血管钠肽对慢性低氧性肺动脉高压的治疗作用

目的：研究血管钠肽（vasonatrin peptide,VNP)、C型钠尿肽（C-type natriuretic peptide,CNP）和心房钠尿肽（atrial natriuretic peptide,ANP）对大鼠慢性低氧性肺动脉高压（hypoxic pulmonary hypertension,HPH）的治疗作用及其机理。方法：采用整体给药和离体血管灌流方法,测定肺血流动力学参数和离体肺动脉的等长张力变化。结果：VNP,CNP和ANP都能有效降低大鼠慢性HPH的平均肺动脉压（mPAP),P＜0．05－P＜0．01;除CNP外,VNP和ANF均能明显降低肺血管阻力（PVR）,P＜0．05－P＜0．01,其中VNP降低mPAP和PVR的作用明显大于CNP和ANP;VNP,CNP和ANP对体循环血压（mCAP）和心率（HR）均无明显影响,P＜0．05,VNP,CNP和ANP对离体肺动脉均有浓度依赖性舒张作用,但不受内皮细胞的影响;在浴槽内预先加入优降糖或心得安可显降低肺动脉对VNP和CNP的最大舒张反应（Rmax）,P＜0．05－P＜0．05,而对ANP却无明显影响。结论：VNP对大鼠慢性HPH具有显的治疗作用,它是一个新型的、强效的、非内皮依赖性的血管松驰多肽,较CNP和ANP更具有潜在的临床应用价值。     

阵发性心房纤颤患者P波离散度研究

目的 :探讨阵发性心房纤颤患者P波离散度的改变规律及临床价值。方法 :观察 41例非瓣膜性心脏病和2 1例瓣膜性心脏病阵发性心房纤颤患者最宽P波 (Pmax)和P波离散度及与左房大小关系 ,并与 30例正常人对比。结果 :阵发性心房纤颤的左房大小、Pmax、P波离散度、Pmax≥ 110ms、P波离散度≥ 40ms等均显著高于正常对照组(P <0 .0 1) ,非瓣膜性心脏病组年龄大于瓣膜性心脏病组 ,左房大小及Pmax均小于瓣膜性心脏病组 ,差异有非常显著性 (P <0 .0 1)。结论 :Pmax、P波离散度结合左房大小、年龄对预测阵发性心房纤颤的发生有重要意义。     

亚麻酸对心功能衰竭人心房肌细胞瞬时外向钾电流抑制

目的探讨亚麻酸对心功能衰竭病人心房肌细胞瞬时外向钾电流(Ito)的作用。方法应用膜片钳全细胞记录技术,记录细胞外应用亚麻酸前后人心房肌细胞Ito。结果亚麻酸对人心房肌细胞的Ito抑制作用。结论亚麻酸对人心房肌细胞Ito具有抑制作用,提示亚麻酸对心功能衰竭病人具有抗心律失常的作用。     

慢径路消融改良房室结术中出现的交界性心律之特征

目的：分析房室结慢径路消融术中出现的一过性交界性心律（ＪＲ）的特征。方法：２１例（男６例,女１５例）进行房室结改良术的房室结折返性心动过速患者,术中详细记录释放射频的次数、能量、持续时间、以及出现一过性交界性心律的时间、频率及数目,比较释放射频有效时／无效时出现的一过性交界性心律之特征有无显著性差异。结果：共进行１０６次射频电流释放,其中２１次有效（Ａ组）,８５次无效（Ｂ组）。Ａ组有１９次出现ＪＲ     

Efficacy and Mechanism of Intravenous Sotalol for Termination of Paroxysmal Supraventricular Tachycardia

ＳＶＴ ,ｉｎｃｌｕｄｉｎｇＡＶＲＴａｎｄＡＶＮＲＴ ,ｉｓａｋｉｎｄｏｆａｒｒｈｙｔｈｍｉａｏｆｔｅｎｓｅｅｎｉｎｃｌｉｎｉｃａｌｐｒａｃ ｔｉｃｅ .Ｓｏｔａｌｏｌ,ａｃｌａｓｓⅢａｎｔｉ ａｒｒｈｙｔｈｍｉｃｄｒｕｇｗｉｔｈａｄｄｉｔｉｏｎａｌβ ｂｌｏｃｋｉｎｇａｇｅｎｔｐｒｏｐｅｒｔｉｅｓ ,ｈａｓｂｅｅｎｗｉｄｅｌｙｕｓｅｄｔｏｔｒｅａｔｖａｒｉｏｕｓａｒｒｈｙｔｈｍｉａ(ｓｕｐｒａ ｖｅｎｔｒｉｃｕｌａｒａｎｄｖｅｎｔｒｉｃｕｌａｒ)ｅｆｆｉｃｉｅｎｔｌｙｉｎｗｅｓｔｅｒｎｃｏｕｎｔｒｉｅｓ[1 9]…     

