Some supraventricular premature beats can produce broad QRS complexes. These premature supraventricular beats have to be distinguished from PVCs. 

The QRS complexes in PVCs come from a right or left bundle-branch block aberration. Generally, a P wave precedes the QRS complex with a prolonged PR interval. Often the P waves are hidden within the T waves. It may also produce a deformed T wave. The most common deformation is the “camel-like” appearance. 

Premature beats from the AV node are very rare. The P waves in this type are hidden within the QRS complex due to the retrograde direction caused by atrial activation. One can differentiate AV node-triggered premature beats from PVCs by identifying the QRS morphology in the precordial leads—PVCs display a bundle-branch block pattern.