Pacemaker Flashcards
What is Failure to pace?
A pacemaker malfunction. Failure of the pacemaker; recognized by missing pacemaker spikes on the ECG
What is failure to capture?
A pacemaker malfunction. The heart does not respond to the pacer stimulus; recognized by pacer spikes on the ECG that are not followed by a QRS
What is Undersensing?
A pacemaker malfunction. The pacemaker is not “seeing” the patient’s intrinsic heart rhythm; recognized by pacer spikes within the intrinsic ECG waveforms
What is oversensing?
A pacemaker malfunction. The pacemaker is “seeing” too much of the patient’s intrinsic rhythm, assuming all the waveforms are QRS complexes; recognized by a rate that is slower than the set rate and missing pacer spikes
VOO
Asynchronous ventricular pacer
AAI
Atrium is sensed and paced
VVI
Ventricle is sensed and paced
DDD
Atria and ventricle are sensed and paced
What is a single-chamber pacemaker?
Pacing achieved using only one pacing lead in either the atrium or ventricle
One pacing spike visible preceding either the P wave or the QRS
What is a dual-chamber pacemaker?
Pacing achieved using two or more pacing leads placed in the atrium and the ventricle to stimulate atrial and ventricular depolarization
Two pacing spikes visible; one preceding the P wave and one preceding the QRS
What is a Fixed-Rate pacemaker?
Delivers a stimulus at a set rate regardless of the patient’s intrinsic heart rhythm;
Also known as asynchronous pacing
Can compete with the patient’s intrinsic rhythm and cause an arrhythmia. This mode is not safe for long periods of time.
What is a Demand pacemaker?
Delivers a stimulus when needed based on the patient’s intrinsic heart rhythm
Synchronous or non competitive
Why should gloves always be worn while handling pacer leads
to prevent the occurrence of micro shock which has the potential to cause an arrhythmia
If a pacing spike is seen on an ECG preceding a P-wave, what is the rhythm?
Atrial paced rhythm
A spike is seen preceding wide QRS complexes, what is this rhythm?
Ventricular paced rhythm
What are some reasons for a failure to pace?
Dead battery
Disconnection/lost contact with myocardium
Fractured lead
Pacemaker turned off
Electromagnetic interference
What is failure to capture?
Inability of pacemaker stimulus to depolarize the myocardium
Recognized on ECG by visible pacer spikes not followed by P wave or QRS complex
What is a failure to pace?
-Aka failure to fire
-Pacemaker fails to deliver an electrical stimulus at its programmed time
-Indicated on ECG rhythm as absence of pacer spike
What are some causes of failure to capture?
-voltage insufficient
-lead malpositiomed
-electrolyte imbalance or other cause increasing stimulation threshold
What is the treatment/intervention for a failure to capture?
Slowly increase mA until both electrical and mechanical capture achieved, check pacer wires and connections, turn patient to left side (only relevant if it is a transvenous pacer), treat underlying cause
What is undersensing?
The pacemaker is not “seeing” the patient’s intrinsic heart rhythm; recognized by pacer spikes within the intrinsic ECG waveforms
What causes undersensing?
The sensitivity is insufficient; it is not “seeing enough”
What is the intervention for undersensing?
Slowly increase sensitivity settings (decrease mV) until sensing and pacing appropriately
What is oversensing?
The pacemaker is “seeing” too much of the patient’s intrinsic rhythm, assuming all the waveforms are QRS complexes; recognized by a rate that is slower than the set rate and missing pacer spikes
What are the causes of oversensing?
The sensitivity is too high; the pacer is “seeing too much”
How is oversensing treated??
Slowly decrease the sensitivity (increase mV towards asynchronous) until sensing and pacing appropriately
What are the nursing considerations for pacemakers in critical care?
always assume a patient has a temporary pacemaker until proven otherwise.
If the pacer malfunctions, assess and treat the patient first (call a code, CPR, etc.) and prioritize pacemaker troubleshooting second
What are the additional assessment parts for a patient with pacemaker?
When a patient is being paced using transvenous or epicardial methods, there are always additional assessment that the nursing must complete as part of the head-to-toe and ongoing assessment in critical care:
Assess the rhythm for signs of failure to capture or sensing malfunctions; continuously monitor for new signs of malfunction
Assess for mechanical capture
Ensure there are extra batteries, cords, and back-up pacer pack in the room
Check the pacemaker insertion site, the wires, connections, and pacer battery life
Assess the pacer mode, set rate, the output (mA), and the sensitivity (mV) and document
Secure out of reach of the patient and to prevent from falling or dislodging
If the pacer malfunctions, assess and treat the patient first (call a code, CPR, etc.) and prioritize pacemaker troubleshooting second
