Incidence and location of focal atrial fibrillation triggers in patients undergoing repeat pulmonary vein isolation: implications for ablation strategies

INTRODUCTION: The etiology of atrial fibrillation (AF) recurrences after pulmonary vein (PV) isolation is not well described. The aim of this study was to examine the reason for recurrent AF in patients undergoing a repeat attempt at AF trigger ablation. METHODS AND RESULTS: Patients with recurrent AF more than 1 month after ablation returned for repeat mapping and ablation. A circular mapping catheter was advanced to each previously targeted PV ostium to determine if the PV was still electrically isolated. Ectopy then was provoked with isoproterenol (up to 20 microg/min), burst pacing, and pacing into AF followed by cardioversion. The location of ectopy triggering atrial premature depolarizations (APDs) or AF was noted. Of 226 patients who underwent ablation of AF triggers, 34 (8 women and 26 men; age 56 +/- 10 years) with recurrent AF returned for a repeat procedure 207 +/- 183 days after the first procedure. There were 84 previously completely isolated PVs in these 34 patients. Thirty-three (39%) of 84 previously isolated PVs were still completely isolated at the time of the second procedure. Fifty-one PVs (61%) had evidence of recovered PV potentials. Fifty triggers of APDs and AF (n = 30) or APDs only (n = 20) were identified in these 34 patients. The majority of triggers [27/50 (54%)] originated from previously targeted PVs. Sixteen triggers [16/50 (32%)] originated from previously nontargeted PVs. CONCLUSION: The majority of AF recurrences originate from previously isolated PVs. One third of recurrent triggers originated from PVs that were not targeted during the initial ablation session. Although empiric isolation of all PVs may reduce recurrences, strategies to ensure ostial PV isolation and to prevent recurrent PV conduction after ablation should have the greatest impact on reducing AF recurrence.     

Electroanatomic remodeling of the left atrium in paroxysmal and persistent atrial fibrillation patients without structural heart disease

Atrial Remodeling in Atrial Fibrillation. Introduction: The nature of the atrial substrate thought to contribute toward maintaining atrial fibrillation (AF) outside the pulmonary veins remains poorly defined. Therefore, our objective was to determine whether patients with paroxysmal and persistent AF have an abnormal electroanatomic substrate within the left atrium (LA). Methods and Results: Thirty‐one patients with AF (17 paroxysmal AF and 14 persistent AF) were compared with 15 age‐matched controls with left‐sided supraventricular tachycardia (SVT). High‐density 3‐dimensional electroanatomic maps were created and the LA was divided into 8 segments for regional analysis. Bipolar voltage, conduction, and effective refractory periods (ERPs) of the posterior LA, left atrial appendage (LAA), and distal coronary sinus (CSd) and percentage complex signals were assessed. In the majority of LA regions, compared with controls, AF patients had: (1) lower mean voltage and a higher percentage low voltage; (2) slower conduction; and (3) more prevalent complex signals. Many of these changes were more marked in the persistent than the paroxysmal AF group. Conclusions: Patients with AF have lower regional voltage, increased proportion of low voltage, slowed conduction, and increased proportion of complex signals compared to controls. Many of these changes are more pronounced in persistent AF patients, suggesting there may be a progressive nature to the changes. Differences occurred in the absence of structural heart disease. These substrate abnormalities provide further insight into the progressive nature of atrial remodeling and the mechanisms involved in maintenance of AF. (J Cardiovasc Electrophysiol, Vol. 23 p. 232‐238, March 2012.)     

