An atypical atrial flutter of focal origin: a study using a noncontact mapping system

We report a case of focal atrial tachycardia with appearance suggestive of atypical atrial flutter in a 57-year-old man. Based on ECG criteria, tachycardia was misclassified as atypical atrial flutter. The electrophysiological study using a noncontact mapping system revealed a focal activity within the left upper pulmonary vein ostium. This case highlights the limitations of standard electrocardiographic and electrophysiological classifications of regular atrial tachycardia. This report also shows the relevance of new mapping techniques in the successful mapping and ablation of these arrhythmias, even those arising within the left atrium.     

Left atrial flutter after segmental ostial radiofrequency catheter ablation for pulmonary vein isolation

Segmental ostial ablation to electrically isolate pulmonary veins has been performed for atrial fibrillation. Left atrial flutter that utilized a critical isthmus adjacent to the ostium of the left superior pulmonary vein was diagnosed and successfully ablated in a patient 3 months after a successful pulmonary vein isolation procedure. Documenting the cause of symptoms after pulmonary vein isolation in patients with atrial fibrillation is critical in guiding therapy.     

肺静脉前庭隔离联合左心房线性及碎裂电位消融治疗持续性心房颤动的临床研究

目的探讨肺静脉前庭隔离联合线性及碎裂电位消融治疗持续性心房颤动（房颤）的有效性与安全性。方法共45例持续性房颤患者入选本研究（其中长时程持续性房颤28例）,男性32例,女性13例,年龄（58.8±9.0）岁,病程（23.3±22.4）个月。消融步骤是先行肺静脉前庭隔离,后行线性消融,最后行心房碎裂电位消融。术后所有患者均给予服用培哚普利4 mg/d和抗心律失常药物3个月。甲状腺功能异常者,给予普罗帕酮450 mg/d,共3个月;术前未用胺碘酮者,术后即刻静点胺碘酮1 mg/min,6 h后减量为0.5 mg/min维持42 h,同时口服0.6 g/d连续1周,继之0.4 g/d连续1周,以后0.2 g/d,共3个月;术前口服胺碘酮患者,术后继续口服,0.2 g/d,共3个月。结果消融术中有9例房颤终止,2例先转变为三尖瓣峡部依赖性心房扑动,峡部消融后转为窦性心律（窦律）;3例转为房性心动过速（房速）,最早激动点或者关键峡部消融后转复为窦律;其余患者均行电复律转复为窦律。平均随访（18.2±9.2）个月,共12例患者发作房性心律失常;复发房颤3例,房速9例。结论持续性房颤患者,肺静脉前庭隔离联合左房线性及碎裂电位消融能够破坏更多的维持机制,是治疗持续性房颤的安全、有效的方法。     

Prospective evaluation of catheter ablation in patients with implantable cardioverter defibrillators and multiple inappropriate ICD therapies due to atrial fibrillation and type I atrial flutter

The high incidence of inappropriate therapies due to drug refractory supraventricular tachycardia remains a major unsolved problem of the ICD. Most of the inappropriate therapies for supraventricular tachycardia are caused by AF and type I atrial flutter with rapid ventricular response. The purpose of this prospective study was to determine the usefulness of AVN modulation or ablation for rapid AF and ablation of the tricuspid annulus-inferior vena cava (TA-IVC) isthmus for type I atrial flutter in ICD patients with frequent inappropriate ICD interventions. Eighteen consecutive patients were enrolled in this study. Twelve patients received a mean of 34 +/- 36 antitachycardia pacing (ATP) and 41 +/- 32 shock therapies for rapid AF during 49 +/- 39 months, and 6 patients a mean of 111 +/- 200 ATP and 11 +/- 8 shock therapies for type I atrial flutter during 52 +/- 37 months preceding ablation procedure. Modification of the AVN was successful in 10 (83%) of 12 AF patients, in 2 (17%) patients ablation of the AVN was performed. A complete TA-IVC isthmus block was achieved in 5 (83%) of 6 atrial flutter patients. Three (25%) AF patients had 11 +/- 24 recurrences of ATP and 0.4 +/- 1.1 shock therapies for rapid AF during 15 +/- 7 months. None of the atrial flutter patients had recurrences of inappropriate therapies for type I atrial flutter during 14 +/- 8 months, but two (33%) patients had inappropriate ICD therapies for type II atrial flutter or rapid AF. There was an overall mean incidence of 18 +/- 22 inappropriate ICD therapies per 6 months before and 4 +/- 9 per 6 months after the ablation procedure (P < 0.05). In conclusion, radiofrequency catheter modification or ablation of the AVN for rapid AF and ablation for atrial flutter type I are demonstrated to be highly effective in the majority of ICD patients with drug refractory multiple inappropriate ICD therapies.     

