What describes a premature ventricular contraction?

A premature ventricular contraction (PVC) is characterized as an extra heartbeat that originates from the ventricles, rather than the typical electrical impulse generated by the heart's natural pacemaker, the sinus node. This abnormal impulse interrupts the regular rhythm of the heart, leading to additional contractions that can occur before the next expected heartbeat.

When a PVC occurs, it is usually due to an ectopic focus within the ventricle that initiates an impulse prematurely. This results in the ventricles contracting earlier than they normally would, hence the term "premature." The electrical activity is different from normal sinus rhythm, which originates in the atria. Because PVCs originate in the ventricles, they can lead to a distinct waveform on an electrocardiogram (ECG), typically displayed as a wide and bizarre-looking QRS complex.

Understanding the nature of PVCs is crucial in interventional radiology and cardiovascular medicine, as they can indicate underlying cardiac issues and inform the appropriate management of the patient.