Exercise-induced Arrhythmias Research Articles

Coronary bypass surgery in exercise-induced ventricular tachycardia.

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 drugs with considerably increased exercise capacity and maximal heart rate during exercise. No spontaneous or exercise-induced arrhythmias have recurred during observation periods ranging from one to four and a half years. In this subset of patients ischaemia seems to be the crucial arrhythmia-inducing factor and bypass surgery alone may therefore be therapeutic. The reduction of ischaemic exercise-induced arrhythmias may be one way by which bypass surgery reduces mortality in larger patient series.

Exercise-induced arrhythmias in diuretic-treated patients with uncomplicated systemic hypertension

Although hypertensioe 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 of 68 subjects with mild, clinically uncomplicated systemic hypertension treated chronically with diuretics alone for a median of 4.5 years was compared with that in an age-matched normotensive control group. The prevalence of exercise-induced arrhythmias was higher in the group treated with diuretics, than in the control group, 57% vs 38% (p <0.05) This difference was entirely due to the higher incidence of isolated atrial or ventricular premature complexes in the diuretic-treated patients, 44% vs 26% (p <0.05). There was no difference in the incidence of frequent (more than 10% of beats) or complex supraventricular or ventricular premature complexes between the diuretic-treated and control groups. Within the diuretic group, no difference in the incidence of simple or complex arrhythmia was found between men and women, between those with and those without rest or exercise-induced electrocardiographic abnormalities or between those with a serum potassium level of less than 3.7 mEq/liter vs those with a level of 3.7 mEq/liter or greater. Thus, patients with uncomplicated hypertension treated with chronic diuretic monotherapy do not appear to be at increased risk for major arrhythmias during aerobic exercise.

Exercise Testing and Physical Fitness in Mitral Valve Prolapse

We performed maximal graded exercise testing (GXT) in 36 consecutive young asymptomatic men with mitral valve prolapse (MVP) and compared the findings with those for a group of 27 age-matched controls. Exercise did not induce cardiac arrhythmias in the subjects with MVP, nor did they have reduced effort tolerance as measured by the duration of exercise, estimated maximum workload achieved, or their functional aerobic impairment (FAI). Only one subject with MVP had a positive exercise test at maximal effort. We conclude that in unselected asymptomatic male subjects, MVP is not associated with either exercise-induced cardiac arrhythmias or reduced exercise tolerance.

Ventricular arrhythmias induced by dynamic and static exercise in relation to coronary artery bypass grafting

The effect of coronary artery bypass grafting (CABG) on exercise-induced ventricular arrhythmias was examined in 53 patients. A bicycle exercise test and an isometric handgrip exercise test were performed before and 3 months after CABG. Exercise-induced ventricular arrhythmias were detected preoperatively in 14 patients (26%), in 13 during the bicycle test and in 11 during the handgrip test, and in 18 patients (34%) after CABG. Thus, CABG had no significant effect on the occurrence of exercise-induced ventricular arrhythmias. Nine patients had new exercise-induced ventricular arrhythmias after CABG, 8 of whom had evidence of previous myocardial infarction, whereas only 8 of the 35 patients (23%) without postoperative ventricular arrhythmias had had a previous infarction. The rate of graft patency or improvement in exercise tolerance in patients with new postoperative arrhythmias did not differ from that in patients who did not have exercise-induced arrhythmias after CABG. The results confirm that CABG has no influence on the occurrence of ventricular arrhythmias induced by physical exercise. Patients with a previous myocardial infarction appear to be prone to new ventricular arrhythmias despite successful revascularization.

Post-myocardial infarction exercise testing: clinical significance of a left ventricular function index and ventricular arrhythmias. A prospective study.

A predischarge exercise test was performed in a prospective series of 187 patients, less than 70 years old, with acute myocardial infarction. A survival analysis confirmed previous retrospective findings of a significantly increased long-term mortality in patients with a low increase in the pressure-rate-product (PRP) and/or with major exercise-induced arrhythmias. ST segment depression was without prognostic significance. By a graduated, quantitative re-evaluation of the significance of exercise-induced ventricular arrhythmias, an appropriate, significantly discriminating cutoff point for the frequency of solitary ventricular premature beats (VPBs) was found at two or more VPBs/min. Repetitive VPBs had an equal significance. The probability of 4.5-year survival in patients with these arrhythmias and a low increase in PRP was 0.49 vs. 0.85 in patients with less frequent arrhythmias and with a high increase in PRP (p less than 10(-6)).

