Metagenomic data-analysis reveals enrichment of lipopolysaccharide synthesis in the gut microbiota of atrial fibrillation patients / 中华心血管病杂志

Objective: To investigate the functional changes of key gut microbiota (GM) that produce lipopolysaccharide (LPS) in atrial fibrillation (AF) patients and to explore their potential role in the pathogenesis of AF. Methods: This was a prospective cross-sectional study. Patients with AF admitted to Beijing Chaoyang Hospital of Capital Medical University were enrolled from March 2016 to December 2018. Subjects with matched genetic backgrounds undergoing physical examination during the same period were selected as controls. Clinical baseline data and fecal samples were collected. Bacterial DNA was extracted and metagenomic sequencing was performed by using Illumina Novaseq. Based on metagenomic data, the relative abundances of KEGG Orthology (KO), enzymatic genes and species that harbored enzymatic genes were acquired. The key features were selected via the least absolute shrinkage and selection operator (LASSO) analysis. The role of GM-derived LPS biosynthetic feature in the development of AF was assessed by receiver operating characteristic (ROC) curve, partial least squares structural equation modeling (PLS-SEM) and logistic regression analysis. Results: Fifty nonvalvular AF patients (mean age: 66.0 (57.0, 71.3), 32 males(64%)) were enrolled as AF group. Fifty individuals (mean age 55.0 (50.5, 57.5), 41 males(82%)) were recruited as controls. Compared with the controls, AF patients showed a marked difference in the GM genes underlying LPS-biosynthesis, including 20 potential LPS-synthesis KO, 7 LPS-biosynthesis enzymatic genes and 89 species that were assigned as taxa harbored nine LPS-enzymatic genes. LASSO regression analysis showed that 5 KO, 3 enzymatic genes and 9 species could be selected to construct the KO, enzyme and species scoring system. Genes enriched in AF group included 2 KO (K02851 and K00972), 3 enzymatic genes (LpxH, LpxC and LpxK) and 7 species (Intestinibacter bartlettii、Ruminococcus sp. JC304、Coprococcus catus、uncultured Eubacterium sp.、Eubacterium sp. CAG:251、Anaerostipes hadrus、Dorea longicatena). ROC curve analysis revealed the predictive capacity of differential GM-derived LPS signatures to distinguish AF patients in terms of above KO, enzymatic and species scores: area under curve (AUC)=0.957, 95%CI: 0.918-0.995, AUC=0.940, 95%CI 0.889-0.991, AUC=0.972, 95%CI 0.948-0.997. PLS-SEM showed that changes in lipopolysaccharide-producing bacteria could be involved in the pathogenesis of AF. The key KO mediated 35.17% of the total effect of key bacteria on AF. After incorporating the clinical factors of AF, the KO score was positively associated with the significantly increased risk of AF (OR<0.001, 95%CI:<0.001-0.021, P<0.001). Conclusion: Microbes involved in LPS synthesis are enriched in the gut of AF patients, accompanied with up-regulated LPS synthesis function by encoding the LPS-enzymatic biosynthesis gene.

Isolation of Fusarium and identification of its toxins from tuberous root of Pseudostellaria heterophylla / 中国中药杂志

Fusarium is the major pathogen of root rot of Pseudostellaria heterophylla. This study aims to explain the possible distribution of Fusarium species and the contamination of its toxin-chemotypes in tuberous root of P. heterophylla. A total of 89 strains of fungi were isolated from the tuberous root of P. heterophylla. Among them, 29 strains were identified as Fusarium by ITS2 sequence, accounting for 32.5%. They were identified as five species of F. avenaceum, F. tricinctum, F. fujikuroi, F. oxysporum, and F. graminearum based on β-Tubulin and EF-1α genes. LC-MS/MS detected 18, 1, and 5 strains able to produce ZEN, DON, and T2, which accounted for 62.1%, 3.4%, and 17.2%, respectively. Strain JK3-3 can produce ZEN, DON, and T2, while strains BH1-4-1, BH6-5, and BH16-2 can produce ZEN and T2. PCR detected six key synthase genes of Tri1, Tri7, Tri8, Tri13, PKS14, and PKS13 in strain JK3-3, which synthesized three toxins of ZEN, DON, and T2. Four key synthase genes of Tri8, Tri13, PKS14, and PKS13 were detected in strains BH1-4-1, BH6-5, and BH16-2, which were responsible for the synthesis of ZEN and T2. The results showed that the key genes of toxin biosynthesis were highly correlated with the toxins produced by Fusarium, and the biosynthesis of toxin was strictly controlled by the genetic information of the strain. This study provides a data basis for the targeted prevention and control of exo-genous mycotoxins in P. heterophylla and a possibility for the development of PCR for rapid detection of toxin contamination.

