TY - JOUR T1 - Recovery of the Cardiac Adrenergic Nervous System After Long-Term β-Blocker Therapy in Idiopathic Dilated Cardiomyopathy: Assessment by Increase in Myocardial <sup>123</sup>I-Metaiodobenzylguanidine Uptake JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 49 LP - 54 VL - 42 IS - 1 AU - Ulrich Lotze AU - Stefan Kaepplinger AU - Andreas Kober AU - Barbara M. Richartz AU - Dietmar Gottschild AU - Hans R. Figulla Y1 - 2001/01/01 UR - http://jnm.snmjournals.org/content/42/1/49.abstract N2 - In chronic heart failure, elevated plasma norepinephrine (NE) levels and a disparity between the neuronal release and the effective reuptake of NE lead to an increased concentration of NE in the presynaptic cleft, causing a downregulation of the myocardial β-adrenoceptors. The clinical and prognostic effectiveness of β-blocker therapy has been shown in patients with chronic heart failure in several large trials. The purpose of this study was to investigate the effect of long-term β-blocker therapy on the cardiac adrenergic nervous system as assessed by the myocardial uptake of 123I-metaiodobenzylguanidine (MIBG), an analog of NE, in idiopathic dilated cardiomyopathy (IDC). Methods: In 10 patients with IDC and stable chronic heart failure the myocardial MIBG uptake was measured at baseline and at 1 y (median, 11.5 mo) after treatment with β-blockers (metoprolol, n = 5; bisoprolol, n = 1; and carvedilol, n = 4) in addition to standard medication. In parallel with the changes in MIBG uptake, the New York Heart Association functional class, the left ventricular ejection fraction (LVEF), and the left ventricular end-diastolic diameter (LVEDD) were documented before and after 1 y of therapy with β-blockers. Results: During the 1-y follow-up, a significant increase in myocardial 123I-MIBG uptake (P = 0.005) in parallel with an improved LVEF (P = 0.005) and a reduced LVEDD (P = 0.019) was found. A trend toward an improvement of the New York Heart Association functional class under the β-blocker therapy (P = 0.139) was also found. Conclusion: Assessment of the myocardial 123I-MIBG uptake is a useful noninvasive tool for evaluating changes in cardiac sympathetic nerve activity under medical therapy. Long-term treatment with β-blockers in IDC causes a recovery of the cardiac adrenergic nervous system concomitantly with a clinical and hemodynamic improvement. ER -