Tangential / angled view also known as the commissural view is commonly used to assess the mitral valve, which  offers an oblique perspective and can help in clarifying and magnifying leaflet details and characteristics, especially in assessing the commissures. The non-surgical views, and in particular the so-called “angled or tangential views” first described by Biaggi, et al provide additional data compared to the surgical view. These views allow a better perception of the protrusion of the prolapsing tissue into the left atrium and at the same time visualization of the commissural areas. In general, the variable perception of protrusion of flail segments in degenerative mitral valve disease depends on a smart combination of an angled view with a light source tangential to the prolapsing tissue and a certain degree of transparency known as glass view.

Atrial view-  / Surgical view: The most familiar and applied 3D view is the atrial view, obtained with the probe in the mid-oesophageal position. It is also called as the ‘surgical view’ for the similar perspective of the valve when exposed by the surgeon. The landmarks to correctly orientate mitral valve in this view are the aortic valve and the left atrial appendage, located respectively in the superior and lateral parts of the screen. In this view, the anterior leaflet (AL) appears  in the superior part of the screen, whereas the posterior leaflet (PL) appears in the inferior part. From the surgical echocardiographic view, it is possible to appreciate a straight AL hinge line in continuity with the atrial wall, while the mitral-aortic curtain is visualized only from the ventricular perspective. 

The ‘ventricular view’ allows to appreciate different details. From this perspective,  the antero-lateral commissure is displayed on the right and the postero-medial commissure on the left.  In this view, the mitral-aortic curtain can be appreciated in continuity with the left interleaflet aortic triangle, located between the left and non-coronary cusps.

 3D ‘longitudinal view’, includes the left ventricular cavity and allows to appreciate the chordal apparatus and papillary muscles anatomy and motion. Most chordae arise from the apices of the papillary muscles, branch, and then attach to both the leaflets.

Hence, the correct answer is option ‘d’.

3D TEE mitral valve views: (A) surgical view, (B) ventricular view, (C) longitudinal view, and (D) commissural view. (AC = antero-lateral commissure, AL = anterior leaflet, Ao = aortic valve, LAA = left atrial appendage, MAo C = mitral-aortic curtain, PC = postero-medial commissure, PL = posterior leaflet).

References

1. Tommaso Viva, Corrado Fiore, Patrizio Lancellotti, Three-dimensional assessment of  the mitral valve in clinical practice, European Heart Journal - Imaging Methods and Practice,  2025, qyaf128, https://doi.org/10. 1093/ehjimp/qyaf128

 2.  Faletra FF, La Franca E, Leo LA, Sade LE, Katz W, Musumeci F, Gandolfo C, Pilato M, Cipriani M. The key role of 3D TEE in assessing the morphology of degenerative mitral valve regurgitation. J Cardiovasc Dev Dis 2024;  28:342. doi: 10. 3390/jcdd11110342.