Abstract 2110: Exercise Induced Ventricular Arrhythmias are not Independent Predictors of Long term Mortality in Subjects without Clinical Heart Disease
Exercise-induced ventricular arrhythmias (VAs) predict long-term mortality in patients with cardiovascular disease. The prognostic implications of VAs in subjects without clinical cardiovascular disease are not well characterized. Our study population consisted of consecutive subjects referred for symptom-limited treadmill testing during 1986–1991. Patients with known cardiovascular disease or high risk equivalents such as diabetes mellitus were excluded. All cause mortality was determined by the National Death Index through August 31, 2005. Cox proportional hazards regression was used to test the relationship between severity of VAs and all-cause mortality. Exercise-induced VAs were categorized in five groups: none (No PVC), PVC <5/min, PVC ≥5/min, pairs, and ventricular tachycardia (VT). Using No PVC as the referent, hazard ratios (HRs) for the other groups were calculated in an unadjusted model
(Model 1), in a model age-gender adjusted
(Model 2), and in a model age-gender-METs adjusted
(Model 3). Exercise tests on 7991 subjects (5914 men and 2077 women) were analyzed.
During the 16.4 ± 2.7 years of follow-up, there were 593 (7.4%) deaths. In the unadjusted model, risk of death significantly and progressively increased with increasing severity of VAs. However, with successive adjustments in Model 2 and Model 3, the progressively increased risk of death successively declined and lost significance (Figure⇓). Our results suggest that in subjects without clinical cardiovascular disease, ventricular arrhythmias during exercise do not contribute independently to prediction of long-term all-cause mortality.