In vivo measurements of heat transfer on the endocardial surface.

A catheter-based instrument was used to measure the heat transfer on the right atrial and ventricular endocardial surfaces of two pigs in vivo. The heat transfer parameters will assist in calculating the proper dose for radio-frequency ablation. The time constant of the device was 0.05 s. It was found that the average heat convection coefficient varies significantly both spatially and temporally on the endocardium. The average heat convection coefficients found were between 510 and 4800 W m(-2) K(-1).