799-6 I-123 Metaiodobenzylguanidine Scintigraphy for the Prediction of Response to Beta Blocker Treatment in Patients with Dilated Cardiomyopathy

Beta blocker (B) therapy is effective for some patients (pts) with DCM. Also, it has been suggested that l-123 Metaiodobenzylguanidine (MIBG) myocardial imaging is useful to evaluate the severity of dilated cardiomyopathy (DCM). However, there are no data which patients in DCM are effectual to B therapy. This study was performed to evaluate whether MIBG can predict the response to B therapy in pts with DCM. Therefore, MIBG imaging was performed in 19 pts with DCM (M: 12, F: 7, age 13 to 68) before the start of B (bisoprolol). The heart to mediastinum MIBG uptake ratio (H/M) was detected in initial (INIT: 30 min) and delayed (DEL: 4 hr) images and the percent washout (WR) of MIBG from myocardium was obtained from them. Left ventricular fractional shortening (LVFS) was measured with echocardiography. In 19 pts, 12 had good response to B therapy, but 7 failed in this therapy because of advanced heart failure.Results are shown below (Data are shown by Mn±SD).respondednot respondedNo of pts127NYHA class III92class IV35LVFS14±410±4(p<0.05)H/M INIT2.45±0.601.78±0.48(p<0.05)DEL2.28±0.59141±0.29(p<0.01)WR37±11%47±12%(NS)ConclusionThese results demonstrated that MIBG H/M ratio (>1.7: mean-SD in responded pts) in DEL images is a better marker to find out pts responded to B therapy in DCM, than WR or NYHA class