Transient ST-segment elevation after transseptal puncture for atrial fibrillation ablation in two cases / 中华医学杂志(英文版)

The present report demonstrates two cases of transient inferior ST-segment elevation accompanied by profound hypotension and bradycardia immediately after transseptal puncture for catheter ablation of atrial fibrillation. This rare complication of transseptal puncture was resolved quickly within several minutes. The most likely mechanism of this phenomenon is coronary vasospasm, although coronary embolism can not be ruled out completely. This complication is characterized as follows: (1) The right coronary artery might be the most likely involved vessel and therefore myocardial ischemia usually occurs in the inferior wall of left ventricular; (2) Reflex hypotension and bradycardia by the Bezold-Jarisch reflex secondary to inferior ischemia often occur at the same time. Though it appears to be a transient and completely reversible phenomenon, there are still potential life-threatening risks because of myocardial ischemia and profound haemodynamic instability. Clinical cardiologists should be aware of this rare complication and properly deal with it.

Catheter ablation of persistent atrial fibrillation with and without a history of paroxysmal atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>It is unclear whether a history of paroxysmal atrial fibrillation (PAF) would impact the effect of catheter ablation on persistent atrial fibrillation (AF). This study aimed to compare the effect of catheter ablation on persistent AF with and without a history of PAF.</p><p><b>METHODS</b>One hundred and eighty-three patients underwent catheter ablation of persistent AF lasting for > 1 month and were reviewed. Patients were divided into two groups according to whether they had a history of PAF or not. Group I consisted of persistent AF patients with a history of PAF, and group II consisted of persistent AF patients without such a history. All patients received catheter ablation focused on pulmonary vein isolation and were observed for arrhythmia recurrences, which were defined as documented episodes of AF or atrial tachycardia after a blanking period of 3 months.</p><p><b>RESULTS</b>One hundred and three patients (60.9%) in group I and sixty-six patients (39.1%) in group II were successfully followed and included in analysis. There were no significant differences in clinical and echocardiographic characteristics between both groups except for a younger age and more male patients in group II. After (15.5 ± 10.7) months of follow-up, 59 (57.3%) patients in group I and 49 (74.2%) patients in group II maintained sinus rhythm free of anti-arrhythmia drugs (P = 0.025). Multivariate analyses found left atrial anteroposterior diameter (P = 0.006) and persistent AF with a history of PAF (OR 1.792, 95%CI 1.019 - 3.152; P = 0.043) as the only independent statistical predictors of arrhythmia recurrences.</p><p><b>CONCLUSION</b>The arrhythmia recurrence rate of catheter ablation based on pulmonary vein isolation in persistent AF with a history of PAF was higher than those without a history of PAF.</p>

Epicardial isolation of pulmonary veins with ethanol in open chest dogs / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Radiofrequency (RF) ablation has become a widely accepted treatment for atrial fibrillation (AF). This study aimed to identify the efficacy and safety of pulmonary vein (PV) ablation with ethanol and to explore an alternative energy source for catheter ablation of AF.</p><p><b>METHODS</b>Twelve open-chest mongrel dogs were randomized into ethanol ablation group and control group. Both the injections and electrophysiological mapping procedures were performed epicardialy. In ethanol ablation group (n = 6), injections were performed to circumferentially ablate the root of each PV (0.2 ml each site, 3 mm apart) with 95% ethanol using an 1 ml injector. In control group (n = 6), saline was injected other than ethanol. PV isolation was confirmed with a circular catheter immediately after the procedure and at follow up of 30 days. PV isolation was defined as the absence of PV potentials at each electrode of the circular catheter positioned at the PV side of the lesions, as well as complete conduction block into left atrium (LA) during PV pacing.</p><p><b>RESULTS</b>PV electrical isolation with complete bidirectional conduction block was achieved with ethanol immediately and at 30 days in 95% of PVs, while saline injection caused only transient conduction changes between LA and PVs. In ethanol group, histologic analysis showed transmural lesions at 30 days. And there was no evidence of PV stenosis or thrombus formation. Mean LA diameter was not significantly different between baseline and 30 days.</p><p><b>CONCLUSION</b>Ethanol is a safe energy source to effectively isolate PV in canine model and may be promising in endocardial ablation procedure of AF patients in the future.</p>

