suddent cardiac death

8/10/2019 Suddent Cardiac Death

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Sudden Cardiac Death

T. Scott Wall, MD

Instructor of MedicineUniversity 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 5minutes by bystanders


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35M with a history of EtOH abuse

EF 25%

Non-sustained VT on holter monitor

History of syncope


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55M with HTN, tobacco abuse, history

of anterior wall MI 9 months ago

EF = 25% by echocardiogram


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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 andthen loses consciousness

CPR begins within 1 minute, and EMS arrives

at 6 minutes


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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 andthen 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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A Major Public Health Problem

1/2 of all

cardiacdeaths

1/7 of all

deaths


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Sudden Cardiac Arrest is one of the

Leading Causes of Death in the U.S.

0

50,000

100,000

150,000

200,000

250,000

300,000

AIDS BreastCancer

LungCancer

Stroke SCA

Source: Statistical Abstract of the U.S. 1998, Hoovers Business Press, 118th

Edition


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High CoronaryRisk

Post M I

Heart Failure/E F < 35%)

Previous

VF / VT

Syncope /Heart Disease

0 100 200 30050

(thousands)(millions)

Population Size

0 10 20 501 2 5

SCD Percent / Year Total SCD / Year

0 101 2 5 20

(percent)

Adapted from Myerburg

High Risk Groups for SCD


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Underlying Arrhythmia of

Sudden Cardiac ArrestPrimary VF

8%

Torsades de

Pointes13%

Bradycardia17%VT

62%


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Implantable Cardioverter

Defibrillator First-line therapy for patients at

risk for SCA

Small devices, pectoral implantsite

Transvenous, single incision

Local anesthesia; conscious

sedation

Short hospital stays

Few complications


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Somewhere, USA: Physicians attemptto 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 shocktherapies

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 therescuer through the

process


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AEDs Improve Survival

0

510

15

20

25

30

3540

45

50

NationalAverage

Boston, MA Settle, WA Rochester,MN

5%

24%

29%

49%


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Blame the 3rd Year

Medical Student


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Important Early ICD Trials

AVID (1997) - 2 prevention

History of VT/VF arrest

MADIT (1996) - 1 prevention with very elevated risk

Ischemic CM, EF 35%

Non-sustained VT

Inducible VT at EP study

MUSTT (1999) - 1 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 priorMI and EF < 30%

Risk reduction of

31% (p=0.016) over

average 20 monthfollow-up


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MADIT II - Conclusions

In patients with

Prior MI

EF < 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 < 35%

Randomized to ICD vs. amiodarone vs.

placebo


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Inclusion criteria

Placebo n=847 ICD implant n=829

40 months average follow- up

Optimize: B, ACE-I, Diuretics

1Bardy GH. Chapter Excerpt fromArrhythmia Treatment and Therapy. Woosley RL, Singh SN, editors. Marcel Dekker, 1stedition. 2000;323-42.

Amiodarone n=845

SCD-HeFT - Protocol


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SCD-HeFT -Results

In NYHA Class II or III HF patients with EF < 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% (p=0.007)

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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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 > 9 months, class II

or III CHF


Medicaid Services (CMS)


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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 lifeexpectancy < 1 year


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0

20,000

40,000

60,000

80,000

100,000

Owens et al

1997

Mushlin et al

1998

MADIT 1

O'Brien et al

2001

CIDS

Weiss et al

2002

$$ per life year

saved by ICD

Cost Effectiveness of ICDs


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Conclusions

Sudden cardiac death is a very importantpublic heath problem

ICD Indications have expanded substantiallyto include aggressive primary preventionapproach EF < 30-35%

Non-sustained VT

CAD/Ischemic CM

Non-ischemic CM

AED availability likely most reasonableapproach for group at low/moderate risk


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