Electrophysiologic characteristics and results of radiofrequency catheter ablation in elderly patients with atrioventricular nodal reentrant tachycardia

Background

As in the general population, atrioventricular nodal reentrant tachycardia (AVNRT) is the most common regular supraventricular tachycardia in the elderly patients. We tried to compare electrophysiologic characteristics, efficacy, and risks of the radiofrequency (RF) catheter ablation of the slow pathway in elderly and young patients with AVNRT.

Methods

Between April 2001 and March 2005, 268 consecutive patients (190 females; mean age, 49 ± 14 years) with AVNRT underwent RF catheter ablation at our institution. The patients were categorized into 2 groups: group 1 consists of patients younger than 65 years (n = 156), and group 2 consists of patients 65 years or older (n = 112).

Results

Compared with the younger subgroup, elderly patients more often had structural heart disease (11.6% vs 2.5%, P = .004), but there were no statistically significant differences in sex and symptoms during tachycardia (all P > .05). AVNRT cycle length was significantly longer in group 2 than in group 1 patients (P = .005). Among the conduction intervals of tachycardia, only atrio-his interval was significantly longer in group 2 patients (P = .007). The ablation fluoroscopy time, RF pulse duration, target temperature, applied energy, and number of RF applications were comparable in the 2 groups (All P > .05). Risk of atrioventricular block, pericardial effusion, and vascular thrombosis were similar in both groups (All P > .05). During follow-up with duration of 14 months, similar rate of recurrence was observed in the 2 groups (P = .94).

Conclusions

In elderly patients, slow pathway ablation is as effective and safe as in younger patients. Therefore, when considering different treatment options in elderly patients, an increased risk of complications or lower efficacy should not be a factor in determining the best therapeutic approach.     

多型房室结折返性心动过速的机制和射频导管消融

目的分析多型房室结折返性心动过速（AVNRT）并存的电生理机制和射频导管消融结果。方法18例经电生理检查后行射频导管消融的多型AVNRT患者。慢快型和慢慢型AVNRT的消融方法为首选消融前传慢径（房室结右侧后延伸）,快慢型AVNRT的消融方法为消融最早慢径逆传心房激动部位。消融成功的标准为消除1：1前传慢径,消除快慢型AVNRT的逆传慢径,不能诱发任何类型AVNRT。结果11例在消融前的电生理检查中诱发出2种类型AVNRT,均在三尖瓣环与冠状静脉窦口之间（房室结右侧后延伸）成功消融。7例在电生理检查中诱发出1种类型,消融此型后又诱发出另外1种类型,其中4例在房室结右侧后延伸进一步消融成功,另3例均经左侧后延伸进一步消融成功。消融术后随访6个月至8年,18例均无复发。结论对于大多数多型AVNRT,房室结右侧后延伸可能为其折返环的主要基质,消融可成功治愈多型AVNRT。在少部分多型AVNRT中,左侧后延伸与右侧后延伸可能分别作为不Ⅻ类型AVNRT折返环的主要基质,需要分别消融才能成功治愈。     

Radiofrequency catheter ablation for sinoatrial node reentrant tachycardia: electrophysiologic features of ablation sites

The aim of this study was to investigate catheter ablation of sino-atrial reentrant tachycardia (SART) and the electrophysiologic characteristics of the ablation sites. From January 1990 to October 1997, 651 patients with supraventricular tachycardia were referred and 11 patients were found to have SART. Ablation was successful in all cases with a mean number of 3.3 radiofrequency (RF) current pulses. SART terminated during 22 of 36 RF pulses. In spite of prompt termination, tachycardia could be re-induced in 3 of 11 patients with its earliest activation site shifted. At effective ablation sites, the electrograms during tachycardia were characterized as fractionated (75+/-17 ms), and 38+/-16 ms prior to surface P wave, and 42+/-18 ms prior to the high right atrium. Unipolar electrograms revealed a sharp negative unipolar deflection, so called QS pattern, in 15 of 20 sites during SART and 15 of 15 sites during sinus rhythm. During effective applications, atrial premature beats (APB) with activation sequences identical to sinus rhythm appeared in 14 of 22 cases. Effective ablation sites of SART showed fractionated electrograms during tachycardia and sinus rhythm. Unipolar electrogram with a QS pattern and APB during energy application could be an indicator of the optimal ablation sites.     

