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Electrical Storm: Managing Mayhem

Electrical Storm: Managing Mayhem. Mark A. Wood, MD CCU Conference 11.8.11. “ Electrical Storm ”. “ Electrical Storm ” defined as > 2 or > 3 VT episodes treated by ICD within a 24 hour period Electrical Storm occurs in 10 – 20% of ICD patients Important because:

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Electrical Storm: Managing Mayhem

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  1. Electrical Storm: Managing Mayhem Mark A. Wood, MD CCU Conference 11.8.11

  2. “Electrical Storm” • “Electrical Storm” defined as > 2 or > 3 VT episodes treated by ICD within a 24 hour period • Electrical Storm occurs in 10 – 20% of ICD patients • Important because: • May be immediately life threatening • Management may be difficult • May influence prognosis • Has pathophysiologic implications for VT initiation

  3. Mechanism of Electrical Storm • Name implies a dramatic departure from “normal” pattern of VT recurrences • “Normal” pattern of VT recurrences is relevant to description of electrical storm but overlooked • VT recurrences are actually clustered in time in most patients

  4. 2 detections 2 detections 4 detections Single Patient with 11 Episodes of VT Detected Over 197 Days Wood MA et al. Circulation 1995

  5. Time Between Ventricular ArrhythmiasWood et al. J Cardiovasc Electrophysiol 2005 N = 71 patients 83% episodes < 1 hour apart

  6. A Method Among Madness? The Power Law DistributionLiebovitch, Wood et al. Physical Review E 1999 730 VT detections in 31 patients PDF(t) = t -a Log PDF Log Inter-Detection Interval

  7. Long Term Patterns of Arrhythmia Recurrences • Recurrences are not randomly distributed over time • Ventricular arrhythmia recurrences described by Power Law or Weibull distributions in 85% patients • Time between arrhythmias < 1 hr for 83% inter-detection intervals

  8. Electrical Storm Electrical Storm “Real Storm” “Normal” Distribution Sprinkle?

  9. Pathophysiology of Electrical StormWhy Do Events Cluster in Time? • Transient Metabolic/Electrical states lasting hours or days • Ventricular tachycardia is proarrhythmic

  10. Cumulative Risk Pathophysiology of Arrhythmia InitiationA Confluence of Metabolic States? CRITICAL CONFLUENCE OF FACTORS - PERIOD OF HIGH PROBABILITY VT Likely VT Unlikely • TIME

  11. Pathophysiology of Arrhythmia Initiation VT is Proarrhythmic Tsuji Y et al. Circulation 2011 • Rabbit model electrical storm (CHB and ICD) • Spontaneous electrical storm associated with abnormal Ca handling • Ca abnormalities reproduced by repeated VF induction not shocks

  12. Mathematical Model of VT RecurrencesSedaghat H, Wood M • Computer model includes electrical properties of reentry circuit • Simulates months of heart beats • Spontaneous “VT” occurs due to subtle “wobble” in circuit conduction • Reentry leads to more reentry

  13. Heart Disease in Electrical Storm • Ischemic • Non-Ischemic • Valvular • Brugada’s Syndrome • Arrhythmogenic Right Ventricular Dysplasia • Infiltrative disease (Sarcoid)

  14. Clinical Causes of Electrical Storm • Unkown – approximately 66% cases • Decompensated heart failure • Acute ischemia • Metabolic disturbances • T4, K, Mg, DKA • Drug proarrhythmia • Drug overdose • Fever (DCM and Brugada’s Syndrome) • Post cardiac surgery • ICD induced • Bi V pacing or pacing induced • “Psuedo-Storm” - inappropriate therapies Approximately 33% cases

  15. Features of Electrical Storm • Occurs in secondary and primary prevention patients • Storm may be first therapies by ICD • 52 - 90% Storm events are VT, 10 – 48% VF • Time to storm averages 4 – 47 months after implant • Storms may be recurrent in same patient • Number of events 3 - 50 but extreme cases reported

  16. Door Prize Question:What is the greatest number of shocks reported during an electrical storm?

  17. The Ultimate Electrical Storm?

  18. Management of Electrical Storm:MMVT or PMVT? Momomorphic VT Think reentry Polymorphic Ventricular Tachycardia Think metabolic, drugs, ischemia, brady Ventricular Fibrillation

  19. Predictors of Electrical Storm • VT1,2 or VF 4 as indication for ICD • EF < 25%2,3 • Chronic renal failure2 • QRS >120 msec3 • Absence beta blocker therapy3 • Use of digoxin1 • Absence of revascularization after index arrhythmia1 • CAD4 • Exner et al. Circ 2001 • Brigadeau et al. EHJ 2005 • Arya et al. AJC 2006 • Verma et al. JCE 2004

