A term used to describe any variation from the normal pattern of the heartbeat. There are several kinds of arrythmias including asystole, atrial fibrillation, atrioventricular block, premature ventricular contraction and sinoatrial block.
Abnormal heart beats...any disturbance in the cadence or regularity of the heart rythm. Some arrythmias are not dangerous, while some can cause stoppage of the heart contractions and death.