Prognostic significance of exercise-induced complex ventricular arrhythmias in coronary artery disease with normal and abnormal left ventricular ejection fraction

Prognostic significance of exercise-induced complex ventricular arrhythmias in coronary artery disease with normal and abnormal left ventricular ejection fraction

Ventricular arrhythmias during exercise testing: Mechanism, response to coronary bypass surgery and prognostic significance

To investigate the determinants and prognostic significance of ventricular arrhythmias during exercise testing, 86 patients with such arrhythmias were identified from a consecutive series of 446 patients who underwent treadmill exercise testing and cardiac catheterization. The prevalence of these arrhythmias was 19% in the total group but increased to 30% in the 120 patients with 3-vessel or left main coronary artery disease. Patients with exercise-induced arrhythmias were more likely to have 3-vessel or left main coronary artery disease, a lower resting ejection fraction, ≥2 mm of ischemic ST depression and more severe segmental wall motion abnormalities than patients without this finding (p <0.05). Repeat exercise testing in 22 patients with exercise-induced arrhythmias after coronary bypass surgery revealed that persistence of these arrhythmias was associated with either severe wall motion abnormalities preoperatively or residual ischemic ST depression during the postoperative exercise testing. At a mean follow-up period of 5.3 years, the presence of exercise-induced ventricular arrhythmias was not associated with increased cardiac mortality in the medically treated patients.

Exercise testing in the latent phase of Chagas' disease.

Exercise stress testing was performed in 50 completely asymptomatic patients in the latent phase of Chagas' disease. In 32 (64%) abnormalities were found consisting of either abnormal ST depression, exercise-induced arrhythmias, or chronotropic incompetence. The latter was determined by comparing the heart rate response to 50 age- and sex-matched control patients without serologic evidence of Chagas' disease. In the absence of an adequate control population we can only speculate as to the significance of the ST depression and arrhythmias during exercise. However, chronotropic incompetence may be a specific marker for Trypanosomal infestation in an endemic area. It probably is an early manifestation of autonomic dysfunction secondary to Chagas' disease.

Treatment of coronary heart disease with isosorbide mononitrate ('Elantan' 20): a multi-centre study in hospital and general practice.

An open, multi-centre clinical trial was carried out in 537 hospital patients and 2138 general practice patients to evaluate the efficacy and tolerance of isosorbide 5-mononitrate in the treatment of angina pectoris. Prior to entry into the trial, angina attack frequency and acute glyceryl trinitrate consumption were assessed during previous, in most cases unsatisfactory, anti-anginal therapy. After a treatment-free washout period of 3 days, graded multi-stage exercise testing was performed and then treatment started with 20 mg isosorbide mononitrate 3-times per day. Exercise testing was repeated after 14 days' therapy and, in the case of the hospital patients, also 4 to 5 hours after the first dose of isosorbide mononitrate. At the end of the 14-day treatment period, angina attack frequency and glyceryl trinitrate consumption were again assessed. Similar results were obtained for both hospital and general practice patients. Changing to isosorbide mononitrate resulted in a marked reduction in angina frequency, with complete elimination of angina attacks in approximately half of the patients; nocturnal angina, present in approximately 20% of the patients during previous therapy, virtually disappeared during isosorbide mononitrate therapy. Exercise tolerance and performance improved in the majority of patients, with a marked increase in the number of patients able to exercise to the level at which some symptom other than angina pectoris caused them to stop. ST-depression during exercise and exercise-induced arrhythmias also showed clear reductions during isosorbide mononitrate therapy. Tolerance to isosorbide mononitrate was good, the expected 'nitrate headaches' being the only common side-effect reported. The results were such that continuation of treatment with isosorbide mononitrate after the trial was recommended by the attending physician in 77% of the hospital patients and 87% of the general practice patients.

Effect of exercise on repolarisation abnormalities in patients with asymptomatic QT prolongation.

