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Background: Pre-excited atrial fibrillation (AF) is associated with increased risk of life-threatening events. However, at times, patients with pre-excited AF still repetitively suffer from hemodynamic disturbance, with resistance to acute treatments of antiarrhythmic therapy and cardioversion., Methods: To evaluate the feasibility in correcting hemodynamic disturbance, patients with pre-excited AF who underwent catheter ablation of accessory pathway as an emergency procedure, were retrospectively collected from two centers of China. The medical records of patients were analyzed and summarized in this case series., Results: Five patients with pre-excited AF who received emergency catheter ablation of accessory pathway, were collected from two contributor centers and reported in this case series. All collected patients still repetitively suffered from hemodynamic disturbance induced by rapid anterograde conduction of AF via pathway, even guideline recommended acute interventions of intravenous antiarrhythmic therapy and cardioversion had been performed. Finally, as an emergency procedure, catheter ablation of accessory pathway was performed in collected patients. Correspondingly, the hemodynamic unstable status was greatly relieved. Meanwhile, all collected patients with high risk of pre-excited AF were combined with left-sided accessory pathway, with shortest RR interval of widened pre-excited QRS complex less than 250 ms. Thus, combination with left-sided pathway is proposed as an indicator for the increased risk of life-threatening events in patients with high risk of pre-excited AF., Conclusions: Emergency catheter ablation of accessory pathway is an effective option for the acute managements of patients with high risk of pre-excited AF in unstable hemodynamics, which is resistant to antiarrhythmic therapy and cardioversion., (© 2022 Wiley Periodicals LLC.)

Objective: This study was performed to observe the effect of radiofrequency catheter ablation (RFCA) in patients with paroxysmal atrial fibrillation (PAF) and to explore the risk factors for late recurrence of atrial fibrillation (LRAF) after a single RFCA session., Methods: In this retrospective study, 243 patients with PAF underwent RFCA and were followed up regularly., Results: At a median follow-up of 37 months after a single procedure, 60.5% of patients maintained sinus rhythm (SR), and at a median follow-up of 42 months after multiple procedures, 74.9% of patients maintained SR. The statistically significant risk factors for LRAF after a single RFCA session were the left atrial diameter (LAD), left inferior pulmonary vein superior-inferior diameter (LIPV SID), PV number variation, circumferential pulmonary vein isolation (CPVI) combined with additional ablation, and early recurrence of atrial fibrillation (ERAF). The best cut-off value for LAD was 35.5 mm., Conclusions: During a 3-year follow-up, about 70% of the patients with PAF maintained SR. LRAF after a single procedure was associated with the LAD, LIPV SID, PV number variation, CPVI combined with additional ablation, and ERAF.

Background: The efficacy of short-term antiarrhythmic drugs (AADs) use compared with no-AADs prescription after catheter ablation of atrial fibrillation (AF) in preventing atrial arrhythmia recurrence is uncertain., Methods: We searched PubMed, Embase, and the Cochrane Library through December 2015 to identify randomized controlled trials (RCTs) which evaluated the efficacy of short-term AADs use compared with no-AADs prescription after AF ablation in preventing atrial arrhythmia recurrence. The primary outcome was labeled as early atrial arrhythmia recurrence within 3 months after ablation. Secondary outcome was defined as late recurrence after 3 months of ablation. Random-effects model or fixed-effects model was used to estimate relative risks (RRs) with 95% confidence intervals (CIs)., Results: Six RCTs with 2,667 patients were included into this meta-analysis. Compared with no-AADs administration after AF ablation, short-term AADs use was associated with significant reduction of early atrial arrhythmia recurrence (RR, 0.68; 95% CI, 0.52-0.87; p = 0.003). Trial sequential analysis (TSA) showed that the cumulative Z-curve crossed the trial sequential monitoring boundary for benefit, establishing sufficient and conclusive evidence. However, compared with no-AADs prescription, short-term AADs use after AF ablation didn't significantly reduce the risk of late atrial arrhythmia recurrence (RR, 0.92; 95% CI, 0.83-1.03; p = 0.15). TSA supported this result; meanwhile the estimated required information size (1,486 patients) was also met., Conclusion: Short-term use of AADs after AF ablation can significantly decrease the risk of early atrial arrhythmia recurrence but not lead to corresponding reduction in risk of late atrial arrhythmia recurrence.

