Pacemakers and ICDs Flashcards

1
Q

Medical devices used to generate and deliver electrical impulses to the myocardium to stimulate a normal heartbeat

A

Artificial pacemakers

Some are external to body and provide temporary treatment, others are permanently implanted in the chest

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2
Q

Temporary pacemakers are ________

A

Transcutaneous

Delivers electrical impulses through lead wires to electrode pads applied to surface of patient’s chest (UNCOMFORTABLE)

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3
Q

Permanent pacemakers are implanted in ….

A

A surgically created pocket beneath the skin in the patient’s chest wall just below the clavicle

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4
Q

Components of permanent pacemakers

A

Generator

Lead wire(s)

Power source (ie lithium battery)

Logic circuits that detect cardiac electrical activity and determine the appropriate response

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5
Q

Conditions in which permanent pacemakers may be used

A

Symptomatic bradycardia

Sick sinus syndrome

Atrial fibrillation w/ bradycardia

3rd degree AV heart block

Symptomatic 2nd degree AV heart block type II

Sudden combo of AV block or BBB if patient has acute MI

Recurrent tachycardias (ICD only)

Synchronization of the heart beat in HF

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6
Q

What is the Indication Paradigm with regards to permanent pacemakers?

A

NON-reversible

SYMPTOMATIC

BRADYCARDIA
• Sinus node dysfunction
•2nd/3rd Degree AVB
•AVN ablation

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7
Q

Symptoms of Bradycardia

A
Syncope or pre-syncope
Dizziness
CHF
Mental confusion
Palpitations
SOB
Exercise intolerance
FATIGUE (relentless)
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8
Q

Where are pacemaker electrodes positioned for single-chamber electrodes?

A

In the atrium or ventricle alone

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9
Q

Where are pacemaker electrodes positioned for duel-chamber pacemakers or AV sequential pacemakers?

A

In both the atrium and ventricle

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10
Q

How are permanent pacemakers programmed?

A

To receive and transmit data/programming instructions through the skin using electromagnetic waves

Adjustments can be made to output, sensitivity, refractory period, and rate adaption

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11
Q

What is the pacing mode for single-chamber pacemakers?

A

One pacing lead is inserted into either the right atrium or right ventricle but not both

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12
Q

What are pacing modes like for dual-chamber pacemakers?

A

Leads are placed into two chambers one lead paces atrium, other lead paces ventricle

By assisting the heart in coordinating the function between the chambers, it acts similarly to how the heart naturally paces itself

Most can be programmed to a single chamber mode (useful if atrial lead wire fails)

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13
Q

Which pacing mode is this:

Paces the heart at a single, preset rate

A

Fixed-rate

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14
Q

Which pacing mode is this:

Sensors identify increases or decreases in the patient’s physical activity and automatically adjusts base pacing rate to meet the body’s metabolic needs

A

Rate-responsive

Can boost HR in response to motion or increased respiration’s - good for those whose body cannot increase the HR during activity

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15
Q

Which pacing mode is this:

Most common type

A

Demand

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16
Q

Which pacing mode is this:

Fires only when the patient’s intrinsic HR falls below a given threshold level (ie 60 bpm)

A

Demand

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17
Q

Which pacing mode is this:

Parameters in which device will activate

A

Lower/Upper Rate Limits

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18
Q

Pacemaker mode and function are described by…

A

A 5-letter coding system (though in practice, only 3-4 are commonly used)

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19
Q

Pacemaker coding system:

1st letter: _______

2nd letter: _______

3rd letter: _______

4th letter: _______

5th letter: _______

A

The chamber being PACED

The chamber being SENSED

How the pacemaker generator RESPONDS to sensing

Whether the RATE-RESPONSE FEATURE is activated

Indicates multisite pacing (rarely used)

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20
Q

For the first letter of the pacemaker coding system, what letters are used and what do they mean?

A

Chamber being paced

O = none
A = atrium
V = ventricle
D = dual (both atrium and ventricle)
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21
Q

For the second letter of the pacemaker coding system, what letters are used and what do they mean?

A

Chamber being sensed

O = none
A = atrium
V = ventricle
D = dual
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22
Q

For the third letter of the pacemaker coding system, what letters are used and what do they mean?

A

How the pacemaker generator responds to sensing

O = none
T = triggers pacing
I = inhibits pacing
D = dual (triggers and inhibits)
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23
Q

For the fourth letter of the pacemaker coding system, what letters are used and what do they mean?

A

Whether the rate-response feature is activated

O = none
R = rate responsive
24
Q

For the fifth letter of the pacemaker coding system, what letters are used and what do they mean?

A

Indicates multisite pacing

O = none
A = atrium
V = ventricle
D = dual
25
Q

What does this code mean:

VOO

A

Asynchronous ventricular pacing
• Ventricular pacing
• Ø sensing
• Ø response to sensing

Do to surgery where bovine used causes interference or applied magnet

DO NOT LEAVE PATIENT LIKE THIS

26
Q

What does this code mean:

VVIR

A

Ventricular inhibitory pacing with rate modulation
• Ventricular pacing
• Ventricular sensing
• Inhibits ventricular pacing if activity sensed
• Rate-response active

Used for chronic afib patients, or those needing resynchronization (BIV)

27
Q

What does this code mean:

AAI

A

Atrial inhibitory pacing, no rate modulation
• Atrial pacing
• Atrial sensing
• Inhibits atrial pacing if atrial activity sensed

Used for SA node dysfunction, normal AV conduction (not a common mode)

