LAO caudal view : Relation of left coronary artery to cardiac chambers
July 10, 2025 by dr s venkatesan
Though we do coronary angiogram and complex angioplasties day in day out, we rarely get oriented , to the exact anatomical relations of individual coronary artery with reference to cardiac chambers. When I asked my fellows, to identify , the chambers on either side of left main at its bifurcation , none of them were confident. (I must confess, I was also in the same page of vagueness till I saw this clip .)
A brief anatomy of LCA
*LMCA after emerging from the aortic sinus, the travels a short distance, usually between 5 to 15 mm, towards the left side of the heart. During this initial course, the LMCA passes posterior to the pulmonary trunk. The left main is also closely related to RVOT especially the posterior and septal aspect. Once bifurcated , the LCX is related to LAA.
LAO caudal view : The most familiar, and usually the first shot we do.
This video clip is posted here with the courtesy of Dr. Srinivasa Prasad, from Sri Chitra Thirunal Institute of Cardiac Science, Thiruvananthapuram, India from his you tube post.
Note : In LAO caudal view, we are looking from the left side, from below near the spleen, towards the right shoulder. The anterior structures will come on the left side and all posterior strictures fall on the right side of the image.
The yellow Zone is a wide area between LAD and LCX that engulfs the whole left ventricle. The blue zone is the anteriorly placed RV, especially the RVOT, which comes closer to the left main. The one below the LCX is the posteriorly placed left atrium depicted in green zone. (Not in above picture)
Clinical Implication
As cardiologists, we literally camp inside the coronary arteries with various weaponry and ammunition. It is always wiser to know the surrounding structures, as the risk of Injury hangs like a Damocles sword . Intra-cavity perforation, though rare, can still occur, and many are not recognized because they are well tolerated. Structural interventions like LAA closure and RVOT ablations can directly pose a threat to the left main or LCX, respectively.
Final message
Getting oriented to three-dimensional coronary arterial anatomy, is indeed a tough task. Those who are able to do it, add critical value to their interventional prowess. It is good , if we try identify cardiac chambers in each coronary angiogram shots.
Reference
1.Gu G, Zhang J, Cui W. Treatment of right ventricular perforation during percutaneous coronary intervention. Cardiovasc J Afr. 2015 May 23;26(3):e4-6. doi: 10.5830/CVJA-2014-072. PMID: 26592991; PMCID: PMC4763480.
2.Nguyen-Do P, Bannon P, Leung DY. Coronary artery to the left atrial fistula after resection of atrial appendages. Ann Thorac Surg. 2004 Aug;78(2):e26-7. doi: 10.1016/j.athoracsur.2003.10.117. PMID: 15276584.
