Aim To explore the impact of ablation termination on the maintenance of sinus rhythm in long-stand-ing persistent atrial fibrillation(LSPAF)by"Stepwise"ablation strategy.Methods This study involved 260 LSPAF patients who underwent"Stepwise"ablation strategy and clinical characteristics were collected.According to the ablation procedure,the patients were divided into ablation termination group and cardioversion group.The prognostic value of con-version to atrial flutter(AFL)and ablation termination was analyzed using subgroup analysis,followed up for 1 year to ex-plore their impact on prognosis.Results Overall,103(39.6％)cases of LSPAF were terminated by ablation.Compared to the cardioversion group,the courses of atrial fibrillation and left atrial diameter were lower in the ablation ter-mination group(all P＜0.05).At 1 year of follow-up,45(17.3％)patients had experienced recurrence,with no statis-tical difference in the proportion of recurrence between the two groups(all P＞0.05).Compared to preoperative,left atri-al diameter was significantly lower after 1 year regardless of recurrence.In subgroup analysis,conversion to AFL and ab-lation termination was associated with the maintenance of long-term sinus rhythm(all P＜0.05).On multivariable Cox re-gression,the courses of atrial fibrillation,body mass index,left atrial diameter and fasting blood glucose were independent risk factors for recurrence.Conclusions 39.6％of LSPAF recovered sinus rhythm during the"Stepwise"ablation process,but there was no correlation with long-term sinus rhythm maintenance.Termination of ablation after conversion to AFL during ablation has a predictive effect on the maintenance of long-term sinus rhythm.

Background::Oral anti-coagulants (OAC) are the intervention for the prevention of stroke, which consistently improve clinical outcomes and survival among patients with atrial fibrillation (AF). The main purpose of this study is to identify problems in OAC utilization among hospitalized patients with AF in China.Methods::Using data from the Improving Care for Cardiovascular Disease in China-Atrial Fibrillation (CCC-AF) registry, guideline-recommended OAC use in eligible patients was assessed.Results::A total of 52,530 patients with non-valvular AF were enrolled from February 2015 to December 2019, of whom 38,203 were at a high risk of stroke, 9717 were at a moderate risk, and 4610 were at a low risk. On admission, only 20.0% (6075/30,420) of patients with a diagnosed AF and a high risk of stroke were taking OAC. The use of pre-hospital OAC on admission was associated with a lower risk of new-onset ischemic stroke/transient ischemic attack among the diagnosed AF population (adjusted odds ratio: 0.54, 95% confidence interval: 0.43–0.68; P <0.001). At discharge, the prescription rate of OAC was 45.2% (16,757/37,087) in eligible patients with high stroke risk and 60.7% (2778/4578) in eligible patients with low stroke risk. OAC utilization in patients with high stroke risk on admission or at discharge both increased largely over time (all P <0.001). Multivariate analysis showed that OAC utilization at discharge was positively associated with in-hospital rhythm control strategies, including catheter ablation (adjusted odds ratio [OR] 11.63, 95% confidence interval [CI] 10.04–13.47; P <0.001), electronic cardioversion (adjusted OR 2.41, 95% CI 1.65–3.51; P <0.001), and anti-arrhythmic drug use (adjusted OR 1.45, 95% CI 1.38–1.53; P <0.001). Conclusions::In hospitals participated in the CCC-AF project, >70% of AF patients were at a high risk of stroke. Although poor performance on guideline-recommended OAC use was found in this study, over time the CCC-AF project has made progress in stroke prevention in the Chinese AF population.Registration::ClinicalTrials.gov, NCT02309398.

