RT Journal Article SR Electronic T1 123I-MIBG myocardial scintigraphy predicts abnormalities of myocardial functional reserve in response to β-adrenergic stimulation in idiopathic dilated cardiomyopathy patients JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1713 OP 1713 VO 51 IS supplement 2 A1 Ohshima, Satoru A1 Kobayashi, Masakazu A1 Isobe, Satoshi A1 Daisuke, Hayashi A1 Hirashiki, Akihiro A1 Bando, Yasuko A1 Izawa, Hideo A1 Abe, Shinji A1 Kato, Katsuhiko A1 Murohara, Toyoaki YR 2010 UL http://jnm.snmjournals.org/content/51/supplement_2/1713.abstract AB 1713 Objectives We examined whether 123I-MIBG myocardial scintigraphy predicts abnormalities of myocardial functional reserve in response to β-adrenergic stimulation in idiopathic dilated cardiomyopathy patients (IDCM). Methods 40 IDCM patients (NYHA class I to II, age 52±13 years, LVEF 39±11%) underwent myocardial 123I-MIBG scintigraphy and cardiac catheterization. 123I-MIBG findings were expressed as early heart-mediadtinum ratio (H/M), delayed H/M, and washout rate(WR). LV dP/dtmax and T1/2 were determined from left ventricular pressure curve during dobutamine infusion (15μg kg-1 min-1). Patients were classified as follows: group A comprised 20 patients showing a delayed H/M of ≤1.8; group B comprised 20 patients showing the ratio >1.8. Results The percent change in heart rate (%HR), LV dP/dtmax(%LV dP/dtmax) andT1/2 (%T1/2) from baseline to dobutamine stress were significantly reduced in the group A than those in group B (39±20% vs 58±24%, p<0.01; 102±46% vs 161±70%, p<0.01; 40±15% vs 50±12%, p<0.05, respectively). Significant correlations were found between delayed H/M and %HR (r=0.35, p<0.05), %LV dP/dtmax (r=0.45, p<0.01) and %T1/2(r=0.34, p<0.05). Significant correlations were also found between WR and %HR (r=0.37, p<0.05), %LV dP/dtmax(r=0.60, p<0.01) and %T1/2 (r=0.34, p<0.05). Conclusions Reduced 123I-MIBG uptake and increased washout were related to an impairment in adrenergic myocardial chronotropic (increase in HR), inotropic (increase in LV dP/dtmax), and lusitropic(shortening of T1/2) functional reserve. Myocardial 123I-MIBG scintigraphy may noninvasively predict functional reserve in response to β-adrenergic stimulation in mild to moderate IDCM patients