Morphologic remodeling of pulmonary veins and left atrium after catheter ablation of atrial fibrillation: insight from long-term follow-up of three-dimensional magnetic resonance imaging

INTRODUCTION: Understanding the structural remodeling and reverse remodeling of the left atrium (LA) and pulmonary vein (PV) after radiofrequency ablation of atrial fibrillation (AF) may provide important insights into the mechanism and management of AF. This study used magnetic resonance angiographic (MRA) images to investigate changes in PV and LA morphologies before and more than 1 year after ablation. METHOD AND RESULTS: Forty-five patients (36 men and 9 women, mean age 60 +/- 13 years) who underwent MRA before and more than 12 months (mean 21 +/- 11) after ablation of paroxysmal AF were included in the study. The patients were divided into two groups: group I included 35 patients without AF recurrence, and group II included 10 patients with late (>1 month postablation) recurrence of AF. The sizes of the LA and nonablated PV were compared before and after ablation. In group I, significant reduction of ostial area of both superior PVs was noted (left superior PV: from 2.85 +/- 0.67 to 2.59 +/- 0.73 cm2; right superior PV: from 2.89 +/- 0.85 to 2.60 +/- 0.73 cm2, both P <0.001). Geometric alteration toward a round shape was noted in the ostia of superior PVs during follow-up (eccentricity of right superior PV and left superior PV decreased from 0.31 +/- 0.10 to 0.22 +/- 0.13 and from 0.27 +/- 0.11 to 0.19 +/- 0.13, respectively, both P <0.01). However, LA volume showed only borderline reduction (from 61.52 +/- 19.06 to 56.64 +/- 17.13 mL, P=0.05). In group II, significant dilation of the LA (from 61.14 +/- 17.54 to 78.73 +/- 25.27 mL, P=0.004) and right superior PV (from 3.41 +/- 1.12 to 4.08 +/- 1.31 cm2, P=0.016) was noted during follow-up. Ostial area and eccentricity of the left superior, left inferior, and right inferior PVs and LA were similar before and after ablation. CONCLUSION: Structural remodeling of the superior PVs and LA can be reversible after successful ablation without AF recurrence; however, late recurrence of AF is associated with progressive LA dilation.     

Transesophageal echocardiographic assessment of pulmonary veins and left atrium in patients undergoing atrial fibrillation ablation

Background: Pulmonary vein (PV) antrum isolation with ganglionated plexi (GP) ablation is a novel atrial fibrillation (AF) ablation technique. The aim of this study was to evaluate acute changes in left atrial and PV flow velocities following PV antrum isolation with GP ablation using transesophageal echocardiography (TEE). Methods: TEE was performed before and after PV antrum isolation with GP ablation in 88 consecutive patients. All four PVs, when possible, were analyzed with regard to peak systolic and diastolic pulsed‐wave Doppler flow velocities. Left atrial appendage emptying velocities were also obtained. PV stenosis was defined as a peak PV Doppler flow velocity of ≥110 cm/sec with spectral broadening (turbulence). Results: All but four right inferior and four left inferior PVs were visualized. Compared to preablation values, both PV systolic and diastolic velocities increased after ablation (P < 0.05 for each of the four PVs). However, the systolic to diastolic ratio decreased significantly after ablation in all PVs (1.3 ± 0.6 to 0.9 ± 0.4, P < 0.0001, 1.2 ± 0.7 to 0.9 ± 0.4, P < 0.0001, 1.2 ± 0.6 to 1.0 ± 0.6, P = 0.035 and 1.1 ± 0.5 to 0.9 ± 0.5, P = 0.0001, for left superior, left inferior, right superior and right inferior PV, respectively). Left atrial appendage emptying velocities showed a trend towards higher values following ablation (62.7 ± 26.1 cm/sec vs. 67.5 ± 23.2 cm/sec, P = 0.07). Asymptomatic PV stenosis occurred in seven patients (seven PVs). Conclusions: PV antrum isolation with GP ablation acutely increased PV flow velocities and altered the pattern of PV Doppler flow signal, likely correlating with increased left atrial pressures, but did not appear to adversely impact on left atrial appendage physiology. (Echocardiography 2011;28:775‐781)     

The effect of left atrial remodeling after cryoballoon ablation and radiofrequency ablation for paroxysmal atrial fibrillation

