Erythrocyte magnesium in symptomatic patients with primary mitral valve prolapse: relationship to symptoms, mitral leaflet thickness, joint hypermobility and autonomic regulation.

The availability of methods to assess intracellular magnesium has caused great interest in the biologic role of this ion. Measurement of total intracellular erythrocyte magnesium (RBC Mg) by atomic absorption spectroscopy in 94 prospectively studied patients (87 female, age 44 +/- 12 years) with symptomatic primary mitral valve prolapse diagnosed by strict echocardiographic and clinical criteria (Perloff) identified 35 patients with normal (2.12 +/- 0.16 mmol/l) and 59 with low (1.51 +/- 0.31 mmol/l) RBC Mg (mean +/- SD). The two groups did not differ in demographic or clinical characteristics, incidence of thick mitral leaflets, joint hypermobility (by Beighton-Horan score), chest pain, fatigability, palpitations, anxiety, depression, orthostatic hypotension, autonomic test results or plasma catecholamines. Muscle cramps and migraines were more frequent in Mg-deficient patients (but p < 0.05). We postulate that the lack of differences between the groups may be due to poor correlation of RBC Mg with Mg concentration of tissue pools.