经导管同期封堵治疗膜周部室间隔缺损合并房间隔缺损

目的　探讨经导管介入同期治疗膜周部室间隔缺损 (VSD)合并房间隔缺损 (ASD)的可行性、方法及疗效。方法　 4例患者 ,年龄为 12～ 2 6岁。术前超声检查提示VSD合并ASD。VSD均为膜周部缺损 ,缺损直径 3～ 6mm ,缺损上缘距主动脉瓣 2～ 6mm。ASD均为继发孔型 ,缺损直径 5～ 8mm。4例患者均于术中先行左心室造影 ,确定VSD适合封堵后 ,先行VSD封堵 ,最后行ASD封堵。结果　 4例患者均经导管一次封堵治疗成功。左心室造影显示VSD呈囊袋型 3例 ,囊袋直径分别为 4、5和 10mm ,封堵器的直径分别为 4、8和 12mm。 1例缺损为管状 ,直径 3.5mm ,用 4mm的封堵器治疗成功。4例患者ASD伸展径为 6～ 10mm ,封堵器直径为 6～ 12mm。所有患者术中及术后无并发症。结论　经导管介入同期封堵治疗膜周部VSD合并ASD具有技术上的可行性、安全性和良好的治疗效果     

Non-invasive estimation of the diastolic elastic and viscoelastic properties of the left ventricle

The present study applies a non-invasive method to the quantitative evaluation of left ventricular stiffness in normal subjects and in patients with ischaemic heart disease (IHD). We have studied 20 patients with IHD and 25 healthy subjects. The third heart sound (S3) was detectable in all patients. We have correlated the energy spectrum of S3, divided into 15 Hz bands, with a series of echocardiographic parameters. The existence of a significant correlation between the spectrum energy and the diameter and thickness of the left ventricle at the moment of S3 allowed us to explore the possibility of interpreting the origin of S3 based on a mathematical model. Our hypothesis has been that, once the left ventricle starts vibrating, it behaves as a simple physical model composed of a mass and an elastic element. To this purely elastic model one can add a factor accounting for viscosity, with a damping effect, to obtain a more complex viscoelastic model. The stiffness coefficient 'k' was computed in both models from the peak frequency of S3 and the left ventricular mass at the moment of S3. Furthermore, in the viscoelastic model, the damping element 'c' was also computed. Both parameters--k and c--were significantly increased in the group with IHD compared with the control group. Although a simplification of the vibrating system, these models make it possible to obtain non-invasively information on the characteristics of the left ventricle through the combined use of echocardiography and spectral analysis of S3.     

Stability of the Defibrillation Probability Curve with the Development of Ventricular Dysfunction in the Canine Rapid Paced Model

Most patients with implantable defibrillators have diminished cardiac function. Progressive heart failure might impair defibrillation efficacy, leading to interpreted device, failure. This study sought to determine the effect of ventricular dysfunction on defibrillation energy using a biphasic endocardial system. Eleven dogs were ventricularly paced at 225 pulses/min for 2 weeks to induce ventricular dysfunction, and five control dogs remained unpaced. Dose response defibrillation probability curves were generated for each animal at baseline, after 2 weeks (at which time the pacemakers were turned off in the paced group), and then 1 week later. The defibrillation thresholds, ED₂₀, ED₅₀, and ED₈₀ (the 20%, 50%, and 80% effective defibrillation energies, respectively) were determined for each dog at each study. In the paced dogs, the mean ejection fraction fell from 55% to 25% after pacing (P < 0.0001), and rose to 46% after its discontinuation (P = 0.0002). The defibrillation threshold, ED20, ED₅₀, and ED80 remained unchanged in both the control and paced groups for all three studies, even after adjustment for dog weight or left ventricular mass. Rapid pacing produced no change in left ventricular mass. It induced ventricular cavity dilatation and wall thinning, which had opposing effects on defibrillation energy requirements, resulting in no net change of the ED₅₀ in heart failure. In conclusion, the defibrillation efficacy of a biphasic transvenous system is not changed by the development of heart failure using the rapid paced canine model.     

Coronary artery and saphenous vein graft remodeling: A review of histologic findings after various interventional procedures—part V

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effect on the site of obstruction has been termed “remodeling.” Part V of this six-part series focuses on remodeling effects of balloon angioplasty on obstructed young (≤ 1 year) and old (> 1 year) saphenous vein bypass grafts.     

左心室造影功能成像的临床应用

为探讨左心室造影功能成像的价值与限度，我们选择冠脉及左心室造影者38例行左室功能成像，观察左室壁运动情况并与节段法室壁运动定量分析比较。结果示左室收缩正常18例，其各节段EF值平均39％，节段性收缩减弱7例，无收缩3例，矛盾收缩4例，普遍性收缩减弱6例，病变节段的EF值平均5～19％，明显低于正常者（P＜0．01）。结论：左室功能成像效果直观且客观，可作为室壁运动定量分析的一个重要补充。     

人左、右心室阻抗微分心动图的比较研究

作者利用Ⅱ导心电图、心音图、颈动脉搏动图、右（或左）心室阻抗微分心动图同步描记的方法。对人左、右心室阻抗微分心动图进行了比较分析。结果显示:人的左、右心室阻抗微分心动图图形相似，波形稳定，转折明显，均有清晰的生理标志点。两种图形各相应生理标志点在时相上存在着区别．且人的左、右心室阻抗微分心动图能分别反映人的左、右心室收缩和舒张过程，说明利用人的左、右心室阻抗微分心动图能分别测定人的左、右心室收缩时间间期与舒张时间间期值，鉴别和评定左、右心室的功能。     

模拟高原和返回平原后大鼠心肌血流量的变化

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     

雌激素对左心室舒张功能影响的多谱勒超声心动图研究

目的:研究雌激素对左心室舒张功能的影响。材料和方法:利用多谱勒超声心动图记录了25例健康绝经后妇女二尖瓣口血流频谱,其中15例为雌激素替代治疗组,10例为对照组。所测参数有:舒张早期峰值速度(E),舒张晚期峰值速度(A),E加速度及减速度,并计算E/A比值及心房舒张晚期充盈分数(AFF)。结果:二组间左心室舒张期充盈明显不同,尤其是替代治疗组E/A比值高,AFF低,替代治疗组舒张早期充盈量大于对照组。结论:本研究表明长期雌激素替代治疗可以影响左心室舒张功能。     

Myocardial cooling and right ventricular function in patients with right coronary artery disease: antegrade vs. retrograde cardioplegia

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.