KUSUKI Hirofumi, KURIKI Marina, HORIO Kayo, HOSOI Misa, MATSUURA Hideaki, FUJINO Masayuki, MIYATA Masafumi, YAMAZAKI Toshio, NAGAOKA Shunji, YASUDA Toshiaki, HATA Tadayoshi
Japanese Journal of Electrocardiology, 29(4) 290-297, Oct, 2009
The relationship between electrocardiographic RR and QT interval variabilities were evaluated, based on the QT variability ratio (VR) in prepubescent children, to investigate the influence of aging. One hundred and seventy-six subjects with no heart disease, ranging from infants to school children, were categorized into 6 groups for a comparative study ; Group I(17 infants aged 0 to 6 months), Group II(21 infants aged 7 to 11 months), Group III(28 infants aged 1 year), Group IV(37 children aged 2 to 3 years), Group V(36 children aged 4 to 5 years), Group VI(37 children aged 6 to 7 years). Regarding the methods, the RR-interval and QT-interval of 120 heart beats were measured at rest to calculate the VR based on the standard deviation of the RR-interval (SDRR) and the standard deviation of the QT-interval (SDQT) in order to investigate the relationship with the age of subjects (months). As a result, there were no gender differences between groups for VR, SDRR and SDQT, and VR decreased in accordance with aging, but became stable when the children reached school age. This study supports the potential application of the standard value of VR by age to evaluate imbalances in the cardiac cycle and myocardial repolarization.