aicd in asian settings ppt

AICD in Asian settings

Dr.Micheal Mirowski(1924-90)

1980 First human implant1985 FDA approval of first ICD for market release1992 Nonthoracotomy lead system (investigational)1993 Biphasic ICD system/tiered (FDA approved)1993 Pectoral implant (investigational)1995 Pectoral unipolar system (FDA approved) with

single lead1997 Dual chamber ICD for ventricular and atrial

arrhythmias 2012 Leadless ICD

History

Rationale behind ICD

The idea behind ICD’s recognizes that Vfib or Vtach degenerating into Vfib is responsible for a large percentage of sudden cardiac death

Sudden cardiac death

SCD- Definition

SCD is natural death from cardiac causes, heralded by abrupt loss of consciousness within 1 hour of the onset of an acute change in cardiovascular status

SCD- Perspective

50 % of all CVS deaths

>80 % due to arrhytmias esp VT/VF

Unpredictable, risk factors, forewarning symptoms not adequately defined

Commonly unexpected first event, oftenstriking victims in the productive age group

SCD - perspective

Most incidence out-of-hospital

Timely defibrillation is the only effective therapy to prevent death

Mechanism of action

Rhythm monitoring

Rhythm analysis

Delivery of therapy

Mechanism of action

Continuously moniters the electrical activity of heart

Using various sophisticated algorithms detects abnormal electrical activity and furthur classifies them into supraventricular or ventricular arrhytmia

Rate discrimination: Compares ventricular and atrial rates. If atrial>ventricular rhythm is atrial, if not its ventricular

Mechanism of action

Rhythm discrimination: Moniters how regular the ventricular tachycardia is. Usually VT is regular, AF with conduction is irregular

Morphology discrimination: checks the morphology of every ventricular beat and compares it to what the ICD believes is a normally conducted ventricular impulse for the patient. This normal ventricular impulse is often an average of a multiple of beats of the patient taken in the recent past

Mechanism of action

Once a shockable rhythm is detected(VT/VF) the ICD responds in a sequential manner which is referred to as TIERD therapy

Antitachycardia pacing(ATP): Initial response to VT. Burst of current to override the abnormal rhythm and revert to sinus rhythm. Usually terminates most of the VT’s. Not useful in VF. Is not painful

Mechanism of action Cardiovertion and Defibrillation shocks: For VT wherein

antitachycardia pacing fails, initial therapy for VF

Shocks are painful unlike antitachycardia pacing

Shock voltage depends on the preset value. Ranges from <5 J in low voltage shocks and upto 40 J in high voltage shocks

Biphasic shocks used currently

Maximum 4-5 shocks are delivered

Mechanism of action Time to shock: Usually 5-10 seconds needed to

charge the capacitors and then the shock is delivered

Rhythm reanalysis before final shock delivery to prevent unwanted shocks if arrhytmia is spontaneously terminated

Rhythm redetection: After shock delivery to look for revertion to sinus rhythym

Appropriate Detection & Effective Therapy

Sinus ----> VF ----> Defib. Shock ----> VVI (pacing) ----> Sinus

Example of Multiple Therapies

VT ----> ATP (failed) ------> Cardioversion ------> Sinus

Who should have an ICD???

According to these guys….

EVERYONE !

http://www.sjm.com/

http://www.medtronic.com/

But……

Do not think so…….

The ICD trials

The ICD trials

The landmark trials Primary prevention trials:

◦ MADIT I and II◦ MUSTT◦ SCD in HeFT◦ DEFINITE

Secondary prevention trails:

◦ AVID◦ CIDS◦ CASH

1 The AVID Investigators. N Engl J Med. 1997;337:1576-83.2 Kuck K. Circ.2000;102:748-54.3 Connolly S. Circ. 2000;101:1297-1302.

