The patient has a permanent pacemaker in place with a demand rate set at 60 beats/min.The cardiac monitor is showing a heart rate of 44 beats/min with no pacemaker spikes.The nurse realizes this as:
A) normal pacemaker function.
B) failure to capture.
C) failure to pace.
D) failure to sense.

Question

Quizplus · Accepted Answer

Failure to pace or fire occurs when the pacemaker fails to initiate an electrical stimulus when it should fire.The problem is noted by absence of pacer spikes on the rhythm strip.Causes of failure to pace include battery or pulse generator failure,fracture or displacement of a pacemaker wire,or loose connections.This is not normal pacemaker function.When the pacemaker generates an electrical impulse (pacer spike)and no depolarization is noted,it is described a failure to capture.On the ECG,a pacer spike is noted,but it is not followed by a P wave (atrial pacemaker)or a QRS complex (ventricular pacemaker).Common causes of failure to capture include output (milliamperes)set too low,or displacement of the pacing lead wire from the myocardium (transvenous or epicardial leads).Other causes of failure to capture include battery failure,fracture of the pacemaker wire,or increased pacing threshold as a result of medication or electrolyte imbalance.When the pacemaker does not sense the patient's own cardiac rhythm and initiates an electrical impulse,it is called failure to sense.Failure to sense manifests as pacer spikes that fall too closely to the patient's own rhythm,earlier than the programmed rate.The most common cause is displacement of the pacemaker electrode wire.

The Patient Has a Permanent Pacemaker in Place with a Demand