title: QRS fragmentation and sudden cardiac death in the obese and overweight.
abstract: BACKGROUND
  Obesity has been associated with significantly greater risk of sudden cardiac death (SCD); however, identifying the obese patient at highest risk remains a challenge. We evaluated the association between QRS fragmentation on the 12-lead electrocardiogram and SCD, in obese/overweight subjects.
  
  
  RESULTS
  In the ongoing prospective, community-based Oregon Sudden Unexpected Death Study (population approximately 1 million), we performed a case-control analysis, comparing obese/overweight SCD victims with obese/overweight controls from the same geographic region. Archived ECGs prior and unrelated to the SCD event were used for cases and all ECG measurements were assessed in blinded fashion. Fragmentation was defined as the presence of RSR' patterns and/or notching of the R/S wave in at least 2 contiguous leads. Analysis was limited to ECGs with QRS duration <120 ms. Overall prevalence of fragmentation was higher in cases (n=185; 64.9±13.8 years; 67.0% male) compared with controls (n=405; 64.9±11.0 years; 64.7% male) (34.6% versus 26.9%, P=0.06). Lateral fragmentation was significantly more frequent in cases (8.1% versus 2.5%; P<0. 01), with non-significant differences in anterior and inferior territories. Fragmentation in multiple territories (≥2) was also more likely to be observed in cases (9.7% versus 4.9%, P=0.02). In multivariable analysis with consideration of established SCD risk factors, lateral fragmentation was significantly associated with SCD (OR 2.84; 95% CI 1.01 to 8.02; P=0.05).
  
  
  CONCLUSIONS
  QRS fragmentation, especially in the lateral territory is a potential risk marker for SCD independent of the ejection fraction, among obese/overweight subjects in the general population.
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Kumar
authors.initials: K
authors.lastname: Narayanan
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.) Shanghai Jiaotong University School of Public Health, Shanghai, China (L.Z., Z.J.Z.).
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Candice
authors.initials: C
authors.lastname: Kim
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Audrey
authors.initials: A
authors.lastname: Uy-Evanado
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Carmen
authors.initials: C
authors.lastname: Teodorescu
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Kyndaron
authors.initials: K
authors.lastname: Reinier
authors.affiliation: Shanghai Jiaotong University School of Public Health, Shanghai, China (L.Z., Z.J.Z.).
authors.forename: Zhi-Jie
authors.initials: ZJ
authors.lastname: Zheng
authors.affiliation: Departments of Pathology, Oregon Health and Science University, Portland, OR (K.G.).
authors.forename: Karen
authors.initials: K
authors.lastname: Gunson
authors.affiliation: Emergency Medicine, Oregon Health and Science University, Portland, OR (J.J.).
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jui
authors.affiliation: The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (K.N., L.Z., C.K., A.U.E., C.T., K.R., S.S.C.).
authors.forename: Sumeet S
authors.initials: SS
authors.lastname: Chugh
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D016017:Odds Ratio; D009922:Oregon / Q000453:epidemiology; D050177:Overweight / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left
keywords: ECG; QRS fragmentation; obesity; sudden cardiac death