Abnormal Baroreflex Mechanisms in Congestive Heart Failure

P atients with low output congestive heart failure have less-than-normal slowing of heart rate during pharmacologic increases of arterial pressure, indicating impairment of the arterial baroreceptor-heart rate reflex.1 The mechanism underlying this abnormality is not fully understood and could involve one or more components of the reflex arc, including an afferent limb (generation and transmission of baroreceptor neural impulses), central neural processing of afferent neural impulses (most importantly in the nucleus tractus solitarius), and an efferent limb that includes transmission of neural impulses in efferent pathways and end-organ responses to these efferent impulses. In this issue of Circulation, Wang et a12 present results from studies