右房峡部传导特性与心房扑动诱发的关系

在 10例室上性心动过速消融后及 2例窦性心动过缓心脏电生理检查中 ,依次进行低侧右房和冠状静脉窦口刺激 ,检出右房峡部双向阻滞 6例、双向传导 2例、单向阻滞 4例。在 3例峡部逆钟向阻滞者 ,低侧右房刺激诱发出短阵顺钟向心房扑动 (简称房扑 ) ;在 1例峡部顺钟向阻滞者 ,冠状静脉窦口刺激诱发出短阵逆钟向房扑。提示在无临床房扑史但有右房峡部单向阻滞者 ,可诱发短阵房扑 ,诱发房扑的类型与峡部阻滞方向及刺激位点有关。     

成功消融右房峡部依赖型心房扑动的径线位置及临床特点

目的总结成功治疗右房峡部依赖型心房扑动(简称房扑)的消融线位置及临床特点。方法收集2009年至2014年间成功消融的右房峡部依赖型房扑患者的临床资料,分析总结成功消融的消融线位置及特点。结果共274例患者入选,年龄[54.1±13.8(14~84)]岁,65例(23.7%)为心脏外科术后患者。术中266例(97.1%)在6点钟位置消融成功,8例(2.9%)在7-8点钟位置消融成功。后者心脏外科术后的比例及再次/多次消融的患者比例明显高于前者。结论对于绝大部分右房峡部依赖型房扑患者,于6点钟位置消融即可,极少数患者需于偏游离壁位置(7-8点钟)方可消融成功,特别是对于心脏外科术后患者及曾消融失败的患者。     

右房解剖的左手模式（88）

右心房的解剖因涉及到上下腔静脉、右心耳、冠状窦、卵圆窝等,使其结构十分复杂。近十年来,右房在心脏电生理和起搏治疗中越显重要。在X线影像,右房各部分解剖的位置较难界定,尽管有了三维标测技术,但在起搏器、ICD以及CRT的植术入中,熟练掌握右房的解剖越来越重要。     

右室间隔部起搏新进展

右室间隔部（right ventricular septum,RVS）接近希氏束,右室间隔部起搏（right ventricular septal pacing,RVSP）理论上能获得较好的血流动力学效果和保护左心功能,但临床研究却提供了相互矛盾的结果。本文将RVSP研究进展做一综述,为临床选择适宜的起搏位点提供参考。     

右室间隔部起搏一定优于心尖部起搏吗?

起搏器心室电极通常放置在右心室心尖部,然而大量随机临床试验研究发现,双腔起搏器/右心室心尖部(DDD/R)起搏与单腔心室起搏器(VVI/R)相比不能减少死亡率,其原因可能与心尖起搏密切相关。因此,右室间隔部起搏应运而生,因其可获得接近心脏生理性激动顺序,在血流动力学、心电生理和病理生理学上有一定优势,然而在一些长期和短期的随访研究中发现,间隔部的起搏对已有左室功能损伤的患者较有利,对左室功能正常患者作用不明显,而且主动电极有心脏穿孔和冠状动脉损伤的潜在风险。因此,应综合权衡患者年龄、基础疾病状态以及预计达到的结果选择生理性起搏位点,以降低起搏器和埋藏式心律转复除颤器治疗中心房颤动和心力衰竭的发生率和总体死亡率。     

简化三维电解剖标测指导峡部依赖性心房扑动的消融

目的探讨简化三维电解剖标测指导峡部依赖性心房扑动(简称房扑)消融的有效性。方法 59例峡部依赖性房扑患者,分别接受多极导管指导的常规法消融(n=22)及简化三维电解剖标测指导的消融(Carto法,n=37)。消融终点设定为双向跨越峡部的传导完全阻滞。结果 56例消融成功,两组成功率分别为86.4%和100%,(P=0.047);两组复发率分别为15.8%和0%,(P=0.035);Carto组较常规组手术耗时更短(68.2±6.9 min vs101.4±15.4 min,P<0.01)、X线暴露时间少(5.8±2.2 min vs 18.1±3.7 min,P<0.01),且射频消融时间更短(9.1±4.1 min vs 14.8±6.0 min,P<0.001)。3例常规组消融失败患者二次消融时交叉入Carto组均获得手术成功。Carto组显示峡部宽度的增加提示更长的X线暴露时间及射频消融时间。结论简化的峡部三维重建对指导峡部依赖性房扑的消融具有优势,且对常规法术后复发的房扑再次消融能获得有效成功。     