Patients with congenital QT prolongation have an increased incidence of ventricular arrhythmias and sudden death. Altered sympathetic tone has been suggested as an important contributing factor in this syndrome. Although some patients with an increased QT interval and arrhythmias have an abnormal QT response during exercise, the effect of exercise has not been reported in patients with acquired QT prolongation without clinical manifestations. The purpose of this study was to determine the pattern of QT change with exercise in patients with QT prolongation without exercise-induced arrhythmias in order to: 1) determine the most frequent response in this group; 2) observe the effect of posture on QT changes; and 3) compare the rate of QT change with a control group. Treadmill exercise testing was performed in 10 patients (mean age 52.1 +/- 8.0 years) with a QTc greater than 0.44 s; the results were compared with 14 patients with a normal QTc (mean age 45.8 +/- 12.1 years). Patients with an increased QT interval at rest experienced a significant reduction in QT interval during exercise (0.315 +/- 0.030 s vs 0.394 +/- 0.046 s standing at rest; P less than 0.01), as cycle length was decreased from 0.732 +/- 0.175 s to 0.489 +/- 0.062 s. Patients in the control group had a similar change in QT interval (0.297 +/- 0.015 s vs 0.359 +/- 0.029 s standing at rest (P less than 0.01), with a comparable change in cycle length 0.733 +/- 0.097 s vs 0.511 +/- 0.059 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of acetylator phenotype in pharmacokinetics and adverse effects of procainamide.

The pharmacokinetics and development of antinuclear antibodies (ANAs) during procainamide (PA) therapy were studied in 35 patients with ventricular arrhythmias. Sixteen of the subjects were rapid and 19 were slow acetylators. Twenty-six of them (13 rapid and 13 slow acetylators) received PA therapy (2.4g sustained-release PA X HCl daily in three doses) for at least 16 weeks. On maintenance therapy, rapid acetylators had insignificantly lower serum PA concentrations and slightly higher N-acetylprocainamide (NAPA) concentrations than slow acetylators. The unchanged PA fraction (PA/PA + NAPA) in the rapid acetylators was somewhat lower than in the slow acetylators. Rapid acetylators excreted more NAPA in urine than did slow acetylators (p less than 0.05), whereas the difference in PA excretion was not significant. More than 80% of the given drug was excreted as PA and NAPA. Spontaneous or exercise-induced arrhythmias were recorded in 6 rapid and 8 slow acetylators. ANAs (titre at least 20) appeared in 6 rapid and 8 slow acetylators. The mean time until ANA development in rapid acetylators was only marginally longer than in slow acetylators. The results suggest that acetylation phenotyping is not of great significance in predicting the development of ANAs during PA therapy.

Exercise-induced arrhythmias in patients with prior myocardial infarction

Exercise-induced arrhythmias in patients with prior myocardial infarction

Electrocardiographic exercise testing and ambulatory monitoring to identify patients with ischemic heart disease at high risk of sudden death

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 frequent ventricular arrhythmias, complex ventricular arrhythmias revealed by 24 hour ambulatory electrocardiographic monitoring and onset of S-T segment depression during exercise testing. Groups of patients at very high and very low risk of sudden death were identified using conjunction and inclusive disjunction of the foregoing variables. The presence of bivariate and trivariate combinations was associated with an increase up to 20-fold in the incidence of sudden death. Patients with the poorest prognosis were those who stopped exercise before achieving a high heart rate and who exhibited either pronounced electrocardiographic abnormalities during stress testing or complex ventricular arrhythmias during ambulatory monitoring. Combinations of exercise variables identified patients at a very high risk of sudden death, whereas combinations of monitoring variables appeared to be preferable for defining groups of patients at very low risk. The results obtained suggest that the two methods carry different prognostic information and, therefore, may complement each other in identifying potential victims of sudden cardiac death.

The effect of acebutolol on cardiac arrhythmias in patients with chronic coronary artery disease

The effect of the beta-blocking drug acebutolol on the severity of cardiac arrhythmias and the incidence of exercise-induced arrhythmias was studied in 15 patients with chronic coronary artery disease using ambulatory Holter monitoring and bicycle ergometry. We found a significantly lower grading of arrhythmias both on long-term ECGs and during and after exercise. Furthermore, there was a significant decrease in the incidence of VPBs during and after exercise (18.15 ± 7.7 on placebo vs. 3.46 ± 1.7 on acebutolol). It is concluded that acebutolol favorably influences the incidence and severity of ventricular arrhythmias in patients with chronic coronary artery disease.

