预激综合征合并心房颤动的射频消融及远期随防

探讨导管射频消融阻断房室旁道治疗预激综合征（ＷＰＷ）合并心房颤动（ＡＦ）病人的远期疗效，对连续５８例ＷＰＷ合并ＡＦ进行射频消融阻断旁道并随访观察，其中男３２例、女２２例，年龄４２±１７岁，ＡＦ病史２３±１１年，发作频度为１１±９次／年，ＡＦ时心室率１７８±２７ｂｐｍ，心电图上最短ＲＲ间期为２２１±３８ｍｓ。合并器质性心脏病９例、合并心功能不全４例。５８例中右侧旁道占９０％（５２／５８）、左侧旁道占１０％（６／５８）；单旁道５５例、双旁道３例（均为右侧旁道）。右房室环游离壁旁道３７条（６１％）、右前间隔９条（１５％）、右后间隔７条（１１％）、右中间隔２条（３％）、左游离壁４条（７％）、左后间隔２条（３％）。首次消融成功率９４％，两次消融成功率１００％，３个月内心电图上预激复发３例（５％），经再次消融成功。随访２．０±１．８年，５７例不再发作ＡＦ（９８％），１例ＡＦ复发者（２％）合并Ｅｂｓｔｅｉｎ畸形和心功能不全，消融后ＡＦ发作次数比消融前明显减少，洋地黄容易控制心室率。４例心功能不全者在旁道阻断６个月后心功能恢复正常３例、改善１例。结论：短不应期房室旁道是导致ＷＰＷ病人发作ＡＦ的重要因素之一，采用导管射频消融?     

房室慢旁道的电生理表现及射频消融治疗

报道射频导管消融（ＲＦＣＡ）治疗慢旁道参与的房室折返性心动过速患者１１例。电生理检查和静脉注射ＡＴＰ（７例）试验发现：①增频刺激右室心尖部时，ＶＡ文氏点为１８３．２±２２．６（１６０～２３０）ｂｐｍ，达１１室房传导的最高刺激频率时最早心房激动部位的室房传导时间较基础频率刺激时最早心房激动部位的室房传导时间（ＢＶＡＥ）延长６８．８±２９．８（４６～１０９）ｍｓ，Ｐ＜０．０１。心室程控刺激时旁道阻滞前最早心房激动部位的室房传导时间较ＢＶＡＥ延长１０７．６±４１．８ｍｓ，Ｐ＜０．０１，表明慢旁道传导表现为传导速度慢以及出现频率依赖性递减传导和文氏阻滞。②连续心室刺激时静脉注射ＡＴＰ７例中有５例于注射后２０．６±２．０（１８～２３）ｓ出现完全性室房阻滞，另２例室房传导时间逐渐延长。提示ＡＴＰ可使慢旁道的室房传导发生阻滞或传导时间延长。③心动过速时逆传激动顺序异常，与Ｈ波同步刺激心室均能夺获心房。④ＲＦＣＡ可成功阻断慢旁道，有效靶点的室房传导时间为１３３．６±２１．１（１２８～１６０）ｍｓ，Ａ波超前最早参照点为２６．４±８．４（２０～４０）ｍｓ，有效靶点逆传房波前有旁道电位。结论：上述结果提示慢旁道的电生理特点和     

隐匿性房室旁道心电图定位特征探讨

回顾分析射频消融成功的３６５例隐匿性房室旁道患者房室折返性心动过速时的逆传Ｐ（Ｐ－）波特点，并比较Ｖ１及食管导联的ＲＰ－（ＲＰ－Ｖ１和ＲＰ－Ｅ）间期，以探讨隐匿性房室旁道的定位特征。结果显示：①Ｉ、ａＶＬ导联（简称Ⅰ－Ｌ导联）显示Ｐ－波倒置的１７５例均为左心旁道，其中左游离壁旁道１５５例、左后隔旁道２０例；Ⅱ、Ⅲ、ａＶＦ导联（简称Ⅱ－Ｆ导联）显示Ｐ－深倒７０例，其中左后隔旁道５０例中有３５例（７０．０％）、右后隔旁道３０例中有２５例（８３．３％）、右游离壁旁道６０例中有１０例（１６．７％），前两者与后者分别相比差异有显著性，Ｐ均＜０．００１。②在左心旁道中，ＲＰ－Ｖ１间期与ＲＰ－Ｅ间期相比（１６６．２±１７．８ｍｓｖｓ１１８．１±１９．２ｍｓ），差异有显著性，Ｐ＜０．０１；在右心旁道中，右前膈、右游离壁旁道ＲＰ－Ｖ１间期与ＲＰ－Ｅ分别相比（１０７．１±１８ｍｓｖｓ１５７．１±１８ｍｓ，１３２．５±１８．６ｍｓｖｓ１８９．２±２３．５ｍｓ），差异有显著性，Ｐ＜０．０１）。Ⅰ－Ｌ导联Ｐ－波倒置为左心旁道的重要表现，Ⅱ－Ｆ导联Ｐ－波深倒是后隔旁道的重要特点，两个导联上Ｐ－波均直立提示右前隔旁道，左心旁道ＲＰ－Ｅ间?     