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AVID CASH CIDS1 2 3

31% 28%20%

% M

orta

lity

Red

uctio

n w

/ IC

D R

xSecondary Prevention Trials:

Reduction in Overall Mortality with ICD Therapy

3 Years 3 Years 3 Years

1 The AVID Investigators. N Engl J Med. 1997;337:1576-83.2 Kuck K. Circ.2000;102:748-54.3 Connolly S. Circ. 2000;101:1297-1302.

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20

40

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80

AVID CASH CIDS

Overall DeathArrhythmic Death

1 2 3

31%

56%

28%

59%

20%

33%

% M

orta

lity

Red

uctio

n w

/ IC

D R

xSecondary Prevention Trials:

Reduction in Mortality with ICD Therapy


Metaanalysis of secondary prevention trials

By Connolly et al

Results consistent

Overall mortality reduction being 28% with 95% CI and p-value 0.006

Almost 50% reduction in arrhytmic deaths

Metaanalysis of secondary prevention trials

Transvenous ICD showed more benefit than epicardial ICD

More benefit in advanced heart disease i.e in patients with decreased EF compared to normal EF

Above observation supported by:◦ Subgroup analysis of AVID, CIDS, CASH◦ Metaanalysis by Sheldon et al

ICD as primary prevention in ischemic cardiomyopathy:Post MI trials

1 Moss AJ. N Engl J Med. 1996;335:1933-40.2 Buxton AE. N Engl J Med. 1999;341:1882-90.3 Moss AF. N Engl J Med. 2002;346:877-83.

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80

MADIT MUSTT MADIT-II1 2 3

54% 55%

31%

Primary Prevention Post-MI Trials: Reduction in Overall Mortality with ICD Therapy

27 Months 39 Months 20 Months

% M

orta

lity

Red

uctio

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/ IC

D R

x

1 Moss AJ. N Engl J Med. 1996;335:1933-40.2 Buxton AE. N Engl J Med. 1999;341:1882-90.3 Moss AF. N Engl J Med. 2002;346:877-83.4 Moss AJ. Presented before ACC 51st Annual Scientific Sessions, Late Breaking Clinical Trials, March 19, 2002.

0

20

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60

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MADIT MUSTT MADIT-II


1 2 3, 4

54%

75%

55%

73%

31%

61%

Primary Prevention Post-MI Trials: Reduction in Mortality with ICD Therapy

27 Months 39 Months 20 Months

% M

orta

lity

Red

uctio

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/ IC

D R

x

MADIT II

MADIT II

1232 patients

Criteria◦ MI > 30 days prior◦ LVEF ≤ 30%

No longer used EPS study as criteria

Randomized to ICD or medical therapy

MADIT II

Study prematurely terminated after 20 months◦ ICD reduced all cause mortality 14.2% vs 19.8%

Showed pretty clearly that patients with Ischemic Cardiomyopathy (evidence of an MI and an LVEF of ≤ 30%) would benefit from ICD.

ICD as primary prevention In non-ishcemic cardiomyopathy

SCD in HeFt trial

Looked at pt’s w/ Heart failure from both ischemic and nonischemic causes

Enrolled 2521 patients

Class II or III Heart failure

LVEF of 35%

52% with ischemic heart failure, 48% with nonischemic cardiomyopathy.

SCD HEFT Overall

SCD HEFT Ischemic

SCD HeFT: nonischemic

SCD HEFT Conclusion

“In patients with NYHA class II or III CHF and LVEF of 35 percent or less, amiodarone has no favourable effect on survival, whereas single-lead, shock-only ICD therapy reduces overall mortality by 23 percent”

This conclusion was accurate across both ischemic and nonischemic subgroups.

Take Home Point

ICD’S can save lives in patients,in heart failure arising from BOTH ischemic AND nonischemic causes.

Defibrillators in Nonischemic cardiomyopathy therapy Evaluation trial(DEFINITE)

DEFINITE TRIAL

Take Home Point - Again

ICD’S can save lives in patients,in heart failure arising from BOTH ischemic AND nonischemic causes.

