[Magnesium deficiencies in cardiovascular diseases].

Plasma (pl), red blood cell (ery) and urinary magnesium (Mg) concentrations were measured by spectrophotometry in over 300 patients at the Cardiology Department of Broussais Hospital. Other biological parameters, including pl and ery potassium, calcium and phosphate concentrations were measured simultaneously. In a control group (54 subjects) the mean pl Mg was 0,851 mmol/l in men and 0,819 mmol/l in women; mean ery Mg was 2,12 mmol/l and 2,09 mmol/l respectively. Magnesium depletion was observed in several pathological cardiovascular conditions: -- mitral valve prolapse: the Mg levels were significantly lower in women (19 cases) (pl Mg 0,740 mmol/l; ery Mg 1,83 mmol/l: p less than 0,001); the deficit was less pronounced in men: pl Mg 0,829 mmol/l, p less than 0,01, and ery Mg 2,01 mmol/l (NS); -- recurrent junctional tachycardia (21 cases): the Mg levels were significantly lower than normal: pl Mg = 0,796 mmol/l in men and 0,763 mmol/l in women; ery Mg = 1,93 and 1,88 mmol/l, respectively; -- coronary insufficiency (86 cases): pl Mg = 0,821 mmol/l in men and 0,768 mmol/l in women (p less than 0,001). In a subgroup with coronary spasm (22 cases), the mean ery Mg was decreased (2,01 mmol/l, p less than 0,05); -- unstable or labile hypertension (24 cases): the decrease was significant, especially in women (pl Mg = 0,796 mmol/l, ery Mg = 1,88 mmol/l). These magnesium deficits were sometimes associated with a low pl Ca, and often associated with a low ery K although pl K was usually raised. In some privileged cases of cardiac arrhythmia and coronary spasm, intravenous Mg repletion was beneficial but did not affect plasma concentrations. The role of magnesium depletion in cardiovascular disease remains obscure and requires further study.