[Risk stratification for sudden death in hypertrophic cardiomyopathy].

The natural history of hypertrophic cardiomyopathy (HCM) is extremely heterogeneous. Many patients remain asymptomatic throughout life, some develop severe symptoms of heart failure, but others die suddenly, often in the absence of previous symptoms and at a young age. Therefore, identification of those patients at high risk of sudden death represents a major clinical problem and has become an even greater challenge since the implantable cardioverter-defibrillator (ICD) has proved to be highly effective in preventing sudden death in HCM. Patients who have survived a cardiac arrest, or one or more episodes of sustained ventricular tachycardia, are considered to be at high risk and are candidates for an ICD. However, this patient subset represents a small proportion of the HCM population. The greatest difficulty concerns the identification of high risk patients who are candidates for primary prevention of sudden death with a prophylactic ICD. Decisions are based on generally accepted clinical markers which are associated with increased risk, including: family history of sudden death, extreme left ventricular (LV) wall thickness ( > or =30 mm), nonsustained ventricular tachycardia on Holter monitoring, unexplained (non-neurocardiogenic) syncope particularly in young patients, and hypotensive blood pressure response to exercise. Patients with end-stage HCM or a LV apical aneurysm represent important arrhythmogenic subsets also associated with substantially increased risk. Multiple or single strong risk markers are associated with increased sudden death risk and justify consideration for a prophylactic ICD.