title: Beat-to-beat spatiotemporal variability in the T vector is associated with sudden cardiac death in participants without left ventricular hypertrophy: the Atherosclerosis Risk in Communities (ARIC) Study.
abstract: BACKGROUND
  Despite advances in prevention and treatment of cardiovascular disease, sudden cardiac death (SCD) remains a clinical challenge. Risk stratification in the general population is needed.
  
  
  RESULTS
  Beat-to-beat spatiotemporal variability in the T vector was measured as the mean angle between consecutive T-wave vectors (mean TT' angle) on standard 12-lead ECGs in 14 024 participants in the Atherosclerosis Risk in Communities (ARIC) study. Subjects with left ventricular hypertrophy, atrial arrhythmias, frequent ectopy, ventricular pacing, or QRS duration ≥120 ms were excluded. The mean spatial TT' angle was 5.21±3.55°. During a median of 14 years of follow-up, 235 SCDs occurred (1.24 per 1000 person-years). After adjustment for demographics, coronary heart disease risk factors, and known ECG markers for SCD, mean TT' angle was independently associated with SCD (hazard ratio 1.089; 95% CI 1.044 to 1.137; P<0.0001). A mean TT' angle >90th percentile (>9.57°) was associated with a 2-fold increase in the hazard for SCD (hazard ratio 2.01; 95% CI 1.28 to 3.16; P=0.002). In a subgroup of patients with T-vector amplitude ≥0.2 mV, the association with SCD was almost twice as strong (hazard ratio 3.92; 95% CI 1.91 to 8.05; P<0.0001). A significant interaction between mean TT' angle and age was found: TT' angle was associated with SCD in participants aged <55 years (hazard ratio 1.096; 95% CI 0.043 to 1.152; P<0.0001) but not in participants aged ≥55 years (P(interaction)=0.009).
  
  
  CONCLUSIONS
  In a large, prospective, community-based cohort of left ventricular hypertrophy-free participants, increased beat-to-beat spatiotemporal variability in the T vector, as assessed by increasing TT' angle, was associated with SCD.
authors.affiliation: Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (J.W.W., M.E.J.).
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Waks
authors.affiliation: Epidemiological Cardiology Research Center (EPICARE), Division of Public Health Sciences and Department of Medicine, Cardiology Section, Wake Forest School of Medicine, Winston Salem, NC (E.Z.S.).
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.affiliation: Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR (C.A.H., L.G.T.).
authors.forename: Charles A
authors.initials: CA
authors.lastname: Henrikson
authors.affiliation: University of Washington, Seattle, WA (N.S., D.S.S.).
authors.forename: Nona
authors.initials: N
authors.lastname: Sotoodehnia
authors.affiliation: Whitening School of Engineering, Johns Hopkins University, Baltimore, MD (L.H.).
authors.forename: Lichy
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins School of Public Health, Baltimore, MD (S.K.A., J.C.).
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Agarwal
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (D.E.A.).
authors.forename: Dan E
authors.initials: DE
authors.lastname: Arking
authors.affiliation: University of Washington, Seattle, WA (N.S., D.S.S.) The New York Academy of Medicine, New York, NY (D.S.S.).
authors.forename: David S
authors.initials: DS
authors.lastname: Siscovick
authors.affiliation: Brigham and Women's Hospital, Harvard Medical School, Boston, MA (S.D.S.).
authors.forename: Scott D
authors.initials: SD
authors.lastname: Solomon
authors.affiliation: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (W.S.P., L.G.T.).
authors.forename: Wendy S
authors.initials: WS
authors.lastname: Post
authors.affiliation: Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (J.W.W., M.E.J.).
authors.forename: Mark E
authors.initials: ME
authors.lastname: Josephson
authors.affiliation: Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins School of Public Health, Baltimore, MD (S.K.A., J.C.).
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.affiliation: Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR (C.A.H., L.G.T.) Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (W.S.P., L.G.T.).
authors.forename: Larisa G
authors.initials: LG
authors.lastname: Tereshchenko
mesh_terms: D000367:Age Factors; D002423:Cause of Death; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D011446:Prospective Studies; D015203:Reproducibility of Results; D018570:Risk Assessment; D012737:Sex Factors
keywords: TT′ angle; atherosclerosis; electrocardiography; electrophysiology; epidemiology; sudden cardiac death