A Portable Diagnostic Device for Cardiac Magnetic Field Mapping

In this paper we present a portable magnetocardiography device. The focus of this development was delivering a rapid assessment of chest pain in an emergency department. The aim was therefore to produce an inexpensive device that could be rapidly deployed in a noisy unshielded ward environment. We found that induction coil magnetometers with a coil design optimized for magnetic field mapping possess sufficient sensitivity ($104fT/\sqrt{Hz}$ noise floor at 10Hz) and response ($813fT/\mu V$ at 10Hz) for cycle averaged magnetocardiography and are able to measure depolarisation signals in an unshielded environment. We were unable to observe repolarisation signals to a reasonable fidelity. We present the design of the induction coil sensor array and signal processing routine along with data demonstrating performance in a hospital environment.