Mitral isthmus ablation in patients with prosthetic mitral valves / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Previous studies have investigated the technique of linear ablation at the mitral isthmus (MI) in patients with idopathic atrial fibrillation (AF), but MI ablation in patients with prosthetic natural mitral valves (MVs) was not described in detail. Present study sought to summarize our initial experience of ablating MI in patients with prosthetic MVs</p><p><b>METHODS</b>Patients with drug refractory AF and prosthetic MVs were eligible for this study, and the patients with natural MVs but received MI ablation served as control group. Left atrium (LA) mapping and ablation was carried out guided by CARTO system. The anatomy of MI was assessed via computer topography scan.</p><p><b>RESULTS</b>During the study period, a consecutive of 19 patients (male/female = 12/7, mean age of (48 ± 6) years) with prosthetic MVs (16 with metal valves, 3 with biologic valves) entered for AF ablation, other 35 patients served as control group. In study group, mapping along MI documented lower voltages ((2.0 ± 1.0) vs. (3.1 ± 1.3) mV, P = 0.002), more fragmented potentials (19/19 vs. 20/15, P < 0.001), and higher impedance ((132 ± 34) vs. (110 ± 20) Ω, P = 0.004). After initial ablation, more residual gaps along the MI lesions were found in study group (2.4 ± 0.4 vs. 1.7 ± 0.3, P < 0.001). The mean length of MI ((6.2 ± 3.3) vs. (7.1 ± 2.3) cm, P = 0.25) was comparable between 2 groups, but the MI in study group was much thicker ((3.1 ± 1.8) vs. (2.1 ± 1.07) cm, P = 0.01) and all were found as pouch type (19/19 vs. 2/35, P < 0.001). The follow-up results were comparable (65.1% vs. 72.3%, P = 0.30).</p><p><b>CONCLUSION</b>For patients with prosthetic MVs, linear ablation at MI could be successfully carried out despite anatomical and pathological changes.</p>

Mechanisms of organized atrial tachycardia during catheter ablation of chronic atrial fibrillation by stepwise approach / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Extensive atrial fibrillation (AF) ablation is associated with an increased success rate of catheter ablation in chronic AF patients and an increased rate of atrial tachycardia (AT) during the procedure. The mechanism of these ATs varies in previous studies. Our study aimed to report the mechanism of organized AT occurring during the stepwise ablation procedure of chronic AF.</p><p><b>METHODS</b>A prospective cohort of 86 consecutive patients who underwent an ablation procedure for chronic atrial fibrillation (CAF) was investigated. The stepwise procedure was performed in the following order: circumferential pulmonary vein ablation, complex fractionated atrial electrograms ablation, mapping and ablation of AT. The endpoint was noninducibility of AF/AT after sinus rhythm (SR) was restored or the procedure time was beyond 6 hours.</p><p><b>RESULTS</b>Sixty-nine (80%) of patients converted to SR via AT. A total of 179 sustained ATs were observed in 69 patients during the procedure. There were 81% (n = 145) macroreentrant ATs which included 65 perimitral circuits, 48 peritricuspid tachycardia and 32 roof dependent circuits, 12% (n = 21) localized reentrant and 7% (n = 13) focal ATs. Thirty (15%) patients experienced significant left atrium (LA) and LA appendage (LAA) conduction delay or dissociation in the procedure or during the follow-up period.</p><p><b>CONCLUSIONS</b>Most CAF patients converted to SR via ablation of organized AT occurring during the stepwise procedure. The mechanism of most of these ATs was macro-reentry.</p>

