Electrical Storm: Managing Mayhem Electrical Storm: Managing Mayhem Mark A. Wood, MDMark A. Wood, MD

CCU Conference 11.8.11CCU Conference 11.8.11

““Electrical StormElectrical Storm””

““Electrical StormElectrical Storm”” defined as defined as >> 2 or 2 or >> 3 VT 3 VT episodes treated by ICD within a 24 hour periodepisodes treated by ICD within a 24 hour period

Electrical Storm occurs in 10 – 20% of ICD Electrical Storm occurs in 10 – 20% of ICD patientspatients

Important because:Important because: May be immediately life threateningMay be immediately life threatening Management may be difficultManagement may be difficult May influence prognosisMay influence prognosis Has pathophysiologic implications for VT initiationHas pathophysiologic implications for VT initiation

Mechanism of Electrical StormMechanism of Electrical Storm

Name implies a dramatic departure from Name implies a dramatic departure from ““normalnormal”” pattern of VT recurrences pattern of VT recurrences

““NormalNormal”” pattern of VT recurrences is pattern of VT recurrences is relevant to description of electrical storm relevant to description of electrical storm but overlookedbut overlooked

VT recurrences are actually clustered in VT recurrences are actually clustered in time in most patientstime in most patients

Single Patient with 11 Episodes of VT Detected Over 197 Days

Wood MA et al. Circulation 1995

4 detections

2 detections2 detections

Time Between Ventricular ArrhythmiasTime Between Ventricular ArrhythmiasWood et al. J Cardiovasc Electrophysiol 2005Wood et al. J Cardiovasc Electrophysiol 2005

N = 71 patients

83% episodes < 1 hour apart

A Method Among Madness? A Method Among Madness? The Power Law Distribution The Power Law Distribution

Liebovitch, Wood et al. Physical Review E 1999

730 VT detections

in 31 patients

Lo

g P

DF

Log Inter-Detection Interval

PDF(t) = t -a

Long Term Patterns of Long Term Patterns of Arrhythmia RecurrencesArrhythmia Recurrences

Recurrences are Recurrences are not randomlynot randomly distributed distributed over time over time

Ventricular arrhythmia recurrences Ventricular arrhythmia recurrences described by described by Power LawPower Law or or WeibullWeibull distributions in 85% patientsdistributions in 85% patients

Time between arrhythmias < 1 hr for 83% Time between arrhythmias < 1 hr for 83% inter-detection intervalsinter-detection intervals

Electrical StormElectrical Storm

Electrical Storm“Real Storm”

“Normal” Distribution

Sprinkle?

Pathophysiology of Electrical StormPathophysiology of Electrical StormWhy Do Events Cluster in Time?Why Do Events Cluster in Time?

Transient Metabolic/Electrical states Transient Metabolic/Electrical states lasting hours or days lasting hours or days

Ventricular tachycardia is proarrhythmicVentricular tachycardia is proarrhythmic

Pathophysiology of Arrhythmia InitiationPathophysiology of Arrhythmia InitiationA Confluence of Metabolic States?A Confluence of Metabolic States?

VT Unlikely

TIME

CRITICAL CONFLUENCE OF FACTORS - PERIOD OF HIGH PROBABILITY

Cumulative RiskVT Likely

Pathophysiology of Arrhythmia Initiation Pathophysiology of Arrhythmia Initiation

VT is ProarrhythmicVT is ProarrhythmicTsuji Y et al. Circulation Tsuji Y et al. Circulation

20112011 Rabbit model electrical Rabbit model electrical

storm (CHB and ICD)storm (CHB and ICD) Spontaneous electrical Spontaneous electrical

storm associated with storm associated with abnormal Ca handling abnormal Ca handling

Ca abnormalities Ca abnormalities reproduced by repeated reproduced by repeated VF induction not shocksVF induction not shocks

Mathematical Model of VT RecurrencesMathematical Model of VT RecurrencesSedaghat H, Wood M Sedaghat 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

Heart Disease in Electrical StormHeart Disease in Electrical Storm

IschemicIschemic Non-IschemicNon-Ischemic ValvularValvular BrugadaBrugada’’s Syndromes Syndrome Arrhythmogenic Right Ventricular Arrhythmogenic Right Ventricular

DysplasiaDysplasia Infiltrative disease (Sarcoid)Infiltrative disease (Sarcoid)

Clinical Causes of Electrical StormClinical Causes of Electrical Storm Unkown – approximately 66% casesUnkown – approximately 66% cases Decompensated heart failure Decompensated heart failure Acute ischemiaAcute ischemia Metabolic disturbancesMetabolic disturbances

T4, K, Mg, DKAT4, K, Mg, DKA Drug proarrhythmia Drug proarrhythmia Drug overdoseDrug overdose Fever (DCM and BrugadaFever (DCM and Brugada’’s Syndrome)s Syndrome) Post cardiac surgeryPost cardiac surgery ICD inducedICD induced

Bi V pacing or pacing inducedBi V pacing or pacing induced ““Psuedo-StormPsuedo-Storm”” - inappropriate therapies - inappropriate therapies

Approximately 33% cases

Features of Electrical StormFeatures of Electrical Storm

Occurs in secondary and primary prevention Occurs in secondary and primary prevention patientspatients

Storm may be first therapies by ICDStorm may be first therapies by ICD 52 - 90% Storm events are VT, 10 – 48% VF52 - 90% Storm events are VT, 10 – 48% VF Time to storm averages 4 – 47 months after Time to storm averages 4 – 47 months after

implantimplant Storms may be recurrent in same patientStorms may be recurrent in same patient Number of events 3 - 50 but extreme cases Number of events 3 - 50 but extreme cases

reportedreported

Door Prize Question:Door Prize Question:

What is the greatest number of What is the greatest number of shocks reported during an shocks reported during an

electrical storm?electrical storm?

