A<unk>  is a self-generated electrical discharge initiated by and causing contraction of the ventricles of the heart.  It is a heart rhythm finding discovered on EKG, that indicates the normal electrical conduction system of the heart is disrupted or performing inadequately i.e failure of the SA node and AV node to generate an impulse.  The<unk>  follows a long pause in ventricular rhythm and acts to prevent cardiac arrest.
Ventricular escape beat
Isorhythmic A-V dissociation
Fascicular VT
Wide complex tachycardia
Sinoatrial arrest
Junctional rhythm
Idioventricular rhythm
Mahaim type preexcitation