Introduction: The safety and effectiveness of catheter ablation in patients with atrial fibrillation (AF) who underwent mechanical mitral valve replacement (MVR) have been reported. However, the impacts of different types of mitral valves on the safety and effectiveness of catheter ablation in patients with AF who underwent MVR have not been elucidated. Methods and results: From 2015 to 2021, 17,496 patients underwent catheter ablation of AF for the first time in Beijing Anzhen Hospital were screened. The inclusion criteria were (1) aged 18 years or older; (2) diagnosed with AF; (3) history of mitral valve replacement. The exclusion criteria were a history of catheter ablation, surgical maze procedure, left atrial appendage closure or resection. A total of 68 patients were enrolled in the study. The patients were divided into two groups: the bioprosthetic MVR group (n=12) and the mechanical MVR group(n=58). The size of the left atrial was larger (49.5mm vs. 46.0mm, p<0.05), the thickness of the left interventricular septum was larger (11.0mm vs. 10.0mm, p<0.05), and the mitral ring area was smaller (2.3mm2 vs. 2.6mm2, p<0.05) for the bioprosthetic MVR group than the mechanical MVR group. During 23.4 (6.1, 36.5) months of follow-up, the incidence of the endpoint events was not significantly different between the two groups (33.3% vs. 30.4%, log-rank p=0.48). There were 2 cases (3.4%) of pseudoaneurysm and 1 case of acute cerebral infarction in the mechanical MVR group. No complication was observed in the bioprosthetic MVR group. No significant clinical bleeding events were observed in the bioprosthetic group while eight patients in the mechanical MVR groups had bleeding events (p=0.368) during the follow-up. Conclusion: The safety and effectiveness of catheter ablation of AF were comparable between the patients with mechanical MVR and bioprosthetic MVR.

Background: CLBBB and AF are not uncommon coexisted. The impact of CLBBB on long-term prognosis of catheter ablation of AF has not been well determined. Objectives: This study aims to explore the long-term outcomes of patients with atrial fibrillation (AF) and complete left bundle branch block (CLBBB) after catheter ablation. Methods: Forty-two patients with CLBBB of the 11,752 patients who underwent catheter ablation of AF from 2011 to 2020 were enrolled as CLBBB group. After propensity score matching in a 1:4 ratio, 168 AF patients without CLBBB were enrolled as Non-CLBBB group. The primary endpoint was a composite of stroke, all-cause mortality, and cardiovascular hospitalization. The secondary endpoint was AF recurrence after single ablation. Results: The incidence of the primary endpoint in the CLBBB group was significantly higher than in the Non-CLBBB group (21.4% vs. 6.5%, HR 3.98, 95%CI 1.64-9.64, P = 0.002). The recurrence rates in the CLBBB group and the Non-CLBBB group were 54.8% and 31.5% (HR 1.71, 95%CI 1.04-2.79, P = 0.034), respectively. Multivariate analysis showed that CLBBB was an independent risk factor for both primary endpoint (HR 2.92, 95%CI 1.17-3.34, P = 0.022) and secondary endpoint (HR 2.19, 95%CI 1.09-4.40, P = 0.031) in patients with AF after catheter ablation. Conclusions: CLBBB significantly increased the risk of a composite endpoint of stroke, all-cause mortality, and cardiovascular hospitalization after catheter ablation in patients with AF. CLBBB also independently predicted recurrence in these patients.

Objective: To explore the safety and feasibility of left bundle branch area pacing (LBBAP) in children. Methods: This study observed 12 children attempted LBBAP from 2019 to 2021 in our department prospectively. Clinical data, pacing parameters, electrocardiograms, echocardiographic measurements and complications were recorded at implant and during follow-up. Results: The 12 patients aged between 3 and 14ys and weighted from 13 to 48kg. 11 patients were diagnosed with third-degree AVB and 1 patient (case 4) suffered from cardiac dysfunction due to right ventricular apical pacing (RVAP). LBBAP was successfully achieved in all patients with narrow QRS complexes. LVEF of case 4 recovered on the 3rd day after LBBAP. The median of LVEDD Z score of the 12 patients decreased from 1.75 to1.05 3 months after implantation (p<0.05). The median of paced QRS duration was 103ms. The median of pacing threshold, R-wave amplitude and impedance were 0.85V, 15mV and 717Ω respectively and remained stable during follow-up. No complications such as loss of capture, lead dislodgement or septal perforation occurred. Conclusions: LBBAP can be performed safely in children with narrow QRS duration and stable pacing parameters. Cardiac dysfunction caused by long-term RVAP can be corrected by LBBAP quickly.

