Pacemakers and Defibrillators Flashcards
Define CRMD
Cardiac Rhythm Management Device
Where are pacing leads placed within the heart?
Right atrium and right ventricle
What are indications for a pacemaker? (5)
- Sinus node disease–failure to form impulse
- AV node disease–failure to conduct impulse
- Long QT syndrome
- Hypertrophic obstructive cardiomyopathy
- Dilated cardiomyopathy
Note: Most pts fall into first 2 indications listed.
What conditions require 100% ventricular pacing?
hypertrophic obstructive cardiomyopathy
dilated cardiomyopathy
Note: Short AV delays (120-150msec) are programmed.
What are 3 pacemaker classification systems?
NASPE - North American Society of Pacing and Electrophysiology
BPEG - British Pacing and Electrophysiology Group
NBG - Naspe and Bpeg Generic
NBG classification of Bradycardia Support Pacemakers
What does each number represent?
Position 1: Pacing chamber
2: Chamber sensed
3: Responses to sensing (directly tied to position 2, if no value for 2, no value for 3 is possible)
4: Programmable functions
5: Anti-tachycardia functions
Note: Directly from NBG Code website because notes don’t make sense o/w.
What are modes of response to sensing?
I (inhibited) – withhold a pacemaker output in response to a sensed event.
D (dual) choices: inhibit PM, track the sensed event, inhibit output on sensed channel and trigger output to maintain synchrony
T (triggered) – produces output spikes coincident with the sensed signal (diagnostic only)
What are programmability functions?
R (rate responsive) – device is capable of a rate responsive function
C (communicating) – capable of transmitting or receiving data for informational or programming purposes.
M (multi-programmable) – device can be programmed in more than 3 parameters: Rate, sensing, output, refractory periods, mode, hysteresis (means history vs. current condition essentially)
P (simple programmable) – limited to 3 or fewer programmable parameters
O (none) – not programmable
What are anti-tachycardia functions?
P (paced) – pace the patient out of tachycardia
S (shocks) – deliver a defibrillating shock
D (dual – paced and shocks)
O (none)
Note: This is position 5.
For anti-tachycardia functions, most bradycardia devices are ___ and most ICDs are ____.
O, none
D, dual
What are asynchronous modes?
AOO – Fixed rate atrial pacing
VOO – Fixed rate ventricular pacing
DOO – Fixed rate AV sequential pacing, paces both atria and ventricles
Note: When a magnet is placed on the PM, asynchronous mode initiates and goes into a fixed pacing mode despite heart activity.
What is DDD mode?
Paces Atrium and Ventricles
Senses Atrium and Ventricular signals
Sensed atrial signal will cause the device to inhibit the atrial output, a timer starts that will cause a triggered ventricular output after a certain interval but, if the patient has an R wave during the triggering interval the ventricular output will be inhibited.
In the event of high atrial rates and heart block, DDI will most resemble what pacemaker setting?
VVI
What is AAI mode?
atrial-inhibited pacing
What is VVI mode?
ventricular inhibited pacing
What is VAT mode?
Atrial-triggered, ventricular pacing
What is VDD mode?
It is atrial triggered, ventricular inhibited pacing
What is DVI mode?
Dual-sequential pacing, ventricular inhibited.
What is DDI mode?
Dual-chamber, sequential inhibited pacing
Note: Does not trigger where a signal is sensed.
The implantable PM is placed in the pectoral region. The lead enters the ___________ immediately superior to the ______________________.
right external jugular vein
medial end of the clavicle
Transvenous pacing leads may be:
unipolar
bipolar
Note: Leads are placed endocardially.
What is depicted here?
Epicardial and unipolar PM
Lead A is a space if B should fail.
Lead B is connected to the generator.
What is AOO mode?
asynchronous pacing of atria–regardless of atrial activity
What PM mode would generate this ECG?
AAI
What PM mode would generate this ECG?
What PM mode would generate this ECG?
What PM mode?
What PM mode?
