Left Atrial Posterior Wall Isolation Research Articles

Extended Pulmonary Vein Isolation: is it sufficient to achieve long-term sinus rhythm in octogenarian women with atrial fibrillation?

Abstract Background Atrial fibrillation (AF) is a disease of the elderly and women typically present with AF at an older age than men do. Moreover, they tend to experience more symptoms and post-ablation recurrences, have worse quality of life and increased risk of stroke and mortality. Objective We evaluated long-term efficacy of our standard ablation approach of extended pulmonary vein isolation (PVI) in octogenarian women undergoing their first AF ablation. Methods Consecutive female AF patients aged ≥80 years receiving their first catheter ablation at our center were included in the analysis. Our standard ablation approach at the first procedure includes PVI + empirical isolation of left atrial posterior wall (LAPW) and superior vena cava (SVC). Complete abolition of all potentials rather than decrease in amplitudes was the procedural end point. Patients were prospectively monitored at regular intervals for 3 years after the index procedure with event recorders, 12-lead ECG, cardiology evaluation at office visits and 7-day Holter monitoring. Results A total of 194 patients with mean age of 84.2±1.4 years were included in the analysis. Of the 194, 120 (61.8%) had non-paroxysmal AF. All received PVI+ isolation of LAPW and SVC. Acute procedural success was achieved in 100% of cases. At 3 years of follow-up, 24 (12.4%) patients remained in sinus rhythm; 22 on- and 2 off-antiarrhythmic drugs (AAD). All of the 23 patients had paroxysmal AF as their initial diagnosis. Of the 170 patients experiencing recurrence, 147 underwent repeat ablation. PV/PW/SVC reconnection was noted in only 6 (4.1%) patients at redo. Triggers originating from non-PV sites were targeted for ablation in all. At 1.5 years after the repeat procedure, 136 (92.5%) patients were in sinus rhythm; 131 off-AAD and 5 patients on-AAD. Conclusion Extended PVI including isolation of posterior wall and SVC was not sufficient to maintain long-term sinus rhythm in majority of octogenarian women, regardless of AF type. Moreover, non-PV triggers rather than PV reconnection was the major cause of recurrence in this subset of AF population. Funding Acknowledgement Type of funding source: None

Concomitant Pulmonary Vein and Posterior Wall Isolation Using Cryoballoon With Adjunct Radiofrequency in Persistent Atrial Fibrillation.

The aim of this multicenter, randomized, single-blind study was to prospectively evaluate the short-and long-term outcomes of pulmonary vein isolation (PVI) versus PVI with concomitant left atrial posterior wall isolation(PWI) using the cryoballoon in patients with symptomatic persistent/long-standing persistent atrial fibrillation (P/LSP-AF). Some studies have suggested a clinical benefit associated with PVI+PWI in patients with P/LSP-AF. However, there are limited safety and efficacy data on this approach using cryoballoon ablation. The immediate and long-term outcomes in patients with P/LSP-AF randomized to PVI (n=55) versus PVI+PWI (n=55) using the cryoballoon were prospectively examined. Baseline characteristics were similar. PVI was achieved in all patients (21 ± 11min). PWI was attained using 23 ± 8min of cryoablation. Adjunct radiofrequency ablation was required in 4 of 110 patients (7.3%) to complete PVI (3 ± 2min) and in 25 of 55 patients (45.5%) to complete PWI (4 ± 6min). Although left atrial dwell time (113 ± 31min vs. 75 ± 32min; p<0.001) and total procedure time (168 ± 34min vs. 127 ± 40min; p<0.001) were longer with PVI+PWI, this cohort required fewer intraprocedural cardioversions (89.1% vs. 96.4%; p=0.04). Adverse events occurred in 5.5% in each group (p=1.00). However, the incidence of recurrent atrial fibrillation at 12months was significantly lower with PVI+PWI (25.5% vs. 45.5%; p=0.028). Additionally, in a multivariate analysis, PVI+PWI emerged as a significant predictor of freedom from recurrent atrial fibrillation (odds ratio: 3.67; 95% confidence interval: 1.44 to 9.34; p=0.006). In patients with P/LSP-AF, PVI+PWI using the cryoballoon is associated with a significant reduction in atrial fibrillation recurrence, but similar safety, as compared with PVI alone.