Objective:To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice.Methods:This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed.Results:A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up.Conclusions:MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

Objective::The long QT syndrome type 2 is caused by the loss-of-function mutations in the KCNH2 gene, which encodes hERG1, the voltage-gated potassium channel. The hERG1 channels conduct rapid delayed rectifier K + currents ( IKr) in the human cardiac tissue. KCNH2 encodes 2 main isoforms—hERG1a and hERG1b, which assemble to form the homomeric or heteromeric hERG1 channels. However, the functional characteristics of the heteromeric hERG1 channels in long QT syndrome type 2 are not clear. In this study, a novel mutation in the N-terminus of hERG1a (F129I) was identified in a proband of long QT syndrome type 2. The purpose of this study was to identify the electrophysiological change of homomeric and heteromeric hERG1 channels with the F129I-hERG1a. Methods::Candidate genes were screened by direct sequencing. F129I-hERG1a was cloned in the pcDNA3.1 vector by site-directed mutagenesis. Then, the wild-type (WT) hERG1a and/or F129I-hERG1a were transiently expressed in the HEK293 cells with or without hERG1b co-expression. The expression levels of the transgenes, cellular distribution of hERG1a and hERG1b, and the electrophysiological features of the homomeric and the heteromeric hERG1 channels with the WT-hERG1a or F129I-hERG1a were analyzed using whole-cell patch-clamp electrophysiology, western blotting, and immunofluorescence techniques.Results::The proband was clinically diagnosed with long QT syndrome type 2 and carried a heterozygous mutation c.385T>A (F129I) in the KCNH2 gene. Electrophysiology study proved that the F129I substitution in hERG1a significantly decreased IKr in both the homomeric and heteromeric hERG1channels by 86% and 70%, respectively (WT-hERG1a (54.88 ± 18.74) pA/pF vs. F129I-hERG1a (7.34 ± 1.90) pA/pF, P < 0.001; WT-hERG1a/hERG1b (89.92 ± 24.51) pA/pF vs. F129I-hERG1a/hERG1b (26.54 ± 9.83) pA/pF, P < 0.001). The voltage dependence of I Kr activation (V ? and k) was not affected by the mutation in both the homomeric and heteromeric hERG1 channels. The peak current densities and the kinetic characteristics of I Kr were comparable for both WT/F129I-hERG1a and WT-hERG1a. The channel inactivation and deactivation analysis showed that F129I substitution did not affect deactivation of the homomeric hERG1a channel, but significantly accelerated the deactivation and recovery from inactivation of the heteromeric hERG1a/hERG1b channel based on the time constants of fast and slow recovery from deactivation F129I-hERG1a/hERG1b vs. WT-hERG1a/hERG1b ( P < 0.05). Western blotting and immunofluorescence labeling experiments showed that maturation and intracellular trafficking of the F129I-hERG1a protein was impaired and potentially increased the ratio of hERG1b to hERG1a in the F129I-hERG1a/hERG1b tetramer channel, thereby resulting in electrophysiological changes characteristic of the long QT syndrome type 2 pathology. Conclusions::IKr was significantly reduced in the homomeric and heteromeric hERG1 channels with F129I-hERG1a. The F129I mutation significantly accelerated the deactivation and recovery from inactivation of the heteromeric F129I-hERG1a/hERG1b channel. F129I-hERG1a exhibited impaired maturation and intracellular trafficking, thereby potentially increasing the ratio of the hERG1b to hERG1a stoichiometry in the hERG1 tetrameric channel. These changes demonstrated the importance of the heteromeric hERG1 channel in long QT syndrome type 2 pathophysiology.