The purpose of this study was to investigate whether atrial overexpression of angiotensin-converting enzyme 2 (ACE2) by homogeneous transmural atrial gene transfer can reverse atrial remodeling and its mechanisms in a canine atrial-pacing model. Twenty-eight mongrel dogs were randomly divided into four groups: Sham-operated, AF-control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP) and gene therapy with Ad-ACE2 (Ad-ACE2) (n = 7 per subgroup). AF was induced in all dogs except the Sham-operated group by rapid atrial pacing at 450 beats/min for 2 weeks. Ad-EGFP and Ad-ACE2 group then received epicardial gene painting. Three weeks after gene transfer, all animals except the Sham group underwent rapid atrial pacing for another 3 weeks and then invasive electrophysiological, histological and molecular studies. The Ad-ACE2 group showed an increased ACE2 and Angiotensin-(1-7) expression, and decreased Angiotensin II expression in comparison with Ad-EGFP and AF-control group. ACE2 overexpression attenuated rapid atrial pacing-induced increase in activated extracellular signal-regulated kinases and mitogen-activated protein kinases (MAPKs) levels, and decrease in MAPK phosphatase 1(MKP-1) level, resulting in attenuation of atrial fibrosis collagen protein markers and transforming growth factor-β1. Additionally, ACE2 overexpression also modulated the tachypacing-induced up-regulation of connexin 40, down-regulation of connexin 43 and Kv4.2, and significantly decreased the inducibility and duration of AF. ACE2 overexpression could shift the renin-angiotensin system balance towards the protective axis, attenuate cardiac fibrosis remodeling associated with up-regulation of MKP-1 and reduction of MAPKs activities, modulate tachypacing-induced ion channels and connexin remodeling, and subsequently reduce the inducibility and duration of AF.

It is controversial whether angiotensin II receptor blockers provide better protection than calcium antagonists against atrial fibrillation (AF) recurrence in hypertensive patients. This study was designed to compare the effect of nifedipine- and telmisartan-based antihypertensive treatments for preventing AF recurrence in hypertensive patients with paroxysmal AF. A total of 149 hypertensive patients with paroxysmal AF were randomized to nifedipine- or telmisartan-based antihypertensive treatment groups. The target blood pressure (BP) was <130/80 mm Hg. Clinic BP, ECG, Holter monitoring, and echocardiography were followed up for 2 years. The primary end point was the incidence of overall and persistent AF recurrence. During follow-up, there was no statistical difference in the rate of patients lowering to target BP between both groups, whereas nifedipine group had slightly better BP control but similar heart rate control at 24 months. The incidence of AF recurrence was similar in both groups (nifedipine versus telmisartan: 58.7% versus 55.4%; P=0.742), and Kaplan-Meier analysis showed no significant difference in the freedom from AF recurrence (log-rank test; P=0.48). However, the rate of developing persistent AF in telmisartan group was lower than that in nifedipine group (5.4% versus 16.0%; P=0.035). Patients in telmisartan group had lower values of left atrial diameter, left atrial volume index, and left ventricular mass index at the end of follow-up. The effects of telmisartan in preventing AF recurrences in hypertensive patients with paroxysmal AF after intensive lowering BP is similar to that of nifedipine, but telmisartan has more potent effects on preventing progression to persistent AF.

