Effect of increased pressure within a right heart cul-de-sac on heart rate in dogs

Abstract

Increases in heart rate consistently were elicited by moderate increases in pressure within a right heart cul-de-sac of a modified canine right heart bypass preparation. Higher elevations in cul-de-sac pressure caused slowing of the heart rate. Similar results were obtained after cervical vagotomy and sympathetic blockade. This study is interpreted as giving evidence against the existence of any cardiac accelerator or decelerator reflexes elicited by changes in right heart pressure. The alterations in heart rate appear to be produced by local mechanisms within the heart.