Electrical Risk Stratification After STEMI

Transcription

1 Electrical Risk Stratification After STEMI Peter Cheung, MD, FACC Section of Electrophysiology, Division of Cardiology, Scott & White Clinic Texas A&M Health Science Center

2 Liew, Heart 2010; 96:

3 Define Electrical Risk Stratification I. Whether patient has a ventricular arrhythmia that is a marker for increased risk of sudden cardiac death (SCD). II. Whether there is any electrocardiographic risk stratification scheme for a patient with low EF.

4 Electrical Risk Stratification For all practical purposes, risk stratification is same whether it is STEMI or NSTEMI. Risk stratification for patient without CAD is outside the scope of this talk.

5 Epidemiology of VA & SCD Incidence of Sudden Cardiac Death General population High-risk subgroups Any prior coronary event EF<30% or heart failure Incidence Events MADIT II SCD-HeFT Cardiac arrest survivor Arrhythmia risk markers, post MI AVID, CIDS, CASH MADIT I, MUSTT Percent 0 150, ,000 Absolute Number Myerburg RJ, Kessler KM, Castellanos A. Circulation 1992;85:12-10.

6 Why do we even ask?

7 Major Implantable Cardioverter-Defibrillator Trials for Prevention of Sudden Cardiac Death Trial Year Patients (n) Inclusion Criterion: LVEF Additional Study Features Hazard Ratio* 95% CI p MADIT I < 35% NSVT and EP ( ) p=0.009 MADIT II < 30% Prior MI 0.69 ( ) p=0.016 CABG-Patch < 36% +SAECG and CABG 1.07 ( ) p=0.64 DEFINITE < 36% NICM, PVCs or NSVT 0.65 ( ) p=0.08 DINAMIT < 35% 6-40 days post-mi and Impaired HRV 1.08 ( ) p=0.66 SCD-HeFT < 35% Prior MI or NICM 0.77 ( ) p=0.007 AVID < 40% Prior cardiac Arrest, or Unstable VT 0.62 ( ) p<0.02 CASH Mean < 45% ±18 at baseline CIDS < 35% Prior cardiac Arrest, Unstable VT, or Syncope Prior cardiac arrest sided p= ( ) NS * Hazard ratios for death from any cause in the ICD group compared with the non-icd group. Includes only ICD and amiodarone patients from CASH. CI Upper Bound CI indicates Confidence Interval, EP+ = positive electrophysiologic study, HRV = heart rate variability, LVEF = left ventricular ejection fraction, MI = myocardial infarction, NICM = nonischemic cardiomyopathy, NS = Not statistically significant, NSVT = nonsustained ventricular tachycardia, PVCs = premature ventricular contractions, SAECG = signal-averaged electrocardiogram, VT = ventricular tachycardia. Epstein A, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. J Am Coll Cardiol 2008; 51:e1 62. Table 5.

8 DiMarco. NEJM 2003; 349:

9 Drugs don t prevent SCD Antiarrhythmic Drugs worse than Placebo CAST (Cardiac Arrhythmia Suppression Trial) MUSTT (Multicenter Unsustained Tachycardia Trial) ICD better than Antiarrhythmic Drugs AVID (Antiarrhythmic versus Implantable Defibrillators) CIDS (Canadian Implantable Defibrillator Study) CASH (Cardiac Arrest Study Hamburg) SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) Amiodarone no better than Placebo SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial)

10 CAST CAST Investigators, Aug 1989, NEJM

11 SCD-HeFT

12 Problems with ICD Very expensive Complications of infection, vascular injuries, inappropriate ICD shocks

13 Why Electrical Risk Stratification? Identify patients that you can do something about- ICD Avoid overtreating Expensive Complications associated with ICD Unfortunately, electrical risk stratification is more or less an academic exercise

14 Electrical Risk Stratification I. Whether patient has a ventricular arrhythmia that is a marker for increased risk of sudden cardiac death (SCD). II. Whether there is any electrocardiographic risk stratification scheme for patient with low EF.

15 What type of electrical risk marker? (> 48 hours post-mi) PVC s (CAST) NSVT & (+) EP Study (MADIT, MUSTT) VT/VF (AVID, CIDS, CASH)

16 What type of electrical risk marker? (> 48 hours post-mi) PVC s (CAST) NSVT & (+) EP Study (MADIT, MUSTT) VT/VF (AVID, CIDS, CASH)

17 . Pratt C M, Moyé L A Circulation 1995;91: Copyright American Heart Association

18 What type of electrical risk marker? (> 48 hours post-mi) PVC s (CAST) NSVT & (+) EP Study (MADIT, MUSTT) VT/VF (AVID, CIDS, CASH)

19 NSVT & (+) EP Study MADIT (Multicenter Automatic Defibrillator Implantation Trial)- prior MI (> 3wk), NSVT (> 120bpm), EF 35%, no revascularization in 3 months MUSTT (Multicenter Unsustained Tachycardia Trial)- CAD, LVEF 40%, NSVT, +EPS

20 Multicenter Unsustained Tachycardia Trial- MUSTT CAD, LVEF 40%, NSVT, +EPS

21 No statistically significant difference in the frequency or duration of spontaneous nonsustained ventricular tachycardia was seen between patients with and those without inducible sustained ventricular tachycardia.

