[Exercise capacity in children late after aortic valve replacement using the Konno procedure].

Between 1980 and 1996, aortic valve replacements using the Konno procedure were performed in 10 patients. In order to assess the latent problems after this procedure, the exercise capacity was evaluated in 6 patients (3 males and 3 females). Exercise stress tests by a bicycle ergometer with ramp protocol were performed and gas exchange responses using the mixing chamber method were measured. The mean age at the time of operation was 6.6 years (range 3 to 11) and the mean age at the time of exercise test was 11.4 years (range 8 to 15). All patients were NYHA class I except 2 patients who had residual PH. Maximum oxygen consumptions were 37 to 39 ml/kg/min in males and 23 to 34 ml/kg/min in females. Maximum heart rates ranged from 166 to 184 bpm and O2 pulses ranged from 4.6 to 7.1 ml/beat/BSA. In the 2 patients who had residual pulmonary hypertension, HR bursting and O2 pulse plateau & decline occurred, which may indicate presence of decreased stroke volume. In conclusion, all patients late after the Konno procedure could tolerate exercise beyond respiratory compensation and there were no arrhythmia during exercise. HR was satisfactorily increased but maximum oxygen consumption was lowered at about 70% of the normal level.