Sudden cardiac death (SCD) continues to be a major issue in patients with hypertrophic cardiomyopathy (HCM), although the incidence may be decreasing because of primary prevention treatment with implantable cardioverter defibrillators (ICD). The young are at particular risk for SCD, while those over 60 are rarely affected by SCD. The American Heart Association Guideline was updated in 2020, and several changes in risk stratification are noted. Currently, an ICD is recommended for resuscitated SCD and/or those with sustained ventricular tachycardia. An ICD is reasonable (2a) for patients with one of the following: massive hypertrophy (≥ 3 cm), unexplained syncope, a family history of SCD, apical aneurysm, or LVEF ≤50%. For pediatric patients with NSVT, an ICD is reasonable (2a), while one may be considered for adults (2b). Finally, for those with extensive gadolinium enhancement on MRI, an ICD may be considered (2b). In the ESC guidelines, a calculator is used which incorporates age, LV thickness, LA size, and LVOT gradients as continuous variables, as well as FMH SCD, NSVT, and syncope as binary variables.