The premature ventricular complex as a diagnostic aid.

Premature ventricular complexes (PVCs) can provide clues to the physical or electrocardiographic diagnosis through the associated compensatory pause, the break in the regularity of the rhythm, or the morphology of the PVC itself. A PVC may allow visualization of the P wave or of atrial flutter waves that would otherwise be obscured in the electrocardiogram. It can also be useful in distinguishing an S3 gallop from an S4 gallop. The compensatory pause that follows a PVC may allow normal conduction of the next QRS complex in a patient with a rate-dependent intraventricular conduction defect, and this normalized QRS complex may contain important diagnostic findings. A PVC can also reveal a myocardial infarct pattern when the sinus complex fails to do so. Although the need to treat PVCs is currently being de-emphasized, their diagnostic utility should not be overlooked.