射频消融房室结折返性心动过速--比较分析老年人与青年人的电生理特点

目的初步比较和分析老年人与青年人在房室结折返性心动过速(AVNRT)射频消融方面的电生理特点.方法按年龄将AVNRT分为Ⅰ老年组(年龄(60岁)及Ⅱ青年组(14～40岁),行慢径消融,进行消融前后和组间的电生理参数比较,分析两组的电生理特点.结果Ⅰ组30例,Ⅱ组40例,均消融成功,随访无复发,亦无严重并发症出现.两组比较,Ⅰ组多合并器质性心脏病(17/30 v.s 3/40),而慢径残存率低(3/30 v.s 14/40);Ⅰ组的心动过速周长,消融前后窦性心律周长,消融后房室结前传文氏周期均较Ⅱ组延长(P<0.05).结论老年人的房室结前传电生理特性较青年人为差,但AVNRT的基本电生理特性及射频消融疗效受年龄因素影响不大.     

Slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a prolonged PR interval

Objectives. We sought to assess the safety and efficacy of selective slow pathway ablation using radiofrequency energy and a transcatheter technique in patients with a prolonged PR interval and atrioventricular (AV) node reentrant tachycardia.Background. Although both fast and slow AV node pathways can be ablated in patients with AV node reentrant tachycardia, slow pathway ablation, by obviating the risk of AV block, appears to be safer. However, the safety and efficacy of selective slow pathway ablation using transcatheter radiofrequency energy in patients with a prolonged PR interval during sinus rhythm are unclear.Methods. The seven study patients with a prolonged PR interval (mean ± SD 237 ± 26 ms) comprised three women and four men with a mean age of 31 ± 15 years. The slow pathway was targeted in all seven patients at the posterior/inferior interatrial septal aspect of the tricuspid annulus. Two patients presented with the uncommon variety of AV node reentrant tachycardia after initial fast pathway ablation; in the remaining five patients, the AV node reentrant tachycardia was of the common variety.Results. A single radiofrequency pulse at 30 W successfully abolished the slow pathway in both the anterograde and the retrograde direction in the two patients with uncommon AV node reentrant tachycardia. A mean of 5 ± 3 radiofrequency pulses were required in the remaining five patients with reentrant tachycardia of the common variety. The postablation PR interval and AH interval remained unchanged. The shortest cycle length of 1:1 AV conduction was prolonged significantly (from 327 ± 31 to 440 ± 59 ms, p < 0.01, as was the AV node effective refractory period (from 244 ± 35 to 344 ± 43 ms, p < 0.01). During a mean follow-up interval of 20 ± 6 months, no patient developed symptoms suggestive of AV node reentrant tachycardia or had evidence of second- or third-degree AV block.Conclusions. These data suggest that the AV node slow pathway can be ablated in patients with AV node reentrant tachycardia who demonstrate a prolonged PR interval during sinus rhythm.     

Effect of slow pathway ablation in atrioventricular nodal reentrant tachycardia on the electrophysiologic characteristics of the inferior atrial inputs to the human atrioventricular node

