Mitral Arcades Encountered Unexpectedly During Open Heart Surgery

Mitral Arcade (MA) is a rare congenital structural heart disease associated with the mitral valve complex. The pathology of this anomaly is characterized by the absence or diminution of chordae to the anterior mitral leaflet replaced by direct attachment of elongated papillary muscles to the leaflet. Layman et al. (1) identified four indications of mitral arcades which include adequate size of the mitral valve orifice, papillary/chordae morphology as described above, narrowing or complete obliteration of interchordal spaces and relatively better differentiation of posteriorly attaching chordae. MA valve repair surgery is a complex procedure (2, 3) and the discovery of this anomaly unexpectedly intraoperatively poses surgical challenges. We present two adult patients in whom MA eluded preoperative workup diagnosis and was encountered unexpectedly intraoperatively. MA can be underdiagnosed (4) and further imaging studies may help diagnosis when the mechanism of mitral stenosis or regurgitation is not clear.