Sinus node, phrenic nerve and electrical connections between superior vena cava and right atrium: lessons learned from a prospective study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>When performing superior vena cava isolation, the major concerns are inadvertent ablation on sinus node and right phrenic nerve. However, little is known about the spatial relationship of electrical connections between superior vena cava and right atrium with the sinus node and phrenic nerve locations among individual patients.</p><p><b>METHODS</b>We studied 87 patients (male/female 60/27, mean age of (51 +/- 9) years) with atrial fibrillation. Before superior vena cava isolation, the sinus node site was defined by right atrium activation mapping during sinus rhythm and the right phrenic nerve site was localized via pacing manoeuvre. Superior vena cava was isolated by ablation at the electrical connection under the guidance of circular mapping catheter. The sites of sinus node, phrenic nerve and electrical connections were noted. Continuous variables were compared using Student's t test. A P value < 0.05 was considered statistically significant.</p><p><b>RESULTS</b>Right atrium activation mapping revealed that the sinus node located at the anterior lateral segment of superior vena cava-right atrium junction in all patients. In 82 patients with detectable diaphragmatic stimulations, the phrenic nerve sites were predominantly at the lateral segment (70/82) with anterior lateral and anterior segments for a few patients. A total of 165 electrical connections were located among all 87 patients, and this averaged 1.8 +/- 0.6 (1-3) per patient. The anterior septum (72 patients (43.6%)), the anterior wall (40 (24.2%)), and the posterior septum (35 (35.4%)) of superior vena cava-right atrium junction were the electrical connection regular sites. Superior vena cava was isolated in all patients. Two patients developed sinus bradycardia, with 3 mild superior vena cava stenosis and 2 phrenic nerve palsy.</p><p><b>CONCLUSIONS</b>The sinus node, phrenic nerve and electrical connection sites were distributed along the superior vena cava-right atrium junctions at expected locations for most patients. The electrical connections were separated from the sinus node and phrenic nerve sites. With the activation mapping of right atrium and pacing along superior vena cava-right atrium junctions, the sinus node and phrenic nerve were localized and superior vena cava isolated in most patients.</p>

Metabolic syndrome in patients with atrial fibrillation in the absence of structural heart disease from a tertiary hospital in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Metabolic syndrome (MetS) and atrial fibrillation (AF) are causally related. This study aimed to determine the prevalence of MetS in patients with AF in the absence of structural heart disease from a tertiary hospital in China.</p><p><b>METHODS</b>In a single center, 741 inpatients with AF in the absence of structural heart disease prior to catheter ablation were retrospectively reviewed. Among them, 588 (79.4%) patients had paroxysmal AF. Subgroup analyses were performed in paroxysmal AF and persistent/permanent AF.</p><p><b>RESULTS</b>MetS was found in 343 (46.3%) patients (200 males, 143 females); 0, 1, 2, 3, 4, 5 components of the MetS were found in 59 (8.0%), 140 (18.9%), 199 (26.9%), 203 (27.4%), 103 (13.9%) and 37 (5.0%) patients, respectively. The prevalences of overweight/obesity, high blood pressure, high glucose level, high triglyceride level and low high density lipoproteins cholesterol level were 53.8%, 47.6%, 23.2%, 40.6% and 72.1%, respectively. The prevalence of MetS was not significantly different between the paroxysmal AF group and the persistent/permanent AF group (44.6% vs 52.9%, P = 0.064). The five components of MetS except overweight/obesity (69.3% vs 49.8%, P < 0.001) were not significantly different between the aforementioned two groups. The left atrium diameter increased with the sum of the MetS components. The left atrium diameter in the MetS group was significantly higher than that in the non-MetS group both in patients with paroxysmal AF and in patients with persistent/permanent AF.</p><p><b>CONCLUSIONS</b>The prevalence of MetS in patients with AF prior to catheter ablation is high. Further study and prevention are needed.</p>

