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Role Of ICD Post-MI Patients
With Heart Failure

Anil Saxena
Director & Clinical Head
Cardiac Pacing & Electrophysiology
Fortis Escorts Heart Institute, New Delhi INDIA


VT After MI: Anatomy of Scar




Underlying Arrhythmia of Sudden Death

Primary
VF

8%

Torsades
de Pointes

13%

VT

Bradycardia

62%

Adapted from Bayés de Luna A. Am Heart J. 1989;117:151-159.

17%


Sudden Cardiac Death


Sudden Cardiac Death
The Chain Of Survival



Time to Defibrillation

• Recognize cardiac arrest
• Activate emergency response
• Call hospital / ambulance
• Medical help arrives on scene
• Locate victim and shock
• Total Elapsed Time

1 min

1 min
1 min

10 min
2 min

15 min


ICD: Placement


Implantable Cardioverter
Defibrillator


MADIT II Trial Design
Documented
Prior MI

Selection

LVEF <30%

Consent &
Randomisation

•
Enrolment

No ICD

ICD

Follow-up
@ 3 months

Monitor Rx

End Points

Follow-up

•

Status: Completed in 2001
First trial to show the life-saving
benefits of ICDs without
requiring patients to have a
documented history of abnormal
heart rhythms


Results
Mortality over an average follow-up of 20 months

31% reduction in the risk of death at
any interval among patients in the
defibrillator group as compared with
patients in the conventional-therapy group

The cumulative survival curves represent
a decrease in death rates in the defibrillator
group (95% confidence limits; P-value) of
12% at 1 year (27 to 40%), 28% at 2 years (4
to 46%), and 29% at 3 years (5 to 46%).

Additional Results – MADIT II 8-Year Data
Mortality over an average of 7.6 years* post-enrollment
Cumulative Probability of Mortality (n=1232)
ICD

No ICD (Conventional Therapy)

49%

62%

• 34% relative reduction in the
risk of death at any interval among
patients with a defibrillator as
compared with patients without an
ICD
• Number needed to treat (NNT)
• 8 at 8 years
• 17 at 2 years
• Analysis showed sustained benefit
with primary ICD therapy in the
MADIT II study population
*median

Circ 2010; 122: 1265-1271

Hazard Ratio (95% CI)

p-value

0.66 (0.56-0.78)

<0.001




Indications for ICD Therapy
Class I (Post MI)

• ICD therapy is indicated in patients with previous
MI and spontaneous sustained VT, whether
hemodynamically stable or unstable
(Level of Evidence: A)

❖

Prior MI

❖

Spontaneous sustained VT

❖

Hemodynamically stable or unstable


Indications for ICD Therapy

Class I (Post MI)

• ICD therapy is recommended for patients with prior
MI who are at least 40 days post-MI, have an LVEF
less than 35%, are NYHA functional class II or III.
(Level of Evidence: A)

❖

Prior MI, at least 40 days post MI

❖

LVEF <35%

❖

NYHA functional class II or III


Indications for ICD Therapy
Class I (Post MI)

• ICD therapy is recommended for patients with

prior MI who are at least 40 days post-MI, have an
LVEF less than 30%, are NYHA functional class I
(Level of Evidence: A)

❖

Prior MI, at least 40 days post MI

❖

LVEF <30%

❖

NYHA functional class I


Indications for ICD Therapy
Class I (Post MI)

• ICD therapy is indicated in patients with

nonsustained VT due to prior MI, LVEF less than or
equal to 40%, and inducible VF or sustained VT at
electrophysiological study
(Level of evidence B)
❖

Prior MI, Non-sustained VT

❖

LVEF <40%

❖

Inducible VF or sustained VT on EP study


Indications for ICD Therapy
Class I (Post MI)

• ICD therapy is indicated in patients with syncope of
undetermined origin with clinically relevant,
hemodynamically significant sustained VT or VF
induced at electrophysiological study
(Level of Evidence: B)
❖

Prior MI, history of syncope

❖

LVEF - Any EF

❖

Hemodynamically unstable VT on EP study


What Changes Could Be Done?

• More inclusions by identifying clinical situations
which cause SCD risk
❖

Less than 40 day Post MI patients with low EF

• Less liberal guidelines by better risk stratification
❖

Primary prevention population (some may not be
benefitting)


Case

• 54 year male presents with acute anterior MI
• Has sustained VT at 36 hours, DC shock given
• Revascularization NOT done/possible/available
• LVEF 25%



Secondary Prevention: CAD—VF or Hemodynamically
Unstable VT Associated With Acute (<48 h) MI
Single or Recurrent VF or
Polymorphic VT With Acute
(<48 Hours) MI

Total
revascularization
completed

No revascularization

indicated

Not amenable to
revascularization