Abstract Introduction: Linear ablation in addition to pulmonary vein antrum isolation (PVAI) has failed to improve the success rate for persistent atrial fibrillation (PeAF), due to incomplete block of ablation lines, especially in the mitral isthmus (MI). Methods and results: The study enrolled 191 patients (66 in group 1 and 125 in group 2). In group 1, EI-VOM was firstly performed, followed by radiofrequency (RF) applications targeting bilateral PVAI and bidirectional block in the roofline, cavotricuspid isthmus, and MI. In group 2, PVAI and the three linear ablations were completed using only RF energy. MI block was achieved in 63(95.5%) and 101(80.8%) patients in group 1 and 2, respectively (p=0.006). Patients in group 1 had shorter ablation time for left pulmonary vein antrum (8.15 min vs 12.59 min, p<0.001) and MI (7.0 min vs 11.8 min, p<0.001) and required less cardioversion (50(78.5%) vs 113(90.4%), p=0.007). During the 12-month follow-up, 58 (87.9%) patients were free from AF/AT in group 1 compared with 81 (64.8%) in group 2 (p<0.001). In multivariate cox regression, the ‘upgraded 2C3L’ procedure is associated with a lower recurrence rate (HR 0.27, 95%CI 0.12-0.59). Conclusion: Compared with the conventional ‘2C3L’ approach, the ‘upgraded 2C3L’ approach has higher effectiveness for ablation of PeAF.

Background: Atrial fibrillation (AF) is common in abdominal solid organ transplant recipients and a cause of morbidity and mortality in this population. However, the outcomes of catheter ablation (CA) in transplant recipients with AF remain unclear. This study aimed to elucidate the outcomes of CA in renal and hepatic transplant recipients. Methods and Results: Between 2015 and 2019, 14 transplant recipients (9 with kidney transplantation and 5 with liver transplantation) were enrolled from among 10,741 AF patients and underwent CA at Anzhen Hospital. Another 56 patients matched by age, sex and AF type were selected as the control group (4 controls for each transplant recipient). During a mean follow-up of 30.0±13.3 months after the initial procedure, 10 (71.4%) of the transplant patients, compared to 41 (73.2%) of the control patients, remained free from AF recurrence(P=1.000). A repeated procedure was performed in 1 transplant patient and in 6 control subjects. Consequently, 11 (78.6%) of the transplant patients, compared to 46 (82.1%) of controls, were in sinus rhythm after the repeated ablation (P=0.715). Notably, Kaplan–Meier analysis did not demonstrate any significant differences in the atrial arrhythmia-free rate after the initial and repeated procedure between the two groups. Vascular complications were identified in 1 transplant patient and 2 control subjects, while no life-threatening complications were observed in either group. There was no transient allograft dysfunction in transplant recipients after CA. Conclusion: CA is safe and effective in abdominal solid transplant recipients, and may be an optimal therapeutic strategy for this group.

Background Nodo-ventricular(NV) fiber-related reentrant tachycardias are so rare that most of them were reported by case, while few reports have summarized their common and individual features. Objectives To clarify the electrophysiological mechanism of supra-ventricular tachycardias (SVT) related to concealed NV fibers. Methods and Results We studied the intra-cardiac electrograms during electrophysiological study of 3 cases of SVT concerning concealed NV fibers. Maneuvers including ventricular entrainments, His bundle refractory period ventricular stimuli, adenosine triphosphate injection and so on were done for differential diagnosis before ablation. Among these patients, one had AVNRT with a bystander NV fiber, the other 2 had NV fiber-mediated orthodromic reentrant tachycardias (NVRT). VA dissociation were observed during SVT in all with antegrade His bundle conduction sequence. His bundle refractory period ventricular stimuli reset tachycardias with resetting of the H-H interval advancing the V-V interval, suggesting the existence of an accessory pathway. The cycle length of an NVRT prolonged during the status of functional right bundle branch block. Multiple QRS fusion morphologies during ventricular entrainments on a fixed site could be observed. Conclusions Concealed NV fibers can mediate orthodromic SVT or be a bystander of AVNRT. V-A dissociation usually occur during such SVTs. An NV fiber not only expresses the characteristics of an AP, but also the characteristics of the AV node. Multiple QRS fusion morphologies during ventricular entrainments or His bundle refractory period ventricular stimuli on a fixed site can discriminate NV fibers from NF fibers.