Premature ventricular contraction
（重定向自Multifocal ventricular premature beats）
A premature ventricular contraction (PVC) — also known as a premature ventricular complex, ventricular premature contraction (or complex or complexes) (VPC), ventricular premature beat (VPB), or ventricular extrasystole (VES) — is a relatively common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node, the normal heartbeat initiator. The electrical events of the heart detected by the electrocardiogram (ECG) allow a PVC to be easily distinguished from a normal heart beat. Although a PVC can be a sign of decreased oxygenation to the heart muscle, often PVCs are benign and may even be found in otherwise healthy hearts.