Pacemakers Flashcards
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.
What are the 3 parts to the pacemaker?
- pulse generator
- lead(s)= wire
- patient
How is the pacemaker lead (wire) anchored to the wall of the heart so it doesn’t move?
- barbs (tines) or threaded wire that screws into the wall of the heart
What happens if a lead gets infected?
- it has to be removed
* really bad problem
What are the 2 methods of lead implantation?
- percutaneous (subclavian vein)
- cut-down (cephalic vein) via delta-pectoral groove
* can also go through internal or external jugular veins.
What is the technique called by which any catheter or wire in this case is placed?
- seldinger technique
Is pacemaker placement always done under fluoroscopy?
YES (in either cardiac cath lab or OR).
What should you think if a person who has a pacemaker, used to be able to do normal activities without getting SOB, but now they do?
- the pacemaker lead may have moved in the heart.
Why do we place the pacemaker so superficially?
- so we can read it via telemetry when we want to check its battery status or other functioning level.
What are some risks and complications of a pacemaker?
- arrhythmia
- bleeding
- infection
- lead displacement
- death
What is “capture”?
- when the pacemaker fires it’s electrical voltage and DEPOLARIZES the cardiac tissue.
What is “non-capture”?
- when the pacemaker fires and it’s electrical voltage does NOT depolarize the cardiac tissue.
- aka the heart and pacemaker are not listening to each other.
What is Twiddler’s syndrome?
- turning of the pacemaker in the chest due to pt “twiddling” with the pacemaker.
What are some other common lead failures?
- polyurethane bipolar leads may crack and metal ion oxidation occurs.
- pseudofracture (confirm with CXR).
What is the magnet used for on the side of a crash cart?
- for interrogating a pacemaker. When you place this over the pacemaker, you immediately convert it to a “FIXED” mode= set to factory standard (pacemaker’s intrinsic rate) at 65 BPM. So if you don’t see any pacemaker spikes, you know that the battery is dead, and if there is less than 65 BPM, then you know the battery is weak.
- PLACE THIS IMMEDIATELY DURING A CRASH to check the battery.
