The role of magnetocardiography in the diagnosis and efficacy assessment of coronary microvascular dysfunction

Objective To explore the non-invasive diagnostic criteria of magnetocardiography (MCG) for coronary microvascular dysfunction (CMVD), and its value in dynamically assessing drug treatment for CMVD.

Methods Patients who presented with chest tightness or chest pain at Zhongshan Hospital, Fudan University from September 2024 to March 2025 were consecutively enrolled, and all of whom had non-obstructive coronary arteries on angiography. Using the coronary angiography-derived index of microcirculatory resistance (caIMR) as the gold standard, patients were divided into a normal microcirculation group (caIMR≤40 U) and a CMVD group (caIMR＞40 U). MCG testing was performed using a domestic device (MD-U041001, Mind Medical). Patients in the CMVD group received adenosine treatment and underwent repeat MCG after medication. Differences in MCG parameters between the two groups were analyzed, and a diagnostic model was established. The value of the diagnostic model was analyzed using receiver operating characteristic (ROC) curves.

Results A total of 311 patients were included, with 135 in the normal microcirculation group and 176 in the CMVD group. The CMVD group had a significantly higher proportion of males (61.9% vs 47.4%, P＝0.012), and lower high-density lipoprotein cholesterol (HDL-C) levels (1.16±0.31 mmol/L vs 1.24±0.29 mmol/L, P＝0.029) than the normal group. Eleven MCG parameters showed significant differences between the two groups (P＜0.05), among which increased values of mfm_QR_epav, mfm_RS_epmse, space_zeroRTrot, as well as decreased value of mfm_QR_v1 were independent predictors of CMVD. The diagnostic model based on these 11 MCG parameters yielded an area under the curve (AUC) of 0.688 (95%CI 0.629-0.747). The integrated diagnostic model combining clinical risk factors (male, smoking history, HDL-C) with MCG parameters had an AUC of 0.701 (95%CI 0.643-0.759). After adenosine treatment, patients in the CMVD group showed significant decreases in mfm_QR_epav (P＝0.010), mfm_RS_sad (P＝0.013), and mfm_RS_epmse (P＝0.046).

Conclusions The model based on MCG parameters demonstrates good diagnostic ability for CMVD; dynamic changes in MCG parameters following adenosine intervention may serve as potential objective indicators for evaluating microcirculatory treatment efficacy.