The inferior atrial extensions of the atrioventricular (AV) node have been related to the anatomic substrate of the slow pathway, but their role in AV nodal reentrant tachycardia (AVNRT) is unknown. Ten patients with slow-fast AVNRT were studied before and after successful slow pathway ablation. Simultaneous His bundle recordings from the right and left sides of the septum were made during right and left inferoparaseptal pacing. Longer stimulus to His (St-H) intervals were measured during right inferoparaseptal pacing than during left inferoparaseptal pacing (284 +/- 55 vs 246 +/- 46 ms, p = 0.005 for right His recordings and 283 +/- 56 vs 244 +/- 46 ms, p = 0.005 for left His recordings) at similar coupling intervals during AVNRT induction. After ablation, the St-H intervals at the maximum AV nodal conduction decrement were similar during right inferoparaseptal and left inferoparaseptal pacing (217 +/- 32 vs 207 +/- 21 ms, p = 0.10 for right His and 215 +/- 32 vs 206 +/- 20 ms, p = 0.13 for left His) at similar coupling intervals. The difference (DeltaSt-H) between St-H intervals during AVRNT induction or at the maximum conduction decrement and during constant pacing for right His recordings with right inferoparaseptal pacing were significantly greater than DeltaSt-H measured with left His during left inferoparaseptal pacing (173 +/- 64 vs 137 +/- 55 ms, p = 0.005) before ablation, but not after (117 +/- 39 vs 100 +/- 40 ms, p = 0.44). Resetting of AVNRT with delivery of left inferoparaseptal extrastimuli was achieved in 7 of 10 patients. In conclusion, the electrophysiologic characteristics of the right and left inferior atrial inputs to the human AV node in patients with AVNRT and their response to slow pathway ablation provide further evidence that the inferior nodal extensions represent the anatomic substrate of the slow pathway.     

Long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia: simple approach

AimsThe aim of this study was to report the short- and long-term results of slow pathway radiofrequency (RF) ablation in patients with atrioventricular (AV) nodal reentrant tachycardia (AVNRT) using a simplified approach (2 catheters and short applications of RF).Materials and MethodsThis was a retrospective study that included consecutive patients with AVNRT. We used an anatomical approach with only 2 catheters. Decremental AV nodal conduction and atrial-His conduction interval jump were measured. To detect the onset of the QRS, we used surface lead II. During the stimulation protocol, we performed S2-QRS and S3-QRS measurements. An increase in the S3-QRS3 interval of 50 milliseconds or greater in response to a decrease in the S2-QRS2 coupling interval of 10 milliseconds was defined as a discontinuous AV nodal function curve and taken as evidence of dual antegrade AV pathways. Atrioventricular nodal reentrant tachycardia was demonstrated by the presence of dual AV nodal physiology, atrial echoes, and tachycardia induction with a 1:1 AV relationship and a VA interval of less than 70 milliseconds. Short RF applications (10-15 seconds) were delivered at an intermediate point between the posteroseptal and medioseptal regions of the Koch triangle. The applications were considered effective when junctional rhythm appeared. The end point was the demonstration of slow pathway modification without AVNRT induction.ResultsThree hundred forty-four patients (age, 49.22 ± 17.47 years; 254 were female) were included. Discontinuous AV nodal function curves were found in 271 patients (78.77%), and short-term success was achieved in all patients. The anterograde jump in AV nodal conduction was abolished after RF in 222 patients (81.91%), and discontinuous AV nodal conduction and single AV nodal echo beats persisted in 49 cases (18%). The mean number of RF application was 7.79 ± 2.23, the mean number of effective applications was 4.63 ± 0.62, and the mean RF application time was 54.92 ± 8.03 seconds. The total procedure and fluoroscopy time was 29.45 ± 9.6 and 10.87 ± 2.36 minutes, respectively. After the procedure, all patients were followed up for a mean of 46.44 ± 18.89 months, and 7 patients (2%) presented AVNRT recurrences. Complications were observed in 4 patients (1.16%); no permanent AV block was observed.ConclusionIn this study, slow pathway RF ablation using a simplified approach technique is an effective and safe approach for the treatment of AVNRT.     

Cryoablation versus radiofrequency ablation of atrioventricular nodal reentrant tachycardia

Background

Ablation of the slow pathway is an established cure for atrioventricular nodal reentrant tachycardia (AVNRT). Periprocedural damage to the conduction system is a major concern during AVNRT ablation, and cryoablation (CRYO) has been suggested to improve the procedural safety compared to standard radiofrequency (RF) ablation, without reducing the procedural success.

