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Updated: Jul 15, 2026
Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Published on: February 26, 2013
Occluding the left atrial appendage: anatomical considerations
1National Heart and Lung Institute, Imperial College, Guy Scadding Building, Dovehouse Street, London SW3 6LY, UK.
Insights
Left atrial appendage (LAA) occlusion can reduce stroke risk in atrial fibrillation. This study details LAA anatomy and proximity to critical structures, identifying potential risks during procedures.
Area of Science:
- Cardiovascular Anatomy
- Interventional Cardiology
- Cardiac Surgery
Background:
- Left atrial appendage (LAA) occlusion is a strategy to prevent thromboembolic events in atrial fibrillation patients.
- Understanding LAA anatomy is crucial for safe and effective procedural interventions.
Purpose of the Study:
- To anatomically characterize the LAA and its relationship with adjacent structures.
- To identify potential risks to neighboring anatomy during LAA occlusion procedures.
Main Methods:
- Gross examination of 31 human heart specimens.
- Histological analysis of four LAA samples.
- Endocast creation for 11 LAA specimens.
- Measurement of LAA orifice dimensions and proximity to pulmonary veins, mitral valve, and coronary arteries.
Main Results:
- The LAA orifice is typically oval, with a mean diameter of 17.4 mm.
- The LAA orifice is closely situated to the left superior pulmonary vein (mean 11.1 mm) and mitral valve (mean 10.7 mm).
- The left anterior descending artery, circumflex artery, and sinus node artery are in proximity; thin atrial walls and crevices are common near the LAA os.
Conclusions:
- The LAA orifice anatomy presents potential risks to the left superior pulmonary vein, mitral valve, and left anterior descending coronary artery during occlusion procedures.
- Common findings of thin atrial walls and crevices near the LAA necessitate careful consideration during interventions.
Background:
Occlusion of the left atrial appendage (LAA) is thought to reduce the risk of thromboembolic events in patients with atrial fibrillation.
Objective:
To examine the LAA and its relationship to neighbouring structures that may be put at risk when intervening to occlude its os.
Methods:
31 heart specimens were examined grossly. Four of the LAAs were processed for histological examination and endocasts were made from 11 appendages. The diameters of the LAA os and proximity to the left superior pulmonary vein, mitral valve and left anterior descending artery were measured and areas of thin atrial wall in the vicinity were noted.
Results:
The LAA orifice was oval shaped in all cases with a mean (SD) diameter of 17.4 (4) mm (range 10-24.1). The mean (SD) distances of the LAA orifice to the left superior pulmonary vein and mitral valve were 11.1 (4.1) mm and 10.7 (2.4) mm, respectively. The left anterior descending, circumflex artery and, in 6 cases, the sinus node artery, were in close proximity to the LAA. Pits or troughs and areas of thin atrial wall were found in 57.7% of hearts within a 20.9 mm radius from the os. Histology showed small crevices and areas of very thin wall within the trabeculated appendage.
Conclusions:
The LAA orifice is oval shaped and thin areas of appendage wall and atrial wall are common. Potentially, the left superior pulmonary vein, mitral valve and anterior descending coronary artery can be at risk during occlusion of the os.
