Ventricular Inhomogeneity and Beat-to-beat QT Interval
Variability after Surgical Repair of Tetralogy of Fallot |
Su-Hyun Kim1, Myung-Kul Yum1, Nam-Su Kim1, Chang-Ryul Kim1, Chul-Burm Lee2, Chung-Ill Noh3, Hee-Soo Kim4 |
1Department of Pediatrics, Hanyang University Kuri Hospital, Korea 2Department of Thoracic Surgery, Hanyang University Kuri Hospital, 3Department of Pediatrics, Seoul University Hospital, Korea 4Department of Anesthesiology, Seoul University Hospital, Korea |
활로 4징 교정수술 환아에서 심실재분극의 불균일성과 QT간격변이 분석 |
김수현1, 염명걸1, 김남수1, 김창렬1, 이철범2, 노정일3, 김희수4 |
1한양대학교 의과대학 소아과학교실 2한양대학교 의과대학 흉부외과학교실 3서울대학교 의과대학 소아과학교실 4서울대학교 의과대학 마취과학교실 |
Correspondence:
Myung-Kul Yum, Email: mkyumm@email.hanyang.ac.kr |
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Abstract |
Purpose : The object of this study is to determine whether QT interval variability in patients with postoperative tetralogy of Fallot increases.
Methods : We enrolled 41 patients who had total correction of tetralogy of Fallot, and 31 healthy controls. They were 6-12 years old. Patients were divided into 2 groups : arrhythmia-positive patients(n=10) who had ventricular premature contractions more than 30/hour or who had couplets, and arrhythmia-negative patients(n=31). We selected the 10-minute arrhythmia-free portion of 24-hour ambulatory ECG recorded during sleep(1-3AM). We selected the 2nd beat of recordings for a template, then found the QT interval for each beat. The method was that T-wave shape best matches template T-wave under the time-stretch model. The mean heart rate and variance and mean QT interval and variance were computed and then a QT variability index(QTVI)-which represents the log ratio between QT interval variability and heart rate variability-was derived.
Results : Postoperative tetralogy of Fallot patients with/without ventricular arrhythmia showed significantly increased QTVI compared with the control(-0.481¡¾0.310/-0.661¡¾0.376 vs -1.200¡¾0.380, P<0.0001). There was a trend that QTVI in patients with ventricular arrhythmia increased more than in patients without ventricular arrhythmia, but there were no statistical significances.
Conclusion : QT interval variability increased in repaired tetralogy of Fallot patients with/without ventricular arrhythmia compared with the control. And this finding indicates that inhomogeneity of temporal ventricular repolarization exists in repaired tetralogy of Fallot patients. |
Key Words:
Tetralogy of fallot, Ventricular arrhythmia, Temporal ventricular repolarization inhomogeneity, QT variability index |
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