Very frequent PVCs can lead to which rhythm change?

• A. Atrial fibrillation
• B. Sinus bradycardia
• C. Runs of VT
• D. Normal sinus rhythm

Answer: (C)

Very frequent PVCs show ventricular ectopy so often that the ventricles can depolarize in a rapid, organized way. When three or more consecutive PVCs occur, this is called a run of ventricular tachycardia. It happens because the ectopic ventricular focus or a reentry circuit sustains rapid ventricular firing, producing a fast, wide-complex rhythm on the ECG.

This differs from atrial fibrillation, which is an irregular atrial rhythm with an irregular ventricular response; from sinus bradycardia, which is a slow but otherwise normal-appearing sinus rhythm; and from normal sinus rhythm, which would not display a rapid sequence of wide QRS complexes.