title: The prognostic value of discordant T waves in lead aVR: A simple risk marker of sudden cardiac arrest in ischemic cardiomyopathy.
abstract: BACKGROUND
  Simple and reliable ECG marker(s) for sudden cardiac arrest (SCA) could be very useful in assessing high-risk populations. Since ischemic repolarization abnormalities in the left ventricular (LV) apex are strongly correlated with discordant T waves in lead aVR, we sought to evaluate the clinical and prognostic significance of this feature in ischemic cardiomyopathy.
  
  
  METHODS
  The PAREPET trial enrolled patients with ischemic cardiomyopathy eligible for a primary prevention implantable cardiac defibrillator (ICD). Those with persistent pacing or left bundle branch block were excluded. Amplitudes of T/aVR were automatically computed from median ECG beats at enrollment and endpoints were blindly adjudicated.
  
  
  RESULTS
  The sample was mainly composed of older men (n=138, age 65±12, 91% male, EF 29±9%). At enrollment, amplitude of T/aVR significantly correlated with EF, indexed LV end-diastolic volume, B-type natriuretic peptide (BNP), regional scar volume, and PET-quantified denervated myocardium. After a median follow up of 4.2years, there were 23 (17%) adjudicated SCA. In multivariate analysis, the presence of discordant T/aVR (>0mm, n=42, 30%) was a significant and independent predictor of SCA (hazard ratio 2.0 [95% CI 1.0-4.9]) and cardiac death (hazard ratio 1.9 [95% CI 1.0-3.7]).
  
  
  CONCLUSIONS
  In subjects with ischemic cardiomyopathy, discordant T waves in lead aVR are associated with high-risk clinical parameters including lower ejection fraction, greater ventricular volume, higher BNP, and more denervated myocardium. Furthermore, discordant T/aVR remained an independent predictor of SCA and cardiovascular mortality even after accounting for these prognostic factors.
authors.affiliation: The University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: ssa33@pitt.edu.
authors.forename: Salah S
authors.initials: SS
authors.lastname: Al-Zaiti
authors.affiliation: VA WNY Health Care System at Buffalo, Buffalo, NY, USA; Clinical Translational Research Center, Buffalo, NY, USA; Department of Medicine, University at Buffalo, Buffalo, NY, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Fallavollita
authors.affiliation: VA WNY Health Care System at Buffalo, Buffalo, NY, USA; Clinical Translational Research Center, Buffalo, NY, USA; Department of Medicine, University at Buffalo, Buffalo, NY, USA; Department of Physiology & Biophysics, University at Buffalo, Buffalo, NY, USA; Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Canty
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Mary G
authors.initials: MG
authors.lastname: Carey
mesh_terms: D000368:Aged; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000401:mortality* / Q000517:prevention & control; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control; D004562:Electrocardiography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000401:mortality* / Q000517:prevention & control; D009518:New York / Q000453:epidemiology; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D015996:Survival Rate
keywords: Electrocardiogram; Lead aVR; Sudden cardiac arrest; T wave