Automatic ECG Classification Using Continuous Wavelet Transform and Convolutional Neural Network

Early detection of arrhythmia and effective treatment can prevent deaths caused by cardiovascular disease (CVD). In clinical practice, the diagnosis is made by checking the electrocardiogram (ECG) beat-by-beat, but this is usually time-consuming and laborious. In the paper, we propose an automatic ECG classification method based on Continuous Wavelet Transform (CWT) and Convolutional Neural Network (CNN). CWT is used to decompose ECG signals to obtain different time-frequency components, and CNN is used to extract features from the 2D-scalogram composed of the above time-frequency components. Considering the surrounding R peak interval (also called RR interval) is also useful for the diagnosis of arrhythmia, four RR interval features are extracted and combined with the CNN features to input into a fully connected layer for ECG classification. By testing in the MIT-BIH arrhythmia database, our method achieves an overall performance of 70.75%, 67.47%, 68.76%, and 98.74% for positive predictive value, sensitivity, F1-score, and accuracy, respectively. Compared with existing methods, the overall F1-score of our method is increased by 4.75~16.85%. Because our method is simple and highly accurate, it can potentially be used as a clinical auxiliary diagnostic tool.     

慢性肺心病急性发作期患者低钾血症与心律失常关系探讨

对165例慢性肺心病急性发作期患者和40例健康人的血清钾水平进行了分析,并比较了165例慢性肺心病急性发作期患者在不同血清钾水平下心律失常发生率。结果显示,慢性肺心病急性发作期患者血清钾水平低于健康人,P＜0．01,具有显著差异;而在慢性肺心病急性发作期患者中,低钾血症者心律失常发生率高于清钾正常者,P＜0．05,有显著差异。说明慢性肺心病急性发作期患者低钾血症多见,而血清钾降低增加慢性肺心病患者心律失常的发生。     

Pharmacokinetics of aconitine in rat skin after oral and transdermal gel administrations

The purpose of this study was to evaluate percutaneous penetration and arrhythmogenic effects of aconitine after transdermal administration, compared with the oral route. Skin penetration of aconitine was tested by a microdialysis technique in rats and in vivo recovery was determined by retrodialysis. After oral and transdermal administration of aconitine, dialysate was sampled at 20 min intervals until the end of the experiment for the determination of concentration of aconitine in skin. Blood samples were collected and analyzed using a validated HPLC‐MS/MS method. In addition, we concurrently recorded the electrocardiogram (ECG). The in vivo recovery of aconitine in the skin was calculated to be 39.59%. The C_max values for aconitine absorbed into the skin after oral and transdermal administration were 1.51 ± 0.53 and 2723.8 ± 848.8 ng/mL, respectively, and within the plasma, 215.86 ± 79.29 and 20.92 ± 3.15 ng/mL. The C_max value for the plasma concentration of aconitine after oral administration was approximately 10 times higher than with the transdermal route. For oral administration, the ECG revealed various types of arrhythmias at a period of T_max, which is normal in transdermal gel administration. These results indicate that transdermal aconitine gel is a safe formulation that can deliver the drug in sufficient amounts and safe concentrations to produce therapeutic action in rats. Copyright © 2011 John Wiley & Sons, Ltd.     

用运动控制器来终止心律失常

采用Luo-Rudy相Ⅰ心脏模型对通过局部电击使细胞复极化来消除心脏中的螺旋波和时空混沌进行数值模拟.提出利用控制器局部电击螺旋波波头周围的心肌细胞来抑制螺旋波的旋转,使螺旋波漂移出边界,进而控制螺旋波和时空混沌.数值模拟表明:适当选择控制的格点数和膜电位控制阈值,螺旋波和时空混沌都可以被抑制.最少的控制格点数为9个,...     

施太可治疗心律失常的剂量探讨

目的：探索国人应用施太可（索他洛尔）治疗心律失常的疗效和合适剂量。方法：对５３例非心肌梗塞的心律失常患者采用施太可治疗,分别不同剂量（４０～２４０ｍｇ／ｄ）,观察疗效及不良反应,用临床及动态心电图进行评定。结果：（１）栓部５３例患者应用施太可治疗后,总有效３９例,总有效率达７３．５８％。（２）３９例有效病例平均剂量为９３．５７ｍｇ／ｄ。（３）应用小剂量施太可后ＱＴｃ延长及心率减慢均有显著差异,但对