Implantable Defibrillator Therapy Post Cardiac Arrest Samir Saba, MD, FACC, FHRS Associate Chief of Cardiology Director, Cardiac Electrophysiology

Disclosures Research Support: Consulting: Boston Scientific Medtronic St Jude Medical Consulting:

Outline Guidelines Secondary Prevention Trials AVID CASH CIDS Reversible Causes of Sudden cardiac Death AVID registry UPMC Data Role of the LifeVest Indications UPMC Experience Advances in ICD Therapy

Sudden Cardiac Death in the United States

Implantable Cardioverter Defibrillator Sinus Rhythm Ventricular Tachycardia 31 J

ICD Guidelines after SCA “ICD therapy is indicated in patients who are survivors of cardiac arrest due to ventricular fibrillation or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any completely reversible causes” (Class I Indication; Level of Evidence: A) ACC/AHA/HRS 2008 guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: executive summary. J Am Coll Cardiol. 2008 May 27;51(21):e1-62.

Cardiac Arrest Study Hamburg (CASH) HR=0.77, P=0.08 Kuck KH et al. Circulation 2000;102:748-54.

Canadian Implantable Defibrillator Study (CIDS) HR=0.80, P=0.14 Connolly SJ et al. Circularion 2000;1011297-1302

Antiarrhythmics Vs. Implantable Defibrillators (AVID) Trial HR=0.69, P=0.02 The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators. N Engl J Med 1997;337:1576-1584.

Patient Management After Sudden Cardiac Arrest Correct any reversible cause of SCA: Revascularization when indicated for ACS Correct electrolyte/metabolic abnormalities Discontinue medications/drugs implicated in SCA Zebras WPW Lightening/drowning/trauma

Anti-Arrhythmic Drugs After Sudden Cardiac Arrest Use of AAD is adjunctive therapy AAD Not needed as a matter of routine Reserved for patients with high burden of ectopy or NSVT May be required transiently until other triggers are reversed The choice of AAD Avoid class I agents (e.g. Flecainide, Propafenone) in patients with CAD or structural heart disease Avoid class III agents (e.g. Sotalol, Dofetilide) in patients with prolonged QT interval or renal insufficiency In the acute and subacute phases, Amiodarone is often used given that it is effective and hemodynamically tolerated Amiodarone should be avoided when possible for long term use given its potential end-organ toxicities

Ventricular Arrhythmia Ablation After Aborted Sudden Cardiac Arrest Adjunctive therapy to ICD implantation SMASH-VT trial: N=128 post MI and VT/VF Randomized 1:1 ICD ICD+RFA HR=0.35, 95% CI 0.15 to 0.78, P = 0.007 VTACH trial: N=110 post MI and stable VT with EF<50% Randomized 1:1 ICD ICD+RFA HR=0.61, 95% CI 0.37 to 0.99, P = 0.045

Reversible Correctible Causes of SCA Conceptual Concerns Determining the exact cause of a SCA and whether it is reversible is fraught with uncertainty: Reversible causes may actually be a consequence of the SCA and resuscitation efforts rather than a cause In addition, reversible and correctable causes may not be avoidable in future follow-up The occurrence of SCA in the presence of a presumed reversible cause may unveil a predisposition to electrical cardiac instability

Reversible Correctible Causes of SCA AVID Registry VF or Unstable VT Reversible Cause? No Yes AVID Registry R AVID Trial No ICD ICD

Reversible Correctible Causes of SCA UPMC Data N=646 Patients Reversible (N=435) Irreversible (N=211) Not Corrected (N=105) Corrected (N=330) ICD (N=87) No ICD (N=243) (N=31) (N=74) (N=41) (N=170) Death N=31 (36%) N=114 (47%) N=107 (63%) N=15 (37%) N=42 (57%) N=12 (39%)

Reversible Correctible Causes of SCA UPMC Data IRREVERSIBLE REVERSIBLE NOT CORRECTED REVERSIBLE CORRECTED In Acute Coronary Syndrome

Wearable Defibrillator (LifeVest) Used only as a bridge to ICD The LifeVest is indicated when there is an ICD indication but patient’s condition delays or prohibits ICD implantation Infection Neurological condition after SCA Patient /family decision Poor patient compliance

Advances in ICD Therapy Sub-Cutaneous ICD (S-ICD) Advantages: No Radiation No endocarditis No vascular occlusions No need for high risk transvenous extractions More predictable implantation times Disadvantages: No back-up pacing No ATP

Advances in ICD Therapy MRI-Conditional ICD Start of Scan EKG Pulse Ox RF Lead Heating Tissue Damage Loss of Pacing Capture Pacing Capture Threshold Change

Summary Indications for ICD implantation after aborted SCA are well established for the secondary prevention of SCD Adjunctive therapies include: AAD Ablation procedures Gaps in knowledge exist regarding managing survivors of SCA in the context of a reversible cause Recent advances in ICD technology: MRI-compatible ICD Subcutaneous ICD Home monitoring The LifeVest is only used as a bridge to ICD when ICD therapy has to be delayed in a SCA survivor

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