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Primary prevention of SCD using ICD- Review of literature

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Presentation on theme: "Primary prevention of SCD using ICD- Review of literature"— Presentation transcript:

1 Primary prevention of SCD using ICD- Review of literature
Dr Frijo Jose A


3 Risk stratification for ICD therapy
Incidence of SCD in unselected adult population- only 2 per 1000 p/yr Currently, LVEF- 1⁰ factor to select pts for ICD SAECG, baseline V arrhythmia, T alternans, autonomic function, EP

4 Non-invasive evaluation for SCD
Cardiovascular function h/o syncope Ventricular arrhythmias ECG Autonomic function evaluation Serum markers Invasive evaluation of SCD EPS

5 Cardiovascular function
LVEF- most consistent & powerful predictor of all-cause & cardiac mortality in IHD & DCMP NYHA- Despite subjective, imprecise- simple bedside potent risk-stratification tool Degree of NYHA class- Not linearly related NYHA classes II & III - much more likely arrhythmia than class IV



8 Pts with NYHA IV CCF- very ↑mortality from progressive pump failure
Therefore, such pts not usually considered appropriate candidates for ICD therapy Primary prevention ICD trials have excluded pts with NYHA IV

9 Pts with syncope have high risk of SCA
In CCF pts with a h/o syncope- incidence of SCD - 45%, V/S incidence 12% in pts with no h/o syncope (p< ) Middlekauff etal. Syncope in advanced heart failure: high risk of sudden death regardless of origin of syncope .J Am Coll Cardiol 1993;21:110 –116

10 Ventricular arrhythmias
PVC & NSVT in established SHD- risk marker of SCD- magnitude varies with nature & extent of underlying diseases IHD- freq & repetitiveness of PVCs, + ↓ LVEF (<30%)- high risk of SCD (Bigger et al- Circulation 1984;69:250–8) Length but not rate of NSVT- predictor of major arrhythmias in DCM 3–4 beat runs of NSVT- similar arrhythmia-free survival as pts without NSVT , but incidence of major arrhythmias ↑to 10% per yr in 10 beat runs NSVT (P<0.05). (Grimm et al- Pacing Clin Electrophysiol 2005;28:S207–10)


12 Standard ECG Prolonged QRS duration (usually ≥120 ms) and repolarization abn- independent predictors of SCD Prolonged QTc(>420 ms, esp long-QT synd) and familial short-QTc (≤300 ms) indicate an ↑risk of SCD

13 Microvolt T-wave alternans
ABCD trial- Positive & negative predictive values of MTWA similar to EPS at 1 year MTWA & EPS have synergistic value MASTER-I MTWA did not predict life-threatening ventricular tachyin 575 post-MI with LVEF <30%-but appear to predict all-cause mortality

14 SAECG MUSTT -SAECG strong predictor of arrhy death & total mortality
SAECG- excellent - predictive value in IHD, + predictive value is low –limits in preventive therapy DCM- available data conflicting- MACAS trial –abn SAECG not helpful for arrhythmic risk prediction. (Grimm et al. Marburg cardiomyopathy study. Circulation 2003;108:2883–91)

15 Serum markers BNP might be useful
521 survivors of AMI- BNP potent predictor even after adjusting for other clinical variables, inclu LVEF. (Tapanainen et al. J Am Coll Cardiol 2004;43:757–63) 121 ICD recipients with MI -↑BNP and CRP- asso ↑VT incidence. (Blangy et al. Europace 2007;9:724–9) BNP is primarily a marker of progressive CHF, which itself may lead to ↑arrhyth- role of BNP- more studies are needed

16 Invasive evaluation of SCD
IHD- inducibility of sustained V tachy during EPS- well-established marker of SCD Limitations- Relatively high number of false-negative- Non-inducibility of VT may not imply a lack of risk DCM-value of EPS- controversial

17 Multicenter Automatic Defibrillator Implantation Trial (MADIT, now called MADIT-I)

18 196 pts- NYHA- I, II, III with prior MI (≥3/52); LVEF ≤0.35; a documented asymptomatic unsustained VT; and inducible, nonsuppressible VT on EPS Sustained VT/VF reproducibly induced & not suppressed after IV procainamide CABG <2/12 or PTCA <3/12 were excluded ICD (n ) V/S conventional medical therapy (n-101) Death from any cause- end point

19 Average follow-up- 27/12 ICD- 15 Ds (11card) V/S Convnt- 39 Ds (27card) Hazard ratio for overall mortality- 0.46 Relative risk reduction of 54% with ICD


21 Subset analysis Survival benefit from ICD- only in high-risk pts
LVEF <26%, HF requiring therapy, QRS ≥ 120 Benefit ↑progressively as a function of no of risk factors- greatest reduction in mortality with ICD in those with 2 (HR 0.30) or 3 risk factors (HR 0.20)

22 MUSTT Multicenter Unsustained Tachycardia Trial Buxton AE
MUSTT Multicenter Unsustained Tachycardia Trial Buxton AE. N Engl J Med 1999;341: The trial was designed to study the concept of guiding the management of high risk patients with the results of EPS Was not primarily designed as a randomized ICD clinical trial

23 Primary endpoint: Median follow-up- 39/12 CAD (1/12 - 3yrs)
EF < 0.40 NYHA I,II,III Asymptomatic nonsustained VT Primary endpoint: Arrhythmic death or cardiac arrest Median follow-up- 39/12

24 MUSTT EP-Guided Rx Patients
Treatment at Discharge No Rx 7% ICD 46% IA 26% Sotalol 9% Amiodarone 10% Antiarrhythmic Drugs: 45% Buxton AE. N Engl J Med 1999;341: 35

