扩张型心肌病家兔左室壁复极异质性的改变及意义

目的：观察离体心脏左心室三层心肌的单相动作电位的改变，以探讨扩张型心肌病易发心室颤动与三层心肌跨室壁复极不均一性的关系。方法：用阿霉素制作扩张型心肌病家兔模型，测定其室颤阈值（VFT）以及心外膜、中层心肌和心内膜心肌细胞的单相动作电位复极90％时程（APD90）、跨室壁复极离散度（TDR）。结果：扩张型心肌病VFT明显降低（P＜0．001），三层心肌细胞APD90均明显延长（P＜0．001），中层心肌细胞较心外膜、心内膜下心肌细胞延长更为显著（P＜0．05）；扩张型心肌病跨室壁复极离散度增加（P＜0．01）。结论：中层心肌细胞APD90明显延长、跨室壁复极离散度增加、三层心肌复极不均一性增加可能是扩张型心肌病容易发生心室颤动的重要原因。     

Transmyocardial revascularization ameliorates ischemia by attenuating paradoxical catecholamine-induced vasoconstriction

Background  The mechanism by which transmyocardial revascularization (TMR) offers clinical benefit is controversial. We hypothesized that TMR ameliorates ischemia by reversing paradoxical catecholamine-induced vasoconstriction. Methods and Results  Chronic ischemic cardiomyopathy was created in 11 dogs by placing ameroid constrictors on the proximal coronary arteries and their major branches. Six weeks later, 35 channels were created percutaneously in the left circumflex artery region, with the left anterior descending artery region serving as control. At rest, wall thickening and myocardial blood flow did not change in the treated region, whereas they deteriorated in the control bed. Contractile and myocardial blood flow reserve increased in the treated region but deteriorated in the control region. There was diminished iodine 123 metaiodobenzylguanidine uptake and a significant reduction in noradrenergic nerves in the treated region compared with the control region, with a corresponding reduction in tissue tyrosine hydroxylase activity. Conclusions  We conclude that the absence of a catecholamine-induced reduction in MBF reserve and contractile reserve in the TMR-treated region with associated evidence of neuronal injury indicates that the relief of exercise-induced ischemia after TMR most likely results from reversal of paradoxical catecholamine-induced vasoconstriction. These findings may have implications in selecting patients who would benefit from TMR. Supported in part by grants from the National Institutes of Health (R01-HL66034 and K-08-HL074290-01). Bethesda. Md. The radio-labeled microspheres were provided by DuPont Pharmaceuticals, North Billerica. Mass, and the ultrasound equipment was supplied by Philips. Andover, Mass. Dr Leong-Poi was the recipient of a Fellowship Training Grant from the Canadian Institute of Health Research and the Heart and Stroke Foundation of Canada.     

Cardiomyopathy: a late complication of hemolytic uremic syndrome

This report describes a child who presented with classic hemolytic uremic syndrome (HUS) and 4 months later developed a life-threatening but reversible cardiomyopathy with global cardiac dysfunction and a left ventricular ejection fraction of 14%. There was no evidence of electrolyte abnormalities, anemia, hypertension, severe fluid overload, or viral infection. Endomyocardial biopsies were consistent with a dilated cardiomyopathy. This paper highlights the importance of considering the diagnosis of associated cardiomyopathy when presenting with late-onset edema following HUS. Received February 12, 1996; received in revised form and accepted August 22, 1996     

扩张型心肌病与β1 受体自身抗体关系初探

目的 探讨抗β1受体自身抗体与扩张型心肌病（DCM）之间的关系。方法 以人心脏β1受体细胞外第二环表位肽段作为抗原，应用酶联免疫吸附测定（ELISA）技术，检测28例DCM患者和32例正常人血清中β1受体的自身抗体。结果 DCM患者血清中有13例（46％）抗β1受体自身抗体阳性，正常人血清中有2例（6％），两组阳性率差异有显著性（P＜0．01）；DCM组自身抗体平均几何滴度为1：92，显著高于正常对照组1：20（P＜0．01）；DCM患者中自身抗体阳性者的抗体滴度在不同心功能间的分布差异有显著性（P＜0．001）。结论 DCM患者存在着β1受体自身抗体且其滴度也明显高于正常对照组。     

