Pacemakers

Question 1

How do pacemakers work

Answer 1

Deliver controlled electrical impulses to specific areas of the heart to restore normal electrical activity and improve heart function

Question 2

What do pacemakers consist of

Answer 2

Consist of a pulse generator(little pacemaker box) and pacing leads that carry electrical impulses to the relevant part of the heart

The box is implanted under the skin and the wires are implanted into the relevant chambers of the heart

Question 3

Where is a pacemaker most commonly implanted

Answer 3

Box is implanted under the skin most commonly in the left anterior chest wall or axilla

Question 4

What should be avoided in patients with pacemakers

Answer 4

MRI scans

Electrical interventions such as TENS and diathermy

Question 5

Indications for a pacemaker

Answer 5

Symptomatic bradycardias
Mobitz type 2 AV block
3rd degree heart block
Severe heart failure(biventricular pacemakers)
Hypertrophic obstructive cardiomyopathy(ICDs)

Question 6

What are implantable cardioverter defibrillators(ICDs)

Answer 6

Continually monitor the heart and apply a defibrillator shock to cardiovert the patient back in to sinus rhythm if they identify a shockable arrhythmia

Question 7

ECG changes with pacemakers

Answer 7

A line before each p-wave indicates a lead in the atria.

A line before each QRS complex indicates a lead in the ventricles. Therefore:

A line before either the P or QRS but not the other indicates a single-chamber pacemaker

A line before both the P and QRS indicates a dual-chamber pacemaker

Question 8

Indications for a temporary pacemaker

Answer 8

symptomatic/haemodynamically unstable bradycardia, not responding to atropine
post-ANTERIOR MI: type 2 or complete heart block*
trifascicular block prior to surgery