Prevalence and prognostic significance of exercise-induced supraventricular tachycardia in apparently healthy volunteers.

The prevalence, characteristics, and prognostic significance of supraventricular tachycardia (SVT) occurring during maximal treadmill exercise testing were examined in 843 male and 540 female asymptomatic volunteers aged 20 to 94 years from the Baltimore Longitudinal Study of Aging who underwent exercise testing a mean of 2.3 times between 1977 and 1991. Exercise-induced SVT occurred during at least 1 test in 51 men (6.0%) and 34 women (6.3%), p = NS for gender. The 85 subjects with exercise-induced SVT were significantly older than the 1,298 free from this arrhythmia (66.0 +/- 13.5 vs 49.7 +/- 18.0 years, respectively, p < 0.001). The prevalence of SVT increased with age in men (p < 0.001) but not in women. Ninety-eight percent of the 141 discrete episodes of exercise-induced SVT were paroxysmal SVT, with heart rates varying from 105 to 290 beats/min (mean 186.3 +/- 43.3); only 16% were > 10 beats in duration and only 4% of subjects were symptomatic. Nearly half (44%) of SVT episodes occurred at peak effort. Coronary risk factors, echocardiographic left atrial size (3.3 +/- 6.7 vs 3.3 +/- 0.6 cm), and the prevalence of exercise-induced ischemic ST-segment depression (11% vs 13%) were similar in 85 subjects with SVT and 170 control subjects matched for age and sex.(ABSTRACT TRUNCATED AT 250 WORDS)