Pacemakers

Question 1

Indications for pacemakers

Answer 1

Symptomatic bradycardias
Mobitz Type 2 AV block
Third degree heart block
Severe heart failure (biventricular pacemakers)
Hypertrophic obstructive cardiomyopathy (ICDs)

Question 2

Types of pacemaker

Answer 2

Single chamber - leads in a single chamber (RA or RV)

Dual chamber - leads in both RA and RV
- Allows synchronisation of both atria and ventricles

Biventricular pacemaker

• Leads in RA, RV and LV
• Usually used in heart failure
• Also called cardiac resynchronisation therapy (CRT) pacemakers.

Question 3

What is an ICD?

Answer 3

Implantable Cardioverter Defibrillators

They continually monitor the heart and apply a defibrillator shock to cardiovert back into sinus rhythm if they identify a shockable arrhythmia.

Question 4

What ECG findings are seen in patients with pacemakers?

Answer 4

Pacing spikes before the P waves and/or the QRS complexes (depending on if there are leads in the atria, ventricles or both)