Prevalence and prognosis of exercise-induced nonsustained ventricular tachycardia in apparently healthy volunteers.
Although exercise-induced ventricular tachycardia (VT), whether sustained or nonsustained, is usually associated with significant organic heart disease, its prevalence, associated characteristics and prognostic significance in an asymptomatic, unreferred community-dwelling population are unknown. Therefore, the prevalence of VT associated with maximal treadmill exercise was assessed in 597 male and 325 female volunteers, aged 21 to 96 years (mean +/- standard deviation 54 +/- 16), from the Baltimore Longitudinal Study on Aging who were without apparent heart disease. Ten subjects, 7 men and 3 women, with exercise-induced VT were identified, representing 1.1% of those tested; only 1 was younger than 65 years. All episodes of VT were asymptomatic and nonsustained. In 9 of 10 subjects, VT developed at or near peak exercise. The longest run of VT was 6 beats; multiple runs of VT were present in 4 subjects. Two subjects had exercise-induced ST-segment depression, but subsequent exercise thallium scintigraphic results were negative in each. Compared with a group of age- and sex-matched control subjects, those with asymptomatic, nonsustained VT displayed no difference in exercise duration, maximal heart rate, or the prevalence of coronary risk factors or exercise-induced ischemia as measured by electrocardiography and thallium scintigraphy. Over a mean follow-up period of 2 years, no subject has developed symptoms of heart disease or experienced syncope or sudden death. Thus, exercise-induced VT in apparently healthy subjects occurs almost exclusively in the elderly, is limited to short, asymptomatic runs of 3 to 6 beats usually near peak exercise, and does not portend increased cardiovascular morbidity or mortality rates over a 2-year period of observation.
D000328:Adult; D000368:Aged; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011379:Prognosis; D011877:Radionuclide Imaging; D013610:Tachycardia / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology