Progressive remodeling of the atrial substrate--a novel finding from consecutive voltage mapping in patients with recurrence of atrial fibrillation after catheter ablation

Background: Atrial substrate properties have been demonstrated to be related to atrial arrhythmias. This study investigated whether the atrial substrate exhibits progressive remodeling in patients with recurrence of atrial fibrillation (AF) after catheter ablation.
Methods and Results: Fifteen consecutive AF patients (52 ± 12 years old, 12 males) underwent the same mapping technique (NavX, St. Jude Medical, Minnetonka, MN, USA) and same ablation technique for primary AF and recurrence of AF (170 ± 66 days after the first procedure). The bipolar mean peak-to-peak voltage (PPV) of the global left atrium during sinus rhythm significantly decreased in the second procedure (2.25 ± 0.62 vs. 1.79 ± 0.60 mV, P = 0.008). Also, the percentage of the surface area of the low voltage zone (LVZ; less than 0.5 mV) in the left atrium increased from 6 ± 4% to 13 ± 6% (P = 0.001) in the second procedure. There was no significant change in the right atrial bipolar mean PPV or surface area of the LVZ in the second procedure.
Conclusion: Atrial substrate remodeling with a progressive decrease in the left atrial voltage was demonstrated in patients with recurrent AF.     

Spatial correlation of left atrial low voltage substrate in sinus rhythm versus atrial fibrillation: The rhythm specificity of atrial low voltage substrate

Introduction

Improved sinus rhythm (SR) maintenance rates have been achieved in patients with persistent atrial fibrillation (AF) undergoing pulmonary vein isolation plus additional ablation of low voltage substrate (LVS) during SR. However, voltage mapping during SR may be hindered in persistent and long-persistent AF patients by immediate AF recurrence after electrical cardioversion. We assess correlations between LVS extent and location during SR and AF, aiming to identify regional voltage thresholds for rhythm-independent delineation/detection of LVS areas. (1) Identification of voltage dissimilarities between mapping in SR and AF. (2) Identification of regional voltage thresholds that improve cross-rhythm substrate detection. (3) Comparison of LVS between SR and native versus induced AF.

Methods

Forty-one ablation-naive persistent AF patients underwent high-definition (1 mm electrodes; >1200 left atrial (LA) mapping sites per rhythm) voltage mapping in SR and AF. Global and regional voltage thresholds in AF were identified which best match LVS < 0.5 mV and <1.0 mV in SR. Additionally, the correlation between SR-LVS with induced versus native AF-LVS was assessed.

Results

Substantial voltage differences (median: 0.52, interquartile range: 0.33–0.69, maximum: 1.19 mV) with a predominance of the posterior/inferior LA wall exist between the rhythms. An AF threshold of 0.34 mV for the entire left atrium provides an accuracy, sensitivity and specificity of 69%, 67%, and 69% to identify SR-LVS < 0.5 mV, respectively. Lower thresholds for the posterior wall (0.27 mV) and inferior wall (0.3 mV) result in higher spatial concordance to SR-LVS (4% and 7% increase). Concordance with SR-LVS was higher for induced AF compared to native AF (area under the curve[AUC]: 0.80 vs. 0.73). AF-LVS < 0.5 mV corresponds to SR-LVS < 0.97 mV (AUC: 0.73).

Conclusion

Although the proposed region-specific voltage thresholds during AF improve the consistency of LVS identification as determined during SR, the concordance in LVS between SR and AF remains moderate, with larger LVS detection during AF. Voltage-based substrate ablation should preferentially be performed during SR to limit the amount of ablated atrial myocardium.     

