Exercise performance in tetralogy of Fallot after intracardiac repair

We evaluated 99 male and 36 female patients with tetralogy of Fallot 1 year or more after intracardiac repair (ICR) in 279 exercise studies between 1968 and 1979. Sixty tetralogy patients were studied serially two to nine times at 12 to 18 month intervals. Work performance and heart rate response to cycle exercise with stepwise loading (100 kg-m/min increments) were (1) related to clinical, pre- and post-ICR cardiac catheterization, surgical, and anatomic information and (2) compared to results obtained in 221 male and 157 female normal control volunteers. On the average, male tetralogy patients were shorter and weighed less than control subjects, but female tetralogy patients as a group showed no growth impairment. Many tetralogy patients had slower resting, submaximal, and final exercise heart rates than did control subjects. Work performance averaged 82% +/- 21% of predicted in male patients and 86% +/- 29% in female patients. Serial studies showed no significant changes in work performance in the majority of tetralogy patients for up to 10 years. Best work performance was found in nine varsity athletes (99% +/- 22%) and 21 patients with primar ICR (94% +/- 23%). Statistical analysis demonstrated a significant relationship between reduced work performance and residual disease, notably cardiac enlargement, increased peak systolic right ventricular pressure, pulmonic valve incompetence (PI), residual ventricular septal defect (VSD), pulmonary hypertension, and cardiac rhythm disturbances. However, in individuals work performance cannot be predicted reliably from the presence of these lesions and should therefore be measured. We conclude that exercise testing is a useful adjunct to the clinical and hemodynamic evaluation of post-ICR tetralogy.