Optimal endpoint for catheter ablation of longstanding persistent atrial fibrillation: A randomized clinical trial.

BACKGROUND: In longstanding persistent atrial fibrillation (LPeAF), the ideal endpoint of ablation remains to be determined. This study was to explore the value of pursuing AF termination or no with the same strategy during ablation on the long-term outcomes in patients with LPeAF. METHODS: Utilized "CCL" strategy is a fixed ablation approach consisting of circumferential pulmonary vein antrum isolation, ablation of complex fractionated atrial electrogram, and linear ablation between two anatomical structures (the mitral isthmus, left atrial roof). Note that 400 patients were randomized to group A (technical endpoint) and group B (pursuing AF termination). RESULTS: A group with technical endpoint had lower rate of acute AF termination (AF→sinus rhythm, 3.5% vs 18.1%; AF→atrial tachycardia, 23.7% vs 44.7%; P < 0.01) and shorter duration of ablation (164.9 ± 20.8 vs 223.4 ± 24.9, P < 0.01), radiofrequency delivery time (69.8 ± 18.1 vs 102.2 ± 26.3, P < 0.01), and x-ray exposure time (18.2 ± 8.8 vs 27.9 ± 12.4, P < 0.01) than those in B group (pursuing AF termination). During follow-up, freedom from atrial arrhythmias did not differ between the two groups after a single ablation procedure (46.5% vs 54.3%, P=0.12) and the final ablation procedure (60.1% vs 65.8%, P  =  0.24). CONCLUSION: In patients of LPeAF, pursuing AF termination during ablation was associated with similar long-term clinical outcome compared to that with technical endpoint. Ablation to termination is not the best strategy during ablation.

TRIF promotes angiotensin II-induced cross-talk between fibroblasts and macrophages in atrial fibrosis.

AIMS: Atrial fibroblasts and macrophages have long been thought to participate in atrial fibrillation (AF). However, which specific mediator may regulate the interaction between them remains unclear. METHODS AND RESULTS: We provided the evidence for the involvement of Toll/IL-1 receptor domain-containing adaptor inducing IFN-ß (TRIF), an important inflammation-related molecule, in the pathophysiology of AF. Patients with AF showed higher levels of angiotensin II (AngII) and TRIF expression and larger number of macrophages infiltration in left atria appendage than individuals with sinus rhythm (SR). In the cell study, AngII induced chemokines expressions in mouse atrial fibroblasts and AngII-stimulated atrial fibroblasts induced the chemotaxis of macrophages, which were reduced by losartan and TRIF siRNA. Meanwhile, AngII-stimulated atrial fibroblasts proliferation was enhanced by macrophages. CONCLUSIONS: Our data demonstrated that TRIF may be a crucial factor promoting the interaction between atrial fibroblasts and macrophages, leading to atrial fibrosis.

Discovery of TBX20 as a Novel Gene Underlying Atrial Fibrillation.

Atrial fibrillation (AF), the most prevalent type of sustained cardiac dysrhythmia globally, confers strikingly enhanced risks for cognitive dysfunction, stroke, chronic cardiac failure, and sudden cardiovascular demise. Aggregating studies underscore the crucial roles of inherited determinants in the occurrence and perpetuation of AF. However, due to conspicuous genetic heterogeneity, the inherited defects accounting for AF remain largely indefinite. Here, via whole-genome genotyping with genetic markers and a linkage assay in a family suffering from AF, a new AF-causative locus was located at human chromosome 7p14.2-p14.3, a ~4.89 cM (~4.43-Mb) interval between the markers D7S526 and D7S2250. An exome-wide sequencing assay unveiled that, at the defined locus, the mutation in the TBX20 gene, NM_001077653.2: c.695A>G; p.(His232Arg), was solely co-segregated with AF in the family. Additionally, a Sanger sequencing assay of TBX20 in another family suffering from AF uncovered a novel mutation, NM_001077653.2: c.862G>C; p.(Asp288His). Neither of the two mutations were observed in 600 unrelated control individuals. Functional investigations demonstrated that the two mutations both significantly reduced the transactivation of the target gene KCNH2 (a well-established AF-causing gene) and the ability to bind the promoter of KCNH2, while they had no effect on the nuclear distribution of TBX20. Conclusively, these findings reveal a new AF-causative locus at human chromosome 7p14.2-p14.3 and strongly indicate TBX20 as a novel AF-predisposing gene, shedding light on the mechanism underlying AF and suggesting clinical significance for the allele-specific treatment of AF patients.

Clinical Safety and Efficacy of Ablation for Atrial Fibrillation Patients With a History of Stroke.

Objectives: To evaluate the clinical safety and efficacy of radiofrequency catheter ablation for atrial fibrillation patients with a history of stroke. Methods and Results: A total of 116 symptomatic, drug-refractory AF patients with a history of stroke, and 1:2 matched patients without a history of stroke were enrolled. Of these, 28 cases occurred stroke within 3 months (Group 1), 88 cases with stroke history longer than 3 months (Group 2), and 232 cases without stroke (Group 3). PVI was performed in all patients, extended to ablation of linear lesions ablation. The periprocedural stroke rates and other procedure-related in-hospital complications did not differ significantly among the three groups. The maintenance rate of SR after the procedure showed no significant difference (p = 0.333), 52.7, 66.4, and 70.7% in Group 1, 2, and 3, respectively. Furthermore, the comparison between a history of stroke and those without it were also shown no significant difference (p = 0.351). Conclusions: Radiofrequency ablation for AF patients occurred stroke, even within 3 months is safe and effective, without higher periprocedural complication rate and recurrence rate.