Left atrial posterior wall isolation in conjunction with pulmonary vein isolation using cryoballoon for treatment of persistent atrial fibrillation (PIVoTAL): study rationale and design.

There is growing evidence in support of pulmonary vein isolation (PVI) with concomitant posterior wall isolation (PWI) for the treatment of patients with symptomatic persistent atrial fibrillation (persAF). However, there is limited data on the safety and efficacy of this approach using the cryoballoon. The aim of this multicenter, investigational device exemption trial (G190171) is to prospectively evaluate the acute and long-term outcomes of PVI versus PVI+PWI using the cryoballoon in patients with symptomatic persAF. The PIVoTAL is a prospective, randomized controlled study ( ClinicalTrials.gov : NCT04505163) in which patients with symptomatic persAF refractory/intolerant to ≥ 1 class I-IV antiarrhythmic drug, undergoing first-time catheter ablation, will be randomized to PVI (n = 183) versus PVI+PWI (n = 183) using the cryoballoon in a 1:1 fashion. The design will be double-blind until randomization immediately after PVI, beyond which the design will transform into a single-blind. PVI using cryoballoon will be standardized using a pre-specified dosing algorithm. Other empiric ablations aside from documented arrhythmias/arrhythmias spontaneously induced during the procedure will not be permitted. The primary efficacy endpoint is defined as AF recurrence at 12months, after a single procedure and a 90-day blanking period. Arrhythmia outcomes will be assessed by routine electrocardiograms and 7-14day ambulatory electrocardiographic monitoring at 3, 6, and 12months post-ablation. The PIVoTAL is a prospective, randomized controlled trial designed to evaluate the outcomes of PVI alone versus PVI+PWI using the cryoballoon, in patients with symptomatic persAF. We hypothesize that PVI+PWI will prove to be superior to PVI alone for prevention of AF recurrence.

Efficacy of an Adjunctive Electrophysiological Test-Guided Left Atrial Posterior Wall Isolation in Persistent Atrial Fibrillation Without a Left Atrial Low-Voltage Area.

Electrical remodeling precedes structural remodeling. In adjunctive left atrial (LA) low-voltage area (LVA) ablation to pulmonary vein isolation of atrial fibrillation (AF), LA areas without LVA have not been targeted for ablation. We studied the effect of adjunctive LA posterior wall isolation (PWI) on persistent AF without LA-LVA according to electrophysiological testing (EP test). We examined consecutive patients with persistent AF with (n=33) and without (n=111) LA-LVA. Patients without LA-LVA were randomly assigned to EP test-guided (n=57) and control (n=54) groups. In the EP test-guided group, an adjunctive PWI was performed in those with positive results (PWI subgroup; n=24), but not in those with negative results (n=33). The criteria for positive EP tests were an effective refractory period ≤180 ms, effective refractory period>20 ms shorter than the other sites, and/or induction of AF/atrial tachycardia (AT) during measurements. LVA ablation was performed in the patients with LA-LVA. During the follow-up period (62±33 weeks), the EP test-guided group had significantly lower recurrence rates (19%,11/57 versus 41%, 22/54, P=0.012) and higher Kaplan-Meier AF/AT-free survival curve rates than the control group (P=0.01). No significant differences in the recurrence and AF/AT-free survival curve rates between the PWI (positive EP test) and non-PWI (negative EP test) subgroups were observed. Therefore, PWI for positive EP tests reduced the AF/AT recurrence in the EP test-guided group. A stepwise Cox proportional hazard analyses identified EP test-guided ablation as a factor reducing the recurrence rate. The recurrence rates in the LA-LVA ablation group and EP test-guided group were similar. This pilot study proposed that an EP test-guided adjunctive PWI of persistent AF without LA-LVA potentially reduced AF/AT recurrences. The results suggest that there is an AF substrate in the LA with altered electrophysiological function even when there is no LA-LVA. Graphic Abstract: A graphic abstract is available for this article.