Empirical pulmonary vein isolation in patients with chronic atrial fibrillation using a three-dimensional nonfluoroscopic mapping system: long-term follow-up

The purpose of this study was to assess the feasibility and long-term results of empirical isolation of both superior pulmonary veins in patients with chronic AF. Although localizing and ablating the focal triggers of AF has been proven an effective approach, this strategy is time consuming, often requires multiple procedures, and carries the risk of pulmonary vein stenosis. Whether ostial electrical isolation of the superior pulmonary veins, without initial detailed mapping, is a more efficient approach is not known. The study included 71 consecutive patients who had chronic AF. Using a nonfluoroscopic electroanatomic mapping system, the left and right superior pulmonary veins were ablated circumferentially at the venoatrial junction, with the aim of achieving electrical isolation of the veins. Following ablation, if frequent atrial ectopies were present, mapping and ablation were considered. The patients were periodically followed with 48-hour Holter and loop recorder monitoring. After the ablation of the right and left superior pulmonary veins 59 (83%) of 71 patients maintained sinus rhythm without premature atrial beats. The remaining 12 patients underwent further mapping and ablation including 5 patients who required isolation of the left inferior pulmonary veins. True electrical isolation could be achieved only in 45 (31%) of the 147 targeted veins. At the latest follow-up (mean 29 +/- 8 months), 80% of the patients with upper vein isolation remained in sinus rhythm off medications, 62% of the patients maintained sinus rhythm on previously ineffective medications, and 17% continued to be in AF. Fourteen (20%) patients developed intermittent episodes of left atrial flutter, and mapping in these patients revealed large electrically silent areas in the left atrium. Empirical isolation of pulmonary veins appeared to be an effective approach to help maintain sinus rhythm in patients with chronic AF. True electrical isolation of the pulmonary veins was associated with a higher likelihood of long-term success. Left atrial flutter was seen in a significant number of patients at long-term follow-up.     

Safety of the open-irrigated ablation catheter for radiofrequency ablation: safety analysis from six clinical studies

Background: The open-irrigated catheter is used most frequently for atrial and ventricular radiofrequency ablation (RFA), and is often considered as the standard by which new ablation systems are compared. But few data have been published concerning its safety. This report provides a comprehensive safety analysis of the use of an open-irrigated catheter for RFA of atrial flutter, ventricular tachycardia, and atrial fibrillation in 1,275 patients in six rigorously monitored, prospective, multicenter studies. Methods: This analysis is of data from six studies conducted as part of both Food and Drug Administration-mandated investigational device exemption studies and postapproval studies. The six studies span a period of more than 10 years. All serious RFA complications and vascular access complications that occurred within seven days postprocedure were included. Results: The number of patients who experienced any acute serious RFA complication in these studies combined was 4.9% (63/1,275). The two earliest studies were conducted when the open-irrigated catheter was first introduced, and accounted for 55.6% of the complications. In the first atrial flutter ablation study, RFA complications decreased by 60% (15.4%-6.2%) after a proctoring program was initiated during the study. For all studies, vascular access complications ranged between from 0.5%-4.7%, and no stroke or transient ischemic attack was reported within 7 days postprocedure. No significant pulmonary vein stenosis was reported from the atrial fibrillation studies. Conclusion: A proctoring program, careful fluid management, and absence of char and coagulum contributed to the safe use of the open-irrigated RFA catheter. (PACE 2012; 35:1081-1089).     

