Sensitivity Analysis of 1D Convolutional Neural Network (CNN) Model for Noise and Artifact Effects in ECG-Based Arrhythmia Detection

ECG 1D CNN arrhythmia classification class imbalance sensitivity noise robustness

Authors

9 October 2026
10 November 2026

This study evaluates a one-dimensional convolutional neural network (1D CNN) for five-class ECG heartbeat classification using a MIT-BIH-derived dataset and examines the limitations of the available evidence for noise robustness. The reported model combines convolution, flattening, batch normalization, dense layers, dropout, and a softmax output. Reanalysis of the original confusion matrix for 21,892 test beats gives 96.97% accuracy, macro sensitivity of 0.9028, macro specificity of 0.9856, macro-F1 of 0.8676, and weighted F1 of 0.9709. Supraventricular and fusion beats show lower F1-scores of 0.7094 and 0.7324, respectively. Normal beats represent 82.76% of the test set and account for most false-positive supraventricular and fusion predictions. These results demonstrate the importance of classwise metrics under substantial imbalance. Controlled noise-injection and SNR-sweep results are not yet available; therefore, the current classification results do not establish robustness to noise or artifacts. A clearly identified prospective protocol specifies artifact types, multiple SNR levels, and matched-model comparisons needed to complete that objective. The architecture is treated as a conventional baseline, and patient-independent generalization and clinical readiness remain unverified.