Posterior box isolation as an adjunctive ablation strategy with the second-generation cryoballoon for paroxysmal atrial fibrillation: a comparison with standard cryoballoon pulmonary vein isolation.

The purpose of the study was to evaluate the impact of left atrial posterior wall isolation (LAPWI) in addition to pulmonary vein isolation (PVI) vs PVI alone, performed using CB-A, in patients with PAF on a midterm follow-up of 12months. Eighty consecutive patients indicated to index cryoballoon ablation (CB-A) for the treatment of drug resistant PAF were included. The first 50 (62.5%) underwent PVI only, and the following 30 patients (37.5%) underwent LAPWI + PVI. Acute isolation was achieved in all PVs in both groups. The LAPW was successfully isolated in 29 out of 30 (97%) patients; in the remaining patient, adjunct radiofrequency ablation was required. The total procedure time and the mean fluoroscopy time were significantly shorter in patients who underwent PV isolation only (p < 0.001). The freedom from atrial fibrillation (AF) at 12months was not significantly different between the 2 groups (LAPW + PVI = 90% vs PVI = 88%) (log-rank p = 0.816). LAPW ablation in addition to PVI by the means of CB-A does not seem to reduce the risk of AF recurrence if compared with the standard PVI on a midterm follow-up of 12months.

P377Zero-fluoroscopy ablation with ultrasound-guided sheath insertion

Abstract Background Radiation exposure during catheter ablation procedures is a risk for both the patient and electrophysiology staff. Recently, the feasibility and effectiveness of zero-fluoroscopy ablation have been shown. However, ensuring a safe sheath insertion through the venous system toward the heart is a concern in catheter ablation using the zero-fluoroscopy technique. Purpose The objective of this study was to confirm feasibility and safety for zero-fluoroscopy ablation using ultrasound-guided sheath insertion. Methods Zero-fluoroscopy catheter ablation was performed in 220 patients (185 patients with atrial fibrillation (AF), 26 patients with supraventricular tachycardia (SVT), and nine patients with ventricular arrhythmias (VA)) using a 3-dimensional electro-anatomical mapping system, contact force monitoring, and intracardiac echocardiography (ICE) imaging. In all cases, ultrasound-guided sheath insertion was performed through the femoral vein. In 6 cases of VA, the retrograde approach through the femoral artery was performed with ICE imaging and contact-force monitoring. The endpoint of ablation for AF was pulmonary vein ablation in all cases and addition of left atrial posterior wall isolation in persistent AF cases. The endpoint of ablation for SVT and VA was noninducibility after ablation. Results The endpoints of ablation were achieved in all cases. The fluoroscopic time during ablation procedures was 0 seconds. There were two complications (one cardiac tamponade and one acute heart failure). There were no complications related to sheath insertion. Conclusions Zero-fluoroscopy catheter ablation with ultrasound-guided sheath insertion may be feasible and can be performed safely. This method eliminates exposure radiation safely, which is a concern of zero-fluoroscopy endocardial catheter ablation.

Residual potential at the epicardial left atrium after conventional left atrial posterior wall isolation for persistent atrial fibrillation: A case report.

Residual potential at the epicardial left atrium after conventional left atrial posterior wall isolation for persistent atrial fibrillation: A case report.

Epicardial adipose tissue affects the efficacy of left atrial posterior wall isolation for persistent atrial fibrillation.

