My (evidence-based) approach to post MI VT

Raja Selvaraj, JIPMER

Introduction

Not covering

  • Acute management
  • non-device management
  • non sustained VT

Covering

  • Sustained VT late after MI
    • severe LV dysfunction
    • mild LV dysfunction
  • VT/VF early after MI
    • within 48 hours
    • after 48 hours

Guidelines

  • ACC / AHA practice guidelines - 2008 (2012 update)
  • ACCF / AHA / HRS Appropriate use criteria 2013

Ventricular arrhythmias early after MI

Scenario

  • 36 male
  • VF on second day - defibrillated
  • LVEF 30%
  • No indication as per guidelines

Rationale

  • Related to reversible trigger
  • Does not affect long term outcome
  • ICD implant not indicated on this basis

Not benign !

  • AIVR - benign
  • Primary VF - poor acute outcome
  • But does not impact long term outcome

Fast MI registry - 5 year analysis of outcomes

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Higher early mortality

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Long term outcome not affected

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Appropriate use criteria

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Wearable defibrillator

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Summary

  • Aggressive short term management indicated
  • By itself not an indication for ICD implant
  • Can consider, especially with reduced EF, especially after revascularization
  • Role for wearable defibrillator

VT / VF after 48 hours

  • Secondary prevention indication
  • Need ICD implantation
  • No need to wait for secondary prevention
  • Indicator of extensive myocardial damage
  • Poor in-hospital outcome and 1 yr survival

Sustained VT late post MI

Scenario

  • 48 male
  • AWMI 4 years back
  • Presents with sustained VT / syncope / cardioversion
  • LVEF 35%

Management

  • ICD
  • Antiarrhythmic drugs / RF ablation ?
  • CAG ?
  • Single / dual chamber device?
  • Single coil / dual coil ?
  • Defibrillation threshold testing ?

ICD implantation

  • Guidelines
    • Class I A - Cardiac arrest due to VF / unstable VT
    • Class I B - Stable or unstable VT

Evidence

metaanalysis_mortality.png Ref: Connolly et al. Metaanalysis of ICD secondary prevention trials

CAG

  • Polymorphic VT / VF can be due to reversible ischemia
  • Sustained monomorphic VT not due to ischemia
  • Modest elevation of biomarkers does not indicate ischemia
  • Re test after 3 months if possibly reversible after revascularization

Anti-arrhythmic drugs

  • ICD does not prevent VT
  • ICD is not a treament for VT
  • Amiodarone reduces recurrences, low proarrhythmic risk
  • But amiodarone doesn't save lives

Ablation

  • Significant reduction in recurrences when used as first line
  • Superior to AAD with failed amio
  • Does not reduce mortality

Ablation as first line

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Ablation as first line

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Ablation after recurrence on AAD

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Ablation after recurrence on AAD

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Ablation after recurrence on AAD

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Summary

  • ICD implantation indicated
  • Need AAD / RFA to reduce recurrences
  • Amiodarone AAD of choice
  • If AAD chosen initially, RFA for recurrence

Sustained VT late post MI with mild LV dysfunction

Scenario 3

  • 54 male
  • IWMI 6 years back
  • walk-in VT
  • LVEF 45%

What do the guidelines say?

  • Hemodynamically unstable sustained VT / VF - class I A
  • Structural heart disease, stable sustained VT - class I B
  • Sustained VT with normal or near normal LV function - class IIa C

ICD secondary prevention trials metaanalysis

  • 29 implants to save one life per year of follow up
  • Benefit after 3 years?
  • Increase in survival by 1/3 years after 6 years of follow up

Importance of EF

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Beta blockers in secondary prevention

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Ref: Connolly et al. Metaanalysis of ICD secondary prevention trials

Appropriate use criteria

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Summary - My approach

  • Remote MI, severe LV dysfunction, VT/VF - ICD
  • Remote MI, moderate LV dysfunction, VT - AAD / abl, ICD
  • Reducing recurrence - AAD as first line
  • Recurrence on AAD - Ablation rather than escalate
  • Lot of grey areas, weigh evidence, involve patient in decision making