Trileaflet Mitral Valve as Unusual Contributor to Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy.

BACKGROUND

Mitral valve abnormalities are increasingly recognized as contributors to left ventricular outflow tract obstruction (LVOTO) in obstructive hypertrophic cardiomyopathy (oHCM). Although trileaflet mitral valves have been reported previously in patients with oHCM, this case demonstrates how detailed segmental echocardiographic phenotyping identified distinct mechanisms of dynamic LVOTO, enabling an individualized repair.

CASE SUMMARY: A 48-year-old man with oHCM was found to have a trileaflet mitral valve contributing to LVOTO in addition to systolic anterior motion.

DISCUSSION: Careful anatomical and functional assessment distinguished this anomaly from pseudo-trileaflet variants and enabled anatomy-directed repair while preserving the native valve.

TAKE-HOME MESSAGES: In oHCM, comprehensive 2D and 3D imaging should define the mechanism of LVOTO and mitral regurgitation rather than simply identify anatomical abnormalities. Detailed mitral valve phenotyping can distinguish a true congenital trileaflet morphology from pseudo-trileaflet variants and reveal leaflet-specific mechanisms of obstruction. Mechanism-based imaging helps surgeons choose the most appropriate valve-preserving repair for each patient's valve abnormality.