Primary prevention of SCD using ICD- Review of literature.pptx

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					Primary prevention of SCD using
    ICD- Review of literature
          Dr Frijo Jose A
 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
• Non-invasive evaluation for SCD
  – Cardiovascular function
  – h/o syncope
  – Ventricular arrhythmias
  – ECG
  – Autonomic function evaluation
  – Serum markers
• Invasive evaluation of SCD
  – EPS
           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
• 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
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<0.00001)

        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
          Ventricular arrhythmias
• PVC & NSVT in established SHD- risk marker of SCD-
  magnitude varies with nature & extent of underlying
• IHD- freq & repetitiveness of PVCs, + ↓ LVEF (<30%)-
  high risk of SCD (Bigger et al- Circulation 1984;69:250–
• 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)
              Standard ECG
• Prolonged QRS duration (usually ≥120 ms) and
  repolarization abn- independent predictors of
• Prolonged QTc(>420 ms, esp long-QT synd)
  and familial short-QTc (≤300 ms) indicate an
  ↑risk of SCD
     Microvolt T-wave alternans
• ABCD trial-
  – Positive & negative predictive values of MTWA
    similar to EPS at 1 year
  – MTWA & EPS have synergistic value
  – MTWA did not predict life-threatening ventricular
    tachyin 575 post-MI with LVEF <30%-but appear
    to predict all-cause mortality
• MUSTT -SAECG strong predictor of arrhy death &
  total mortality
• SAECG- excellent - predictive value in IHD, +
  predictive value is low –limits in preventive
• 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)
                 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
      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
Multicenter Automatic Defibrillator
        Implantation Trial
  (MADIT, now called MADIT-I)
• 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-95-45+50) V/S conventional medical
  therapy (n-101)
• Death from any cause- end point
•   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
• 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)
Multicenter Unsustained Tachycardia Trial
         Buxton AE. N Engl J Med 1999;341:1882-90

nThe trial was designed to study the
 concept of guiding the management of
 high risk patients with the results of EPS
nWas not primarily designed as a
 randomized ICD clinical trial
n CAD (1/12 - 3yrs)
n EF < 0.40 NYHA I,II,III
n Asymptomatic nonsustained VT
• Primary endpoint:
  – Arrhythmic death or cardiac arrest
• Median follow-up- 39/12
MUSTT EP-Guided Rx Patients
Treatment at Discharge

               No Rx                         IA
                7%                           26%

                                                          Sotalol   Drugs: 45%

   ICD                                       Amiodarone
  46%                                             10%

 Buxton AE. N Engl J Med 1999;341:1882-90.
MUSTT Randomized Patient
Results Arrhythmic Death or Cardiac Arrest
                        No EP-Guided AA Rx
                        EP-Guided Rx, (No ICD and ICD)

 Event Rate

              0.3       p = 0.04



                    0        1                   2               3           4   5
                                             Time after Enrollment (Years)

Buxton AE. N Engl J Med 1999;341:1882-90.
MUSTT Randomized Patient
                     Arrhythmic Death or Cardiac Arrest
                            EP-Guided Rx, No ICD
                            No EP-Guided AA Rx
                            EP-Guided Rx, ICD
                            p < 0.001
  Event Rate




                     0           1                2                3         4   5
                                             Time after Enrollment (Years)

Buxton AE. N Engl J Med 1999;341:1882-90.
           Relative Risk Reduction with ICD Rx (95% CI)

                        As Compared To:       As Compared To:
                         EP Guided Rx              No EP
        End               With No ICD            Guided Rx

Cardiac arrest or             76%                   73%
death from arrhythmia      (55%-87%)             (53%-85%)

Death from all causes         60%                   55%
                           (41%-73%)             (37%-68%)
•   1232 pts with a prior MI (≥1/12) & LVEF ≤0.30
•   ICD (742) V/S conventional (490)
•   Invasive EPS not required
•   End point- Death from any cause
• 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- 0.69 (P=0.016)
• As compared with conventional , ICD asso with 31%
  reduction in risk of death
          At 8 years of follow-up

• Cumulative probability of all-cause mortality -
  49% among ICD V/S 62% among non-ICD
• ICD asso with signi long-term survival benefit
  (HR- 0.66; P0.001)
ICD Benefit by Device Pacing Type
• 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
•   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)
• Median follow-up- 45.5/12
• Placebo- 244 deaths (29%), Amio - 240 (28%), ICD
  - 182 (22%)
• Placeb V/S Amio- Similar death risk (HR-
• Placeb V/S ICD- ↓ death risk of 23% (HR-
• Hence, ICD ↓overall mortality by 23%
• Results did not vary according to either ischemic
  or nonischemic causes of CHF
•   Madit 2
    - similar
•   Definite
    nyha 3
•   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- 1.07 (P-0.64)
• No evidence of improved survival among CAD
  pts + ↓LVEF + abn SAECG in whom a ICD was
  implanted prophylactically at the time of
  elective CABG
• 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
• 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-
• 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)
• 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
• 458 dcm pts with LVEF<36% and
     PVC(>10/hr) / NSVT
• 229 -medi, 229 –medi + single-chamber ICD
• Followed for mean – 29/12
• 68 deaths: 28-ICD V/S 40 med (HR-
• 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)
• 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)




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

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