Premature ventricular contractions are notable for the presence of a premature broad QRS complex that is not preceded by a P wave. The absence of a P wave means that the ventricles are the origin of the impulses. When an impulse comes from the interventricular septum, the QRS complex is broad and small with a slightly altered configuration.

Bigeminy is a term used to refer to a PVC that occurs right after a normal beat. Trigeminy refers to a PVC that occurs after two normal beats. Quadrigeminy refers to a normal beat followed by three consecutive PVCs.

Premature Ventricular Contractions in Bigeminy ECG ⁵¹

Premature Ventricular Contractions in Quadrigeminy ⁵²

Sometimes a pattern of PVCs is designated as a 2:1 extrasystole wherein there is the occurrence of a PVC after two normal beats. The 3:1 extrasystole refers to a PVC occurring after three normal beats.

The patient’s hemodynamics are more affected, and the heart disease is more advanced when trigeminy or quadrigeminy is present as opposed to 2:1 or 3:1 extrasystole.

Related Video – ECG Rhythm Review – PVCs

Two consecutive PVCs are called a couplet. Three consecutive premature beats are called a triplet.

Premature Ventricular Contractions in a Couplet ⁵³

Ventricular tachycardia is present when three or more PVCs are formed. A run of four or more is called a “salvo of PVCs” in some sources.

Patient With Short Bursts of Consecutive Premature Ventricular Contractions ECG ⁵⁴

Related Video – One Quick Question: How Can I Remember the PVCs?