Idiopathic magnesium deficiency in mitral valve prolapse

Latent tetany, normocalcemic latent tetany or spasmophilia, was first described by Klotz.¹ Response of the neuromuscular hyperexcitability to oral magnesium (Mg) therapy, together with lower than normal mean plasma and red blood cell Mg found by Durlach¹ in these patients, suggests that this nosologic entity is the most frequent neuromuscular expression of primary chronic Mg deficiency. Luccioni and Gerard² and Durlach et al³ found that mitral valve prolapse (MVP) complicates the evolution of at least one-third of cases of latent tetany. Lower than normal red blood cell Mg values were found in the patients with complicated courses. Chest pain atypical for angina pectoris, palpitations, syncope and presyncope, dyspnea without orthopnea, fatigue, anxiety neurosis and panic attacks-symptoms common to both MVP and latent tetany-were found to be responsive to oral Mg therapy.⁴ In the 17 patients described herein with echocardiographically proved MVP, lower than normal mean lymphocyte Mg concentration and greater than normal Mg retention in the intravenous Mg-load test were found. These findings suggest the existence of a Mg deficiency state in this condition.