T-wave variability detects abnormalities in ventricular repolarization: a prospective study comparing healthy persons and Olympic athletes.
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.
Heinz
Lara
L
Department of Medicine-Cardiology, University of Bonn, Bonn, Germany.
Sax
Anik
A
Robert
Francois
F
Urhausen
Axel
A
Balta
Osman
O
Kreuz
Jens
J
Nickenig
Georg
G
Ocklenburg
Rolf
R
Schwab
Joerg O
JO
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