<unk> s <unk> s), also known as atrial<unk>  complexes (APC) or atrial<unk>  beats (APB), are a common cardiac dysrhythmia characterized by<unk>  heartbeats originating in the atria. While the sinoatrial node typically regulates the heartbeat during normal sinus rhythm,<unk> s occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a<unk>  heartbeat, in contrast to escape beats, in which the normal sinoatrial node fails, leaving a non-nodal<unk> emaker to initiate a late beat. The exact cause of<unk> s is unclear; while several predisposing conditions exist, single<unk> s commonly occur in healthy young and elderly people. Elderly people that get<unk> s usually don't need any further attention besides follow ups due to unclear evidence.<unk> s are often completely asymptomatic and may be noted only with Holter monitoring, but occasionally they can be perceived as a skipped beat or a jolt in the chest. In most cases, no treatment other than reassurance is needed for<unk> s, although medications such as beta blockers can reduce the frequency of symptomatic<unk> s.
Premature atrial contraction
Premature ventricular contraction
Benign early repolarization
Wandering atrial pacemaker
Premature junctional contraction
AV nodal reentrant tachycardia
Ventricular escape beat
Ectopic pacemaker