对比观察射频消融右房后位峡部和间隔峡部治疗 …

对比观察射频消融右房后位峡部和间隔峡部治疗心房扑动（简称房扑）两种方法的疗效。４１例房拟患者随机分为后位峡部组（１８例）和间隔峡部组（２３例）,消融线径分别为三尖瓣环一下腔静脉和三尖瓣环一欧氏嵴。成功消融绺为房扑不能诱发和峡部呈完全性双向阻滞。结果：４０例消融成功（９７．６％）,无并发症。后位峡部组３例和间隔峡部组２例在首选消融方法和后,秘国一种消融方法获得成功。两组患者的放电次数和手术时间均显著     

胆总管、胰管汇合部的应用解剖

为给经内镜逆行胆胰管造影、经内镜乳头括约肌切开术等临床诊断、治疗提供应用解剖学资料，对７０例人尸体的胆总管与胰管汇合部进行了解剖、测量并统计。结果胆总管入十二指肠角：成人４１．１±１．７５ｏ、儿童４０．１±１．７２ｏ，胆总管肠壁内段长度：成人１．０４±０．４２ｃｍ、儿童０．８９±０．６３ｃｍ；十二指肠大乳头位于十二指肠降部中１／３者４４例，占总例数的６７％，其余开口于降部的上１／３或下１／３；十二指肠大乳头至胃幽门间距：成人９．８４±１．５８ｃｍ、儿童８．２６±１．６４ｃｍ；至上颌中切牙间距：成人７４．５８±１．７７ｃｍ，儿童６９．６３±２．０８ｃｍ，胆总管、胰管汇合共同开口４１例，占分型数５０例的８２％，其余为分别开口。结果提示胆总管入角越小其肠壁内段长度越长，十二指肠大乳头位于降部中１／３后内侧壁者及胆总管与胰管共同开口者占多数，并对其临床意义展开讨论     

对比观察射频消融右房后位峡部和间隔峡部治疗典型心房扑动的疗效

对比观察射频消融右房后位峡部和间隔峡部治疗心房扑动 (简称房扑 )两种方法的疗效。 41例房扑患者随机分为后位峡部组 ( 18例 )和间隔峡部组 ( 2 3例 ) ,消融线径分别为三尖瓣环—下腔静脉和三尖瓣环—欧氏嵴。成功消融终点为房扑不能诱发和峡部呈完全性双向阻滞。结果 :40例消融成功 ( 97.6 % ) ,无并发症。后位峡部组 3例和间隔峡部组 2例在首选消融方法失败后 ,改用另一种消融方法获得成功。两组患者的放电次数和手术时间均无显著性差异。平均随访 12 .4± 6 .8个月 ,在后位峡部消融成功者中 ,有 2例房扑复发。结论 :射频消融右房后位峡部和间隔峡部治疗房扑均安全有效 ,两种方法互补可以提高消融的成功率     

Incremental Pacing for the Diagnosis of Complete Cavotricuspid Isthmus Block During Radiofrequency Ablation of Atrial Flutter

Incremental Pacing for the Diagnosis of Cavotricuspid Isthmus Block.   Background: Complete conduction block of the cavotricuspid isthmus (CTI) reduces atrial flutter recurrences after ablation. Incremental rapid pacing may distinguish slow conduction from complete CTI conduction block.
Methods and Results: Fifty-two patients (67 ± 9 years) undergoing 55 CTI ablation procedures were included. With ablation, double potentials (DPs) separated by an isoelectric line of ≥30 ms were obtained. Incremental atrial pacing (600–250 ms) was performed from coronary sinus (CS) and low lateral right atrium (LLRA). A <20 ms increase in the DPs distance during incremental pacing was indexed as complete CTI block. In 8 patients, an initial <20 ms DPs distance increase was noted; direct complete isthmus block was suggested and no additional ablation performed. In the remaining, the CTI line was remapped for conduction gaps and additional radiofrequency energy pulses applied. Complete block, as indexed by incremental pacing, occurred in 46 of 55 procedures, with one flutter recurrence (follow-up 8 ± 2 months): DPs interval variation of 116 ± 20 to 123 ± 20 ms (CS), P = 0.21; and 122 ± 25 to 135 ± 35 ms (LLRA), P = 0.17. The remaining 9 patients (persistent rate-dependent DPs increase) presented 3 flutter recurrences, P = 0.01: DP distance from 127 ± 15 to 161 ± 18 ms (CS), P < 0.001; and 114 ± 24 to 142 ± 10 ms (LLRA), P = 0.007.
Conclusion: Incremental pacing distinguishes complete CTI block from persistent conduction. Such identification, accompanied by additional ablation to achieve block, should minimize flutter recurrences after ablative therapy. (J Cardiovasc Electrophysiol, Vol. 21, pp. 33–39, January 2010)     

Characteristics of the Cavotricuspid Isthmus in Predicting Recurrent Conduction in the Long-Term Follow-Up

