Spiro-ergometric studies after corrective surgery of tetralogy of Fallot]

Treadmill exercise electrocardiography and spirometry was recorded in 61 patients (aged from 5 to 23 years) who underwent corrective surgery for tetralogy of Fallot. The Bruce-protocol and a modified interval-protocol were compared to find out their ability to induce arrhythmias. Supraventricular arrhythmias were predominantly provoked by the interval-protocol while maximal exhaustion is often necessary for inducing ventricular arrhythmias which we found in 23% of our patients. Most of them were seen in the periods of recovery between or after the exercise. We propose a combination of both protocols, which will be compared with established forms of exercise-testing in further studies. The results of rhythm analysis of consecutive exercise tests in one patient after surgical repair could possibly be compared by using an "arrhythmia score" which tries to indicate the severity of different forms of arrhythmias. The values of maximal heart rate, oxygen consumption and endurance time recorded at maximal exercise (Bruce-protocol) were about 15% lower than correspondent values of healthy persons found by other authors.