[Conduction disorders in infarction. Prognosis and therapeutic impact]

The natural history of conduction disorders in infarction and their prognostic significance are now well known and determine the choice of treatment. In the acute phase of inferior infarction without bundle branch block, temporary pacing is only indicated in cases with poor clinical tolerance or with a bradycardia of less than 50. Prophylactic pacing, on the other hand, appears to be necessary in cases of anterior infarction with branch block, at least in the high risk group in which the block is recent and bifascicular. In this case, the pacemaker is only permanent in cases of high degree atrio-ventricular block in the acute phase. The subsequent prognosis of anterior infarction with branch block and without high degree atrio-ventricular block in the acute phase carries a high incidence of sudden death. Primary delayed ventricular fibrillation during the first eight weeks seems to be the cause for this sudden death. Prolonged hospital surveillance of these patients would appear to be indicated.