J Thorac Cardiovasc Surg 157 (1): 306 - 315.e3, 2019. doi: 10.1016 / j. jtcvs.2018.08.062 Key Points Hypertrophic cardiomyopathy is usually due to one of numerous genetic mutations that cause various types of ventricular hypertrophy that restrict filling (ie, cause diastolic dysfunction) and sometimes obstruct LV outflow.