UNASSIGNED: To assess feasibility, safety, and early efficacy of robotic-enhanced epicardial ablation (RE-EA) as first stage of a hybrid approach to patients with persistent (PsAF) and long-standing atrial fibrillation (LSAF).
UNASSIGNED: Single-center, retrospective analysis of patients with documented PsAF and LSAF who underwent RE-EA followed by catheter-guided endocardial ablation. Postoperatively, patients were monitored for major adverse events and underwent rhythm follow-up at 3 and 12 months.
UNASSIGNED: Between January 2021 and June 2023, we performed RE-EA in 64 patients (73.5% male, CHA2DS2-VASc 2.7 ± 1.6, BMI 34.1 ± 6.3 kg/m2). Mean AF preoperative duration and left atrial volume index were, respectively, 85 months and 47.5 mL/m2. Through the robotic approach, the intended lesion set was completed in all patients without cardiopulmonary bypass support, conversion to thoracotomy/sternotomy, blood transfusions, or perioperative mortality. The average LOS was 1.7 days, with only 1 patient requiring intensive care unit admission and >65% of patients discharged within 24 hours. At follow-up, 2 (3.1%) patients experienced new left pleural effusion or hemidiaphragm paralysis requiring treatment. There were no readmissions related to AF, stroke, thromboembolic events, or deaths. The mean interval between the epicardial and endocardial stages of the procedure was 5.9 months. Rhythm follow-up showed AF resolution in 73.4% and 71.9% of patients at 3 and 12 months, respectively.
UNASSIGNED: RE-EA is a feasible and safe, first-stage approach for the treatment of patients with PsAF and LSAF. It improves exposure of the intended targets, favors short hospital stay, and facilitates return to activity with satisfactory AF treatment in the short term.

OBJECTIVE: To analyze the relationship between the thickness of the left atrial posterior wall and the low and no voltage zones in the left atrial posterior wall in patients with atrial fibrillation (AF).
METHODS: 61 patients admitted to our cardiology department for AF and radiofrequency ablation of AF from January 1, 2020 to May 30, 2022 were enrolled according to inclusion and exclusion criteria. The atrial wall thickness was measured by CT scan. Baseline data, preoperative cardiac ultrasound data, preoperative biochemical parameters, low voltage zone (fibrotic zone) and no voltage zone (scar zone) in the left atrial posterior wall area, and various parameters of posterior left atrial wall thickness were collected.
RESULTS: The differences of the thickness between the upper, middle and lower mean levels of the left atrial posterior wall were statistically significant (P = 0.004). The results showed that body mass index was weakly positively correlated with the mean level of total left atrial posterior wall thickness (r = 0.426, P = 0.001) and was statistically significant. The remaining indices were positively or negatively correlated with the mean level of total left atrial posterior wall thickness, but none were statistically significant (P > 0.05).
CONCLUSIONS: Both left atrial posterior wall low-voltage zone and voltage-free zone were positively correlated with the mean total left atrial posterior wall thickness, and left atrial posterior wall low-voltage zone and voltage-free zone were significantly positively correlated. Body mass index was weakly positively correlated with total left atrial posterior wall thickness.

OBJECTIVE: The left atrial posterior wall (LAPW) can be a target for atrial fibrillation (AF) catheter ablation but is sometimes difficult to completely isolate due to the presence of endocardial-epicardial connections. We aimed to investigate the incidence and distribution of epicardial residual connections (epi-RCs) and the electrogram characteristics at epi-RC sites during an initial LAPW isolation.
METHODS: We retrospectively studied 102 AF patients who underwent LAPW mapping before and after a first-pass linear ablation along the superior and inferior LAPW (pre-ablation and post-ablation maps) using an ultra-high-resolution mapping system (Rhythmia, Boston Scientific).
RESULTS: Epi-RCs were observed in 41 patients (40.2%) and were widely distributed in the middle LAPW area and surrounding it. The sites with epi-RCs had a higher bipolar voltage amplitude and greater number of fractionated components than those without (median, 1.09 mV vs. 0.83 mV and 3.9 vs. 3.4 on the pre-ablation map and 0.38 mV vs. 0.27 mV and 8.5 vs. 4.2 on the post-ablation map, respectively; P < 0.001). Receiver operating characteristic analyses demonstrated that the number of fractionated components on the post-ablation map had a larger area under the curve of 0.847 than the others, and the sensitivity and specificity for predicting epi-RCs were 95.4% and 62.1%, respectively, at an optimal cutoff of 5.0.
CONCLUSIONS: Among the patients with epi-RCs after a first-pass LAPW linear ablation, areas with a greater number of fractionated components (> 5.0 on the post-ablation LAPW map) may have endocardial-epicardial connections and may be potential targets for touch-up ablation to eliminate the epi-RCs.