Quality of life and occurrence of atrial fibrillation in long-term follow-up of common type atrial flutter ablation:

Objectives The ablation of common type atrial flutter is mainly performed by two approved techniques, whose efficacy and outcome in terms of quality of life have not been evaluated so far in a long-term follow-up study over years. A high proportion of patients suffer from coexistent atrial fibrillation, which may worsen the ablation result. The question arises whether one technique is more effective than the other when immediate ablation results, the occurrence of atrial fibrillation and the quality of life are compared. Considering these facts, it is reasonable to think about new ablation strategies for common type atrial flutter in the era of new concepts in catheter ablation of atrial fibrillation. Methods In a retrospective study we evaluated a detailed questionnaire in 132 patients who underwent ablation of common type between 1999 and 2004. Radiofrequency ablation was performed irrespective of coexistent atrial fibrillation either with an irrigated tip or the 8 mm tip electrode. Acute and long-term ablation outcome, and the associated quality of life, pre-, under- and post-ablation was compared in the two different ablation groups. Recurrent tachycardia were re-evaluated by 12 lead ECG analysis and assessed for both ablation groups. Results 88 (67%) of the 132 patients contacted answered the questionnaire polling the perceived benefits of the procedure. Of the other 44 patients (33%); 4 (3%) had died, 7 (5.3%) had moved, 33 patients (25%) could not be included due to missing or incoherent answers. Independent of the ablation technique there was a high acute and long-term ablation success rate at about 95%. After a mean of 3 years of follow-up this benefit persists in spite of a high proportion of recurrent tachycardia, mainly atrial fibrillation (55/88 patients, 59.1%). Despite the occurrence of secondary tachycardia, there was a high significant long-term symptomatic benefit in the state of healthy and daily practice work, evaluated with a p-value of < 0.0005. The frequency of episodes and the symptom "tachycardia" were significantly reduced after effective ablation of common type atrial flutter, p-values of 0.003 and 0.002, respectively. Therefore the need for hospitalization was significant reduced (p = 0.001). Comparison of both approaches revealed that there was no significant difference related to the incidence and occurrence of atrial fibrillation. Conclusions The two mainly accepted and applied techniques for the ablation of common type atrial flutter show an excellent outcome under the aspect of ablation efficacy and quality of life in longterm follow-up. Three years after the ablation procedure the majority of patients consider the intervention beneficial. Despite the relatively high appearance of atrial fibrillation in the long-term follow-up this effect is still traceable.     

Persistent Atrial Fibrillation Converts to Common Type Atrial Flutter during CFAE Ablation

Background: Catheter ablation of persistent and long‐standing persistent atrial fibrillation (AF) is still challenging. So far different ablation techniques have been reported, including pulmonary vein isolation, additional linear lesions, ablation of complex fractionated atrial electrograms (CFAE), and combinations of these techniques. During ablation of CFAE, the occurrence of left atrial (LA) tachycardia is well known. The occurrence of right atrial flutter on the other hand is less well described. Methods: Here, we report three patients who had been ablated because of symptomatic persistent atrial fibrillation. Summary: In all patients, AF changed into a cavotricuspid isthmus = dependent right atrial flutter during ablation of CFAE in the LA. (PACE 2010; 33:304–308)     

Noncavotricuspid isthmus-dependent right atrial tachycardia after paroxysmal atrial fibrillation ablation

