Hemodynamic abnormalities in response to supine exercise in patients after operative correction of tetrad of Fallot after early childhood.

The exercise hemodynamic values in two groups of patients with repaired tetrad of Fallot (eight patients with some residual pulmonary insufficiency and seven patients without insufficiency) were compared with values in seven patients with trivial pulmonary stenosis who had not been operated on. The patients with tetrad of Fallot underwent surgery after age 8 years and all had a good hemodynamic repair (no shunts and a right ventricular systolic pressure at rest of less than 60 mm Hg). Exercise increased the right ventricular outflow tract gradient by the same magnitude in all three groups of patients. However, both surgically treated groups experienced impaired cardiac pump function on supine exercise (that is, a lower than anticipated cardiac index for the amount of oxygen consumed and a significant decrease in stroke index). Exercise also caused both groups with repair to have a decrease in stroke index and a concomitant increase in right ventricular end-diastolic and pulmonary wedge pressures; in contrast, the patients with pulmonary arterial stenosis had an increase in stroke index and a concomitant decrease in right ventricular end-diastolic and pulmonary wedge pressures. These findings indicate that an impaired cardiac response to supine exercise can occur in patients in whom intracardiac repair of tetrad of Fallot was performed after early childhood, even though they have had a good hemodynamic repair. In addition, the impaired cardiac response to supine exercise in these patients was probably due largely to an altered myocardial compliance rather than to either residual pulmonary stenosis or pulmonary insufficiency.