Exercise responses in ventricular septal defect

Abstract

Most reports indicate that exercise testing in operated and unoperated VSD patients demonstrates subnormal levels of work performance, maximal heart rate response, and ventricular function. Usually, maximal oxygen consumption is normal but the ventilatory anaerobic threshold is decreased. It is important to consider, however, that many of these studies were performed during an era in which children with unoperated VSD were often physically restricted and surgical closure of the defect frequently was delayed until relatively late in childhood. Our studies of VSD patients are encouraging. These patients were operated on at such young ages that a mindset of chronic cardiovascular disability was not characteristic for the child or family. Moreover, the patients have been operated on with contemporary surgical techniques and more enlightened methods of myocardial preservation during cardiopulmonary bypass. Follow-up exercise testing of these patients over the next decades will be important to determine if abnormalities can be detected in adult patients, as the effects of atherosclerotic and hypertensive cardiovascular disease are introduced. With the current routine practice of surgical closure of significant VSDs in the first 2 years of life, it is possible that the cardiopulmonary abnormalities produced by myocardial dysfunction or progressive pulmonary vascular disease, so easily demonstrated by exercise testing, will be avoided or minimized.