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80


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AVID CASH CIDS

1 Moss AJ. N Engl J Med. 1996;335:1933-40.2 Buxton AE. N Engl J Med. 1999;341:1882-90.3 Moss AJ. N Engl J Med. 2002;346:877-834 The AVID Investigators. N Engl J Med. 1997;337:1576-83.5 Kuck K. Circ. 2000;102:748-54.6 Connolly S. Circ. 2000:101:1297-1302.

ICD mortality reductions in primary prevention trials

are equal to or greaterthan those in secondary

prevention trials

1 2

4 65

Reductions in Overall Mortality with ICD Therapy

54% 55%

31%

27 months 39 months 20 months

31% 28%20%

% M

orta

lity

Red

uctio

n w

/ IC

D R

x%

Mor

talit

y R

educ

tion

w/ I

CD

Rx


3

0

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0

20

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AVID CASH CIDS


1 Moss AJ. N Engl J Med. 1996;335:1933-40.2 Buxton AE. N Engl J Med. 1999;341:1882-90.3 Moss AJ. N Engl J Med. 2002;346:877-834 Moss AJ. Presented before ACC 51st Annual Scientific Sessions,

Late Breaking Clinical Trials, March 19, 2002.5 The AVID Investigators. N Engl J Med. 1997;337:1576-83.6 Kuck K. Circ. 2000;102:748-54.7 Connolly S. Circ. 2000:101:1297-1302.

ICD mortality reductions in primary prevention trials

are equal to or greaterthan those in secondary

prevention trials

1 3, 42

5 76

Reductions in Mortality with ICD Therapy

54%

75%

55%

76%

31%

61%

27 months 39 months 20 months

31%

56%

28%

59%

20%

33%

% M

orta

lity

Red

uctio

n w

/ IC

D R

x%

Mor

talit

y R

educ

tion

w/ I

CD

Rx


Indications of ICD

Secondary Prevention

ICD therapy is indicated in patients who are survivors of cardiac arrest due to ventricular fibrillation or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any completely reversible causes.

ICD therapy is indicated in patients with structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable.

ICD therapy is indicated in patients with syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiological study.

III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII



All primary SCD prevention ICD recommendations apply only to patients who are receiving optimal medical therapy and have reasonable expectation of survival with good functional capacity for more than 1 year.

ICD therapy is indicated in patients with LVEF less than or equal to 35% due to prior MI who are at least 40 days post-MI and are in NYHA functional Class II or III

ICD therapy is indicated in patients with nonischemic DCM who have an LVEF less than or equal to 35% and who are in NYHA functional Class II or III

ICD therapy is indicated in patients with LV dysfunction due to prior MI who are at least 40 days post-MI, have an LVEF less than or equal to 30%, and are in NYHA functional Class I

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





All primary SCD prevention ICD recommendations apply only to patients who are receiving optimal medical therapy and have reasonable expectation of survival with good functional capacity for more than 1 year

Primary Prevention

Contraindications of ICD

ICD therapy is not indicated for patients who do not have a reasonable expectation of survival with an acceptable functional status for at least 1 year, even if they meet ICD implantation criteria specified in the Class I, IIa, and IIb recommendations above. ICD therapy is not indicated for patients with incessant VT or VF. ICD therapy is not indicated in patients with significant psychiatric illnesses that may be aggravated by device implantation or that may preclude systematic follow-up. ICD therapy is not indicated for NYHA Class IV patients with drug-refractory congestive heart failure who are not candidates for cardiac transplantation or cardiac resynchronization therapy defibrillators (CRT-D).






ICD therapy is not indicated for syncope of undetermined cause in a patient without inducible ventricular tachyarrhythmias and without structural heart disease. ICD therapy is not indicated when VF or VT is amenable to surgical or catheter ablation (e.g., atrial arrhythmias associated with the Wolff-Parkinson-White syndrome, RV or LV outflow tract VT, idiopathic VT, or fascicular VT in the absence of structural heart disease). ICD therapy is not indicated for patients with ventricular tachyarrhythmias due to a completely reversible disorder in the absence of structural heart disease (e.g., electrolyte imbalance, drugs, or trauma).





