Electrical remodeling is a persistent change in the electrophysiological properties of myocardium in response to a change in rate or activation sequence. Although it is well established that alterations in heart rate or activation sequence induce electrical remodeling in atria, heart rate and activation sequence-induced electrical remodeling in ventricle are poorly understood. This research shows that persistent changes in ventricular repolarization can be induced by surprisingly short periods of altered rate or activation sequence, and the nature of ventricular electrical remodeling induced by these two protocols is different. This research suggests a novel mechanism for triggering electrical remodeling in ventricle.