The Use of Exercise Testing in Children to Evaluate Abnormalities of Pacemaker Function not Apparent at Rest

The purpose of this study was to evaluate the use of exercise testing in identifying abnormalities of pacemaker function and in confirming set parameters not apparent at rest in children with implanted atrial synchronous physiologic pacemakers. Maximal exercise tests were performed on 24 children (15 boys, 9 girls) from 4.5 to 18 years of age (median =15) with physiologic pacemakers. The lower rule limit was observed before or following testing in 19 of 24 cases. In each case this correlated with the set lower rate limit. The upper rate limit was readied in 10 of 24 cases and was found to be lower than that programmed in one case in which a long atrial refractory period had limited the upper rate limit. Six children reached the maximum upper rate limit to which their pacemaker could be programmed. No abnormalities of atrial capture or ventricular capture occurred during exercise testing. Ventricular sensing was normal in each case. Atrial sensing was observed to be normal in 15 of the 24 cases. Two patients had decreased atrial sensing with exercise. Reversion to the “noise rate” due to myopotential inhibition was found in seven other cases. Subsequent tests on two of these children showed normal sensing. We conclude that: (1) maximal exercise testing identifies aspects of pacemaker function not apparent at rest; decreased atrial sensing and myopotential inhibition are the problems most commonly observed; (2) maximal exercise testing is of value in confirming programmed pacemaker parameters in a population of children with physiologic pacemakers; and (3) because six children reached the maximum upper rate limit of the pacemaker, higher upper rate limits than those currently available may be optimal for pacing in children. Exercise testing is recommended in follow‐up of the child with a physiologic pacemaker.