European Heart Journal Advance Access originally published online on October 2, 2008
European Heart Journal 2009 30(2):202-208; doi:10.1093/eurheartj/ehn452
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Changes of the corrected QT interval in healthy boys and girls over day and night
1 Department of Pediatric Cardiology, University Children's Hospital Muenster, Albert-Schweitzer-Str. 33, D-48149 Muenster, Germany
2 Department of Pediatric Cardiology, Evelina Children's Hospital, Guy's & St Thomas NHS Foundation Trust, Lambeth-Palace Road, London SE1 7EH, UK
3 Klinikum Minden, Kinderklinik, Portastraße 7-9, 32427 Minden, Germany
4 Institute of Biomedical Statistics, Westfalian Wilhelms-University Muenster, Albert-Schweitzer-Str. 33, D-48149 Muenster, Germany
Received 24 March 2007; revised 24 June 2008; accepted 18 September 2008; online publish-ahead-of-print 2 October 2008.
* Corresponding author. Tel: +44 20 71884562, Fax: +44 20 71884556, Email: thomas.krasemann{at}gstt.nhs.uk
Aims: The study was designed to detect changes in corrected QT intervals over day and night in both sexes in healthy children.
Methods and results: The corrected QT interval was calculated from 24 h ECGs obtained from 282 healthy children aged 6 months to 18 years. The QTc interval as measured by the 24 h recording differs to the standard ECG measurement which is in average of 40–50 ms shorter. The QTc interval changes little over a 24 h period and is remarkably constant despite significant heart rate changes in healthy children.
Conclusion: The routine ECG—even if the calculated values differ markedly from those obtained over 24 h—seems to be a good screening method for the measurement of corrected QT intervals, because the corrected QT interval is kept constant over the whole day in healthy children.
Key Words: QT-interval 24-hour-ECG Children