Using non-linear dynamics methods, we have comparatively analyzed the HRV (heart rate variability ) of the healthy people and the HRV of those with arrhythmia. The Lyapunov exponent of the healthy group's HRV is different from that of the arrhythmia group's HRV. The largest Lyapunov exponent of the healthy people's HRV is 0.45907. But in the abnormal situation, the value of a reduces, and the largest Lyapunov exponent of the arrhythmia group's HRV is 0. 41472. They are both chaotic system, however the level of the chaos of those with arrhythmia is apparently lower than that of the healthy people.
Algorithms ; Arrhythmias, Cardiac ; physiopathology ; Data Interpretation, Statistical ; Electrocardiography ; methods ; Heart Rate ; physiology ; Humans ; Nonlinear Dynamics ; Signal Processing, Computer-Assisted

In this paper, a prediction and real-time monitoring method for changing in ECG signals is proposed based on Kalman filter technique. It is important that the change point such as jump and drift could be predicted and diagnosed from the measurement, so as to keep it safely. The Kalman filter technique can be used in estimating system states in real-time way. The sudden changes of the estimation errors of system status can be used as the predictor for the physiologic changes. This method is validated in practice according to the experimental results.
Arrhythmias, Cardiac ; physiopathology ; Electrocardiography ; methods ; Heart Rate ; physiology ; Humans ; Monitoring, Physiologic ; methods ; Signal Processing, Computer-Assisted ; Software

Objective To evaluate the long-term efficacy of cervical artificial disc replacement for patients with degenerative cervical canal stenosis.Methods All of 43 patienta underwent single level Bryan cervical artificial disc replacement for degenerative cervical canal stenosis were retrospectively analyzed with a minimum 10 years follow-up in our hospital between December 2003 and December 2007.There were 28 males and 15 females with an average age of 56.7 ± 8.0 years which ranged from 37 to 76 including 1 case of C3.4 level,11 xases of ~ level,26 cases of C~ level and 5 cases of C6,7 level.According to the symptoms and location of compression on radiograph,the patients were divided into 3 groups:15 patients in radiculopathy group,10 patients in myelopathy group and 18 patients in myeloradiculo p~hy group.Radidogical evaluation indexes include global range of motion (ROM),segmental ROM,segmental Cobb angle.Clinical evaluation indexes including Japanese Orthopaedic Association (JOA) score,neck disability index (NDI) and Odom's criteria.The variable data were analyzed by one-way ANOVA,the grading data were analyzed by Kruskal-Wallis H test.The preoperative and postoperative data were analyzed by paired t test.Results At the last follow-up,the Cobb angle of the operative segment was 1.29°±1.34°in myelopathy group(t=4.606,P=0.001),0.71°±2.20°in radiculopathy group (t=2.355,P=0.034),and 0.69°±2.12° in myeloradiculopathy group (t=3.312,P=0.004),which was significantly lower than that before operation.At the last follow-up,ROM of the operative segment in myelopathy group was 6.41 o ±4.87°,which was significantly lower than that before operation (11.46° ±5.19°,t=3.589,P＜ 0.05),and there was no significant difference in the other two groups.There was no significant difference in other imaging parameters among the three groups.JOA scores at the last follow-up were 16.33±0.75 in radiculopathy group (t=5.857,P＜ 0.001),16.00±1.05 in myelopathy group(t=8.337,P＜ 0.001) and 14.78±1.69 in radiculopathy group (t=4.045,P＜ 0.001);NDI were 13.07％±5.90％ in radiculopathy group (t=7.097,P＜ 0.001),12.60％±4.22％ in myelopathy group (t=7.319,P＜ 0.001) and 23.11％±14.18％ in radiculopathy group (t=4.229,P＜ 0.001),which were all significantly improved than those before operation.The excellent and good rate of Odom's criteria (H=2.719,2.411,P＜ 0.05),JOA (LAD-t=3.770,4.080,P＜0,05) and NDI(LAD-t=2.850,2.643,P＜ 0.05) at the last follow-up of the patients in radiculopathy group and myelopathy group were better than those of patients in myeloradiculopathy group (P＜ 0.05).Conclusion Cervical artificial disc replacement has a satisfied long-term clinical efficacy with degenerative cervical canal stenosis.The efficacy of myelopathy and radiculopathy were better than myeloradiculopathy.