Hypertrophic cardiomyopathy: prevention of sudden cardiac death

Sudden cardiac death (SCD) secondary to ventricular arrhythmias is the most common mode of death in hypertrophic cardiomyopathy (HCM) and can be effectively prevented with an implantable cardioverter defibrillator (ICD). The risk of SCD in HCM relates to the severity of the phenotype and regular risk stratification is an integral part of routine clinical care. For the primary prevention of SCD, risk stratification involves the assessment of seven readily available clinical parameters (age, maximal left ventricular wall thickness, left atrial diameter, left ventricular outflow tract gradient, non-sustained ventricular tachycardia, unexplained syncope, and family history of SCD) which are used to estimate the risk of SCD within 5 years of clinical evaluation using a statistical risk prediction model (HCM Risk-SCD). The 2014 European Society of Cardiology Guidelines provide a framework to aid clinical decisions and consider patients with a 5-year risk of SCD of less than 4% as low risk and recommend regular assessment while those with a risk of 6% or higher should be considered for an ICD. In patients with an intermediate risk (4% to <6%) ICD implantation may also be considered after taking into account age, co-morbid conditions, socioeconomic factors, and the psychological impact of therapy. Survivors of ventricular fibrillation arrest should receive an ICD for secondary prevention unless their life expectancy is less than 1 year. Following device implantation, patients should be followed up for device- and disease-related complications, particularly heart failure and cerebrovascular disease.