Pacemakers and Implantable
Cardioverter Defibrillators
Dr. Sivaraman Yegya-Raman
Temporary and Permanent Cardiac Pacing
• Introduction
• Temporary pacing : Indications, Technique
• Permanent Pacing :
Nomenclature
Indications
Pacing for Hemodynamic Improvement
Pacemaker Implantation, Complications
•
Implantable Cardioverter Defibrillator
Temporary Cardiac Pacing
• Transvenous
• Transcutaneous
• Epicardial
• Transesophageal
Indications for Temporary Pacing
 Acute myocardial infarction with:
CHB, Mobitz type 2 AV block, medically
refractory symptomatic bradycardia,
alternating BBB, new bifascicular block, new
BBB with anterior MI
 In absence of acute MI : SSS, CHB, Mobitz
type 2 AV block
 Treatment of tachyarrhythmias : VT
Temporary Transvenous Pacing
Electrograms
Permanent Pacing
The Pacemaker System
• Patient
 Lead
 Pacemaker
• Programmer
Lead
Pacemaker
Pacemaker Implantation
• Transvenous :
• Generator implanted anterior to pectoral muscle
• Atrial/Ventricular leads via subclavian or cephalic
vein
• Sensing and pacing threshold
• Chest X-ray for pneumothorax, lead position
Castle LW, Cook S: Pacemaker radiography. In Ellenbogen KA, Kay GN, Wilkoff BL [eds]: Clinical Cardiac Pacing. Philadelphia, WB Saunders, 1995, p 538.
Acute Complications of Pacemaker
Implantation
• Venous access
Pneumothorax, hemothorax
Air embolism
Perforation of central vein
Inadvertent arterial entry
• Lead placement
Brady – tachyarrhythmia
Perforation of heart, vein
Damage to heart valve
• Generator
Pocket hematoma
Improper or inadequate connection of lead
Delayed Complications of Pacemaker Therapy
• Lead-related
Thrombosis/embolization
SVC obstruction
Lead dislodgement
Infection
Lead failure
Perforation, pericarditis
• Generator-related
Pain
Erosion, infection
Migration
Damage from radiation, electric shock
• Patient-related
Twiddler syndrome
Codes Describing Pacemaker Modes
Position
1
Function
Chambers
Paced
Chambers
Sensed
Response
to Sensing
Rate
Multisite
Modulation pacing
Specific
Designations
O=none
A=Atrium
V=Ventricle
D=DualAtrium and
Ventricle
O=none
A=Atrium
V=Ventricle
D=DualAtrium and
Ventricle
O=none
T=Triggered
I=Inhibited
D=DualTriggered and
Inhibited
O=none
R=Rate
modulation
2
3
4
5
O=none
A=Atrium
V=Ventricle
D=DualAtrium and
Ventricle
NASPE/BPEG 2002
DDD
Indications for Pacing for AV Block
Degree
Pacemaker necessary
Third
Symptomatic congenital
complete heart block
Aquired symptomatic complete
heart block
Atrial fibrillation with complete
heart block
Acquired asymptomatic
complete heart block
Second
Symptomatic type I
Symptomatic type II
First
Pacemaker
probably
necessary
Pacemaker not
necessary
Asymptomatic
Asymptomatic type
type II
I at supra-His (AV
nodal) block
Asymptomatic
type I at intra-His
or infra-His levels
Asymptomatic or
symptomatic
Indications for Pacing for Sinus Node Dysfunction
Pacemaker
Pacemaker probably
necessary
Pacemaker not
necessary
Symptomatic bradycardia
Symptomatic patients
with sinus node
dysfunction with
documented rates of <40
bpm without a clear-cut
association between
significant symptoms and
the bradycardia
Asymptomatic sinus node
dysfunction
Symptomatic sinus
bradycardia due to longterm drug therapy of a
type and dose for which
there is no accepted
alternative
Case #1
72 year old male with chronic atrial
fibrillation of greater than 10 years’ duration is
admitted following a syncopal episode. A 2D
echo shows LVEF 60%. Telemetry reveals atrial
fibrillation with slow ventricular response and
pauses of 5 to 6 seconds associated with
lightheadedness.
How would you proceed?
Case #1
72 year old male with chronic atrial fibrillation of
greater than 10 years’ duration is admitted
following a syncopal episode. A 2D echo shows
markedly dilated left atrium and LVEF 60%.
Telemetry reveals atrial fibrillation with slow
ventricular response and pauses of 5 to 6 seconds
associated with near syncope.
How would you proceed?
