title: T-wave reversal in the augmented unipolar right arm electrocardiographic lead is associated with increased risk of sudden death.
abstract: BACKGROUND
  Repolarization abnormalities are associated with ventricular arrhythmias, and published studies report that a reversal of T wave polarity (positive or flat T wave) in lead aVR may be linked to increased cardiovascular mortality. We evaluated whether a positive or flat T wave in aVR is a risk marker for sudden cardiac death (SCD).
  
  
  METHODS
  SCD cases from the Oregon Sudden Unexpected Death Study (catchment population ~1 million) were compared to geographic controls with coronary artery disease and no history of SCD. Archived electrocardiograms performed prior and unrelated to the SCD event were evaluated.
  
  
  RESULTS
  SCD cases (n = 691, 67.6 ± 14.9 years, 69% male) were more likely than controls (n = 663, 66.2 ± 11.6 years, 67% male) to have diabetes (40 vs 32%; p < 0.01), left ventricular ejection fraction (LVEF) ≤35% (27 vs 11 %; p < 0.01), prolonged QTc (≥450 ms; 54 vs 28%; p < 0.01) and positive (19 vs 13%; p < 0.01) or flat T wave (14 vs 7%; p < 0.01) in aVR. On multivariable analysis, a positive/flat T wave in aVR was independently associated with SCD (OR 1.9, 95% CI 1.3-2.8, p < 0.01). However, a positive T wave alone lost statistical significance in patients with LVEF ≤ 35% and QTc ≥ 450 ms. In a subgroup analysis among patients with normal LVEF, QTc, and no diabetes, a positive T wave in aVR (but not a flat T wave) remained associated with SCD (OR 2.8, 95% CI 1.2-6.1, p < 0.01).
  
  
  CONCLUSIONS
  A positive or flat T wave in lead aVR was associated with SCD in subsets of patients. This simple ECG marker in this often-ignored lead may contribute to enhancement of SCD risk stratification, and warrants further evaluation.
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Phan
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Kumar
authors.initials: K
authors.lastname: Narayanan
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Audrey
authors.initials: A
authors.lastname: Uy-Evanado
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Carmen
authors.initials: C
authors.lastname: Teodorescu
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Kyndaron
authors.initials: K
authors.lastname: Reinier
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA.
authors.forename: Harpriya
authors.initials: H
authors.lastname: Chugh
authors.affiliation: Department of Pathology, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Gunson
authors.affiliation: Department of Emergency Medicine, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jui
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, AHSP Third Floor A3100, 127 S. San Vicente Blvd, Los Angeles, CA, 90048, USA. Sumeet.Chugh@cshs.org.
authors.forename: Sumeet S
authors.initials: SS
authors.lastname: Chugh
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality*; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009922:Oregon / Q000453:epidemiology; D012307:Risk Factors; D017678:Sex Distribution; D015996:Survival Rate; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality*
keywords: Electrocardiography; Lead aVR; Risk stratification; Sudden cardiac death