Article
Prevalence and clinical Course of Short QT Syndrome-type ECG in Apparently Healthy Population in Japan
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Published: | February 8, 2007 |
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The short QT syndrome is a new clinical entity related with a high risk population for sudden cardiac death (SCD). Although a familial and/or congenital short QT interval patient prone to SCD or the prevalence of short QT intervals associated with ventricular fibrillation have been reported, little information is now available on the occurrence of short QT intervals in apparently healthy subjects. Thus, we sought to determine the prevalence and clinical course in healthy individuals exhibiting short QT syndrome-type ECG in the healthy members of Japan Ground Self Defense Forces.
Methods: Our study population consisted of 4054 subjects (3943 men and 111 women, mean age of 44±6 years old) who underwent 12-lead ECG and medical evaluation during the annual health examination conducted between 1999 and 2000 in the northeast part of Japan. All subjects were followed-up thereafter till October 2004. We defined an ECG as possible short QT syndrome-type ECG when QT intervals < 320 ms at any given heart rate and as definite short QT syndrome-type ECG if QT intervals < 320 ms at heart rate around 60 beats/min.
Results: Out of 4054 subjects, 10 subjects (0.25%) showed possible short QT-type ECGs and 3 subjects had definite short QT-type ECGs. All are men and none of them had family history of SCD. During 4.2±0.8 years follow-up, no episodes of unexpected SCD, syncope and serious arrhythmias were found.
Conclusions: The prevalence of short QT symdrome-type ECG in apparently healthy population was very low and their short term prognosis is good. These results give us a useful insight into understanding short QT syndrome.