健康成人男女におけるＱＴ／ＱＴｃ間隔についての検討―性差，年齢によるＱＴ／ＱＴｃ間隔への影響および測定法による差異についての検討―

Abstract

Aims : The aim of this study was to investigate the effects of sex and age on QT/QTc interval in healthy Japanese males and females. In addition, we investigated the difference in the evaluations between manual read and automatic read standard 12-lead electrocardiography (ECG).Methods : In the present study 309 subjects (175 males, 134 females, age : 20-78 years), who had undergone clinical laboratory tests including ECG, physical examination and biochemical blood test in Kan-nondai clinic were enrolled. ECG measurement was made by a Mortara ELI 250 ECG, and the ECG was performed three times every minute for each subject. Electronic ECG data (chart paper) was sent to the outside evaluating system of eResearch Technology Inc. for the manual read. QT/QTc interval data were corrected as QTcB (Bazett's correction) and QTcF (Fridericia correction) and were evaluated according to factors including gender and age. In addition, QT/QTc intervals were compared between manual read and automatic read ECG.Results : The QTcB and QTcF were significantly longer in females (425±18 msec, 421±15 msec, respectively) than males (407±24 msec, 405±20 msec, respectively) in the present enrolled subjects (p<0.0001 in both QTcB and QTcF). The corrected QT/QTc tended to be correlated with age, and slightly positive, in both male and female subjects, although the correlation was marginally significant for QTcB in males. From actual observation ECG parameters calculated from the manual read were shorter than those from the automatic read (% of manual<automatic read : 87.5% for QT, 80.5% for QTcB and 84.7% for QTcF). The measurement deviation of the parameters was 15±10 msec for QTcB and 12±10 msec for QTcF.Conclusions : These results suggested that a ECG parameters study covering a wide range of males and females should be required for developmental drugs with the potential to induce QT/QTc prolongation.