ECG diagnosis of acute myocardial infarction in patients with bundle branch block.

The ECG diagnosis of myocardial infarction in the setting of bundle branch block is one that most physicians find difficult and that many erroneously believe to be impossible. Two case reports of a patient with right bundle branch block and of a patient with left bundle branch block are presented to illustrate instances in which the ECG diagnosis of myocardial infarction was both possible and essential. Methods for detecting ECG changes that indicate acute myocardial injury in the patient with bundle branch block are presented and applied to these cases.