Action potential in cardiomyocytes The action potential in typical cardiomyocytes is composed of 5 phases (0-4), beginning and ending with phase 4. Phase 4: The resting phase Phase 0: Depolarization Phase 1: Early repolarization Phase 2: The plateau phase Phase 3: Repolarization #Pathophysiology #Cardiac #ActionPotential #Myocytes #Phases #Depolarization #Repolarization