A unique presentation of systolic anterior motion of the mitral valve in a patient with obstructive hypertrophic cardiomyopathy and recurrent syncope: a case report

Background Systolic anterior motion (SAM) of the mitral valve is a hallmark feature of hypertrophic obstructive cardiomyopathy (HOCM) and a primary cause of dynamic left ventricular outflow tract obstruction. This case report highlights an unusual presentation of SAM associated with acute haemodynamic collapse.Case summary A 36-year-old male with HOCM presented with recurrent episodes of syncope. After a multidisciplinary evaluation, he underwent percutaneous intramyocardial septal radiofrequency ablation (PIMSRA). Approximately 1-h post-procedure, the patient developed severe haemodynamic collapse. Transthoracic echocardiography revealed abnormal proximal displacement of the anterior mitral valve leaflet, bringing it into close proximity with the septum. The patient was treated emergently with high-dose intravenous norepinephrine, stabilizing his condition. At the 18-month follow-up, the patient reported no recurrence of syncope.Discussion Proximal displacement of the anterior mitral leaflet, a rare and severe form of SAM, is an uncommon yet critical complication associated with haemodynamic collapse and syncope. This phenomenon warrants heightened attention during PIMSRA for the treatment of HOCM.