Intermittent left bundle branch block: an overlooked cause of electrocardiographic changes that mimic high-grade stenosis of the left anterior descending coronary artery.

Context: The electrocardiographic (ECG) pattern of high-grade stenosis of the left anterior descending coronary artery (LAD) is important clinically because of the high risk of myocardial infarction and cardiac death if the pattern is not recognized. Although the recognition of this pattern is currently widespread, false-positive ECG changes that mimic this pattern are infrequently reported.

Objective: To demonstrate that ECG changes from intermittent left bundle branch block (LBBB) and cardiac memory can mimic anterior ischemia.