Sudden Cardiac Death

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Sudden Cardiac Death

• T. Scott Wall, MD
• Instructor of Medicine
• University of Utah

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Case Presentation 1

• 70M with HTN, prior MI
• Cardiac arrest in a Wendover casino
• CPR and shocked out of VF within 5 minutes by
  bystanders

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Case Presentation 2

• 35M with a history of EtOH abuse
• EF 25
• Non-sustained VT on holter monitor
• History of syncope

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Case Presentation 3

• 55M with HTN, tobacco abuse, history of anterior
  wall MI 9 months ago
• EF 25 by echocardiogram

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Case Presentation 4

• 43 year old female with a history of viral
  myocarditis 9 years ago
• EF 20
• On beta-blocker, ACEI therapy
• No history of atrial or ventricular arrhythmia

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Case Presentation 5

• 14 year old healthy boy
• During football he is hit in anterior chest
• Patient immediately states that he is dizzy and
  then loses consciousness
• CPR begins within 1 minute, and EMS arrives at 6
  minutes

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Sudden Cardiac Death

• American Heart Association definition
• Cardiac death occurring within one hour of the
  onset of symptoms
• According to AHA statistics, sudden death is
  responsible for
• half of all cardiac deaths
• one seventh of all deaths of Americans

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Case Presentation 5

• 14 year old healthy boy
• During football he is hit in anterior chest
• Patient immediately states that he is dizzy and
  then loses consciousness
• CPR begins within 1 minute, and EMS arrives at 6
  minutes

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QRS Impact
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Results T-wave Impact
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Sudden Cardiac DeathA Major Public Health Problem

• 1/2 of all cardiac deaths
• 1/7 of all deaths

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Sudden Cardiac Arrest is one of the Leading
Causes of Death in the U.S.
Source Statistical Abstract of the U.S. 1998,
Hoovers Business Press, 118th Edition
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High Risk Groups for SCD
Adapted from Myerburg
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Underlying Arrhythmia of Sudden Cardiac Arrest
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Implantable Cardioverter Defibrillator

• First-line therapy for patients at risk for SCA
• Small devices, pectoral implant site
• Transvenous, single incision
• Local anesthesia conscious sedation
• Short hospital stays
• Few complications

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Somewhere, USA Physicians attempt to implant
their first ICD.
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ICDs - Is there a downside?

• Risk of procedure
• Transvenous lead placement
• Procedural time 1 hour
• Complication rate 1
• Most commonly pneumothorax, infection
• Appropriate and inappropriate shock therapies
• Cost

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Automated External Defibrillator AED

• Automatically analyzes the patients heart rhythm
• Determines whether a shock is needed
• Uses voice and screen prompts to guide the
  rescuer through the process

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AEDs Improve Survival
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Important Early ICD Trials

• AVID (1997) - 2º prevention
• History of VT/VF arrest
• MADIT (1996) - 1º prevention with very elevated
  risk
• Ischemic CM, EF 35
• Non-sustained VT
• Inducible VT at EP study
• MUSTT (1999) - 1º prevention with very elevated
  risk
• Ischemic CM, EF 40
• Non-sustained VT
• Inducible VT at EP study

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MADIT II
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MADIT II
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MADIT II - Results

• ICD implant improves survival in patients with
  prior MI and EF lt 30
• Risk reduction of 31 (p0.016) over average 20
  month follow-up

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MADIT II - Conclusions

• In patients with
• Prior MI
• EF lt 30
• ICD is superior to conventional therapy

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MADIT II
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SCD-HeFT

• Symptomatic CHF (NYHA class II and III) due to
  ischemic or nonischemic dilated cardiomyopathy
• LVEF lt 35
• Randomized to ICD vs. amiodarone vs. placebo

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SCD-HeFT - Protocol
Inclusion criteria
40 months average follow- up

• Optimize ?B, ACE-I, Diuretics

1 Bardy GH. Chapter Excerpt from Arrhythmia
Treatment and Therapy. Woosley RL, Singh SN,
editors. Marcel Dekker, 1st edition. 2000323-42.
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SCD-HeFT -Results

• In NYHA Class II or III HF patients with EF lt 35
  on good background therapy, the mortality rate
  for placebo-controlled patients is 7.2 per year
  over 5 years
• Simple, shock-only ICDs decrease mortality by 23
  (p0.007)
• Amiodarone, when used as a primary preventative
  agent, does not improve survival

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Centers for Medicare Medicaid Services (CMS)

• ICD coverage decision based on MADIT II, SCD-HeFT
  finalized early 2005

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Centers for Medicare Medicaid Services (CMS)

• Documented VT/VF arrest not due to transient
  cause
• Documented familial or inherited condition
  associated with a high risk of ventricular
  arrhythmias (e.g., Long QT, HOCM)
• Prior MI, LVEF 35, NSVT, inducible VT at EP
  study
• Ischemic CM, LVEF 30
• Ischemic CM, LVEF 35 and class II or III CHF
• Non-ischemic CM, EF 35 for gt 9 months, class
  II or III CHF

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Centers for Medicare Medicaid Services (CMS)

• Patients must NOT have
• PTCA or CABG within past 3 months
• Acute MI within past 40 days
• Clinical symptoms making them candidates for
  revascularization
• Other disease (non-cardiac) with a life
  expectancy lt 1 year

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Cost Effectiveness of ICDs
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Cost Effectiveness of ICDs
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Conclusions

• Sudden cardiac death is a very important public
  heath problem
• ICD Indications have expanded substantially to
  include aggressive primary prevention approach
• EF lt 30-35
• Non-sustained VT
• CAD/Ischemic CM
• Non-ischemic CM
• AED availability likely most reasonable approach
  for group at low/moderate risk

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