title: T-wave alternans and ST depression assessment identifies low risk individuals with ischemic cardiomyopathy in the absence of left ventricular hypertrophy.
abstract: BACKGROUND
  Although ECG left ventricular hypertrophy (LVH) by Cornell product (CP) predicts increased mortality in patients with ischemic cardiomyopathy (ICM), those without CP LVH remain at relatively high risk. We examined whether T-wave alternans (TWA) testing and ST depression can improve risk stratification in these patients.
  
  
  RESULTS
  This study examined 317 patients with ICM, nonsustained ventricular tachycardia, and a resting ECG in sinus rhythm, who presented for electrophysiology and TWA testing, and potential implantable cardioverter defibrillator (ICD) implantation. LVH was defined by CP :[(RaVL + SV3 ) +6 mm in women] × QRS duration > 2440 mm * msec. ST depression was examined as a categorical variable using an established threshold of depression of ≥50 μV in V5 or V6 . In Cox multivariate models, abnormal TWA testing and ST depression were independent predictors of mortality in patients without CP LVH (HR 2.52, CI 1.09-5.80, P = 0.030 and HR 2.87, CI 1.41-5.81, P = 0.004, respectively). Individuals with no LVH by CP, normal TWA, and no significant ST depression, comprised 23% of the study population and had a 5.6% 3-year mortality, compared to an overall 20% mortality.
  
  
  CONCLUSIONS
  TWA and ST depression testing are strong predictors of mortality among ICM patients without CP LVH, with normal testing conversely predicting low 3-year mortality. Thus, risk assessment with TWA testing and a resting ECG can identify ICM patients at low risk who may be less likely to benefit from ICD implantation.
authors.affiliation: Greenberg Division of Cardiology, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Friedman
authors.forename: Seth R
authors.initials: SR
authors.lastname: Bender
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Lerman
authors.forename: Peter M
authors.initials: PM
authors.lastname: Okin
mesh_terms: D000368:Aged; D009202:Cardiomyopathies / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D015331:Cohort Studies; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome
keywords: cardiomyopathy; electrocardiography; electrophysiology; hypertrophy