Methods: Ruled out those with organic cardiac disease by physical examination, echocardiography and myocardial enzyme analysis, 123 children with VPB (aged 2-17 years) were included in this study. Fifty patients were treated with anti-arrhythmic drugs (treatment group), and 73 patients were not treated with any anti-arrhythmic drugs (non-treatment group). Their heart rate, systolic pressure, diastolic pressure and total work capacity were determined by bicycle ergometer stress test.

Results: VPB disappeared in 22 patients (44%) of the treatment group and 31 patients (42.5%) of the non-treatment group. Seventeen patients in the treatment group and 22 patients in the non-treatment group underwent the bicycle ergometer exercise stress test. Compared with normal children, these patients showed no significant difference in heart rate, systolic pressure, diastolic pressure, and reserve indexes (F=3.18-4.98, P>0.05). The total work capacity was of no significant difference among the subgroups (F=3.16, P>0.05).

Conclusions: There is no relationship between anti-arrhythmic therapy and natural disappearance of VPB. VPB without organic cardiac abnormality does not influence children's heart function and exercise capacity. Exercise test is essential to patients with VPB.

Key words: ventricular premature beat; cardiovascular reserve; heart rate; blood pressure; exercise test; work capacity

World J Pediatr 2007;3(2):125-128