Relationship between arrhythmogenic pulmonary veins and the surrounding atrial substrate in patients with paroxysmal atrial fibrillation

Arrhythmogenic PVs and the Fibrillatory Activities . Introduction: The relationship between pulmonary veins (PVs) with atrial fibrillation (AF) initiating triggers and their surrounding atrial substrate has not been elucidated. We aimed to clarify the atrial substrate properties around the PVs. Methods and Results: Twenty‐three paroxysmal AF patients were studied with the identification of PV initiating triggers. High‐density mapping of the dominant frequency (DF, 1200 Hz) and the mean degree of the complex fractionated electrograms (CFE mean interval over 6 seconds) was evaluated in 2 zones (zone 1: < 5 mm, zone 2: 5–15 mm from the PVs) and the left atrial (LA) using a NavX system prior to the PV isolation. High‐DFs (>8 Hz) and continuous CFEs (<50 ms) were identified in 1.5 ± 0.9 and 2.3 ± 1.1 regions per patient, respectively. Most of the high‐DF regions (86%) and continuous CFE regions (77%) were located within 15 mm of the PV ostia. Of those, 75% of the high‐DF regions and 54% of the continuous CFE regions were related to arrhythmogenic PVs. There was a significant DF gradient from arrhythmogenic PV zone 1 to zone 2, while the mean CFE exhibited a significant gradient between arrhythmogenic PV zone 2 and the rest of the LA. Additionally, 69% of the procedural AF termination sites were at arrhythmogenic PV zone 2. Conclusion: Evaluation of the atrial substrate properties may be useful for locating arrhythmogenic PVs during AF and defining the extent of the circumferential PV isolation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 405‐410)     

Biatrial and three-dimensional mapping of spontaneous atrial arrhythmias in patients with refractory atrial fibrillation

INTRODUCTION: While atrial fibrillation (AF) initiation in the pulmonary veins has been well-studied, simultaneous biatrial and three-dimensional noncontact mapping (NCM) has not been performed. We hypothesized that these two techniques would provide novel information on triggers, initiation, and evolution of spontaneous AF and permit study of different AF populations. METHODS AND RESULTS: The origin of atrial premature beats (APBs), onset of spontaneous AF and its evolution were analyzed in 50 patients with AF in the presence or absence of structural heart disease (SHD) and in different AF presentations (group A: Persistent, group B: Paroxysmal). In 45 patients, spontaneous APBs in the right atrium (RA; n = 60) and left atrium (LA; n = 25) with similar regional distributions regardless of heart disease status were demonstrated. In total, 22 patients (44%) had > or =2 disparate regional origins. Biatrial regional foci were seen with equal frequency in patients with SHD (31%), without SHD (40%), in group A (32%), and in group B (36%). Biatrial mapping and NCM showed organized monomorphic atrial tachyarrhythmias arising in the RA (17), septum (17), or LA (21) and were classified as atrial flutter (RA = 34, LA = 8), macro-reentrant atrial tachycardia (RA = 1, LA = 3) or focal atrial tachycardia (RA = 2, LA = 7). Their regional distribution was more extensive in patients with SHD and persistent AF compared with patients without SHD or paroxysmal AF. Simultaneous biatrial tachycardias were observed only in group A patients and those with SHD. CONCLUSIONS: Simultaneous biatrial and NCM permits successful AF mapping in different AF populations and demonstrates a biatrial spectrum of spontaneous triggers and tachycardias. Organized monomorphic tachycardias with multiple unilateral or biatrial locations are commonly observed in human AF. Patients with heart disease or persistent AF have a more extensive distribution as well as simultaneous coexistence of multiple tachycardias during AF.     

胺碘酮对特发性房颤心房重构逆转作用观察

目的 :探讨胺碘酮对特发性房颤的治疗及对逆转心房心肌重构的作用。方法 :选择 1998- 0 6～ 2 0 0 0 - 0 7住院的特发性房颤患者 （除外房颤持续时间小于 6月和阵发性房颤间隔小于 1月 ,每次持续时间少于 48h者 ） 94例。随机分为胺碘酮治疗组 32例 ,普罗帕酮治疗组 32例及安慰剂组 30例。治疗前后行心电图、心脏超声、肝、肾功及甲状腺功能检查。出院后嘱患者 1,3,6 ,12月复查上述项目 1次。结果 :胺碘酮与普罗帕酮治疗组 ,均可使特发性房颤复律 ,但胺碘酮组较普罗帕酮组复律时间稍长 （约 1周 ） ,维持窦性心律的作用中 ,胺碘酮优于普罗帕酮组 ,12月后转复成功率分别为 81%和 5 6 % ,与安慰剂组自动复律 2 0 % （6 / 30 ）比较有显著差异 （P<0 .0 1）。随访 1,3,6 ,12月胺碘酮组左心房直径缩小 ,左心室舒张早期经二尖瓣血流的最高值 （E峰值 ）和左心房收缩时经二尖瓣血流的最大值 （A峰值 ）、E/ A增大。1,3,6 ,12月间比较有显著性差异 （P<0 .0 1） ,普罗帕酮组上述指标有所改善 ,但差异不显著 （P>0 .0 5 ） ,安慰剂组则无变化。结论 :胺碘酮对特发性房颤复律及对逆转心房心肌重构安全有效     

A novel individualized substrate modification approach for the treatment of long-standing persistent atrial fibrillation: Preliminary results

Background

The most effective approach for long-standing persistent atrial fibrillation (LPAF) ablation remained undetermined. Our goal was to explore the heterogeneous left atrial substrate in patients with LPAF and to evaluate the effectiveness of a novel individualized substrate modification (ISM) approach in LPAF ablation.

Methods

One hundred and twenty-four patients with LPAF were randomized to ISM group (n = 64) or stepwise ablation (SA) group (n = 60). After pulmonary vein isolation, ISM was performed in the ISM group and SA was applied in the SA group. The clinical effectiveness after a single and a repeated procedure was compared.

Results

The total procedural time was significantly shorter in ISM than that in SA. In the ISM group, mild left atrial substrate was observed in 17 (27.4%), moderate in 26 (41.9%) and severe in 19 (30.6%) patients after successful cardioversion of the 62 patients. The intention-to-treat analysis showed that sinus rhythm was maintained in 65.5% of patients in the ISM group and in 45.0% of patients in the SA group after a single procedure, P = 0.04. Atrial tachycardia (AT) recurred in 5 of 22 in the ISM group and in 20 of 33 in the SA group, P = 0.01. After a repeated procedure, 75% of patients in the ISM group and 63.3% of patients in the SA group were free of further recurrence, P = 0.16.

Conclusions

Left atrial substrate varied noticeably in patients with LPAF. The ISM approach was superior to SA approach in terms of procedural time, recurrence rate of AT and clinical effectiveness after a single procedure. However, they yielded comparable outcomes after a repeated procedure.     

Atrial fibrosis and substrate based characterization in atrial fibrillation: Time to move forwards

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia in clinical practice. However, current therapeutic interventions for atrial fibrillation have limited clinical efficacy as a consequence of major knowledge gaps in the mechanisms sustaining atrial fibrillation. From a mechanistic perspective, there is increasing evidence that atrial fibrosis plays a central role in the maintenance and perpetuation of atrial fibrillation. Electrophysiologically, atrial fibrosis results in alterations in conduction velocity, cellular refractoriness, and produces conduction block promoting meandering, unstable wavelets and micro-reentrant circuits. Clinically, atrial fibrosis has also linked to poor clinical outcomes including AF-related thromboembolic complications and arrhythmia recurrences post catheter ablation. In this article, we review the pathophysiology behind the formation of fibrosis as AF progresses, the role of fibrosis in arrhythmogenesis, surrogate markers for detection of fibrosis using cardiac magnetic resonance imaging, echocardiography and electroanatomic mapping, along with their respective limitations. We then proceed to review the current evidence behind therapeutic interventions targeting atrial fibrosis, including drugs and substrate-based catheter ablation therapies followed by the potential future use of electro phenotyping for AF characterization to overcome the limitations of contemporary substrate-based methodologies.     