Effects of perindopril and spirolactone on plasma aldosterone and left atrial remodeling in a canine model of atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of perindopril and spirolactone on plasma aldosterone (Ald) and left atrial remodeling and function in a canine model of atrial fibrillation (AF).</p><p><b>METHODS</b>Adult dogs were randomly assigned to receive normal diet (group A), perindopril (group B, 1 mgxkg(-1)xd(-1)) and spironolactone (group C, 10 mgxkg(-1)xd(-1), n = 6 each) and rapid paced (500 beats/min) for 8 weeks. Plasma Ald levels as well as atrial dimension and function at baseline and at 4 and 8 weeks after pacing were measured by RIA and echocardiography, respectively. Incidence of maintained AF and AF duration were recorded when pacing was stopped after 8 weeks of pacing. Left and right atrial tissues were collected for measurements of tissue Ald levels and fibrosis.</p><p><b>RESULTS</b>Plasma Ald was similar among groups at baseline (P > 0.05) and significantly increased post 4 and 8 weeks pacing in group A (P < 0.05) while remained unchanged post pacing in group B and C (P > 0.05) compared to respective baseline level. Atrial Ald was significantly lower in group B and C compared that in group A post 8 weeks pacing (P < 0.05). Left atrial dimension, end-systolic and end-diastolic volume were significantly increased while left atrial ejection fraction (LAEF) was significantly reduced post pacing in group A (all P < 0.05 vs. baseline) and thses changes were significantly attenuated in group B and C (P < 0.05 vs. group A). Incidence of maintained AF and AF duration post pacing as well as interstitial collagen volume fraction were significantly lower in group B and C compared those in group A (P < 0.05).</p><p><b>CONCLUSION</b>Increased Ald might be an important pathogenesis for AF formation and progression, spironolactone and perindopril could attenuate atrial remodeling and improve atrial function by reducing plasma and tissue Ald levels in this model.</p>

Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear.</p><p><b>METHODS</b>From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test.</p><p><b>RESULTS</b>Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75).</p><p><b>CONCLUSIONS</b>PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.</p>

Recurrent atrial tachycardia and atrial fibrillation after circumferential pulmonary vein ablation: what's the difference? / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recurrent atrial tachyarrhythmia (ATa) after circumferential pulmonary vein ablation (CPVA) includes atrial tachycardia (AT) and atrial fibrillation (AF). However, whether there are some differences in clinical course and mechanisms between the recurrent AT and the recurrent AF remained unclear. This study was conducted to investigate the incidence, mechanism, clinical course of the recurrent AT and AF in patients under CPVA.</p><p><b>METHODS</b>One hundred and thirty consecutive patients (M/F = 95/35) with highly symptomatic and multiple antiarrhythmic drugs (AADs) refractory paroxysmal (n = 91) or persistent (n = 39) AF were included. The ablation protocol consisted solely of two continuous circular lesions around the ipsilateral pulmonary veins (PV) guided by CARTO system. The endpoint of CPVA is PV isolation. For patients with recurrent ATa within 2 months after the initial procedure, cardioversion with direct current was attempted if the ATa lasted for more than 24 hours. A repeat ablation procedure was performed only for patients with AADs refractory recurrent ATa and at least followed up for 2 months after the initial procedure.</p><p><b>RESULTS</b>Within 2 months after the initial procedure, 52 patients (40.0%) had experienced episodes of symptomatic recurrent ATa. Among them, 23 patients (44.2%) with recurred AT alone (AT group), 14 patients (26.9%) with recurred AF alone (AF group), and 15 patients (28.8%) with recurred AT and AF (AT plus AF group). The delayed cure rate (65.2%) in AT group was significant higher than that in AF group (21.4%, P < 0.05) and AF plus AT group (26.7%, P < 0.05). A repeat ablation was performed in 21 patients, including 6 patients with recurrent AT alone, 8 patients with recurrent AF alone, and 7 patients with recurrent AF plus AT. The mean number of PV gaps was 1.2 +/- 0.4 in AT group, which was significantly lower than that in AF group (2.6 +/- 0.7, P < 0.05) and AF plus AT group (2.0 +/- 0.6, P < 0.05). Delayed cure rate and number of PV gaps between AF group and AF plus AT group were comparable (P > 0.05).</p><p><b>CONCLUSIONS</b>Present study indicates that recurrent AT and AF after CPVA have the different clinical course and different electrophysiological findings during repeat procedure as follows: (1) After CPVA, spontaneous resolution of recurrent ATa was mainly found in patients with recurrent AT alone (about two thirds patients). (2) The type of recurrent ATa after CPVA is associated with the number of PV gaps.</p>

