Wireless sensor node for non-invasive high precision electrocardiographic signal acquisition based on a multi-ring electrode

•We present a portable high-precision wireless sensor node for three ECG signals.•We present a new flexible multi-ring electrode for acquiring ECG signal.•We check the influence of the dimension of concentric ring electrodes.•The electrodes dimensions affect the signal amplitude and morphology. Concentric ring electrodes (CRE) have been proposed for sensing bioelectrical activity with high spatial resolution. Computational studies have revealed that the CRE dimensions are closely related to the electric dipole depth they can sense, but further experimental confirmation is needed. We aimed to develop and test a wireless multichannel ECG recording system based on a new flexible multi-ring electrode and to check the influence of CRE dimensions on the acquired signals. The system provided high-precision ECG signals by a simple procedure. The bipolar concentric ECG signal amplitude and SNR increase with the CRE’s outer ring dimension. Differences in the signal morphologies, associated with different sensitivities to the location of the active dipoles, were also obtained in the case of diameters smaller than 34mm. A system with several wireless sensor nodes developed could be easily used by clinical staff for non-invasive cardiac monitoring and diagnosis with high spatial and temporal resolution.