A Unique Cause of Mitral Regurgitation–Mitral Commissural Prolapse

A 65-year-old female patient was referred following worsening failure symptoms.Transthoracic echocardiography (TTE) demonstrated a prolapsed posterior leaflet of the mitral valve (MV).However, there was a widely spreading mitral regurgitation (MR) jet, casting some suspicion on the exact etiology of the MR.Transesophageal echocardiography, using three-dimensional (3D) reconstruction and multi-planar imaging, revealed changes suggestive of a postero-medial commissure prolapse.Commissural prolapse is an often-overlooked cause of MR.Accurate diagnosis is only achieved in approximately one-third of cases using two-dimensional TTE as conventional views are often unable to visualize the exact mechanism of MR.Meticulous assessment and early recognition of MV commissural prolapse, or flail, is important for accurate diagnosis and pre-procedural or surgical planning.Alongside some unique features to suggest the presence of commissural prolapse, we hope to highlight the pivotal role of multi-planar imaging and 3D reconstruction in such a diagnosis.