28
Q

What does this code mean:

DDDR

A
Dual-chamber pacing
• Dual pacing
• Dual sensing
• Dual response (inhibitors and triggers)
• Rate modulating

AV sensed/AV pace/inhibited and triggered

29
Q

What does this code mean:

DDI

A

Dual chamber pacing without atrial-synchronous ventricular-pacing
• Dual-paced
• Dual-sensed
• Inhibits ventricular pacing if ventricular activity sensed

Indicates pacemaker unable to “track” atrial rate to direct ventricular pacing (mode switch)

Avoids ventricular tracking of abnormally high atrial rates

30
Q

What does this code mean:

ODO

A

Pacemaker is OFF

31
Q

Most pacemakers perform these four functions…

A

Stimulate cardiac depolarization

Sense intrinsic cardiac function

Respond to increased metabolic demand by providing rate responsive pacing

Provide diagnostic info stored by the device (may dx atrial or ventricular arrhythmias)

32
Q

What is Cardiac Resynchronization Therapy (CRT)?

A

Resynchronize biventricular contraction, a common problem in patients with heart failure

Employs three leads (one in atrium, one in right ventricle, one inserted through coronary sinus to pace the free wall of the left ventricle)

33
Q

Where are the three leads located in CRT?

A

Right atrium

Right ventricle

Through the coronary sinus to the free wall of the left ventricle

34
Q

Name the system:

Positive electrode is positioned in the heart tissue and the negative electrode is connected to the pulse generator

A

Unipolar system

35
Q

Unipolar systems produce __________ spikes on the ECG

A

Tall pacing spikes

36
Q

Name the system:

Electrodes are only millimeters apart in the cardiac tissue

A

Bipolar system

37
Q

Bipolar systems produce _______ spikes on ECG

A

Short pacemaker spikes

38
Q

ECG features of a pacemaker depend on…

A

How many chambers are paced

The firing of a pacemaker produces one or two narrow pacemaker spikes

39
Q

What are the two features of a paced ECG complex?

A

Narrow “pacing spikes” which reflect the impulse depolarizing the paced chamber

P wave or QRS complex that immediately follows the pacing spike

40
Q

Reasons why your granddaddy’s pacemaker might not work right…

A

Failure to capture
Failure to sense
Failure to pace (oversensing)
Pacemaker-mediated tachycardia

41
Q

Presence of pacemaker spikes that are not followed by a P wave or broad QRS complex

A

Failure to capture

42
Q

How do you recognize failure to capture?

A

Presence of pacemaker spikes that are not followed by a P wave or broad QRS complex

43
Q

Presence of ECG pacemaker spikes that fall where they should have been inhibited

A

Failure to sense

44
Q

How do you recognize failure to sense?

A

Presence of ECG pacemaker spikes that fall where they should have been inhibited

45
Q

Absence of pacemaker spikes in the presence of a heart rate that is slower than the rate set for the pacemaker

A

Failure to pace (oversensing)

46
Q

How do you recognize failure to pace on ECG?

A

Absence of pacemaker spikes in the presence of a HR that is slower than the rate set for the pacemaker

47
Q

Fast HR with a pacemaker spike preceding each QRS complex on ECG

A

Pacemaker-mediated tachycardia

48
Q

How do you recognize pacemaker-mediated tachycardia?

A

Fast HR with a pacemaker spike preceding each QRS complex on ECG

49
Q

Implanted Cardioverter-Defibrillators (ICD) are implanted in patients who…

A

Are at risk of sudden cardiac death due to ventricular fibrillation and ventricular tachycardia

50
Q

Implantable Cardioverter-Defibrillators are programmed to detect ________ and correct them by _______

A

Cardiac dysrhythmias

Delivering paced beats, cardioversion, or defibrillation

51
Q

What are the different types of therapies provided by ICD

A

Antibradycardia pacing

Antitachydysrhythmia pacing

Cardioversion

Defibrillation

52
Q

Which ICD therapy:

Electrical pacing is used to increase the HR when it is too slow.

A

Antibradycardia pacing

Most ICDs can pace one chamber at a preset rate. Some can sense and pace both chambers.

53
Q

Which ICD therapy:

Mode that generates a series of small, rapid electrical pacing pulses to interrupt ventricular tachycardia (by “capturing” the ventricle and breaking the reentry circuit) and return the heart to its normal rhythm

A

Antitachydysrhythmia pacing

54
Q

Which ICD therapy:

Mode that uses a low- or high-energy shock (up to 35 joules), which is timed to the R wave (which is detected by the right ventricular electrode) to terminate VT and return the heart to its normal rhythm

A

Cardioversion

55
Q

Which ICD therapy:

Mode that delivers a high-energy shock (up to 35 joules) to the heart to terminate ventricular fibrillation and return the heart to its normal rhythm

A

Defibrillation

56
Q

Electromagnetic fields that may affect pacemakers are ______

A

Radio-frequency waves

50-60 Hz are most frequently associated with pacemaker interference

Few sources of EMI are found in the home or office but several exist in hospitals

57
Q

Sources of EMI that interfere with pacemaker operation include…

A

Electrocautery (if within 6 in of heart)

Transthoracic defibrillation (if req’d do not withhold)

Extracorporeal shock-wave lithotripsy (if abd device)

Therapeutic radiation (requires device shielding)

RF ablation (defer to EP doing case)

TENS units (fine if bipolar system, avoid if unipolar)

MRI (may compatible systems now)