[Hypertrophic obstructive cardiomyopathy: current treatment, indications and results]

Global annual mortality in hospitalized patients with symptomatic hypertrophic obstructive cardiomyopathy is just under 5%. Several treatments have been proposed for this severe disease in order to improve diastolic function and reduce the intraventricular obstacle. The aim is to improve symptomatology and prognosis. The mainstay of treatment is drug therapy. The negative inotrope and bradytrope action of beta-blockers given at medium doses of 160 to 320 mg/day (propranolol) helps decrease the incidence of dyspnoea chest pain and the frequency of syncopes in 30 to 70% of the patients. Higher doses up to 1 g per day may be helpful in certain patients, but with the risk of sudden death. Calcium channel inhibitors at a dose of 360 mg/day for verapamil give very favourable results in patients managed medically and sometimes in those undergoing surgery. Amiodarone is essentially used as an antiarrhythmic drug in obstructive syndromes complicated by severe ventricular arrhythmias. Wider use is limited due to cardiac and extracardiac side effects. Other drugs including disopyramide, diuretics, digitalics and antivitamin K agents also have a role to play. The aim of surgery is to alleviate the intraventricular obstacle, correct mitral regurgitation and increase left ventricular compliance. There has been much controversy over the most adapted approach, but the most commonly used technique is currently septal myectomy which reduces the intraventricular gradient by 80 to 90%. Simple mitral valve replacement gives similar improvement in cardiac haemodynamics but exposes the patient to the complications inherent with mitral prostheses. Dual chamber sequential pacing has also been proven to be an effective means of treating hypertrophic obstructive cardiomyopathy, reducing the risk of sudden death as well as symptomatology in selected patients. Apical pre-stimulation using a short atrio-ventricular delay and the paradoxical septal movement induced by right ventricular stimulation decreases the sub-aortic obstruction and thus improves left ventricular performance. This method must be confirmed by mid- and long term results. We are in agreement with the Mayo Clinic recommendations that surgical myectomy remains the preferred treatment for most patients with severe hypertrophic obstructive cardiomyopathy who are unresponsive to medical treatment.