Once therapy for the arrhythmia was begun in two patients, we performed serial exercise tests, attempting to provoke the arrhythmia again. In the third patients, ...

We evaluated the effects of isosorbide dinitrate on some of the major determinants of myocardial oxygen demand during upright exercise in ten normal subjects. In addition to heart rate and systolic blood pressure, we assessed left ventricular size and performance by echocardiography. Compared to the control study, heart rate was ...

The occurrence of ventricular arrhythmias was studied in 25 healthy young men, with the aid of ambulatory ECG monitoring, during maximal bicycle tests, short term running, exhausting route marches, and during a 16 h period after brief and long term exercise. The bicycle test allowed prediction of 4 out of ...

The reported investigations were carried out in 50 healthy young men. Twenty of them (group I) performed a three-grade exercise on a Zimmermann cycle ergometer after smoking 4 "Sport" cigarettes, while another 30 subjects served as controls (group II). The exercise was carried out at 60 r.p.m. at a power ...

Electrophysiologic study, isoproterenol infusion, and serial treadmill exercise tests before and after administration of propranolol, verapamil, lidocaine, and procainamide were done in three patients with exercise-triggered ventricular tachycardia. In all three patients, organic heart diseases were absent. Ventricular tachycardia was reproducibly provoked with exercise and with isoproterenol infusion. Propranolol (tested ...

Chronic volume overload and subsequent left ventricular hypertrophy (LVH) were produced by a surgical shunt between the left subclavian artery and the left atrial appendage in eight dogs. A sham operation was performed on six control dogs. Analysis of biplane ventriculograms showed no significant differences in ejection fraction, mean wall ...

We studied nine freshmen and 14 senior oarsmen undergraduates during seven months of training and compared them with 17 age and sex-matched sedentary control subjects in order to assess the influence of heavy physical exercise on cardiac dimensions and maximal oxygen uptake. Standard M-mode echocardiographic techniques were used. At the ...

This study was designed to characterize the changes in left ventricular performance induced by graded isometric exercise. Fourteen healthy subjects (12 men and 2 women), aged 19 to 27, performed handgrip isometric exercise at 20, 40, and 60 percent of their maximal voluntary contraction (MVC) with three minutes of rest ...

Ambulatory electrocardiography and exercise testing are two noninvasive diagnostic procedures widely employed to evaluate patients for cardiac arrhythmias and S-T segment changes. This review addresses the differences and similarities of the two techniques, and examines the relative diagnostic and prognostic merit of the arrhythmia and S-T segment changes detected with ...

To determine the acute and chronic effects of static and dynamic exercise upon the cardiovascular system, two groups of athletes were studied and compared to untrained control individuals. Thus, 12 long distance runners (LDR) and 17 competitive weight lifters (CWL) were compared to 10 light controls (LC) and 14 heavy ...

To determine whether exercise training results in increased left ventricular mass in patients with ischemic heart disease, we obtained echocardiograms in 14 coronary patients before and after an average of seven months (range 3 to 14 months) of supervised arm and leg exercise. Each echocardiogram was interpreted jointly by two ...

The effect of Alinidine (ST 567) on hemodynamics at rest and during exercise was studied in subjects with angiographically documented coronary artery disease and left ventricular dysfunction. Exercise tests were performed before and 30 min after intravenous administration of 20 mg of Alinidine. Significant decreases were observed for heart rate ...

To determine the effects of exercise training on left ventricular performance and myocardial perfusion in coronary artery disease, rest and exercise radionuclide angiocardiography and thallium-201 scintigraphy were performed before and after 12 weeks of training in 16 coronary patients. After training, 15 of the 16 patients had improved exercise tolerance; ...

The effects of coronary bypass grafting on ventricular tachycardia induced by treadmill stress testing (TST) were analyzed in nine patients by repeating the test an average of 5 months after operation. Preoperatively, eight patients experienced pain and all had ischemic ST-segment depression during exercise. Six patients had a single episode ...

A quantitative two dimensional echocardiographic study was conducted in 10 normal subjects performing bicycle exercise in a supine position. Standardized two dimensional echocardiographic short axis and apical views of the left ventricle were analyzed to derive left ventricular sectional areas and length. Over a range of exercise heart rates from ...

