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

• PatientLead

Pacemaker

• Programmer

LeadLead PacemakerPacemaker

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.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

PositionPosition 11 22 33 44 55FunctionFunction ChambeChambe

rs Pacedrs PacedChamberChambers Senseds Sensed

ResponsResponse to e to SensingSensing

Rate Rate ModulatiModulationon

MultisitMultisite e pacingpacing

Specific Specific DesignatiDesignati

onsons

OO=none=none

AA=Atrium=Atrium

VV=Ventric=Ventriclele

DD=Dual-=Dual-Atrium Atrium and and VentricleVentricle

OO=none=none

AA=Atrium=Atrium

VV=Ventricl=Ventriclee

DD=Dual-=Dual-Atrium and Atrium and VentricleVentricle

OO=none=none

TT=Trigger=Triggereded

II=Inhibite=Inhibitedd

DD=Dual-=Dual-Triggered Triggered and and InhibitedInhibited

OO=none=none

RR=Rate =Rate modulationmodulation

OO=none=none

AA=Atriu=Atriumm

VV=Ventri=Ventriclecle

DD=Dual-=Dual-Atrium Atrium and and VentricleVentricle

NASPE/BPEG 2002

DDD

Indications for Pacing for AV BlockDegreeDegree Pacemaker necessaryPacemaker necessary Pacemaker Pacemaker

probably probably necessarynecessary

Pacemaker not Pacemaker not necessarynecessary

ThirdThird Symptomatic congenital Symptomatic congenital complete heart blockcomplete heart block

Aquired symptomatic complete Aquired symptomatic complete heart blockheart block

Atrial fibrillation with complete Atrial fibrillation with complete heart blockheart block

Acquired asymptomatic Acquired asymptomatic complete heart blockcomplete heart block

SecondSecond Symptomatic type ISymptomatic type I

Symptomatic type IISymptomatic type II

Asymptomatic Asymptomatic type IItype II

Asymptomatic Asymptomatic type I at intra-His type I at intra-His or infra-His levelsor infra-His levels

Asymptomatic type Asymptomatic type I at supra-His (AV I at supra-His (AV nodal) blocknodal) block

FirstFirst Asymptomatic or Asymptomatic or symptomaticsymptomatic

Indications for Pacing for Sinus Node Dysfunction

PacemakerPacemaker Pacemaker probably Pacemaker probably necessarynecessary

Pacemaker not Pacemaker not necessarynecessary

Symptomatic bradycardiaSymptomatic bradycardia Symptomatic patients with Symptomatic patients with sinus node dysfunction sinus node dysfunction with documented rates of with documented rates of <40 bpm without a clear-<40 bpm without a clear-cut association between cut association between significant symptoms and significant symptoms and the bradycardiathe bradycardia

Asymptomatic sinus node Asymptomatic sinus node dysfunctiondysfunction

Symptomatic sinus Symptomatic sinus bradycardia due to long-bradycardia due to long-term drug therapy of a term drug therapy of a type and dose for which type and dose for which there is no accepted there is no accepted alternativealternative

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/

cryosurgery– External defibrillators– Therapeutic radiation

• Nonmedical– Arc welding

equipment– Automobile engines– Radar Transmitters

Biventricular Pacing

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

Sinusnode

AVnode

Cardiomyopathy, LBBB, Heart Failure

Sinus node

AVnode

• Delayed lateral wall contraction

• Disorganized ventricular contraction

• Decreased pumping efficiency

Conduction block

Heart FailureBifocal Ventricular Pacing

Sinus node

AVnode

• Intraventricular Activation • Organized ventricular

activation sequence• Coordinated septal and

free-wall contraction• Improved pumping

efficiency

Stimulation therapy

Conduction block

Bi-Ventricular Pacing

Coronary sinus lead

Right atrial lead

Right ventricular lead

N Engl J Med 2003

LV lead

RV coil

SVC coil

RA lead

LV lead

RV lead

RA 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, 2007Ellenbogen 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 implantationB. 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 AlgorithmIf Non –Ischemic Dilated Cardiomyopathy:

If LVEF ≤ 35%, CHF Class III-IV, QRS≤ 35%, CHF Class III-IV, QRS ≥ 120 ms≥ 120 ms

ICD

ACE inhibitors, Beta Blockers

& EF ≤ 35%≤ 35%

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