BackgroundEpicardial adipose tissue (EAT) contributes to atrial fibrillation (AF). However, its impact on the efficacy of left atrial posterior wall isolation (LAPWI) is unclear.MethodsForty‐four nonparoxysmal AF patients underwent LAPWI after pulmonary vein isolation. EAT overlap on LAPWI was assessed by fusing computed tomography images with electro‐anatomical mapping.ResultsDuring the 21 ± 7 months of follow‐up, AF recurred in 10 patients (23%). The total and left atrial EAT volumes were 113 ± 36 and 33 ± 12 cm3, respectively. No differences were found between the AF‐free and AF‐recurrent groups regarding EAT volume. The EAT overlaps on LAPWI lines and LAPWI area were 1.2 ± 1.0 and 0.5 ± 0.9 cm2 respectively. Although no difference was found between groups regarding the EAT overlap on LAPWI area, the AF‐free group had a significantly larger EAT overlap on LAPWI lines (1.4 ± 1.0 vs 0.6 ± 0.6 cm2, P = .014). Multivariate analysis identified EAT overlap on LAPWI lines as an independent predictor of AF recurrence (hazard ratio: 0.399, 95% confidence interval: 0.178‐0.891, P = .025). Kaplan‐Meier analysis revealed that, during follow‐up, 92% of the large EAT overlap group (≥1.0 cm2) and 58% of the small EAT overlap group (<1.0 cm2) remained AF‐free (P = .008).ConclusionsEAT overlap on LAPWI lines is related to a high AF freedom rate. Direct radiofrequency application to EAT overlap may be necessary to suppress AF.

High-power, short-duration atrial fibrillation ablations using contact force sensing catheters: Outcomes and predictors of success including posterior wall isolation

Little is known about the long-term outcomes and predictors of success of high-power, short-duration (HPSD) contact force (CF) atrial fibrillation (AF) ablations. The purpose of this study was to determine long-term freedom from AF and predictors of freedom from AF for 50-W, 5- to 15-second CF ablation. We examined 4-year outcomes and predictors of freedom from AF after AF ablation for 1250 consecutive patients undergoing HPSD CF ablations. Patient demographics were age 66.6 ± 10.5 years, female 30.9%, left atrial (LA) size 4.26 ± 0.66 cm, paroxysmal AF 35.7%, persistent AF 56.6%, and longstanding AF 7.7%. Initial ablation times were procedure 114.2 ± 45.9 minutes, fluoroscopy 15.5 ± 11.5 minutes, and total radiofrequency 20.6 ± 7.7 minutes. TactiCath was used in 47.7%, SmartTouch in 52.3%, and posterior wall isolation (PWI) was performed in 34%. Four-year freedom from AF after multiple ablations were paroxysmal AF 87.0%, persistent AF 71.9%, and longstanding AF 64.9%. Single procedure success was 74.9% for TactiCath, 64.7% for SmartTouch (P <.001), and 73.0% for no PWI vs 58.9% for PWI (P <.0001). PWI did not change outcomes for paroxysmal AF but had worse outcomes for nonparoxysmal AF. Multivariate analysis showed 6 independent predictors of worse outcome after initial ablation: older age (P = .014), female gender (P <.0001), persistent AF (P = .0001), larger LA size (P <.001), PWI (P = .049), and use of SmartTouch vs TactiCath catheter (P= .007). Redo ablations were performed in 13.8%, and the outcome was better when more veins had reconnected after the initial ablation and when AF was paroxysmal. Analysis revealed 6 independent predictors of outcome for HPSD CF. At redo ablations, the outcome was better if more veins had reconnected and could be re-isolated.

SAFETY AND EFFICACY OF A CONVERGENT HYBRID PROCEDURE USING CRYO AS ENDOCARDIAL ENERGY SOURCE FOR THE TREATMENT OF PERSISTENT AND LONGSTANDING PERSISTENT ATRIAL FIBRILLATION

Catheter-based endocardial ablation has limited efficacy for persistent and long-standing persistent atrial fibrillation (PersAF). Convergent hybrid procedures where endocardial ablation is augmented by epicardial left atrial posterior wall isolation have reported increased success. Most published

One-year outcomes after pulmonary vein isolation plus posterior wall isolation and additional non-pulmonary vein trigger ablation for persistent atrial fibrillation with or without contact force sensing: a propensity score-matched comparison.

