Anatomic characteristics of left atrium and openings of pulmonary veins

Left atrium (LA) and left atrial pulmonary venous anatomy have clinical importance for atrial fibrillation (AF) and cardiac tumor surgery. A detailed anatomic knowledge of these structures may faciliate clinical evaluations. The aim of this study was to assess LA size and to demonstrate other anatomic features of LA with pulmonary vein openings in normal population.

This descriptive laboratory study was performed in 56 hearts of adult formalin fixed cadavers. The number of pulmonary vein openings into LA was recorded. Different patterns of pulmonary vein openings were described such as common ostium and additional vein.

The roof of LA was determined as flat (75%), convex (14.3%) or concave (10.7%) in specimens. A roof pouch was present in 8.9% of specimens. The diameter of LA roof, the anteroposterior LA diameter and the LA diameter between septum and lateral wall were recorded. Thin areas on the atrial wall were observed in front of a light source around left atrial appendage orifice. Septal band was found in 7.1% of specimens. Five different patterns of pulmonary vein openings were recorded: The common arrangement, the unilateral common ostium, the unilateral additional vein, the additional vein on both side and the complex type were observed respectively in 41 specimens (73.2%), 10 specimens (17.9%), three specimens (5.4%), one specimen (1.8%) and one specimen (1.8%).

It is expected that the data from present study will be a guide to the clinicians during the surgical approaches or radiologic examinations of LA and pulmonary vein openings into LA.