Replication Data for: Sawtooth artifact in beat-to-beat pulse transit time

Photoplethysmography (PPG) is a useful tool for monitoring pulse and oxygenation. Pulse transit time (PTT) calculated as the time interval between heart beat and peripheral pulse provides additional information about the cardiovascular system. However, not all off-the-shelf PPG and electrocardiogram (ECG) monitoring devices, even integrated together, are suitable for this purpose. In this retrospective clinical study of PTT signal collected in 35 subjects. We present a problem with the PTT signal referred to as sawtooth artifact. We also propose an approach based on the de-shape method to visualize and quantify the sawtooth artifact to confirm it as an artifact. One file represents one kind of time-series data. Filenames contain "Wave500Hz_ECG_II", "Wave500Hz_Pleth", "Trend4Hz_PPG_PTT", and "Trend4Hz_RRI_DN" represent the lead II electrocardiography raw data in 500Hz sampling rate, the photo-plethysmography waveform data in 500Hz sampling rate, the derived pulse transit time data in 4Hz sampling rate, and the derived R-R peak interval in 4Hz sampling rate respectively. Data from each case contain these 4 files so that the viewer can check the sawtooth artifact directly from the "*Trend4Hz_PPG_PTT.txt" data, or calculate the PTT data from the ECG signal and the PPG signal by himself. The PDF files are the result of time-frequency analysis showing the constant frequency of the sawtooth artifact. The "*.m" files are the MATLAB routines the authors used to perform the time-frequency analysis by the "de-shape" method.