SYMPATHETIC ACTIVATION IN CONGESTIVE HEART FAILURE AND ITS CORRELATES

Abstract

Objective: Microneurographic recording of sympathetic nerve traffic (MSNA) has shown that sympathetic activation occurs in heart failure (HF). However, the small sample size of the available studies, the presence of comorbidities and confounders and the heterogeneity of the patients do not allow to draw definitive conclusions particularly in mild severity CHF. The present metanalysis evaluated 2530 CHF patients of different clinical severity recruited in 106 microneurographic studies. Design and method: Assessment was extended to the relationships of MSNA with other neuroadrenergic markers, such as venous plasma norepineprhine (NE) and heart rate (HR) and echocardiographic parameters (left ventricular end-diastolic diameter - LVEDD- and left ventricular ejection fraction -LVEF). Results: MSNA was significantly greater (1.9 times, p < 0.001) in CHF patients as compared to healthy controls, a progressive significant increase being observed from NYHA class I to IV in unadjusted and adjusted analyses. MSNA was significantly greater in both untreated and treated CHF (p < 0.001 for both), related to LVEDD and to a lesser extent to LVEF (r = 0.24 and r = 0.05, p < 0.001 and p < 0.01 respectively) and closely associated with HR (r = 0.66, p < 0.001) and venous plasma norepineprhine (r = 0.68, p < 0.001). Conclusions: CHF patients are characterized by sympathetic overactivity which mirrors the degree of the impairment of the left ventricular dilatation and the severity of CHF independently of the initial or later stage of the CHF condition, its etiology and the presence of pharmacological treatment. Venous plasma NE and HR represent potentially useful markers of sympathetic activation in the clinical setting.