Investigation of the predictors of transition to persistent atrial fibrillation in patients with paroxysmal atrial fibrillation

BACKGROUND: Until now, no clinically useful indicators have existed that predict the transition from paroxysmal to persistent atrial fibrillation (AF). HYPOTHESIS: The current prospective study was conducted for identifying predictors of progression to persistent AF over the long term. METHODS: We studied 102 consecutive patients (mean age: 55 +/- 10 years: 75 men and 27 women) diagnosed with paroxysmal AF. Standard 12-lead electrocardiography, echocardiography, and P-wave-triggered signal-averaged electrocardiography (P-SAECG) were performed on all patients at the time of their entry into the study. RESULTS: The mean follow-up period was 61 +/- 13 months. Group 1 (n = 66) comprised patients in whom paroxysmal AF did not progress to persistent AF, and Group 2 (n = 36) comprised those who developed persistent AF. In Group 2 the patients were significantly older, and P-wave dispersion, filtered P-wave duration (FPD), and left atrial dimension were significantly higher than in Group 1 (p < 0.05). The root mean square voltage for the last 30 ms of the filtered P-wave was also significantly lower in Group 2 (p < 0.05). Multivariate logistic regression analysis using these five factors identified left atrial dimension (odds ratio [OR] 2.29; 95% confidence interval [CI] 1.16-4.54; p = 0.02) and FPD (OR 2.71; 95% CI 1.78-4.13; p < 0.01) as independent predictors of transition to persistent AF. Left atrial dimension > or = 40 mm predicted progression to persistent AF with a sensitivity of 64%, specificity of 76%, positive predictive value of 59%, negative predictive value of 79%, and an accuracy of 71%. An FPD > or = 150 ms predicted persistent AF with a sensitivity of 81%, specificity of 91%, positive predictive value of 88%, negative predictive value of 90%, and an accuracy of 87%. Filtered P-wave duration was a significantly more sensitive and specific predictor than left atrial dimension (p < 0.05). CONCLUSION: We conclude that FPD is a clinically useful predictor of progression from paroxysmal to persistent AF over the long term.     

Biatrial volume ratio predicts low voltage areas in atrial fibrillation

BackgroundLeft atrial volume (LAV) and low voltage areas (LVAs) are acknowledged markers for worse rhythm outcome after ablation of atrial fibrillation (AF). Some studies reported the importance of increased right atrial volume (RAV) as a predictor for arrhythmia recurrences in AF patients.ObjectiveTo investigate association between the LAV/RAV ratio and LVAs presence.MethodsPatients undergoing first AF ablation were included. LVAs were assessed peri‐procedurally using high‐density 3D maps and defined as <0.5 mV. All patients underwent pre‐procedural cardiovascular magnetic resonance imaging. LAV (biplane) and RAV (monoplane 4‐chamber) were assessed prior to ablation, and the LAV/RAV ratio was calculated.ResultsThe study population included 189 patients (age mean 63 ± 10 years, 33% women, 57% persistent AF, 22% LVAs). There were 149 (79%) patients with LAV > RAV. In univariable analysis LAV > RAV was associated with LVAs (OR 6.803, 95%CI 1.395–26.514, p = .016). The association remained robust in multivariable model after adjustment for persistent AF, CHA₂DS₂‐VASc score, and heart rate (OR 5.981, 95%CI 1.256–28.484, p = .025). Using receiver operator curve analysis, LAV > RAV (AUC 0.668, 95%CI 0.585–0.751, p = .001) was significant predictor for LVAs. In multivariable analysis, after adjustment for age, persistent AF, and renal function, RAV≥LAV was threefold higher in males (OR 3.040, 95%CI 1.050–8.802, p = .04).ConclusionsLAV > RAV is useful for the prediction of electro‐anatomical substrate in AF. LAV > RAV was associated with LVAs presence, while male sex remained associated with RAV≥LAV and less LVAs.     

长程持续性房颤消融术中规整房速的处理

目的探索慢性房颤导管消融中规则房速的发生机制与处理方法。方法选择2009年1月至2013年5月在厦门心脏中心确诊并接受导管消融治疗的慢性房颤患者102例,采用递进式导管消融策略,分析慢性房颤患者在消融中发生规则房速的可能机制并进行相应处理。结果102例患者中,4例（4．9％）在肺静脉电隔离过程中转为窦律,3例（2．9％）在行碎裂电位消融时转为窦律,46例经碎裂电位消融及心房线性消融过程中转为规则房速（45．1％）,47例（46．1％）仍维持房颤。规则房速的发生机制为局灶自律性（17．6％）、折返性（77．8％）、其它（4．6％）,消融成功率为81．6％。结论慢性房颤递进式导管消融中,规则房速的发生机制多为大折返性,导管消融此类房速成功率较高。     

