Development of totally implantable electromechanical artificial heart systems: Baylor ventricular assist system

An implantable electromechanical ventricular assist system (VAS) intended for permanent use has been developed. It consists of a conically shaped pumping chamber, a polyolefin (Hexsyn) rubber diaphragm attached to a conically shaped pusher-plate, and a compact roller-screw actuator. Design stroke volume is 63 ml. The device weighs 620 g, and has a total volume of 348 ml. The pump can provide 8 L/min flow against 120 mm Hg afterload with a preload of 10 mm Hg. The inner surfaces are biolized by dry gelatin coating, with inflow and outflow ports accommodating tissue valves. Three subacute in vivo validation studies have been conducted in calves up to two weeks. The entire system functioned satisfactorily in both the fill/empty and the fixed-rate modes. There was no thromboembolic complication without anticoagulation. The pump showed reasonable anatomical fit inside the left thorax. This VAS is compact, efficient, quiet, and easy to control.     

Changes in patterns of left ventricular hypertrophy after aortic valve replacement for aortic stenosis and regurgitation with St. Jude Medical cardiac valves

In this study, we analyzed the extent and pattern of regression of left ventricular (LV) hypertrophy after aortic valve replacement in patients with aortic stenosis (AS) and compared the results with those of another group of patients with aortic regurgitation (AR). Seventy patients who underwent isolated aortic valve replacement were divided into 2 groups. Group 1 was comprised of 29 patients who underwent aortic valve replacement for aortic stenosis, and Group 2 of 41 patients who underwent aortic valve replacement for aortic regurgitation. A third group of 10 healthy subjects served as a healthy control group. Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up, a significant reduction in the left ventricular mass was found in both groups, but it remained significantly greater than in the healthy control group. The ratio of LV wall thickness to radius (th/r) in Group 1 decreased significantly, and at follow-up it was within the normal value. In Group 2, the th/r ratio increased, and at follow-up it was within the normal value. After aortic valve replacement, the wall thickness remained significantly greater than normal for patients with AS, and the chamber radius remained significantly greater than normal for patients with AR. For these reasons, LV hypertrophy still existed in both groups at postoperative follow-up. The actuarial survival rate was 85.3% at 16 years for Group 1 and 83.4% at 18 years for Group 2. There was no significant difference in the long-term survival rates between the 2 groups. Actuarial freedom from valve-related events was 91.9% at 16 years for Group 1 and 82% at 18 years for Group 2. There was no significant difference in the valve-related event free curves between groups. After 5 years of follow-up, th/r reached normal for both groups, indicating remodeling of the LV geometry after aortic valve replacement.     

Design and test of a vascular access device

Transarterial left ventricular assist devices (LVADs), such as the Hemopump, IABP, and PUCA-pump, are meant to be introduced into the body via the femoral or axillary artery without major surgery. For certain applications, introduction is performed directly into the aorta via an open thorax procedure. A prototype of a vascular access device has been realized that allows direct access into the aorta as an alternative for the common surgical graft anastomosis suturing technique. The device consists of a metal tube acting as a circular knife to cut a hole in the aortic wall, a screw to store the removed part of the aortic wall, and a plastic tube that is introduced through the hole and tightly connected to the aortic wall. The device could be placed without aortic clamping. The device has been tested on a slaughterhouse porcine aorta. A low-pressurized aorta appeared to be the worst case; thus, two animal experiments in the low-pressurized pulmonary artery were performed. No leakage occurred for pressures between 40 and 300 mm Hg.     

Balloon Dilatation of the Pulmonary Valve in a Patient with Pulmonary Atresia and Intact Ventricular Septum Using a Commercially Available Radiofrequency Catheter

Using a commercially available 5F deflectable radiofrequency catheter, we have succeeded in percutaneous valvotomy of an imperforate pulmonary valve and consecutive balloon dilatation in a baby with pulmonary atresia and intact ventricular septum. After the procedure, right ventricular systolic pressure fell from 125 mmHg to 65 mmHg, and right ventriculography demonstrated anterograde blood flow into the pulmonary arteries. There were no major complications. Doppler echocardiography at 1 year after the procedure demonstrated a pressure gradient across the pulmonary valve of 20 mmHg with mild pulmonary and tricuspid regurgitations.     

Left Ventricular Anomalous Muscle Band and Electrocardiographic Repolarization Changes

A child with considerable electrocardiographic (ECG) repolarization abnormalities is reported in whom, after clinical and hemodynamic evaluation, only a large muscular false tendon within the left ventricular cavity was found. The genesis of the ECG changes in such cases is discussed, and the differential diagnosis from apical hypertrophic cardiomyopathy is analyzed.     

