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 Lead Pacemaker Programmer 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 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 2 3 4 5 Function Chambers Paced Chambers Sensed Response to Sensing Rate Modulation Multisite pacing Specific Designations O=none A=Atrium V=Ventricle D=Dual-Atrium and Ventricle T=Triggered I=Inhibited D=Dual-Triggered and Inhibited R=Rate modulation NASPE/BPEG 2002

DDD

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

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 long-term 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/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 Sinus node AV

Cardiomyopathy, LBBB, Heart Failure Sinus node Delayed lateral wall contraction Disorganized ventricular contraction Decreased pumping efficiency AV node Conduction block

Heart Failure Bifocal Ventricular Pacing Intraventricular Activation Organized ventricular activation sequence Coordinated septal and free-wall contraction Improved pumping efficiency Sinus node AV node Stimulation therapy Conduction block

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

NYHA functional Class III or ambulatory Class IV 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 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