Parasympathetic nervous system and heart failure: pathophysiology and potential implications for therapy.

Abundant evidence links sympathetic nervous system activation to outcomes of patients with heart failure (HF).1 In contrast, parasympathetic activation has complex cardiovascular effects that are only beginning to be recognized. In particular, the pathophysiological roles of normal and disordered parasympathetic innervation in patients with HF are not understood as comprehensively.2–5 In the present article, we review cardiovascular responses to parasympathetic activation, address the modulating factors that can affect parasympathetic function, discuss the role of the vagus nerve in ventricular dysfunction, and consider how activation of the parasympathetic nervous system may have important therapeutic implications for patients with congestive HF.