title: T-wave variability detects abnormalities in ventricular repolarization: a prospective study comparing healthy persons and Olympic athletes.
abstract: BACKGROUND
  Sudden cardiac death in athletes is more common than in the general population. Routine screening procedures are performed to identify competitors at risk. A new Holter-based parameter analyzes variation of the ventricular repolarization (TVar). The aim of this study was to evaluate differences in electrocardiogram (ECG), Echo, and Holter (H) in competitive athletes compared to a healthy control group consisting of medical students (MS).
  
  
  METHODS
  A total of 40 athletes (19 females, Olympic team, Luxembourg) and 40 MS (22 females) were examined by means of a resting ECG, treadmill exercise (TE), echocardiogram (Echo), as well as H recordings during a routine screening visit. To analyze TVar, a 20-minute H recording at rest (sampling rate 1000 per second) was performed. Moreover, heart rate variability (HRV) as well as HR turbulence (HRT) was computed.
  
  
  RESULTS
  No differences in demographic variables were detected. Quantification of HRV detected a significant increase in the vagal component of autonomic cardiac modulation. In contrast, no differences for HRT were found. Echo parameter demonstrated a thicker septal wall without differences of the posterior wall. TVar values were normal in range, but did differ significantly between the two groups. No correlation between TVar and echo as well as Holter parameters was detected.
  
  
  CONCLUSIONS
  TVar was able to demonstrate significant differences in terms of alterations of ventricular activation. This might indicate an early change of myocardial repolarization representing a substrate for life-threatening arrhythmia. Larger studies on the predictive value of TVar including follow-up are necessary to confirm this preliminary finding.
authors.affiliation: Department of Medicine-Cardiology, University of Bonn, Bonn, Germany.
authors.forename: Lara
authors.initials: L
authors.lastname: Heinz
authors.forename: Anik
authors.initials: A
authors.lastname: Sax
authors.forename: Francois
authors.initials: F
authors.lastname: Robert
authors.forename: Axel
authors.initials: A
authors.lastname: Urhausen
authors.forename: Osman
authors.initials: O
authors.lastname: Balta
authors.forename: Jens
authors.initials: J
authors.lastname: Kreuz
authors.forename: Georg
authors.initials: G
authors.lastname: Nickenig
authors.forename: Rolf
authors.initials: R
authors.lastname: Ocklenburg
authors.forename: Joerg O
authors.initials: JO
authors.lastname: Schwab
mesh_terms: D016022:Case-Control Studies; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D013550:Swimming / Q000502:physiology*; D055815:Young Adult