Défibrillateurs Implantables pour Prévenir la Mort Subite- Pour Qui et Comment? Paul Dorian, MD Hôpital St Michel, Toronto.

Défibrillateurs Implantables pour Prévenir la Mort Subite-Pour Qui et Comment?

Paul Dorian, MD

Hôpital St Michel, Toronto

Patient ER (FV spontanée)

History of the AICD

1966- Dr. M. Mirowskiconceives the idea of an implantable defibrillator after his friend, colleague and mentor Dr. Harry Heller dies of sudden cardiac deathDr. Michel MirowskiDr. Michel Mirowski

(1924-1990)(1924-1990)The Inventor of the AICDThe Inventor of the AICD

History of ICD Therapy

• 1975 - The first device is implanted and tested in an animal

• 1980 - The first patient is implanted with an AICD device

Small devices – Pectoral site Transvenous, single incision

Local anesthesia; conscious sedation

hospital stay usually 0-1 days

Few complications ( similar to pacemakers_)

Perioperative mortality < 0.5%

Programmable therapy options

Single- or dual-chamber therapy

Battery longevity up to 9 years

ICD’s Today ( 2004)

Recognizes VT and VF – 99%

Terminates VT and VF – 99%

Pacemaker

Anti-tachycardia pacing therapy

Antitachycardia Pacing (ATP)

Shock (cardioversion)

The Penalty for Failure is DeathFu Manchu

Relation between Relation between triggers triggers and substrate in SCDand substrate in SCDRelation between Relation between triggers triggers and substrate in SCDand substrate in SCD

Big Trigger Trigger Small trigger

Good EF Substrate Poor EF

IschemiaTachycardiaAdrenergic drive

NSVTlightning VPB, EAD

The substrate is DYNAMIC

Categories of ICD indications

“Secondary prophylaxis” :

Patients with a prior history of sustained VT or VFNo reversible factors ( eg acute MI)

“Primary prophylaxis” :

Patients with no history of sustained VT or VFRisk factors for sudden death - severe LV dysfunction

- Heart failure symptoms - Non sustained VT ? - inducible VT at EP study?

Number at risk:ICD: 934 715 467 273 159 104 934 715 467 273 159 104Amio: 932 664 427 248 128 82 932 664 427 248 128 82

Meta-Analysis of ICD Secondary Prevention Trials: AVID, CASH, CIDS

6543210

50

40

30

20

10

06543210

50

40

30

20

10

0

Years Years

Death Arrhythmic Death

AmioAmio

ICDICD

AmioAmio

ICDICD

Connolly et al. Eur Heart J 2000;21:2071-8

Pts with prior sustained VT or VF

Long term follow up of Patients Treated with Amiodarone in CIDS

(SMH, n=60)

Time (Years)

121086420

100

80

60

40

20

0

Freedom From Event

(%)

Mortality

Mortality or Recurrence of Arrhythmia

Mortality, Recurrence of Arrhythmia or Discontinuation of Amiodarone Due to Side Effects

Bokhari et al Circ. 2004

MUSTT Study: CAD, EF < 40% , NSVT ( > 4d post MI), inducible VT/VF

Buxton AE. N Engl J Med. 1999;341:1882-90.

Time after Enrollment (Years)

0 1 2 3 4 5

0.1

0.2

0.3

0.4

0.5

0.6

Mo

rtal

ity

Rat

e

p < 0.001

EP-Guided Rx, No ICD

No EP-Guided AA Rx

EP-Guided Rx, ICD

(17% < 1mo, 22% 1mo-1 yr post MI)

Not randomized

MADIT-II : ICD’s for patients with prior MI and EF < 30%, no prior arrhythmias

Moss AJ. NEJM 2002;346:877-83.