Background: Atrial tachycardia (AT) is commonly encountered after atrial fibrillation (AF) ablation. But no study exclusively on noncavotricuspid isthmus‐dependent right AT (NCTI‐RAT) post‐AF ablation has been reported. The present study aims to describe its prevalence, electrophysiological mechanisms, and ablation strategy and to further discuss its relationship with AF. Methods: From July 2006 to November 2009, 350 consecutive patients underwent catheter ablation for paroxysmal AF. A total of seven patients (2.0%) developed NCTI‐RAT after left atrium ablation for AF. In these highly selected patients (two male, mean age 54 ± 11 years, mean left atrium diameter of 34 ± 7 cm), all had circumferential pulmonary vein isolation in their initial procedures and three of them had additional complex fractionated electrograms ablation in the left atrium and the coronary sinus. Results: Totally, nine NCTI‐RATs were mapped and successfully ablated in the right atrium with a mean cycle length of 273 ± 64 ms in seven patients. Five ATs in three patients were electrophysiologically proved to be macroreentry and the remaining four were focal activation. All the ATs were successfully abolished by catheter ablation. After a mean follow‐up of 29 ± 15 months post‐AT ablation, all patients were free of AT and AF off antiarrhythmic drugs. Conclusions: NCTI‐RAT is relatively less common post‐AF ablation. Totally, 2.0% of paroxysmal AF patients were revealed to have NCTI‐RAT. (PACE 2011; 34:391–397)     

Left atrial appendage isolation during ablation in the interatrial septum: Rapid recognition by continuous monitoring of appendage electrograms

Extensive atrial ablation in the setting of atrial fibrillation (AF) and atrial tachycardia (AT) can affect interatrial connections. A 76-year-old man with a history of tachycardia-induced cardiomyopathy and nine ablation procedures for AF/AT over 15 years presented with highly symptomatic recurrent AT. Previous ablation lesions included pulmonary vein isolation, left atrial posterior wall isolation, mitral isthmus line, cavotricuspid isthmus line, and the ablation of areas of fractionated electrograms. Electroanatomical mapping found the pulmonary veins and the left atrial posterior wall to be silent, as was the posterior interatrial septum and the mitral isthmus area. Activation mapping showed progression of electrograms in the left atrial appendage (LAA) from the septal aspect posteriorly, and in the coronary sinus from proximal to distal; implying the existence of a septal circuit, where extensive fractionation was noted. This was targeted, while monitoring conduction into the LAA using a multielectrode catheter. Ablation led to prompt termination of tachycardia and simultaneous LAA isolation. Immediate cessation of ablation led to recovery of conduction into LAA. Additional lesions in the interatrial septum were required to render the tachycardia noninducible, accompanied by temporary isolation of LAA. The ablation lesion sets employed while ablating AF and left AT can block many interatrial pathways, rendering conduction dependent on muscle bundles in the interatrial septum and, therefore, vulnerable to block by lesions in this area. LAA isolation has been associated with high incidence of LAA thrombus formation and stroke despite oral anticoagulation. Continuous observation of LAA electrograms during ablation can help to avoid this complication.     

Atrio-ventricular block during left atrial flutter ablation

We present a case of a patient treated with catheter ablation for atrial fibrillation aiming to pulmonary veins isolation. During ablation, atrial fibrillation organized into a left atrial flutter. Electroanatomic and electrophysiologic mapping revealed the anterior left atrium area between the mitral annulus and left atrium septum as a critical region for flutter ablation. After a few pulses of radiofrequency, complete atrio-ventricular block appeared. Finally, we propose pace mapping of the mitral annulus to detect left dislodgment of the compact atrio-ventricular node.     

Change in morphology of reentrant atrial arrhythmias without termination following radiofrequency catheter ablation

A 60-year-old woman who had previously undergone an atrial septal defect repair and had type I atrial flutter underwent electrophysiological study. After radiofrequency (RF) ablation to the isthmus between the inferior vena cava and the tricuspid annulus, type I atrial flutter was changed to atrial tachycardia following atriotomy without termination. This atrial tachycardia was eliminated by single-site RF ablation of a small lesion below the caudal end of the atriotomy scar, where continuous and fragmented potentials were recorded during tachycardia. We experienced a rare case in which RF energy changed tachycardia circuits.     

