Sleep apnea in heart failure: implications of sympathetic nervous system activation for disease progression and treatment.

Mortality risk in heart failure relates to the degree of chronic sympathetic nervous system activation. Do acute increases in central sympathetic outflow, as occur nightly in patients with sleep apnea, augment this risk? This review explores 4 novel concepts: 1) sleep disordered breathing is common in heart failure, 2) the acute effects of sleep apnea and the chronic effects of heart failure on the sympathetic nervous system are additive when these conditions coexist, 3) such convergence has adverse clinical and prognostic implications, and 4) treating sleep apnea can attenuate sympathetic nervous system activation and improve ventricular systolic function.