Regarding PVC QRS morphology, which statement is true?

• A. It is always narrow
• B. It matches normal QRS in origin
• C. It is wide in most leads
• D. It occurs only in lead II

Answer: (C)

The key idea is that a premature ventricular contraction originates in the ventricular muscle rather than the normal His–Purkinje system, so its depolarization spreads through the ventricles more slowly. That slower, cell-to-cell spread broadens the QRS complex, giving a wide QRS during the PVC. This broad QRS is typically seen across most ECG leads, often with a morphology resembling a bundle-branch block pattern, and usually longer than 120 ms. Because the impulse starts in the ventricles, the QRS does not match a normal, sinus-origin QRS in timing or pattern, and it isn’t limited to a single lead like lead II. It can appear in multiple leads depending on the origin within the ventricle and the heart’s axis. So, the statement that the PVC QRS is wide in most leads best captures the key characteristic.