Answer: Implant a ventricular rate responsive
pacemaker
Pacemaker Follow-up
• GOAL OF FOLLOW-UP
– Verify appropriate pacemaker operation
– Optimize pacemaker functions
– Document findings, changes and final settings in
order to provide appropriate patient management
“Pacemaker Syndrome”
• Fatigue, dizziness, hypotension
• Caused by pacing the ventricle asynchronously,
resulting in AV dissociation or VA conduction
• Mechanism: atrial contraction against a closed AV
valve and release of atrial natriuretic peptide
• Worsened by increasing the ventricular pacing rate,
relieved by lowering the pacing rate or upgrading to
dual chamber system
• Therapy with fludrocortisone/volume expansion NOT
helpful
Sources of Electromagnetic Interference
• Medical
– MRI
– Lithotripsy
– Electrocautery/cryosurger
y
– External defibrillators
– Therapeutic radiation
• Nonmedical
– Arc welding
equipment
– Automobile engines
– Radar Transmitters
Biventricular Pacing
Normal Conduction Is Important
Sinus
node
AV
node
• Normal conduction
allows for prompt
and synchronous
activation of the
atria and ventricles
• Results in a brief P
wave, PR interval
and a narrow QRS
Cardiomyopathy, LBBB, Heart Failure
Sinus node
AV
node
Conduction
block
• Delayed lateral wall
contraction
• Disorganized ventricular
contraction
• Decreased pumping
efficiency
Heart Failure
Bifocal Ventricular Pacing
• Intraventricular Activation
• Organized ventricular
activation sequence
• Coordinated septal and
free-wall contraction
• Improved pumping
efficiency
Sinus node
AV
node
Conduction
block
Stimulation
therapy
Bi-Ventricular Pacing
Right atrial lead
Coronary sinus lead
Right ventricular lead
N Engl J Med 2003
SVC coil
RA lead
LV lead
RV coil
RA lead
LV lead
RV lead
Bi-V Pace
Implantable Cardioverter Defibrillator
(ICD)
ICD Implantation
• Secondary prevention: Prevention of SCD in
patients with prior VF or sustained VT.
• Primary prevention: Prevention of SCD in
individuals without a h/o VF or sustained VT.
Indications For ICD
• VF/sustained unstable VT not in the setting of a
completely reversible cause.
• LVEF ≤ 35%, CHF NYHA class II, III.
• Ischemic dilated cardiomyopathy, LVEF ≤ 40%, NSVT
and inducible sustained VT.
• Syncope, LV dysfunction, inducible sustained VT.
• High risk patients with: hypertrophic
cardiomyopathy, LQT syndrome, RV dysplasia,
Brugada syndrome
Ellenbogen K A, 2007
ACC/AHA/HRS 2008 Guidelines: Systolic Heart Failure Cardiac Resynchronization Therapy (CRT)
Recommendations
• LVEF ≤ 35%
• QRS ≥ 120 msec
• NYHA functional Class III or
ambulatory Class IV
• Optimal medical therapy
“Typical Case”
58 year old male, CAD, prior MI, EF 28%, CHF, NYHA
class II, Medications: Furosemide 40 mg, Enalapril 20
BID, Aldactone 25 qd, Carvedilol 25 BID, no syncope
or VT, ECG: Sinus rhythm, old anteroseptal MI, QRS
92 msec
Based on available trial data, you would suggest:
A. Treating medically without device implantation
B. Implanting an ICD
C. Implanting an ICD with biventricular pacing
capabilities (3 leads)
Typical Case
Q: 60 year old female presents with a 1
year h/o non ischemic dilated
cardiomyopathy, CHF NYHA class III
despite maximum medical therapy, LVEF
20% and LBBB with QRS 170 msec. What
device is indicated?
A: Bi-Ventricular ICD
1° Prevention: Clinical Device Algorithm
If Non –Ischemic Dilated Cardiomyopathy:
& EF ≤ 35%
ACE inhibitors, Beta Blockers
ICD
If LVEF ≤ 35%, CHF Class III-IV, QRS ≥ 120 ms
BiV ICD
Magnet Application on Pacemaker/ICD
• Pacemaker:
– Disables sensing
– Changes to VOO or DOO mode
– Useful if cautery is being used in PPM dependent pt.
• ICD:
– Disables Tachycardia sensing
– Useful at bedside if pt. has ventricular lead fracture or Afib
with rapid ventricular response causing ICD shocks
– Prevents ICD shock during cautery application at surgery
Future Directions
• Leadless pacing
• Biological pacemakers
• Subcutaneous ICD