Advanced Patient Assessment Practice Exam

Which of the following is a hallmark of premature ventricular contraction (PVC)?

1. There is a P wave in front of the QRS complex

2. The T wave moves in the same direction as the QRS complex

3. The QRS complex is early but normal in appearance

4. The QRS complex is wider than normal

The correct answer is: The QRS complex is wider than normal

Premature ventricular contractions (PVCs) are characterized by a specific morphology of the QRS complex due to their origin in the ventricles rather than the atria. The hallmark feature of a PVC is that the QRS complex appears wider than normal. This is because PVCs occur when the heart's conduction system bypasses the usual pacemaking pathways and activates the ventricles in a manner that is different from normal conduction. As a result, the electrical signal takes longer to traverse the ventricles, leading to a wider QRS complex, often measuring 0.12 seconds or greater. The other characteristics listed are not specific to PVCs. Normally, a P wave precedes a QRS complex in standard sinus beats, but in the case of a PVC, there is typically no preceding P wave, as the ventricles are activated earlier than the next atrial impulse would occur. The T wave's direction can vary; while it might sometimes move in the same direction as the QRS complex, this is not a defining feature of PVCs. Therefore, the defining characteristic of PVCs remains the wide QRS complex, distinguishing them from other types of premature contractions or arrhythmias.