心室频率适应式起搏对老年患者的应用价值

为探讨心室频率适应式起搏（ＶＶＩＲ）对老年人的应用价值，对１８例安置ＶＶＩＲ的老年患者按单盲交叉法随机程控为ＶＶＩＲ及ＶＶＩ两种起搏方式各四周，起搏期间作有关症状的定量评分、生活质量量表评价，并对患者进行自行选择起搏方式的调查。１６例完成上述研究者显示ＶＶＩＲ方式起搏时乏力与气急症状评分值较ＶＶＩ方式起搏时增加（３．８±１．３ｖｓ３．５±１．４，４．５±０．８ｖｓ４．３±１．０，Ｐ均＜０．０５），即症状好转；而心悸、头晕、胸闷、胸痛症状评分及每日硝酸甘油用量比较，差异无显著性（Ｐ均＞０．０５）。ＶＶＩＲ方式起搏时总体生活质量、精神状态及认知能力、社会参与性评分值较ＶＶＩ方式起搏时明显提高（１３２．６±１２．１ｖｓ１２５．０±１７．２，４０．４±４．４ｖｓ３８．４±５．７，１７．１±２．７ｖｓ１５．８±２．１，Ｐ均＜０．０５）。选择ＶＶＩＲ方式起搏者多于选择ＶＶＩ者（６２，Ｐ＜０．０５）。结果提示：ＶＶＩＲ起搏较ＶＶＩ起搏更能改善老年患者的自觉症状、提高其生活质量     

射频消融治疗儿童快速性心律失常100例

探讨射频导管消融（ＲＦＣＡ）在治疗儿童快速性心律失常中的临床价值，采用ＲＦＣＡ治疗儿童室上性心动过速（ＳＶＴ）９３例、特发性室性心动过速（ＩＶＴ）７例。结果：ＳＶＴ消融成功率为９１．４％，右侧旁道消融成功率低于左侧旁道及房室结慢径路消融的成功率（８１．８％ｖｓ９６．８％及９６．６％；Ｐ均＜０．０５）。随访３７．３±２０．７个月，８例复发，其中２例发作次数较术前减少，口服普罗帕酮可预防发作，另６例再次消融成功。ＩＶＴ首次消融均成功，随访１９．５±１０．３个月，２例复发，均再次消融成功。全组无并发症发生。结果提示ＲＦＣＡ治疗儿童快速性心律失常是有效的、安全的。     

植入起搏电极参数的测定和随访

为了解起搏阈值、起搏阻抗和感知阈值的变化，对４２根心房电极和４９根心室电极进行了随访。结果显示：心房电极慢性期起搏阈值为１．１７±０．３５Ｖ／０．５ｍｓ，出现波动者６例（２７．３％），心室电极为１．２７±０．３８Ｖ／０．５ｍｓ，出现波动者７例（３０．４％）；１９根电极的起搏阻抗在急性期均有波动，慢性期为５８５．６±１５０Ω，慢性期出现波动者２例（１０．５％）；１１根心房电极慢性期感知阈值（Ｐ波振幅）与植入时相一致。     