BackgroundCryoballoon ablation (CBA) and radiofrequency ablation (RFA) are the most common procedures used to treat refractory atrial fibrillation (AF) and are performed through pulmonary vein isolation (PVI). Studies have shown that CBA can approximately match the therapeutic effects of RFA against AF. However, few studies have investigated the difference between CBA and RFA of the effects on left atrial remodeling for paroxysmal AF.ObjectiveAtrial remodeling is considered pivotal to the occurrence and development of AF, therefore we sought to assess the influence of atrial remodeling in patients with paroxysmal AF after CBA and RFA in this study.MethodsIn this nonrandomized retrospective observational study, we enrolled 328 consecutive patients who underwent CBA or RFA for refractory paroxysmal AF in May 2014 to May 2017 in our hospital. After propensity score matching, 96 patients were included in the CBA group, and 96 were included in the RFA group. Patients were asked to undergo a 12‐lead electrocardiogram, a 24‐h Holter monitor, and an echocardiogram and to provide their clinical history and symptoms at 6 months and 1, 2, and 3 years postprocedurally. Electrical remodeling of the left atrium was assessed by P wave dispersion (Pdis); structural remodeling was assessed by the left atrium diameter (LAD) and left atrial volume index (LAVI) during scheduled visits.ResultsAs of January 2020, compared with baseline, at 1 year, 2 years, and 3 years after ablation, the average changes in Pdis (∆Pdis), LAD (∆LAD), and LAVI (∆LAVI) were significant in both the CBA and RFA groups. Six months after ablation, ∆Pdis, ∆LAD, and ∆LAVI were greater in the CBA group than in the RFA group. There was no significant difference between the two groups in AF/flutter recurrence, but the AF/flutter‐free survival time of CBA group may be longer than RFA group after 2 years after ablation. A higher ∆Pdis, ∆LAD, or ∆LAVI at 1 year after ablation may increase AF/flutter‐free survival.ConclusionsAlthough CBA and RFA are both effective in left atrial electrical and structural reverse‐remodeling in paroxysmal AF, CBA may outperform RFA for both purposes 6 months after ablation. However, during long‐term follow‐up, there was no significant intergroup difference.     

冷冻球囊消融与射频消融对阵发性心房颤动患者心房重构的影响

目的:比较冷冻球囊消融(CBA)与射频消融(RFA)对阵发性心房颤动(房颤)患者心房重构的影响.方法:本研究选取在2014年5月-2017年5月于郑州大学第一附属医院因阵发性房颤行CBA或RFA治疗的患者.所有患者均于术前、术后半年、1年、2年和3年时行12导联心电图或24 h动态心电图和超声心动图检查.左心房电重构通...     

Predictors of very late recurrence of atrial fibrillation after circumferential pulmonary vein ablation

BACKGROUND: Early recurrence of atrial fibrillation (ERAF) after catheter ablation is common and has been thoroughly studied. However, very late recurrence of atrial fibrillation (VLRAF) is rarely researched, and its characteristics have not been determined. HYPOTHESIS: The aim of this study was to investigate the clinical characteristics of VLRAF after circumferential pulmonary vein ablation (CPVA), and to identify the risk factors for VLRAF. METHODS: We retrospectively studied 259 consecutive patients with atrial fibrillation (AF) who were referred for CPVA. Clinical variables were investigated and predictors of VLRAF were identified. RESULTS: A total of 249 patients were enrolled in this study. After a mean follow-up of 18.2 +/- 4.4 mo, 14 patients (5.6%) had VLRAF. Patients with VLRAF were more likely than those without recurrence to have ERAF (78.6% versus 17.8%, p = 0.000) and persistent AF (50.0% versus 13.0%, p = 0.000), but were less likely to achieve pulmonary vein (PV) isolation (78.6% versus 97.6%, p = 0.000). Bivariate analysis demonstrated that ERAF (odds ratio [OR] 8.148, 95% confidence interval [CI] 2.197-30.222; p = 0.002), persistent AF (OR 8.853, 95% CI 1.773-16.155; p = 0.003), and lack of PV isolation (OR 7.530, 95% CI 1.792-33.122; p = 0.006) were related to VLRAF. Multivariate logistic regression analysis only identified ERAF as a predictor of VLRAF after CPVA (OR 7.461, 95% CI 1.696-24.836; p = 0.006). CONCLUSIONS: Very late recurrence of AF is uncommon after CPVA. That occurs more commonly in patients with ERAF.     