The Ultimate Electrical Storm?The Ultimate Electrical Storm?

Management of Electrical Storm:Management of Electrical Storm:MMVT or PMVT?MMVT or PMVT?

Momomorphic VT

Ventricular Fibrillation

Polymorphic Ventricular Tachycardia

Think reentry

Think metabolic, drugs, ischemia, brady

Predictors of Electrical StormPredictors of Electrical Storm

VTVT1,2 1,2 or VFor VF 4 4 as indication for ICDas indication for ICD EF < 25%EF < 25%2,3 2,3

Chronic renal failureChronic renal failure22

QRS QRS >>120 msec120 msec33

Absence beta blocker therapyAbsence beta blocker therapy33

Use of digoxinUse of digoxin11

Absence of revascularization after index Absence of revascularization after index arrhythmiaarrhythmia11

CADCAD441. Exner et al. Circ 2001

2. Brigadeau et al. EHJ 2005

3. Arya et al. AJC 2006

4. Verma et al. JCE 2004

Management of Electrical StormManagement of Electrical Storm

Search for reversible causesSearch for reversible causes Acute ischemia – cath Acute ischemia – cath Metabolic/Electrolyte abnormalities – labs and Metabolic/Electrolyte abnormalities – labs and

correct:correct:• Magnesium – even if normal serum levelMagnesium – even if normal serum level

Heart failure/hypoxia:Heart failure/hypoxia:• OxygenateOxygenate• Reduce filling pressures/wall stressReduce filling pressures/wall stress• Reduce sympathetics by improved hemodynamicsReduce sympathetics by improved hemodynamics

Management of Electrical StormManagement of Electrical Storm

Medical TherapyMedical Therapy Beta blockade – for ischemic heart dzBeta blockade – for ischemic heart dz Amiodarone – widely used for everyoneAmiodarone – widely used for everyone Lidocaine – best for acute ischemiaLidocaine – best for acute ischemia Class III agents – Ibutilide off labelClass III agents – Ibutilide off label Class IA – procainamide, quinidine – may Class IA – procainamide, quinidine – may

slow VT slow VT

ICD ReprogrammingICD Reprogramming Overdrive pacing;Overdrive pacing;

Prevent pause induced arrhythmiasPrevent pause induced arrhythmias Suppress PVCsSuppress PVCs

Inactivate proarrhythmic featuresInactivate proarrhythmic features Bi V pacingBi V pacing Fix sensing issuesFix sensing issues Special algorithmsSpecial algorithms

Lengthen detection time – for NSVTLengthen detection time – for NSVT Alter detection rate – For stable VTAlter detection rate – For stable VT Turn on ATP, increase first shockTurn on ATP, increase first shock

ICD ReprogrammingICD Reprogramming

Adjunctive MeasuresAdjunctive Measures

General anesthesiaGeneral anesthesia PropofolPropofol

Left stellate ganglion Left stellate ganglion ablationablation

Emergent Emergent radiofrequency ablationradiofrequency ablation

Thorascopic Left Stellate Ganglion Thorascopic Left Stellate Ganglion DenervationDenervation

Percutaneous Stellate Ganglion Blockade Percutaneous Stellate Ganglion Blockade Abdi et al.Pain Physician 2004Abdi et al.Pain Physician 2004

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

Management of Electrical StormManagement of Electrical StormBrigadeau F et al. European Heart J 2006 – 123 patientsBrigadeau F et al. European Heart J 2006 – 123 patients

Verma et al. JCE 2004 – 208 patients

Antiarrhythmic drug therapy: 48 – 91% Antiarrhythmic drug therapy: 48 – 91% (Amiodarone)(Amiodarone)

No specific action – 29%No specific action – 29% ICD reprogramming – 23%ICD reprogramming – 23% Heart failure treatment – 16%Heart failure treatment – 16% Ablation – 7%Ablation – 7% Revascularization: 3 – 11%Revascularization: 3 – 11% Hyperthyroid treatment – 3%Hyperthyroid treatment – 3%

Survival After Electrical StormSurvival After Electrical StormVerma A et al. J Cardiovasc Electrophysiol 2004Verma A et al. J Cardiovasc Electrophysiol 2004

