 A premature ventricular complex (PVC) arises from an irritable table site within either ventricle.  A full compensatory pause often follows a PVC.  A fusion beat is a result of an electrical impulse from a supraventricular site (such as the SA node) discharging at the same time as an ectopic site in the ventricles. PVC

 Pairs (couplets): two sequential PVCs  “Runs” or “Bursts”: 3 or more PVCs in a row  Bigeminal PVCs: every other beat is a PVC  Trigeminal PVCs: every third beat is a PVC  Quadrigeminal PVCs: every fourth beat is a PVC

 Uniform & Multiformed PVCs › PVCs that look alike in the same lead and begin from the same anatomic site are called uniform PVCs. › PVCs that look different from one another in the same lead are called multiform PVCs.

 Interpolated PVCs › An interpolated PVC doesn’t have a full compensatory pause.  R-on-T PVCs › R-on-T PVCs occur when the R wave of a PVC falls on the T wave of the preceding beat.  Paired PVCs (Couplets) › Two PVCs in a row are called a couplet or paired PVC.

 A ventricular escape beat occurs after a pause in which a supraventricular pacemaker failed to fire.  A ventricular escape or idioventricular rhythm (IVR) exists when 3 or more ventricular escape beats occur in a row at a rate of bpm.  If the patient is not breathing & they have no pulse despire the appearance of organized electrical activity on the cardiac monitor, a clinical situation called pulseless electrical activity (PEA) exists.

 An accelerated idioventricular rhythm (AIVR) exists when 3 or more ventricular beats occur in a row at a rate of bpm.

 Ventricular tachycardia exists when 3 or more PVCs occur in a row at a rate greater than 100 bpm. Notice HR

 Monomorphic VT › When the QRS complexes of VT are of the same shape & amplitude, the rhythm is called monomorphic VT.

 Polymorphic VT › When QRS complexes of VT vary in shape and amplitude from beat to beat, the rhythm is called polymorphic VT. › Polymorphic VT that occurs in the presence of a long QT interval is called torsades de pointes (TdP). › Long QT syndrome is an abnormality of the heart’s electrical system.

 Ventricular fibrillation is a chaotic rhythm that begins in the ventricles. There is no organized depolarization of the ventricles.

 Defibrillation is the therapeutic delivery of an unsynchronized electrical current through the myocardium over a very brief period to terminate a cardiac dysrhythmia.

 Asystole is the total absence of ventricular electrical activity.