What defines ventricular tachycardia?

Ventricular tachycardia (VT) is defined specifically as a condition where there are three or more consecutive premature ventricular contractions (PVCs). This definition is based on the understanding that VT is a rapid heart rhythm originating from the ventricles, characterized by the presence of these three or more PVCs occurring in succession. This rapid rhythm can be sustained over a period of time and may lead to hemodynamic instability, which makes early recognition and appropriate intervention crucial.

The choice indicating two PVCs in a row does not meet the clinical criteria set for ventricular tachycardia, since it does not satisfy the minimum threshold. Similarly, while four or more PVCs could indicate a more sustained episode, they are not necessary to define VT. Additionally, the reference to continuous PVCs for 30 seconds describes a different classification of sustained ventricular tachycardia, rather than the initial definition. Therefore, the defining standard is based on the presence of three or more PVCs consecutively, marking the onset of ventricular tachycardia.