Which of the following is a typical feature of a PVC on ECG?

• A. Wide QRS, no P wave.
• B. Narrow QRS and P wave before every beat.
• C. Regular rhythm with normal P waves.
• D. Normal QRS with ST elevation.

Answer: (A)

Premature ventricular contractions are ectopic beats that start in the ventricles, not in the atria. Because the impulse originates in the ventricular muscle, conduction takes a slower, abnormal path, so the depolarization wave spreads through the ventricles in a way that makes the QRS broad and ugly in shape. The ventricle-driven beat doesn’t have a preceding atrial depolarization, so there’s usually no P wave before that beat. That combination—an early beat with a wide QRS and no preceding P wave—is the classic hallmark of a PVC.

In contrast, a narrow QRS with a P wave before every beat describes a normal sinus beat, and a regular rhythm with normal P waves also fits normal atrial-ventricular conduction. A normal QRS with ST elevation points to a different issue, such as acute ischemia or injury, not a PVC.