Which statement distinguishes unifocal and multifocal PVCs?

• A. Unifocal PVCs Have Identical Morphology Across Beats; Multifocal PVCs Have Multiple Morphologies
• B. Unifocal PVCs Have Different Morphologies; Multifocal PVCs Have Identical Morphologies
• C. Unifocal PVCs Appear In Multiple Leads; Multifocal Appear In A Single Lead
• D. Unifocal Always Produce A Wide QRS; Multifocal Sometimes Narrow

Answer: (A)

The essential idea is that the number of abnormal ventricular origins shows up in the shape of the PVCs. If all the PVCs look the same from beat to beat, they come from a single ectopic focus in the ventricle—that’s unifocal. If you see several different shapes, originating from different spots, there are multiple foci—multifocal. That’s why the statement that unifocal PVCs have identical morphology across beats and multifocal PVCs have multiple morphologies is the best description. The other options mix up features that aren’t reliable indicators of focality—such as which leads show the PVCs or the QRS width—which is not the defining difference.