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61.
HANS KOTTKAMP M.D. GERHARD HINDRICKS M.D. MARTIN BORGGREFE M.D. GÜNTER BREITHARDT M.D. 《Journal of cardiovascular electrophysiology》1997,8(4):451-468
Catheter Ablation Techniques in AVNRT. Radiofrequency catheter ablation has been established as a first-line curative treatment modality in patients with symptomatic AV nodal reentrant tachycardia (AVNRT). The successful sites of stepwise catheter ablation approaches of the so-called fast and slow pathways strongly suggest that AVNRT involves the atrial approaches to the AV node. The typical fast pathway ablation sites are located anterosuperior toward the apex of the triangle of Koch, which also contains the compact AV node, whereas the usual slow pathway ablation sites are located posteroinferior toward the base of the triangle of Koch at a greater distance to the compact AV node and bundle of His. Accordingly, ablation studies with large patient cohorts have demonstrated that fast pathway ablation carries a higher risk of inadvertent complete AV block. Thus, the slow pathway is clearly the primary target site, and fast pathway ablation is rarely necessary. Different approaches for slow pathway ablation have been elaborated: anatomically oriented stepwise techniques, ablation guided by double potentials recorded within the area of the slow pathway insertion, and combined techniques. The modern concept of AVNRT suggests that this arrhythmia involves the highly complex three-dimensional nonuniform anisotropic AV junctional area. Accordingly, mapping and ablation studies demonstrated that the anterior approach is not identical with fast pathway ablation, and the posterior approach is not identical with slow pathway ablation. Therefore, it is essential for interventional electrophysiologists to familiarize themsdves with the anatomic and electrophysiologic details of this complex and variable specialized AV junctional region. In this review, the anatomic and pathophysiologic aspects of the AV junctional area as they relate to interventional therapy are summarized briefly, and the catheter techniques for ablation of the so-called fast and slow AV nodal pathways for the treatment of AVNRT are described. 相似文献
62.
1. It is now recognized that atrial fibrillation (AF) is not a benign condition, as it is associated with a 40% increase in mortality and a doubling of the risk of stroke. 2. The development of AF leads to mechanical, electrophysiological and cellular changes in the atria that tend to sustain AF. This process is known as atrial remodelling. 3. The three electrophysiological elements in the atria that initiate and sustain AF are: (i) shortening of the refractory period and an increase in dispersion; (ii) slowing of conduction velocity; and (iii) the presence of triggerin. foci. 4. As AF is a heterogeneous disorder, therapeutic strategies include the use of devices (pacemakers and atrial defibrillators), radiofrequency ablation (focal ablation or the creation of linear lines) and drug therapy that may reverse a remodelle. atrium. 相似文献
63.
64.
NAVIN C. NANDA M.D. SAYED MOHAMMED ABD-EL RAHMAN M.D. GAJENDRA KHATRI M.D. GOPAL AGRAWAL M.D. ADEL A. EL-SAYED M.D. HASSAN A. SHEHATA HASSANIAN M.D. MOHAMMAD KAMRAN M.D. JAMES KIRKLIN M.D. DAVID C. McGIFFIN M.D. WILLIAM L. HOLMAN M.D. ALBERT D. PACIFICO M.D. 《Echocardiography (Mount Kisco, N.Y.)》1995,12(6):619-628
In the present study, we compared three-dimensionally (3-D) reconstructed images with multiplane two-dimensional (2-D) transesophageal echocardiographic (TEE) images in 17 patients with various cardiac masses and defects. To overcome the problem of making measurements from 3-D reconstructed images, we carefully "dissected" the 3-D dataset using paraplane and anyplane 2-D sections, which were then used to obtain the maximum sizes of the cardiac masses and defects. Of the 15 vegetations and 9 abscesses detected by 3-D TEE in 7 patients, only 8 (53%) vegetations and 4 (44%) abscesses were detected by multiplane 2-D TEE (P < 0.02). Also, the exact anatomical location, shape, geometry, and extent of various cardiac masses and defects were more clearly delineated by 3-D than 2-D TEE. The maximum dimensions of cardiac masses and defects were larger by 3-D than by 2-D TEE in 17 (89%) of the 19 lesions available for comparison (P < 0.002). In addition, 3-D TEE correlated more closely than 2-D TEE when compared to surgical measurements in three patients in whom they were available. Thus, it would appear that in several instances, the exact size of the cardiac lesion could only be assessed by analysis of the 3-D volumetric dataset. Out preliminary study has demonstrated the superiority of transesophageal 3-D reconstruction over multiplane 2-D TEE in both qualitative and quantitative assessment of various cardiac mass lesions and pathological defects. 相似文献
65.
