Characteristics and radiofrequency catheter ablation of septal accessory atrioventricular pathways

Septal accessory AV pathways are located in the complex AV septal space that also contains the specialized conduction system. They have unique electrocardiographical and electrophysiological characteristics to be differentiated from free-wall accessory pathways. Some of the septal pathways have AV nodelike conduction properties and produce a similar activation sequence in the retrograde conduction. Several methods have been developed to distinguish them from AV nodal pathways. Radiofrequency catheter ablation using the titration method and endocardial approach without entrance into the coronary sinus is effective in eliminating most of the septal accessory pathways without impairment of AV conduction. However, some posteroseptal accessory pathways may require energy application inside the coronary sinus, thus information of the coronary sinus anatomy is important for preventing complication.     

Slow junctional rhythm during catheter ablation of right posteroseptal accessory pathway causing transient atrioventricular block

A male patient with palpitations and syncope during an episode of atrial fibrillation was evaluated. After DC cardioversion, the ECG showed a pattern of pre-excitation compatible with right posteroseptal bypass tract. The patient was submitted to RF. During energy application a slow junctional rhythm without AV block was noted. Twenty-four hours after the procedure AV block was observed. The AV conduction was resumed spontaneously 48 hours later with unremarkable outcome up to 1 year. We postulated that the edema caused by RF application damaged the compact AV node, causing transient AV block. The AV node lesion has been manifested by a fast junctional rhythm, but in this case we observed that even a slow junctional rhythm could do it.     

Successful radiofrequency catheter ablation of an anteroseptal (superoparaseptal) atrioventricular accessory pathway from the left ventricular outflow tract

This case report describes a patient with Wolff-Parkinson-White syndrome in whom the ECG exhibited a typical pattern of an anteroseptal (superoparaseptal) accessory pathway. Successful radiofrequency catheter ablation was achieved from the septal side of the left ventricular outflow tract. It might be worthwhile to map the left side of the anterior septum if an accessory pathway potential is not appreciable along the tricuspid annulus to avoid the potential complication of AV block in patients with a typical anteroseptal accessory pathway ECG pattern.     

Percutaneous catheter ablation of atrial fibrillation

Atrial fibrillation is the most common arrhythmia and is associated with important morbidity and mortality. Antiarrhythmic therapy is recommended as initial therapy but is associated with modest efficacy and significant side effects. Over the past several years, catheter ablation has been demonstrated to provide effective and safe curative therapy for atrial fibrillation. Future investigations will assess advances in catheter ablation technology and will help to define the precise role of catheter ablation relative to alternative therapies, such as rate-control and antiarrhythmic therapy.     

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)     

Early recurrence of atrial tachyarrhythmias following radiofrequency catheter ablation of atrial fibrillation

The use of blanking periods, the immediate period postablation during which transient tachyarrhythmia episodes are not considered recurrences, has been predicated on the assumption that not all early recurrences of atrial tachyarrhythmias (ERAT) will lead to later recurrences and, as such, does not necessarily represent treatment failure. While ERAT can be expected to occur in approximately 38% of patients within the first 3 months of atrial fibrillation (AF) ablation, only half of these patients will manifest later recurrences. Clinical features related to the patient's history of AF, the index ablation procedure, and particularities of the ERAT can help identify patients at higher risk of later recurrence in whom aggressive attempts to control rhythm, including early cardioversion and reintervention, may be justified.     

心房颤动导管消融的地位和进展

心房颤动(房颤)是临床常见的心律失常之一,最大风险是血栓栓塞,常见是脑卒中。随着人口的老龄化,房颤人数持续增加,治疗问题也逐渐成为人们关注重点。房颤导管消融是其重要治疗方法之一,可明显改善房颤患者预后。且随着技术发展,消融方法也日趋成熟,故导管消融术治疗房颤地位正在逐步提升。但消融方法尚无固定术式,发生机制尚未完全明确,尤其对于持续房颤。因此房颤消融术仍存在一些问题有待进一步探索。     

Catheter ablation of atrial fibrillation: long-term outcomes

The benefits of percutaneous coronary intervention (PCI) can be offset by periprocedural complications such as acute vessel closure and stent thrombosis in the absence of adequate antiplatelet and antithrombotic therapy. Additionally, conditions occurring after 30 days post-PCI, such as in-stent restenosis or late stent thrombosis can occur. Excess antithrombotic therapy, on the other hand, carries a risk of major gastrointestinal or intracranial bleeding as well as vascular access site bleeding complications. In this review, evidence related to the various pharmacological agents for reduction of stent thrombosis available to clinicians during and after PCI will be explored.     