先心病肺高压患者血浆心钠素在肺部的代谢及意义

探讨心钠素 (ANP)在先天性心脏病肺动脉高压形成中所起的作用。方法 :采用心钠素 (ANP)、环 -磷酸鸟苷(c GMP)特异性放射免疫分析法 ,测定 2 0例先心病肺高压患者 (实验组 )和 9例无心肺疾病者 (对照组 )肺动、静脉血浆 ANP、c GMP的含量 ,对肺部 ANP的变化及其与 c GMP变化的一致性进行分析。结果 :1实验组肺动、静脉血浆 ANP之差高于对照组 ,P<0 .0 5 ;2实验组肺动、静脉血浆 ANP之差及 c GMP之差呈负相关 ,P<0 .0 5 ;3实验组中轻度肺高压组肺动、静脉血浆 ANP之差及 c GMP之差呈负相关 ,P<0 .0 0 1。结论 :1左向右分流的先心病患者血浆 ANP在肺部的代谢量增加 ,可能用于发挥其扩张血管、支气管等作用 ,但在不同程度肺高压时 ,其代谢量有差异 ,提示 ANP在肺部的代谢可能与肺高压的形成有一定的关系。     

射频消融治疗室上性心动过速13例报道

目的 :推广应用射频消融治疗快速心律失常。方法 :穿剌动静脉 ,置入刺激和消融电极 ,经多导电生理仪明确消融靶点 ,在局部引入射频电流 ,破坏折返路径。结果 :经电生理检查诊断为室上性心动过速12例 ,特发性室性心动过速1例 ,在20～40W射频功率下经5～200s的放电消融 ,13例均获得成功(成功率100 %)。结论 :射频消融术是治疗室性心动过速 ,室上性心动过速的有效方法 ,且创伤小 ,安全可靠 ,有较高的推广价值     

Adenosine for the management of patients with tachycardias--a new protocol

We developed a new protocol for diagnosis and treatment of patientswith sustained tachycardias (heart rate > 150 beats. min^–1).The patients first underwent vagal manoeuvres; if those remainedunsuccessful, i.v. adenosine in increasing doses of 6, 12, and18 mg was administered until sinus rhythm (SR) or transientatrioventricular (AV) block, unmasking the underlying rhythm,was recorded. In the latter and in the non-responding casesother antiarrhythmics were applied. Ninety-three episodes of tachycardia in 46 patients were treatedaccording to this protocol. Six episodes (6%) were terminatedby carotid massage, 64 of the remaining 87 episodes (74%) respondedto adenosine with return to SR. Conversion to SR occurred moreoften in episodes with narrow- than in wide-complex tachycardia(81 vs 59%, P<005). To achieve SR, the mean adenosine dosewas lower in narrow- than in wide-complex tachycardia (13±8vs 21 ± 10 mg; P<0.01). The duration of asystole afteradenosine did not differ between these two groups, whereas theduration of arrhythmia after adenosine differed significantly(8.5 ± 5.8 vs 18.6 ± 22.9 s; P<0.05). Sideeffects of adenosine such as flush, dyspnoea, and chest paindid not seem to be dose dependent and occurred in about 20%. According to our protocol, in more than 75% SR was achievedin patients with sustained tachycardias after vagal manoeuvresand adenosine.     

Some observations on the mechanism of pressure related atrial fibrillation

In order to investigate the effect of atrial pressure on thepropensity of the atria to fibrillate and the mechanism of thisassociation, the right atrial pressure was changed acutely bytransfusion-bleeding in 12 anaesthetized open-chest dogs. Undervarious atrial pressures the conduction time was measured betweentwo pairs of hook electrodes positioned on the two atrial appendagesrespectively. The effective refractory period was measured bycontinuous pacing of the right atrium at a 250 ms cycle lengthat double threshold intensity and interpolating a progressivelyearlier stimulus after each eighth paced beat. The propensityof fibrillation was studied by rapid (450 min^–1) pacingof the atria at double threshold intensity for 10 s at differentatrial pressures. At a high (14 mmHg) atrial pressure the conductiontime (45.7 ± 14.2 ms) was significantly (P<0.01) longer,the effective refractory period (157.9 ± 15.2 ms) significantly(P<0.01) longer and the atrial fibrillation (11/19 or 57.9%)significantly (X² = 9.95, P<0.001) more common than at alow ( 10 mmHg) pressure (35.2 ± 11.6, 146.2 ±12.4, 3/24 or 12.5%, respectively). Analysis of variance showedthat the probability of atrial fibrillation was significantlyaffected by the atrial pressure but not by either the conductiontime or the effective refractory period The findings suggestthat an increase in right atrial pressure by acute volume overloadprolongs the inter-atrial conduction time and right atrial refractorinessand increases the propensity of the atria tofibrillate by rapidatrial stimulation. The effect of atrial pressure on fibrillationdoes not seem to be mediated by the prolonged atrial refractorinessor conduction time.     

Pulmonary venous flow as assessed by Doppler echocardiography: potential clinical applications

During the past few years Doppler assessment of pulmonary venous flow has gained increasing interest. The growing experience with the use of transesophageal echocardiography, the approach that nearly always yields registrations adequate for quantitative analysis, has markedly contributed in this respect. The Doppler-derived pulmonary venous flow pattern can be regarded as a measure of left atrial inflow and it augments the clinical significance of Doppler transmitral flow in the evaluation of diastolic left ventricular function. This article summarizes physiological background, possible applications, and limitations of Doppler echocardiography of pulmonary venous flow in clinical cardiology.