Objective

We performed a systematic review and meta-analysis of studies comparing CRYO with RF ablation of AVNRT.

Methods

We searched PubMed, CENTRAL, the BioMed Central, EMBASE, CardioSource, clinicaltrials.gov, and ISI Web of Science (January 1980 to July 2013). No language restriction was applied. Two independent reviewers screened titles and abstracts to identify studies that compared the procedural outcomes of AVNRT ablation with either CRYO or RF energy. Two independent reviewers assessed the risk of bias according to the Cochrane Collaboration, and extracted patient, study characteristics, and procedural outcome data. Results are expressed as odds ratio (OR) or as weighted mean difference (WMD) with their 95 % confidence interval (CI).

Results

Fourteen studies (5 prospective randomized and 9 observational) with 2,340 patients (mean age range 13 to 53 years, 1,522 (65 %) females) were included in the analysis. RF ablation was performed in 1,262 (54 %) patients, while CRYO in 1,078 (46 %) patients. Acute success (abolition of dual atrioventricular node physiology or single echo beats) was achieved in 88 % of patients treated with RF versus 83 % of those treated with CRYO (OR?=?0.72, 95 % CI 0.46 to 1.13; P?=?0.157). RF ablation was associated with shorter total procedure time (WMD?=??13.7 min, 95 % CI ?23 to ?4.3 min; P?=?0.004), but slightly longer fluoroscopy time (WMD?=?+4.6 min 95 % CI +1.7 to +7.6 min; P?=?0.002). Permanent atrioventricular block occurred in 0.87 % RF cases and in no CRYO case (OR?=?3.60, 95 % CI 1.09 to 11.81; P?=?0.035). Over a median follow-up of 10.5 months (range 6 to 12 months), freedom from recurrent AVNRT was 96.5 % in the RF group versus 90.9 % in the CRYO group (OR?=?0.40, 95 % CI 0.28 to 0.58; P?<?0.001). At meta-regression analysis, no clinical or procedural variable had a significant interaction with the results above.

Conclusions

In patients undergoing AVNRT ablation, RF significantly reduces the risk of long-term arrhythmia recurrence compared to CRYO, but is associated with a higher risk of permanent atrioventricular block.     

射频消融治疗682例房室结折返性心动过速的临床分析

目的 回顾性分析射频消融术治疗 682 例慢-快型房室结折返性心动过速的疗效及安全性.方法 所有病例均先行心内电生理检杳,明确诊断后,以中、下位法行射频消融,统计消融成功率、复发率、并发症发生率、死亡率等指标.结果 射频消融成功率99.6%,复发率1.0%,并发症发生率1.3%,无死亡病例.结论 射频消融治疗房室结折返性心动过速成功率高,并发症少,复发率低.以中位法消融、延长单次有效放电时间、消融后房室结不应期延长且达到慢径消失可有效提高房室结折返性心动过速的消融成功率且明显降低术后复发率.     

磁导航辅助系统在老年人房室结双径路射频消融术中的应用和随访研究

目的 探讨应用磁导航辅助在老年房室结双径路阵发室上性心动过速患者射频消融术中的安全性、有效性及随访观察的结果. 方法经常规电生理检查证实的老年房室结双径路合并阵发室上性心动过速患者40例,20例予磁导航辅助射频消融(磁导航组),术者手动推送标测磁导管和消融磁导管到达下腔静脉上端,随后可在Niobe磁导航系统(Stereotaxis,Inc,USA)辅助下,结合自动推送系统Cardiodrive以方向导航或目标导航方式到达左心室心尖、高位左心房或Koch's三角,每次可做1～5°的方向调整和1～3 mm前进或后退的细微调整,以准确定位和贴靠靶点,并进行消融.其余20例采用常规标测电极、消融导管和手术方法行射频消融术(常规消融组).记录并分析两组的放电消融次数、手术成功率、手术并发症、放射透视的时间等参数.平均随访时间(1.5±0.4)年.结果 磁导航组成功19例,常规消融组20例,两组比较差异无统计学意义.两组均无严重并发症.磁导航组患者手术时间及放射透视时间均长于对照组,磁导航组医生平均透视时间为(4.5±0.6)min,低于对照组的(11.0±1.0)min.放电消融次数两组比较差异无统计学意义(P>0.05).随访1年两组患者均无阵发室上性心动过速复发. 结论对于老年房室结双径路合并阵发室卜性心动过速的患者,磁导航辅助下的射频消融术与常规消融术的安全性和成功率相似.但术者的放射线照射时间明显减少.     

