This editorial refers to ‘Chronic vagal stimulation for the treatment of low ejection fraction heart failure: results of the Neural Cardiac TherApy foR Heart Failure (NECTAR-HF) randomized controlled trial’, by F. Zannad et al., on page doi:10.1093/eurheartj/ehu345
It has been estimated that the prevalence of heart failure with a reduced ejection fraction exceeds 20 million patients worldwide—about 2% of the general population in the Western world—and that the annual incidence is >2 million patients per year.1 The mortality of heart failure exceeds that of many malignancies. Significant healthcare improvements have been made with regard to pharmaceutical therapy, cardioverter defibrillator implantation, and biventricular pacing, but the risk of mortality remains high, and many patients remain very symptomatic, as evidenced by frequent hospitalizations, reduced exercise tolerance, and degraded quality of life.
Patients with congestive heart failure have a major disturbance of autonomic function: heightened sympathetic and reduced parasympathetic activity. Induced heart failure leads to this imbalance2 and, in turn, the imbalance leads to aggravation of heart failure.3 The overactive sympathetic system can be addressed by treatment with beta-adrenergic blockade or inhibitors of the renin–angiotensin–aldosterone system, and reduced parasympathetic activity can be bolstered to some extent by physical training and low dose digoxin.
Several relatively new and experimental non-pharmacological interventions which target specific aspects of autonomic imbalance (e.g. renal denervation, cardiac contractility modulation, spinal cord stimulation, and carotid sinus nerve stimulation)4 are being actively investigated.
It is also possible to stimulate the vagus nerve directly to improve parasympathetic tone and reflexes. It has been shown that vagal nerve stimulation (VNS) leads to improved left ventricular …