22 What type of electrical risk marker? (> 48 hours post-mi) PVC s (CAST) NSVT & (+) EP Study (MADIT, MUSTT) VT/VF (AVID, CIDS, CASH)

23 Major Implantable Cardioverter-Defibrillator Trials for Prevention of Sudden Cardiac Death Trial Year Patients (n) Inclusion Criterion: LVEF Additional Study Features Hazard Ratio* 95% CI p MADIT I < 35% NSVT and EP ( ) p=0.009 MADIT II < 30% Prior MI 0.69 ( ) p=0.016 CABG-Patch < 36% +SAECG and CABG 1.07 ( ) p=0.64 DEFINITE < 36% NICM, PVCs or NSVT 0.65 ( ) p=0.08 DINAMIT < 35% 6-40 days post-mi and Impaired HRV 1.08 ( ) p=0.66 SCD-HeFT < 35% Prior MI or NICM 0.77 ( ) p=0.007 AVID < 40% Prior cardiac Arrest, or Unstable VT 0.62 ( ) p<0.02 CASH Mean < 45% ±18 at baseline CIDS < 35% Prior cardiac Arrest, Unstable VT, or Syncope Prior cardiac arrest sided p= ( ) NS * Hazard ratios for death from any cause in the ICD group compared with the non-icd group. Includes only ICD and amiodarone patients from CASH. CI Upper Bound CI indicates Confidence Interval, EP+ = positive electrophysiologic study, HRV = heart rate variability, LVEF = left ventricular ejection fraction, MI = myocardial infarction, NICM = nonischemic cardiomyopathy, NS = Not statistically significant, NSVT = nonsustained ventricular tachycardia, PVCs = premature ventricular contractions, SAECG = signal-averaged electrocardiogram, VT = ventricular tachycardia. Epstein A, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. J Am Coll Cardiol 2008; 51:e1 62. Table 5.

24 Electrical Risk Stratification I. Whether patient has a ventricular arrhythmia that is a marker for increased risk of sudden cardiac death (SCD). II. Whether there is any electrocardiographic risk stratification scheme for patient with low EF.

25 EKG risk markers? QRS duration- conflicting data Fragmented QRS- undetermined QT dispersion- undetermined Early repolarization- undetermined

26 Risk Stratification Tests Signal Average ECG Holter T wave alternan Electrophysiology Study None

27 Signal-Averaged ECG Ventricular Late Potentials (VLPs) Potential substrate to ventricular arrhythmia Seen in 25-50% after AMI Sensitivity 15-75% Prognostic value seems much diminished in patients who underwent revascularization.

28 Conventional Holter PVCs NSVT Low sensitivity and specificity

29 Heart rate variability SD of RR intervals Measures of cardiac autonomic tone HRV decreases with AMI Decreased HRV associated with increased mortality- Multicenter Postinfarction Study (MPS) Revascularization seems to improve HRV

30 Heart Rate Turbulence Fluctuations in sinus rhythm following PVC REFINE Study (Noninvasive Risk Assessment Early After a Myocardial Infarction)- (+) Study especially performing at weeks. ISAR-Risk Study (Improved Stratification of Autonomic Regulation for risk prediction in post-infarction patients with preserved left ventricular function)- (+)

31 Microvolt T-Wave Alternans (MTWA) MASTER (Microvolt T Wave Alternans Testing for Risk Stratification of Post-Myocardial Infarction Patients) Trial- CAD, EF < 30%, (-) patients have less event. ABCD (Alternans Before Cardioverter Defibrillator) Trial- 1 year PPV 9%, NPV 95%. Patients not immediately post-mi. Whether revascularization may affect MTWA is not studied.

32 EP Study MADIT (Multicenter Automatic Defibrillator Implantation Trial)- prior MI (> 3wk), NSVT (> 120bpm), EF 35%, no revascularization in 3 months MUSTT (Multicenter Unsustained Tachycardia Trial)

33 What clinical roles do electrical risk Not much. stratification play? Noninvasive electrophysological testing may be helpful but guidelines do not support ICD use based on it. Guidelines support invasive EP study to risk stratify patients with NSVT and EF between 35-40%. Guidelines support risk stratification by nonelectrophysiological means.

