Myocardial oxygenation at high workstates in hearts with left ventricular hypertrophy
Myocardial oxygenation at high workstates in hearts with left ventricular hypertrophy
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DOI：
10.1016/s0008-6363(98)00332-0
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发表时间：
1999-06-01
影响因子：
10.8
通讯作者：
Ugurbil, K
中科院分区：
文献类型：
--
作者：
Bache, RJ;Zhang, JY;Ugurbil, K
背景资料：由于输入儿茶酚胺而产生的高心脏负荷导致心肌磷酸肌酸（PCr）的损失和无机磷酸盐（Pi）的积累，这在左心室肥厚（LVH）的心脏中比在正常心脏中更突出。由于缺血可引起与儿茶酚胺刺激期间类似的磷酸化化合物的变化，因此本研究验证了以下假设：LVH中高负荷期间PCr的过度消耗和Pi的累积是肌细胞氧合受损的结果。方法与结果：用P-31-和H-1-NMR光谱分别测定8只正常犬和9只升主动脉缩窄所致左室肥厚犬心肌高能磷酸盐水平和肌红蛋白去饱和度。LVH组的平均LV重量/体重比约为正常值的两倍。多巴酚丁胺输注（15和30 μ g/kg/min）和多巴酚丁胺+多巴胺（每次20 μ g/kg/min）引起心率与左室收缩压乘积的进行性相似增加，正常动物最大为57.4 ± 3.3.10（3），左室肥厚动物最大为63.9 ± 2.7.10（3），而心肌耗氧量在正常人中从0.09 ± 0.01增加到0.24 ± 0.04，在LVH中从0.10 ± 0.02增加到0.25 ± 0.03ml/min/g。在基础状态下，LVH心脏的PCr/ATP比值（心外膜下、中壁和内膜下分别为1.73+/-0.10，1.61 +/-0.09和1.51+/-0.09）低于正常心脏（2.24+/-0.09，2.01 +/-0.08和1.89+/-0.07;各P
Background: High cardiac workloads produced by catecholamine infusion result in loss of myocardial phosphocreatine (PCr) and accumulation of inorganic phosphate (Pi) which are more prominent in hearts with left ventricular hypertrophy (LVH) than in normal hearts. Since ischemia can cause changes in phosphorylated compounds similar to those during catecholamine stimulation, this study tested the hypothesis that the exaggerated depletion of PCr and accumulation of Pi during high workloads in LVH is the result of impaired myocyte oxygenation. Methods and results: P-31- and H-1-NMR spectroscopy were used to determine myocardial high energy phosphate levels and myoglobin desaturation, respectively, in eight normal dogs and nine dogs with LVH produced by ascending aortic banding. The mean LV weight/body weight ratio was approximately twice normal in the LVH group. Infusion of dobutamine (15 and 30 mu g/kg/min), and dobutamine+dopamine (each 20 mu g/kg/min) caused progressive similar increases in the heart rateXsystolic LV pressure product to a maximum of 57.4+/-3.3.10(3) in normal and 63.9+/-2.7.10(3) in LVH animals, while myocardial oxygen consumption increased from 0.09+/-0.01 to 0.24+/-0.04 in normals and from 0.10+/-0.02 to 0.25+/-0.03 ml/min/g in LVH. PCr/ATP ratios during basal conditions were lower in LVH hearts (1.73+/-0.10, 1.61+/-0.09 and 1.51+/-0.09 in subepicardium, midwall and subendocardium, respectively) as compared with normals (2.24+/-0.09, 2.01+/-0.08 and 1.89+/-0.07; each p