Exercise testing and ambulatory electrocardiographic monitoring following surgical repair of tetralogy of Fallot.

To evaluate the prevalence of arrhythmias and conduction disorders in patients with successful repair of tetralogy of Fallot, 38 patients undertook maximal treadmill exercise tests and 24 h electrocardiographic monitoring. Age at surgery ranged from 2 to 23 years with a median of eight years. In the recovery period following exercise, two patients developed transient 1° AV block and one patient had 2° AV block. During exercise three patients developed transient arrhythmias and during 24 h monitoring, two patients had frequent ventricular ectopic complexes. Arrhythmias and conduction disorders were more common in those patients who had been operated upon at a relatively older age but were much less common than in previous reports.