Continuous Monitoring for Ventricular Arrhythmias During Exercise Tests

Exercise stress testing is being increasingly used to verify exercise-induced arrhythmia and to aid in assessing antiarrhythmic drug efficacy. The true prevalence of ventricular arrhythmia during exercise testing is underestimated by means other than continuous monitoring. We compared the yield of ventricular premature beats (VPBs) between a continuous recording system ("trendscription") and intermittent monitoring among 39 patients undergoing a total of 50 consecutive exercise studies. By intermittent monitoring, 22 (44%) of 50 of the exercise tests demonstrated VPBs; with trendscription, 31 (62%) exhibited such arrhythmia. Most striking, however, was a sixfold increase in the disclosure of complex and repetitive forms of VPBs (56 vs nine episodes). Thus, this form of monitoring presents a cost-efficient, on-line method that allows concentration on the patient during exercise as well as clear recording of all arrhythmic events.

Instant electrocardiography. Use in cardiac exercise programs.

Instant electrocardiograms before and after physical activity were recorded three times per week for three to six months in ten patients with postmyocardial infarction angina pectoris who engaged in a physical training program. Four patients developed ST-segment depressions of over 2 mm following exercise and one of the four had associated ventricular ectopia. Three other patients had asymptomatic runs of ventricular tachycardia. Two of the latter subsequently developed ventricular fibrillation during moderate physical activity and one subsequently died suddenly at home while engaged in yardwork. Instant electrocardiography represents a simple way to screen for patients prone to exercise-induced arrhythmias. It is felt that the latter should be on antiarrhythmic drugs and be limited to rather light physical activity such as certain flexibility exercises, noncompetitive team sports, and moderately brisk walking.

Treatment of Exercise-Induced Dysrhythmias in Patients With Pacemakers

To the Editor.— I read the interesting article, "Exercise-Induced Arrhythmias in Patients With Pacemakers," by Singer et al, published inThe Journal(224:1515, 1973). Myocardial ischaemia, sympathomimetic drugs, and stress such as recent operation are the factors described that such dysrhythmias may occur in patients with pacemakers in the absence of the above precipitating factors. 1 In three of my patients, exercise might have induced the dysrhythmias. Dysrhythmias following exercise might well be related to increased circulating catecholamine levels or increased sensitivity of the myocardium to catecholamines, practolol, being a specific, competitive antagonist of catecholamine at beta-receptor sites with a marked selectivity for those in the myocardium, 2 would be a useful prophylactic agent for the patients with exercise-induced dysrhythmias after pacemaker implantation. I have demonstrated the efficacy of practolol, and adrenergic beta-receptor related to propranolol, in the treatment of pacemaker-induced dysrhythmias and also suggested its use in dysrhythmia-prone patients

Exercise-induced arrhythmias in patients with pacemakers

Exercise-induced arrhythmias in patients with pacemakers

Exercise-Induced Arrhythmias in Patients With Pacemakers

Twenty-seven patients with cardiac pacemakers performed 44 low-level treadmill exercise tests to demonstrate changes of rhythm. Many types of transient arrhythmias were induced during 33 tests (75%). Ventricular ectopic beats occurred in 26 tests (59%) including five paroxysms of ventricular tachycardia. Supraventricular rhythms occurred in 20 tests (45%): junctional, nine; normal sinus, seven; and atrial fibrillation, four. Serial exercise testing of 15 subjects revealed consistent rhythm changes. Exercise was helpful in determining pacemaker characteristics, usually illustrating an appropriate function in the demand mode. Ambulatory patients with cardiac pacemakers are often arrhythmic during walking exercise.

Exercise-induced ventricular arrhythmias in patients with coronary artery disease: Their relation to angiographic findings

Ventricular extrasystoles occurring before, during or after graded exercise testing were related to extent of coronary artery disease and to ventricular motion disorders in 81 symptomatic patients undergoing selective coronary and left ventricular angiography; the results were compared with data in 89 similar age-matched patients without arrhythmias. Compared with arrhythmia-free patients, 67 patients with exercise-induced arrhythmias had a significantly greater incidence of prior myocardial infarction, double or triple vessel disease and overall abnormal ventricular contractile patterns. Exercise induced extrasystoles occurred in only 11 percent of patients with insignificant coronary disease. Abolition of resting extrasystoles by exercise was not associated with less extensive coronary disease. Our study suggests that exercise-precipitated arrhythmias may represent a form of subclinical ischemia, signify more advanced degrees of coronary and left ventricular disease, and serve as an aid in detecting potentially high-risk patients.