Background: To predict the recurrence of atrial fibrillation is important for selecting patients who will be undergoing catheter ablation, several studies respectively evaluated the risk factor of the recurrence of atrial fibrillation post-ablation., Objective: To investigate the factors predicting the recurrence of atrial fibrillation (AF) after catheter ablation., Methods: 186 patients (55.12 ± 12.06 years, 123 male) including 161 paroxysmal AF and 25 non-paroxysmal AF who underwent catheter ablation were studied. Clinical datum before and during ablation were recorded, and systematic follow-up was conducted after ablation. Univariate and multivariate analyses were carried out to determine the factors predicting late recurrence of AF (LRAF) which means AF recurrence after 3 months., Results: There were 47(25.27%) patients who experienced LRAF. Multivariate Logistic regression analysis was carried out to the parameters that P<0.10 in the univariate analysis, which includes overweight/obesity, metabolic syndrome (MetS), AF categories, duration of AF history, left atrial diameter (LAD), diabetes mellitus, ablation strategies, procedural failure and early recurrence of AF after ablation (ERAF). Ultimately, the results demonstrated that overweight/obesity (OR=4.71, 95% CI 1.71-12.98, P=0.003), MetS (OR=4.41, 95% CI 1.56-12.46, P=0.005), procedural failure (OR=58.34, 95% CI 6.83-498.34, P<0.001), and ERAF (OR=3.18, 95% CI 1.07-9.44, P=0.037) were independent predictors of AF recurrence after ablation., Conclusion: Overweight/obesity, metabolic syndrome, procedural failure and ERAF are independent predictors of late recurrence of atrial fibrillation in this group of patients., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Background: Previous studies reported that RAS inhibitors prevented atrial fibrillation by improving atrial electrical and structural remodeling. However, the effect of RAS inhibitors on the substrates of atrial fibrillation (AF) underlying hyperthyroid is unclear., Methods: Forty rabbits were assigned to four groups: sham group, thyroxine group, benazepril group and irbesartan group (10 per group). The atrial effective refractory period (AERP) was measured. The physiologic rate adaptation and the AF vulnerability were evaluated. The real-time PCR, Western blot or fluorescent immunohistochemistry was performed to detect the expression of AF related Ca+, K+ channel and gap junction., Results: No significant difference was found in AERP among the thyroxine group, benazepril group and irbesartan group (75.13±5.41ms vs. 76.63±4.44ms, 79±4.95ms, P=0.28). However, benazepril or irbesartan could reduce AF vulnerability underlying hyperthyroid (75% vs. 37%, 44%, for thyroxine group, benazepril group and irbesartan group, respectively), and significantly improved physiologic rate adaptation of the AERP. Furthermore, both drugs significantly reduced L-Ca(2+) channel related subunits (α1C or α1D) and interstitial fibrosis (17.1±2.2% vs. 12.3±1.8, 11.7±1.2%, P<0.01, for thyroxine group, benazepril group and irbesartan group, respectively), increased lateral/polar connection of Cx43 (1.04±0.16 vs. 1.33±0.29,1.28±0.25, P<0.01, for thyroxine group, benazepril group and irbesartan group, respectively) and improved the abnormal distribution of gap junctions (Cx40, Cx43) underlying hyperthyroid., Conclusion: Blockade of angiotensin II could improve abnormal atrial electrophysiological properties and further reduce AF vulnerability by extenuating ion channel, gap junction and structural remodeling in experimental thyrotoxic rabbits., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: Renin-angiotensin system (RAS) plays an important role in atrial fibrillation (AF). Recently, many publications have studied the associations between RAS-related gene polymorphisms and AF risk, with inconsistent results. To further evaluate these associations, we carried out a meta-analysis of all the published studies., Methods: Electronic searches were used to identify published studies evaluating RAS-related gene polymorphisms and AF risk before April 2009. We extracted data sets and performed meta-analysis with standardized methods., Results: A meta-analysis of 12 publications on association between angiotensin-converting enzyme (ACE insertion/deletion) and AF risk was performed. The pooled relative risk (RR) of allele D versus I was 1.19 (95% CI, 1.07-1.32, P < .01), pooled RR of DD and DI versus II was 1.31(95% CI, 1.09-1.58, P < .01) and 1.06 (95% CI, 0.97-1.16, P = .22) respectively. In subgroup analysis, a stronger association was found in hypertensive population, Western ethnic, lone AF, and patients aged > or = 65 years, with pooled RR of DD versus II was 1.74 (95% CI, 1.39-2.18, P < .01), 1.27 (95% CI, 1.01-1.59, P = .04), 1.53 (95% CI, 1.31-1.78, P < .01) and 1.38 (95% CI, 1.10-1.73, P < .01), respectively., Conclusion: The results suggested an association between ACE insertion/deletion and AF risk. More large-scale studies are warranted to document the conclusive evidence of the effects of the RAS genes on AF risk., (2010 Mosby, Inc. All rights reserved.)

Introduction: The effect of different treatment strategies of atrial fibrillation on left atrial (LA) size has not been compared in lone paroxysmal atrial fibrillation. The objective of the present study was to evaluate the evolution of LA size over time in patients who underwent different treatment interventions., Methods and Results: Two hundred forty patients with lone paroxysmal atrial fibrillation were assigned to four groups. The circumferential pulmonary vein ablation (CPVA) group (n = 60) was treated with CPVA, segmental pulmonary vein isolation (SPVI) group (n = 60) with SPVI, AMIO group (n = 60) with amiodarone alone, and AMIO + LO group (n = 60) with amiodarone plus losartan. LA diameter was measured with transthoracic echocardiogram at baseline, 3, 6, 9, and 12 months after the interventions. In the CPVA group, LA size at third, sixth, ninth, and 12th month had a significant decrease than that at baseline and in the other three groups. LA size in patients with atrial fibrillation recurrence in the four groups was significant higher than that in patients with no atrial fibrillation recurrence (P = 0.002-0.001)., Conclusion: The results suggested that a shortened LA size is not consistent with improved sinus rhythm maintenance. Although maintenance of sinus rhythm is not the only factor in determining shrinking or enlargement of the left atrium, inhibiting or eliminating activity of the pulmonary vein is very important for paroxysmal atrial fibrillation. Atrial fibrillation recurrence is a main factor contributing to enlargement of the LA.