2021 Volume 37 Issue 1 Pages 29-34
Background: The heart-rate–corrected QT interval (QTc) by automatic measurements is longer than that by manual measurements. The reference QTc values used for screening QT prolongation in school cardiac screening are generated by manual measurements; when such values are used in automatic measurements, overscreening occurs.
Methods: We retrospectively analyzed the electrocardiogram records of all first- and seventh-grade students who underwent school cardiac examinations in Kagoshima City from 2009 to 2013. Only students screened using the automated QTc values underwent manual measurements, and those who exceeded the manual reference QTc values were selected. The automated reference values were developed according to the automatically measured QTc values of the extracted students.
Results: Out of 54,586 students, 1233 (2.3％) were screened using manual measurement. Among them, 52 (0.10％) exceeded the reference QTc values. The lowest automated QTc values were 445 and 447 ms for first-, 463 and 451 ms for seventh-grade male and female students, respectively.
Conclusion: The reference values for the automatic screening of QT prolongation were 445 and 450 ms in first- and seventh-grade students, respectively.