Temporal stability of the location of the esophagus in patients undergoing a repeat left atrial ablation procedure for atrial fibrillation or flutter

Background: The esophagus may be mobile during a left atrial (LA) ablation procedure for atrial fibrillation (AF).
Objective: The goal of the study was to determine whether the location of the esophagus is stable in patients undergoing a repeat LA ablation procedure.
Methods: Forty-two patients underwent repeat LA ablation a mean of 7 ± 2 months after the initial procedure. Cinefluoroscopic images of the esophagus during a barium swallow were recorded and the course of the esophagus was tagged on the 3D map. The position of the esophagus at the index and repeat procedure were compared.
Results: At the index procedure, the esophagus was located near the left pulmonary veins (PVs) in 20 (48%), right PVs in 13 (31%), and at the mid LA in 9 (21%) patients. During the repeat procedure, the esophagus was found to be near the left PVs in 22 (52%), right PVs in 11 (26%), and at the mid LA in 9 patients (21%). In 35 of the 42 patients (83%), there was no change in the esophageal location, and in the remaining seven patients (17%), its position had shifted by ≥1 cm (range 1.0–4.0 cm).
Conclusions: In more than 80% of patients presenting for a repeat LA ablation procedure, the esophagus is in the same position relative to the PVs as during the initial procedure. Therefore, if radiofrequency ablation at a particular location was limited by the position of the esophagus, safe ablation at that site is unlikely to be feasible during a repeat procedure.     

Real-time monitoring of luminal esophageal temperature during left atrial radiofrequency catheter ablation for atrial fibrillation: observations about esophageal heating during ablation at the pulmonary vein ostia and posterior left atrium

INTRODUCTION: Left atrial radiofrequency catheter ablation (RFA) is gaining acceptance as treatment for drug-refractory atrial fibrillation (AF). This therapy has been associated with esophageal injury and atrioesophageal fistula formation causing death. METHODS: We describe 3 patients undergoing catheter ablation for AF during real-time monitoring of luminal esophageal temperature. RESULTS: We observed heating of the esophagus during short duration low power RFA, at either the left or right pulmonary vein ostia. Cryoablation at the pulmonary vein ostium in one patient resulted in esophageal cooling. Furthermore, we observed that fluoroscopic localization of the ablation catheter at a site apparently distant from the esophagus is not adequate to assure avoidance of ablation-induced esophageal heating. CONCLUSIONS: Real-time monitoring of luminal esophageal position and temperature is feasible, enhances recognition of esophageal heating, and may add useful information beyond that provided by fluoroscopic assessment of esophageal position. There is a potential role for esophageal monitoring to help avoid thermal injury to the esophagus during catheter ablation for atrial fibrillation.     

Three-dimensional anatomy of the left atrium by magnetic resonance angiography: implications for catheter ablation for atrial fibrillation

BACKGROUND: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug-refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported. METHODS: Magnetic resonance angiography (MRA) was performed in patients prior to undergoing PVI. Fifty consecutive patients with a RMPV identified by MRA were included in this study. Ridges associated with the left pulmonary veins were examined in an additional 30 patients who did not have a RMPV. Endoluminal views were reconstructed from the gadolinium-enhanced, breath-hold three-dimensional MRA data sets. Measurements were performed using electronic calipers. RESULTS: The width of the ridge separating the LPV from the LAA was found to be 3.7 +/- 1.1 mm at its narrowest point. The segment of this ridge with a width of 5 mm or less was 16.6 +/- 6.4 mm long. The width of the ridges separating the RMPV from the RSPV and the RIPV was found to be 3.0 +/-1.5 mm and 3.1 +/-1.8 mm, respectively. There were no significant differences between LPV ridges for patients with versus without a RMPV. CONCLUSION: The width of the ridges of atrial tissue separating LPV from the LAA and the RMPV from its neighboring veins may explain the technical challenge in obtaining stable catheter positions in these areas. A detailed assessment of the anatomy of these regions may improve the safety and efficacy of catheter ablation at these sites.     

