L8: Pacemakers

Question 1

To get a pacemaker, the patient MUST have

Answer 1

NON-Reversible
SYMPTOMATIC
BRADYCARDIA

Question 2

Kinds of bradycardia that might need to be paced

Answer 2

Sinus Node Dysfunction
2nd- / 3rd-Degree AVB
AVN ablation (iatrogenic complete AVB)

Question 3

Symptoms of bradycardia

Answer 3

• Syncope or pre-syncope
• Dizziness
• Congestive heart failure
• Mental confusion
• Palpitations
• Shortness of breath
• Exercise intolerance
• FATIGUE (relentless)

Question 4

Dual-chamber pacemakers aka

Answer 4

AV sequential pacemakers

Question 5

4 functions of a pacemaker

Answer 5

1. Stimulate cardiac depolarization
2. Sense intrinsic cardiac function
3. Respond to increased metabolic demand by providing rate responsive pacing
4. Provide diagnostic information stored by the pacemaker→ May diagnose atrial or ventricular arrhythmias!

Question 6

Cardiac Resynchronization Therapy employs 3 leads:

Answer 6

In right atrium
In right ventricle
Inserted through the coronary sinus to pace
the free wall of the left ventricle

Question 7

Features of a paced ECG complex

Answer 7

Narrow “pacing spike,” which reflects the impulse depolarizing the paced chamber
P wave or QRS complex that immediately follows the pacing spike

Question 8

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

Answer 8

Failure to capture

Question 9

Presence of ECG pacemaker spikes that fall

where they should have been inhibited

Answer 9

Failure to sense

Question 10

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

Answer 10

Failure to pace

Question 11

Fast heart rate with a pacemaker spike preceding each QRS complex on EGG

Answer 11

Pacemaker mediated tachycardia

Question 12

Failure to pace aka

Answer 12

oversensing

Question 13

Who gets an Implantable Cardioverter

Defibrillator

Answer 13

patients who are at risk of sudden cardiac death due to ventricular fibrillation and ventricular tachycardia

Question 14

Therapies provided by an Implantable Cardioverter

Defibrillator

Answer 14

Antibradycardia pacing→ increases heart rate
Antitachydysrhythmia pacing→ produces small rapid pulses to interrupt vtach by capturing ventricle and disrupting reentry circuit
Cardioversion→ low or high energy shock times to R wave to terminate vtach
Defibrillation→ high energy shock to terminate vtach

Question 15

During Vtach an Implantable Cardioverter

Defibrillator will

Answer 15

Defibrillate

ATP=Antitachycardia pacing

Question 16

During Vfib an Implantable Cardioverter

Defibrillator will

Answer 16

Defibrillate

Question 17

During asystole and an Implantable Cardioverter

Defibrillator will

Answer 17

Pace only

Question 18

Electromagnetic fields that may affect pacemakers are…

Answer 18

Radio-frequency waves

50-60 Hz

Question 19

Sources of EMI that interfere with pacemaker
operation include surgical/therapeutic equipment
such as:

Answer 19

Electrocautery (if within 6 inches 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 (many compatible systems now!)