title: Corrected QT interval as a predictor of mortality in elderly patients with syncope.
abstract: BACKGROUND
  Prolonged corrected QT interval (QTc) holds independent prognostic importance in predicting mortality in patients with coronary artery disease, diabetes mellitus and congestive heart failure. However, its association with all cause or cardiac mortality in the general population remains unclear. We evaluated the relationship between prolonged QTc and total mortality among patients with syncope.
  
  
  METHODS
  This was a retrospective study of 348 patients presenting to the emergency department with syncope of any etiology over a period of one year. All patients with atrial fibrillation, left bundle branch block and cardiac devices (pacemaker/defibrillator) were excluded. Prolonged QTc interval was defined as QTc interval ≥ 440 ms. The primary end point for this study was total mortality in patients presenting with syncope.
  
  
  RESULTS
  There were 58 (16%) deaths in this population during a mean follow-up of 30 months. Patients with prolonged QTc interval had significantly higher mortality when compared to those with normal QTc interval (22% vs 11%; p = 0.004). This significance was not retained after adjustment for covariates in the Cox regression model, where we found that age ≥ 65 years (hazard ratio [HR] 7.9; 95% confidence interval [CI] 1.9-32.9; p = 0.004) and QTc interval ≥ 500 ms (HR 3.5; 95% CI 1.56-8.12; p = 0.002) were predictors of increased mortality among patients with syncope.
  
  
  CONCLUSIONS
  In elderly patients presenting to the emergency department with syncope, QTc interval ≥ 500 ms helps identify patients at higher risk of adverse outcomes.
authors.affiliation: Department of Internal Medicine, Unity Health System, 1555 Long Pond Road, Rochester, NY 14616, USA. ashim14@gmail.com
authors.forename: Ashim
authors.initials: A
authors.lastname: Aggarwal
authors.forename: Saadia
authors.initials: S
authors.lastname: Sherazi
authors.forename: Bryana
authors.initials: B
authors.lastname: Levitan
authors.forename: Umashankar
authors.initials: U
authors.lastname: Lakshmanadoss
authors.forename: Naila
authors.initials: N
authors.lastname: Choudhary
authors.forename: Abrar
authors.initials: A
authors.lastname: Shah
authors.forename: David
authors.initials: D
authors.lastname: Hsi
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009518:New York; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013575:Syncope / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D013997:Time Factors