心内膜导管射频消融致心律失常作用的研究

通过分别比较１０条犬右房和左室导管射频消融前后的电生理检查结果和８０例房室旁道病人射频消融前后的电生理检查、心电监测和晚电位检查结果，探讨心内膜导管射频消融是否具有近期致心律失常作用。１０条犬消融前和消融后７日右房有效不应期分别为１４３±２５和１４１±２８ｍｓ（Ｐ＞０．０５），左室有效不应期分别为２３１±５６和２３７±７４ｍｓ（Ｐ＞０．０５），均未诱发出房性心动过速、心房扑动、心房颤动、室性心动过速、心室颤动等心律失常。８０例病人消融后即刻电生理检查没有诱发出上述快速心律失常；消融后随访３个月，共行２４小时心电监测３次均未发现新的心律失常，晚电位检查均为阴性。表明采用导管射频消融术治疗室上性快速心律失常没有近期的致心律失常作用，是一种相对安全的介入性治疗方法。     

心房起搏法在射频消融房室结折返性心动过速中的应用

将射频消融治疗的９４例房室结折返性心动过速（ＡＶＮＲＴ）病人按心房起搏法和常规法进行分组（分别为３９及５５例），回顾性比较两组病人的消融治疗结果，以评价这两种方法在射频消融治疗ＡＶＮＲＴ中的安全性、成功率和复发率。随访１０．８±４．５个月，总成功率为９６．８％、复发率为２．１％。与常规组相比，起搏组有效放电时间明显延长（１４５±３８ｓｖｓ８２±２６ｓ，Ｐ＜０．０１）、慢径阻断成功率高（６１．５％ｖｓ４０．０％，Ｐ＜０．０１）、一过性房室阻滞发生率低（２．６％ｖｓ１２．７％，Ｐ＜０．０５），但各种类型的永久性房室阻滞发生率和复发率无显著性差异（Ｐ＞０．０５）。表明ＡＶＮ－ＲＴ消融术中采用心房起搏法较常规法更为安全有效。     

用实验性心力衰竭制作持续性心房颤动模型

为探讨实验性心力衰竭（简称心衰）形成持续性心房颤动（简称房颤）的可行性，用２００～２５０ｐｐｍ的频率以ＶＯＯ方式起搏犬心室３～７周形成实验性心衰，在犬清醒状态下观察心衰前、后刺激诱发的房性快速心律失常。快速起搏右室３～７周，８条犬均发生充血性心衰，３周时体重由心衰前的２８±６ｋｇ降至２４±４ｋｇ（Ｐ＜０．０５）；左室射血分数由０．６４±０．０６降至０．２３±０．０９（Ｐ＜０．０１），右房直径由２５±３ｍｍ增至３６±６ｍｍ（Ｐ＜０．０１），心房不应期由１１６±５ｍｓ增至１３７±１２ｍｓ（Ｐ＝０．０１），不应期离散度无显著性改变（１６±１２ｍｓｖｓ２０±９ｍｓ，Ｐ＝０．２０），心房平均传导时间亦无显著性变化（６１±１９ｍｓｖｓ６６±２４ｍｓ，Ｐ＝０．２０）。１条犬于起搏后第６周夜间突然死亡。心衰前，８条犬均未诱发心房扑动，４条犬诱发短暂房颤；心衰后，８条犬均可反复诱发心房扑动和持续性房颤（持续时间超过１５ｍｉｎ，平均周长９５±５ｍｓ），最长者持续２４ｈ以上。结果表明起搏心室导致犬心衰可形成非瓣膜病性慢性房颤的实验模型。     

腹主动脉结扎大鼠心房纤维化的实验研究

高血压患者有较高心律失常的发生率，房性心律失常可能与左房扩大或心房纤维化有关。为观察压力负荷增高大鼠中心房纤维化的发生情况，将Ｗｉｓｔａｒ大鼠随机分成假手术组和手术组，手术组大鼠行肾上腹主动脉部分结扎。术后４，８，１２周分别测定大鼠颈动脉压及心房胶原容积分数（ＣＶＦ），结果发现：①手术组左室舒张压明显高于假手术组（４，８，１２周分别为１８．５±２．５ｋＰａｖｓ１５．７±１．９ｋＰａ，１８．６±２．７ｋＰａｖｓ１５．３±１．３ｋＰａ，１９．６±３．１ｋＰａｖｓ１５．２±１．９ｋＰａ，Ｐ＜０．０５或０．０１）。②手术组心房ＣＶＦ明显高于假手术组（４，８，１２周左、右房分别比较：４．２３±０．７６％ｖｓ２．９３±０．８７％，４．６５±１．４５％ｖｓ３．１１±１．０７％，５．６２±１．６２％ｖｓ３．２３±１．２８％；３．８８±１．１５％ｖｓ２．５１±０．８４％，４．２４±１．６５％ｖｓ２．５１±０．８４％，５．３４±１．３２％ｖｓ２．３３±１．１４％；Ｐ＜０．０５或０．０１），手术组心房ＣＶＦ有逐渐上升趋势。③左房ＣＶＦ与左室舒张压之间无直线相关关系（ｒ＝０．１６９１，Ｐ＞０．０５）。提示在高血压大鼠模型中存在心房?     

