RIGHT-VENTRICULAR DIASTOLIC FUNCTION 15 TO 35 YEARS AFTER REPAIR OF TETRALOGY OF FALLOT - RESTRICTIVE PHYSIOLOGY PREDICTS SUPERIOR EXERCISEPERFORMANCE

Background We have shown previously that transient right ventricular r estriction after tetralogy of Fallot repair prolongs postoperative cou rse. This is a prospective study of right ventricular diastolic perfor mance in late follow-up patients. Methods and Results We studied biven tricular function, using Doppler echocardiographic examination. Pulmon ary arterial, tricuspid, and mitral valves and superior vena cava Dopp ler spectrals were obtained in 41 patients (mean age, 28.8 years), 15 to 35 years (mean, 23.6) after complete repair of tetralogy of Fallot. Patients were considered to hade evidence of right ventricular restri ction if antegrade diastolic flow was detected in the main pulmonary a rtery, coinciding with atrial systole (A wave), throughout the respira tory cycle. Exercise function was measured by graded treadmill testing with respiratory mass spectrometry. Three patients were excluded beca use of pulmonary outflow obstruction (Doppler gradient >40 mm Hg) or r esidual intracardiac shunts. Of the 38 patients, 37 were in sinus rhyt hm. Twenty (52.6%) had definite evidence of restriction with an A wave in the pulmonary artery, augmented during inspiration. In all 20 case s, there was superior vena caval flow reversal with atrial systole. Bo th inspiratory and expiratory transtricuspid E-wave deceleration time was significantly shorter in the restrictive group (P<.003 and P<.03, respectively). All patients had Doppler evidence of pulmonary regurgit ation, but its duration was shorter in the restrictive group (P<.01) d uring inspiration. Cardiothoracic ratio was significantly lower in the restrictive group (P<.01), suggesting less severe pulmonary regurgita tion. Both restrictive and nonrestrictive groups had reduced exercise MVO(2) compared with healthy age- and sex-matched control subjects, bu t those with restrictive physiology had significantly better maximum o xygen uptake than the nonrestrictive group (P<.001). Conclusions Isola ted right ventricular restriction late after tetralogy of Fallot repai r is common. Although it reflects abnor mal hemodynamics, the A wave c ontributes to forward pulmonary arterial flow and shortens the duratio n of pulmonary regurgitation. Consequently, there is less cardiomegaly and improved exercise performance in those patients.