Development of a low cost mobile system for monitoring cardiac activity based on noncontact electrodes

Abstract

Here we present the design, implementation and testing of a mobile system for ambulatory monitoring of cardiac activity, it uses capacitive electrodes that do not need of direct contact with the skin. The system uses the material between the skin and the electrodes as a dielectric for the capacitor formed between them. The device pretends to monitor heart activity in people with high skin sensitivity or with injuries, it could also be used as part of the attire of professionals such as pilots. Our hypotheses were the following: 1) It is possible to develop a system that allows monitoring heart activity through a mobile device, without the need conductor gel or even in direct contact to the skin. 2) The implemented electrodes will be able to take data with and without direct contact with the skin. 3) The system will be able to get electrocardiographic signal through at least three different type of textures. All the hypotheses were satisfied. The performance of the system was evaluated by acquiring measurements, using different textures as dielectric and then performing a paired t-test comparing them with a signal of wet Ag/Cl electrodes that are considered the gold standard now, the results suggested that there is not significative difference between the signals taken with the implemented electrodes and the ones taken with the Ag/Cl electrodes. Connectivity and performance of the App were also tested by using it and obtaining satisfactory results.