The ventricular effective refractory period is commonly employed as a measurement of ventricular excitability. Because the current strength used to make this determination varies among laboratories, the relation of refractoriness and current was examined over a range of current strengths from 0.1 to 10 mA. Sixty determinations of refractoriness at ...

In order to estimate the value of haemodynamic parameters in assessing impaired left ventricular function the reproducibility of haemodynamic measurements were investigated at rest and during supine exercise on a bicycle ergometer in fifty-one patients suspected of arteriosclerotic heart disease by means of a Swan-Ganz pulmonary artery thermodilution catheter and ...

A 70-year-old South African long-distance runner, holder of his age group's marathon record and former Olympic marathon runner, was studied to determine the effects of 52 years of regular training on functional capacity and health. Maximal treadmill exercise testing revealed no ischaemic ECG abnormalities and an excellent functional capacity (58,6 ...

The hemodynamic effects of 0.1 mg/kg verapamil given intravenously to 7 patients with angina pectoris were studied at rest and during exercise in the supine position. Cardiac output was measured with the thermodilution technique, which permitted measurements every 30 sec during exercise. Maximal exercise tolerance increased significantly after verapamil. Verapamil ...

Symptoms of congestive heart failure occur most commonly during exercise, but cardiac performance is usually quantitated at rest. The relation between exercise capacity and measurements of cardiac performance at rest is little known. Treadmill exercise was performed in 21 patients with heart failure due to cardiomyopathy. Exercise duration averaged 9.1 ...

The cardiac profile of nine AIAW softball champions (SC) was compared with the cardiac profile of 10 sedentary women who were matched according to age and body size (SW). Standard M-mode echocardiography and a maximum graded stress test were performed on each subject. The mean (+/- SE) resting heart rate ...

Regional right ventricular (RV) motion was examined in six acutely instrumented dogs by implanting radiopaque markers in three regions of the free wall: the apex, the midventricle, and the outflow tract. These markers were filmed at the paced heart rate of 180 beats/min with a high-speed biplane X-ray system, and ...

The maximal width of the third ventricle, the maximal distance between the outer tips of the anterior horns, and the number of enlarged cerebral sulci on the two highest CT slices were measured in 68 chronic schizophrenic patients on cranial computed tomograms in order to detect a possible enlargement of ...

The intraventricular conduction time was measured during rest, exercise, and recovery in five patients who developed acute left anterior hemiblock during exercise-induced myocardial ischemia. The A QRS shifted from 58 +/- 17 degrees at rest to -66 +/- 11 degrees during exercise (p less than 0.001). The intraventricular conduction time ...

Haemodynamic studies at rest and during exercise before and after digitalization were carried out in 11 patients with vascular disease. Haemodynamic parameters at rest were within normal limits except for one patient, who had a cardiac index (CI) below 2.51/min/m2. During exercise 7 of the patients showed impaired left ventricular ...

Nine healthy male subjects ages 18-27 exercised five days per week. Three days per week they performed five repetitions of squats, leg extensions and leg flexions with maximal resistance for a total of 11 sets. On the other two days each week subjects performed five leg presses and 20 calf ...

Two cases of ventricular fibrillation occurring during a physician-directed exercise program are described. Both were successfully resuscitated. No single clinical parameter can predict which patient is at increased risk for exercise-induced ventricular fibrillation. We conclude that all cardiac patients who wish to exercise should do so only with physician supervision.

Cardiac arrhythmias, investigated in 1000 persons subjects to a submaximal exercise test, showed an incidence of 6%. The most frequent were the ventricular premature beats, related in more than half of the cases to an organic, probably ischemic, heart disease. Left bundle branch block and ventricular tachycardia were rare and ...

The effect of submaximal exercise at steady workload on left-ventricular systolic time intervals (STI) was studied in healthy subjects. In group I (22 subjects) 20% glucose solution was injected intravenously in a dose of 2.5 ml/kg of body weight before the exercise. In group II (20 subjects) the same exercise ...

Prognostic significance of ambulatory electrocardiographic monitoring and exercise testing was studied in 144 patients with established ischemic heart disease. A follow-up study showed that 10 sudden deaths occurred within 2 years. The univariates most strongly associated with the subsequent occurrence of sudden death included reduced maximal exercise heart rate, exercise-induced ...

We studied the respiratory and circulatory effects in six healthy supine volunteers of continuous negative-pressure breathing (CNPB) at -15 and -30 cmH2O at rest and during dynamic leg exercies at 50% of individual working capacity. CNPB had no significant effects on respiratory minute volume, tidal volume, or arterial carbon dioxide ...

