Arrhythmias and arrhythmia management in hypertrophic cardiomyopathy

Cardiomyopathies are diseases of the myocardium associated with cardiac dysfunction. According to the World Health Organization (WHO) classification, cardiomyopathies are classified either as primary or secondary cardiomyopathies. Based on morphological and functional criteria, heritable cardiomyopathies are classified into four primary categories including hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), and restrictive cardiomyopathy (RCM). More recently, left ventricular noncompaction (LVNC) syndrome has been recognized as a separate cardiomyopathy. Secondary cardiomyopathies include for example ischemic and hypertensive cardiomyopathy. This chapter focuses solely on HCM, the most common heritable cardiovascular disease (estimated prevalence 1:500) and the most common cause of sudden cardiac death (SCD) in young adolescents and athletes. This chapter discusses HCM’s clinical and genetic substrate, genetic testing and screening, and has particular focus on its arrhythmogenic features and the role and indication of the implantable cardioverter defibrillator (ICD) and prevention of SCD.