Pacemakers Ap2

Front 1

What are the components of a Pacemaker?

Back 1

The generator, leads, and electrodes

Front 2

What is the generator?

Back 2

The device containing electrical circuits and energy supply

Front 3

What is the lead?

Back 3

An insulated wire that extends from the generator to the electrode

Front 4

What is the electrode?

Back 4

The portion of the pacemaker that attaches directly to the heart to transmit the generated impulse

Front 5

What are the different types of leads?

Back 5

Unipolar-contains the negative electrode in the heart and the positive electrode in the generator
Bipolar- both electrodes are located 1-2 cm apart in the heart

Front 6

Escape Interval-

Back 6

The time it takes for the generator to emit an impulse in the absence of an R wave

Front 7

Automatic Interval

Back 7

Time in milliseconds b/t successive pacemaker impulses

Front 8

Calculate the rate if the AI is 846?

Back 8

Always divide 60,000 by the AI. So 60,000/846= 71BPM

Front 9

Calculate the AI if the rate is 71BPM?

Back 9

60,000/71= AI of 846

Front 10

Hysteresis-

Back 10

The difference b/t the escape and automatic interval that allows the patients HR to fall below the AI before pacing at the AI is initiated. Allows for small decompensations that may be normal
IE: HR set at 70 the heart rate may be allowed to fall to a normal level of 62 before pacing which may normally occur in rest states.

Front 11

R wave sensitivity

Back 11

Number of millivolts required to activate the sensing circuit. And in turn inhibit the pacing circuit.
If the R wave is rate strong enough (high enough) then the pacemaker will sense it and not initiate.

Front 12

Slew Rate

Back 12

Rate of voltage change of the R wave can change so that T waves and shivering are not noticed as
R waves.

Front 13

Triggered Pacemaker

Back 13

Detects an R wave and initiate impulses exactly at the peak of every R wave on the ECG

Front 14

Inhibited Pacemaker

Back 14

Detects R waves and compares them to the standard program and inactivates impulse if sufficient

Front 15

Rate Adaptive/Rate Response Pacemaker

Back 15

The metabolic state or movement varies the AI to compensate for activity/rest states

Front 16

Blanking period?

Back 16

Occurs immediately after a paced or sensed event so that the pacemaker will not respond to any
ECG events, which prevents any sensing of the T waves

Front 17

The naming of modes of the pacemaker includes what functions?

Back 17

Pacing location
Sensing location
Mode of Activity
Programability
Antitachycardia functions

Front 18

The type of pacemaker that can trigger VT?

Back 18

Asynchronous because it is unrelated to the pts intrinsic rhythm and cannot detect ventricular depolarization.

Front 19

Which pacemaker maintains normal AV conduction?

Back 19

Atrioventricular pacing

Front 20

Which pacemaker prevents chronotropic incompetence?

Back 20

Rate adaptive pacing

Front 21

What technology is employed in rate adaptive pacing?

Back 21

Piezoelectric crystals-senses vibration
Impedence- RR/MV
Thermistor-RV temperature
Pressure-from the RV
Optical Reflectance-senses SaO2 changes

Front 22

Temporary Pacing can occur in what ways?

Back 22

Epicardial-wires placed on heart to external generator during sx
Transcutaneous-pads on chest to stimulate muscle contraction
Transesophageal-flexible electrode to pace atria only
Transvenous-pacing wire or PA pacing cath via vasculature to heart

Front 23

Transvenous pacing access usually occurs where?

Back 23

Subclavian
IJ
**May occur thru femorals as well

Front 24

ICD’s may be placed primarily for which patients?

Back 24

Asymptomatic CAD with ventricular rhythm disturbances
Post CABG with EF < 35% LV dysfunction
Waiting for transplant

Front 25

ICD secondary placement occurs for what reasons?

Back 25

CAD and hx or sudden death
Documented or inducible ventricular arrhythmias

Front 26

Survival rate for sudden death is?

Back 26

One-year survival 70% then declines to 55% survival by end of year two

Front 27

Differences b/t older and newer ICD’s?

Back 27

Now smaller and planted in the chest wall. Can be programmable, longevity of device (9yrs)
Multichamber functions, shorter sx procedures with fewer complications

Front 28

The multidetection zones allow for what functions to occur?

Back 28

Antitachycardia pacing
Cardioversion shocks
Defibrillation

Front 29

How many beats are usually sensed before firing?

Back 29

8-10 fast beats

Front 30

What is the delay before charging begins in an ICD?

Back 30

2.5-10 secs

Front 31

How long for the charge to reach impulse before firing?

Back 31

Another 6-15 seconds

Front 32

What is the charge delivered?

Back 32

0.1-31 joules

Front 33

What is the maximum amt of shocks delivered per cycle?

Back 33

5

Front 34

How does the rate sense in an ICD to determine its need to shock?

Back 34

RR intervals (tachycardia)
Morphology

Front 35

Issues for placement of these devices during anesthesia?

Back 35

Usually have little cardiac reserve with comorbidites (CAD/LVD/VHD/Cardiomyopathy)

Front 36

What should be attached to the patient for these procedures?

Back 36

External defibrillator pads

Front 37

What must one anticipate during placement of these devices?

Back 37

Purposfully inducing VT/VF and attempting successful defibrillation
May need to intubate and secure airway
ACLS may be initiated for sustained arrest-emergency drugs available

Front 38

The main concern for cardiac devices present for routine sx?

Back 38

Electromagnetic interference may occur w/o direct contact that may cause permanent damage to device or cause false firing

Front 39

What part of sx is most likely to interfere with a pacemaker or ICD?

Back 39

The electrocautery-bipolar should be used. If not then current path should be as far away from device as possible.

Front 40

Pacemakers should be reset to what function?

Back 40

Asynchronous mode-done by magnet

Front 41

ICDs should have what done to them prior to sx start?

Back 41

Deactivativation, which is brand dependent
Place external pads on if not interfering with sx field> 6 inches away
Usually just use external paddles

Front 42

What should be done immediately post sx procedure?

Back 42

Turn back on and consult EP to confirm proper functioning

Front 43

Lithotripsy concerns?

Back 43

May be contraindicated with specific brands
May deliver false shock
Usually concerns for abdominally placed ICDs

Front 44

Which procedures will not interfere with ICD/Pacemaker function?

Back 44

Xray1 CT scans
Fluro Ultrasound
Mamograms Laser sx

Front 45

Contraindications for ICD/Pacemakers?

Back 45

MRI
DC ablation

Front 46

Ablation

Back 46

Catheter used to ablate diseased pathways that conduct arrythmias (SVT arrythmias)

Front 47

What type of ablation may offer better but not complete safeness?

Back 47

Radiofrequency ablation over DC ablation

Front 48

Side effects of ablation?

Back 48

Pain during burning
Arrhythmias
Bleeding
PTX
MI/CVA