title: Early repolarization in an ambulatory clinical population.
abstract: BACKGROUND
  The significance of early repolarization, particularly regarding the morphology of the R-wave downslope, has come under question.
  
  
  RESULTS
  We evaluated 29 281 resting ambulatory ECGs from the VA Palo Alto Health Care System. With PR interval as the isoelectric line and amplitude criteria ≥0.1 mV, ST-segment elevation is defined at the end of the QRS, J wave as an upward deflection, and slur as a conduction delay on the QRS downstroke. Associations of ST-segment elevation patterns, J waves, and slurs with cardiovascular mortality were analyzed with Cox analysis. With a median follow-up of 7.6 years, there were 1995 cardiac deaths. Of 29 281 subjects, 87% were male (55±14 years) and 13% were female (56±17 years); 13% were black, 6% were Hispanic, and 81% were white or other. Six hundred sixty-four (2.3%) had inferior or lateral ST-segment elevation: 185 (0.6%) in inferior leads and 479 (1.6%) in lateral leads, 163 (0.6%) in both, and 0.4% had global elevation. A total of 4041 ECGs were analyzed with enhanced display, and 583 (14%) had J waves or slurring, which were more prevalent in those with than in those without ST-segment elevation (61% versus 13%; P<0.001). ST-segment elevation occurred more in those with than in those without J waves or slurs (12% versus 1.3%; P<0.001). Except when involving only inferior leads, all components of early repolarization were more common in young individuals, male subjects, blacks, and those with bradycardia. All patterns and components of early repolarization were associated with decreased cardiovascular mortality, but this was not significant after adjustment for age.
  
  
  CONCLUSIONS
  We found no significant association between any components of early repolarization and cardiac mortality.
authors: Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, CA, USA. manu.uberoi@gmail.com
authors: Abhimanyu
authors: A
authors: Uberoi
authors: Nikhil A
authors: NA
authors: Jain
authors: Marco
authors: M
authors: Perez
authors: Anthony
authors: A
authors: Weinkopff
authors: Euan
authors: E
authors: Ashley
authors: David
authors: D
authors: Hadley
authors: Mintu P
authors: MP
authors: Turakhia
authors: Victor
authors: V
authors: Froelicher
mesh_terms: D000328:Adult; D000368:Aged; D000553:Ambulatory Care / Q000379:methods; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors