Because there is controversy regarding the clinical relevance of exercise-induced ventricular arrhythmias, we analyzed their significance in 383 patients who had undergone both exercise thallium-201 stress-testing and cardiac catheterization. Two-hundred twenty-one patients (58%) had no exercise-induced ventricular arrhythmias while 162 (42%) did. There was no difference between patients with and ...

Twenty children and adolescents treated orally with atenolol for chronic paroxysmal ventricular tachycardia (n = 10) or Long QT Syndrome (n = 10) over a 5 year period were retrospectively evaluated to ascertain the efficacy of arrhythmia suppression, the effective dosage, the cardiovascular effects, and the incidence of adverse effects. ...

Regional alterations in myocardial substrate uptake and/or utilization have been demonstrated in rats with hypertension. To determine whether alterations in left ventricular fatty acid uptake and/or utilization are present in patients with left ventricular hypertrophy (LVH), we compared the results of rest and exercise iodine-123 phenylpentadecanoic acid (IPPA) myocardial scintigraphy ...

From among subjects who were examined by submaximal exercise testing in 1987, 54 were selected in order to examine the relationship between the blood pressure response during exercise and the tendency to develop left ventricular hypertrophy. Only those subjects having resting systolic blood pressure values between 120 mmHg and 140 ...

PURPOSE: To elucidate determinants of abnormal left ventricular functional responses to exercise in hypertensive patients. PATIENTS AND METHODS: One hundred twenty-seven patients with uncomplicated essential hypertension were studied by rest and exercise radionuclide angiography and by echocardiography at rest. RESULTS: The 24 patients with subnormal left ventricular ejection fraction at ...

We studied the effect of maximal exercise on the prevalence of arrhythmias in 122 subjects with severe COPD. At rest, ten subjects had supraventricular arrhythmias while 13 had unifocal VPB greater than or equal to 6/min or ventricular bigeminy. At peak exercise, six subjects had supraventricular arrhythmias while 24 had ...

The effects of xamoterol 0.2 mg kg-1 i.v. and placebo on left ventricular function at rest and on exercise were compared in patients with left ventricular dysfunction due to ischaemic heart disease. Improvements were seen in systolic and diastolic function at rest, and at up to 50% of maximal exercise, ...

To assess the effects of age on left ventricular performance, multistage supine ergometer exercise radionuclide ventriculography (RNV) was performed in 92 normal subjects. The subjects ranged in age from 24 to 86 years and were free of cardiopulmonary disease and diabetes. Age-related changes in exercise duration, left ventricular end-diastolic volume ...

Calcium antagonists are popular therapeutic agents in the treatment of systemic hypertension. Although these agents have similar antihypertensive efficacy, they have varied effects on left ventricular function at rest in hypertensive patients. The effect of different calcium antagonists on left ventricular function during exercise and on exercise performance in patients ...

To assess the short-term behavior of the right ventricle anterior papillary muscle extrasystoles (APME) based on Holter recording and exercise data, 20 subjects (age 31.5 +/- 13.7 years) with otherwise normal electrocardiogram were studied. APME was diagnosed when it resembled LBBB morphology, with downward oriented AQRS in the frontal plane, ...

STUDY OBJECTIVE - The aim of the study was to verify the reproducibility of a canine model of treadmill exercise induced regional myocardial dysfunction designed to mimic exertional angina pectoris in man. DESIGN - Dogs trained to run on a treadmill were chronically instrumented with a microtip manometer in the ...

Exercise testing is an important noninvasive method for the exposure of arrhythmias. It provides complementary information to that obtained from ambulatory monitoring or electrophysiologic testing. By producing a number of important physiologic changes, especially activation of the sympathetic nervous system and an increase in circulating catecholamines, exercise testing provides a ...

A new cardioselective beta 1-adrenergic receptor agonist xamoterol (Corwin) has been developed for the treatment of heart failure. To study the acute hemodynamic effects of xamoterol, 24 patients, 39-70 years old, with mild-to-moderate postinfarction left ventricular dysfunction entered a double-blind, between-patient comparison of a single 5-minute intravenous infusion of xamoterol ...

To examine the functional consequences of the greater increase in right ventricular work with exercise, the effects of prolonged exercise on the right and left heart chambers were compared in 41 athletes before, at the finish (13 min) and after recovery (28 h) from the Hawaii Ironman Triathlon (3.9 km ...

In order to assess the effect of acute, reversible myocardial ischemia on the outcome of programmed ventricular stimulation (PVS), ventricular stimulation was performed at rest, during exercise, and during recovery in 10 patients with coronary artery disease. Of these ten patients, four were tested while off antiarrhythmic drugs and six ...

The influence of the electrocardiographic diagnosis of left ventricular hypertrophy on exercise performance was assessed in 101 hypertensive patients and 37 control subjects referred to an exercise testing laboratory. Maximal exercise capacity was measured by the duration of a symptom-limited, treadmill test using the modified Bruce protocol. The Romhilt-Estes point ...

We have examined the effects of magnesium replacement therapy upon post-exercise heart rate and incidence of ventricular premature beats (VPB) in digitalised patients with AF. In 11 such patients, all of whom had serum magnesium concentrations of less than 0.85 mmol/l, treatment with magnesium glycerophosphate was associated with a significant ...