Defibrillator

Conventional

P = 0.007

1.0

0.9

0.8

0.7

0.6

0.0

Pro

ba

bil

ity

of

Su

rviv

al

0 1 2 3 4Year

No. at Risk

Defibrillator 742 502 (0.91) 274 (0.94) 110 (0.78) 9

Conventional 490 329 (0.90) 170 (0.78) 65 (0.69) 3

QRS Prolongation: A Strong Independent Risk Factor for Mortality in Patients with Severe Ischemic Heart disease

QRS Duration, ms

Mortality, %

<100 (n=58)

13.8

100-119 (n=86)

17.6

120-139 (n=65)

23.6

140-159 (n=44)

45.5

140 (n=60)

43.3

Kalahasti V et al, PACE 2002;24:528

Noninvasive ECG Parameters in Multivariate Cox Model for Predicting Total Mortality in MADITT II Patients Randomized to Conventional Therapy

Variable

Age ≥ 65 yearsNYHA ≥ IIBUN > 25No BB use

AFibQRS > 0.12 sec

HR

1.472.001.941.572.361.90

(95% CI)

(0.86-2.52)(1.20-3.34)(1.17-3.21)(0.94-2.66)(1.14-4.89)(1.14-3.14)

P value

0.1640.0080.0100.0890.0210.013

Zareba et al, NASPE 2002

Survival in Defibrillator Group and Conventional Treatment Group in 364 MADITT II Patients with

QRS > 0.12 sec (excluding paced patients)

MORTALITY

2-yr

36%14%

3-yr

53%21%

ConvICD

HR = 0.37 (p=0.004) 63% reduction in mortalityZareba et al NASPE 2002

SCD HeFT-Enrollment Scheme

DCM ± CAD and CHF

EF ≤ 35%

NYHA Class II or III

6 minute walk, Holter

Placebo Amiodarone ICD

R

n=847 n=845 n=829

Mortality by Intention to Treat

ICD pts – 5%/yr risk of appropriate shock

28.9%

35.8%34.1%Amiodarone vs. Placebo

ICD Therapy vs. Placebo

HR1.060.77

97.5% CI0.86, 1.300.62, 0.96

P-Value0.5290.007

No Technology is perfect

• Inappropriate shocks

• Lead fracture. Dislodgement

• Infection

• Short battery life ( 5-7 years)

• Complex programming and follow-up

• Doesn’t prevent all sudden death

ICDs in SCD-HeFT

• 2.2% not implanted

• 4.0% removed, not replaced

• 4.6% serious complications at implant, no deaths

• 9.4% serious complications in follow-up

• 5.0% appropriate shocks / pt / yr

• total: 7.4% shocks / pt / yr

CABG Patch : ICD immediately after CABG EF <35%, +ve SAECG

Bigger JT. NEJM 1997;337(22):1569-1575.

30

20

10

0

Cu

mu

lati

ve M

ort

alit

y (%

)

Month

Defibrillator Group

Control Group

p = 0.64

24%

27%

12 24 36 48

Defibrillator Gr. 446 384 313 213 61

Control Group 454 399 308 199 57

Early post MI ICD vs control: All-Cause Mortality

DINA ITDINA IT

0 6 12 18 24 30 36 42 48

0.0

0.05

0.10

0.15

0.20

0.25

Months from Randomization

Cum

ula

tive R

isk

of

Death

318 305 272 217 172 124 79 31Cntrl315 299 258 211 172 123 82 25ICD

Number at Risk

ICDControl

0 6 12 18 24 30 36 42 48

0.0

0.05

0.10

0.15

0.20

0.25

Months from Randomization

Cum

ula

tive R

isk

of

Death

318 305 272 217 172 124 79 31Cntrl315 299 258 211 172 123 82 25ICD

Number at Risk

ICDControl p=0.66

Day 6-40 post MI, EF < 35%, depressed HRV

Months

Why Don’t ICDs Save Everyone From Dying a Sudden Death?

Some patients die from CHF or MI or Asystole / PEA

Some VT / VF is a precursor to non-arrhythmic death

Some VT / VF presents as electrical storm - electrical success, but poor outcome

2437

4454

63

84

105

132

154

180

208

2.5 4 6 8 10 14 18 22 27 3138 44

31

0

50

100

150

200

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

AnnualICD

implantsper millioninhabitants

ICD Implant Rates continue to diverge between Europe and USA

MADIT & AVID

Europe

USA

MUSTT

Updated from Nisam S, 2000

MADIT II???

CANADA*

The Real Questions in Deciding on ICD Recommendation

• What is the annual risk of sudden arrhythmic death?

(or the risk / device lifetime, ~ 5 years)

• What is the annual risk of death from other causes?

All ICDs are Prophylactic

MERCI