[Electrocardiogram after complete repair of tetralogy of Fallot]

207 cases of Fallot's tetralogy having undergone complete surgical correction have been studied in this work as regards the electrocardiographic changes induced by surgery. The observed anomalies were the following: --Intraventricular conduction disturbances --179 cases (86,5%) --Atrio-ventricular block --33 cases (16%) --Arrhythmias --29 cases (14%) --Myocardial infarction patterns --6 cases (2.9%). In the atrioventricular conduction disturbances, right complete bundle-branchblock was most frequently observed (126 cases, 70.4%). In 22 cases, it was combined with left anterior hemiblock, the onset of which seemed to be favoured by the previous existence of a minor left anterior hemiblock. Of the 33 cases of atrio-ventricular block which started during operation or immediately afterwards, 13 will remain permanent, 10 of which were of a high degree, requiring implantation of an intracorporeal pacemaker in 8 cases. No case of block started later on, the cases of delayed block being in fact recurrences of transient blocks which had appeared during or immediately after the operation. The candidates to sudden death by paroxysmal block are therefore patients who had a transient block during of following operation, especially if they had besides bilateral bundle-branch block. The arrhythmias were on the whole devoid of danger. 6 cases of myocardial infarction (2.9%) were observed; their incidence is therefore not negligible.