Novel interpretable Feature set extraction and classification for accurate atrial fibrillation detection from ECGs

Objective: We present a novel method for detecting atrial fibrillation (AFib) by analyzing Lead II electrocardiograms (ECGs) using a unique set of features. Methods: For this purpose, we used specific signal processing techniques, such as proper orthogonal decomposition, continuous wavelet transforms, discrete cosine transform, and standard cross-correlation, to extract 48 features from the ECGs. Thus, our approach aims to more effectively capture AFib signatures, such as beat-to-beat variability and fibrillatory waves, than traditional metrics. Moreover, our features were designed to be physiologically interpretable. Subsequently, we incorporated an XGBoost-based ECG classifier to train and evaluate it using the publicly available ‘Training’ dataset of the 2017 PhysioNet Challenge, which includes ‘Normal,’ ‘AFib,’ ‘Other,’ and ‘Noisy’ ECG categories. Results: Our method achieved an accuracy of 96 % and an F1-score of 0.83 for ‘AFib’ detection and 80 % accuracy and 0.85 F1-score for ‘Normal’ ECGs. Finally, we compared our method's performance with the top-classifiers from the 2017 PhysioNet Challenge, namely ENCASE, Random Forest, and Cascaded Binary. As reported by Clifford et al., 2017, these three best performing models scored 0.80, 0.83, 0.82, in terms of F1-score for ‘AFib’ detection, respectively. Conclusion: Despite using significantly fewer features than the competition's state-of-the-art ECG detection algorithms (48 vs. 150–622), our model achieved a comparable F1-score of 0.83 for successful ‘AFib’ detection. Significance: The interpretable features specifically designed for ‘AFib’ detection results in our method's adaptability in clinical settings for real-time arrhythmia detection and is even effective with short ECGs (<10 heartbeats).