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This study focuses on the development of a passive, lightweight skin patch sensor that can measure fluid volume changes in the heart in a non-invasive, point-of-care setting. The wearable sensor is an electromagnetic, self-resonant sensor configured into a specific pattern to formulate its three passive elements (resistance, capacitance, and inductance). In an animal model, a bladder was inserted into the left ventricle (LV) of a Bovine heart and fluid was injected using a syringe to simulate stoke volume (SV). In a human study, to assess the dynamic fluid volume changes of the heart in real time, the sensor frequency response was obtained from a participant in a 30° head-up tilt (HUT), 10° HUT, supine and 10° head-down tilt (HDT) positions over time. In the animal model, an 80 mL fluid volume change in the LV resulted in a downward frequency shift of 80.16 kHz. In the human study, there was a patterned frequency shift over time which correlated with ventricular volume changes in the heart during the cardiac cycle. Statistical analysis showed a linear correlation R2 = 0.98 and 0.87 between the frequency shifts and fluid volume changes in the left ventricle of the bovine heart and human participant, respectively. Additionally, the patch senor detected heart rate (HR) in a continuous manner with a 0.179 % relative error compared to electrocardiography (ECG). These results provide promising data regarding the ability of the patch sensor to be a potential technology for SV monitoring in a non-invasive, continuous, non-clinical setting.READ FULL ARTICLE ON IEEE XPLORE