Patient Care Technician (PCT) AAH Practice Exam

What key feature distinguishes multifocal PVCs from unifocal PVCs?

1. Different shapes and sizes

2. Single source of origin

3. Higher heart rate

4. The presence of symptoms

The correct answer is: Different shapes and sizes

The distinction between multifocal premature ventricular contractions (PVCs) and unifocal PVCs primarily lies in the shape and size of the resulting contractions. In multifocal PVCs, multiple ectopic foci within the ventricles create a variety of PVCs, leading to different shapes and sizes on the electrocardiogram (ECG). This variability reflects that these PVCs originate from different locations in the ventricular myocardium. Conversely, unifocal PVCs arise from a single ectopic focus, leading to a uniform appearance in both shape and size on the ECG. This lack of variety is a clear characteristic that helps healthcare providers assess the underlying condition and potential risks associated with these contractions. Understanding this differentiation is crucial for patient assessment and management, as the presence of multifocal PVCs may indicate more significant cardiac irritability or underlying pathology than unifocal PVCs, which might be more benign.