Inappropriate Sinus Tachycardia After Radiofrequency Ablation of Para-Hisian Accessory Pathways

Inappropriate Sinus Tachycardia After Catheter Ablation. Introduction : Inappropriate sinus tachycardia (IST) has been observed following radiofrequency ablation (RFA) of the AV nodal fast pathway. This study was aimed to prospectively analyze the incidence and clinical significance of IST following RFA of para-Hisian accessory pathways (APs).
Methods and Results : Twenty-eight patients (pts) with para-Hisian APs underwent RFA. An AP was defined as para-Hisian whenever its atrial and ventricular insertions were associated with a His-bundle potential ≥ 0.1 mV. RF current was always delivered at the atrial aspect of the tricuspid annulus. to a site where the His-bundle potential was < 0.15 mV. Time- and frequency-domain analysis of heart rate variability was performed in 22 patients, before and after RFA. Abolition of AP conduction was obtained in all pts, and no AV conduction alteration occurred. Six pts (21.4%) presented with IST 45 to 240 minutes after the ablation procedure. In 5 of them, IST disappeared spontaneously within 72 hours, whereas in 1 pt β-blockers were required for 2 months. The atrial potential amplitude (1.217 ± 0.264 mV vs 0.882 ± 0.173 mV, P = 0.009) and A/V potential amplitude ratio (2.633 vs 1.686, P = 0.05) were significantly higher in pts who developed IST than in those who did not. A marked decrease in heart rate variability was observed only in pts who developed IST.
Conclusion : IST is a relatively frequent complication after RFA of para-Hisian APs: it is generally short-lasting and usually does not require any treatment. IST after catheter ablation is likely to depend upon transient parasympathetic denervation of the sinus node.     

房室旁道电位的电生理特征及临床意义

以冠状窦内导管或大头消蚀导管记录10例预激综合征患者的房室旁道(AP)电位。8例前传AP电位均起源于同步ECG delta波前0～20ms,平均波幅为0.78 mV,A-AP间期多在30 ms以内,AP电位在V波前15 ms以上。4例逆传AP电位的平均波幅为0.46 mV,V-AP及AP-A分别为52 ms及34 ms。记录AP电位有助于房室旁道的准确定位及其传导特性的研究。     

Radiofrequency catheter ablation of accessory pathways during pre-excited atrial fibrillation: acute success rate and long-term clinical follow-up results as compared to those patients undergoing successful catheter ablation during sinus rhythm

The onset of recurrent or sustained atrial fibrillation (AF) is common during electrophysiological (EP) studies of accessory pathways (AP). We report our experience in patients with Wolff-Parkinson-White (WPW) syndrome in whom AF with rapid antegrade conduction over the AP occurred during an EP study and mapping and ablation were done during sustained AF, as compared to patients ablated during sinus rhythm. The study group consisted of 18 patients (group 1) with WPW syndrome who underwent catheter ablation during pre-excited AF. Two hundred and sixty-three patients, comparable for clinical characteristics, whose manifest APs were ablated under sinus rhythm formed the control group (group 2). Bipolar electrogram criteria recorded from the ablation catheter showing early ventricular activation relative to the delta wave on the surface ECG and AP potentials preceding the onset of ventricular activation were used as targets for ablation. Clinically documented atrial fibrillation was significantly more frequent and antegrade ERP of AP was significantly shorter in group 1 than in group 2 (39% vs 14%, P = 0.014 and 268 ± 37 vs 283 ± 16, P < 0.001, respectively). Procedure-related variables, acute success rates (17/18 [94%] in group 1, 251/263 [95%] in group 2; P > 0.05) and late recurrence rates (0/18 [0%] in group 1 vs 5/263 [2%] in group 2; P > 0.05) during a mean follow-up of 25 ± 9 months (range 8–52 months) did not differ significantly. Our results show that both right- and left-sided accessory pathways can be mapped and ablated safely during pre-excited AF without delay, and that acute success and recurrence rates and long-term follow-up results are similar to those of pathways ablated during sinus rhythm.     