小剂量倍他乐克治疗晚期扩张性心肌病疗效及安全性观察

目的 :评价小剂量倍他乐克治疗晚期扩张性心肌病 (DCM )的疗效及安全性。方法 :2 0例晚期扩张性心肌病患者 ,经充分抗心衰治疗后 ,按入院顺序 ,随机分为A组 (倍他乐克治疗组 )和B组 (常规治疗组 ) ,比较各组治疗前后及两组间临床指标及生活质量改善情况。结果 :两组临床症状、生活质量均较入院时明显改善。A组左室射血分数(LVEF)、6分钟步行距离 (D)较B组提高 ;心率 (HR) ,心率、平均动脉压 (MBp)乘积较B组下降 ,差异有显著性 (P <0 .0 1) ;A组再住院率、住院日数较B组低 ,所有患者均能良好耐受倍他乐克 ,无心功能恶化。结论 :在充分使用血管紧张素转换酶抑制剂 (ACEI)、利尿剂和洋地黄的基础上 ,采用小剂量倍他乐克治疗晚期扩张性心肌病 ,疗效及安全性均肯定     

L-肉毒碱对阿霉素性心肌损伤保护作用的研究——心肌线粒体膜流动性测定

阿霉素可导致剂量累积性心肌细胞损伤。L-肉毒碱已确认能减轻心肌细胞形态学改变。本实验测定了心肌细胞线粒体膜流动性,目的是从生物化学角度观察L-肉毒碱对阿霉素性心肌损伤的作用。实验结果表明:阿霉素可引起线粒体膜流动性的明显改变。而补充外源肉毒碱可改善这种状态。     

~(123)I-MIBG心肌显像预测依那普利对扩张型心肌病患者治疗效果的临床价值

目的探讨123I-MIBG心肌显像在治疗前预测依那普利对扩张型心肌病(DCM)患者治疗效果的临床价值。方法对24例DCM患者于依那普利治疗前行早期(20min)及延迟(3h)123I-MIBG心肌显像,采用心/上纵隔(H/M)比和心脏放射性洗脱率(WR)作为相对半定量计数分析,与超声心功能参数进行对比。根据123I-MI-BG心肌显像延迟相的H/M分为3组延迟H/M≥1.7为组Ⅰ,1.5<延迟H/M<1.7为组Ⅱ,延迟H/M≤1.5为组Ⅲ。组Ⅰ和组Ⅱ在平均治疗4.5个月后重复以上检查。结果治疗前3组间超声心功能参数比较均无统计学差异。治疗后组Ⅰ的左室射血分数(LVEF)和左室收缩末径(LVDs)明显改善,早期H/M和延迟H/M均明显改善(P<0.05),而WR无明显变化。治疗后组Ⅱ的延迟H/M明显改善(P<0.05),而早期H/M和WR均无明显变化,心功能参数也无改善。组Ⅰ和组Ⅱ患者均能耐受依那普利治疗,而组Ⅲ患者均不能耐受依那普利治疗。结论123I-MIBG心肌显像在治疗前预测依那普利对DCM患者的治疗效果方面有一定价值。     

63例扩张型心肌病的长期随访分析

目的:评价扩张型心肌病的远期预后。方法:扩张型心肌病患者63例,给予强心、利尿、β受体阻滞剂、血管紧张素转化酶抑制剂及中药生脉(参麦)复方制剂治疗,定期随访,随访时间3～13年。随访项目包括:心功能改善情况、体力活动适应程度、院外服药治疗、再次入院次数,死亡,了解并登记死亡原因。结果:63例中随访3～5年16例,5～10年35例,10年以上12例,平均随访时间6.1年。随访期间死亡18例(病死率28.6%);存活45例,存活者患病时间2～15年,其中28例能从事一般正常劳动及工作(62.2%),生活可自理者10例(22.2%)。结论:由于治疗方案的改进,特别是中西医结合药物的应用,使扩张型心肌病患者的预后改善,平均存活时间延长,多数患者的生存质量提高。