Influence of Temperature on S-A Rate of Dog's Heart in Denervated Heart-Lung Preparation

Abstract

The temp, of S-A nodal tissue was recorded with a needle thermocouple in Starling''s heart-lung prepn. in which the blood was cooled and rewarmed. Within the range of 25 to 38[degree]C the relationship between S-A temp. and auricular rate was linear with an increase of 8.3 beats/min./degree rise of temp. (avg. of 5 expts.). At 25[degree]C the rate was approx. 50/min. below which heart stopped and above 38[degree]C the relationship was not linear. The nonlinear curves of other investigators are discussed and the importance of taking into account the range of temp. is emphasized.