Clinical efficacy of radiofrequency current in the treatment of patients with atrioventricular node reentrant tachycardia

Eight women (mean age 41 years, range 24 to 62) with drug-resistant atrioventricular (AV) node reentrant tachycardia underwent radiofrequency catheter ablation. Radiofrequency energy was delivered in a unipolar mode with use of a back paddle as the anode placed between the two scapulae. The total applied energy was 2,233 +/- 1,919 J. The AH interval increased from 87 +/- 13 to 113 +/- 17 ms (p less than 0.05) and the PQ interval increased from 141 +/- 15 to 169 +/- 34 ms (p less than 0.05). The anterograde Wenckebach cycle length increased from 300 +/- 41 to 320 +/- 42 ms (p less than 0.05). Retrograde conduction was abolished in five patients. Atrioventricular node tachycardia was still inducible in three patients. During a follow-up period of 9 +/- 3 months, four patients remained clinically asymptomatic without drug therapy and four patients had recurrent symptoms. Three of the latter responded to previously unsuccessful antiarrhythmic drugs and the fourth patient underwent surgical cure for persistence of tachycardia. Right bundle branch block occurred in five patients; it was permanent in four and transient in one. In conclusion, radiofrequency catheter ablation represents a valuable but still investigational therapy in patients with drug-refractory AV node reentrant tachycardia.     

Efficacy and safety of radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in the elderly

INTRODUCTION: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common regular supraventricular tachycardia in the general population as well as in elderly patients. The purpose of the study was to investigate the success and complication rate particularly regarding the induction of an atrioventricular (AV) block by radiofrequency (RF) ablation in elderly patients with and without a preexisting AV block. METHODS AND RESULTS: Between February 1998 and July 2004, all patients with symptomatic AVNRT referred for slow-pathway ablation in our institution were included and divided into two groups: group 1 patients younger than 75 years (n = 508) and group 2 patients > or =75 years (n = 70). A preexisting prolonged PR interval was present in 17 (3.3%) patients of group 1 and in 26 (37%, P < 0.0001) patients of group 2. Following successful slow-pathway ablation (follow-up time group 1: 37 +/- 22, group 2: 37 +/- 24 months) no induction of an AV block was observed in group 2 but in four patients of group 1 (0.79%) a complete heart block was induced requiring a pacemaker implantation. In group 1, 15 (2.95%) patients with a recurrence of AVNRT were readmitted for a repeat ablation procedure. No recurrences occurred in group 2. CONCLUSION: Despite a higher incidence of preexisting prolonged PR intervals slow-pathway ablation in elderly patients is both effective and safe and should be considered as the first line therapy also in this patient population.     

Clinical and electrophysiological characteristics in patients with atrioventricular reentrant and atrioventricular nodal reentrant tachycardia.

AIM: To compare clinical, electrophysiological characteristics and transcatheter ablation results between two groups of patients, one with atrioventricular reentrant tachycardia (AVRT) and the other with atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: The study population consisted of 94 consecutive patients who underwent endocavitary electrophysiological study and radiofrequency (RF) ablation: 46 patients had AVRT due to an accessory pathway with only retrograde conduction while 48 patients had AVNRT. RESULTS: In relation to general and clinical characteristics, differences between the two groups emerged regarding the age of symptom onset (25+/-16 vs 37+/-17 years, p=0.001), the prevalence of heart disease (8 vs 31%, p=0.001) and the correct diagnosis on surface ECG (50 vs 79%, p=0.001). Clinical presentation was quite similar apart from a higher prevalence of fatigue and sweating in the AVNRT group. Transcatheter RF ablation therapy results were similar. CONCLUSIONS: Patients with AVRT have a lower mean age at arrhythmia symptom onset compared with those with AVNRT and have fewer associated cardiac abnormalities. Clinical presentation is quite similar as well as their outcome after ablation. A correct diagnosis by standard ECG is more frequent in AVNRT.     

