Cardiac Memory-induced T-wave Inversions After Temporary Ventricular Pacing

Cardiac memory refers to T-wave inversions (TWI) on electrocardiograms (ECGs) after an episode of abnormal ventricular activation or wide electrical activity of ventricular muscles (QRS complex). We present the case of a 62-year-old woman with symptomatic bradycardia due to sinus pause. She immediately underwent temporary transvenous ventricular pacing. In the following days, intrinsic normal sinus rhythm was resumed at 69 bpm and a narrow QRS was observed (97 ms). Additionally, deep TWI was observed in leads II, III, aVF, and V3-V6. The distribution of TWI, normal echocardiogram and laboratory results, non-significant coronary angiogram, and recent right ventricular pacing correspond to possible cardiac T-wave memory. Follow-up 12-lead ECG four weeks later showed that T-wave morphology returned to normal baseline. This further confirmed the final diagnosis of cardiac memory-induced TWI. Recognizing cardiac memory-induced TWI is important for physicians to facilitate proper evaluation and management of TWI and prevent unnecessary further cardiac diagnostic tests.