Carvedilol Superior for Reducing Sympathetic Activity in HF

Background: Cardiac sympathetic innervation can be investigated with I-123 MIBG imaging, which provides prognostic information in heart failure (HF) patients. The heart:mediastinal ratio (HMR) of MIBG uptake increases as sympathetic activity increases, and a decrease in HMR over time (the washout rate) is inversely correlated with sympathetic activity. In patients with HF, sympathetic activity is increased but cardiac sympathetic innervation is downregulated in response to chronic sympathetic stimulation. Higher MIBG washout rates and lower HMRs for MIBG are poor prognostic factors in HF. There is evidence that prothrombotic activity can be modified by beta-blocker inhibition in HF patients. This effect is mediated through the β 2 -receptor. Objective: To determine whether carvedilol, a nonselective β 1 - and β 2 -receptor inhibitor, is more effective at reducing sympathetic and prothrombotic activity in HF patients than is metoprolol, a selective β 1 -receptor inhibitor. Methods: Pa more...