Diagnosis and ablation of atrial flutter using a high resolution, noncontact mapping system

The ablation of atrial flutter can sometimes be time consuming and unsuccessful using conventional catheter techniques especially in patients with recurrences after previous ablation procedures. Simultaneous high resolution mapping from multiple sites may overcome some of the limitations. Therefore, a new high resolution noncontact mapping system was used for diagnosis and ablation of atrial flutter in 15 patients. The mapping system consists of a catheter-mounted multielectrode array, an amplifier, and a computer workstation. Far-field potentials recorded by the multielectrode catheter are amplified, digitized, and sampled at 1.2 kHz, and digitally filtered to construct high resolution activation maps during tachycardia. Ablation catheters can be steered to target sites without fluoroscopy. In 12 of the 15 patients the analysis of the activation sequence during tachycardia showed a counter-clockwise, and in 1 of 15 patients a clockwise, rotating wavefront using the isthmus as part of the reentrant circuit. In two patients no tachycardia could be induced. In 3 of the 15 patients with previous conventional ablation procedures the gap in the line of block in the isthmus region was identified and marked on the animation model. The isthmus in the right atrium was ablated and isthmus block verified by the mapping system in all patients. No complications were observed. No recurrences of atrial flutter occurred during follow-up of 4 +/- 1.7 months. The total procedure and fluoroscopy time was 171 +/- 50.0 minutes and 24 +/- 12.7 minutes, respectively. In conclusion, the use of the new high resolution noncontact mapping system in patients with right atrial flutter is safe and highly effective. In patients with previously failed conventional ablation procedures the use of a noncontact mapping system may facilitate the identification of the gap in the line of block in the isthmus region and reablation of atrial flutter.     

Radiofrequency catheter ablation of common atrial flutter in a patient with anomalous inferior vena cava and azygos continuation

We describe a case of isthmus-dependant atrial flutter ablation with a superior approach due to an anomalous inferior vena cava (IVC), azygos, and emiazygos continuation. A 56-year-old man was referred to our institution for the treatment of a common atrial flutter. Two years prior, the patient had an attempted electrophysiological study not performed due to the inability to advance the guidewire through IVC. A computed tomography of the abdominal venous system revealed the absence of the subrenal IVC, azygos, and emiazygos continuation. Following double puncture of the left subclavian vein, two catheters were inserted into the coronary sinus and into the right atrium. Programmed atrial stimulation was performed and a sustained isthmus-dependant right atrial tachycardia was obtained. After 11 applications of radiofrequency energy with an inversion technique, sinus rhythm was restored and a repeat atrial programmed stimulation failed to induce any arrhythmia.     

心房颤动射频消融术中出现规律性快速性房性心律失常的预测因素

目的：分析心房颤动（简称房颤）经导管射频消融术中出现心房扑动、房性心动过速等规律性快速性房性心律失常（RATs）的预测因素。方法：首次行经导管射频消融治疗的497例房颤患者（阵发性房颤333例,持续性和（或）永久性房颤164例）在三维标测系统及环状标测电极导管指导下行经导管射频消融治疗（包括环肺静脉电隔离、线性消融和（或）碎裂电位消融）。术中记录RATs的发生情况,并分析RATs的可能影响因素。结果：术中共有163例患者[32．8％;阵发性房颤92例,持续性和（或）永久性房颤71例]出现195种RATs,持续性和（或）永久性房颤术中RATs的发生率显著高于阵发性房颤（43．3％比27．6％,P〈0．001）。单因素分析发现心脏外科术后（P〈0．001）、术前有RATs（P=0．010）、持续性和（或）永久性房颤（P〈0．001）、左房内径增大（P〈0．001）、左室射血分数降低（P=0．018）是房颤术中出现RATs的影响因素。Logistic多因素回归分析发现心脏外科术后[优势比（0R）=8．14,95％可信区间（CI）：I．69～39．1,P=0．0093、术前有RATsEOR=2．15,95％CI：1．35～3．42,P=0．001]、持续性和（或）永久性房颤[0R=1．71,95％CI：1．06～2．76,P=0．029]、左房内径[0R=1．04,95％CI：1．01～1．08,P=0．025]是术中出现RATs的独立预测因素。结论：房颤射频消融术中常出现RATs,心脏外科术后、术前有RATs、持续性和（或）永久性房颤、左房内径是术中出现RATs的独立预测因素。     

