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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
目的:观察缺氧及停止缺氧后对大鼠心肌血流量的影响。方法:34只Wistar大鼠,随机分为4组:①平原对照组;②急性缺氧组;③慢性缺氧组;④返回平原组。以放射性生物微球法测定心肌血流量。结果:急性缺氧引起PaO2、心输出量及氧运送量降低,但左、右心室心肌血流量明显增加;慢性缺氧时右心室收缩压、血球压积、血液粘滞性及右心室生理指数明显增加,而心肌血流量接近正常。停止缺氧30d后,上述所有指标均与平原以 相似文献
82.
Myocardial cooling and right ventricular function in patients with right coronary artery disease: antegrade vs. retrograde cardioplegia 总被引:1,自引:0,他引:1
E. L. HONKONEN L. KAUKINEN E. J. PEHKONEN S. KAUKINEN 《Acta anaesthesiologica Scandinavica》1997,41(2):287-296
Background: Protection of the right ventricular (RV) myocardium during ischaemia in cardiac surgery is difficult, especially in patients with severe right coronary artery (RCA) disease. Retrograde coronary sinus cardioplegia is thought to distribute uniformly, but doubts still remain as to its adequacy in RV preservation. This study evaluated distribution of antegrade vs. exclusively retrograde coronary sinus cold blood cardioplegia by assessing myocardial cooling and compared the effects on RV function. Methods: Fifty-eight patients scheduled for elective coronary artery surgery - 29 patients with significant RCA disease and another 29 with no significant RCA stenosis (controls) - were randomised to receive either antegrade or retrograde cold blood cardioplegia through either aortic root or conventional self-inflating coronary sinus catheter (RCA-ante, RCA-retro, C-ante and C-retro groups). RV function was assessed by fast-response thermodilution. Myocardial temperatures were measured in the anterior and posterior wall of the right and left ventricle. Results: Cooling of the posterior wall of the RV was effective only in the control patients given antegrade cardioplegia (14.7°C), whereas in the other groups the lowest myocardial temperatures there remained above 20°C (RO.001). In patients with obstructed RCA both antegrade and retrograde cold cardioplegia led to uneven cooling of the myocardium. After cardiopulmonary bypass the RV ejection fraction (RVEF), RV stroke work index (RVSWI) and cardiac index (CI) were significantly reduced in the RCA-retro group, and RVSWI and CI in the C-retro group, too. Regression analysis showed an inverse relationship between the temperatures of the posterior walls of the ventricles and changes in the RVEF and CI. Conclusions: Retrograde and antegrade cardioplegia alone were not effective in reducing the temperature of the posterior wall of the RV in the patients with obstructed RCA, in whom with retrograde cardioplegia RV haemodynamics were impaired for 1 hour following bypass. Neither retrograde nor antegrade cardioplegia alone can be relied on to protect the posterior wall of the RV in the patients with obstructed RCA. 相似文献
83.
Prof. Dr. W. Bernauer 《Basic research in cardiology》1991,86(1):1-10
Summary In isolated perfused rat hearts global ischemia for 2, 5, and 15 min was produced. Depending on the duration of the ischemia, postischemic reperfusion led to the release of adenosine and its catabolites, and to more or less severe ventricular tachyarrhythmias. When ventricular fibrillation occurred, a highly significant increase in the purine release was observed compared with non-fibrillating hearts. Prevention of fibrillation by antiarrhythmic drugs decreased the purine release in a highly significant way. After only 2 min of ischemia, reperfusion did not lead to ventricular fibrillation. Electrical induction of fibrillation during the reperfusion in these hearts provoked the release of very high amounts of the purine compounds. A similar effect of electrically-induced fibrillation was also obtained in hearts without a previous ischemic period. The findings suggest that ventricular fibrillation is able to induce the release of purine derivatives from the heart. 相似文献
84.
高血压患者左室舒张功能与左室肥厚的关系及随龄改变 总被引:1,自引:0,他引:1
为探讨原发性高血压 (以下简称高血压 )患者的左室舒张功能和左室肥厚的关系及其随龄改变 ,抽取 1995年 2月至 2 0 0 2年 7月间门诊高血压患者 4 81例为高血压组 ,以同期体检健康者 2 54 3例为对照组 ,年龄 10~ 80岁 ,并将原发性高血压患者分为 3级 ,每级中按性别分 2组。采用惠普 2 50 0彩色多普勒超声诊断系统检测 2组的室间隔厚度、左室后壁厚度、E/A等指标。使用SPSS软件进行统计学处理分析。结果 :高血压和正常对照组相比E/A显著下降 ,室间隔和左室后壁显著增厚 (P <0 .0 1)。 2个组的E/A均随年龄下降 ,而室间隔厚度随年龄增厚 ,且室间隔厚度和E/A呈显著负偏相关 (P <0 .0 1)。在高血压分级组中 ,Ⅰ~Ⅲ级高血压组中男性的室间隔厚度均厚于女性 (均P <0 .0 1) ,Ⅰ、Ⅱ级高血压组中男性的左室后壁厚度厚于女性 (P <0 .0 5,P <0 .0 1) ,Ⅰ级高血压组中女性的E/A低于男性 (P <0 .0 5)。提示 :左室舒张功能随着年龄的增加而降低 ,而且和高血压左室肥厚呈负偏相关关系 ,性别对其也有一定的影响 相似文献
85.
