A mathematical model for irrigated epicardial radiofrequency ablation.

A mathematical model for epicardial radiofrequency ablation using an electrode irrigated by saline is proposed. Saline flow profiles are derived using thin film theory, and heat convection due to blood flow is also included in the model. Results from a computer implementation of the model using a finite element method suggest that transmural ablation lesions can be made in 4-mm-thick tissue. Effects of parameters such as tissue and saline layer thickness, irrigation rate, blood flow rate, and applied power are investigated. Saline is found to irrigate as well as ablate. Rise in saline temperature and consequent ablation by saline is more pronounced as saline layer becomes thicker. Electrode tip temperatures as much as 40 degrees C lower than maximum tissue temperature were found in simulations.