Effects of candesartan on cardiac sympathetic nerve activity in patients with congestive heart failure and preserved left ventricular ejection fraction

Abstract

We sought to evaluate the effects of angiotensin receptor blocker (ARB) on cardiac sympathetic nerve activity (CSNA) in patients with congestive heart failure (CHF) with a preserved left ventricular ejection fraction (LVEF). Approximately 50% of patients with CHF have preserved LVEF. It is reported that ARB therapy improves CSNA in CHF patients and reduced LVEF. However, the effect of ARB therapy on CSNA evaluated by iodine-123 meta-iodobenzylguanidine ((123)I-MIBG) scintigraphy has not been determined in CHF patients with preserved LVEF. We selected 50 patients with nonischemic CHF and LVEF >40% who were treated with standard therapy. Twenty-five patients were randomized to also receive candesartan, whereas the remaining 25 patients received placebo. The delayed heart/mediastinum count (H/M) ratio, delayed total defect score (TDS), and washout rate (WR) were determined by (123)I-MIBG scintigraphy before and six months after treatment. The LV end-diastolic volume and LVEF were determined by echocardiography, and the plasma brain natriuretic peptide (BNP) concentration was also measured. In patients receiving candesartan, (123)I-MIBG scintigraphic and echocardiographic parameters were significantly improved after treatment. In contrast, there were no significant changes in these parameters in patients receiving placebo. There was a significant correlation between the changes in (123)I-MIBG scintigraphic findings and the percent change in BNP from baseline to six months in patients receiving candesartan (TDS: r = 0.587, p < 0.005; H/M ratio: r = -0.509, p < 0.01; WR: r = 0.602, p < 0.005). Adding candesartan to standard therapy can improve CSNA and LV performance in CHF patients with preserved LVEF.