Masked Generative Distillation for Robust Multi-Lead-to-Single-Lead ECG Classification on IoMT Devices

Wearable Internet of Medical Things (IoMT) devices typically rely on single-lead electrocardiogram (ECG) acquisition, which supports ambulatory monitoring but provides less spatial information than 12-lead clinical ECG and is more susceptible to signal corruption. Deploying accurate deep learning models on wearable hardware is also constrained by limited memory, computation and energy. This study investigates whether diagnostic knowledge from a multi-lead ECG model can be transferred to a lightweight single-lead model while improving robustness under wearable-relevant noise. A teacher-student framework is proposed in which a 12-lead 1D ResNet-18 teacher transfers knowledge to a compact single-lead convolutional neural network using masked generative distillation (MGD). The framework is evaluated on PTB-XL through a controlled ablation study covering supervised learning, conventional knowledge distillation, MGD and noise augmentation. All student variants achieve comparable macro F1 performance on clean data, indicating that the main benefit lies in robustness rather than clean-condition classification. Combining MGD with noise augmentation provides the strongest robustness under synthetic noise. Simulation-based profiling demonstrates a 45-fold parameter reduction, lower inference latency and minimal performance change after INT8 quantization. On the PTB-XL five-superclass task, the model achieves a macro F1-score of 0.6449 versus 0.626 for MVKT-ECG, although differences in lead selection and evaluation protocols prevent strict comparison.