MAXIMAL EXERCISE STRESS-TESTING IN EVALUATION OF ARRHYTHMIAS IN CHILDREN - RESULTS AND REPRODUCIBILITY

To assess reproducibility in evaluating arrhythmias in children, two maximal treadmill exercise tests using the Bruce protocol were performed an average of 3.1 months apart in 19 children aged 5 to 16 years (mean 11) with chronic idiopathic ventricular (Group 1) and supraventrlcular (Group II) arrhythmias. The performance of each child during the two tests was not statistically different with regard to maximal heart rate achieved or duration of exertion; all but one child achieved expected maximal heart rates. in Group I, eight of nine children with ventricular premature complexes at rest showed suppression of the arrythmia during exercise at similar heart rates on both tests. In one child, ventricular premature complexes were not diminished in either test. One child with accelerated idioventricular rhythm and one with ventricular parasystole had reproducible arrhythmia suppression during exercise. One child with known episodes of ventricular tachycardia had this arrhythmia induced by exercise on both tests. In Group II, five children with supraventricular or junctional premature complexes at rest showed reproducible arrhythmia suppression on exercise, but one unexpectedly manifested ventricular premature complexes and one manifested runs of ectopic atrial rhythm during both exercise periods. Two children with severe sinus bradycardia achieved expected maximal heart rates. One unexpectedly manifested reproducible supraventricular premature complexes after exercise. Comparison of results of exercise testing with ambulatory electrocardiographic monitoring showed that in four patients testing uncovered arrhythmias not evident on monitoring, whereas in one patient severe sinus bradycardia occurred only during monitoring. These results indicate that maximal treadmill exercise for evaluation of arrhythmias can be performed in children using standard methodology and can yield important data reproducibly. © 1979.