PDF(Pubmed)
Abstract：
Electrocardiogram (ECG) reconstruction from contact photoplethysmogram (PPG) would be transformative for cardiac monitoring. We investigated the fundamental and practical feasibility of such reconstruction by first replicating pioneering work in the field, with the aim of assessing the methods and evaluation metrics used. We then expanded existing research by investigating different cycle segmentation methods and different evaluation scenarios to robustly verify both fundamental feasibility, as well as practical potential. We found that reconstruction using the discrete cosine transform (DCT) and a linear ridge regression model shows good results when PPG and ECG cycles are semantically aligned-the ECG R peak and PPG systolic peak are aligned-before training the model. Such reconstruction can be useful from a morphological perspective, but loses important physiological information (precise R peak location) due to cycle alignment. We also found better performance when personalization was used in training, while a general model in a leave-one-subject-out evaluation performed poorly, showing that a general mapping between PPG and ECG is difficult to derive. While such reconstruction is valuable, as the ECG contains more fine-grained information about the cardiac activity as well as offers a different modality (electrical signal) compared to the PPG (optical signal), our findings show that the usefulness of such reconstruction depends on the application, with a trade-off between morphological quality of QRS complexes and precise temporal placement of the R peak. Finally, we highlight future directions that may resolve existing problems and allow for reliable and robust cross-modal physiological monitoring using just PPG.
摘要：
从接触式光电容积图（PPG）重建的心电图（ECG）对于心脏监测将是革命性的。我们通过首先复制该领域的开创性工作，研究了这种重建的基本和实际可行性，目的是评估所使用的方法和评估指标。然后，我们通过调查不同的周期分割方法和不同的评估方案来扩展现有的研究，以有力地验证两者的基本可行性，以及实际潜力。我们发现，在训练模型之前，当PPG和ECG周期在语义上对齐时，使用离散余弦变换（DCT）和线性岭回归模型的重建显示出良好的结果-ECGR峰和PPG收缩峰对齐。从形态学的角度来看，这种重建可能是有用的，但是由于周期对齐而丢失了重要的生理信息（精确的R峰位置）。我们还发现，在培训中使用个性化时，性能会更好，虽然在保留一个主题评估中的一般模型表现不佳，这表明PPG和ECG之间的一般映射很难得出。虽然这种重建很有价值，由于ECG包含有关心脏活动的更细粒度信息，并且与PPG（光学信号）相比提供了不同的模态（电信号），我们的研究结果表明，这种重建的有用性取决于应用，在QRS复合物的形态质量和R峰的精确时间位置之间进行权衡。最后,我们强调了可能解决现有问题的未来方向，并允许仅使用PPG进行可靠和稳健的跨模式生理监测。