Objective::The long QT syndrome type 2 is caused by the loss-of-function mutations in the KCNH2 gene, which encodes hERG1, the voltage-gated potassium channel. The hERG1 channels conduct rapid delayed rectifier K + currents ( IKr) in the human cardiac tissue. KCNH2 encodes 2 main isoforms—hERG1a and hERG1b, which assemble to form the homomeric or heteromeric hERG1 channels. However, the functional characteristics of the heteromeric hERG1 channels in long QT syndrome type 2 are not clear. In this study, a novel mutation in the N-terminus of hERG1a (F129I) was identified in a proband of long QT syndrome type 2. The purpose of this study was to identify the electrophysiological change of homomeric and heteromeric hERG1 channels with the F129I-hERG1a. Methods::Candidate genes were screened by direct sequencing. F129I-hERG1a was cloned in the pcDNA3.1 vector by site-directed mutagenesis. Then, the wild-type (WT) hERG1a and/or F129I-hERG1a were transiently expressed in the HEK293 cells with or without hERG1b co-expression. The expression levels of the transgenes, cellular distribution of hERG1a and hERG1b, and the electrophysiological features of the homomeric and the heteromeric hERG1 channels with the WT-hERG1a or F129I-hERG1a were analyzed using whole-cell patch-clamp electrophysiology, western blotting, and immunofluorescence techniques.Results::The proband was clinically diagnosed with long QT syndrome type 2 and carried a heterozygous mutation c.385T>A (F129I) in the KCNH2 gene. Electrophysiology study proved that the F129I substitution in hERG1a significantly decreased IKr in both the homomeric and heteromeric hERG1channels by 86% and 70%, respectively (WT-hERG1a (54.88 ± 18.74) pA/pF vs. F129I-hERG1a (7.34 ± 1.90) pA/pF, P < 0.001; WT-hERG1a/hERG1b (89.92 ± 24.51) pA/pF vs. F129I-hERG1a/hERG1b (26.54 ± 9.83) pA/pF, P < 0.001). The voltage dependence of I Kr activation (V ? and k) was not affected by the mutation in both the homomeric and heteromeric hERG1 channels. The peak current densities and the kinetic characteristics of I Kr were comparable for both WT/F129I-hERG1a and WT-hERG1a. The channel inactivation and deactivation analysis showed that F129I substitution did not affect deactivation of the homomeric hERG1a channel, but significantly accelerated the deactivation and recovery from inactivation of the heteromeric hERG1a/hERG1b channel based on the time constants of fast and slow recovery from deactivation F129I-hERG1a/hERG1b vs. WT-hERG1a/hERG1b ( P < 0.05). Western blotting and immunofluorescence labeling experiments showed that maturation and intracellular trafficking of the F129I-hERG1a protein was impaired and potentially increased the ratio of hERG1b to hERG1a in the F129I-hERG1a/hERG1b tetramer channel, thereby resulting in electrophysiological changes characteristic of the long QT syndrome type 2 pathology. Conclusions::IKr was significantly reduced in the homomeric and heteromeric hERG1 channels with F129I-hERG1a. The F129I mutation significantly accelerated the deactivation and recovery from inactivation of the heteromeric F129I-hERG1a/hERG1b channel. F129I-hERG1a exhibited impaired maturation and intracellular trafficking, thereby potentially increasing the ratio of the hERG1b to hERG1a stoichiometry in the hERG1 tetrameric channel. These changes demonstrated the importance of the heteromeric hERG1 channel in long QT syndrome type 2 pathophysiology.

BACKGROUND: The age, biomarkers, and clinical history (ABC)-atrial fibrillation (AF)-Stroke score have been proposed to refine stroke risk stratification, beyond what clinical risk scores such as the CHA2DS2-VASc score can offer. This study aimed to identify risk factors associated with thromboembolism and evaluate the performance of the ABC-AF-Stroke score in predicting thromboembolism in non-anticoagulated AF patients following successful ablations. METHODS: A total of 2692 patients who underwent successful ablations with discontinued anticoagulation after a 3-month blanking period in the Chinese Atrial Fibrillation Registry (CAFR) between 2013 and 2019 were included. Cox regression analysis was conducted to present the association of risk factors with thromboembolism risk. The ABC-AF-Stroke score was evaluated in terms of discrimination, including concordance index (C-index), net reclassification improvement (NRI) and integrated discrimination improvement (IDI), clinical utilization by decision curve analysis (DCA), and calibration by comparing the predicted risk with the observed annualized event rate. RESULTS: After a median follow-up of 3.5 years, 64 patients experienced thromboembolism events. Age, prior history of stroke/transient ischemic attack (TIA), high-sensitivity cardiac troponin T (cTnT-hs), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were independently associated with thromboembolism risk. The ABC-AF-Stroke score performed statistically significantly better than the CHA2DS2-VASc score in terms of C-index (0.67, 95% confidence interval [CI]: 0.59-0.74 vs. 0.60, 95% CI: 0.52-0.67, P = 0.030) and reclassification capacity. The DCA implied that the ABC-AF-Stroke score could identify more thromboembolism events without increasing the false positive rate compared to the CHA2DS2-VASc score. The calibration curve showed that the ABC-AF-Stroke score was well calibrated in this population. CONCLUSIONS In this real-world study enrolling non-anticoagulated AF patients following successful ablations, age, prior history of stroke/TIA, level of NT-proBNP, and cTnT-hs were independently associated with an increased risk of thromboembolism. The ABC-AF-Stroke score was well-calibrated and statistically significantly outperformed the CHA2DS2-VASc score in predicting thromboembolism risk.
Humans ; Anticoagulants/therapeutic use* ; Atrial Fibrillation/complications* ; East Asian People ; Ischemic Attack, Transient ; Registries ; Risk Assessment ; Risk Factors ; Stroke/etiology* ; Thromboembolism/etiology* ; Troponin T

