Electrical vagus nerve stimulation for the treatment of chronic heart failure

Autonomic dysregulation is a feature of chronic heart failure (HF) and is characterized by a sustained increase of sympathetic drive and by withdrawal of parasympathetic activity. Both sympathetic overdrive and increased heart rate are predictors of poor long-term outcome in patients with HF. Pharmacologic agents that partially inhibit sympathetic activity, such as beta-adrenergic receptor blockers, effectively reduce mortality and morbidity in patients with chronic HF. In contrast, modulation of parasympathetic activation as a potential therapy for HF has received only limited attention because of its inherent complex cardiovascular effects. This review examines results of experimental animal studies that provide support for the possible use of electrical vagus nerve stimulation (VNS) as a long-term therapy for the treatment of chronic HF. The review also addresses the effects of VNS on potential modifiers of the HF state, including proinflammatory cytokines, nitric oxide elaboration, and myocardial expression of gap junction proteins. Finally, the safety, feasibility, and efficacy trends of VNS in patients with advanced HF are reviewed.