1. Partial Zone of Apposition Closure in Atrioventricular Septal Defect: Are Papillary Muscles the Clue 
Timothy M. Colen, MBBS, Nee S. Khoo, MBChB, David B. Ross, MD, Jeffrey F. Smallhorn, MBBS 
The Annals of Thoracic Surgery 
Volume 96, Issue 2, Pages (August 2013)
DOI: /j.athoracsur
Copyright © 2013 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
This montage is from case number 3 where there was an eccentric zone of apposition in the left atrioventricular valve. (A) and (B) demonstrate the left atrioventricular valve from the left ventricular aspect. Note the eccentric zone of apposition indicated by the black arrow. The 2 white stars demonstrate the commissures. Note the blunt superior-mural commissure compared with the well-formed inferior-mural one. (A) shows the anterolateral papillary muscle as it inserts higher into the superior bridging leaflet. This is also seen in (D), a two-dimensional short axis image of the left atrioventricular valve. Note the thick papillary muscle is seen at that level, unlike its postero-medial counterpart. (C) is a simulated surgical view showing the eccentric zone of apposition, as indicated by the black arrow. Note the connecting tongue of tissue between the 2 bridging leaflets. (AO = aorta; IBL = inferior bridging leaflet; I = inferior; ML = mural leaflet; PAP = anterolateral papillary muscle; RAVV = right atrioventricular valve; RV = right ventricle; S = superior; SBL = superior bridging leaflet.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2013 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
These images are from case number 1, as seen preoperatively. (B) shows a two-dimensional short axis view of the left atrioventricular valve, and demonstrates a similar appearance to that seen in case number 3, Figure 1. Note the black star, which represents the thickened anterolateral papillary muscle (ALPM), which appears to be stuck to the superior bridging leaflet (SBL). (A) is a real-time three-dimensional echocardiography image (RT3D) as seen from the left ventricular (LV) aspect. The black star is on the ALPM, which can be seen to fuse with the superior bridging leaflet (SBL) having very short chords and a blunt superior-mural commissure, unlike the well-formed inferior-mural commissure. (I = inferior; IBL = inferior bridging leaflet; LVOT = left ventricular outflow tract; ML = mural leaflet; PMPM = posteromedial papillary muscle; RV = right ventricle; S = superior; SBL = superior bridging leaflet.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2013 The Society of Thoracic Surgeons Terms and Conditions

4. Fig 3
These images were taken during the early postoperative period in case number 1. They are seen in the multiplanar reconstruction, or multiplane reformatting image, which represents simultaneous images of the left atrioventricular valve seen in different planes, as well as a real-time three-dimensional echocardiography (RT3D) reconstructed image. (D) is the RT3D image, seen from the left atrial view, and shows the fully sutured zone of apposition, outlined by the white stars. Note that in systole there is a significant area of non-coaptation indicated by the black arrow. The main site of malcoaptation is to the left of the sutured zone of apposition. (C) is a RT3D color Doppler image demonstrating the significant regurgitant jet, which arose from the site of malcoaptation. Note there is also a smaller jet, which arose from the area of the sutured zone of apposition. (A) and (B) are two-dimensional images at right angles to each other. The white ellipse indicates the anterolateral papillary muscle which courses toward the left ventricular outflow tract (LVOT), thus tethering the superior bridging leaflet. (ALPM = anterolateral papillary muscle; AO = aorta; IBL = inferior bridging leaflet; LA = left atrium; LV = left ventricle; ML = mural leaflet; SBL = superior bridging leaflet; SEPT = interventricular septum.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2013 The Society of Thoracic Surgeons Terms and Conditions

5. Fig 4
This montage is from case number 5 and shows (A) a preoperative real-time three-dimensional echocardiography (RT3D) image and (B) the autopsy specimen. The autopsy specimen shows the left ventricle (LV) with the septal surface exposed. The primum patch (Prim) is evident, as is the limited closure of the zone of apposition (see the single stitch at the base). Note the prominent anterolateral papillary muscle (ALPM) as outline by the white arrows that inserted directly onto the superior bridging leaflet (SBL), as indicated by the 2 black lines. The left ventricular outflow tract (LVOT) cannot be seen in the specimen and lies beneath the section of left ventricular free wall that has been moved to the side. The RT3D image, which is preoperative, has been manipulated and oriented to show a similar view and demonstrates the superior (SBL) and inferior bridging leaflets (IBL) toward the end of diastole. The zone of apposition can seen as can the crest of the interventricular septum, which is indicated by the white star. Note the Prim defect and the dominant ALPM, which as in the specimen inserts directly into the superior bridging leaflet (black lines). (I = inferior; S = superior.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2013 The Society of Thoracic Surgeons Terms and Conditions