Ionized Magnesium: Interpretation and Interest in Atrial Fibrillation

Abstract

Background: Magnesium (Mg) is often used to manage de novo atrial fibrillation (AF) in the emergency department (ED) and intensive care unit (ICU). Point of care measurement of ionized magnesium (iMg) allows a rapid identification of patients with impaired magnesium status, however, unlike ionized calcium, the interpretation of iMg is not entirely understood. Thus, we evaluated iMg reference values, correlation between iMg and plasmatic magnesium (pMg), and the impact of pH and albumin variations on iMg levels. Secondary objectives were to assess the incidence of hypomagnesemia in de novo AF. Methods: A total of 236 emergency department and intensive care unit patients with de novo AF, and 198 control patients were included. Reference values were determined in the control population. Correlation and concordance between iMg and pMg were studied using calcium (ionized and plasmatic) as a control in the whole study population. The impact of albumin and pH was assessed in the discordant iMg and pMg values. Lastly, we assessed the incidence of ionized hypomagnesemia (hypoMg) among de novo AF. Results: The reference range values established in our study for iMg were: 0.48–0.65 mmol/L (the manufacturers were: 0.45–0.60 mmol/L). A strong correlation was observed between pMg and iMg (r = 0.85), but, unlike for calcium values, there was no significant impact of pH and albumin in iMg/pMg interpretation. The incidence of hypoMg among de novo AF patients was 8.5% (12.7% using our ranges). When using our ranges, we found a significant link (p = 0.01) between hyopMg and hypokalemia. Conclusion: We highlight the need for more accurate reference range values of iMg. Furthermore, our results suggest that blood Mg content is not identical to that of calcium. The incidence of ionized hypomagnesemia among de novo AF patients in our study is 8.5%.

Dysmagnesemia Measured by Ionized and Total Body Concentrations Among Medically Hospitalized Patients: Incidence, Clinical Characteristics, and Health Outcomes - A Prospective Cohort Study

“…These ndings support to the utilization of point-of-care analyzers for assessing iMg status in hospitalized patients, particularly when timely clinical decisions are necessary to guide patient management, including cases involving cardiac arrhythmia. (20) In the present study, signi cant discrepancies were observed in the prevalence of dysmagnesemia when comparing the use of iMg and tMg concentrations. Which is in concordance with previous studies.…”

“…(13) One study found that the prevalence of hypomagnesemia de ned as iMg concentrations less than 0.48 mmol/L, was 12.7% in patients presenting to the emergency department with de novo AF. (20) Another study including 31 patients following abdominal surgery, found that both tMg and iMg concentrations decreased during surgery, with a strong correlation between both. (13) Overall, hypermagnesemia is increasingly recognized as an issue among hospitalized patients.…”

The Stability of Analytes of Ionized Magnesium Concentration and Its Reference Range in Healthy Volunteers

“…Additionally, blood samples collected in lithium heparinized syringes from 125 healthy adults from the United Kingdom and stored in Sarstedt Monovette ® serum gel blood collection tubes, resulted in iMg reference range of 0.45–0.60 mmol/L [ 18 ]. Furthermore, a French study, using the direct ISE technique for 80 patients who visited the emergency department, established a reference range of 0.48 to 0.65 mmol/L [ 24 ].…”

“…However, the results were inconsistent, most likely due to pathophysiological interference and variation in the analytical methodologies [ 23 ]. Furthermore, the stability of analytes obtained for determining iMg concentration has not been established [ 24 ]. Such discrepancies in measurement methods and questionable stability, iMg concentration, and its use as a guide in treatment are not common in clinical practice.…”

Changing trend of neonatal Ca/P/Mg status in a Chinese population

“…In the past, a number of studies were performed to investigate the association between Ca/P/Mg levels and various diseases. Mg was closely with the risk of cardiovascular diseases ( 40 ). Decreased level of Mg was linked to the impaired glucose homeostasis, insulin function and inflammation ( 41 ).…”