Whether or not pulmonary vein isolation (PVI) plus left atrial posterior wall isolation (PWI) using contact force (CF) sensing improves the ablation outcome for persistent atrial fibrillation (AF) is unclear. This study compared the outcome of PVI plus PWI and additional non-PV trigger ablation for persistent AF with/without CF sensing. This retrospective cohort study analyzed 148 propensity score-matched persistent AF patients (median duration of persistent AF, 8months (interquartile range, 3-24months); left atrial diameter, 43 ± 7mm) undergoing PVI plus PWI and ablation of non-PV triggers provoked by high-dose isoproterenol, including 74 with CF-sensing catheters (CF group) and 74 with conventional catheters (non-CF group). PVI plus PWI with no additional ablation but cavotricuspid isthmus ablation was performed without non-PV triggers in 48 CF patients (65%) and 54 non-CF patients (73%) (P = 0.38). In all other patients, we performed additional ablation of provoked non-PV triggers. The Kaplan-Meier estimate of the rate of freedom from atrial tachyarrhythmia recurrence off antiarrhythmic drugs at 12months after the single procedure was higher in the CF group than in the non-CF group (85 vs. 70%, log-rank P = 0.030). A multivariable analysis revealed that using CF sensing and non-inducibility of AF from a non-PV trigger after PVI and PWI were significantly associated with a reduced rate of atrial tachyarrhythmia recurrence. Compared with non-CF sensing, PVI plus PWI and additional non-PV trigger ablation using CF-sensing catheters for persistent AF can reduce the rate of atrial tachyarrhythmia recurrence.

Clinical impact of rapid ventricular pacing on the left atrial posterior wall isolation by a cryoballoon application: a randomized controlled trial.

Rapid ventricular pacing (RVP) was reported to improve the cooling effects of the cryoballoon (CB). The aim of this study was to investigate the safety and efficacy of RVP for left atrial posterior wall isolation (PWI) by the CB. One hundred consecutive patients (males 80, mean age 63 ± 10 years) with persistent atrial fibrillation underwent left atrial roof (LA-RB) and bottom block line (LA-BB) creation by CB to achieve PWI. Patients were randomized into two groups according to whether they underwent PWI with (RVP group, n = 50) or without RVP (control group, n = 50). The nadir CB temperature (NCT) during the LA-RB and LA-BB creation was significantly lower in the RVP group than control group (LA-RB - 45.7 °C and - 43.9 °C, p < 0.001, and LA-BB - 42.4 °C and - 40.0 °C, p < 0.001). The success rate of the LA-RB creation was significantly higher in the RVP group than the control group (98% vs. 88%, p = 0.039), however, there were no significant differences regarding the LA-BB creation (66% vs. 52%, p = 0.15) and PWI (66% vs. 50%, p = 0.1) between the two groups. The PWI success rate did not differ whether CB freezing was prematurely terminated due to an excessive luminal esophageal temperature (LET) drop in the RVP group (65.8% vs. 66.7%, respectively, p = 0.96). RVP significantly decreased the NCT during the CB application resulting in the significant improvement of success rate of the LA-RB. The advantage of RVP in terms of the accomplishing PWI was not affected even when the CB freezing was prematurely terminated due to an excessive LET drop.

Thoracoscopic Pulmonary Vein and Left Atrial Posterior Wall Isolation Combined with Left Atrial Appendage Resection in Patients with Long-Standing Persistent Atrial Fibrillation.

