Ventricular tachycardia(VT) is a fast, regular beating of the ventricles that may last for only a few seconds or much longer caused by abnormal electrical impulses that start in the ventricles. Often these are due to a problem with the electrical impulse traveling around a scar from a previous heart attack. VT can cause the ventricles to contract more than 200 beats a minute. Without prompt medical treatment, sustained ventricular tachycardia often worsens into ventricular fibrillation.
Attribution: Straight Talk Foundation