持续性房颤患者左房球形指数与左房自发显影的相关性

目的 探讨持续性房颤患者发生左房自发显影的临床特征,分析其与反映左房球形化的左房球形指数之间的相关性。方法 回顾性分析首都医科大学附属北京同仁医院2021年8月至2022年12月收治的96例非瓣膜性持续性房颤患者的临床资料。根据经食道心脏超声有无左房自发显影表现,将患者分为左房自发显影组(54例)及对照组(42例)。对2组患者合并症、实验室检查结果、心脏超声参数及左房球形指数进行比较。采用SPSS 22.0统计软件进行数据分析。根据数据类型,分别采用t检验、Mann-Whitney U检验或χ²检验进行组间比较。应用Pearson相关分析左房球形指数与合并症及心脏超声参数的相关性。采用logistic回归分析左房自发显影的危险因素。结果 左房自发显影组患者女性患者比例、CHA2DS2-VASc评分、D-二聚体水平、氨基末端B型钠尿肽前体(NT-proBNP)水平、左房前后径与横径、左房球形指数均高于对照组,差异有统计学意义(P<0.05)。左房球形指数与体质量指数(BMI)、心力衰竭、左室舒张末内径(r=0.236,0.272,0.212;P<0.05...     

射血分数降低的心力衰竭病人持续性心房颤动危险因素研究

目的 探讨射血分数降低的心力衰竭(HFrEF)病人持续性心房颤动(房颤)的相关危险因素.方法 收集南京市高淳人民医院2017年1～12月住院治疗的HFrEF合并房颤病人78例,根据病人房颤类型分为阵发性房颤组16例以及持续性房颤组62例.比较2组病人一般情况的差异,并应用多因素Logistic逐步回归分析及ROC曲线分...     

立体心电图分析阵发性房颤患者心房的电生理特性

目的应用立体心电图(three-dimensional electrocardiogram,3D-ECG)分析阵发性房颤患者心房传导时间、心房除极角度和振幅的变化。方法入选在住院的阵发性房颤患者13例,对照组患者15例。分别应用立体心电图仪记录窦律下的立体心电图,分析后比较两组患者心房传导时间,P波除极振幅及角度。同时记录患者入院时超声心动图中左心房内径数值进行比较。结果两组患者比较左心房内径无显著差异。阵发性房颤组与对照组心房传导时间分别为123.75±11.67msvs.111.39±13.52ms,两组比较有显著性差异(p<0.05)。而在心房除极角度、振幅上,两组无显著差异。与对照组比较,阵发性房颤组患者P环初始部的运行方向与泪点疏密程度无明显变化,但在P环中间至终末部分,P环运行方向及泪点疏密出现明显变化,并且可看到明显的曲折、弯曲。但在除极末20ms的振幅,房颤患者较对照组明显降低(0.05±0.013mvvs.0.036±0.014mv,p<0.05),除极末30ms、40ms处两组振幅无显著差异。结论阵发性房颤患者可以出现心房传导时间延长、心房除极末振幅的改变和立体三维P环运行方向及泪点疏密程...     

动态心房超速起搏预防阵发性房颤

目的观察动态心房超速起搏预防阵发性房颤的临床疗效和安全性。方法选择病态窦房结综合症伴阵发性房颤,并需植入永久起搏器的患者8例,分别植入具有动态心房起搏功能的起搏器,PacessetterTrilogy23643例,VitatronSelectionTM900E5例;随访6个月,前3个月不打开动态心房起搏功能,后3个月打开动态心房起搏功能,根据起搏器记录到的模式转换次数和持续时间来判断其预防房颤发作的疗效。结果打开动态心房起搏功能前后,患者房颤发作的次数分别为2437±956次/月和472±135次/月(P<0.05);模式转换持续时间分别为173±105小时/月和48±25小时/月(P<0.05);房颤负荷分别为33±8%和10±7%(P<0.05)。结论动态心房超速起搏,是阵发性房颤预防治疗的有效和安全的方法之一。