A 90-second magnetocardiogram using a novel analysis system to assess for coronary artery stenosis in Emergency department observation unit chest pain patients.

Background: Magnetocardiography (MCG) has been shown to non-invasively detect coronary artery stenosis (CAS). Emergency department (ED) patients with possible acute coronary syndrome (ACS) are commonly placed in an observation unit (OU) for further evaluation. Our objective was to compare a novel MCG analysis system with stress testing (ST) and/or coronary angiography (CA) in non-high risk EDOU chest pain patients.

Methods: This is a prospective pilot study of non-high risk EDOU chest pain patients evaluated with ST and/or CA that underwent a resting 90-second MCG scan between August 2017 and February 2018. A positive MCG scan was defined as having current dipole deviations with dispersion or splitting during the repolarization phase. ST, CA and major adverse cardiac events (MACE) 30 days and 6 months post-discharge assessed.

Results: Of 101 study patients, mean age was 56 years and 53.6% were male. MCG scan sensitivity with 95% CI was 27.3% [7.3%, 60.7%], specificity 77.8% [67.5%, 85.6%], PPV 13.0% [3.4%, 34.7%] and NPV 89.7% [80.3%, 95.2%] compared to ST, and 33.3% [7.5%, 70.7%], 78.3% [68.4%, 86.2%], 13% [5.2%, 29.0%] and 92.3% [88.2%, 95.1%] respectively compared to ST and CA. No patients had positive ST, CA or MACE 30 days and 6 months post-discharge.

Conclusion: This pilot study suggests a resting 90-second MCG scan shows promise in evaluating EDOU chest pain patients for CAS and warrants further study as an alternative testing modality to identify patients safe for discharge. Larger studies are needed to assess accuracy of MCG using this novel analysis system.