Echocardiographic Perspectives on Transient Mitral Regurgitation After Septal Myectomy

Mitral regurgitation (MR) following septal myectomy for hypertrophic obstructive cardiomyopathy may persist despite relief of systolic anterior motion and left ventricular outflow tract obstruction. Clinical observations suggest that a subset of postoperative MR may be transient and related to posterior leaflet restriction rather than structural mitral valve abnormality. The investigators will perform a retrospective single-centre cohort study of patients undergoing septal myectomy between 2022 and 2025. Intraoperative post-bypass transesophageal echocardiograms and predischarge transthoracic echocardiograms will be independently reviewed to assess MR severity and mechanism. The investigators hypothesize that a substantial proportion of moderate-or-greater postoperative MR resolves before discharge, supporting a conservative approach to mitral valve intervention and improving intraoperative echocardiographic decision-making.

Inclusion Criteria: * Adult patients (≥18 years) * Undergoing septal myectomy for HOCM * Availability of intraoperative post-cardiopulmonary bypass TEE images * Availability of predischarge TTE Exclusion Criteria: * Concomitant primary mitral valve disease due to structural abnormalities, prior ischemic MR or previous MV intervention (repair or replacement) * Inadequate echocardiographic image quality precluding MR assessment * Patients without paired TEE and TTE studies