Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Diurnal Changes of Heart Rate and Sympathovagal Activity for Temporal Patterns of Transient Ischemic Episodes in 24-Hour Electrocardiograms | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 32386 10 pages doi 2007 32386 Research Article Diurnal Changes of Heart Rate and Sympathovagal Activity for Temporal Patterns of Transient Ischemic Episodes in 24-Hour Electrocardiograms A. Smrdel and F. Jager Faculty of Computer and Information Science University of Ljubljana 1000 Ljubljana Slovenia Received 26 April 2006 Revised 27 October 2006 Accepted 11 January 2007 Recommended by Maurice Cohen We test the hypothesis that different temporal patterns of transient ST segment changes compatible with ischemia ischemic episodes are a result of different physiologic mechanisms responsible for ischemia. We tested the hypothesis using records of the Long-Term ST Database. Each record was divided into three intervals of records morning day and night intervals and was inserted into one of three sets according to the temporal pattern of ischemia salvo periodic and sporadic pattern. We derived time-and frequency-domain parameters of the heart rate time series in selected intervals in the neighborhood of ischemic episodes. We used the adaptive autoregressive method with a recursive least-square algorithm for consistent spectral tracking of heart rate time series and to study frequency-domain sympathovagal behavior during ischemia. The results support the hypothesis that there are at least two distinct populations which differ according to mechanisms and temporal patterns of ischemia. Copyright 2007 A. Smrdel and F. Jager. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Ischemia is one of the most common heart diseases. It is caused by the insufficient supply of the heart muscle with the oxygen which can cause part of the heart muscle to become electrically inactive and can in turn lead to
