Luminal esophageal temperature monitoring is of high importance during catheter ablation surgeries of the left atrium. A device is currently under development to accurately measure temperature of the inner esophageal wall. Ex vivo tests using porcine esophageal and left atrial tissue have been set up and performed to better understand heat flow through the biomaterials in contact. To compliment ex vivo experiments, a numerical analysis using thermal finite element analysis has been implemented to compliment ex vivo experiments with a numerical study of the temperature distribution across tissue layers as a function of tissue thickness, as well as heat source contact size and time. Both the ex vivo experiments and finite element simulations aid in development of a practical prototyped device for potential use during catheter ablations.