Non contact ECG recording instrument for continuous cardiovascular monitoring

The proposed non-contact ECG scheme presented in this article is based on sensing the variations in the electric potential close to the patient´s relevant body surface. In order to measure the potential, suitable capacitive electrodes are designed and developed. The signal coupled from the active electrodes are amplified, filtered, digitized using NI myDAQ and displayed in a Virtual Instrument developed in a LabVIEW environment. A prototype has been built, tested and non-contact ECG signals have been obtained from the body of many volunteers and verified with their conventional ECG. It has been noticed that the developed noncontact scheme provides reliable and very good signal quality without losing any important morphological information compared to a conventional ECG. In order to improve the signal quality, an operational amplifier with very good CMRR, active shielding provision for electrodes and a right leg driver circuit for reference electrode are used.