Department of Biomedical Engineering, Hashemite University, Zarqa, Jordan.
Med Biol Eng Comput. 2010 Feb;48(2):177-84. doi: 10.1007/s11517-009-0548-7. Epub 2009 Nov 19.
Paradoxical splitting occurs when pulmonic valve (P2) closes before the aortic valve (A2). This causes second heart sound (S2) to be a single sound during inspiration and split during exhalation. Etiology delay in aortic closure: aortic stenosis, volume overload of left ventricle (LV), conduction defects in LV, and left bundle branch block (LBBB). In this article, a method was proposed in early detection of a reverse in the appearance of A2 and P2 within S2. This method is based on the time-frequency maps obtained with the continuous wavelet transform (CWT), namely, the Meyer wavelet. A number of patients with LBBB and others with fitted pacemakers were studied. The above method is combined with the support vector machine (SVM) and performance of this method is evaluated using classification accuracy (Ca), sensitivity (Se), specificity, positive, and negative predicted values. Results show that it is relatively easy to detect the reverse in A2 and P2 and the Ca and Se is 90.97 and 94.44%, respectively, for the sample of 42 patients whose data were collected from the Cardiology Department at Brighton and Sussex University Hospital in England.
反常分裂是指肺动脉瓣（P2）在主动脉瓣（A2）关闭之前关闭。这导致第二心音（S2）在吸气时为单一声音，并在呼气时分裂。主动脉瓣关闭延迟的病因：主动脉瓣狭窄、左心室（LV）容量超负荷、LV 传导障碍和左束支传导阻滞（LBBB）。本文提出了一种在 S2 内早期检测 A2 和 P2 反转的方法。该方法基于连续小波变换（CWT）获得的时频图，即 Meyer 小波。研究了一些患有 LBBB 的患者和其他装有起搏器的患者。该方法与支持向量机（SVM）相结合，并使用分类准确性（Ca）、敏感性（Se）、特异性、阳性和阴性预测值来评估该方法的性能。结果表明，检测 A2 和 P2 的反转相对容易，对于从英国布莱顿和苏塞克斯大学医院心脏病科收集的数据为 42 名患者的样本，Ca 和 Se 分别为 90.97%和 94.44%。
