A nurse is caring for a client with a ventricular pacemaker who is on cardiac monitor monitoring. The nurse understands that the pacemaker is functioning properly when which of the following appears on the monitor strip?

A ventricular pacemaker delivers an electrical impulse to the ventricle to stimulate a heartbeat when the heart's intrinsic rate falls below the programmed threshold. On a cardiac monitor strip, proper ventricular pacemaker function is confirmed by the presence of a pacemaker spike immediately before each wide QRS complex, because the spike represents the electrical artifact from the pacemaker firing, and the subsequent broad QRS reflects ventricular depolarization in response to that stimulus. The spike-before-QRS sequence confirms that the pacemaker is both sensing and capturing correctly. Pacemaker spikes after each QRS complex would indicate the device is firing after the heart has already depolarized on its own, which would represent a sensing failure or an asynchronous mode misinterpretation. Pacemaker spikes before each P wave would describe an atrial pacemaker, not a ventricular one, since the P wave represents atrial depolarization. Pacemaker spikes associated with T waves would indicate firing during the vulnerable period of repolarization, which is dangerous and would represent a malfunction rather than normal operation.