The 1998 NASPE prospective catheter ablation registry

The results of the NASPE Prospective Voluntary Registry are reported. A total of 3,357 patients were entered. For those undergoing atrioventricular (AV) junctional ablation (646 patients), the success rate was 97.4% and significant complications occurred in 5 patients. A total of 1,197 patients underwent AV nodal modification for AV nodal reentrant tachycardia, which was successful in 96.1% and the only significant complication was development of AV block (1%). Accessory pathway ablation was performed in 654 patients and was successful in 94%. Major complications included cardiac tamponade (7 patients), acute myocardial infarction (1 patient), femoral artery pseudoaneurysm (1 patient), AV block (1 patient), pneumothorax (1 patient), and pericarditis (2 patients). A total of 447 patients underwent atrial flutter ablation and acute success was achieved in 86% of patients. Significant complications included inadvertent AV block (3 patients), significant tricuspid regurgitation (1 patient), cardiac tamponade (1 patient), and pneumothorax (1 patient). Atrial tachycardia was attempted for 216 patients and the success rate was higher for those with right atrial (80%) or left atrial (72%) compared to those with septal foci (52%). A total of 201 patients underwent ablation for ventricular tachycardia. The success rate was higher for those with idiopathic ventricular tachycardia compared to those with ventricular tachycardia due to ischemic heart disease or cardiomyopathy. While the number of AV junction ablation were higher for those > 60 years of age, there was no significant difference in the success rate or incidence of complication comparing patients > or = 60 to those < 60 years of age. In addition, we found no differences in incidence of success or complications comparing large volume centers (> 100 ablation/year) with lower volume centers or between teaching and non-teaching hospitals.     

Long-term outcome of right and left atrial radiofrequency ablation in patients with persistent atrial fibrillation

OBJECTIVES: To investigate the clinical outcome of right and left atrial radiofrequency ablation after the first 12 months in patients with drug-refractory persistent atrial fibrillation (AF), and to identify predictors of long-term success. METHODS: We analyzed the clinical outcome of 74 consecutive patients with a follow-up >12 months who underwent right and left atrial ablation for persistent AF. Patients who did not present symptomatic or asymptomatic atrial tachyarrhythmias (AT) lasting >30 seconds after the first 3 months of follow-up were defined responders to pulmonary veins ablation. RESULTS: After a mean follow-up of 20.2 +/- 6.3 months (12-36), 52/74 (70%) patients were deemed responders. AT relapsed within the first 12 months in 19/74 (26%) patients (17 AF and 2 left atrial flutter). Among those patients who did not relapse within the first 12 months, only 3 patients (5%) presented AF after the first year of follow-up. At the multivariate analysis presence of early AT relapse and history of AF >7 years inversely correlated with a successful long-term clinical outcome. CONCLUSION: Right and left atrial ablation, alone or in association with antiarrhythmic drugs, prevented AT relapses in 70% of patients with drug-refractory persistent AF also after the first 12 months. Presence of AT relapse within the first 3 months and history of AF >7 years identified patients with a lower probability of successful long-term clinical outcome.     

