Abstract

Acute heart block is most likely to occur during the first few days after myocardial infarction and does so in about 5% of patients with this condition. When the infarct is inferior, the artery to the atrio-ventricular node may be affected, producing varying degrees of transitory heart block but often with a narrow QRS complex. The prognosis of patients with such limited lesions is relatively good, the mortality being about 25%.¹ This contrasts with a mortality of about 80%, despite pacing, for those patients with an anterior infarction complicated by complete block, where the myocardial damage is always extensive and the QRS usually broad.