Ms. Maurer et al., PREVALENCE AND PROGNOSTIC-SIGNIFICANCE OF EXERCISE-INDUCED SUPRAVENTRICULAR TACHYCARDIA IN APPARENTLY HEALTHY-VOLUNTEERS, The American journal of cardiology, 75(12), 1995, pp. 788-792
The prevalence, characteristics, and prognostic significance of suprav
entricular tachycardia (SVT) occurring during maximal treadmill exerci
se testing were examined in 843 male and 540 female asymptomatic volun
teers aged 20 to 94 years from the Baltimore Longitudinal Study of Agi
ng who underwent exercise testing a mean of 2.3 times between 1977 and
1991, Exercise-induced SVT occurred during a) least 1 test in 51 men
(6.0%) and 34 women (6.3%), p = NS for gender. The 85 subjects with ex
ercise-induced SVT were significantly older than tile 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 o
f exercise-induced SVT were paroxysmal SVT, with heart rates varying f
rom 105 to 290 beats/min (mean 186.3 +/- 43.3); only 16% were > 10 bea
ts in duration and only 4% of subjects were symptomatic. Nearly half (
44%) of SVT episodes occurred at peak effort. Coronary risk factors, e
chocardiographic 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 subject
s matched for age and sex, Although the incidence of cardiac events (a
ngina pectoris, nonfatal myocardial infarction, cardiac syncope, and c
ardiac death) was not significantly different between subjects (6%) an
d control group (10%) over a mean follow-vp period of 5.7 +/- 3.9 year
s, 10% of subjects and 2% of controls subsequently developed atrial fi
brillation or paroxysmal SVT, p < 0.05 by life-table analysis. Thus, e
xercise-induced SVT in apparently healthy volunteers is usually limite
d to short, asymptomatic runs occurring near peak exercise in predomin
antly older persons, is unassociated with standard coronary risk facto
rs or exercise-induced myocardial ischemia, and does not portend incre
ased cardiovascular mortality or coronary events, but does appear to p
redict a higher incidence of spontaneous supraventricular tachyarrhyth
mia over the next several years.