QT Variability Index is Correlated with Autonomic Nerve Activity in Healthy Children

Hirofumi Kusuki, Yuka Tsuchiya, Yuri Mizutani, Miki Nishio, Shota Oikawa, Rina Nagata, Yumi Kiriyanagi, Kayo Horio, Arisa Kojima, Hidetoshi Uchida, Namiko Kojima, Kazuyoshi Saito, Tsuneaki Sadanaga, Tadayoshi Hata

Research output: Contribution to journalArticlepeer-review


The QT variability index (QTVI), which measures the instability of myocardial repolarization, is usually calculated from a single electrocardiogram (ECG) recording and can be easily applied in children. It is well known that frequency analysis of heart rate variability (HRV) can detect autonomic balance, but it is not clear whether QTVI is correlated with autonomic tone. Therefore, we evaluated the association between QTVI and HRV to elucidate whether QTVI is correlated with autonomic nerve activity. Apparently, healthy 320 children aged 0–7 years who visited Fujita Health University Hospital for heart checkup examinations were included. The RR and QT intervals of 60 continuous heart beats were measured, and the QTVI was calculated using the formula of Berger et al. Frequency analysis of HRV, including the QTVI analysis region, was conducted for 2 min and the ratio of low-frequency (LF) components to high-frequency (HF) components (LF/HF) and HF/(LF + HF) ratio was calculated as indicators of autonomic nerve activity. Then, the correlations between QTVI and these parameters were assessed. QTVI showed a significant positive correlation with LF/HF ratio (r = 0.45, p < 0.001) and negative correlation with HF/(LF + HF) ratio (r = −0.429, p < 0.001). These correlations remained after adjustment for sex and age. QTVI, which is calculated from non-invasive ECG and can detect abnormal myocardial repolarization, is significantly correlated with frequency analysis of HRV parameters. QTVI reflects autonomic nerve balance in children.

Original languageEnglish
Pages (from-to)1432-1437
Number of pages6
JournalPediatric Cardiology
Issue number7
Publication statusPublished - 01-10-2020

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health
  • Cardiology and Cardiovascular Medicine


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