Photoplethysmography Indices and Their Link to Premature Ventricular Complexes on ECG

Background: The search for non-invasive and accessible markers of cardiovascular function has driven the exploration of innovative technologies, with photoplethysmography (PPG) emerging as a promising tool. Traditionally used for detecting pulse and oxygen saturation, PPG waveforms also contain valuable information about blood circulation. This single-subject, retrospective signal analysis aimed to investigate the correlation between a set of novel PPG-derived Blood Flow Indices (BFIs) and the occurrence of Premature Ventricular Complexes (PVCs). Methods: PPG waveforms and corresponding electrocardiograms (ECG) were extracted from a randomly selected individual from the Medical Information Mart for Intensive Care III (MIMIC-III) database. BFIs, including Arterial Blood Ratio (ABR), Arterial Blood Proportion (ABP), Exact Pulsatile Ratio (EPR), Waveform Ratio (WFR), and Average Peak Slope (APS), were calculated from waveforms. Statistical analyses, including Mann-Whitney U tests and the Hodges-Lehmann estimate, assessed differences and correlations between BFIs and PVC occurrence. Results: The analysis revealed statistically significant differences in the medians of BFIs between the with-PVC and without-PVC groups (p < 0.05). Mann-Whitney U tests confirmed a higher APS and lower ABR, WFR, EPR, and ABP in the with-PVC group (p < 0.0001). Harrell's C-index values (0.77–0.87) indicated a strong discriminatory ability of BFIs to detect PVCs. Conclusion: These findings suggest that BFIs derived from PPG can reliably differentiate between PVC and non-PVC events, supporting their potential as non-invasive markers.