A comprehensive review of all the latest developments in cardiac electrophysiology, focusing on both the clinical and experimental aspects of ventricular repolarization, including newly discovered clinical repolarization syndromes, electrocardiographic phenomena, and their correlation with the most recent advances in basic science. The authors illuminate the basic electrophysiologic, molecular, and pharmacologic mechanisms underlying ventricular repolarization, relate them to specific disease conditions, and examine the future of antiarrhythmic drug development based on both molecular and electrophysiological properties. They also fully review the clinical presentation and management of specific cardiac repolarization conditions.