Where is the pacemaker battery placed?
- beneath the skin just above the pectorals major of the left chest wall.
To what is the pacemaker battery connected?
- a wire that goes into the subclavian vein, into the superior vena cava, and into both the right atrial wall and tip of the right ventricle.
What are the indications for a pacemaker?
- heart failure (New York Heart Association class III or IV).
- sever systolic dysfunction (left ventricular ejection fraction less than 35%).
- intraventricular conduction delay (QRS greater than 120 ms).
What are the 3 different types of pacemakers?
- one wire into the right ventricular apex
- AV Sequential Pacer= dual wires into both right atria and right ventricle. It can pace the atria, and if a delay occurs, then pace the ventricles as needed.
- 3 wires for patients with severe heart failure (3rd wire goes in vein behind left ventricle)
How long does the pacemaker placement procedure take?
1-3 hours under light sedation.
Will the pacemaker set off airport security machines?
YES
Will the pacemaker prevent you from getting an MRI?
in the old machines, yes. However, the newer MRIs allow you to have them.
How long do pacemakers last?
6-10 years, but followed by cardiologist every 3-6 months.
Current indications for placement of a cardiac pacemaker include which of the following?
A. sinus sick syndrome with bradyarrhythmias
B. Mobitz Type II AV block
C. Carotid sinus massage
D. symptomatic bifascicular or trifascicular blocks
E. all of the above
E. All of the above
What is cardiac resynchronization therapy (CRT)?
cardiac pacemaker
What will you see on EKG with an atrial pacemaker?
- little spikes occurring just before the P wave, indicating depolarization of the cells of the atria.
- narrowed QRS
- looks a lot like sinus rhythm
At what rate are atrial pacemakers normally set?
60-100
What will EKG show with an AV sequential pacemaker?
- regular rhythm
- P wave present or none
- wide QRS (width greater than 120 ms)
- 2 pacer spikes (one for atria and one for ventricles)
- makes sense that QRS is wider bc it is taking a different but longer path of electrical conduction to depolarize the ventricles.
What will EKG show with a ventricular only pacemaker?
- regular rhythm
- ABSENT P waves (bc no atrial depolarization)
- widened QRS (greater than 120 ms)
- pacer spike immediately before QRS
What is a demand pacemaker?
- fires only when the heart’s own automaticity foci fail to fire.
How should a pacemaker be viewed in the heart?
as an ectopic automaticity foci
What types of problems may you have with your cardiac conduction system?
- ischemic heart disease (ex. in LAD, leading to loss of conduction through the septum).
Would you want thyroid studies before placing a cardiac pacemaker?
YES
What are the AHA approved indications for pacemaker placement?
- post AV junction ablation
- first degree A-V block
- neurocardiogenic syncope
- hypertrophic obstructive cardiomyopathy
- dilated cardiomyopathy
- sick sinus syndrome (Lev’s disease)
- 3rd degree heart block
How do you treat sick sinus syndrome?
- suppress the fast rhythm (with BETA BLOCKADE) and augment the slow rhythm (with a PACEMAKER).
How are pacemakers designated for position I and II?
- Position I= the chamber that it PACES.
- Position II= the chamber that it SENSES:
- O= none
- A= Atrium
- V= Ventricle
- D= Dual (A+V)
(ex. V, V for pacing and sensing of the ventricles).
What does position III mean on a pacemaker?
- RESPONSE to SENSING (aka mode of operation).
- O= none
- T= Triggered
- I= Inhibited
- D= Dual (T+I)
What is the 2 most commonly seen pacemakers?
- VVI= paces the ventricles, senses the ventricles, and inhibits itself when it senses a beat.
- DDD= paces both chambers, senses both chambers, and can either turn itself on or turn itself off, based on what it receives.
What is the advantage of pacing the atria and the ventricles (DDD)?
- you get 15% more CO by pacing the atria as well.
