Commissure leaflet prolapse closely mimics anterior mitral leaflet perforation in 2-D image of transesophageal echocardiography.

Background: Precise diagnosis of mitral valve regurgitation is challenging, particularly for distinguishing between commissure leaflet prolapse and anterior leaflet perforation, based exclusively on 2-dimensional (2-D) imaging by transesophageal echocardiography. CASE 1: Two mitral regurgitation jets suggesting anterior leaflet perforation, but no regurgitation orifices, were observed in the mid esophageal (ME) 4-chamber view. Multiple 2-D and 3-dimensional (3-D) images revealed prolapse of the anterior (A3) leaflet and posterior commissure, not anterior leaflet perforation. CASE 2: A regurgitation jet suggesting an anterior leaflet prolapse with a regurgitation orifice was observed in ME long-axis view. Multiple 2-D and 3-D images showed only anterior commissure prolapse, but no signs of anterior leaflet perforation.

Conclusions: A regurgitant jet caused by commissure leaflet prolapse closely resembles anterior leaflet perforation in 2-D imaging. Careful evaluation of multiple 2-D and 3-D images, as well as of the regurgitation orifices, is crucially important for making an accurate diagnosis.