What PM mode?
What PM mode?
What PM mode?
What PM mode?
What PM mode resembles unifocal PVCs?
VOO
What is depicted?
atrial pacing
What is depicted?
AV sequential pacing
What is depicted?
failure to capture
What are the types of endocardial leads(transvenous)?
active fixation –metal screw-in
passive fixation –rubber fins or tines
What are the types of epicardial leads?
screw-in
sew-on
What are the different polarities of pacing leads?
unipolar –highest reliability
bipolar –improved rejection for better sensing
multipolar –special purpose leads
What are the different lead tips?
steroid eluting –believed that scarring is decreased
non-steroid eluting
carbon–least scarring but tend to take more current
What is depicted?
PA catheter with bipolar ventricular pacing wire
What is depicted?
Label
Pacing Swan-Ganz
What is depicted?
Where is the pacing probe located?
Chandler V-pacing probe
19 cm from distal end
What rate modulation sensors are currently approved in the US?
Vibration sensor
Motion sensor
Minute ventilation (bioimpedance sensor)
RV pressure
What sensors are very sensitive to stray electromagnetic interference where pts have been inappropriately treated for pm driven tachycardias?
Minute ventilation sensors
What setting is recommended for the perioperative period for PMs?
Rate modulation set to “OFF” to prevent confusion of intrinsic tachycardia with PM induced tachycardia.
Which rate modulation sensors have little perioperative issues?
RV pressure sensors
What are activity sensors that adjust heart rate to activity?
Motion sensor
Minute ventilation sensor
What is an example of pacemaker magnet behavior?
Asynchronous “high-rate” pacing
What should you do if performing upper body surgery with PM pt?
What should you do if performing lower body surgery with PM pt?
Set PM to asynchronous activity if not emergent.
If lower body surgery, PM should be OK as is.
Which type of cautery is better used with a PM patient?
Bipolar is safer (current passes between forceps) than monopolar since this current has to pass through the patient.
What situations require PM reprogramming?
Any rate responsive device
Special pacing indication (eg. hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy, pediatric patients)
Major surgery in chest or abdomen
Special procedures like:
- immersion lithotripsy
- transurethral resection
- hysteroscopy
- electroconvulsive therapy
- MRI
- Sux use
What does the horizontal line after shock delivery show?
The cardiograph was blocked or disconnected for its protection during the period of shock.
Identify the defibrillation positions.
A. Correct positioning in a patient with a permanent PM. Also considered the best position for paddles. Less current needed.
B. Placement recommended by the American Heart Association. Note: Place below sternal notch.
What is synchronized defibrillation also known as?
cardioversion
When should a synchonized defibrillation take place?
What point is considered the vulnerable period?
M designates when a shock should be applied in the cardiac cycle.
VP is the vulnerable period and shock delivery may result in ventricular fibrillation.
Label
In other words:
- Shock chamber
- Anti-tachycardia pacing
- Tachycardia sensor
- Anti-bradycardia pacing
What is depicted?
Pacemaker and defibrillator
What is an AICD or ICD?
automatic implantable cardio-defibrillator
What are the functions of an AICD?
- Antitachycardia Pacing
- Cardioversion
- Defibrillation
- Bradycardia Pacing
What pts are considered for an ICD?
Hx of VF or VT with or without syncope
EF <= 40%
What are pharmaceutical therapies to prevent arrhythmias? (2)
Sotelol
Amiodarone
Note: Usually given in conjuction to placement of ICD.
What is depicted?
Antitachycardia pacing
What is depicted?
Cardioversion from an ICD
What is depicted?
Defibrillation of ICD
In ICDs, which waveform is more prevalent because it requires less energy and results in less myocardial damage when defibrillating?
Biphasic
What is depicted?
Lown biphasic defibrillator waveform
Label
Label:
Before surgical procedures in a pt with ICD, what should you do?
Place in asynchronous mode or place magnet on it.
Bovie is misinterpreted as actual HR.
