Micro-computerized system to investigate the neurocardiogenic syncope

Abstract

Syncope is defined as a sudden, transient loss of consciousness and of postural tone. Its underlying mechanism is a transient global cerebral hypoperfusion. The autonomic nervous system (ANS) of healthy individuals keeps the cerebral blood flow within a suitable range by modulating the heart rate through its sympathetic and parasympathetic branches. The sympathovagal balance can be analyzed by means of the spectral analysis of heart rate variability (HRV). There are also other factors that affect the HRV, such as the respiratory frequency. To diagnose the syncope, the Head-Up Tilt Table Test (HUTT) is carried out to induce the syncope symptoms. During the HUTT, ECG and arterial blood pressure of the patient are monitored using different commercial equipments. Nevertheless, treatment strategies are still based on an incomplete understanding of the physiological mechanisms. This work reports a dedicated system designed to sample physiological data (ECG, photopletysmography signal and respiratory waveform) during the HUTT. The developed system has an acquisition module to sample the data that are sent to a microcomputer. The patient data are shown on the microcomputer screen and stored into the hard disk. The data are simultaneously sampled to allow the investigation of the physiological mechanisms that bring the syncope about. The hardware and software of the low cost developed system are described. Signals sampled from a volunteer are shown. © 2009 Springer-Verlag.