OBJECTIVE: Localization of the esophagus and the left atrium (LA) posterior wall thickness (LAPWT) should be taken into account when delivering radiofrequency energy. To validate the visualization of the esophagus and analyze LAPWT by ICE advanced into the LA in patients with atrial fibrillation (AF) undergoing ablation index (AI)-guided pulmonary vein (PV) isolation.
METHODS: In 73 patients (mean age, 68 ± 12; paroxysmal AF in 45), a 3-dimensional (3D) esophagus image was created with CARTO SoundstarⓇ and its location was compared with contrast esophagography saved in Carto UNIVU™. LAPWT adjacent to the esophagus was measured at 4 levels: left superior PV (LSPV), intervenous carina (IC), left inferior PV (LIPV), and LIPV bottom. A target AI value was 260 (25 W power) on the esophagus demonstrated by ICE.
RESULTS: All patients had the esophagus posterior to the left PV antrum. Creating a 3D esophagus and measurement of LAPWT with ICE was done without any complications. ICE esophagus image was completely overlapped with contrast esophagography. LAPWT (mm) was 2.8 (interquartile range, 2.5-3.2), 2.2 (1.9-2.5), 1.9 (1.8-2.1), and 2.1 (1.9-2.4) for LSPV, IC, LIPV, and LIPV bottom, respectively, while LA roof thickness was 3.2 (2.9-3.6) (P < 0.0001 by ANOVA). No residual conduction gap on the esophagus after the first circumferential PV isolation was found in 64 of 73 (88%) patients.
CONCLUSIONS: ICE inserted into the LA can reliably locate and display the esophagus and its relationship to the LA. LAPWT was the thinnest at the LIPV level. AI-guided ablation targeting at AI value 260 on the esophagus seemed to be effective.

When patients have symptomatic recurrent atrial tachyarrhythmias after 2 months following pulmonary vein antral isolation, a repeat ablation should be considered. Patients might present with isolated pulmonary veins posterior wall. In these patients, posterior wall isolation is extended, and non-pulmonary vein triggers are actively sought and ablated. Moreover, in those with non-paroxysmal atrial fibrillation or a known higher prevalence of non-pulmonary vein triggers, empirical isolation of the superior vena cava, coronary sinus, and/or left atrial appendage might be performed. In this review, we will focus on ablation of non-pulmonary vein triggers, summarizing our current approach for their mapping and ablation.

OBJECTIVE: 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.
METHODS: 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).
RESULTS: 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).
CONCLUSIONS: 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.

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.

Electroanatomical mapping is currently used to provide clinicians with information about the electrophysiological state of the heart and to guide interventions like ablation. These maps can be used to identify ectopic triggers of an arrhythmia such as atrial fibrillation (AF) or changes in the conduction velocity (CV) that have been associated with poor cell to cell coupling or fibrosis. Unfortunately, many factors are known to affect CV, including membrane excitability, pacing rate, wavefront curvature, and bath loading, making interpretation challenging. In this work, we show how endocardial conduction velocities are also affected by the geometrical factors of muscle thickness and wall curvature. Using an idealized three-dimensional strand, we show that transverse conductivities and boundary conditions can slow down or speed up signal propagation, depending on the curvature of the muscle tissue. In fact, a planar wavefront that is parallel to a straight line normal to the mid-surface does not remain normal to the mid-surface in a curved domain. We further demonstrate that the conclusions drawn from the idealized test case can be used to explain spatial changes in conduction velocities in a patient-specific reconstruction of the left atrial posterior wall. The simulations suggest that the widespread assumption of treating atrial muscle as a two-dimensional manifold for electrophysiological simulations will not accurately represent the endocardial conduction velocities in regions of the heart thicker than 0.5 mm with significant wall curvature.

BACKGROUND: It is unclear whether isolation of the left atrial posterior wall (LAPW) offers additional benefits over pulmonary vein antrum isolation (PVAI) alone in patients with persistent atrial fibrillation (AF).
OBJECTIVE: We sought to determine the impact of PVAI and LAPW isolation (PVAI+LAPW) versus PVAI alone on the outcome of ablation of persistent AF.
METHODS: During the first procedure, PVAI was performed in 20 patients (group 1), whereas in 32 patients (group 2), PVAI was extended to the left atrial (LA) septum and coronary sinus (CS), and isolation of the LAPW was targeted (ePVAI+LAPW). Isolation of the superior vena cava was achieved in both groups. All patients, regardless of arrhythmia recurrence, underwent a second procedure 3 months after the first procedure. In patients with reconnection of pulmonary veins or LAPW, reisolation was performed, and a third procedure was performed 3 months later to verify isolation. Patients entered follow-up only after PVAI (group 1) or PVAI+LAPW (group 2) isolation was proven.
RESULTS: At the 1-, 2-, and 3-year follow-up examinations, the rates of freedom from atrial tachyarrhythmia without use of an antiarrhythmic drug were 20%, 15%, and 10% in group 1 and 65%, 50%, and 40% in group 2, respectively (log-rank P < .001). The median recurrence-free survival time was 8.5 months (interquartile range 6.5-11.0) in group 1 and 28.0 months (interquartile range 8.5-32.0) in group 2.
CONCLUSIONS: Proven isolation of the LAPW provides additional benefits over PVAI alone in the treatment of persistent AF and improves procedural outcome at follow-up. However, the ablation strategy of ePVAI+LAPW is still associated with a significant high incidence of very late recurrence of atrial tachyarrhythmia.
BACKGROUND: \"Outcome of Atrial Fibrillation Ablation After Permanent Pulmonary Vein Antrum Isolation With or Without Proven Left Atrial Posterior Wall Isolation\" (LIBERATION). ClinicalTrials.gov Identifier: NCT01660100.