title: Non-invasive cardiac electrophysiological indices in soccer players with mitral valve prolapse.
abstract: BACKGROUND
  Cardiac disorders constitute the most common causes of sudden cardiac death (SCD) and mitral valve prolapse (MVP) is one of the cardiac structural causes in young populations. The aim of this study was to evaluate some reliable non-invasive electrophysiological variables of SCD in young athletes with mild or moderate MVP and to compare them with their cardiorespiratory adaptations.
  
  
  METHODS
  The study population comprised of 40 amateur male soccer players, who were equally subdivided into those with (group A, aged 20.4+/-4.5 years) and without (group B, 18.4+/-2.4 years) MVP and 20 healthy age-matched sedentary individuals (group C).
  
  
  METHODS
  All subjects underwent echo study for left ventricular mass index (LVMI) estimation, treadmill spiro-ergometric test for maximal oxygen uptake (VO2max) measurement and continuous ambulatory 24-h ECG recordings for arrhythmias detection and heart rate variability (HRV) analysis. Furthermore, groups A and B were also submitted to signal-averaged electrocardiogram for late potentials (LP) assessment and to submaximal exercise test for T-wave alternans (TWA) detection.
  
  
  RESULTS
  Maximal oxygen uptake, LVMI and HRV index were enhanced in all athletes compared to group C (P<0.05). Resting QTc interval was significantly prolonged only in group B (by 3.7%) compared to C (P<0.05), whereas no significant difference was found between A and B. No positive LP or TWA were observed in all subjects. Significant correlation was found only between HRV index and VO2max in all groups.
  
  
  CONCLUSIONS
  Athletes with mild or moderate MVP do not present any significant difference in non-invasive cardiac electrophysiological indices as well as in cardiorespiratory performance, compared to healthy ones. It seems that long-term exercise induced adaptations overlap any cardiac autonomic disorders in cases of mild-to-moderate MVP severity.
authors.affiliation: Sports Medicine Laboratory, Department of Physical Education & Sport Sciences, Aristotle University of Thessaloniki, Greece. koutilan@lycos.com
authors.forename: Nikolaos A
authors.initials: NA
authors.lastname: Koutlianos
authors.forename: Evangelia J
authors.initials: EJ
authors.lastname: Kouidi
authors.forename: Thomas I
authors.initials: TI
authors.lastname: Metaxas
authors.forename: Asterios P
authors.initials: AP
authors.lastname: Deligiannis
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology*; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008945:Mitral Valve Prolapse / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000502:physiology*; D012720:Severity of Illness Index; D012916:Soccer / Q000502:physiology*