Intraprocedural volume imaging of the left atrium and pulmonary veins with rotational X-ray angiography: implications for catheter ablation of atrial fibrillation

Introduction: The use of preprocedural CT or MR imaging to generate patient-specific cardiac anatomy greatly facilitates catheter ablation of the left atrium and pulmonary veins (LA-PVs) to treat atrial fibrillation (AF). This report details the accuracy and utility of an intra procedural means to generate 3-D volumetric renderings of the LA-PV anatomy: contrast-enhanced rotational X-ray angiography (3DRA).
Methods and Results: Preprocedural CT or MR imaging and intraprocedural rotational angiography was performed in 42 patients undergoing AF ablation procedures. Initially, pulmonary artery (PA) bolus-chase contrast injections were performed (20 mL, 20 mL/s) to establish pulmonary transit time and cardiac isocentering. Depending on cardiac size, either a single PA injection (80–100 mL, 20 mL/s) or two separate dedicated left/right PA branch injections were performed (60 mL each, 20 mL/s). For the latter, the two volumes of the left/right portions of the LA-PVs were registered and fused. LA-PV 3DRA images were assessed qualitatively and quantitatively in comparison with CT/MR images. The majority of the 3DRA acquisitions (71%) were deemed at least "useful" in delineating the LA-PV anatomy. The LA appendage was delineated in 57% of the cases. A blinded quantitative comparison of PV ostial diameters resulted in an absolute difference of only 2.7 ± 2.3 mm, 2.2 ± 1.8 mm, 2.4 ± 2.2 mm, and 2.2 ± 2.3 mm for the left-superior, left-inferior, right-superior, and right-inferior PVs, respectively. The feasibility for registering the 3DRA image with real-time electroanatomical mapping was also demonstrated.
Conclusion: Intraprocedural contrast-enhanced rotational angiography provides volumetric 3-D images of the LA-PVs of comparable diagnostic value to dedicated preprocedural CT/MR imaging.     

左房快速起搏对肺静脉口及心房肌电重构的影响

目的探讨左房快速起搏对肺静脉口、左右心耳电重构的影响。方法运用快速起搏左心耳的方法建立心房颤动(AF)模型,在起搏前及起搏后的第1,3,5,7d对左、右心耳;左上、左下肺静脉口;右上、右下肺静脉口的有效不应期(ERP)、ERP频率适应性、ERP离散度及心房间的传导时间进行测定。采用S1S2程序刺激,基础起搏周长(PCL)分别为400,300,200ms,S2为200ms,以5ms的步长递减。程序刺激结合Burst刺激对上述心房部位进行AF的诱发,记录AF的发生率。在第8天关闭起搏器,采用上述相同方法对起搏停止后即刻;2,4,6,24h的上述各部位的ERP进行测定。结果起搏1d后各个基础起搏周长下各部位的ERP明显缩短,ERP频率适应性降低,ERP离散度增大(P<0.05),而心房间传导时间无明显变化(P>0.05);起搏终止后各部位的ERP逐渐延长,但起搏终止后6hERP与快速起搏前相比仍有明显缩短(P<0.05);24h后ERP基本恢复到起搏前水平,两者相比无明显差异(p>0.05);随着起搏时间的延长各部位AF的诱发率逐渐增高(P<0.05)。结论快速心房起搏不仅引起心房肌电重构,亦引起肺静脉电重构。     

The different mechanisms between late and very late recurrences of atrial fibrillation in patients undergoing a repeated catheter ablation

