Congestive Heart Failure

The sympathetic nervous system (SNS) component of the autonomic nervous system (ANS) has been studied extensively in patients with congestive heart failure (CHF). Modern therapy for heart failure has been revolutionized by the use of agents that block some of the effects of the SNS. In CHF, increased plasma levels of norepinephrine (NE) and the increased urinary excretion of catecholamines indicate heightened activation of the SNS. This activation of SNS occurs early in the course of the disease as shown in the Studies of Left Ventricular Dysfunction (SOLVD) trial. SOLVD has demonstrated that NE is significantly greater in asymptomatic patients with impaired left ventricular (LV) function than in control subjects. The magnitude of SNS activation is closely linked with prognosis in CHF. Individuals with high levels of SNS activation, as estimated by plasma NE values, have the worst prognosis.