Cardiac arrhythmias, a condition in which the heart beats irregularly, are typically treated with drug or cardiac ablation therapy. More recently, external beam ablation therapy has been proposed as a potential approach for treating cardiac arrhythmias. Currently, a significant challenge regarding external beam ablation therapy in the heart is compensation for cardiac motion to ensure precise targeting. Porcine animal models are often used for evaluating image-guided intervention systems for cardiac applications; however, to date there have been relatively few studies evaluating motion in the swine heart. In this study, we model and quantify cardiac motion in the left atrium and left ventricle of three beating porcine hearts by tracking anatomic landmarks across twenty phases of the cardiac cycle from multi-phase computed tomography images. 10 landmarks are tracked for each porcine heart, 5 in the left atrium and 5 in the left ventricle. The mean (std) displacement for the 5 left atrial landmarks is 5.5(3.5) mm in x, 5.0(2.9) mm in y, and 5.6(3.3) mm in z. The mean (std) displacement for the 5 left ventricular landmarks is 7.1(3.8) mm in x, 9.9(5.2) mm in y, and 7.7(3.1) mm in z.