Background: The characteristics of cavotricuspid isthmus (CTI) in patients with atrial fibrillation (AF) and flutter that may predict recurrence of flutter is not known. We aimed to investigate the CTI characteristics in patients who underwent a second ablation procedure for recurrent AF after previous combined pulmonary vein (PV) and CTI ablation.
Methods: Among 196 consecutive patients with drug-refractory symptomatic AF who underwent PV isolation and CTI ablation with bidirectional isthmus block, 49 patients (age 50 ± 12 years, 43 males) had recurrent AF and received a second procedure 291 ± 241 days after the first procedure. Right atrial angiography for the evaluation of the CTI morphology, and the biatrial contact bipolar electrograms were obtained before both procedures.
Results: In the second procedure, 11 (group 1) of the 49 patients demonstrated recovered CTI conduction. Compared with the patients without CTI conduction (group 2, n = 38), group 1 patients had a higher frequency of a pouch-type anatomy (82% vs 13%, P < 0.001), longer CTI (34.0 ± 8.6 vs 25.5 ± 7.5 mm, P = 0.01), longer ablation time, and larger number of radiofrequency applications; furthermore, the preablation bipolar voltage decreased along both the CTI and ablation line in group 2, whereas it remained similar in group 1 in the second procedure.
Conclusions: A high (22%) percentage of CTIs exhibited recurrent conduction in the long-term follow-up. The CTIs with recurrent conduction had a higher incidence of a pouch and longer length compared with those without recurrent conduction.     

Further Evidence for the “Muscle Bundle” Hypothesis of Cavotricuspid Isthmus Conduction: Physiological Proof,with Clinical Implications for Ablation

Two Line Flutter Ablation . Introduction: It has been suggested that the cavotricuspid isthmus (CTI) is composed of discrete muscle bundles with preferred paths of conduction. An ablation technique targeting high‐voltage local electrograms (maximum voltage guided or MVG technique) has been described with the aim of preferentially targeting the muscle bundles. We hypothesized that the MVG technique could provide isthmus block even if the high voltage targets were clearly separated on different ablation lines. In contrast, conduction over a continuous sheet of muscle would require a single continuous ablation line. Methods: Twenty‐two consecutive patients (mean age 65 ± 11.7, 5 females) underwent ablation using the MVG technique on 2 noncontiguous lines in the CTI. Ablation lesions were first applied at the septal aspect of the CTI, targeting only the ventricular (anterior) aspect of the annulus. A line distinctly lateral and noncontiguous to the first was then chosen to target high voltage potentials on the atrial (posterior) aspect of the CTI. Results: Complete CTI block was achieved in all study patients without complication. A mean of 7.8 ± 3.7 ablation lesions were required. Mean ablation time was 401.0 ± 414.5 seconds. Conclusion: Two nonoverlapping incomplete lines of ablation in the CTI consistently lead to bidirectional conduction block. This further supports the hypothesis that conduction over the CTI occurs over discrete muscle bundles. These bundles can be targeted individually for ablation without the need to ablate a continuous line over the CTI. (J Cardiovasc Electrophysiol, Vol. 24, pp. 47‐52, January 2013)     

Local Electrogram-Based Criteria of Cavotricuspid Isthmus Block

INTRODUCTION: The efficacy and outcome of cavotricuspid isthmus ablation guided by local electrogram-based criteria of linear block were prospectively assessed. METHODS AND RESULTS: In 40-consecutive patients (age 65+/-11 years) with typical right atrial (RA) flutter (cycle length = 255+/-31 msec), radiofrequency (RF) energy was delivered at electrograms in the isthmus coinciding with the center of the ECG plateau until termination of flutter, followed by local assessment of isthmus conduction during slow rate low-lateral RA pacing. 'Gaps' in the ablation line were located in the form of single or fractionated potentials centered on the isoelectric intervals of adjacent double potentials and ablated. Complete linear isthmus block was defined by the achievement of a complete corridor of parallel double potentials from the right ventricle to the inferior vena cava edge. Applications of 11+/-7 RF applications were required in all patients to achieve a complete line of double potentials separated by an isoelectric interval of 120+/-26 msec (range 60 to 190). After 6+/-3 RF applications, 6 (15%) patients had evidence of isthmus block using indirect RA activation sequence mapping without a complete line of double potentials. 5+/-5 further RF applications of eliminated local conduction and achieved complete linear block without altering descending septal RA activation. Conduction recovery occurred in 20 (50%) patients--1.85 times per patient-indicated by reversed changes in local electrograms eliminated by further ablation of the recovered gaps. After discharge, two recurrences (5%) occurred during a follow-up of 16+/-2 months. CONCLUSION: Double potential mapping is an effective assessment modality for local isthmus conduction. Slow conduction limited to the ablation line is observed during ablation in 15% of patients.