A clinical study on the electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation.

BACKGROUND: The electrophysiological characteristics of patients without recurrence after ablation of persistent atrial fibrillation (AF) have not been systematically determined. This study compared the electrophysiological characteristics in patients with and without recurrence of AF after persistent AF ablation. METHODS: Forty-five patients without recurrence of AF after persistent AF ablation were enrolled to assess electrophysiological characteristics including pulmonary vein (PV) reconnection, the mitral isthmus (MI) line and the roof line reconduction. Ninety-five patients with recurrence of AF after ablation were used as the control group. RESULTS: Among patients without recurrence, recovery of PV conduction was observed in 37 of 45 (82.2%) patients: 3/45 (6.7%) reconnection in 4 veins, 7/45 (15.6%) in 3 veins, 11/45 (24.4%) in 2 veins, and 16/45 (35.6%) in 1 vein. No significant differences were seen in the proportion of patients with PV reconnection compared to patients with recurrence (p>0.05). Among patients without recurrence, the MI line reconduction was observed in 3/45 (6.7%) patients; the roof line conduction was observed in 5/45 (11.1%) patients. In comparison, patients with clinical recurrence of AF had recovery of the MI line conduction in 27/95 (28.4%) and recovery of the roof line conduction in 26/95 (27.4%). Significant differences were seen between these two groups (6.7% vs 28.4%, p=0.004; 11.1% vs 27.4%, p=0.031). CONCLUSION: Although a high incidence of PV reconnection was similarly observed in patients with and without recurrence of AF, a lower incidence of lines reconduction was observed in patients without recurrence of AF.

[Effect of zhigancao decoction containing serum on transient outward potassium current in isolated single ventricular myocyte of rabbits].

OBJECTIVE: To investigate the effect of Zhigancao Decoction (ZD) containing serum on transient outward potassium current (I(to)) in isolated single ventricular myocyte of rabbits. METHODS: Single rabbit ventricular myocytes were isolated and divided into 6 groups, the normal group, the non-drug-containing serum group, and the ZD groups, they were treated with normal extracellular fluid alone or with ZD containing serum recording technique was used to observe the changes of I(to). RESULTS: After treated with 5%, 10%, 20% and 40% ZD containing serum, the I(to) was inhibited and its peak value dropped from (16.1 +/- 1.4) PA/PF to (13.9 +/-1.5) PA/PF, (11.8 +/- 1.9) PA/PF, (8.3 +/- 1.5) PA/PF and (8.2 +/- 1.2) PA/PF respectively, and the effect could be eliminated by elution. CONCLUSION: ZD containing serum could inhibit the I(to) in isolated ventricular myocytes of rabbits in a concentration-dependent manner, which may be the mechanism of antiarrhythmic action of ZI).

Comparison of catheter ablation and surgical ablation in patients with long-standing persistent atrial fibrillation and rheumatic heart disease: a four-year follow-up study.

BACKGROUND: In our previous prospective and randomized study, we have demonstrated that the concomitant surgical ablation using saline-irrigated cooled tip radiofrequency ablation (SICTRA) system is more effective than subsequent circumferential pulmonary vein isolation (CPVI) combined with substrate modification in treating patients with long-standing persistent atrial fibrillation (LS-AF) and rheumatic heart disease (RHD) undergoing cardiac surgery during middle-term follow-up. Whether this strategy also decreases longer-term arrhythmia recurrence is unknown. This study describes the 4-year efficacy of SICTRA for these patients. Furthermore, we seek to compare the electrophysiological characteristics for recurrent atrial tachyarrhythmia (ATa) at the session of catheter ablation between two groups. METHODS: Long-term follow-up was performed in 95 patients who underwent the catheter ablation strategy (n=47, Group A) or SICTRA (n=48, Group B) combined with valvular surgery for symptomatic LS-AF patients with RHD. RESULTS: After one procedure, Group B had a significantly higher freedom from ATa compared with Group A (29/48 vs 15/47, P=0.005) after a mean follow-up of 54 months (range 48 to 63 months). Catheter-based mapping and ablation of recurrent ATa showed larger amounts of macro-reentrant atrial tachycardias (ATs) in Group B and higher incidence of pulmonary vein (PV) recovery in Group A. After multiple catheter ablations for recurrent ATa, sinus rhythm (SR) could be maintained equally between two groups. CONCLUSIONS: Single procedure success seems to be higher with SICTRA but repeated catheter ablation potentially results in comparable outcomes in treating patients with LS-AF and RHD during long-term follow-up. More macro-reentrant ATs and more PV recoveries are identified to be responsible for ATa in SICTRA and catheter ablation group, respectively.