title: Interatrial block during exercise tolerance tests as an additional parameter for the diagnosis of ischemic heart disease.
abstract: BACKGROUND
  Interatrial block (IAB; P-wave duration, >or=120 milliseconds) is associated with increases of left atrial pressure. We studied the use of IAB during exercise tolerance test (ETT) in diagnosis of ischemic heart disease.
  
  
  METHODS
  Exercise tolerance tests were performed in 149 patients (mean age, 50 years; male, 60.4%). P-wave duration was measured at rest, at each stage of exercise using the Bruce protocol, and in recovery. As clinically indicated, 71 patients subsequently underwent nuclear stress test and/or catheterization. The evidence of ischemia (EOI) was considered present according to the more definite test, that is, catheterization over nuclear stress test over ETT.
  
  
  RESULTS
  Among patients who did not have IAB at rest (n=115), 63 patients (54.7%) developed IAB during the ETT. The incidence of IAB during the ETT was higher in patients with EOI than patients without EOI (88.9% vs 51.9%, P=.03). When IAB during the ETT and positive ETT were used together to detect EOI, they were more accurate (86.1% vs 81.7%) than the ETT alone. Among patients with IAB at rest (n=34), patients with EOI had a higher incidence of P-wave duration increase of more than 20 milliseconds during the recovery period than patients without EOI (100% vs 21.8%, P=.015). When using P-wave duration increase of more than 20 milliseconds during the recovery period in conjunction with positive ETT, the sensitivity in detecting EOI was higher than using the ETT alone (100% vs 0%), but the specificity was worsened (68.8% vs 84.4%).
  
  
  CONCLUSIONS
  New IAB and worsening of IAB during ETT appeared in patients with ischemic heart disease and may be used as additional parameters for the ETT interpretation.
authors.affiliation: Department of Medicine, Worcester Medical Center, and Division of Cardiovascular Medicine, University of Massachusetts Medical Center, Worcester, MA 01655, USA. sirin_md@hotmail.com
authors.forename: Sirin
authors.initials: S
authors.lastname: Apiyasawat
authors.forename: Anish J
authors.initials: AJ
authors.lastname: Thomas
authors.forename: David H
authors.initials: DH
authors.lastname: Spodick
mesh_terms: D000328:Adult; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006327:Heart Block / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity