Worth Remembering: Cardiac Memory Presenting as Deep Anterior T-Wave Inversions Explained by Intermittent Left Bundle Branch Block

Cardiac memory is a common cause of deep T-wave inversions (TWI) in the anterior precordial leads and can be difficult to distinguish from alternative causes of TWI such as myocardial ischemia. Cardiac memory is generally a benign condition except in the setting of prolonged QT when it can contribute to the precipitation of torsades de pointes. Herein, we describe the presentation and clinical course of a case of cardiac memory due to intermittent left bundle branch block (LBBB) that presented asymptomatically to our outpatient cardiology clinic with deep anterior TWI. We discuss common causes of and mechanisms underlying cardiac memory and how to distinguish it from alternative causes of TWI based on 12-lead electrocardiogram. In conclusion, intermittent LBBB is an under-recognized cause of cardiac memory that can present as deep anterior TWI mimicking cardiac ischemia, and awareness of this clinical entity may help prevent unnecessary invasive and expensive testing on otherwise healthy patients.