Evaluation of heating method for the pacemaker determination.

This paper describes certain changes in the heart frequency, which are produced by localized heating of various parts of the sinus venosus. It was formerly found by Gaskell (1) that the heating of the sinus venosus causes an acceleration while heating of atria and ventricle had no remarkable effect on heart rate. In this phenomenon, however, there are still some problems to be solved. One unsettled question is, whether the whole sinus venosus must be warmed or whether it is sufficient to warm only a particular part of the sinus in order to cause tachycardia. The experiments to be reported were carried out in an attempt to answer this question by using a small thermode.