Pacemakers

Question 1

Indications for Pacing

Answer 1

• symptomatic bradycardia
• heart blocks 2nd degree type II and third degree
• anti-tachycardia-pacing override a rapid rate
• cardiac rhythm resynchronization therapy (CRT)- the bi-ventricular pacing restores ventricular synchrony to improve quality of life/ symptoms of heart failure

Question 2

Temporary Pacemakers

Answer 2

• Transvenous pacemaker
• Epicardial pacing
• Transcutaneous pacing

Question 3

Indications for Transcutaneous Pacing

Answer 3

• significant bradycardia unresponsive to atropine therapy or when atropine is not immediately available for indicated
• “bridge” until transvenous pacing can be accomplished or cause of the bradycardia is reversed
• drug overdose
• hyperkalemia

Question 4

Transcutaneous Pacing

Answer 4

• pacing pads are applied to the outside of the patients chest (usually in emergency)
• will see spike on the monitor and rhythm strip
• always check for a FEMORAL pulse
• always look for QRS complex after spike

Question 5

Pacemaker Function: 3 Components

Answer 5

• Pacing
• Capture
• Sensing

Question 6

Pacing

Answer 6

-Evidence of an artifact or spike
>Types of pacing: 
-Atrial pacing
-Ventricular pacing
-AV pacing (both)
-Bi pacing

Question 7

Atrial Pacing

Answer 7

• pacing electrode placed in R atrium

- may be used when SA node is diseased or damaged but conduction through AV junction and ventricles is normal

Question 8

Capture

Answer 8

-the successful conduction of the pacemaker artificial impulse resulting in depolarization of either or both chambers
>Atrial capture: pacemaker spike followed by a P wave
>Ventricular capture: pacemaker spike followed by a wide QRS (impulse coming directly from ventricles)
>AV capture: pacing spike is seen before P wave and QRS complex

Question 9

Sensing

Answer 9

• the pacemaker prevents itself from firing
• it detects the patients own beat or rhythm
• there should be an absence of pacemaker spikes during the patients own rhythm
• demand pacing: when the pacemaker spike is sensing correctly; the pacemaker is firing only when needed

Question 10

Failure to pace

Answer 10

-“failure to fire”
-artificial pacemaker fails to deliver an electrical stimulus at its programmed time
-absence of a pacemaker spike and a return of the underlying rhythm for which pacing was initiated
>Intervention: pacemaker needs to be interrogated; application of transcutaneous pacemaker until permanent pacemaker is fixed

Question 11

Failure to Capture

Answer 11

-visible pacemaker spike not followed by P waves (if electrodes in atrium) or QRS complexes (if electrode in R ventricle)
>Intervention: pacemaker needs to be interrogated immediately; application of transcutaneous pacemaker until permanent pacemaker is fixed

Question 12

Failure to Sense

Answer 12

-the pacemaker does not sense the patient’s own rhythm
-the pacemaker continues to fire impulses
>Intervention: pacemaker needs to be interrogated immediately; application of transcutaneous pacemaker until permanent pacemaker is fixed; call a code, start CPR, defibrillate