BACKGROUND: Long QT syndrome causes ventricular tachyarrhythmias and sudden 
death. Recently, a short QT interval has also been shown to be associated with 
an increased risk of tachyarrhythmia and sudden death. However, the prevalence 
of short QT syndrome is not well-known.
HYPOTHESIS: The aim of this study was to assess the distribution of corrected QT 
intervals (QTc) and prevalence of short QT syndrome.
METHODS: This study comprised 12,149 consecutive subjects who received a 
consultation at Kanazawa University Hospital, Kanazawa, Japan, and had an 
electrocardiogram (ECG) between February 2003 and May 2004. Of these subjects, 
1,165 subjects were excluded because of inappropriate ECGs, while the remaining 
10,984 subjects had their last-recorded ECGs analyzed.
RESULTS: The QTc values showed a nearly normal distribution (408 +/- 25 
msec(1/2)), and were significantly longer in females (412 +/- 24 msec(1/2)) than 
in males (404 +/- 25 msec(1/2)) (p < 0.05). Among 5,511 males, 69 subjects 
(1.25%) exhibited QTc < 354 msec(1/2) (2 standard deviations [SDs] below the 
mean in males), and among 5,473 females, 89 subjects (1.63%) exhibited QTc < 364 
msec(1/2) (2 SDs below the mean in females). Only 3 subjects (0.03% in all 
subjects and 0.05% in males) exhibited QTc < 300 msec(1/2), however, none had 
clinical symptoms of short QT syndrome.
CONCLUSIONS: Short QT syndrome may be very rare.