25 MUSTT Randomized Patient Results Arrhythmic Death or Cardiac Arrest
0.5 No EP-Guided AA Rx EP-Guided Rx, (No ICD and ICD) p = 0.04 0.4 Event Rate 0.3 0.2 0.1 1 2 3 4 5 Time after Enrollment (Years) Buxton AE. N Engl J Med 1999;341: 17

26 MUSTT Randomized Patient Results Arrhythmic Death or Cardiac Arrest
0.5 EP-Guided Rx, No ICD No EP-Guided AA Rx EP-Guided Rx, ICD p < 0.001 0.4 Event Rate 0.3 0.2 0.1 1 2 3 4 5 Time after Enrollment (Years) Buxton AE. N Engl J Med 1999;341: 18


28 Relative Risk Reduction with ICD Rx (95% CI)
End Point As Compared To: EP Guided Rx With No ICD No EP Guided Rx Cardiac arrest or death from arrhythmia 76% (55%-87%) 73% (53%-85%) Death from all causes 60% (41%-73%) 55% (37%-68%)


30 1232 pts with a prior MI (≥1/12) & LVEF ≤0.30
NYHA-I,II,III ICD (742) V/S conventional (490) Invasive EPS not required End point- Death from any cause

31 Average follow-up- 20/12 Mortality rates- 19.8%- conventional 14.2%- ICD HR for risk of any cause death in ICD V/S conventional (P=0.016) As compared with conventional , ICD asso with 31% reduction in risk of death




35 At 8 years of follow-up Cumulative probability of all-cause mortality - 49% among ICD V/S 62% among non-ICD (P0.001) ICD asso with signi long-term survival benefit (HR- 0.66; P0.001)

36 ICD Benefit by Device Pacing Type

37 Dual-chamber ICDs were programmed to active DDD pacing in MADIT-II regardless of conduction abnormalities as at the time of the study it was hypothesized that AV sequential pacing improves CCF sympts Dual Chamber and VVI Implantable Defibrillator (DAVID) trial- high frequency of RV pacing with dual-chamber ICD- contributing factor to ↑CCF events & mortality


39 2521 pts NYHA class II (70%)or III (30%) & LVEF ≤35% IHD-52%, DCM-48% Conventional plus placebo (847) Conventional plus amiodarone (845) Conventional plus single-lead ICD (829)

40 Median follow-up- 45.5/12 Placebo- 244 deaths (29%), Amio (28%), ICD- 182 (22%) Placeb V/S Amio- Similar death risk (HR-1.06;P=0.53) Placeb V/S ICD- ↓ death risk of 23% (HR-0.77;P=0.007) Hence, ICD ↓overall mortality by 23% Results did not vary according to either ischemic or nonischemic causes of CHF


42 Madit 2- similar Definite nyha 3 best


44 Elective CABG-900 -ICD(446) or Control(454)
LVEF <0.36, and abn on SAECG Average follow- up of 32/12 ICD- 101 deaths (71cardiac), Control- 95 (72) HR for death from any cause (P-0.64)


46 No evidence of improved survival among CAD pts + ↓LVEF + abn SAECG in whom a ICD was implanted prophylactically at the time of elective CABG


48 ICD (332) V/S no ICD (342) 6-40 days after a MI LVEF ≤0.35 and impaired cardiac autonomic function (↓HR variability or ↑average 24-hr HR on Holter) mean follow-up -30/12 No diff in overall mortality betw gps Although ICD asso with ↓in the rate of death due to arrhythmia, that was offset by ↑in rate of death from nonarrhythmic causes

49 DCM

50 CAT

51 Recent onset DCM (9/12) and LVEF <30%
ICD V/S no ICD The trial was terminated after the inclusion of 104 pts because all-cause mortality rate at 1 year did not reach expected 30% in control Mean follow-up 5.5yrs- 30 deaths (13-ICD, 17-control) Cumulative survival was not significantly different between the two groups (93% and 80% in control V/S 92% and 86% in ICD after 2 and 4 yrs, resp)


53 103 DCM, LVEF <0.35, and asymptomatic NSVT - Amiodarone V/S ICD
Primary end point - total mortality Survival at 1 yr (90% vs. 96%) and 3 yrs (88% vs. 87%) in the amiodarone and ICD, respectively- not stat different (p=0.8) The study was stopped


55 458 dcm pts with LVEF<36% and
PVC(>10/hr) / NSVT NYHA I,II,III 229 -medi, 229 –medi + single-chamber ICD Followed for mean – 29/12

56 68 deaths: 28-ICD V/S 40 med (HR-0.65;P=0.08)
Statistical signi not reached, but strong trend toward ↓of mortality with ICD (p=0.08) Mortality rate 2yrs- 14.1% med V/S 7.9% ICD 17 SCD from arrhythmia: 3 ICD V/S 14 med (HR- 0.20; P=0.006)





61 NYHA IIIorIV , IHD/DCM , QRS >120ms
Optimal pharmac alone / combi with CRT with either a PPI / ICD CRT with an ICD signi reduced all-cause mortality V/S pharmac alone (HR- .50)







68 Long-QTS HCM ARVC Brugada CPVT Rec syncope on drug, sustained V arrhy
Spont sust VT, spont NSVT, f/h SCD, syncope, LV thick ≥30mm, abn BP response to exercise ARVC Induction VT in EPS, detection of NSVT on holter, male, severe RV dilation, extensive RV involvement, <5 at presentation, LV involvement, unexplained Syncope, genotypes Brugada Syncope / documented VT CPVT Syncope / documented VT on βB

69 Thank you…

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