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36 Dichotomy of Approach Most clinical trials trend toward broader use of ICD AVID- history of SCD MADIT 1- NSVT, + EPS, EF 35% MUSTT- NSVT, + EPS, EF 40% MADIT 2- EF 30% SCD-HeFT- EF 35% Electrical Risk Stratification means selective (reduced) use of ICD

37 Major Implantable Cardioverter-Defibrillator Trials for Prevention of Sudden Cardiac Death Trial Year Patients (n) Inclusion Criterion: LVEF Additional Study Features Hazard Ratio* 95% CI p MADIT I < 35% NSVT and EP ( ) p=0.009 MADIT II < 30% Prior MI 0.69 ( ) p=0.016 CABG-Patch < 36% +SAECG and CABG 1.07 ( ) p=0.64 DEFINITE < 36% NICM, PVCs or NSVT 0.65 ( ) p=0.08 DINAMIT < 35% 6-40 days post-mi and Impaired HRV 1.08 ( ) p=0.66 SCD-HeFT < 35% Prior MI or NICM 0.77 ( ) p=0.007 AVID < 40% Prior cardiac Arrest, or Unstable VT 0.62 ( ) p<0.02 CASH Mean < 45% ±18 at baseline CIDS < 35% Prior cardiac Arrest, Unstable VT, or Syncope Prior cardiac arrest sided p= ( ) NS * Hazard ratios for death from any cause in the ICD group compared with the non-icd group. Includes only ICD and amiodarone patients from CASH. CI Upper Bound CI indicates Confidence Interval, EP+ = positive electrophysiologic study, HRV = heart rate variability, LVEF = left ventricular ejection fraction, MI = myocardial infarction, NICM = nonischemic cardiomyopathy, NS = Not statistically significant, NSVT = nonsustained ventricular tachycardia, PVCs = premature ventricular contractions, SAECG = signal-averaged electrocardiogram, VT = ventricular tachycardia. Epstein A, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. J Am Coll Cardiol 2008; 51:e1 62. Table 5.

38 Epidemiology of VA & SCD Incidence of Sudden Cardiac Death General population High-risk subgroups Any prior coronary event EF<30% or heart failure Incidence Events MADIT II SCD-HeFT Cardiac arrest survivor Arrhythmia risk markers, post MI AVID, CIDS, CASH MADIT I, MUSTT Percent 0 150, ,000 Absolute Number Reused with permission from Myerburg RJ, Kessler KM, Castellanos A. Circulation 1992;85:12-10.

39 ICD I IIa IIb III I IIa IIb III I IIa IIb III is indicated in patients who are survivors of cardiac arrest due to VF or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any completely reversible causes. is indicated in patients with structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable. is indicated in patients with syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at EP 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.

40 ICD I IIa IIb III I IIa IIb III I IIa IIb III I IIa IIb III is indicated in patients with LVEF 35% due to prior MI who are at least 40 days post-mi and are in NYHA functional Class II or III. is indicated in patients with nonischemic DCM who have an LVEF 35% and who are in NYHA functional Class II or III. is indicated in patients with LV dysfunction due to prior MI who are at least 40 days post-mi, have an LVEF 30%, and are in NYHA functional Class I. is indicated in patients with nonsustained VT due to prior MI, LVEF 40%, and inducible VF or sustained VT at EP 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.

41 ICD I IIaIIbIII I IIaIIbIII I IIaIIbIII I IIaIIbIII I IIaIIbIII ICD implantation is reasonable for patients with unexplained syncope, significant LV dysfunction, and nonischemic DCM. ICD implantation is reasonable for patients with sustained VT and normal or near-normal ventricular function. ICD implantation is reasonable for patients with HCM who have 1 or more major risk factors for SCD. ICD implantation is reasonable for the prevention of SCD in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) who have 1 or more risk factors for SCD. ICD implantation is reasonable to reduce SCD in patients with long-qt syndrome who are experiencing syncope and/or VT while receiving beta blockers. 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. See Section 3.2.4, Hypertrophic Cardiomyopathy, in the full-text guidelines for definition of major risk factors.

42 Defibrillator in Acute Myocardial Infarction (DINAMIT) Trial 674 patients < 40 days post-mi with LVEF 35% and decreased heart rate variability Randomized to ICD therapy (n=332) or no ICD therapy (n=342) Arrhythmic death in ICD group, but in nonarrhythmic death (6.1% per year vs. 3.5% per year, HR 1.75 (95% CI 1.11 to 2.76; p=0.016) No difference in total mortality Hohnloser SH, Kuck KH, Dorian P, et al. Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med 2004;351:

43 MI < 40days, EF 35%, decreased heart rate variability Hohnloser SH, Kuck KH, Dorian P, et al. Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med 2004;351:

44 Hohnloser SH, Kuck KH, Dorian P, et al. Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med 2004;351:

45 Defibrillator Implantation Early After Myocardial Infarction (IRIS) MI < 40days, EF 40% (± NSVT) NEJM 2009: 361:

46 IRIS NEJM 2009: 361:

47 Summary With the exception of EP Study, current guidelines neglect use of electrophysiological stratification and relies mostly on EF and NYHA. Some non-invasive electrophysiological tests may identify patients who are at lower risk of SCD. Further studies are needed. Revascularization may reverse some electrophysiological risk markers. Beware of risk stratification too early after myocardial infarction. Intervention too early after an MI does not seem to be beneficial.

48 Suggested Reading Liew, R. Prediction of sudden arrhythmic death following acute myocardial infarction. Heart 2010; 96: ACC/AHA/ESC 2006 Executive Summary. Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. ACC/AHA/HRS 2008 Executive Summary. Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities.