Serum Magnesium Levels in Acute Myocardial Infarction:A Cross-Sectional Observational Study

Abstract

Background: Previous studies have suggested that acute myocardial infarction (AMI) may cause magnesium to shift from the extracellular to the intracellular compartment, resulting in transient reductions in serum magnesium. In the literature this shift is mechanistically documented; however, whether it is reliably detectable via single-point admission serum total Mg remains unclear. Hypomagnesemia has been associated with cardiovascular disease in prior studies; therefore, a similar association might be expected in AMI patients. The aim of the study was to evaluate admission serum magnesium levels and their association with Troponin I levels, comorbidities, and clinical subgroups among AMI patients admitted to a tertiary hospital in Bangladesh. The study aimed to evaluate whether admission serum magnesium levels are associated with AMI severity and whether the conventional association between hypomagnesemia and cardiovascular disease warrants further re-evaluation. Methods: This was a cross-sectional study conducted in an inpatient cardiology ward at Mitford hospital in Bangladesh. The AMI patients were enrolled between 2022 and 2024. Admission serum Mg (mg/dL), Troponin I (pg/mL), ECG findings, comorbidities, and lifestyle variables were recorded. Statistical analyses were conducted using Python 3.11. Pearson/Spearman correlations, independent samples t-tests, one-way ANOVA, and one-sample t-test (reference 2.0 mg/dL) were applied. Results: Mean serum Mg was 2.050 ± 0.189 mg/dL (median 2.02; IQR 1.97-2.11). 98% of patients had Mg within the normal reference range (1.7-2.4 mg/dL). No significant correlation was found between serum Mg and Troponin I (r = -0.017, p = 0.910; = 0.058, p = 0.692). Serum Mg did not differ significantly by hypertension, prior MI, diabetes mellitus, or post-MI complications. A significant ANOVA finding by physical activity group (F = 3.804, p = 0.030) is attributed to dietary/medication confounding, multivariate analysis would be required to isolate the specific impact of physical activity level which was beyond the scope of this study. Conclusion: Serum magnesium levels at admission do not reliably predict the severity of myocardial injury in acute myocardial infarction. While single-point serum tests have limited utility, recent data show a U-shaped risk curve where both very low and high-normal magnesium levels correlate with adverse patient outcomes.

Bangladesh J Medicine 2026; 37(3): 227-233