Role Of ICD Post-MI Patients With Heart Failure

Anil Saxena 
Director & Clinical Head 
Cardiac Pacing & Electrophysiology 
Fortis Escorts Heart Institute, New Delhi INDIA 
Role Of ICD Post-MI Patients 
With Heart Failure 
VT After MI: Anatomy of Scar 
Underlying Arrhythmia of Sudden Death 
8% 
13% 
17% 62% 
Adapted from Bayés de Luna A. Am Heart J. 1989;117:151-159. 
VT 
Primary 
VF 
Torsades 
de Pointes 
Bradycardia 
Sudden Cardiac Death 
Sudden Cardiac Death 
The Chain Of Survival 
Time to Defibrillation 
• Recognize cardiac arrest 1 min 
• Activate emergency response 1 min 
• Call hospital / ambulance 1 min 
• Medical help arrives on scene 10 min 
• Locate victim and shock 2 min 
• Total Elapsed Time 15 min 
ICD: Placement 
Implantable Cardioverter 
Defibrillator 
MADIT II Trial Design 
• 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 
Consent & 
Randomisation 
Documented 
Prior MI 
LVEF <30% 
ICD No ICD 
Follow-up 
 @ 3 months 
Monitor Rx 
End Points 
Selection 
Enrolment 
Follow-up 
Results 
 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%). 
Mortality over an average follow-up of 20 months 
• 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 
No ICD (Conventional Therapy) ICD 
<0.001 0.66 (0.56-0.78) 
62% 49% 
p-value Hazard Ratio (95% CI) Cumulative Probability of Mortality (n=1232) 
Mortality over an average of 7.6 years* post-enrollment 
Additional Results – MADIT II 8-Year Data 
*median 
Circ 2010; 122: 1265-1271 
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 
Primary Prevention: 
Post-Acute MI (<40 Days), LVEF <40% 
ICD For Primary Prevention 
• Huge cost to society in view of large number of patients 
• Difficult to implement in emerging economies 
• Wrong to withhold a guideline directed therapy 
• Need to further stratify the primary prevention group to 
identify patients for 
❖ Highest benefit of ICD 
❖ Intermediate benefit of ICD 
❖ Less or no benefit of ICD 
IMPROVE-SCA STUDY 
❖ 4800 patients 100 centres global study 
❖ Prior MI, at least 40 days post MI 
❖ LVEF <35% 
❖ NYHA functional class II or III 
Presyncope/ 
Syncope 
Freq VEBs NSVT EF<25% 
Sudden Cardiac Death 
Risk Factors 
• Left Ventricular Dysfunction 
• Ventricular Ectopic Activity, NSVT 
• Wide QRS Complex 
• Reduced HR Variability 
• Positive late potentials 
• Inducible VT on EP Study 
• T wave alternance 
• Heart Rate turbulence & Baroreflex Sensitivity 
Survival After Acute MI 
Bigger JT. Am J Cardiol. 1986;57:12B. 
3 2 1 
0 
A 
B 
C 
D 
0.4 
0.6 
0.8 
1.0 
S
u
rv
iv
o
rs
h
ip
 N 
 536 
 113 
 80 
 37 
EF 
 30%
 30%
<30%
<30% 
VPD 
<10/hr
 10/hr
< 10/hr 
 10/hr 
0.2 
Yea
r 
A 
B 
C 
D 
Years After Baseline 
SCD in Relation to Complexity of VPCs 
Ruberman W. Circulation. 
1981;64(2):297-305. 
Years After Baseline 
25 
20 
15 
10 
5 
0 
0 1 2 3 4 5 
Sudden Coronary Deaths 
20 
15 
10 
5 
0 
0 1 2 3 4 5 
Other Cardiac Deaths 
Runs a/o early VPC (202) 
Other complex VPC (260) 
Simple VPC only (433) 
No VPC (844) 
25 
C
u
m
u
la
ti
v
e
 P
ro
b
a
b
ili
ty
 o
f 
D
e
a
th
(a
g
e
-a
d
ju
s
te
d
 %
) 
Normal Heart Rate Variability 
Impaired Heart Rate Variability 
Conclusions 
• Post MI ICD implantation is a standard therapy in 
selected patients with increased risk of SCD 
• There is a need to redefine the indications to 
include certain clinical situations 
• There is need to further stratify primary prevention 
population according to SCD risk 
Thank You 
anil.saxena@hotmail.com