title: Electrocardiographic Time to Intrinsicoid Deflection and Heart Failure: The Multi-Ethnic Study of Atherosclerosis.
abstract: BACKGROUND
  Time to intrinsicoid deflection (ID), the time from onset of the QRS complex to the peak of the R wave on the electrocardiogram, represents delayed ventricular activation and suggests that impaired myocardial function is present. It is unknown whether delayed time to ID is predictive of future heart failure (HF) events.
  
  
  OBJECTIVE
  Delayed time to ID is predictive of future HF events.
  
  
  METHODS
  A total of 6394 participants (mean age, 62 ± 10 years; 54% women; 38% whites, 28% blacks, 22% Hispanics, 12% Chinese Americans) without clinically apparent cardiovascular disease or major ventricular conduction delay (QRS ≥120 ms) from the Multi-Ethnic Study of Atherosclerosis were included. Time to ID was automatically measured from baseline electrocardiograms (2000-2002) as the maximum value in leads V5 and V6 . Cox regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between time to ID and HF.
  
  
  RESULTS
  Over a median follow-up of 11.2 years, a total of 217 (3.4%) participants developed HF (incidence rate per 1000 person-years: 3.33, 95% CI: 2.91-3.80). In a multivariable Cox regression analysis adjusted for demographics, cardiovascular risk factors, and potential confounders, each 10-ms increase in maximum time to ID was associated with an increased risk for HF (HR: 1.42, 95% CI: 1.15-1.74). The results remained similar when stratified by age, sex, and race/ethnicity.
  
  
  CONCLUSIONS
  Delayed time to ID is able to identify individuals at risk for developing HF before major ventricular conduction delays (eg, bundle branch block) are evident.
authors.affiliation: Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia. wesley.oneal@emory.edu.
authors.forename: Wesley T
authors.initials: WT
authors.lastname: O'Neal
authors.affiliation: Department of Internal Medicine, Division of Cardiology, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Waqas T
authors.initials: WT
authors.lastname: Qureshi
authors.affiliation: Section for Cardiac Electrophysiology, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.affiliation: Department of Radiology, Kantonsspital Graubuenden, Chur, Switzerland.
authors.forename: Nadine
authors.initials: N
authors.lastname: Kawel-Boehm
authors.affiliation: Department of Radiology and Imaging Sciences, National Institutes of Health, Bethesda, Maryland.
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.affiliation: Department of Medicine, Division of Cardiology, and Department of Radiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.affiliation: Department of Internal Medicine, Division of Cardiology, Wake Forest School of Medicine, Winston-Salem, North Carolina.|Epidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
mesh_terms: D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000150:complications / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000208:ethnology / Q000209:etiology* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology
keywords: Electrocardiography ambulatory ECG; Epidemiology; Heart failure/cardiac transplantation/cardiomyopathy/myocarditis