Benign persistent T-wave inversion mimicking ischemia after left bundle-branch block--cardiac memory.

The electrocardiographic presence of deep T-wave inversions in a patient presenting with chest pain is highly concerning for cardiac ischemia. There are certain situations, however, when this finding may represent a benign phenomenon. In this report, we illustrate a case of non- ischemia-related T-wave inversion after resolution of a rate-related left bundle-branch block pattern--a case of cardiac memory. This poorly understood process occurs when the heart resumes a sinus rhythm after a period of abnormal depolarization, typically a bundle-branch block or ventricular pacing. The precordial leads in these patients will demonstrate alarmingly deep, symmetrical T-wave inversions. As our case demonstrates, however, this finding is an expected consequence of the antecedent aberrant conduction pattern and has no correlation with the presence of ongoing myocardial ischemia.