Objectives:To explore the correlation between mitral annulus calcification(MAC)and recurrence of atrial fibrillation(AF)after radiofrequency ablation. Methods:The study included 785 patients with AF who underwent radiofrequency ablation in Beijing Anzhen Hospital from January 1,2019 to December 31,2020.According to the recurrence of AF after operation,patients were divided into recurrence group and non-recurrence group.Univariate Cox regression model was used to analyze the risk factors associated with AF recurrence,and multivariate Cox regression model was used to evaluate the influence of MAC on AF recurrence. Results:The average follow-up was(16±10)months.190 patients(24.2%)in the recurrence group,595(75.8%)patients in the non-recurrence.Patients in the recurrence group were older,had a higher proportion non-paroxysmal AF,a higher proportion of MAC,moderate/severe mitral regurgitation and larger left atrial diameter(LAD),and higher CHA2DS2-VASc score(all P<0.001).Univariate analysis showed that MAC was a risk factor of AF recurrence after radiofrequency ablation(HR=2.530,95%CI:1.639-3.907,P<0.001).After adjusting for age and sex,MAC remained significantly associated with an increased risk of AF recurrence after radiofrequency ablation(HR=1.52,95%CI:1.14-2.17,P<0.001).After multivariate adjustment for age,sex,non-paroxysmal AF,hypertension,diabetes,LAD,moderate/severe mitral regurgitation,and CHA2DS2-VASc score,MAC remained as an independent risk factor of AF recurrence(HR=1.48,95%CI:1.13-1.95,P=0.001). Conclusions:MAC is significantly associated with an increased risk of AF recurrence after radiofrequency ablation.

Objective:To investigate the long-term safety of digoxin in patients with coronary artery disease (CAD) and atrial fibrillation (AF).Methods:This was a prospective study, in which 25 512 AF patients were enrolled from China Atrial Fibrillation Registry Study. After exclusion of patients receiving ablation therapy at the enrollment, 1 810 CAD patients [age: (71.5±9.3)years] with AF were included. The subjects were grouped into the digoxin group and non-digoxin group, and were followed up for a period of 80 months. Long-term outcomes were compared between the groups and an adjusted Cox regression analysis was applied to evaluate the risk of digoxin on the long-term outcomes. The primary endpoint was all-cause mortality.Results:The patients were followed up for a median period of 3.05 years. After multivariable adjustment, the Cox regression analysis showed that digoxin significantly increased the risk of all-cause mortality ( HR=1.28, 95% CI 1.01-1.61, P=0.038), cardiovascular mortality ( HR=1.48,95% CI 1.10-2.00, P=0.010), cardiovascular hospitalization ( HR=1.67,95% CI 1.35-2.07, P=0.008) and the composite endpoints ( HR=2.02,95% CI 1.71-2.38, P<0.001). In the subgroup of patients with heart failure (HF), digoxin was not associated with the risk of all-cause mortality, but was still associated with the increased risk of cardiovascular mortality ( HR=1.44,95% CI 1.05-1.98, P=0.025), cardiovascular hospitalization ( HR=1.44,95% CI 1.09-1.90, P=0.010) and the composite endpoints ( HR=1.37, 95% CI 1.01-1.70, P=0.004). However, in the subgroup of patients without HF, digoxin was only associated with all-cause mortality ( HR=2.56,95% CI 1.44-4.54, P=0.001). Conclusion:Digoxin significantly increased the risk of all-cause mortality in CAD patients with AF, especially in patients without HF.