Death Death duringduring Storm is uncommon Storm is uncommon

No Storm

Storm

N = 208

Mortality After Electrical StormMortality After Electrical Storm

Classification DeathsClassification Deaths Cardiac non-sudden: 46 - 56%Cardiac non-sudden: 46 - 56% Non-cardiac: 20 - 32%Non-cardiac: 20 - 32% Sudden: 21%Sudden: 21%

Increased mortality after Storm likely Increased mortality after Storm likely represents failing heartrepresents failing heart

Exner DV et al. Circulation 2001 andExner DV et al. Circulation 2001 and

Verma A et al. J Cardiovasc Electrophysiol 2004Verma A et al. J Cardiovasc Electrophysiol 2004

Management After StormManagement After Storm

Aggressive re-vascularizationAggressive re-vascularization Aggressive medical therapyAggressive medical therapy

Beta blockersBeta blockers ACE and Aldosterone inhibitors, StatinsACE and Aldosterone inhibitors, Statins AntiarrhythmicsAntiarrhythmics Electrolyte managementElectrolyte management

Sedation and Sedation and post trauma care (PTSD)post trauma care (PTSD)

Management After StormManagement After Storm

Post Traumatic StressPost Traumatic Stress Poor QOL after shocksPoor QOL after shocks Fear of activity/social situationsFear of activity/social situations Anxiety/depression – medical RxAnxiety/depression – medical Rx Phantom Shocks/Phantom Shocks/””Afraid to go to sleepAfraid to go to sleep”” – –

reassurance reassurance Request removal of device – reassurance Request removal of device – reassurance

SummarySummary

Electrical Storm not uncommon in ICD patientsElectrical Storm not uncommon in ICD patients VT recurrences tend to cluster in ICD patientsVT recurrences tend to cluster in ICD patients Most Storms without identifiable cause but heart Most Storms without identifiable cause but heart

failure, ischemia and metabolic abnormalities failure, ischemia and metabolic abnormalities should be consideredshould be considered

Medical management usually effectiveMedical management usually effective Storm probably associated with increased Storm probably associated with increased

subsequent mortality, aggressive management subsequent mortality, aggressive management may be indicatedmay be indicated

Heard Enough?

Beta Blockade for Ischemic Electrical StormBeta Blockade for Ischemic Electrical StormNadamanee et al. Circ 2000Nadamanee et al. Circ 2000

49 patients with electrical 49 patients with electrical storm 10 storm 10 ++ 11 day post 11 day post MIMI

Electrical Storm: Electrical Storm: >>20 20 VT/24 hoursVT/24 hours

ACLS protocol: ACLS protocol: LidocaineLidocaine Procainamide Procainamide BretyliumBretylium No beta blockerNo beta blocker

Sympathetic blockade Sympathetic blockade after initial ACLS protocolafter initial ACLS protocol

LONG-TERM TEMPORAL PATTERNS OF LONG-TERM TEMPORAL PATTERNS OF VENTRICULAR ARRHYTHMIASVENTRICULAR ARRHYTHMIAS

Wood M et al. Circulation 1995Wood M et al. Circulation 1995

83% of 31 patients demonstrated clustered distribution

Survival After Electrical StormSurvival After Electrical StormExner DV et al. Circulation 2001Exner DV et al. Circulation 2001

457 AVID patients receiving ICD457 AVID patients receiving ICD Storm defined as Storm defined as >> 3 ICD Rx/24 hours 3 ICD Rx/24 hours 20% patients with Electrical Storm20% patients with Electrical Storm

60% patients 60% patients >> 1 ICD therapy 1 ICD therapy Storm independent risk subsequent death Storm independent risk subsequent death

RR = 2.4 (p =0.003)RR = 2.4 (p =0.003) In 3 months after storm RR = 5.4 (p = 0.0001)In 3 months after storm RR = 5.4 (p = 0.0001) Beyond 3 months RR = 1.9 (p = 0.04)Beyond 3 months RR = 1.9 (p = 0.04)

SHIELD Study: Azimilide for VT Prevention in ICD PatientsSHIELD Study: Azimilide for VT Prevention in ICD PatientsUsing Anderson-Gill Intensity ModelUsing Anderson-Gill Intensity Model

Dorian et al. Circulation 2004Dorian et al. Circulation 2004

Power Law Distribution for Atrial TachyarrhythmiasPower Law Distribution for Atrial TachyarrhythmiasShehadeh, Wood et al. JCE 2004

10,759 AT detections in 63 patients

Survival After Electrical StormSurvival After Electrical StormDeath Death duringduring Storm is uncommon but Storm is uncommon but

No consensus on subsequent survivalNo consensus on subsequent survival

N = 136

Credner SC et al. JACC 1998Credner SC et al. JACC 1998

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

5 patients ischemic cardiomyopathy5 patients ischemic cardiomyopathy Received 3 - 310 ICD shocks in 2 weeksReceived 3 - 310 ICD shocks in 2 weeks 3 – 8 VT morphologies 3 – 8 VT morphologies Failed all medical and pacing therapies but Failed all medical and pacing therapies but

allowed elctroanatomic mapping VT allowed elctroanatomic mapping VT substratesubstrate

At ablation pace mapping and targeting At ablation pace mapping and targeting delayed fractionated electrogramsdelayed fractionated electrograms