Kobayashi Masakazu, Izawa Hideo, Cheng Xian Wu, Asano Hiroyuki, Hirashiki Akihiro, Unno Kazumasa, Ohshima Satoru, Yamada Takashi, Murase Yosuke, Kato Tomoko S, Obata Koji, Noda Akiko, Nishizawa Takao, Isobe Satoshi, Nagata Kohzo, Matsubara Tatsuaki, Murohara Toyoaki, Yokota Mitsuhiro
Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
JACC Cardiovasc Imaging. 2008 Nov;1(6):718-26. doi: 10.1016/j.jcmg.2008.04.012.
We performed dobutamine stress testing for evaluation of myocardial contractile reserve in asymptomatic or mildly symptomatic patients with dilated cardiomyopathy (DCM).
Catecholamine sensitivity is reduced in failing hearts as a result of myocardial abnormalities in the beta-adrenergic receptor signaling pathway. However, little is known about adrenergic myocardial contractile reserve in asymptomatic or mildly symptomatic patients with DCM.
The maximal first derivative of left ventricular pressure (LV dP/dt(max)) was determined during infusion of dobutamine (10 microg kg(-1) min(-1)) in 46 asymptomatic or mildly symptomatic (New York Heart Association functional class I or II) patients with DCM. The expression of messenger ribonucleic acid (mRNA) for contractile regulatory proteins in endomyocardial biopsy specimens was quantified by reverse transcription and real-time polymerase chain reaction analysis. Plasma norepinephrine levels were measured in all patients and [(123)I]metaiodobenzylguanidine (MIBG) scintigraphy performed.
Patients were classified into 3 groups based on the percentage increase in LV dP/dt(max) induced by dobutamine (DeltaLV dP/dt(max)) and on LV ejection fraction (LVEF) at baseline: group I (n = 18): DeltaLV dP/dt(max) >100% and LVEF >25%; group IIa (n = 17): DeltaLV dP/dt(max) <or=100% and LVEF > 25%; and group IIb (n = 11): DeltaLV dP/dt(max) <or=100% and LVEF <or=25%. The amounts of beta(1)-adrenergic receptor, sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase, and phospholamban mRNA were significantly smaller in groups IIa and IIb than in group I. The plasma norepinephrine level was increased and the delayed heart/mediastinum count ratio in MIBG scintigraphy was decreased in both groups IIa and IIb.
Dobutamine stress testing is a useful diagnostic tool for identifying reduced adrenergic myocardial contractile reserve related to altered myocardial expression of beta(1)-adrenergic receptor, sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase, and phospholamban genes even in asymptomatic or mildly symptomatic patients with DCM.
我们对无症状或症状轻微的扩张型心肌病（DCM）患者进行了多巴酚丁胺负荷试验，以评估心肌收缩储备功能。
由于β-肾上腺素能受体信号通路中的心肌异常，衰竭心脏的儿茶酚胺敏感性降低。然而，对于无症状或症状轻微的DCM患者的肾上腺素能心肌收缩储备功能知之甚少。
对46例无症状或症状轻微（纽约心脏协会心功能I级或II级）的DCM患者在输注多巴酚丁胺（10μg·kg⁻¹·min⁻¹）期间测定左心室压力的最大一阶导数（LV dP/dt(max)）。通过逆转录和实时聚合酶链反应分析对心内膜活检标本中收缩调节蛋白的信使核糖核酸（mRNA）表达进行定量。测定所有患者的血浆去甲肾上腺素水平并进行[¹²³I]间碘苄胍（MIBG）闪烁显像。
根据多巴酚丁胺诱导的LV dP/dt(max)增加百分比（ΔLV dP/dt(max)）和基线时的左心室射血分数（LVEF），将患者分为3组：I组（n = 18）：ΔLV dP/dt(max)>100%且LVEF>25%；IIa组（n = 17）：ΔLV dP/dt(max)≤100%且LVEF>25%；IIb组（n = 11）：ΔLV dP/dt(max)≤100%且LVEF≤25%。IIa组和IIb组中β₁-肾上腺素能受体、肌浆网Ca²⁺-三磷酸腺苷酶和受磷蛋白mRNA的量明显低于I组。IIa组和IIb组的血浆去甲肾上腺素水平均升高，且MIBG闪烁显像中的延迟心脏/纵隔计数比值降低。
多巴酚丁胺负荷试验是一种有用的诊断工具，即使在无症状或症状轻微的DCM患者中，也可用于识别与β₁-肾上腺素能受体、肌浆网Ca²⁺-三磷酸腺苷酶和受磷蛋白基因心肌表达改变相关的肾上腺素能心肌收缩储备功能降低。
