HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY - CURRENT TREATMENT, INDICATIONS AND RESULTS

Global annual mortality in hospitalized patients with symptomatic hype rtrophic obstructive cardiomyopathy is just under 5%. Several treatmen ts have been proposed for this severe disease in order to improve dias tolic function and reduce the intraventricular obstacle. The aim is to improve symptomatology and prognosis. The mainstay of treatment is dr ug therapy. The negative inotrope and bradytrope action of beta-blocke rs given at medium doses of 160 to 320 mg/day (propranolol) helps decr ease the incidence of dyspnoea chest pain and the frequency of syncope s 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. Calciu m channel inhibitors at a dose of 360 mg/day for verapamil give very f avourable results in patients managed medically and sometimes in those undergoing surgery. Amiodarone is essentially used as an antiarrhythm ic drug in obstructive syndromes complicated by severe ventricular arr hythmias. Wider use is limited due to cardiac and extracardiac side ef fects, Other drugs including disopyramide, diuretics, digitalics and a ntivitamin 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 controv ersy over the most adapted approach, but the most commonly used techni que is currently septal myectomy which reduces the intraventricular gr adient by 80 to 90%. Simple mitral valve replacement gives similar imp rovement in cardiac haemodynamics but exposes the patient to the compl ications inherent with mitral prostheses. Dual chamber sequential paci ng has also been proven to be an effective means of treating hypertrop hic obstructive cardiomyopathy, reducing the risk of sudden death as w ell as symptomatology in selected patients. Apical pre-stimulation usi ng a short atrio-ventricular delay and the paradoxical septal movement induced by right ventricular stimulation decreases the sub-aortic obs truction and thus improves left ventricular performance, This method m ust be confirmed by mid- and long term results. We are in agreement wi th the Mayo Clinic recommendations that surgical myectomy remains the preferred treatment for most patients with severe hypertrophic obstruc tive cardiomyopathy who are unresponsive to medical treatment.