Steerable sheath catheter navigation for ablation of atrial fibrillation: a case-control study

Background: Lack of stable access to all desired ablation target sites is one of the limitations for efficacious circumferential left atrial (LA) pulmonary vein (PV) ablation. Targeting that, new catheter navigation technologies have been developed. The aim of this study was to describe atrial fibrillation (AF) mapping and ablation using manually controlled steerable sheath catheter navigation and to compare it against an ablation approach with a nonsteerable sheath. Methods and Results: In this case‐control‐analysis 245 consecutive patients (controls) treated with circumferential left atrial PV ablation were matched with 105 subsequently consecutive patients (cases) ablated with a similar line concept but mapping and ablation performed with a manually controlled steerable sheath. One hundred sixty‐six patients were selected to be included into 83 matched patient pairs. Ablation success was measured with serial 7‐day Holter electrocardiograms. Patients ablated with the steerable sheath showed an increase in the success rate (freedom from AF) from 56% to 77% (P = 0.009) after a single procedure and 6 months of follow‐up. With respect to procedural data no difference could be found for procedure time, fluoroscopy time, irradiation dose, and radiofrequency (RF) burning time. With the steerable sheath mean procedural RF power (33 ± 9 vs 41 ± 4 W; P < 0.0005) and total RF energy delivery (97,498 vs 111,864 J; P < 0.005) were significantly lower and the rate of complete PV isolation significantly increased from 10% to 52% (P < 0.0005). The complication rate was the same in both groups. Among different arrhythmia, procedure, and patient characteristics, the lack of early postinterventional arrhythmia recurrences was the only but powerful predictor for long‐term ablation success. Conclusions: An AF mapping and ablation approach solely using a manually controlled steerable sheath for catheter navigation improved the outcome of circumferential left atrial PV ablation at similar intervention times and similar complication rates. The 6‐month success rate after a single LA intervention increased from 56% to 77%.     

Clinical relevance and management of early recurrences after catheter ablation of atrial fibrillation

Evaluation of: Malasana G, Day JD, Weiss JP et al. A strategy of rapid cardioversion minimizes the significance of early recurrent atrial tachyarrhythmias after ablation for atrial fibrillation. J. Cardiovasc. Electrophysiol. DOI: 10.1111/j.1540–8167.2010.02005.x (2011) (Epub ahead of print).

Early recurrences of atrial arrhythmias are frequent and have been reported in up to 50% of patients after radiofrequency catheter ablation. As these arrhythmias do not definitively indicate therapy failure over the long term, this period is also referred to as the ‘blanking’ or ‘therapy stabilization’ period. Nevertheless, early recurrences have been linked to the occurrence of late recurrences after catheter ablation of atrial fibrillation. Treatment strategies aiming at these early recurrences range from conservative management to repeat catheter ablation with controversial results. In this article, we evaluate a recent publication investigating the efficacy of an aggressive rhythm control approach, with the use of prompt electrical cardioversion for early arrhythmia recurrences on long-term outcomes after atrial fibrillation ablation, and discuss the results in the light of current evidence.     

Quality-of-life in patients with paroxysmal atrial fibrillation after catheter ablation: results of long-term follow-up

Paroxysmal atrial fibrillation (PAF) significantly impairs patients' quality-of-life (QOL). The effect on QOL of recently developed ablation techniques with curative intention has not been studied. Thirty patients (21 men, age 54.1 +/- 9.5 years) with PAF (duration 5.6 +/- 5.2 years) who failed antiarrhythmic (3.8 +/- 1.2 trials) drug therapy underwent catheter ablation. The follow-up time was 33.9 +/- 11 months. QOL was assessed preablation, 3, 6, 9, 12, 24, and 36 months after catheter ablation. The Medical Outcomes Survey Short-Form (SF-36), scored on a 0-100 scale for each of eight domains: bodily pain, general health, mental health, physical functioning, role-emotional, role-physical, social functioning, and vitality, was used. Simultaneously, patients filled out a symptom-specific checklist (SSC) with seven clinical items scored 1-4 (1 best): dyspnea, nausea, palpitations, anxiety, syncope, presyncope, and NYHA classification. Patients with successful catheter ablation had a significant benefit in seven of eight subscales while patients with recurrence had an impact on QOL in two of eight subscales. Using SSC, a successful ablation influenced scores in all seven items while patients with recurrence had a significant change of clinical symptoms in only one item, anxiety. The subscales of the study group compared to a healthy population show higher scores after 24 months of follow-up. Patients with PAF experience a significant improvement in QOL after a successful catheter ablation. In contrast, in patients with recurrence of PAF the QOL showed improvement to a lesser extent and patients experienced ongoing symptoms.