The influence of persistent rapid atrial pacing on the levels of connexin 43 and type III collagen in pulmonary vein and atrium in a canine model / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the influence of persistent rapid atrial pacing on the levels of connexin 43 (Cx43) and type III collagen in pulmonary vein and atrium in a canine model.</p><p><b>METHODS</b>Sixteen mongrel dogs were divided into rapid atrial pacing (RAP) group (n = 8) and normal control group (n = 8) randomly. In the RAP group, atrial pacing was performed with a rate of 400 bpm for 10 weeks to establish atrial fibrillation model. The tissues of left superior pulmonary vein (LSPV), left atrial free wall (LAFW) and right atrial appendage (RAA) were collected from each dogs. The levels of Cx43 and type III collagen were measured in each tissue.</p><p><b>RESULTS</b>Ten weeks later, persistent atrial fibrillation was induced in all dogs in RAP group. The level of Cx43 in RAP group was higher than that in normal control group (LSPV: 3370.91 +/- 275.11 vs 1405.82 +/- 90.38, P < 0.05; LAFW: 2448.68 +/- 272.10 vs 1467.12 +/- 147.93, P < 0.05, RAA: 2331.96 +/- 199.61 vs 1288.27 +/- 216.22, P < 0.05). The level of Cx43 in LSPV was higher than that in LAFW and RAA in RAP group, whereas the difference between LAFW and RAA was not significant in RAP group. The quantities of type III collagen in RAP group were higher than those in normal control group (LSPV: 3301.97 +/- 309.70 vs 1404.56 +/- 178.02, P < 0.05; LAFW: 2477.86 +/- 190.43 vs 1479.20 +/- 187.17, P < 0.05; RAA: 2045.92 +/- 139.43 vs 1417.07 +/- 139.43, P < 0.05). The quantities of type III collagen in LSPV was higher than those in LAFW and RAA in RAP group.</p><p><b>CONCLUSIONS</b>Persistent rapid atrial pacing could increase the levels of Cx43 and type III collagen in pulmonary vein and atrium in a canine model of atrial fibrillation. The levels of Cx43 and type III collagen in pulmonary vein were higher than those in atrium. This findings indicated that pulmonary vein may be a crucial regions in maintaining atrial fibrillation.</p>

Impact of different ablation strategies on the delayed cure after trans-catheter ablation for treating patients with atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Delayed cure had been observed in recurrent cases after index ablation of atrial fibrillation (AF), however, its mechanism and incidence have not been elucidated in detail. This study aims to investigate the impact of different ablation strategies on the incidence of delayed cure and its possible mechanisms after trans-catheter ablation of AF.</p><p><b>METHODS</b>One hundred and fifty-one consecutive cases with highly symptomatic, drug refractory AF were included in this study [M/F = 109/42, mean age (56.0 +/- 11.2) (18 - 79) years]. Segmental pulmonary vein ablation (SPVA) was performed in 83 patients with the guidance of circular mapping catheter (SPVA Group), circumferential PV linear ablation (CPVA) was carried out in the rest 68 cases under the guidance of 3 dimensional mapping system in conjunction with circular mapping catheter (CPVA Group). Delayed cure was defined as that early recurrence of atrial tachyarrhythmias (AF, atrial tachycardia, or atrial flutter) after ablation procedure was no longer observed during subsequent follow-up, and stable sinus rhythm was maintained > or = 2 months.</p><p><b>RESULTS</b>Early recurrence of atrial tachyarrhythmias was detected in 41 cases from SPVA group and 23 cases from CPVA group, and delayed cure occurred in 21.9% (9/41) of the cases from SPVA group and 47.8% (11/23) of the cases from CPVA group, more delayed cure in later group was observed (P < 0.05). Meanwhile, patients in SPVA group took a longer time to achieve a delayed cure [(27.0 +/- 18.0) days vs (14.0 +/- 8.1) days, P < 0.05], and presented more recurrent episodes [(3.50 +/- 1.08) times a week vs (2.42 +/- 1.11) times a week, P < 0.05]. However, recurrent episodes after index ablation were markedly decreased in cases with delayed cure from both groups (P < 0.05).</p><p><b>CONCLUSIONS</b>Despite of an early recurrence of atrial tachyarrhythmias after index ablation of AF, delayed cure occurs in a significant number of patients undergoing either SPVA or CPVA. However, different ablation strategies place different impact on the delayed cure, more delayed cure is obtained with CPVA approach, and the delayed cure occurs earlier with this approach; the average recurrent episodes before delayed cure are also less frequently detected in CPVA group compared with those in SPVA group.</p>

