Pacers Flashcards
Indications for insertion of pacemakers:
-Sinus node disease
-AV node disease
-Long QT syndrome
-Hypertrophic obstructive cardiomyopathy
-Dilated cardiomyopathy
“SALHD”
PaSeR PM
- Pased
- Sensed
- Response to Sensing
- programability
- multisite pacing
O-
A-
V-
D-
O- none
A- atrium
V- ventricle
D- dual
Failure to capture:
when the pacemaker’s electrical output fails to cause myocardial depolarization
Failure to sense:
the pacemaker fails to recognize intrinsic cardiac electrical activity
Indications for ICD:
o Ventricular tachycardia
o Ventricular fibrillation
o Post MI with an EF <30%
o Cardiomyopathy with an EF <35%
o Hypertrophic cardiomyopathy
o Awaiting a heart transplant
o Long QT syndrome
ICD: Position 1
Shock Chambers
ICD: Position 2
Anti-Tachycardia pacing chambers
ICD: Position 3
Tachycardia Detection
ICD: Position 4
Anti-Bradycardia pacing chambers
An ICD cardioverts V-tach with________ joules.
1-30
An ICD cardioverts V-Fib with________ joules.
10-30
-if an ICD acknowledges that a shock is needed, it will deliver six shocks
Electrocautery =
most prevalent source of electromagnetic interference in the operating room
Bipolar cautery
has the anode and cathode at the tip of the device less of a risk of EMI versus a monopolar cautery device which requires a grounding pad to be placed elsewhere on the body
Application of a magnet on a pacemaker will…..
will set the pacemaker into the set asynchronous pacing rate –> may disable any rate modulation that could set with the pacemaker
Application of a magnet on an ICD:
will disable the ability of ICD to shock VT or VF
Application of a magnet on a dual pacemaker AND ICD:
Will ONLY disable the shock function
Explain Asynchronous Pacing
-Pacer gives a constant rate
-No sense or inhibition
-There CAN be a competitive underlying rhythm
-A pacer spike delivered during ventricular depolarization can result in “R on T”
Example: AOO, VOO, DOO
Single-Chamber Demand Pacing
-Think of this as a backup mode. It only fires when the native heart rate falls below a predetermined rate.
Example: AAI, VVI
Dual-Chamber AV Sequential Demand Pacing
-This mode is very flexible and is the MOST COMMON mode of pacing.
-This mode makes sure the atrium contract first followed by the ventricle
-This improves AV synchrony
Example: DDD
What is the best option for a surgeon to use for cautery?
Bipolar Device
What I the most critical information to have preoperatively?
The patients underlying rhythm
Pacemaker failure can be treated with ________, ________, and _________. (depends on underlying rhythm).
Isoproterenol, epinephrine, atropine
Failure to sense occurs when the pacemaker does not sense __________.
The underlying cardiac rhythm
Undersensing results in _____________ pacing
Asynchronous pacing
Failure to capture occurs when the _______ does not ________ in response to a pacing stimulus.
ventricle, depolarize
During failure to sense, the pacemaker ends an impulse at _______ times. You’ll see ________ _______ in places where you would otherwise not expect to see them.
sporadic, pacing spikes
Failure to output can be caused by _______, ________, ________.
overspending, pulse generator failure, or lead failure.
Contraindication for patients with pacer or ICD
MRI
NOT Contraindications:
Lithotripsy (beam directed away from the pulse generator) and Electroconvulsive therapy
SATA (ICD 1,2,3,4)
- Shock Chambers
- Anti-Tachycardia pacing chambers
- Tachycardia sensing
- Anti-Bradycardia pacing chambers
Position 1: pacer
chamber paced
Position 2: pacer
chamber sensed
Position 3: pacer
O =
I =
T =
D =
Response to sensing
Ex. sensed intrinsic atrial beat will inhibit atrial pacing output and will trigger ventricular pacing
O = none
I = inhibited
T = triggered
D = dual (T+I)
Position 4: pacer
R = ?
O= ?
Programmability
O= none
R = rate modultion (will increase the pacer’s lower heart rate limit in response to activity that may require an increased myocardial oxygen demand)
Position 5: pacer
Multisite pacing (pacer may pace BOTH atria and/or BOTH ventricles
