title: Exercise-Induced Repolarization Changes in Patients with Isolated Myocardial Bridging.
abstract: BACKGROUND
  Although myocardial bridging (MB) is defined as an angiographic phenomenon with a benign course, it has also been associated with adverse cardiovascular events. The effects of exercise on myocardial repolarization in patients with MB were tested in this study, with Tp-e and Tp-e/QT repolarization indexes.
  
  
  METHODS
  A total of 50 patients in whom isolated MB was diagnosed at coronary angiography (CAG) (Group I) and 48 patients with normal CAG results (Group II) were included in this study. The participants underwent treadmill exercise stress testing according to the Bruce protocol. QT dispersion (QTd) was defined as the minimum QT interval subtracted from the maximum. The Tp-e interval was defined as the difference between the QT and the QT peak time period. QTd and Tp-e intervals were calculated for all patients before and after exercise testing and differences between groups were compared.
  
  
  RESULTS
  At peak exercise, QTd and cQTd showed a significant increase in comparison to baseline values in the group of patients with myocardial bridges. Significant increases were also found with exercise in the Tp-e, cTp-e durations and Tp-e/QT ratio of the MB patient group in comparison to the baseline values. On the other hand, significant differences in QTd, cQTd, Tp-e, cTp-e intervals, and Tp-e/QT ratio during peak exercise in comparison with baseline values were not detected in the control group (p>0.05).
  
  
  CONCLUSIONS
  Significant increases in QTd, cQTd, Tp-e and cTp-e intervals and Tp-e/QT ratio were detected in the MB patients during exercise testing.
authors.affiliation: Deparment of Cardiology, Şişli Hamidiye Etfal Training and Research Hospital, İstanbul, Turkey.
authors.forename: Gökhan
authors.initials: G
authors.lastname: Aksan
authors.affiliation: Deparment of Cardiology, Aksaray State Hospital, Aksaray, Turkey.
authors.forename: Gökay
authors.initials: G
authors.lastname: Nar
authors.affiliation: Deparment of Cardiology, Aksaray State Hospital, Aksaray, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: İnci
authors.affiliation: Deparment of Cardiology, Samsun Training and Research Hospital, Samsun, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Yanık
authors.affiliation: Deparment of Cardiology, Şişli Hamidiye Etfal Training and Research Hospital, İstanbul, Turkey.
authors.forename: Kadriye Orta
authors.initials: KO
authors.lastname: Kılıçkesmez
authors.affiliation: Deparment of Cardiology, University of California, Los Angeles, CA, USA.
authors.forename: Olcay
authors.initials: O
authors.lastname: Aksoy
authors.affiliation: Deparment of Cardiology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey.
authors.forename: Korhan
authors.initials: K
authors.lastname: Soylu
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D017023:Coronary Angiography; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054084:Myocardial Bridging / Q000473:pathology* / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology; D011446:Prospective Studies