Myocardial structure of left ventricular segments with recurrent myocardial ischemia was evaluated by morphometry and compared with that of segments with normal blood supply in 15 patients with exercise-induced myocardial ischemia. Left ventricular high-fidelity pressure measurements and simultaneous biplane angiocardiography were performed in patients at rest and during supine bicycle ...

To determine whether endogenous opiates have a role in circulatory regulation during mild to moderate exercise, 11 chronically instrumented dogs were exercised on a treadmill up a 6% incline at 2.5 and 5.0 mph, each for 20 min, after treatment with either the opiate receptor antagonist naloxone (1 mg/kg bolus ...

There is lack of consistent correlation between left ventricular function at rest, haemodynamic measurements at rest, symptomatic status and exercise tolerance. Haemodynamic data appear comparable in patients whose exercise tolerance is limited clinically by fatigue and by breathlessness. Selected patients with left ventricular dysfunction and compensated congestive heart failure can ...

Indecainide, a new class 1C agent, was administered to 16 patients with a history of ventricular fibrillation or ventricular tachycardia. Evaluation of drug effect consisted of acute testing with 125 mg followed by a period of maintenance therapy. Efficacy, as evaluated with both ambulatory monitoring and exercise testing, was defined ...

Exercise performance in patients with impaired ventricular function does not correlate well with the severity of dysfunction. Patients with ventricular dysfunction can achieve a fairly high work capacity, and the physiological variables respond in a similar way, regardless of whether or not the patients do or do not have impaired ...

The anaerobic threshold (AT) has been proposed as an index to assess the functional status of patients with chronic heart failure. The focus of this report was to evaluate in post-myocardial infarction patients the utility of the AT for (a) assessing the severity of exercise-induced left ventricular impairment, (b) determining ...

Temporal signal averaging of the surface QRS (V1 + V3 + V5) was performed in 16 patients with arrhythmogenic right ventricular dysplasia and in 16 normal subjects. The differences between ARVD patients and normals were large for the filtered QRS duration (FQRSd) (146.2 +/- 18.9 ms vs. 91.8 +/- 4.1 ...

The effects of the Ca++-antagonist verapamil on hemodynamic and regional myocardial functional parameters were studied in a canine model of exercise-induced myocardial dysfunction which mimics exercise-induced angina pectoris. Six dogs, trained to submit to five treadmill exercise cycles, each consisting of 4 min of running and 11 min of recovery, ...

Clinical, angiographic and hemodynamic parameters were assessed preoperatively and 12-20 weeks (mean +/- SD: 14 +/- 2) after left ventricular anterior aneurysmectomy in 31 consecutive patients. In 18 patients, associated coronary artery bypass surgery was necessary (1.4 grafts/patient). One patient with mitral valve insufficiency postoperatively required mitral valve replacement. No ...

This study was undertaken to evaluate the effect of flecainie (Fle) and propafenone (Pro) on rest and exercise myocardial contractility after prolonged oral administration. Standardized, fully automated, gated radionuclide angiograms at rest and during maximum exercise were performed single blinded and prospectively in 19 patients before and after oral treatment ...

Digoxin-like immunoreactive factors (DLIFs) in serum may represent endogenous cardiotropic agents. We determined if blood levels of these endogenous factors changed during prolonged strenuous exercise. Total and loosely protein-bound (LPB) DLIF were measured by radioimmunoassay in the serum of nine healthy subjects during prolonged exercise to exhaustion. Mean total and ...

Left ventricular function during supine bicycle exercise was studied using multigated blood pool imaging in ten patients with tricuspid atresia after Fontan's operation and in 13 children and adults (control group). The mean age of the patients was 16 years and the mean interval between operation and study was 5 ...

The effects of captopril versus placebo on oxygen consumption in the exercising leg have been examined using Doppler measurements of femoral flow and arteriovenous oxygen difference. Twenty patients with heart failure were randomized to captopril 25 mg (N = 10) or placebo (N = 10). Maximal supine exercise of one ...

A slow growing encapsulated haemangioma of the left atrium was diagnosed by means of cross sectional echocardiography. The heterogeneous nature of the tumour was reflected in a central area of relative echolucency. After successful surgical removal of the tumour, the patient's symptoms of lethargy and limited exercise capacity improved considerably.

To determine the effects of prolonged exercise on systolic and diastolic left ventricular function, we studied 21 athletes before, at the finish (within 11 +/- 5 min), and during recovery (28 +/- 9 hr) after the Hawaii Ironman Triathlon (2.4 mile swim, 112 mile bike, 26.2 mile run). Two-dimensionally guided ...

To determine if electrical stimulation during the basic ventricular drive train introduces local effects that influence ventricular refractoriness during endocardial stimulation in humans, 10 patients were studied. With a hexapolar catheter with 3 mm interelectrode distances positioned at the right ventricular apex, the ventricular functional and effective refractory periods were ...

Alinidine and ULFS 49, two specific bradycardic agents were comparatively investigated with propranolol in a model of exercise-induced regional myocardial contractile dysfunction in dogs. Standardized treadmill exercise resulted in a marked decrease in regional function in the myocardium supplied by the critically stenosed circumflex branch of the left coronary artery. ...

