title: QT dispersion and left ventricular hypertrophy in athletes: relationship with angiotensin-converting enzyme I/D polymorphism.
abstract: BACKGROUND
  QT dispersion (QTd) is a measure of inhomogeneous repolarization of myocardium and is used as an indicator of arrhythmogenicity. QTd is increased in myocardial hypertrophy secondary to systemic hypertension. The relation between left ventricular (LV) enlargement in endurance trained subjects and QTd is unknown. The cloning of the angiotensin-converting enzyme (ACE) gene has made it possible to identify a deletion (D)-insertion (I) polymorphism that appears to affect the level of serum ACE activity. The aim of this study was to assess whether physiologic left ventricular hypertrophy as a result of physical training is associated with an increased QT length or dispersion depending on ACE I/D polymorphism.
  
  
  METHODS
  56 endurance athletes and 46 sedentary subjects were included in this study, and they underwent both complete echocardiographic and electrocardiographic examination, the QT interval was measured manually as an average based on a 12-lead ECG. We also analysed ACE I and D allele frequencies in all patients.
  
  
  RESULTS
  Athletes had a significantly increased LV mass (235.1 +/- 68.5 g vs. 144.9 +/- 44.5 g, p < 0.001) and corrected QTd (QTcd) (55.5 +/- 18.1 ms vs. 42.9 +/- 17.2 ms, p < 0.001) in comparison to control subjects. There was a positive correlation between left ventricular mass index and QTcd in athletes (r = 0.3, p = 0.024). Left ventricular mass and mass index in ACE DD, DI and II genotypes were significantly different (p < 0.001). QTcd was significantly different between ACE DD (63.2 +/- 12.8 ms) and ACE II (44.9 +/- 17.6 ms) genotypes in athletes (p < 0.05).
  
  
  CONCLUSIONS
  These data show that myocardial hypertrophy induced by exercise training might be associated with increased QTd as observed in systemic hypertension and might be affected by ACE I/D polymorphism.
authors.affiliation: Department of Cardiology, Medical Faculty, Pamukkale University, Denizli, Turkey. htanriverdi@posta.pamukkale.edu.tr
authors.forename: Halil
authors.initials: H
authors.lastname: Tanriverdi
authors.forename: H Asuman
authors.initials: HA
authors.lastname: Kaftan
authors.forename: Harun
authors.initials: H
authors.lastname: Evrengul
authors.forename: Dursun
authors.initials: D
authors.lastname: Dursunoglu
authors.forename: Günfer
authors.initials: G
authors.lastname: Turgut
authors.forename: Mustafa
authors.initials: M
authors.lastname: Kiliç
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004452:Echocardiography; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005260:Female; D005838:Genotype; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000209:etiology* / Q000235:genetics; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D010807:Physical Endurance / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D012044:Regression Analysis; D013177:Sports / Q000502:physiology*
chemical_list: D007703:Peptidyl-Dipeptidase A