Abnormal magnesium status in patients with cardiovascular diseases

To investigate magnesium status in patients with cardiovascular diseases an d in those presenting high factors for these diseases, we measured the conc entrations of serum total Mg, serum ionized Mg and intra-erythrocyte Mg. Mg is an important cofactor for many enzymes, especially those involved in ph osphate transfer reactions. Mg deficiency has been shown to be associated w ith fatal cardiovascular diseases, as well as with risk factors for these d iseases. Only measurement of the serum concentration of total Mg is routine ly available, but ionized Mg is the physiologically active component. Furth ermore, most of the body's Mg is present in the intracellular space. Subjec ts included patients with ischaemic heart disease (n = 80), cardiac arrhyth mia (n = 60), diabetes mellitus (n = 36), essential hypertension (n = 194) and hypercholesterolaemia (n = 60). The same measurements were made in heal thy controls (30 men and 26 women; mean age 58 +/- 11 years). The serum ion ized Mg concentration was measured with a selective ion electrode. The intr a-erythrocyte Mg concentration was measured by atomic absorption. No gender difference was found for any Mg parameter, nor was age related to any Mg p arameter. The serum albumin concentration was positively correlated only wi th the serum total Mg concentration. Although the serum total Mg concentrat ion was similar in all groups, patients with diabetes mellitus and arrhythm ia had lower serum levels of ionized Mg. Patients with essential hypertensi on exhibited higher intra-erythrocyte Mg concentrations than the healthy co ntrols. Thus the measurement of serum total Mg concentration may obscure th e presence of extracellular Mg deficiency in patients with arrhythmia and d iabetes mellitus. Furthermore, the intracellular accumulation of Mg does no t support the hypothesis of Mg deficiency in patients with essential hypert ension.