1. Is the Morphologic Mitral Valve in Discordant Atrioventricular Connections Always Normal? 
Hideki Uemura, MD, Iki Adachi, MD, Karen P. McCarthy, BS, Masahiro Koh, MD, Siew Yen Ho, PhD 
The Annals of Thoracic Surgery 
Volume 86, Issue 4, Pages (October 2008)
DOI: /j.athoracsur
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
Diagrams of the inlet valve guarding the morphologic left ventricle in hearts with discordant atrioventricular connection. The anticipated standard pattern is a mirror image of the mitral valve in the normally structured heart, and was seen in 6 hearts. In another heart with mirror image atrial arrangement, orientation of the mitral valve was similar to the normal mitral valve. Abnormalities in tension apparatus with solitary or dual papillary muscles were present in 17 hearts having a usual apposition between the anterior and the posterior (mural) leaflets. (PM = papillary muscles.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
A picture of the mitral valve in a heart with criss-crossing atria to ventricular inflows. The display is orientated to show the mitral structures as if in a normally structured heart. The anterior leaflet and the mural leaflet of the mitral valve appeared to be fairly normal. The leaflets were tethered well as seen in the mitral valve of the normally structured heart. The anterior papillary muscle had an ordinary shape and arose from the apical free wall of the morphologic left ventricle as normal. The posterior papillary muscle was more conjugating and had broader attachment to the ventricular wall. A thin muscle bar (arrow) reached to the annular attachment of the leaflets, and behind the bar there was little space between the annular attachment of the leaflets and the origin of the broad-based papillary muscle. (MV = mitral valve; PM = papillary muscles.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

4. Fig 3
Diagrams of the mitral valve with a usual pattern of closure of the leaflets and multiple papillary muscles. (PM = papillary muscles.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

5. Fig 4
Diagrams of the trifoliate or quadrifoliate mitral valve in 5 hearts. The papillary muscles were also abnormal. (PM = papillary muscles.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

6. Fig 5
(A) Viewed from the right atrium, this mitral valve was trifoliate (blue arcs) and supported by a pair of fused papillary muscles located postero-inferiorly. The asterisks indicate artifactual incisions. (B) The papillary muscles are separated and the valve displayed to show adhesion of the medial part of the mural leaflet to the ventricular septum (triangle). (C) The left ventricular outflow tract is opened to show the presence of a muscular infundibulum (double-headed arrow). A membranous aneurysm (small arrow) and adhesion of the mitral leaflet occludes a ventricular septal defect leaving a slit-like interventricular communication.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions