Cardiopulmonary baroreflex control of renal sympathetic nerve activity is impaired in dogs with left ventricular dysfunction.

•The mechanisms of sympathetic and neurohormonal excitation in HF remain incompletely understood.•We tested cardiopulmonary baroreflex control of sympathetic activity using an animal model of LV dysfunction in the absence of HF and the relationship of abnormalities in baroreflexes to the development of the neurohumoral excitatory state.•Cardiopulmonary baroreflex control of sympathetic activity was progressively attenuated with moderate and severe degrees of LV dysfunction.•Arterial baroreflex control of sympathetic activity was preserved at all stages of LV dysfunction.•Plasma norepinephrine, renin activity, and arginine vasopressin remained unchanged at these stages of LV dysfunction.•Abnormalities in cardiopulmonary baroreflexes occur early in the development of LV dysfunction and could contribute to subsequent neurohumoral excitation in HF.