In 14 patients during exercise, intravenous nitroglycerin improved anginal threshold and increased workload compared with control subjects. At similar workloads, the decreased left ventricular volumes suggested decreased myocardial oxygen consumption due to peripheral unloading. At maximal exercise with nitroglycerin (50 +/- 17 to 79 +/- 15 watts), rate-pressure product and ...

The influence of the rate of ventricular enlargement on the morphology of hydrocephalic white matter was studied and correlated with previous studies of water content. Different rates of ventricular enlargement were obtained in two groups of cats by opening either the calvaria or the calvaria and the dura mater before ...

To determine the effects of dynamic exercise on ductal left to right shunting and skeletal and myocardial blood flow distribution, a persistent ductus arteriosus was created by balloon catheters in neonatal piglets. At 8-10 weeks of age, aortic, pulmonary artery, and left atrial catheters were placed and radiolabelled microspheres injected ...

Exercise performance in 41 men with impaired left ventricular function following an acute myocardial infarction was studied. Twenty (intervention group) subsequently underwent a 4-month supervised exercise training programme in an outpatient capacity, with three sessions per week. On completion, exercise performance was compared to the 21 control patients who received ...

In this study prophylactic antiarrhythmic effects of verapamil on exercise-induced ventricular arrhythmias are evaluated. Investigations were carried out on a total of 22 patients. All patients showed frequent and/or complex ventricular arrhythmias during repeated exercise tests under control conditions. After two control exercise tests all patients were treated with verapamil ...

In a selected group of 10 apparently healthy subjects and 22 patients with organic heart disease, all with frequent ventricular ectopic beats on Holter monitoring, we assessed the influence of sympathetic activation by comparing the arrhythmogenic effects of a symptom-limited bicycle exercise stress test and 90 degree head up tilt. ...

The effects of six week, high-dose anabolic steroid treatment (methandienone, 1.5 mg/kg/day) on the changes in left ventricular function induced in dogs by endurance training were studied by a catheterization technique under anaesthesia. Pacing, isoproterenol and dextran infusions were used as loading tests (respectively). Dogs were randomized into an exercise ...

1 Because controversy exists regarding the effects of dihydroergotamine (DHE) on the performance of underperfused myocardium, the effects of DHE were investigated in a model of exercise-induced regional myocardial dysfunction in conscious dogs. 2 We also investigated a possible functional antagonism between DHE and nitroglycerin that might reduce the latter ...

The kinetics of Bacillus subtilis macrofiber helix hand inversion was examined. Inversion was induced by transfer of structures produced in one medium to another medium. When cultured at 20 degrees C in either medium, the doubling time was approximately 100 min. To establish a baseline, the macrofiber twist state produced ...

Sixty-four patients with reproducible exercise-induced ventricular arrhythmias were enrolled in an open-label, multicenter study to assess the efficacy and safety of oral nadolol therapy. There were 53 men and 11 women ranging in age from 19 to 75 years (mean 53.9). The severity of arrhythmias varied from frequent ventricular premature ...

In a group of 62 patients with chronic heart failure 29% developed ventricular tachycardia during exercise testing. The two-year survival of this group was only 22%, compared to 55% in those not demonstrating ventricular tachycardia (P less than 0.01). In a double-blind cross-over study against placebo, with three-month treatment periods, ...

The arrhythmogenic effects of exercise tests are often unpredictable, sometimes paradoxical, and usually poorly reproducible. This explains why they are rather neglected by rhythmologists in studying the mechanisms of arrhythmias and the effects of antiarrhythmic drugs and why their prognostic value is a matter of controversy. At the same time ...

Echocardiography offers many advantages for non-invasively assessing cardiac function during exercise, but the use of this technique is hampered by interference created by respirations and body motion. The persistence of alterations in ventricular dimensions in the immediate post-recovery period, however, provides an artifact-free opportunity for evaluating recovery from the inotropic ...

We studied the efficacy of propafenone in 16 patients (pts) with exercise-induced ventricular arrhythmias (VA). Propafenone was given in doses of 450 mg (13 pts) to 900 mg (3 pts) per day and was compared with placebo. An arrhythmic index was calculated by dividing the frequency and severity of VA ...

The prevalence and type of arrhythmias has been studied in a representative sample of 2000 Athenians, aged 18-81 years, who underwent exercise testing on a treadmill according to the Bruce protocol. It was found that 121 persons (mean age 55.7 +/- 14.9 years, 31% greater than 65 years), exhibited arrhythmias ...

Thirty patients with ischemic (n = 14) or idiopathic dilated (n = 16) cardiomyopathy were followed long-term to determine the prognostic value of measuring entry exercise capacity. At the time of referral for management of symptomatic heart failure, studies included radionuclide angiography, M-mode echocardiography, 24-hour Holter and graded exercise testing ...

Although fortunately rare, the serious and potentially fatal complication of air embolism continues to occur following open-heart surgery. Its reliable prevention is dependent on the avoidance of specific procedural hazards and the exercise of various maneuvers to evacuate residual air from the heart before it is allowed to eject. Specifically, ...