The maximal aerobic power of endurance athletes is high and their heart is characterized by a larger left ventricular internal dimension than in non-athletes, and a proportional increase of wall thickness; these traits may be inherited and/or the consequence of intense physical training. To assess the influence of inheritance on ...

A thirty-five-year-old woman without organic heart disease who has exercise-induced ventricular arrhythmias suppressed by propranolol and diltiazem is reported. Treadmill exercise provoked reproducibly nonsustained ventricular tachycardia (NSVT) and salvos of ventricular premature contraction (VPC). QRS morphology of these ventricular arrhythmias showed left bundle branch block pattern and right axis deviation. ...

Bunazosin hydrochloride (Detantol) was administrated in 3-mg oral doses to 10 patients (6 males and 4 females, average 49.9 years) with dilated cardiomyopathy (DCM) of class II in the NYHA functional classification. The patients were observed for changes in their hemodynamics at rest, chest X-ray, echocardiography, humoral factors and symptom-limited ...

Electrophysiological effects, antiarrhythmic activity and kinetics of levorotatory disopyramide (R(-) DP) and racemic disopyramide (equimolar mixture of R(-) DP and S(+) DP) were compared in patients with ventricular arrhythmias. This double blind cross-over randomized trial was achieved, at steady-state, following oral administration of 200 mg three times a day. In ...

An exercise test was performed in 306 patients who had had acute myocardial infarction one year previously. The five year cumulative coronary heart disease mortality was 40.0%, when the test had to be discontinued because of ventricular arrhythmias but only 13.0% if discontinued because of fatigue (P less than 0.05). ...

Frequent or repetitive exercise-induced ventricular ectopic beats are often considered a marker for serious cardiac disease or sudden death, or both. However, the prognostic value of these arrhythmias in an unreferred asymptomatic community-dwelling population over a broad age range is unknown. Of 1,160 subjects aged 21 to 96 years who ...

The long-term prognosis for 314 patients with hypertrophic cardiomyopathy (HCM) and 82 with dilated cardiomyopathy (DCM) was investigated in an attempt to elucidate clinical variables predicting sudden death (SD). In the patients with HCM, 68% of cardiac deaths occurred suddenly and unexpectedly. Variables associated with an increased risk to SD ...

To assess the accuracy of the exercise-induced decrease in the ratio of peak flow velocity in atrial systole to that in early diastole (A/E) for predicting an elevation of left ventricular filling pressure, supine bicycle ergometer exercise testing was performed in 27 consecutive patients with coronary artery disease. Doppler-derived transmitral ...

In a study of aerobically perfused rat hearts, the in situ photoactivation (530-590 nm) of rose bengal (a process that leads to the production of singlet oxygen and superoxide) has been shown to lead to the rapid development of electrocardiographic abnormalities and arrhythmias. With rose bengal concentrations of 1,000, 500, ...

Left ventricular filling pattern was assessed by pulsed Doppler echocardiography at rest and during handgrip exercise in 33 healthy middle-aged subjects. The peak mitral flow-velocities during the early rapid filling phase (E) and during late (atrial) filling (A) were measured and the ratio of these peak flow-velocities (E:A ratio) was ...

To evaluate DT during a low-level exercise test, the relation between DT and heart rate was studied by ear densitography in the late phase of hospitalization for acute MI. None of the patients had an ischemic electrocardiographic response. The patients were divided into two groups: group 1 was comprised of ...

To evaluate left ventricular systolic and diastolic function in patients with pulmonary hypertension secondary to chronic pulmonary diseases, 86 patients were studied using equilibrium radionuclide angiography with forward and reverse gating from the R wave. At rest left ventricular function, both in systolic and diastolic properties, in patients with pulmonary ...

To assess left ventricular structure and function at rest and during exercise in endurance athletes, 10 elite marathon runners, aged 28 to 37 years, and 10 matched nonathletes were studied by echocardiography and supine bicycle ergometry. Each athlete's best marathon time was less than 2 h 16 min. Echocardiography was ...

Proarrhythmic effects of flecainide acetate have been reported during exercise, but the mechanism for the arrhythmogenic interaction between flecainide and exercise is unknown. We hypothesized that the sinus tachycardia of exercise may enhance flecainide-induced conduction slowing by increasing use-dependent sodium channel blockade, thereby facilitating the occurrence of ventricular reentry. To ...

Impaired diastolic function has been described in healthy elderly subjects. Pulmonary blood volume (PBV) changes with exercise have been associated with left ventricular dysfunction, but not directly related to diastolic abnormalities. Exercise-induced relative changes in PBV were measured using gated blood pool imaging with count density comparisons over the lung ...

The effects of calcium channel antagonists and an agonist on susceptibility to ventricular fibrillation were investigated using chronically instrumented dogs with a healed anterior wall myocardial infarction. Three to 4 weeks after the infarction, a 2-min coronary occlusion was initiated during the last minute of exercise and continued for 1 ...

