Pacemaker questions Flashcards Preview

From Flashcardlet big > Pacemaker questions > Flashcards

Flashcards in Pacemaker questions Deck (32):

What are typical temporary epicardial pacemaker settings follow cardiac surgery

Rate 90 bpm
Atrial output 5mA
atrial sensitivity 1.0 mV
Ventricular 5mA
Ventricular sensitivity 2.0mV
Atrioventricular delay (AVD) 150 msec
Mode (DDD)


Compared to NSR VVI pacing causes decreased cardiac output. Describe 2 mechanisms that account for this decrease

Loss of atroventricular synchrony (atrial kick)

loss of depolarization via purkinje system resulting discordant ventricular contraction


List 3 diagnoses or groups of patients that are particulary adversely affected by the loss of sinus rhythm

Those with ventricular hypertrophy (aortic stenosis, severe HTN)
Those in congestive heart failure
mitral stenosis


List 5 items which may be tracked and used to modulate the rate in a rate responsive pacemaker

carbon dioxide
lactic acid
intra-cardiac pressure


How do rate responsive pacemakers work

Particular item is a product of increased metabolism and will be sensed by a transducer. This results in an electrical signal being sensed by the pacemaker electronic circuit and changes the pacemaker automatic interval and therefore the escape rate. As detectino of the item increases, the pacemaker output rate will icnrease, as the sensed paramter decrease, the pacemaker response will also decrease


Describe 2 ways which you would achieve permanent ventricular pacing in a patient with complete heart block and a previously placed mechanical valve in the tricuspid position

Epicardial pacing (subxyphoid, or anterior thoractomy approach)

Transvenous, transcoronary sinus, coronary vein LV wall pacing


Why not cross the Tricuspid valve

Potential damage to the valve
increasing tricuspid regurgitation
increasing possibility of jamming leaflet of a mechanical prosthesis


implanting an automatic internal defibrillator. What are anatomic boundaries that guide a cephalic vein cut down

pectoralis major
"Delto-pectoral groove"


List 2 advantages of cephalic vein cut down over direct subclavian percutaneous cannullation

less chance of lead trauma (crush injury)

less chance of hemothorax

less chance of pneuo

Less chance of chylothorax


Briefly describe the function of a pacemaker designated by the following 3 letters of the International pacemaker code
1) AOO
2) AAI
3) DVI
4) DDD
5) VOO

AOO: fixed-rate atrial pacer
AAI: (rate inhibited), atrial pacer
DVI: Double chamber pacing but only ventricular sensing
DDD: chamber pacing and double change sensing
VOO: Fixed rate, ventricular pacer


List 3 sensor that can be incorporated into a rate-adpative pacemaker

activity (movement)
minute ventilation
QT interval


What is pacemaker tachycardiac

Initiated when ventricular activity is conducted retrograde to the atria results in a premature atrial depolarization.
Pacemaker sense the retrograde-induced atrial event and paces the ventricle following the programmed AV delay. If the verntricular events is again conducted retrograde to the atraium, the endless loop cycle develops.


Why does PMT occur

Loss of AV synchorny

Can be be causes by over/under sensing or loos of atrial capture./PAV/magnet removal

retrograde conduction is related to status of AV node condution. If sinus node dysfunction and intact AV node then retrograde conduction is possible


What is treatment of PMT

Measure the VA conduction time and program a post ventricular atrial rerfractory period (PVRP) that is equal to the VA condution time plus 50ms

PVRP: is the period after a sensed or paced ventricular event which the atrial sensing circuit is refractory. Any atrial event occuring during the PVRAP will not be sense by the atrial circuit.


What features of the pacemaker must occur in order to have PMT

Dual chamber
atrial sensed
loss of AV snychrony.. (sinus node dysfunction with normal AV node condution)


What is Magnet Mode

Causing sensing to be inhibited

temporary turns pacemaker into asynchronus mode "set rate' "VOO"


What is DDD

paces atria and ventricle
senses atrial and ventricle
atria triggered and ventricle inhibited



Paces atria
senses atria
triggers generator to fire if atria sensed


What are actions of ICD

Perform cardioversion/defibrillation
Anti-tachycardia pacing--overdrive pacing in an attempt to terminate ventricular tachycardia.


List absolute indications for PPM

1. Sick Sinus syndrome
2. Symptomatic sinus bradycardia
3. trachy-brady syndrome
4. 3rd degree heart block
5. AF with slow ventricular response
6. Chronotropic incompetence
7. Prolonged QT syndrome


What does magnet do for pts with ICD

Disables the tachyarrhythmia and therefore does not allows shocks

Magnet does NOT cause asynchronus pacing it would in a pacemaker


Class I indications for AICD

Following sudden cardiac death due to VF or HD instability with VT after excluding reversible causes
Structural heart disease and spontateous sustained VT
Syncope of unclear origin and inducible VF or VT on EPS
LVEF <35% due to MI, 40 days post MI, NYHA II-III
LVEF 30%, prior MI, NYHA class I
NSVT due to prior MI, LVEF <40%, , VF or VT on EPS


What are class IIa indications for AICD

Unexplained syncope, significant LV dysfunction, non-ischemic DCM
Sustained VT, normal EF
HCM with 1 or more RF for SCD
ARVD/C with 1 or more RF for SCD
Long QT with syncope and VT while on BB
Non-hospitalized pts awaiting transplant
Brugada syndrome with syncope


Most common reasons to remove AICD

Lead fracture


Most common reasons for inappropriate defibrillation/shock

fractured lead


Where do you see the leads for ICD

leads go into the right atrium and the right ventricle

for for CRT you would see a third lead in that goes retrograde through the CS in the LV


What percentage of pts receiving a CRT do not receive any benefit

about 30%

some actually get worse


List 3 sensors that can be incorporated into a rate-adaptive pacemaker

Activity (movement
Minute ventilation
QT interval


What type of pacemaker and why

79 yo pt with longstanding AF, R from 30 to 100bpm on medical treatment, good ventricular function


VDD and DDD are contraindicated due to lack of organized atrial activity and risk of tracking atrial tachyarrhythmias

*pt has lived without atrial quick so will not benefit and if you place dual you run the risk of PMT


What type of pacer and why
8 year old 23 KG with complete heart block


AV synchrony and rate responsiveness is maintained, single lead minimizes risk of subclavian vein thrombosis

DDD is acceptable but the 2 leads is less ideal in smaller children when the same effect can be had with single lead VDD system


What type of pacer and why

80 year old F, with bradycardia persisting for 1 week following AVR. Pre-op EF at 35%. Rhytm strip shows sinus bradycardia with heart rates of 35bpm with PR interval and occasional 2:1 block


best due to reduced preoperative EF in a hypertrophied ventricle that would be very preload sensitive

VDD not ideal due to need for occasional atrial pacing


What is the North Americans Society of Pacing and Electrophysiology five-position pacemaker classification system

I: Chamber paced--
O--(none); A (atrium), V (Ventriclle, D (dual A + V); S (single A or V)
II: Chamber sensed
O--None; A (atrium), V (ventricle); D (dual A + v); S (single A or V)
III: response to sensing
O---None; T (triggered) ; I (inhibitied); D (dual)
IV: Programmability
O--None, R (Rate modulation)
V: Multisite pacing
O (none), A (atrium), V (ventricle),D (dual A + V)

Decks in From Flashcardlet big Class (79):