Objective::Previous studies indicated that patients with atrial fibrillation (AF) and moderate-to-severe chronic kidney disease (CKD) are at a higher risk of thromboembolism and bleeding during anticoagulation. Whether mild CKD is associated with an increased risk of thromboembolism and bleeding in AF patients remains unknown. This study aimed to evaluate the impact of mild CKD on thromboembolism and major bleeding among patients with AF.Methods::Baseline serum creatinine was available in 17,559 of 25,512 patients enrolled in the China-AF study between August 2011 and December 2018. After excluding those who underwent AF ablation or with moderate-to-severe CKD, 7191 non-valvular AF patients (2059 with mild CKD and 5132 with normal renal function) with regular follow-up for at least 6 months were included. Primary outcomes were the time to the first occurrence of thromboembolic and major bleeding events.Results::Over a mean follow-up of (44.4 ± 23.4) months, 639 thromboembolism and 231 major bleeding events occurred. The crude incidence rates of thromboembolism were higher in the mild CKD group than that of the normal renal function group (3.0/100 person-years vs. 2.2/100 person-years, P < 0.0001), while the crude incidence rates of major bleeding were comparable between the two groups (1.0/100 person-years vs. 0.8/100 person-years, P= 0.076). After multivariate analyses, mild CKD was not associated with an increased risk of thromboembolism (HR = 1.05, 95% CI: 0.89-1.25, P= 0.547) or major bleeding (HR = 1.11, 95% CI: 0.84-1.47, P= 0.476). Conclusions::Mild CKD was not an independent risk factor of thromboembolism or major bleeding in patients with AF.

The feasibility and safety of intracardiac echocardiography (ICE)-guided catheter ablation for atrial fibrillation (AF) using a minimal/zero-fluoroscopy approach have recently been reported. This approach helps to reduce ionizing radiation exposure and orthopedic complications resulting from using lead aprons. The objectives of this planned prospective, multicenter randomized controlled trial (RCT) (paroxysmal AF (PAF)-ICE trial; ChiCTR2000033624) are to evaluate the efficacy and safety of ICE-guided minimal-fluoroscopy ablation in patients with PAF and the impact on occupational hazards among lab staff.Patients will be randomized in a 1:1 ratio to 2 groups: minimal fluoroscopy group ( n = 216) and traditional approach group ( n = 216). In the minimal fluoroscopy group, an ICE catheter will be used for geometry/anatomic construction, transseptal puncture, catheter tracking, and effusion monitoring. Pulmonary vein isolation (PVI) will be performed using an open-irrigated radiofrequency SmartTouch Surround Flow or SmartTouch catheter (Biosense Webster, Diamond Bar, California, USA), and confirmed by a multipolar Lasso or PentaRay catheter (Biosense Webster). In the traditional approach group, an ICE catheter will not be used. Transseptal puncture will be performed under fluoroscopic guidance, with all geometries constructed by mapping the catheters. The primary efficacy endpoint is freedom from AF recurrence (without antiarrhythmic medications) at 12 months after ablation. Other endpoints include duration of lead apron use, measures of intra-procedural efficiency, and peri-procedural complications. This RCT will evaluate the efficacy and safety of ICE-guided minimal-fluoroscopy ablation in patients with PAF, also evaluate the benefits to lab staff (regarding reducing occupational hazards) related to this "minimal/zero-fluoroscopy" and "leadless" mode.