Exercise testing for arrhythmia. Children and adolescents

The physiologic effects of exercise alter the electrical conduction of the heart. Changes in intrinsic sympathetic and parasympathetic activity and in exogenous stimuli to the heart seem to change the substrate for rhythm disturbance. The major clinical use of any medical test is its predictive value. For primary rhythm disturbances, the main benefit of exercise testing appears to be its negative predictive value. More study is needed to determine its positive predictive value. The opposite appears to be the case with secondary arrhythmia. Induction of arrhythmia during exercise is more predictive than is noninduction or suppression.