Ischemia and Arrhythmia Classification Using Time-Frequency Domain Features of QRS Complex

Abstract

The QRS complex is the significant wave of electrocardiogram (ECG) and occurs during ventricular depolarization. If the synchronization problem (i.e., depolarization) occurs between endocardial cardiomyocytes and outer layers, then abnormal morphological changes in QRS complex take place which is possible in case of arrhythmia and ischemia. The proposed approach describes time domain measures of such alterations (i.e., the ratio of average rise & fall amplitude and interval) of QRS complex along with the frequency domain feature i.e., peak frequency and power of mean QRS complexes. An improvised Difference Operation Method (DOM) (Yeh Yun-Chi et al., 2008) is implemented with added features like preprocessing techniques (e.g., baseline drifts and noise cancellation). The proposed methodology is evaluated with the standard databases, i.e., FANTASIA (healthy subjects), MIT-BIH Arrhythmia database (MITDB), and European ST-T database (EDB) respectively. Linear Discriminant Analysis (LDA) and decision tree are carried out for classification healthy, arrhythmic and ischemic subjects incorporating the time-frequency domain characteristics. The Naive Bayes’ Classifiers also implemented where these two classes, i.e., ischemia and arrhythmia are visually distinguished by convergently spreading in different areas. Real-time hardware validation of this approach has also executed. The future scope of this approach is to be validated with ischemia-induced arrhythmia subjects for precise identification and classification.