2.1 Patients
Between March 2016 and March 2019, consecutive HOCM patients aged ≥ 18 years who underwent septal myectomy with the aid of special surgical instruments in this center were reviewed. Inclusion criteria were the maximum LVOT gradients ≥ 50 mmHg at rest or with provocation and presence of severe limiting symptoms refractory to maximum pharmacologic therapy with non-vasodilating β-blockers and/or calcium channel blockers. Exclusion criteria included: (1) organic mitral valve (MV) lesions (rheumatic, degenerative, ischemic, infective, and mitral annulus calcification); (2) previous valvular surgery; (3) LVOT obstruction secondary to hypertensive heart disease or severe aortic stenosis; (4) concomitant coronary artery disease requiring bypass grafting; (5) concomitant modified Maze procedure; and (6) concomitant obstruction of right ventricular outflow tract requiring enlargement. Patients who underwent septal myectomy via the transseptal approach through right atrium or via the left atrial approach through interatrial sulcus were also excluded.