Background:The epidemiology of short QT interval remains unclear. We attempted to determine the incidence and clinical characteristics of short QT interval in a longitudinal cohort study.
Methods:A total of 19,153 subjects (7,525 male, 11,628 female) were enrolled in the study and all available electrocardiograms (ECGs) were investigated longitudinally from 1958 through 2003. We defined short QT interval as QTc of less than 350 ms.
Results:Of the 19,153 subjects, two met the criteria of short QT interval and allowed for prevalence and incidence estimates for short QT interval as 0.01% and 0.39/100,000 person-years, respectively. Both cases had neither a family history of sudden cardiac death, nor a history of drug use that might have affected for QT interval. Case 1 was a female with history of ischemic heart disease. Case 2 was a 60-year-old male who exhibited a short QT interval for the first time when he was 26 years of age. He had sick sinus syndrome as an underlying heart disease.
Conclusions:Of the 19,153 subjects in this study, none were identified as having the short QT syndrome, with associated high risk of ventricular tachyarrhythmia, atrial fibrillation, and sudden death. Two subjects were identified as having QTc of less than 350 ms, and allowed prevalence and incidence estimates to be made of short QT interval. There observations were suggestive of clinical relationships between short QT interval and organic or electrophysiological heart disease.