ObjectiveTo evaluate the efficacy and safety of a modified technique for totally thoracoscopic left atrial posterior wall and pulmonary vein isolation in patients with long-standing persistent atrial fibrillation.MethodsFrom April 2017 to December 2018, we included in this study 28 consecutive patients who underwent thoracoscopic left atrial posterior wall and pulmonary vein radiofrequency isolation combined with left atrial appendage resection. We used a device with irrigated electrodes (Medtronic Cardioblate Gemini-s). The original surgical technique “GALAXY” proposed by Doty in 2012 was modified. The number of ablations was significantly increased, and frequent position changing of the ablation device and change of device angulation were added.ResultsSinus rhythm was restored in all patients. There was no operative mortality, no myocardial infarction, and no stroke or transient ischemic attack. One patient required sternotomy and another survived left anterolateral thoracotomy due to bleeding. A 180-day follow-up (24-hour Holter monitoring) revealed no sign of recurrence of atrial fibrillation or other supraventricular arrhythmia in any patient. Mean follow-up was nine months (range: 6-16 months). At the last follow-up, 26 patients (92,9%) were in sinus rhythm (24-hour Holter monitoring).ConclusionA frequent ablation device position changing during the surgery makes it possible to achieve complete left atrial posterior wall and pulmonary veins isolation. An increased number of applications allows to avoid a false positive transmural damage assessment showed by impedance drop. Also, frequent position changing of the ablation device and increased number of applications do not affect the number of postoperative complications.

Left atrial appendage isolation during ablation in the interatrial septum: Rapid recognition by continuous monitoring of appendage electrograms

Extensive atrial ablation in the setting of atrial fibrillation (AF) and atrial tachycardia (AT) can affect interatrial connections. A 76-year-old man with a history of tachycardia-induced cardiomyopathy and nine ablation procedures for AF/AT over 15 years presented with highly symptomatic recurrent AT. Previous ablation lesions included pulmonary vein isolation, left atrial posterior wall isolation, mitral isthmus line, cavotricuspid isthmus line, and the ablation of areas of fractionated electrograms. Electroanatomical mapping found the pulmonary veins and the left atrial posterior wall to be silent, as was the posterior interatrial septum and the mitral isthmus area. Activation mapping showed progression of electrograms in the left atrial appendage (LAA) from the septal aspect posteriorly, and in the coronary sinus from proximal to distal; implying the existence of a septal circuit, where extensive fractionation was noted. This was targeted, while monitoring conduction into the LAA using a multielectrode catheter. Ablation led to prompt termination of tachycardia and simultaneous LAA isolation. Immediate cessation of ablation led to recovery of conduction into LAA. Additional lesions in the interatrial septum were required to render the tachycardia noninducible, accompanied by temporary isolation of LAA. The ablation lesion sets employed while ablating AF and left AT can block many interatrial pathways, rendering conduction dependent on muscle bundles in the interatrial septum and, therefore, vulnerable to block by lesions in this area. LAA isolation has been associated with high incidence of LAA thrombus formation and stroke despite oral anticoagulation. Continuous observation of LAA electrograms during ablation can help to avoid this complication.

Safety and efficacy outcomes of left atrial posterior wall isolation compared to pulmonary vein isolation and pulmonary vein isolation with linear ablation for the treatment of persistent atrial fibrillation

Pulmonary wall isolation (PWI) is increasingly used as an adjunctive lesion set to compliment pulmonary vein isolation (PVI), especially in patients with persistent atrial fibrillation (AF). The objective was to compare outcomes of catheter ablation in patients with persistent AF undergoing PVI with and without adjunctive PWI. We performed a retrospective study of 558 patients who underwent de novo and repeat ablation for persistent AF. Subjects were matched using propensity score adjustments. Outcomes were freedom from recurrent atrial arrhythmia and adverse events. Among 558 patients who underwent ablation for persistent AF, 78 (14%) underwent PVI + PWI, 255 (46%) underwent PVI, and 225 (40%) underwent PVI + linear ablation. Stratified logistic regression analysis with propensity matching revealed higher odds of recurrent arrhythmia with PVI + PWI when compared to PVI (odds ratio [OR] 2.25, 95% CI 1.08-4.69, P = .030) and when compared to PVI + linear (OR 2.31, 95% CI 1.01-5.28, P = .048). Within the PVI + PWI group, 57.7% of subjects were in normal sinus rhythm at 6 months compared to 73.9% and 72.2% in PVI and PVI + linear groups, respectively. Adverse events were rare, with 19 events total identified across all groups. PVI + PWI does not appear to be as effective as PVI or PVI + linear ablation in reducing the recurrence of arrhythmia within 6 months of the index procedure in patients with persistent AF. A prospective, randomized controlled trial comparing these ablation techniques is needed to clarify the role of extensive substrate modification for treatment of persistent AF. PWI is increasingly used as an adjunctive lesion set to compliment PVI in patients with persistent AF. We performed a retrospective study of 558 patients who underwent de novo and repeat ablation for persistent AF to compare the outcomes between PVI with and without adjunctive PWI. We found an increased incidence in recurrence of AF and other atrial arrhythmias at 6 months in the PVI + PWI cohort compared to PVI with or without additional linear ablation. A prospective, randomized controlled trial comparing these ablation techniques is needed to clarify the role of extensive substrate modification for treatment of persistent AF.

