ROLE OF RIGHT-VENTRICULAR AND PULMONARY FUNCTIONAL ABNORMALITIES IN LIMITING EXERCISE CAPACITY IN ADULTS WITH CONGENITAL HEART-DISEASE

This study evaluates right ventricular (RV) and pulmonary function dur ing exercise in adults with congenital heart disease (CHD). Thirty-one patients with CHD involving the right side of the heart underwent sym ptom-limited bicycle exercise testing with simultaneous expired gas an alysis and measurement of RV ejection fraction (EF). Twenty-one age-ma tched normal controls underwent the identical exercise protocol, Maxim al oxygen consumption was lower in the CHD than in normal controls (19 .5 +/- 6.4 vs 30.5 +/- 0.8 ml/kg/min, p = 0.0001 patients vs controls) . Both heart rate (156 +/- 25 vs 771 +/- 13 beats/min, p = 0.01) and o xygen pulse (9.3 +/- 3.7 vs 12.3 +/- 3.7 ml/beat, p = 0.01), an indire ct measure of stroke volume, were found to be lower in the CHD group a t peak exercise, Pulmonary dysfunction wets evidenced in the CHD group by decreased forced expiratory volume, forced vital capacity and maxi mum voluntary ventilation, and by a higher ventilation/expired carbon dioxide ratio at peak exercise (37.2 +/- 6.9 vs 33.0 +/- 5.4, p = 0.02 ), suggesting an increase in dead space ventilation. Maximal oxygen co nsumption was lower in patients whose RVEF decreased with exercise (17 .6 +/- 5.4 vs 22.8 +/- 6.4 ml/kg/min, p = 0.03 ''decrease RVEF'' group vs ''increase RVEF'' group). Maximal oxygen consumption correlated wi th the change in RVEF only in the group whose RVEF decreased with exer cise (r = 0.5, p = 0.03), In the group that had increased RVEF with ex ercise, maximal oxygen consumption correlated with forced expiratory v olume (r = 0.7, p = 0.02), Thus, adults with CHD have a reduced functi onal capacity compared with normal controls. This phenomenon appears t o be associated with both RV and pulmonary abnormalities. (C) 1997 by Excerpta Medica, Inc.