THE PARACHUTE-LIKE ASYMMETRIC MITRAL-VALVE AND ITS 2 PAPILLARY-MUSCLES

Objectives: The morphologic features of parachute-like asymmetric mitr al valves are described to discriminate this anomaly from parachute mi tral valves, Background: Mitral valves with unifocal attachment of cho rds have been called ''parachute valves,'' independent of the number o f papillary muscles, Therefore the anomaly involving two papillary mus cles has not received separate attention, Methods: The gross anatomy o f 29 mitral valves with focalized attachment of chords was studied, Re sults: In 28 of the autopsy specimens asymmetric mitral valves with tw o papillary muscles were present, and one of the muscles was elongated , located higher in the left ventricle with its tip reaching to the an ulus, and attached at both its base and lateral side to the left ventr icular wall, The valve leaflets could be directly attached to this abn ormal muscle that received few chords or, in three hearts: no chords a t all, resulting in an oblique and eccentric orifice, Because of the f ocalized attachment of chords to one of the two papillary muscles, we call this malformation ''parachute-like asymmetric mitral valve.'' We found only one ''true parachute mitral valve,'' that is, one having a single papillary muscle that received all chords, Conclusions: The mor phologic features of asymmetric mitral valves are essentially differen t from those of true parachute valves, A distinction between these two anomalies will contribute to recognition by the pediatric cardiologis t and surgeon.