The cardiac conduction system in acute myocardial infarction. A clinicopathological correlation.

Abstract

Summary: Detailed autopsy examination of the cardiac conduction system was carried out in 30 patients with and without heart block complicating acute myocardial infarction (AMI), and the hearts of another 30 patients who died from non‐cardiac disease were used as controls in the interpretation of the histological changes. Fibrosis of the conduction tissue was prevalent in both the AMI and control patients; and among the AMI patients, appeared to be unrelated to whether there was a conduction defect. Patients with anterior infarcts more commonly had intraventricular block and infarction of the bundle branches with sparing of the proximal conduction tissue. Patients with posterior infarcts were more likely to have atrioventricular (AV) block preceded by Wenckebach phenomenon but necrosis of AV node was relatively uncommon. The His bundle electrogram was a useful clinical investigation and correlated well with the histopathology of the conduction tissue in determining the site of heart block.