Pacemakers and Implantable Cardioverter Defibrillators

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Pacemakers and Implantable Cardioverter
Defibrillators

• Dr. Sivaraman Yegya-Raman

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Temporary and Permanent Cardiac Pacing

• Introduction
• Temporary pacing Indications, Technique
• Permanent Pacing
• Nomenclature
• Indications
• Pacing for Hemodynamic Improvement
• Pacemaker Implantation, Complications
• Implantable Cardioverter Defibrillator

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Temporary Cardiac Pacing

• Transvenous
• Transcutaneous
• Epicardial
• Transesophageal

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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

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Temporary Transvenous Pacing Electrograms
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Permanent Pacing
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The Pacemaker System

• Patient

• Lead

• Pacemaker

• Programmer

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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

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Castle LW, Cook S Pacemaker radiography. In Ellenbogen KA, Kay GN, Wilkoff BL eds Clinical Cardiac Pacing. Philadelphia, WB Saunders, 1995, p 538.

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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

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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

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Codes Describing Pacemaker Modes
Position 1 2 3 4 5
Function Chambers Paced Chambers Sensed Response to Sensing Rate Modulation Multisite pacing
Specific Designations Onone AAtrium VVentricle DDual-Atrium and Ventricle Onone AAtrium VVentricle DDual-Atrium and Ventricle Onone TTriggered IInhibited DDual-Triggered and Inhibited Onone RRate modulation Onone AAtrium VVentricle DDual-Atrium and Ventricle
NASPE/BPEG 2002
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DDD
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Indications for Pacing for AV Block
Degree Pacemaker necessary Pacemaker probably necessary Pacemaker not 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 Asymptomatic type II Asymptomatic type I at intra-His or infra-His levels Asymptomatic type I at supra-His (AV nodal) block
First Asymptomatic or symptomatic
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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 lt40 bpm without a clear-cut association between significant symptoms and the bradycardia Asymptomatic sinus node dysfunction
Symptomatic sinus bradycardia due to long-term drug therapy of a type and dose for which there is no accepted alternative
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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?

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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

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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

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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

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Sources of Electromagnetic Interference

• Medical
• MRI
• Lithotripsy
• Electrocautery/cryosurgery
• External defibrillators
• Therapeutic radiation

• Nonmedical
• Arc welding equipment
• Automobile engines
• Radar Transmitters

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Biventricular Pacing
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Normal Conduction Is Important

• 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

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Cardiomyopathy, LBBB, Heart Failure

• Delayed lateral wall contraction
• Disorganized ventricular contraction
• Decreased pumping efficiency

Sinus node
AV node
Conduction block
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Heart FailureBifocal Ventricular Pacing

• Intraventricular Activation
• Organized ventricular activation sequence
• Coordinated septal and free-wall contraction
• Improved pumping efficiency

Conduction block
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Bi-Ventricular Pacing
Right atrial lead
Coronary sinus lead
Right ventricular lead
N Engl J Med 2003
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SVC coil
RA lead
LV lead
RV coil
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RA lead
LV lead
RV lead
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Bi-V Pace
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Implantable Cardioverter Defibrillator (ICD)
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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.

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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

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Ellenbogen K A, 2007

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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

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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)

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• 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

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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
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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

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Future Directions

• Leadless pacing
• Biological pacemakers
• Subcutaneous ICD