Pulmonary autograft aortic valve replacement (Ross procedure) is increasing in popularity, particularly in children and young adults. We performed a controlled study of pediatric and adult Ross procedure patients to evaluate postoperative exercise valvular hemodynamics and cardiac rhythm. Thirty-one patients and 24 controls underwent stress echocardiography. Doppler and 2-dimensional echocardiography assessed valvular hemodynamics and right and left ventricular size at baseline and after exercise. Electrocardiography monitored cardiac rhythm. Patients and controls had neoaortic and neopulmonic valve insufficiency ranging from none to moderate that improved or did not change with exercise. Baseline and exercise mean peak transaortic gradients were not significantly different between patients (baseline 6.3 +/- 3.8 mm Hg, exercise 12.8 +/- 7.3 mm Hg) and controls (baseline 6.7 +/- 2.5 mm Hg, exercise 14.3 +/- 5.2 mm Hg). However, baseline and exercise mean peak transpulmonic gradients were significantly different between patients (baseline 20.7 +/- 9.6 mm Hg, exercise 45.2 +/- 23.5 mm Hg) and controls (baseline 3.7 +/- 1.3 mm Hg, exercise 10.6 +/- 3.7 mm Hg). Significant exercise-induced arrhythmias occurred in 8 patients (26%) and no controls. Occurrence of arrhythmias correlated with an older age at surgery and age at study. After the Ross procedure, patients have valve competence and transaortic gradients similar to controls at baseline and with exercise. However, patients have significantly increased baseline and exercise transpulmonic gradients compared with controls. Furthermore, exercise-induced arrhythmias occurred frequently in our patient group and were associated with an older age at surgery and age at study.