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 20-40 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 41-100 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.