Pacemakers and Implantable Defibrillators

Worldwide, > 250,000 permanent cardiac pacemakers implanted each year.
The primary role of cardiac pacing is to augment or replace the heart's intrinsic electrical system.

Pacemaker
Temporary
Permanent

Epicardial
Endocardial

Single-Chamber System
Dual-Chamber Systems

Temporary pacing
Transcutaneous
Transvenous

Transcutaneous pacing

Transvenous temporary pacing

Temporary pacemaker(2)
Transvenous
-Subclavian
-Jugular
- Femoral

Common Indications for Temporary Pacing
Complete heart block
Sinus bradycardia
Prior to the implant/replacement of a permanent pacemaker
Acute myocardial infarction complicated by heart block
Temporary support of a patient after heart surgery

Epicardial pacing

Permanent Pacemaker

Pacemaker Components
Pulse generator
Leads
programmer

• Complete Heart Block or high grade 2nd degree A-v block
• Sick Sinus Syndrome
Common Indications for Implantable Cardiac Pacemaker

Stimulate cardiac depolarization
Sense intrinsic cardiac function
Respond to increased metabolic demand by providing rate responsive pacing
Provide diagnostic information stored by the pacemaker
Most Pacemakers Perform Four Functions:

Pacing
Sensing

Pacemaker Nomenclature

Atrial and ventricular pacing

Pacemaker interrogation
and programming

Example 1
Ventricular sensed, ventricular paced
Consistent with VVI
The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Example 2
Atrial sensed, ventricular paced
Consistent with DDD or VDD
The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Example 4
Failure to Pace
The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Failure to capture

Complications
Infection or erosion
Hematoma
Pneumothorax
Lead dislodgment
Lead malfunctions or fractures
Electromagnetic interference

Reddy VY et al. N Engl J Med 2015;373:1125-1135.
The Leadless LPacemaker.

Implantable Cardiac Defibrilator

Implantable Cardiac Defibrilator

Inventor of the ICD
Michel Mirowski, M.D.
1924-1990

Indications
1. Cardiac arrest due to VF or VT not due to a transient or reversible cause.
2. Spontaneous sustained VT in association with structural heart disease.
3. Syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiologic study
4. Nonsustained VT in patients with coronary disease, prior myocardial infarction, LV dysfunction, and inducible VF or sustained VT at electrophysiologic study
5. Spontaneous sustained VT in patients without structural heart disease

Antitachycardia pacing

LV dysfunction
EF < 30% - ICD implantation
EF 30-40% -Monitor
NSVT
EPS

Subcutaneous defibrilator

External vest defibrilator

CLBBB

LV dysfunction + wide QRS

Cardiac resyncronization