Pulsed Electromagnetic Field Driven Perturbation of Peripheral Arterial Hemodynamics: Integrated Evidence from Doppler Ultrasound and Photoplethysmographic Signal Analysis

Pulsed electromagnetic fields (PEMF) have been widely studied for vascular and microcirculatory modulation, yet their effects on pulsatile hemodynamic organization remain poorly characterized. It is also unclear whether reversing field direction under otherwise comparable exposure conditions can alter vascular waveform behaviour. This study investigated acute direction-dependent responses to PEMF using Doppler ultrasound and photoplethysmography (PPG). Twenty healthy volunteers underwent PEMF exposure (10 Hz, 100 µs pulse width, 15 V) over the brachial artery with the coil in two opposing orientations, such that the local induced electric-field component along the arterial axis was directed either with (Forward) or against (Reverse) physiological blood flow. Downstream responses were assessed using radial artery Doppler and index-finger PPG. Participant-level feature summaries were analyzed using paired Wilcoxon signed-rank tests with Benjamini-Hochberg false-discovery-rate correction, including direct comparison of baseline-corrected Forward and Reverse responses, complemented by descriptive kernel-density L1 (KDE-L1) analysis. PPG showed the clearest participant-level responses. Six Forward features involving temporal, morphological, and pulse-area characteristics remained FDR-significant (q =0.018-0.037), whereas five Reverse features involving systolic amplitude, notch timing, and spectral organization remained significant (q = 0.003-0.012). Direct Forward-Reverse comparison identified significant differences in eight PPG features spanning amplitude, area, temporal, and spectral domains (q =0.005-0.029). Doppler showed a more selective response, with Forward Cardiac Cycle Duration remaining FDR-significant (q= 0.014), together with broader KDE-L1 redistribution of arterial velocity-waveform characteristics. These findings demonstrate orientation-sensitive peripheral pulse-wave responses together with complementary arterial waveform changes, supporting field direction as a potentially relevant exposure parameter in vascular PEMF research.