三维电解剖标测系统结合肺静脉前庭电位指导心房颤动经导管消融

背景:目前常用的肺静脉前庭定位手段主要是通过三维电解剖标测(CARTO)结合X射线影像或CT影像融合等完成,这些方法均是通过解剖指导进行肿静脉前庭定位、消融,消融是否命中心房颤动(房颤)赖以维持的关键部位不得而知.目的:验证三维电解剖标测系统结合肺静脉前庭电位指导房颤经导管消融治疗的可行性.设计、时间及地点:验证性临床试验,于2007-03/2009-06在济南市第四医院及河北省人民医院心内科完成.对象:纳入药物治疗无效的症状性阵发性房颤患者51例.方法:于CARTO标测系统结合肺静脉前庭电位标测指导下行环肺静脉前庭线性消融,消融终点为肺静脉隔离,观察操作相关参数及消融成功率.主要观察指标:观察手术操作时间、X射线照射时间、手术成功率及并发症等操作相关参数.结果:51例患者均实现消融终点.平均操作时间(207±36.7)min,透视时间(38.2±14.3)min,消融时间(56.4±15.7)min.经过(17.5±3.8)个月的随访,累计40例(78.4%)无房颤、心房扑动及房性心动过速等心律失常发生.无严重操作相关并发症发生.结论:肺静脉前庭电位标测有助于肺静脉前庭的解剖定位,结合三维电解剖系统指导房颤消融效果好,安全性高,方法可行.     

Effect of Mitral Isthmus Block on Development of Atrial Tachycardia Following Ablation for Atrial Fibrillation

Background: Successful mitral isthmus (MI) ablation may reduce recurrence of atrial fibrillation (AF) and macro‐reentrant atrial tachycardia (AT) after pulmonary vein isolation (PVI) for AF. Objective: To determine if achieving bidirectional MI conduction block (MIB) during circumferential pulmonary vein ablation (CPVA) plus left atrial linear ablation (LALA) affects development of AT. Methods: Sixty consecutive patients with persistent (n = 25) or paroxysmal (n = 35) AF undergoing CPVA plus LALA at the MI and LA roof were evaluated in a prospective, nonrandomized study. Results: PVI was achieved in all patients. Bidirectional MI block was achieved in 50 of 60 patients (83%). During 18 ± 5 months follow‐up, 12 patients (20%) developed recurrent AF and 15 (25%) developed AT. Patients in whom MIB was not achieved at initial ablation had four times higher risk of developing AT (P = 0.008, 95% confidence interval 1.43–11.48) versus patients with MIB. In 12 patients with AT undergoing repeat ablation, 22 ATs were identified, with reentry involving the MI in nine, the LA roof in six, and the ridge between the LA appendage and left PVs in seven. In patients with MIB at initial ablation, recovery of MI conduction was seen in eight of 13 undergoing repeat ablation. Conclusions: AT occurring after CPVA plus LALA is often due to incomplete MI ablation, but may also occur at the LA roof, and ridge between the LA appendage and left PVs. Failure to achieve MI block increases the risk of developing AT. Resumption of MI conduction may also be a mechanism for AT recurrence. (PACE 2010; 460–468)     

Recent advances in radiofrequency catheter ablation

Radiofrequency catheter ablation has been established as a first-line treatment of various paroxysmal tachycardias, and its developments are still ongoing. As recent advances of radiofrequency catheter ablation, we can point out the following issues: 1) transaortic approach for idiopathic ventricular tachycardia(VT) of LBBB-form with inferior axis, 2) new approach guided by mid-diastolic potential for verapamil-sensitive VT, 3) pulmonary vein(PV) isolation technique guided by PV ostial circular electrogram mapping for paroxysmal atrial fibrillation, 4) new ablation strategies for macro-reentry tachycardia such as incisional atrial tachycardia and VT post old myocardial infarction guided by electro-anatomical mapping, and 5) cooled-tip ablation technique for atrial flutter and VT resistant to conventional system.