Cardiac memory

Cardiac memory Cardiac memory is the persistence of T wave changes in the ECG after normalization of a wide QRS rhythm [1]. It is a remodeling phenomenon of cardiac repolarization when there is a change in the ventricular depolarization for a period of time. It can occur after ventricular pacing, transient bundle branch block, intermittent pre-excitation, ventricular tachycardia or frequent ventricular premature beats [2]. The term cardiac memory was introduced by Rosenbaum MB et al in 1982 [3]. That seminal work showed that T wave changes may persist for days or weeks after the provoking stimulus which causes the change in activation sequence is discontinued. Supraventricular tachycardia can also evoke cardiac memory, particularly when the ventricular activation is irregular as in atrial fibrillation (AF) [2]. Cardiac memory manifests with a change of T wave vector, usually with T wave inversion. The T wave memorizes the QRS vector of the abnormal rhythm which preconditions the myocardium. The repolarization abnormalities usually manifests after the normalization of ventricular activation [3]. It is mentioned that cardiac memory actually starts with the abnormal ventricular activation, but is masked by the secondary repolarization abnormality of the abnormal activation [2]. The persistence of the cardiac memory depends on the duration of the abnormal activation. Persistent T wave inversion for hours to days after an episode of AF with fast ventricular rate makes us presume t...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: ECG / Electrophysiology Source Type: blogs