The effect of esophageal cooling on esophageal injury during radiofrequency catheter ablation of atrial fibrillation.

Catheter ablation of atrial fibrillation (AF) may lead to collateral damage to the esophagus. We tested the hypothesis that luminal esophageal temperature (LET)-guided esophageal cooling might reduce the incidence of esophageal thermal lesions (ETL). Seventy-six patients from August 2015 to March 2017 with paroxysmal or persistent AF underwent a first-time catheter ablation procedure with or without LET-guided active esophageal cooling through an orogastric tube placed in the esophagus. Esophageal cooling occurred if and only if LET exceeded 0.5°C from baseline while ablating the LA posterior wall. All patients underwent esophagogastric endoscopy the next day. Of the 76 patients studied, 38 (50%) patients underwent esophageal cooling. Baseline characteristics of the non-cooled and cooled groups were comparable. Of these, 59% of patients had ETL. There was a non-significant trend for more severe lesions (grades 3, 4) in the non-cooled group (29% vs. 13.5%, p = 0.10). Average power delivered on the left atrial posterior wall (27 ± 1.8W vs. 27 ± 3.8W, p = 0.34) and average force of contact (10.1g vs. 9.8g, p = 0.38) were similar in both groups while more time was spent ablating on the posterior wall in the non-cooled group (24.6 ± 7.3min vs. 20.4 ± 5.9min, p = 0.014). In a multivariate analysis, esophageal cooling had no significant effect on the esophageal lesion grade post-ablation. The incidence of ETL in patients undergoing left atrial posterior wall isolation is substantial. Our method of esophageal cooling did not decrease the incidence of ETL. There was a non-significant trend toward fewer severe lesions with cooling, but one cannot conclude the value of cooling from this pilot study.

Left atrial posterior wall isolation affects complex fractionated atrial electrograms in persistent atrial fibrillation.

BackgroundThe impact of left atrial posterior wall isolation (LAPWI) on the complex fractionated atrial electrogram (CFAE) is unknown.Methods CFAE mapping was performed before and after LAPWI in 46 patients with persistent atrial fibrillation (AF).Results LAPWI decreased both the variable (fractionated index ≤ 120 ms; from 60 ± 4 cm2 to 50 ± 4 cm2, P < 0.001) and continuous (fractionated index ≤ 50 ms; from 4.2 ± 1.0 cm2 to 3.5 ± 0.9 cm2, P = 0.036) CFAE areas. Especially, the CFAE areas on the bottom and roof walls of the left atrium and on the posterior and bottom walls of the right atrium significantly decreased after LAPWI. The distribution of variable CFAE areas was not different between the AF‐recurrence (n = 9) and AF‐free (n = 37) groups before LAPWI; however, it was larger in the anterior and septal walls of the right atrium in the AF‐recurrence group than in the AF‐free group after LAPWI (anterior wall, 8% ± 2% vs 5% ± 1%, P = 0.048; septal wall, 23% ± 4% vs 16% ± 1%, P = 0.043). The distribution of continuous CFAE areas on the bottom wall of the right atrium was larger in the AF‐recurrence group than in the AF‐free group both before LAPWI (30% ± 20% vs 4% ± 2%, P = 0.008) and after LAPWI (25% ± 25% vs 3% ± 1%, P = 0.027).Conclusions LAPWI decreased the CFAE areas and affected their distribution, which contributed to AF recurrence.