Role of intravenous isoproterenol in the electrophysiologic induction of atrioventricular node reentrant tachycardia in patients with dual atrioventricular node pathways

To assess the role of intravenous isoproterenol for the facilitation of electrophysiologic induction of atrioventricular (AV) node reentrant tachycardia, 20 patients with dual AV node pathways who lacked inducible AV node reentrant tachycardia at control study had a constant isoproterenol infusion administered and underwent repeat study. Six (30%) of 20 patients (group I) had inducible AV node reentrant tachycardia during isoproterenol infusion whereas the other 14 (70%) patients (group II) did not. Paroxysmal supraventricular tachycardia was clinically documented in all 6 group I patients compared to 3 (21%) of 14 group II patients (p = 0.002). The sensitivity and specificity of isoproterenol-facilitated induction of AV node reentrant tachycardia were 67 and 100%, respectively. The isoproterenol-facilitated induction of sustained AV node reentry was mediated by resolution of the weak link in anterograde slow pathway in 2 (33%) patients, in retrograde fast pathway in 3 (50%) and in both anterograde slow and retrograde fast pathways in 1 (17%) patient. Four group I patients were given intravenous propranolol, 0.2 mg/kg body weight, and had complete suppression of isoproterenol-facilitated induction of AV node reentry. Thus, intravenous isoproterenol is a rather sensitive and highly specific adjunct to electrophysiologic induction of AV node reentrant tachycardia in patients with dual AV node pathways but without inducible sustained AV node reentry.     

无休止性房室折返性心动过速的电生理机制及射频消融

探讨１７例无休止性房室折返性心动过速（ＩＡＶＲＴ），男１２例，女５例，平均年龄４６±１７岁，平均心动过速持续时间３６±７６天，平均心室率１８０±１７次／分，１７例中５例有心功能不全的表现，其中４例发生心动过速所致的扩张性心肌病。后间隔旁路１２例（左１１例，右１例），左和右侧游离壁旁路分别为２例和３例。显示递减性传导特性慢旁路２例。４例ＡＨ间期延长，平均１６１±６毫秒。在后间隔旁路中６例心动过速时体表心电图Ｖ１导联ＲＰ≥ＰＲ，仅有１例具有慢旁路特性。１７例全部消融成功，射频消融后随访１～３８个月均无发作。５例心功能不全者，心动过速终止后１周心功能明显改善；４例心动过速所致的扩张性心肌病平均随访１２个月，３例心脏大小和功能恢复正常，１例心脏渐趋缩小。研究结果表明，Ｉ－ＡＶＲＴ的电生理机制可能与下列因素有关：（１）旁路位置，后间隔发生率最高；（２）旁路性质，心动过速时体表心电图显示旁路逆传时间延长和慢旁路特性易发生；（３）多种因素导致房室结传导时间延长。射频消融对于根治ＩＡＶＲＴ和防治其导致扩张性心肌病具有重要的临床意义。     

射频消融治疗房室折返性心动过速对心率变异的影响

对30例(22例左侧旁道、8例右侧旁道)房室折返性心动过速患者在射频消融前后进行心率变异分析,旨在了解射频消融房室旁道前后心脏植物神经张力的改变.结果显示左侧旁道患者消融后 LFP/HFP显著性增高,提示副交感神经张力相对减低,交感神经张力相对增高.但右侧旁道患者消融后心率变异无变化.关于射频消融左侧旁道心率变异的机理及左、右侧旁道消融后心率变异变化存在差异的原因有待阐明.