Which premature ventricular complex morphology involves multiple ventricular foci and typically requires monitoring?

• A. Unifocal premature ventricular complexes
• B. Bigeminy
• C. Couplets
• D. Multifocal premature ventricular complexes

Answer: (D)

Premature ventricular complexes reveal where in the ventricle they originate. If every PVC looks the same on the ECG, they come from a single ventricular focus—unifocal. If the PVCs have several different shapes, they come from more than one ventricular location—multifocal. Multifocal PVCs indicate greater ventricular irritability and are typically monitored because they can signal evolving instability or underlying issues such as ischemia, electrolyte abnormalities, hypoxia, or drug toxicity, and may portend progression to more dangerous rhythms.

The other patterns describe rhythm arrangement rather than the origin of the ectopic beats. Bigeminy means a PVC follows every normal beat, and couplets are two PVCs in a row; these patterns can occur with either unifocal or multifocal PVCs, but they don’t specify multiple foci.