Baroreflex activation for the treatment of heart failure.

Autonomic dysregulation is a feature of heart failure (HF) characterized by sustained increase of sympathetic drive and by withdrawal of parasympathetic activity. Both maladaptations are independent predictors of poor long-term outcome in patients with HF. Considerable evidence exists that supports the use of pharmacologic agents that partially inhibit sympathetic activity as an effective long-term therapy for patients with HF; the classic example being the use of selective and nonselective β-adrenergic receptor blockers. In contrast, modulation of parasympathetic activation as potential therapy for HF has received only limited attention. This review discusses the results of recent preclinical animal studies that provide support for the possible use of baroreflex electrical stimulation, also known as baroreflex activation therapy (BAT), as a long-term therapeutic approach for the treatment of patients with chronic HF. In addition to exploring the effects of chronic BAT on left ventricular (LV) function and chamber remodeling, the review will also address the effects of long-term BAT on ventricular arrhythmias and on potential modifiers of the HF state that include maladaptations of both the nitric oxide and β-adrenergic receptor signal transduction pathways. The results of the preclinical studies conducted to date have shown that in dogs with advanced HF, monotherapy with BAT improves global LV systolic and diastolic function and partially reverses LV remodeling both globally and at cellular and molecular levels. In addition, BAT therapy was shown to markedly increase the threshold for lethal ventricular arrhythmias in dogs with chronic HF. These benefits of BAT support the continued exploration of this therapeutic modality for treating patients with chronic HF and those with increased risk of sudden cardiac death.