Contactless detection of pacemaker pulses by measuring the associated magnetic field

摘要

A new sensor capable to detect pacemaker pulses without using electrodes is presented. The magnetic field associated to the pacing current is sensed by a coil placed in proximity of the pacemaker wire, without the need of any electric connection with the patient. The new sensor is capable to provide accurate measurement of the occurrence and timing of pacemaker pulses. Hence, it provides important information about the pacemaker functioning, which can be used in patient's monitoring and pacemaker device assessment. An in-vitro testing of the new sensor was carried out involving a real unipolar pacemaker immersed in saline solution. A wideband ECG circuit was also realized to record pacemaker pulses. The electrocardiographic signal and the output of the sensor were simultaneously recorded and compared. A microcontroller-based circuit provides accurate timing measurements of inter-pulse intervals and pulse duration and display them in real-time. Preliminary results suggest the possibility to use the new sensor to achieve prolonged, passive, unobstructive and wearable monitoring of pacemaker patients during their daily life activities. Accurate timing of the pacemaker pulse can also support standard ECG diagnosis and measurement of the residual charge of the pacemaker battery.