Normal or near-normal exercise capacity has been thought to reflect normal left ventricular function. Many compensatory mechanisms could preserve exercise capacity in patients with severe left ventricular dysfunction. We evaluated exercise capacity using a treadmill exercise test in 26 patients with severe left ventricular dysfunction defined by a left ventricular ...

Exercise, a physiologic stress, has been used in adults to unmask abnormalities of left ventricular hemodynamics not detectable at rest. Similar data in children are not available. An evaluation was made of the feasibility, safety and value of a graded upright and supine ergometer stress test to assess exercise hemodynamics ...

To determine the clinical status, the occurrence of chronic ambulatory arrhythmias, and the prognosis of patients with exercise-induced ventricular tachycardia, 26 patients with ventricular tachycardia during or immediately following exercise on a treadmill were evaluated. Of the 26 patients, 16 had coronary arterial disease, two had nonischemic cardiomyopathy, and eight ...

The effect of symptom-limited maximal treadmill exercise was evaluated in 34 patients with sickle cell trait (SCT) and 43 controls. Systolic time intervals were measured before and after exercise in 15 of the sickle cell trait subjects, and in 11 controls. Rate pressure product, degree of ST segment depression and ...

Effective future research on the significance of ventricular premature beats (VPB) and their therapeutic suppression require improved and simpler methods for arrhythmia detection, characterization, and measurement. This study considers the comparative yield, repeatability, and validity of several methods of VPB detection and induction in a sample of the general population ...

Twenty-five children and young adults with complete heart block and 50 normal control subjects were maximally exercised on a treadmill and their electrocardiograms were analyzed for the presence and degree of ventricular ectopy activity. Sixty-eight % (17 of 25) of the heart block patients and significant ventricular ectopy (frequent unifocal ...

The successive deterioration of left ventricular pump function during exercise-induced angina pectoris was studied in 20 candidates for aortocoronary bypass surgery. Left ventricular stroke work and power were calculated from continuous left ventricular pressure recordings and repeated measurements of cardiac output every 30 sec using the thermodilution technique. The average ...

The effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias and their relation to sudden death was examined in 102 patients with stable angina pectoris randomly assigned to medical and surgical therapy (54 and 48 patients, respectively). Symptom-limited treadmill tests were performed at entry and at 1 and 5 ...

Changes in left ventricular performance were evaluated in 14 patients with functional New York Heart Association class III or IV chronic heart failure before and after the addition of oral hydralazine to conventional therapy. With conventional therapy, cardiac output increased from 3.4 +/- 0.8 (mean +/- 1 standard deviation) at ...

The effects of supine isometric handgrip and graded isotonic bicycle ergometer exercise on left ventricular performance were studied echocardiographically in 20 normal subjects, aged 18 to 36. Measurements of the left ventricular minor axis diameter were taken from recordings performed at rest, during each form of exercise, and during recovery. ...

A simple technique for obtaining high-quality echocardiograms of the left ventricle during upright bicycle exercise is described. The use of this method has resulted in left ventricular dimension data that are consistent with the results of studies in conscious, previously instrumented dogs during running. Careful subject selection is important, however, ...

The risk of instantaneous death due to ventricular fibrillation was compared in resting and exercised dogs. Three weeks before testing, all dogs had bipolar left ventricular stimulating electrodes implanted and a reversible snare was placed around the anterior descending coronary artery. The dogs were randomly assigned to either an exercise ...

Changes in left ventricular size may be of importance in the development of angina and in its amelioration by glyceryl trinitrate, but left ventricular dimensions have not been measured during exercise in the upright position, the circumstance in which angina most often occurs. To assess changes in left ventricular end-systolic ...

Left ventricle dimensions and wall stress were measured echocardiographically before and immediately after exercise in 14 athletes and 7 control subjects. Our findings suggest that afterload is an important determinant of cardiac performance and wall hypertrophy in athletes. In spite of major changes in heart rate and blood pressure, left ...

We studied the conditioning effects of chronic infusion of dobutamine and exercise training in three groups of chronically instrumented dogs. One group was infused with normal saline, a second group was infused with dobutamine (40 mug/kg per min), and the third group was exercised on a treadmill at 4 mph, ...