Pacemakers and AICD Lecture Powerpoint Flashcards
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Types of CIEDs (cardiovascular implantable electronic device) (4)
- pacemakers
- implantable cardioverter-defibrillator (ICD)
- implantable loop recorder
- external cardiac monitors
Pacemakers and what 2 things are they primarily used for
- Any device that delivers low dose electrical impulse or current to provide conduction to the heart, electrical signal causes cardiac contraction when myocardial electrical activity is too low or absent
- primarily used for heart block or hemodynamic instability
2 types of temporary pacemaker
- transcutaneous (most convenient but uncomfortable, often short term)
- transvenous (more reliable and comfortable)
3 parts of a pacemaker
- pulse generator (battery with 7-15 year lifespan)
- leads (sensors)
- electrodes (transmit impulse)
The 2 basic pacer functions
1) sensing a P wave
2) if no P wave, then fire
Asynchronous vs synchronous pacemaker
- Asynchronous (fixed) gives a beat regardless of the speed of the heart itself
- Synchronous (demand) only gives a shock when heart rate falls below 60bpm
Pacemaker appearance on EKG
Pacemaker spikes (vary in amplitude depending on lead) occur when no p wave is detected to trigger QRS, or right before QRS if a ventricular pacer
Indication for permanent pacemakers (its pretty cut and dry)
-symptoms with bradyarrhythmia with established correlation that have potential for progression to get worse
Contraindications for pacemakers
-none!
Leadless pacemaker
Small single ventricular pacemaking thru transvenous placement that combines the pulse generator and electrode into a single unit
Implantable cardioverter defibrillator and what are they used for
- delivers high voltage shock to interrupt or terminate ventricular arrhythmias (that a patient can certainly feel)
- Primarily used for rapid termination of Vfib or Vtach to increase chances of survival (prevent progression into asystole), considered first line treatment option
ATP (anti-tachycardic pacing)
Synchronized impulse that results in painless termination of ventricular tachycardia without having to undergo shock from defibrillation (still has that option as backup if it doesn’t work)
Cardioversion
Synchronized*** impulse delivered at peak of the R wave that is a painful shock to terminate Vtach
Defibrillation
Unynchronized shock delivered randomly during the cardiac cycle used to restore normal cardiac functioning, initial shocks delivered at lower energies reduces capacitor charge time, subsequent shocks are delivered at higher energies
Indications for an ICD (3)
- LVEF <35% due to prior MI
- Structural heart disease and spontaneous sustained Vtach
- Syncope of undetermined origin with clinically relevant, hemodynamically significant sustained vtach or vfib
