Author + information
- Vladimer Bakhutashvili1,
- Alexander J. Hill2,
- Rajiv Gupta3,
- Srinivasan Varahoor4,
- John Karanian1 and
- William F. Pritchard1
Emerging endovascular ablation therapies for the treatment of atrial fibrillation are evaluated in animal models prior to approval for use in humans; however, pertinent anatomy of the left atrium and pulmonary vein ostia is not well defined in the literature. The anatomy of the left atrium and pulmonary vein ostia in swine and sheep were compared to homologous structures in the human.
Three dimensional models of the pulmonary veins and left atria were created from CT angiogram datasets of eight sheep and swine, and four normal humans (Mimics, Materialise, Leuven, Belgium). Centerlines were generated for the pulmonary veins and subsequent measurements included ostial cross sectional area and eccentricity, ostial projection angles, atrial volumes and atrial diameters. Each parameter was measured and compared at end systole and end diastole (Figure 1A).
In sheep and swine, the left pulmonary veins enter the atrium posteriorly as opposed to laterally as in the human and were larger (p<0.001) in cross sectional area than human ostia. The human left atrium was larger (mean volume in end systole 98±23 ml, p<0.05) in comparison to the sheep and swine (71±11 ml and 77±8 ml, respectively). The left atrial appendage was significantly larger (p<0.001) and constituted a larger percentage of the left atrial volume in the animals (sheep 33%, swine 46%) in comparison to the human (6%) (Figure 1B,C,D).
In terms of cross sectional area and shape, the swine right pulmonary vein is closest to the human pulmonary vein anatomy. However, both the orientation and morphology of the sheep and swine left atria and pulmonary veins is significantly different from that of the human. One should consider these comparative differences when developing ablative therapies and evaluating their delivery and deployment in preclinical models.