[beta-Blocking therapy in obstructive hypertrophic cardiomyopathy. Long term results (author's transl)].

34 patients have been controlled after beta-blocking therapy, for a mean period of 5 years. Symptoms and evolution: syncope disappeared, angoy passed from 47% to 23%, dyspnea from 65% to 47%, dizziness from 70% to 54%, weakness from 30% to 37%. A systolic murmur was present in 75% of the cases. Two patients died by heart failure. Phonocardiogram: the systolic murmur was unchanged, like the carotid pulse. Paradoxical splitting of the 2 degrees sound was more frequent, atrial sound unimodified, isometric contraction shortened (60%) and the Q-1 degree sound interval prolonged (90%). Electrocardiogram: 1 degree A/V block appeared in 24% of the cases, complete A/V block in 9%, atrial fibrillation in 3%. Left atrial enlargement was more frequent; left ventricular hypertrophy unchanged. Heart catheterization (10 cases, after a mean period of 5.5 years): left ventricular pressure gradient passed from 80% to 90%; a low cardiac index from 20% to 30%; telediastolic pressure of left ventricle was unmmodified in 10% of cases, more elevated in 50%, less elevated in 40%. Chest X ray: cardiac size was unchanged in 65% of cases, enlarged in 32%; smaller in 3%. In conclusion, symptoms improved in most of the patients; no case of sudden death was observed. Some data however show that the evolution of the myocardiopathy goes on to congestive heart failure and arise doubts on the real usefullness of beta-blocking drugs in the disease.