房室多旁道的电生理特征及其射频消融治疗

目的 探讨房室多旁道的电生理特点及射频消融方法。方法 23例患者经电生理检查确定房室多旁道，应用心房和心室刺激诱发室上速，确定每条旁道的电生理特征及与心动过速的关系，按照标测部位对相关旁道逐步消融，以射频消融成功确定旁道位置。结果 23例中检出旁道49条，其中三条旁道3例；左侧多旁道12例，右侧多旁道2例，双侧多旁道9例；左侧多旁道以隐匿性为主；右侧多旁道多为显性；未见心动过速时右侧旁道前传而同侧旁道逆传现象。结论 多旁道患者应首先确定和消融与心动过速相关旁道；左侧多旁道应以诱发心动过速或快速心室起搏方法标测；右侧多旁道应同步描记12导联体表心电图，旁道消融成功可能仅见于QRS波的变化，双侧多旁道应首先消融左侧旁道。     

Immediate and long-term eff icacy and safety of catheter ablation of right anteroseptal atrio-ventricular accessory pathways

This study investigated long-term outcome of catheter ablation of right anteroseptal atrio-ventricular (AV) accessory pathways (AP) located close to the His bundle.MethodsBetween April 2003 and June 2011, 26 patients (6 females, age 35±13 years) underwent catheter ablation of right anteroseptal AP. These APs represented 10% of all 248 APs ablated within the given reference period. Elimination of AP conduction in both directions and preservation of normal AV conduction were the ablation procedure endpoints.ResultsFirst ablation was effective in 18 (69%) patients. After repeat ablation, AP was permanently eliminated in 22 (85%) patients (one, two, and three ablation procedures in 16, 5, and 1 patient, respectively). Ablation failed in 4 patients (1 procedure in 3 patients, 2 procedures in 1 patient). During 56±27 (4–102) month follow-up period since the last ablation, no late AP conduction recovery was found, and no late advanced AV block occurred. Post-ablation AV node Wenckebach point was present at the pacing rate of 176±26 (130–230) beats per minute. Of the two engaged operators, more experienced operator successfully accomplished first, second, and third ablation procedure in 14/16 (88%), 5/5 (100%), and 1/1 (100%) patients, respectively, the latter operator attained successful ablation in 4/10 (40%) and 1/2 (50%) patients at the first and second ablation procedures, respectively.ConclusionAblation of right anteroseptal AP close to the His bundle is feasible and safe. Late advanced AV block was not observed. Individual operator's experience influenced ablation efficacy.     

Characteristics and radiofrequency ablation in posteroseptal and left free-wall subepicardial accessory pathways

Accessory pathways (APs) that can only be ablated from the coronary sinus are likely to be located subepicardially. The electrocardiographic (ECG) and electrophysiological characteristics as well as the immediate radiofrequency ablation success rate and the recurrence rate were compared in 15 patients (11 posteroseptal and 4 left free-wall) with subepicardial APs and in 31 control patients with posteroseptal (15) and left free-wall (16) APs matched with age, sex, and AP location during the same study period in whom APs were successfully ablated from the endocardial approach. Patients with posteroseptal subepicardial APs had a longer tachycardia cycle length (355 +/- 32 vs 286 +/- 49 milliseconds, P < .05), a lower success rate (9 /11 vs 15/15, P = .09), and a higher recurrence rate (3/9 vs 0/15, P < .05) as compared with control patients. A negative delta wave with QS or QR pattern in lead II was present in all 4 patients with a manifest posteroseptal subepicardial AP located in the middle cardiac vein as compared with none of the 5 control patients with posteroseptal APs located in the proximal coronary sinus and 1 of the 9 control patients (P < .01). A positive delta wave in lead I along with an R/S of less than 1 in lead V 1 , and a negative delta wave in lead II, was noted in 1 of the 2 patients with left free-wall subepicardial APs and none of the 7 controls (P = .047). The local activation time is significantly shorter in the 4 patients with left free-wall subepicardial AP than in the 16 control patients (31 +/- 9 vs 89 +/- milliseconds, P = .044). CONCLUSIONS: Some ECG characteristics are suggestive of APs located in the middle cardiac vein and left free-wall subepicardial site, while a longer local activation time is characteristic of left free-wall APs. The success rate is lower and the recurrence rate higher with radiofrequency ablation in patients with subepicardial AP.     