Introduction: The mechanisms of late (<1 year after the ablation) and very late (>1 year after the ablation) recurrences of paroxysmal atrial fibrillation (AF) after catheter ablation have not been reported.
Methods and Results: Fifty consecutive patients undergoing a repeated electrophysiologic study to investigate the recurrence of paroxysmal AF after the first ablation were included. Group 1 consisted of 12 patients with very late (26 ± 13 months) and group 2 consisted of 38 patients with late (3 ± 3 months) recurrence of paroxysmal AF. In the baseline study, group 1 had a lower incidence of AF foci from the pulmonary veins (PVs) (67% vs 92%, P = 0.048) and a higher incidence of AF foci from the right atrium (50% vs 13%, P = 0.014) than group 2. In the repeated study, group 1 had a higher incidence of AF foci from the right atrium (67% vs 3%, P < 0.001) and a lower incidence of AF foci from the left atrium (50% vs 97%, P < 0.001), including a lower incidence of AF foci from the PVs (50% vs 79%, P = 0.07) and from the left atrial free wall (0% vs 29%, P = 0.046) than group 2. Furthermore, most of these AF foci (64% of group 1, 65% of group 2) were from the previously targeted foci.
Conclusion: The right atrial foci played an important role in the very late recurrence of AF, whereas the left atrial foci (the majority were PVs) were the major origin of the late recurrence of AF after the catheter ablation of paroxysmal AF.     

Technique and results of pulmonary vein angiography in patients undergoing catheter ablation of atrial fibrillation

INTRODUCTION: Delineation of pulmonary vein (PV) anatomy is an integral part of the PV isolation procedure. The aims of the present study were to (1) describe the technique of selective PV angiography, (2) show the typical fluoroscopic locations and appearance of the PVs, and (3) compare the ostial diameters of PVs measured by angiography and magnetic resonance imaging (MRI). METHODS AND RESULTS: Twenty consecutive patients undergoing a PV isolation procedure underwent selective PV angiography using a deflectable 8-French lumened catheter (Naviport, Cardima). The left superior PV (LSPV) runs upward and away from the spine in the right anterior oblique (RAO) projection and upward and toward the spine in the left anterior oblique (LAO) projection. The opposite is true for the right superior PV (RSPV). The left inferior PV (LIPV) has a bull's-eye appearance in the RAO projection, and the right inferior PV (RIPV) has a bull's-eye appearance in the LAO projection due to their end-on trajectories. The LIPV in the LAO projection and the RIPV in the RAO projection run horizontally toward the spine. An excellent correlation was noted in PV ostial size as assessed by angiography and MRI (r(2) < 0.90, P < 0.0001). CONCLUSION: This study describes the technique and results of PV angiography and fluoroscopy. The study also demonstrates good correlation of PV ostial diameters by contrast venography and MRI. PV angiography can be used as an alternate to MRI or computed tomographic imaging, particularly when these tests are unavailable or are contraindicated in the patient.     

Life-threatening left atrial wall hematoma secondary to a pulmonary vein laceration: an unusual complication of catheter ablation for atrial fibrillation

Background: Several complications may occur during catheter ablation for atrial fibrillation (AF). We report an unusual case of left atrial wall hematoma without pericardial effusion secondary to a right inferior pulmonary vein (PV) laceration. The use of real-time transesophageal echocardiography (TEE) during the procedure can be useful for early detection of this potentially lethal complication.
Case report: A 49-year-old woman was referred for AF ablation. Her past medical history included severe systemic lupus with chronic renal failure treated with immunosuppressive and steroid drugs. A TEE-guided hybrid approach for AF ablation was performed with circular PV lesions and antrum and ostial electrical isolation. While performing the mitral isthmus line, the TEE showed a growing hematoma at the posterior left atrial wall. Rapidly, left atrium (LA) collapse associated with hemodynamic compromise occurred without any pericardial effusion. The patient was brought to the operating room. No pericardial effusion was seen at the time of surgery. The cardiac exploration showed a right inferior PV laceration. The visual inspection of the LA revealed thin and friable tissue. The patient survived. After 25 months of follow-up, she is still free from symptomatic AF.
Conclusions: Left atrial wall hematoma without pericardial effusion is a rare and life-threatening complication after catheter-based AF ablation. TEE is a valuable monitoring tool to accurately diagnose several acute complications and prompt rapid intervention.