Aims: Our objective was to study the anatomic relations of the human left atrial oblique vein (Marshall vein), particularly of its ostium opening into the coronary sinus, in order to guide ablation procedures related to that vein.
Methods and results: The study was carried out in 23 heart-specimens (mean weight 446 +/- 204 g) of individuals whose mean ages were 43 +/- 21 years, 20 males. The coronary sinus was opened longitudinally, exposing the ostium of the tributary veins; the Vieussens valve was looked for, as well as its relationship to the left atrial oblique vein. The diameters of the left atrial oblique vein and the coronary sinus ostia were measured and the distance between them was determined. The left atrial oblique vein could be identified in 20 (87%) of the hearts, while the Vieussens valve was present in 17 (74%) of the specimens (in 16 of which the left atrial oblique vein was identified). In such condition, the vein was adjacent to the Vieussens valve and proximally positioned relative to the coronary sinus ostium in most of them (14/16 cases). The mean diameters of the left atrial oblique vein and of the coronary sinus ostia were, respectively, 1.23 +/- 0.38 and 8.22 +/- 1.88 mm. The mean distance between both ostia was 30.9 +/- 10.2 mm.
Conclusion: When present, the left atrial oblique vein can be easily recognized, adjacent to the Vieussens valve. The mean distance between the coronary sinus opening and left atrial oblique vein ostium was around 30 mm, independently of the heart weight and the presence of cardiomegaly.