title: A 24-hour ambulatory ecg monitoring in assessment of qt interval duration and dispersion in rowers with physiological myocardial hypertrophy.
abstract: Myocardial hypertrophy (MH) due to cardiac pathology is characterized by an increase in QT interval duration and dispersion, while the findings for exercise-induced myocardial hypertrophy are contradictory. The majority of published research findings have not explored this relationship, but there have only been a few conducted studies using 24-hour ECG monitoring. The aim of the study was to determine the QT interval duration and dispersion in short-term and 24-hour ECG in endurance athletes with myocardial hypertrophy and without it.
  
  
  METHODS
  A total of 26 well-trained rowers underwent a resting 12-lead ECG, 24-hour ECG monitoring and echocardiography.
  
  
  RESULTS
  Athletes with MH (n = 7) at rest did not show any increase in QTc interval duration and dispersion, or mean and maximal QTc duration in Holter monitoring compared to athletes without MH (n = 19). Left ventricular mass was not significantly correlated with any QTc characteristics. Furthermore, athletes with MH had significantly longer mean QT (P = 0.01) and maximal QT (P = 0.018) intervals in Holter monitoring and higher 24-hour heart rate variability indexes due to stronger vagal effects.
  
  
  CONCLUSIONS
  The present study demonstrated that athlete's heart syndrome with myocardial hypertrophy as a benign phenomenon does not lead to an increase in QT interval duration, or increases in maximal and mean duration in a 24-hour ECG. An increase in QT interval duration in athletes may have an autonomic nature.
authors.affiliation: Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia ; Kazan State Medical Academy, Kazan, Russia.
authors.forename: I Y
authors.initials: IY
authors.lastname: Lutfullin
authors.affiliation: Kazan State Medical University, Kazan, Russia.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Kim
authors.affiliation: Emergency Care Hospital of Kazan #1, Kazan, Russia.
authors.forename: R R
authors.initials: RR
authors.lastname: Bilalova
authors.affiliation: Kazan State Medical Academy, Kazan, Russia.
authors.forename: N A
authors.initials: NA
authors.lastname: Tsibulkin
authors.affiliation: Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia.
authors.forename: R R
authors.initials: RR
authors.lastname: Almetova
authors.affiliation: Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia.
authors.forename: R R
authors.initials: RR
authors.lastname: Mudarisova
authors.affiliation: Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia ; Kazan State Medical University, Kazan, Russia.
authors.forename: I I
authors.initials: II
authors.lastname: Ahmetov
keywords: Holter monitoring; QT interval; athletes; left ventricular mass; myocardial hypertrophy
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