A CASE OF HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY ASSOCIATED WITH AUTONOMIC NERVOUS DYSFUNCTION

Autonomic nervous dysfunction has recently been considered to be an et iological factor in syncope and sudden death in cases of hypertrophic cardiomyopathy. However, the precise mechanism is still unknown. A 73- year-old woman with obstructive hypertrophic cardiomyopathy was hospit alized with complaints of impaired consciousness; faintness 3 to 4 h a fter meals, lightheadedness while walking, and syncope during and afte r defecation and micturition. Faintness was induced by alimentary hypo glycemia related to gastrectomy performed 5 years previously. Lighthea dedness and syncope were accounted for by autonomic nervous failure co mbined with an impairment of al-adrenoceptor in vasoconstriction and t he carotid sinus hypersensitivity which accompanied preceding events s uch as abdominal pain, defecation and micturition, which could enhance the vagally-mediated baroreceptor reflex.