Abnormal Fractal Correlation of Heart Rate in
Children with Neurocardiogenic Syncope |
Keoung-Young Kim1, Eun-Young Joo1, Myung-Kul Yum1, Je-Wen Oh1, Chang-Ryul Kim1, Nam-Su Kim1, Cheol-Beom Lee2, Chung-Ill Noh3 |
1Department of Pediatrics, College of Medicine, Hanyang University, Kuri, Korea 2Department of Thoracic & Cardiovascular Surgery, College of Medicine, Hanyang University, Kuri, Korea 3Department of Pediatrics, College of Medicine, Seoul University, Seoul, Korea |
소아 신경심장성 실신환자에서비정상적 심박수 프랙탈 상관에 대한 연구 |
김경용1, 주은영1, 염명걸1, 오재원1, 김창렬1, 김남수1, 이철범2, 노정일3 |
1한양대학교 의과대학 소아과학교실 2한양대학교 의과대학 흉부외과학교실 3서울대학교 의과대학 소아과학교실 |
Correspondence:
Myung-Kul Yum, Email: mkyumm@hanyang.ac.kr |
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Abstract |
Purpose : The purposes of this study were to determine short- and long-term fractal correlation behavior of heart rates during daily activity in patients with neurocardiogenic syncope.
Methods : Twenty five patients with histories of neurocardiogenic syncope episodes were included. Their analogue 24h ambulatory Holter electrocardiograms were analyzed. The tape was digitized and the digitized electrocardiograms were partioned into sections of one hour. Then their RR intervals were measured and 20,000 points of RRI were used. To quantify the fractal correlation behavior, we employed the detrended fluctuation analysis, and short-term(n≤16, α1) and long-term(n>16, α2) fractal scaling exponents were calculated.
Results : When compared to control, 24-hour average values of α1 and all α1 values at quarters of each day were significantly higher in patients with syncope. On the contrary, their 24-hour average value of α2 and all α2 values at quarters of each day were lower in patients with syncope. However, statistical significances were found in 24-hour average value of α2 and in α2 value at MN-6AM.
Conclusion : In the syncope patients with neurocardiogenic syncope, short-term fractal scaling exponents of RR interval was significantly high throughout the day. Therefore, their RR intervals were smoother in the short term scale and had a tendency to continue in the same direction of increase or decrease, which may contribute to persistent decrease in heart rate during a syncopal attack. |
Key Words:
Neurocardiogenic syncope, RR interval variability, Fractal scaling exponent, Detrended fluctuation analysis |
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