Does these indications apply in Asians?

Asian data limited

Disease pattern different from Western world

Most landmark trials seldom recruited Asian subjects

Asian data

Incidence in USA, Europe 1 per 1000 population

Similar incidence in Japan

China : 0.42 per 1000

Hong Kong: 0.0018 per 1000

SCD in Asia

In an epidemiological study in USA, it was found that Asians had a lower incidence of SCD- 212.6 per 1,00,000 compared to 407.1 in Caucasians and 502.7 in Blacks

Underlying difference for this lower incidence in Asians is not clear

SCD in Asia

Most SCD occurs in structural heart diseases ( Ischemic or non ischemic)

CAD accounts for 80% of SCD in West

CAD remains most common cause of SCD in Asia as well but incidence is quite lower compared to west

SCD in structural heart disease

South korean autopsy registrty : CAD was underlying cause of SCD in only 49.7% of cases

Japan registry of post MI patients: Incidence of SC was only 1.2% in 4 year follow up


Applicability of MADIT II, a primary prevention trial was tested in 2 Asian observational studies

Tanno et al: ◦ Japan cohort had lower incidence of SCD compared

to MADIT II cohort ( 2 versus 12.1% )

Siu et al:◦ Hongkong cohort had similar incidence of SCD

compared to MADIT II ( 10 vs 12.1% )


LVEF is most important predictor of SCD in western patients with structural heart diasease

Asian studies also showed LVEF predicts SCD

Japanese post MI registry (HIJAM II):◦ LVEF strongest predictor◦ But for similar EF SCD less common than in Western

population ( In patients with EF < 30% SCD incidence was 5.1% at 5 years compared to 12.1% at 2 years in MADIT II)


TRACE study: Incidence of SCD in patients with EF<30% was 15.5% at 3 years

VALLIANT study: Incidence of SCD in patients with EF<30% was 10% at 2 years

HIJAM II and other post MI Asian registries shows high rate of revascularization compared to Western studies, highliting importance of revascularization in preventing SCD


Less common than in structural

Mainly in young, active, previously healthy individuals

More prevalent in Asia than in West

Single centre Korean review: Of 186 SCD 44.1%had no structural heart disease

SCD in non structural heart disease

Taiwan ICD registry: In ICD implantation for secondary prevention a higher proportion of patients (23%) had structurally normal heart, as compared to Western secondary prevention trials like AVID(3%), CIDS(9%) and CASH(4%)


Common causes:◦ Brugada syndrome (Most common, far more

coomon in Asia compared to West)◦ CPVT◦ Congenital long QT syndrome◦ Short QT syndrome◦ Idiopathic VF syndrome◦ WPW syndrome


LVEF is the currently the strongest predictor for SCD

Single most important selection criteria for AICD

But, most ICD recepients for primary prevention, do not experience any VT/VF (MADIT II)

Need for other risk factors

When absolute number of SCD events were measured, majority occurred in general population group than in high risk subgroup

Current primary prevention ICD guidelines protect only a minority of SCD victims

Other available risk stratification methods like ambulatory ECG, heart rate variability, signal averaged ECG, QT dispersion and T wave alterans have poor predictive value

Need for other risk factors

Although ICD is an effective treatment for prevention of SCD, its costly, benefits only a small proportion of those at risk

Cardiac disease pattern in Asia different than in west

Asiana have lower incidence of SCD, less SCD related to CSD and more SCD related to non structural heart disease

Summary

In concordance with Western studies, LVEF remains sigle most important risk factor for SCD even in Asia,

But, for a given LVEF, the risk of SCD is considerably lower in Asia than in west

LVEF, as a sole predictor for risk stratification may not be sufficient especially in Asia

Summary

More studies needed to develop methods to risk stratify individuals at risk for SCD

Summary

aicd in asian settings ppt

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