  20. Management of Electrical Storm • Search for reversible causes • Acute ischemia – cath • Metabolic/Electrolyte abnormalities – labs and correct: • Magnesium – even if normal serum level • Heart failure/hypoxia: • Oxygenate • Reduce filling pressures/wall stress • Reduce sympathetics by improved hemodynamics

  21. Management of Electrical Storm Medical Therapy • Beta blockade – for ischemic heart dz • Amiodarone – widely used for everyone • Lidocaine – best for acute ischemia • Class III agents – Ibutilide off label • Class IA – procainamide, quinidine – may slow VT

  22. ICD Reprogramming • Overdrive pacing; • Prevent pause induced arrhythmias • Suppress PVCs • Inactivate proarrhythmic features • Bi V pacing • Fix sensing issues • Special algorithms • Lengthen detection time – for NSVT • Alter detection rate – For stable VT • Turn on ATP, increase first shock

  23. ICD Reprogramming

  24. Adjunctive Measures • General anesthesia • Propofol • Left stellate ganglion ablation • Emergent radiofrequency ablation

  25. Thorascopic Left Stellate Ganglion Denervation

  26. PercutaneousStellate Ganglion Blockade Abdi et al.Pain Physician 2004

  27. Rescue Ablation in Electrical StormSchreieck J et al. Heart Rhythm 2005

  28. Management of Electrical Storm Brigadeau F et al. European Heart J 2006 – 123 patients Verma et al. JCE 2004 – 208 patients • Antiarrhythmic drug therapy: 48 – 91% (Amiodarone) • No specific action – 29% • ICD reprogramming – 23% • Heart failure treatment – 16% • Ablation – 7% • Revascularization: 3 – 11% • Hyperthyroid treatment – 3%

  29. Survival After Electrical StormVerma A et al. J CardiovascElectrophysiol 2004 Death during Storm is uncommon No Storm Storm N = 208

  30. Mortality After Electrical Storm • Classification Deaths • Cardiac non-sudden: 46 - 56% • Non-cardiac: 20 - 32% • Sudden: 21% • Increased mortality after Storm likely represents failing heart Exner DV et al. Circulation 2001 and Verma A et al. J Cardiovasc Electrophysiol 2004

  31. Management After Storm • Aggressive re-vascularization • Aggressive medical therapy • Beta blockers • ACE and Aldosterone inhibitors, Statins • Antiarrhythmics • Electrolyte management • Sedation and post trauma care (PTSD)

  32. Management After Storm • Post Traumatic Stress • Poor QOL after shocks • Fear of activity/social situations • Anxiety/depression – medical Rx • Phantom Shocks/”Afraid to go to sleep” – reassurance • Request removal of device – reassurance

  33. Summary • Electrical Storm not uncommon in ICD patients • VT recurrences tend to cluster in ICD patients • Most Storms without identifiable cause but heart failure, ischemia and metabolic abnormalities should be considered • Medical management usually effective • Storm probably associated with increased subsequent mortality, aggressive management may be indicated

  34. Heard Enough?

  35. Beta Blockade for Ischemic Electrical StormNadamanee et al. Circ 2000 • 49 patients with electrical storm 10 + 11 day post MI • Electrical Storm: >20 VT/24 hours • ACLS protocol: • Lidocaine • Procainamide • Bretylium • No beta blocker • Sympathetic blockade after initial ACLS protocol

  36. LONG-TERM TEMPORAL PATTERNS OF VENTRICULAR ARRHYTHMIASWood M et al. Circulation 1995 83% of 31 patients demonstrated clustered distribution

  37. Survival After Electrical Storm Exner DV et al. Circulation 2001 • 457 AVID patients receiving ICD • Storm defined as > 3 ICD Rx/24 hours • 20% patients with Electrical Storm • 60% patients > 1 ICD therapy • Storm independent risk subsequent death RR = 2.4 (p =0.003) • In 3 months after storm RR = 5.4 (p = 0.0001) • Beyond 3 months RR = 1.9 (p = 0.04)

  38. SHIELD Study: Azimilide for VT Prevention in ICD PatientsUsing Anderson-Gill Intensity ModelDorian et al. Circulation 2004

  39. Power Law Distribution for Atrial TachyarrhythmiasShehadeh, Wood et al. JCE 2004 10,759 AT detections in 63 patients

  40. Survival After Electrical Storm Death during Storm is uncommon but No consensus on subsequent survival N = 136 Credner SC et al. JACC 1998

  41. Rescue Ablation in Electrical StormSchreieck J et al. Heart Rhythm 2005 • 5 patients ischemic cardiomyopathy • Received 3 - 310 ICD shocks in 2 weeks • 3 – 8 VT morphologies • Failed all medical and pacing therapies but allowed elctroanatomic mapping VT substrate • At ablation pace mapping and targeting delayed fractionated electrograms

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