PVCs have a _______ QRS

• A. Narrow
• B. Wide
• C. Absent
• D. Normal

Answer: (B)

Premature ventricular contractions originate in the ventricular muscle itself, outside the normal His-Purkinje conduction pathway. Because the impulse starts in the ventricles and spreads through muscle tissue rather than the rapid conduction system, ventricular depolarization takes longer and proceeds in a nonstandard pattern. This makes the QRS complex broad and “bizarre”—typically wider than 120 ms and with an abnormal shape.

If the beat were coming from above the ventricles and conducted normally through the His-Purkinje system, the QRS would be narrow. An absent QRS would imply no ventricular depolarization, and a normal QRS would resemble the typical, ongoing rhythm. Hence, a PVC is characterized by a wide QRS.