A number of sudden deaths involving young competitive athletes were reported in recent years. Sudden death among athletes is rare, but in a significant number of these cases the cause is not established and is mostly attributed to ventricular fibrillation. Physical conditioning in competitive athletes induces cardiovascular adaptation including lower resting heart rate (increased vagal tone) and increased cardiac mass (hypertrophy) and volume as a consequence of increased demand on the cardiovascular system, called "athlete's heart". Myocardial hypertrophy has been shown to cause electrophysiological remodeling where the expression of different ion channels is altered. Since the duration of repolarization depends on cycle length, the low heart rate in athletes also leads to prolonged repolarization. It is conceivable that prolonged repolarization and a possibly impaired repolarization reserve due to myocardial hypertrophy-induced downregulation of potassium currents might represent increased risk for the development of ventricular arrhythmias, including Torsades de Pointes ventricular tachycardia (TdP) that can degenerate into ventricular fibrillation and lead to sudden cardiac death in athletes. The reliable prediction of TdP remains unsatisfactory. Short-term variability (STV) of the QT interval is a novel parameter used in the assessment of arrhythmic risk. STV of repolarization can increase in case of decreased repolarization reserve even when there are no noticable changes in the duration of cardiac repolarization. STV may be significantly larger in competitive athletes and may be an early indicator of increased instability of cardiac repolarization and a higher arrhythmia propensity in this population.
|Title of host publication||Athlete Performance and Injuries|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||21|
|Publication status||Published - Feb 1 2012|
ASJC Scopus subject areas
- Social Sciences(all)