参龙降压灵对自发性高血压大鼠血压及血浆ET、CGRP含量的影响

目的与方法本实验观察了中药制剂参龙降压灵对自发性高血压大鼠（ＳＨＲ）血压、血浆内皮素（ＥＴ）及降钙素基因相关肽（ＣＧＲＰ）含量及心室结构的影响,并与尼群地平（ｎｉｆｅｄｉｐｉｎ）及牛黄降压丸作对比。结果各给药组给药１－８周后血压均比ＳＨＲ对照组明显降低（Ｐ＜０.０５－０.０１）,给药６周后参龙降压灵大剂量组血压下降幅度最大,效果优于小剂量组及其他两给药组（Ｐ＜０．０５－０．０１）。各给药组心室结构各参数多有降低,虽无统计学意义（可能例数较少）,但已显示出心室肥厚逆转的趋势。各给药组ＳＨＲ血浆ＥＴ含量均有明显降低,ＣＧＲＰ含量升高（Ｐ＜０.０５－０.０１）,而大剂量参龙降压灵作用更显著,与Ｗｉｓｔａｒ正常组大鼠含量接近。结论参龙降压灵降低ＳＨＲ血压作用确实,有逆转心室肥厚趋势及调节血浆ＥＴ和ＣＧＲＰ含量的作用,且有一定的量效关系。     

Double Outlet Right Ventricle with Intact Atrial Septum and Restrictive Ventricular Septal Defect: An Analysis of Two Cases

Two cases of double outlet right ventricle with restrictive ventricular septal defect are described. This is an uncommon presentation that causes left ventricular dysfunction because of left ventricular outflow tract obstruction. The presence of an intact atrial septum leads to severe pulmonary hypertension, which tends to aggravate the right ventricular output. In the presence of a normal left ventricle, the authors suggest the possibility of enlargement of the ventricular septal defect in order to perform a biventricular repair. The association of a supramitral valve ring in both cases, and the isolation of the left subclavian artery and an aortopulmonary fenestration in one of these cases, are also discussed. In addition we explore factors that cause restrictive ventricular septal defects as well as the mechanisms that may lead to spontaneous closure of ventricular septal defect in a double outlet right ventricle.     

Lateral asymmetries in the trigeminal ganglion of the male rat

We have applied stereological methods to estimate the number and perikaryal size of primary sensory neurons in celloidin-embedded trigeminal ganglia of male albino rats, specifically looking for inter-individual and side variability. The mean total number of neurons per ganglion was 35,300, with a moderate variability among ganglia. On average, 66% of the neurons were classified as A-type and 34% as B-type. Although for individual cases there could be notable side differences in the number of neurons of each type, on a population basis these differences were not significant. Mean neuronal volume was four times larger for A- than for B-cells, and both populations exhibited a moderate variability among individuals. High intra-animal side differences were found for A-cells, which were on average a significant 23.5% larger in the right ganglia. B-cells did not show significant side differences. The distribution of individual volumes around the mean value was consistently skewed to the right, particularly in the case of A-cells, which partially overlapped with the largest B-cells. In the right ganglion the distribution of A-cells, but not of B-cells, showed a rightward bias, revealing the increase in bigger neurons. The existence of larger A-type neurons in the right trigeminal ganglion may provide a structural substrate for some somesthetically based complex behaviors which are best performed by rats using their right vibrissae.     

室性早搏的快速检测方法

提出一种利用相关性和RR间期比相结合的快速室性早搏的检测算法.该算法具有一定的病人自适应性.通过MIT-BIH心律失常数据库的验证,该方法对Normal和PVC有很高的识别率.     

心电图劳损改变与高血压预后因素的关系探讨

目的 探讨心动图劳损改变与高血压预后因素的关系.方法 对31例有劳损的高血压患者与38例无劳损的高血压患者的预后因素进行对比分析.结果 有劳损组在空腹血糖水平、尿白蛋白/肌酐比值、超声心动图室间隔或左室后壁厚度、颈总动脉内中膜厚度、心脑肾疾病史方面均比无劳损组高,差异有显著性(P＜0.05或P＜0.01);有劳损组的高密度脂蛋白胆固醇水平比无劳损组低,差异有显著性(P＜0.05);而有劳损组总胆固醇水平和腰围与无劳损组相比虽较高但差异均无显著性(P＞0.05).结论 心电图劳损改变与多种高血压预后因素相关,可做为高血压危险分层及高血压疗效评价的一个有用指标.