Final answer:
Premature ventricular contractions (PVCs) on an ECG are indicated by wide QRS complexes and an absence of P waves preceding them. The wide QRS complex suggests an abnormal ventricular origin of the electrical impulse, and the lack of P waves indicates it did not start from the sinoatrial node.
Step-by-step explanation:
When monitoring a client's ECG rhythm for premature ventricular contractions (PVCs), the characteristics that indicate PVCs are wide QRS complexes and no P waves preceding them. In a normal ECG tracing, the small P wave represents the depolarization of the atria, followed by a large QRS complex which represents the depolarization of the ventricles. In the case of PVCs, the QRS complex is wider because the electrical impulse originates in the ventricles and spreads through them in an abnormal way, which is slower than the normal route through the conduction system. Additionally, the impulse does not originate in the sinoatrial node, so there is no associated P wave.
Therefore, the correct answer to the question 'The nurse cares for a client at risk for premature ventricular contractions (PVC). When monitoring the client's ECG rhythm, what characteristics indicate PVC?' is D. Wide QRS complexes and no P waves.