Surgical correction of pectus excavatum frequently results in subjective improvement of exercise tolerance. Whether or not cardiac function improves after repair remains controversial and has primarily been limited to isolated case reports. The purpose of this investigation was to assess changes in cardiac function during rest and exercise associated with the surgical correction of this deformity. First-pass radionuclide studies during upright rest and bicycle exercise were performed on 13 patients before and at least 6 months after pectus excavatum repair. Operation did not change left ventricular ejection fraction or cardiac index at rest or during exercise. However, the left ventricular end-diastolic volume index and stroke volume index increased at rest after surgical correction. The estimated resting right ventricular end-diastolic volume also increased markedly after operation and was associated with a decrease in right ventricular ejection fraction. These data show no limitation in exercise cardiac function that could be relieved by pectus repair. However, the increase in right and left ventricular volume after operation suggests that some cardiac compression is relieved by operative repair.