Evaluation of currents induced in the heart as a consequence of standing in strong static magnetic field

Abstract

In the last few years we have been watching a remarkable development of technologies using high density static magneticfields in industry and medicine. In medical environment the diagnostic use of Magnetic Resonance (MR) has becomethe Gold Standard to identify a great number of pathologies. The increase of static magnetic field intensity levels,besides the equipment resolution’s gain and the application fields widening, has led to a substantial decrease of clinicalexamination duration with economic benefits and better comforts for the patient. On the other hand we have witnessedan increase of problems connected with the exposure to high density static magnetic fields. This work focuseson the research of a model thought to evaluate currents induced within the heart, as a consequence of the exposure tothe static magnetic field produced by a Magnetic Resonance scanner; such induced currents, when too high, could havenegative effects on heart’s electric conduction. Starting from a simplified modelling of the heart and making detailedmeasurements of the static magnetic field, we propose a mathematical model for the evaluation of electric currents inducedwithin the heart by static magnetic field, as a consequence of the blood flowing within the arteries and within theheart chambers. Such currents, provoked only by the standing of a patient in a strong static magnetic field, are not avoidableand could be the cause of some heart problems described in medical literature and denounced by patients exposedto static fields above 7.0 T, for diagnostic reasons. Moreover the heart is extremely sensitive to external currents, socurrents induced at an intensity higher than physiological levels could cause malfunctions to the electrical conductionof the organ.