Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that is associated with sudden cardiac death. Myofiber disarray is a key feature of HCM but it is not clear how much it affects the heart function. To resolve this issue, we are developing patient specific computational heart model to investigate the effects of myofiber disarray and the heterogeneity of regional wall thickness on left ventricular function in HCM.