From the data available so far it is apparent that in patients with stable angina, bypass graft surgery is not associated with any change in ventricular premature complexes or complex ventricular arrhythmias at rest or during exercise over a 1-5 year follow-up period despite the evidence of a substantial relief ...

1. Transmural distribution of myocardial blood flow was studied using 15 micron diameter radionuclide-labelled microspheres in six normal ponies and nine splenectomized ponies at rest, and during maximal exercise performed without as well as with adenosine infusion (3 microM kg-1 min-1). The splenectomized ponies were also studied during submaximal exercise ...

Flecainide acetate, a new antiarrhythmic agent, possesses favorable pharmacokinetic and hemodynamic properties and demonstrates highly favorable antiarrhythmic activity in patients with ventricular arrhythmias. However, the proarrhythmic potential of flecainide deserves further evaluation. In 7 (13%) of 55 consecutive patients treated with oral flecainide, 200 to 600 mg/day, for complex ventricular ...

To estimate the effects of diltiazem on the left ventricular diastolic abnormalities in patients with hypertrophic cardiomyopathy, transmitral flow velocity during diastole was studied before and immediately after dynamic leg exercise with the pulsed Doppler technique combined with two-dimensional echocardiography. Seventeen patients with hypertrophic cardiomyopathy and 24 apparently healthy men ...

Among 400 consecutive patients undergoing conventional isolated bypass surgery, 9 patients had clinical and electrocardiographic evidence of severe ischaemia during exercise and serious exercise-induced ventricular arrhythmias. Four patients had spontaneous exercise-induced arrhythmias and two had been resuscitated for out-of-hospital cardiac arrest. Postoperatively all patients were free of angina, off anti-anginal ...

Isometric exercise produces a characteristic pressor increase in blood pressure which may be important in maintaining perfusion of muscle during sustained contraction. This response is mediated by combined central and peripheral afferent input to medullary cardiovascular centers. In normal individuals the increase in blood pressure is mediated by a rise ...

Twenty two patients with heart failure were studied in a double blind crossover trial to compare amiodarone (200 mg/day) with placebo. Each agent was given for three months. Extrasystoles and complex ventricular arrhythmias were common during ambulatory electrocardiographic monitoring and during exercise testing at entry to the study. Breathlessness and ...

Although the results of the 2 degrees Stiles-Burch investigation were published in 1955 in the form of mean data, individual results have not been available. It is only recently that they have been in wide demand. Since in 1955 this demand was not anticipated, individual results were left in an ...

Although hypertensive patients have been shown to have a higher prevalence of arrhythmias during ambulatory monitoring when treated with diuretic drugs than when untreated, the effects of maximal aerobic stress on arrhythmia frequency in such patients is unknown. The incidence of arrhythmias during graded maximal treadmill exercise in a group ...

Digitized M mode echocardiography was used to evaluate the effect of a competitive 24-h run on the left ventricular diastolic function in 12 well-trained marathon runners who completed 146-227 km during the race. Mitral valve opening was delayed, early diastolic filling was decreased and prolonged, and posterior wall thinning was ...

To determine the effects of exercise in experimental autoimmune myocarditis, guinea pigs immunised with heterologous heart protein (rat heart), Freund's complete adjuvant, and pertussis vaccine (treated group) were exercised on a treadmill for a total of 11 weeks and compared with non-exercise treated animals. In vivo heart rates and pressures, ...

Cardiac functional and structural adaptations to exercise-induced hypertrophy were studied in 68 pigs. Pigs were exercise trained on a treadmill for 10 wk. Sequential measurements were made of cardiac dimensions, [left ventricular end-diastolic diameter (EDD), changes in diameter (delta D%), wall thickness (WTh), wall thickening (WTh%), left ventricular pressure (LVP), ...

The influence of exercise on left ventricular diastolic filling was evaluated in 14 patients with hypertrophic cardiomyopathy (HCM) and 14 normal controls (NC) by dynamic exercise echocardiography. Using X-Y digitizer and computer, normalized peak rate of change of the left ventricular dimension during systole (pVs) and the rapid filling phase ...

M mode echocardiography was used in 10 normal subjects to study left ventricular dimension and function variables at identical heart rates during tachycardia induced by supine bicycle exercise or atrial pacing. Echocardiographic data were analysed independently by two observers. The maximum heart rate reached during atrial pacing was lower (mean ...

To evaluate left ventricular reserve in normal children 127 healthy boys and girls (71 males, 56 females) were investigated with echocardiography during supine bicycle exercise at levels of 6, 9, 12 and 15 kpm/min/kg body weight. Left ventricular function parameters were obtained from the M-mode echocardiogram, electrocardiogram and phonocardiogram. The ...

The left ventricular function of patients with essential hypertension was examined during exercise and isoproterenol (ISP) infusion echocardiography. Twenty-eight hypertensive patients without cardiac hypertrophy (Group NH), 20 patients with cardiac hypertrophy (Group HH), 7 patients with cardiac dilatation (Group D), and 13 normotensives (Group N), were studied during multistage exercise ...