Treadmill exercise electrocardiography (TE) was recorded in 50 patients to evaluate the incidence of exercise-induced ventricular arrhythmias (VAs) in a group of patients who underwent corrective surgery of tetralogy of Fallot (TF) more than four years previously. The results of rhythm evaluation were correlated with cardiac catheterization data as well ...

The performance of the Bayesian feedback method for predicting lignocaine dosage developed by Vozeh et al. was evaluated in 53 Japanese patients, treated for either suppression or prophylaxis of ventricular arrhythmias, with respect to accuracy, precision, efficiency, and safety. The lignocaine serum concentrations at 12 h (C12) and 24 h ...

Myocardial and haemodynamic responses to strenuous treadmill exercise were monitored with chronically implanted instrumentation in seven physically untrained ponies. In two other ponies, haemodynamics were monitored using a conventional catheter technique. During exercise (mean +/- sem heart rate = 203 +/- 3 beats/min), left ventricular peak systolic ahd end-diastolic blood ...

Mongrel dogs with healed myocardial infarctions were given a 2 min coronary occlusion during an exercise test. The exercise plus ischemia test induced ventricular fibrillation in nine animals. One week later, the test was repeated after pretreatment with magnesium sulfate (100 mg/kg i.v.). Magnesium prevented ventricular fibrillation in seven of ...

To investigate the relationship between left ventricular function and electrical changes during myocardial ischemia, ambulatory left ventricular function monitoring and ECG recording were made during the ergometer exercise test in 14 patients with coronary artery disease. An ambulatory ventricular function monitor consists of a small cadmium telluride (CdTe) radionuclide probe ...

1. To compare different methods of cardiac stress testing that are clinically applied in the management of coronary heart disease, 2 groups of dogs each were chronically instrumented and subjected to treadmill exercise or isoprenaline infusion in the presence of coronary stenosis. 2. It was of interest to determine differences ...

The purpose of this study was to determine the maximum shortening of ventricular refractoriness that occurs following an increase in rate and to quantitate the duration of ventricular pacing required to obtain this maximum shortening of refractoriness. The subjects of the study consisted of 41 patients who underwent a clinically ...

There is increasing evidence that the use of cocaine can trigger lethal cardiac events, including ventricular fibrillation. The mechanism responsible for these lethal cardiac arrhythmias remains to be determined. Therefore, 13 mongrel dogs were instrumented so that heart rate, left ventricular pressure (LVP), and d(LVP)/dt could be measured. After a ...

Ingested cobalt has previously been associated with the development of a congestive cardiomyopathy. Despite occasional reports of cardiomyopathy after industrial exposure to cobalt, this association remains controversial. In a study of 30 cemented tungsten carbide workers with a mean duration of exposure to cobalt of 9.9 +/- 5.3 years radionuclide ...

Exercise testing has been widely applied for the evaluation of patients with coronary artery disease. The principles underlying its use for this indication make it a useful adjunctive technique, when combined with ambulatory monitoring, to diagnose arrhythmias and monitor antiarrhythmic drug therapy. During exercise, there is a withdrawal of vagal ...

An earlier study of 25 patients who were investigated by radionuclide angiography after a Mustard procedure showed that they had had evidence of right and left ventricular dysfunction at rest and with exercise. Twenty one (mean age 17.0 years (range 13.7-20.6) 11 female patients) of the original 25 patients were ...

The cross-sectional and longitudinal data available indicate that the following conclusions are warranted concerning the effects of resistance training on the cardiovascular system. Resistance training causes increased absolute left ventricular wall thickness and left ventricular mass. These increases are not as evident when expressed relative to body surface area or ...

The results of exercise treadmill stress testing were analyzed in 64 consecutive patients presenting with either ventricular fibrillation (42%) or hemodynamically significant ventricular tachycardia (58%). Underlying diseases included coronary artery disease (55%), dilated cardiomyopathy (16%), and miscellaneous disorders (29%). Patients were additionally studied with ambulatory electrocardiographic monitoring and programmed stimulation. ...

Electrophysiologic studies (EPS) are often useful in managing patients with cardiac arrhythmias, while transcatheter ablation, an investigational technology, holds promise as a cure for many of these disorders. Hospitals seeking to establish themselves as centers for arrhythmia treatment must offer EPS; it is important, however, that they exercise caution before ...

During submaximal exercise, an alpha adrenergic vasoconstriction that opposes metabolic dilation exists in the coronary circulation. Fifteen dogs were given i.c. injections of prazosin (0.5 mg) or yohimbine (0.7 mg) to determine the participation of alpha 1 and alpha 2 adrenoceptors in the vasoconstriction during exercise. All dogs were chronically ...

The tip of an intraluminal probe was positioned in the cecum, and before and after a standard meal (greater than 800 kcal), the rapid myoelectrical activity of the right, the left, and the rectosigmoid colon in six healthy subjects was recorded. In each colonic site, we recorded two different patterns ...

This report describes the inadvertent induction of non-sustained atrial and ventricular arrhythmias due to the malfunction of a programmable cardiac stimulator. The malfunction occurred when line power resumed after a brief municipal power outage ("blackout") during an invasive electrophysiological study. The stimulator spontaneously delivered very high frequency pulses through the ...