Cardiac Memory - from Theory to Clinical Practice.

Cardiac memory (CM) is defined as changes in T wave polarity and vector that appear after cessation of a period of abnormal ventricular depolarization of various causes. The mechanisms responsible for CM development are initiation by local stretch, requiring myocardial contraction, followed by a cascade of intracellular signals that lead to a reduction in repolarization currents, especially Ito. In practice, CM is a frequently encountered ECG phenomenon, especially in patients with intermittent ventricular pacing, and knowledge of the ECG pattern of CM may help quick differential diagnosis from ischemia. While CM is most often a benign finding, in rare cases, association between CM and severe bradycardia or other factors for QT prolongation may be pro-arrhythmic and requires emergency care.