Aicd in asian settings ppt
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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???
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.
0
20
40
60
80
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.
0
20
40
60
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
3 Years 3 Years 3 Years
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.
0
20
40
60
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
n w
/ 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
40
60
80
MADIT MUSTT MADIT-II
Overall DeathArrhythmic Death
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
n w
/ 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.
0
20
40
60
80
MADIT MUSTT MADIT-II
0
20
40
60
80
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 Years 3 Years 3 Years
3
0
20
40
60
80
MADIT MUSTT MADIT-II
Overall DeathArrhythmic Death
0
20
40
60
80
AVID CASH CIDS
Overall DeathArrhythmic Death
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
3 Years 3 Years 3 Years
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
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
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
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
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
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).
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
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 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).
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
III IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIII IIaIIaIIa IIbIIbIIb IIIIIIIIIIIaIIaIIa IIbIIbIIb IIIIIIIII
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.
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
SCD in structural heart disease
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% )
SCD in structural heart disease
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)
SCD in structural heart disease
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
SCD in structural heart disease
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%)
SCD in non structural heart disease
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
SCD in non structural heart disease
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