Laryngeal aortic baroreceptor pathways and cardiac arrhythmia.

This study was undertaken to confirm the effect of the ramus communicans baroreceptor pathway on cardiac rate during an upper-respiratory tract disturbance. The effects of destruction of this pathway were tested. It was found that cardiac rate could still be altered by stimulation of the main trunk of the superior laryngeal nerve, although the ramus communicans fibers were absent. Electrical stimulation of only the main trunk of the superior laryngeal nerve, but not any of its branches, is capable of causing cardiac changes. Cardiac changes also occur readily with mechanical stimulation of the area immediately superior to the vocal folds, despite bilateral destruction of the recurrent and superior laryngeal nerves. These findings question the proposed role of the laryngeal baroreceptor pathway as a major factor in the cause of cardiac changes related to intubation.