Reappraisal of intermediate-term follow-up of radiofrequency ablation of accessory atrioventricular pathways for treatment of Wolff-Parkinson-White syndrome.

To evaluate the safety and efficacy of catheter mediated radiofrequency (RF) ablation in patients with Wolff-Parkinson-White syndrome, 125 patients with accessory pathway (AP) mediated tachyarrhythmias underwent RF ablation. Right-sided APs were ablated from the atrial aspect of the tricuspid annulus (all from the femoral vein approach) and the left-sided APs were ablated from the atrial or ventricular aspect of the mitral annulus. Immediately after ablation, 3 of 8 APs (38%) and 131 of 137 APs (95%) were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the 11 APs where RF ablation failed had a later successful DC ablation. During follow-up (3 to 22 months), 11 of the 114 patients (10%) with successful ablation had return of accessory pathway conduction (2 had recurrence of tachycardia (2%)). Complications included transient myocardial injury (peak CK-MB 15 +/- 3 IU/l), transient proarrhythmic effects (more atrial and ventricular premature beats), accidental AV block (1 patient), cardiac tamponade (1 patient) and suspicion of aortic dissection (1 patient). In successful sessions, procedure and radiation exposure time were 3.8 +/- 0.2 h and 45 +/- 4 min, respectively. This study confirms that RF ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of Wolff-Parkinson-White syndrome.     

右侧显性房室旁道合并右后隔慢旁道的电生理特点和消融治疗

报道两例右侧显性房室旁道合并右后隔慢旁道的电生理特点和消融治疗。两例显性预激综合征接受射频消融治疗 ,心房和心室程控刺激评价消融前后电生理变化。心脏标测证实两例病人存在右侧显性房室旁道 ,阻断该旁道后AV间期延长达 16 3和 16 7ms,QRS波群变宽呈完全预激形 ,程控刺激和标测证实为右后隔慢旁道 ,前传速度慢但无递减传导 ,无VA传导 (例 1)或VA递减传导 (例 2 )。消融阻断慢旁道后AV再次延长达 188ms和 2 17ms,心室预激消失 ,QRS波群呈右束支阻滞形 ,心室刺激见VA分离。结论 :两例病人为右侧游离壁显性房室旁道合并右后隔慢旁道 ,前者掩盖后者的前向传导。正常房室传导束 (AVN HPS)的传导速度慢于慢旁道是其显现前传的原因。     

Radiofrequency catheter ablation of left lateral accessory pathways via the coronary sinus.

BACKGROUND. The purpose of this study was to describe a new technique for catheter ablation of left lateral accessory pathways (APs) by radiofrequency energy applied at the epicardium through the coronary sinus wall using a unipolar configuration. METHODS AND RESULTS. In an overall group of 212 patients with left lateral APs, multiple endocardial ablation attempts of the AP were unsuccessful in eight patients. The mean +/- SD cumulative duration of previous attempts was 12 +/- 9 hours, using DC shocks and/or radiofrequency energy applied both at the atrial and/or ventricular AP insertions. Epicardial AP insertion was determined by bipolar and unipolar unfiltered distal electrograms by scanning the coronary sinus with a steerable 6F or 7F catheter with a 4-mm distal electrode. The local atrial to ventricular electrogram amplitude ratio was 0.3-1.6. At the ablation site, the catheter tip was slightly deflected toward the annulus to increase both the ventricular component of electrograms and contact with the epicardium. In four patients, epicardial electrogram timings were earlier than endocardial ones. The AP was ablated in seven of the eight patients with 20-30 W applied for 10-60 seconds. No complications occurred except a marked nonspecific pain during radiofrequency energy application; however, the catheter remained adherent to the coronary sinus wall, and its withdrawal was performed during a new radiofrequency application to decrease the risk of coronary sinus rupture. After ablation, echocardiograms, coronary artery angiograms, and levophase coronary sinus angiograms showed no abnormality in all patients except two who had a probable mural thrombus in the coronary sinus. AP conduction remained abolished for 1-10 months of follow-up in seven patients. CONCLUSIONS. Radiofrequency catheter ablation of left lateral APs can be achieved effectively and relatively safely via the mid or distal coronary sinus when endocardial approaches are unsuccessful.