To the Editor:
We read with interest the letter by Dr Cheng dealing with our article1 in Revista Española de Cardiología, and thank him for his observations regarding the association between mitral valve prolapse and anorexia nervosa. We appreciate his comments and wish to clarify a few points with regard to our own observations.
Mitral valve prolapse is frequent, with a prevalence of 0.6% to 2.4% in the general population,2 and between 33% and 62% in patients with anorexia nervosa.3,4 The differences in prevalence may be influenced by the clinical and echocardiographic criteria used to diagnose the disorder. In our study, mitral valve prolapse was present in 7 (23.3%) of the patients examined by echocardiography, versus 1 patient (3.3%) in the group of normal control subjects. In all cases the prolapse was mild and clinically asymptomatic. A 24-hour Holter recording disclosed infrequent, isolated supraventricular premature beats in 3 patients, and isolated ventricular premature beats in 1 patient.
Anorexia nervosa is a potentially fatal disease with an annual mortality of 0.56%, i.e., more than 12 times the mortality in young women in the general population. It is estimated that approximately one-third of the patients with anorexia die of cardiac causes, mainly sudden death.5 We agree with Cheng6 that the causes of sudden death in these patients may be associated with prolonged QT interval, increased QT interval dispersion, or mitral valve prolapse. Appropriate treatment, together with improvements in nutritional status, can not only improve mitral valve function, but also ameliorate the alterations in different cardiac parameters.7