Sympathetic nervous system in heart failure.

For those who have comfortably accepted the mechanistic link between sympathetic nervous system activation and poor outcome in heart failure, the study by Brede et al1 in this issue of Circulation is a welcome confirmation. The authors appear to have demonstrated in a murine model that absence of sympathoinhibitory 2 adrenoreceptors is associated with overactive catecholamine release, aggressive remodeling of the left ventricle, worsening signs of heart failure, and shortened life expectancy. Provocatively, deletion polymorphism of the 2 receptor in patients with heart failure also appears to be associated with worse heart failure and poorer outcome.