The Effects of Na~+/Ca~(2+) exchange (NCX) on the Repolarization of Canine Ventricular Myocyte-Potential Arrhythmogenic Effect of NCX during a Mis-matched Repolarization and Relaxation Xiamen Zhongshan Hospital, Xiamen Medical College, Xiamen University@巩燕$Visiting scholar of cardiac arrhythmia research institute,university hospital of Oklahoma!U.S.A
@王焱
@BELA Szabo$Basic cardiac research laboratory,cardiac arrhythmia research institute,university hospital of Oklahoma!… 相似文献
86.
目的 :探讨右室心内膜永久性起搏电极植入术中 ,心尖部起搏与流入道起搏二者在术中起搏参数比较 ,以及流入道起搏电极植入方法。方法 :选择本院行永久性心脏起搏器安置术的 67例患者为研究对象 ,在右室心尖部起搏电极不易固定或测试起搏参数不理想时 ,改为右室流入道起搏 (12例 )。结果 :①右室心尖部及流入道两种位置起搏阈值、R波振幅、心肌阻抗比较无显著性差异 ;②术后随访 2~ 14个月两组病例均未发生电极脱位、感知异常、膈肌收缩。结论 :①右室流入道起搏与心尖部起搏一样是电极植入的有效部位 ;②右室流入道起搏与心尖部起搏一样心室电极植入技术简单易行 相似文献
87.
目的:根据右心室不同部位起搏时血液动力学改变,研究选择置入右心室双部位起搏器辅助治疗心脏扩大合并充血性心力衰竭(CHF),观察临床效果及心脏功能;方法:对13例在心内科住院的扩张型心肌病、缺血性心肌病、心动过速性心肌病所致心力衰竭的患者,男9侈4,女4侈4,年龄36岁~75岁(平均58.61岁),心功能均在Ⅲ级~Ⅳ级(NYHA),均有置入起搏器的适应证。术中通过Swan—ganz漂浮导管对右心室内不同部位起搏10分钟后测各部位的急性血液动力学改变,然后置入右心室双部位起搏器(右室流出道应用主动固定电极)。术后应用心电图、超声心动图观察右心室双部位起搏的血液动力学效果;结果:全组13例患者术中检查及置入右心室双部位起搏器均获成功。测得右心室流出道起搏(RV—OT)和右室心尖部(RVA) 右室流出道(RVOT)起搏时各参数均较单纯右室心尖部(RVA)为好。置入心脏起搏器后观察射血分数从0.31提高至0.39,左室充盈时间延长,二尖瓣返流量减少,心脏缩小,心脏功能平均提高Ⅱ级。其中一例心功能由Ⅳ级提高至I级~Ⅱ级;结论:初步血液动力学观察提示,右心室双部位起搏能改善充血性心力衰竭患者的心功能。 相似文献
88.
Nabil El-Sherif 《The International Journal of Cardiac Imaging》1991,7(3-4):141-150
In this work the electrophysiologic mechanisms of ventricular arrhythmias have been briefly summarized. Ventricular arrhytmias can be caused either by pacemaker activity or by reentrant excitation. Enhancement of normal automaticy can generate a parasystolic rhythm in normal fibers. Abnormal automaticity may arise fom fibers in which maximum diastolic potential has been reduced by a variety of interventions. Triggered activity is caused by either an early (EAD) or delayed (DAD) afterdepolarization and requires a prior normal action potential for initiation. While there is growing evidence that EAD-induced triggered activity plays a significant role in the Long QTU syndrome and Torsade de Pointes, no clinical arrhythmias has definitely been ascribed to DADs, although DADs have been recorded in man after acute digoxin intoxication.Ventricular arrhytmias can be also caused by reentrant excitation, which can be subdivided into reflection or circus movement reentry (CMR). In the reflection model impulses in both directions are transmitted over the same pathway. In the CMR three models can be differentiated: the ring model, which requires a fixed anatomical obstacle; the figure-eight model and the leading circle model, where functional rather than fixed anatomical obstacles are involved.Abbreviations AV
atrio-ventricular
- CMR
circus movement reentry
- DAD
delayed afterdepolarization
- EAD
early afterdepolarization
- ECG
electrocardiogram
- LV
left ventricle
- MAP
monophasic action potential
- MF
muscle fiber
- PF
Purkinje fiber
- RV
right ventricle
- TdP
Torsade de Pointes 相似文献
89.
Ruptured sinus of Valsalva aneurysms are rare. We report a case in which the usual clinical manifestations were not present and the patient was initially treated as an acute pulmonary embolus. Despite three negative echocardiograms an intra-cardiac shunt was suspected because of a persistently elevated mixed venous oxygen saturation. Cardiac catheterisation confirmed the diagnosis. Surgical repair was performed and post operative recovery was uneventful. 相似文献
90.
Invasive cardiac pacing has proved useful in the induction and termination of reentrant sustained tachycardias. In one of our two cases, programmed ventricular extra-stimulation was used to induce sustained ventricular tachycardia from the endocardial surface of the right ventricle. Induced ventricular tachycardia was terminated by burst ventricular pacing with an external cardiac pacemaker. In our second patient, external pacing was effective at inducing and terminating sustained supraventricular tachycardia. These patients illustrate that the principles of terminating sustained reentrant tachycardia with invasive pacing may also apply to noninvasive external pacing. The usefulness of this approach in treating reentrant tachycardias needs further evaluation. 相似文献