BACKGROUND: Abnormally long and short QT intervals are recognized to be 
associated with an increased risk for life-threatening ventricular arrhythmias. 
It is therefore important to define the upper and lower border of the normal QT.
OBJECTIVE: The aim of this study was to describe the normal distribution of the 
QT interval in a contemporary population of young conscripts and to define long 
and short limits of the QT interval.
METHODS: In Switzerland, all young male citizens must undergo compulsory 
conscription for the Swiss Army at the age of 18 to 19 years. In every 
conscript, an electrocardiogram (ECG) is performed. Retrospectively, 41,767 
consecutive ECGs of Swiss citizens who underwent conscription for the army 
between March 1, 2004, and July 31, 2006, were analyzed.
RESULTS: The mean QTc Bazett interval was 394 +/- 22 ms. One percent of the 
conscripts had a Bazett QTc shorter than 347 ms, and one percent had a Bazett 
QTc longer than 445 ms, respectively. None of the subjects presented a QTc 
Bazett < 300 ms; the prevalence of a QTc Bazett < 320 ms was 0.02%.
CONCLUSION: The present study shows the distribution of QT intervals in an 
unselected young population. Because none of the subjects presented a QTc < 300 
ms, it may be concluded that the short QT syndrome is a very rare entity in the 
population of young male adults.