The rationale for isolation of the left atrial pulmonary venous component to control atrial fibrillation: A review article

Catheter ablation of persistent atrial fibrillation (AF) is an evolving field. In this review, we discuss the rationale for isolation of the pulmonary venous component of the left atrium to control AF. The review describes the embryologic origin of this component and makes the important distinction between the true posterior wall and the pulmonary venous component, which forms the dome of the left atrium. Studies that have examined the role of left atrial posterior wall isolation in AF ablation have loosely referred to the pulmonary venous component as the posterior wall. We critically reexamine this nomenclature and provide a sound argument underpinned by fundamental anatomic considerations, a clear understanding of which is critical to the operator. We discuss the various techniques used in isolating this region and review the outcome data of studies targeting this region in AF ablation.

Clinical investigation of esophageal injury from cryoballoon ablation of persistent atrial fibrillation.

The cryoballoon (CB) can be utilized for extra pulmonary vein (PV) ablation such as for a left atrial (LA) posterior wall (LAPW) isolation. However, scrutiny of the esophageal injuries during the LAPW isolation has never been performed. We sought to thoroughly investigate the esophageal lesions (ELs) and gastric hypomotility (GH) caused by an LAPW isolation using a CB. A total of 101 persistent atrial fibrillation patients who underwent an LAPW isolation using a CB were enrolled. The CB was applied on the roof and bottom area of the LAPW after a PV isolation. The luminal esophageal temperature (LET) was monitored by a thermistor probe during the CB applications. When the LET reached 15°C, the freezing application was prematurely interrupted. Esophagogastroscopy was performed on the next day following the ablation. All PVs were successfully isolated in all patients. A successful LAPW isolation solely with CB ablation was performed in 72 (71.3%) patients. Cryofreezing applications were prematurely interrupted due to low LETs in 49 (48.5%) patients predominantly during the LA bottom line ablation. ELs and GH were observed in 11 (10.9%) and 16 patients (15.8%), respectively. The nadir LET tended to be lower in patients with ELs and GH than in those without (ELs: 14.8 ± 4.5°C vs 17.4 ± 6.0°C, P=0.17; GH: 15.5 ± 4.5°C vs 17.5 ± 6.1°C, P=0.23, respectively). Esophageal complications such as ELs and GH occur during the LAPW isolation with a CB. There was no reliable predictor of those adverse events.

Theuse of an esophageal catheter to check the results of left atrial posterior wall isolation in the treatment of atrial fibrillation.

Left atrial posterior wall isolation (LAPWI) via catheter, surgical, and hybrid techniques is a promising treatment for persistent atrial fibrillation (PersAF). We investigated whether confirmation of LAPWI can be achieved using an esophageal pacing and recording electrode. Patients undergoing PersAF ablation with the intention to achieve LAPWI were enrolled. Two approaches to LAPWI were tested: (1) ablation using endocardial catheter ablation only, and (2) "Staged Hybrid" ablation with thoracoscopic epicardial ablation, followed by endocardial left atrial electrophysiological study and catheter ablation where necessary. Patients enrolled in the study all required further catheter ablation to achieve LAPWI in this group. In both the groups, esophageal recording and esophageal pacing was performed at the start of mapping and electrophysiological study and compared with endocardial electrophysiological findings. This was repeated at the end of the procedure. Twenty patients (16M, four F) were studied. Endocardial electrophysiological study showed that in none of the cases was the posterior left atrial wall electrically isolated at the start of the study. One patient with Barrett's esophagus failed to sense or pace from the esophagus at any point in the study. In the remaining 19/19, esophageal pacing captured the atrial rhythm at the start of the procedure. LAPWI was then achieved in 17/19 using endocardial catheter ablation; retesting at this point showed sensing and capture of the atrium from the esophagus was abolished. In the remainder sensing and capture persisted. Esophageal pacing can be used to confirm or refute electrical isolation of the left atrial posterior wall.