Yoshimasa Mori Masakazu Takayasu Yoshio Suzuki Masato Shibuya Jun Yoshida Hiroyoshi Hidaka 《European journal of pharmacology》1997,320(2-3):183-186
The vasodilator effects of C-type natriuretic peptide (CNP) were investigated in isolated rat cerebral arterioles. CNP caused dose-dependent vasodilation, maximally by 10.0±2.2% at 10−6 M. The median effective concentration (EC50) was 5.2×10−10 M. In contrast, atrial natriuretic peptide and B-type natriuretic peptide, other members of the natriuretic peptide family, produced little or no vasodilation. Pretreatment with methylene blue (10−4 M) abolished CNP-induced vasodilation, whereas pretreatment with NG-monomethyl--arginine or indomethacin did not inhibit vasodilation. Thus, CNP is suggested to cause significant vasodilation in cerebral arterioles via a cyclic guanosine monophosphate-dependent mechanism. © 1997 Elsevier Science B.V. All rights reserved. 相似文献
66.
We studied 100 patients who underwent an isolated aortic valve replacement (AVR) between 1974 and 1991. The patients were divided into the following two groups and compared: group A, which consisted of 40 patients operated on before 1978 who underwent continuous left coronary perfusion with blood; and group B, which consisted of 60 patients operated on after 1979 in whom St. Thomas solution was used in combination with topical cardiac cooling. Moreover, we divided the group B patients into two subgroups: group Bl, who underwent AVR before 1986 during which we administered St. Thomas solution with ice slush every 30 min; and group B2, who had AVR after 1986 in which we used St. Thomas solution with a cold saline (4°C) solution and treated with a small amount of slushed ice every 15 min. The incidence of supraventricular tachycardias was 15% in group A, 50% in group BI, and 15% in group B2. The severity of preoperative New York Heart Association (NYHA) functional class, the type of valve lesions, cardiothoracic ratio, left ventricular function, aortic clamp time, bypass time, and use of drugs did not correlate with the incidence of supraventricular tachycardias in either group A or B. In group B2 patients, we paid a lot of attention to cooling the right atrium as well as the left ventricle by immersing the whole heart using a 4°C saline solution, which led to a remarkable reduction of the incidence of supraventricular tachycardia. This fact indicates that right atrial preservation is one of the most important factors for reducing the incidence of supraventricular tachycardia. 相似文献
67.
刺激犬的颈迷走神经外周端时可引起心动过缓,而对心脏的抑制作用则逐渐减弱,表现为心率逐渐恢复(但比对照慢)。刺激后DBP立即下降,而SBP系逐渐下降,且下降程度没有DBP大。在刺激时及停止后均出现ES,其分别占刺激次数的47%和53%。在刺激停止后出现PVT(平均加速24.5次/min),PVT期间R波和BP波数不等,SV和BP轻度降低。LVET缩短和PEP/LVET比值升高,出现ES时,SV和BP较ES前显著降低。反映PVT时心脏功能降低。PVT的要理不太清楚,本研究表明反射性迷走撤退在PVT中不起作用。Q-T/Q-S_2比值增大是CA释放的间接证据。心得安可减弱PVT,阿托品可增强PVT,说明PVT由迷走静经释放CA所致。 相似文献
68.
69.
本文分析21例风湿性瓣膜病心房纤颤于手术后的转复治疗效果,指出在心瓣膜手术后转复房颤有成功率高、窦律维持时间长的效果。而术前左房大小、房颤持续时间长短和术后心功能改善程度等都直接影响转复成功与否及窦律维持期限。此外对单用电击转复和电击前采用预备药乙胺碘呋酮这两种方法进行了初步比较。 相似文献
70.
Reported is a case of a 16-month-old girl with an isolated atrial septal defect in whom severe pulmonary hypertension has developed in 26 months in spite of an important functional gradient across the pulmonic valves at a first catheterization. Individual susceptibility to an increased pulmonary blood flow is evoked. 相似文献