Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan.
Eur J Nucl Med Mol Imaging. 2013 Jan;40(2):262-70. doi: 10.1007/s00259-012-2256-z. Epub 2012 Oct 25.
We investigated whether myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy predicts impairment of myocardial functional reserve in response to dobutamine stress in patients with idiopathic dilated cardiomyopathy (DCM).
Forty DCM patients (LVEF 39 ± 12 %) underwent myocardial (123)I-MIBG scintigraphy, echocardiography, and cardiac catheterization. Myocardial (123)I-MIBG uptake was quantified as the delayed heart to mediastinum (H/M) ratio and washout rate (WR). Local denervation was evaluated on polar map images. LV dP/dt (max) and T(1/2) were determined from left ventricular pressure curves at baseline and during dobutamine infusion (15 μg/kg /min). Patients were classified into two groups as follows: group A comprised 21 patients showing a delayed H/M ratio of <1.9 (median value); group B comprised 19 patients showing a delayed H/M ratio of ≥ 1.9.
The percentage change in heart rate (%HR), LV dP/dt (max) (%LV dP/dt (max)), and T (1/2) (%T (1/2)) from baseline to dobutamine stress were significantly more reduced in group A than in group B (39.3 ± 20.2 %, 55.2 ± 24.1 %, p < 0.01; 102.3 ± 46.3 %, 152.0 ± 72.3 %, p < 0.05; 38.7 ± 15.3 %, 46.9 ± 15.4 %, p < 0.05, respectively). No significant differences between the two groups were observed in the echocardiographic parameters or baseline cardiac catheterization parameters. Significant correlations were found between delayed H/M ratio and %HR (r = 0.35, p < 0.05), %LV dP/dt (max) (r = 0.45, p < 0.05) and %T (1/2) (r = 0.34, p < 0.05). Significant inverse correlations were also found between WR and %HR (r = -0.37, p < 0.05), %LV dP/dt (max) (r = -0.60, p < 0.0001), and %T (1/2) (r = -0.34, p < 0.05). SPECT images revealed enhanced denervation from the inferoposterior to anterior wall in accordance with the advancement of global denervation.
Reduced (123)I-MIBG uptake and increased washout were related to impairment in adrenergic myocardial functional reserve in idiopathic DCM.
本研究旨在探讨原发性扩张型心肌病（DCM）患者心肌（123）I-间碘苄胍（（123）I-MIBG）闪烁显像能否预测多巴酚丁胺负荷试验时心肌功能储备受损的情况。
40 例 DCM 患者（LVEF 39±12%）接受心肌（123）I-MIBG 闪烁显像、超声心动图和心导管检查。通过延迟心脏与纵隔（H/M）比值和洗脱率（WR）对心肌（123）I-MIBG 摄取进行定量评估。通过极坐标图评估局部去神经支配。在多巴酚丁胺输注（15μg/kg/min）期间，从左心室压力曲线确定左心室 dp/dt（max）和 T（1/2）。根据延迟 H/M 比值将患者分为两组：A 组 21 例，H/M 比值<1.9（中位数）；B 组 19 例，H/M 比值≥1.9。
与 B 组相比，A 组的心率变化百分比（%HR）、左心室 dp/dt（max）变化百分比（%LV dP/dt（max））和 T（1/2）变化百分比（%T（1/2））显著降低（39.3±20.2%、55.2±24.1%，p<0.01；102.3±46.3%、152.0±72.3%，p<0.05；38.7±15.3%、46.9±15.4%，p<0.05）。两组之间的超声心动图参数或基线心导管检查参数无显著差异。延迟 H/M 比值与%HR（r=0.35，p<0.05）、%LV dP/dt（max）（r=0.45，p<0.05）和%T（1/2）（r=0.34，p<0.05）呈显著相关性。WR 与%HR（r=-0.37，p<0.05）、%LV dP/dt（max）（r=-0.60，p<0.0001）和%T（1/2）（r=-0.34，p<0.05）呈显著负相关。SPECT 图像显示，随着整体去神经支配程度的加重，从前壁到后壁的神经支配增强。
原发性 DCM 患者心肌（123）I-MIBG 摄取减少和洗脱增加与儿茶酚胺能心肌功能储备受损有关。