Clinical results of circumferential pulmonary vein linear ablation in 100 patients with atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the feasibility and efficacy of treating atrial fibrillation (AF) with circumferential pulmonary vein (PV) linear ablation guided by 3 dimensional mapping system and single circular mapping catheter.</p><p><b>METHODS</b>From April 2004 to January 2005, PV isolation with circumferential PV linear ablation guided by CARTO system (in 76 patients) or EnSite-NavX system (in 24 patients) was performed in 100 consecutive patients with significantly symptomatic, drug refractory AF. The procedural end-point was complete electrical isolation of bilateral PV.</p><p><b>RESULTS</b>Up to 200 linear circles were produced around each ipsilateral PVs in all 100 cases, and 95.0% (190/200) of PV isolation rate was achieved with a mean procedure time of 150-365 (240 +/- 65) min and a mean fluoroscopy time of 23-61 (37 +/- 12) min, respectively. Eight cases with recurrent AF (8.0%) underwent second session. Cumulative atrial tachyarrhythmias-free rate was 85.0% (85/100) during a mean follow-up of 5.5-12 (10.2 +/- 5.7) months. Atrial tachyarrhythmias-free rate was 66.0% (66/100), 82.0% (82/100), 87.0% (87/100), 85.0% (85/100), 85.0% (85/100), and 88.6% (70/79) during the follow up at 1 month, 2 months, 3 months, 4 months, 5 months and 6 months, respectively. There were 2 complications (1 tamponade and 1 PV stenosis), which were rehabilitated after conservative treatment.</p><p><b>CONCLUSION</b>PV isolation with circumferential PV linear ablation guided by 3 dimensional mapping system is safe and effective for treating AF.</p>

Comparison of different pulmonary vein isolation strategies for patients with paroxysmal atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To compare two catheter ablation strategies for pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (PAF).</p><p><b>METHODS</b>Fifty consecutive patients who underwent PV isolation by circumferential PV ablation (CPVA group) were compared with 50 consecutive patients who underwent PV isolation by segmental PV ablation (SPVA group). The enrolled subjects in this retrospective study were patients with frequent attacks (more than 3 times per month) and symptomatic PAF. Procedure-related parameters, safety and clinical outcome within 6 months after procedures for the 2 strategies were analyzed.</p><p><b>RESULTS</b>The characteristics and mean procedure time were comparable between the 2 groups. The mean fluoroscopy time and mean ablation time were 57 min +/- 11 min and 42 min +/- 9 min in the SPVA group and 31 min +/- 8 min and 61 min +/- 13 min in the CPVA group (both P < 0.01), respectively. After the first procedure, symptomatic atrial tachyarrhythmias (ATa) recurred in 24 (48%) of 50 patients who underwent SPVA and 15 (30%) of 50 patients who underwent CPVA within 3 months (P = 0.10). During 6 months of follow-up, 82% of patients with CPVA and 60% of patients with SPVA were free of symptomatic ATa without any antiarrhythmic drugs for at least 3 months (P < 0.05). One patient per each group developed asymptomatic right superior PV stenosis.</p><p><b>CONCLUSION</b>In patients with PAF, CPVA compares favorably with SPVA, but either of them yields a similar clinical safety.</p>