Characterization of surrogate parameters for blood pressure regulation in neurally-mediated syncope

Neurally Mediated Syncope (NMS) is often cited as the most common cause of syncope. It can lead to severe consequences such as injuries, high rates of hospitalization and reduced quality of life, especially in elderly populations. Therefore, information about the syncope triggers and reflex mechanisms would be of a great value in the development of a cost-effective p-health system for the prediction of syncope episodes, by enhancing patients' quality of life and reducing the incidence of syncope related disorders/conditions. In the present paper we study the characterization of syncope reflex mechanisms and blood pressure changes from the analysis of several non-invasive modalities (ECG, ICG and PPG). Several parameters were extracted in order to characterize the chronotropic, inotropic and vascular tone changes. Thus, we evaluate the ability of parameters such as Heart Rate (HR), Pre-Ejection Period (PEP) and Left Ventricular Ejection Time (LVET) to characterize the physiological mechanisms behind the development of reflex syncope and their potential syncope prediction capability. The significant parameter changes (e.g. HR from 12.9% to -12.4%, PEP from 14.9% to -3.8% and LVET from -14.4% to 12.3%) found in the present work suggest the feasibility of these surrogates to characterize the blood pressure regulation mechanisms during impending syncope.