Left atrial roof region ablation using a visually guided laser balloon.

Balloon-based catheter ablation including visually guided laser balloon (VGLB) has been adopted a first line therapeutic strategy for the patients with atrial fibrillation (AF). Recently, the roof area ablation beyond pulmonary vein (PV) isolation (PVI) using cryoballoon has been described as an effective therapy for the patients with persistent AF. However, the roof area ablation performed with a VGLB remains unknown. In this case, we report the case of roof area ablation for the patient with persistent AF using a VGLB.

Proactive esophageal cooling during laser cardiac ablation: A computer modeling study.

BACKGROUND AND OBJECTIVES: Laser ablation is increasingly used to treat atrial fibrillation (AF). However, atrioesophageal injury remains a potentially serious complication. While proactive esophageal cooling (PEC) reduces esophageal injury during radiofrequency ablation, the effects of PEC during laser ablation have not previously been determined. We aimed to evaluate the protective effects of PEC during laser ablation of AF by means of a theoretical study based on computer modeling. METHODS: Three-dimensional mathematical models were built for 20 different cases including a fragment of atrial wall (myocardium), epicardial fat (adipose tissue), connective tissue, and esophageal wall. The esophagus was considered with and without PEC. Laser-tissue interaction was modeled using Beer-Lambert's law, Pennes' Bioheat equation was used to compute the resultant heating, and the Arrhenius equation was used to estimate the fraction of tissue damage (FOD), assuming a threshold of 63% to assess induced necrosis. We modeled laser irradiation power of 8.5 W over 20 s. Thermal simulations extended up to 250 s to account for thermal latency. RESULTS: PEC significantly altered the temperature distribution around the cooling device, resulting in lower temperatures (around 22°C less in the esophagus and 9°C in the atrial wall) compared to the case without PEC. This thermal reduction translated into the absence of transmural lesions in the esophagus. The esophagus was thermally damaged only in the cases without PEC and with a distance equal to or shorter than 3.5 mm between the esophagus and endocardium (inner boundary of the atrial wall). Furthermore, PEC demonstrated minimal impact on the lesion created across the atrial wall, either in terms of maximum temperature or FOD. CONCLUSIONS: PEC reduces the potential for esophageal injury without degrading the intended cardiac lesions for a variety of different tissue thicknesses. Thermal latency may influence lesion formation during laser ablation and may play a part in any collateral damage.

Preclinical evaluation of semi-automated laser ablation for pulmonary vein isolation: A comparative study.

INTRODUCTION: Visually-guided laser balloon ablation (VGLA) currently requires careful manual rotation of the laser to create overlapping lesions. A novel semi-automated VGLA may reduce ablation times and lesion gaps. We aimed to compare semi-automated (SA) VGLA to that of manual (MN) VGLA. METHODS: Acute: Nine swine underwent right superior pulmonary vein isolation (PVI) using either SA (n = 3, 13-18 W), MN (n = 3, 8.5-12 W), or radiofrequency (RF, n = 3, 25-40 W) and were killed acutely. Chronic: 16 swine, underwent PVI using either SA (n = 8, 15 W) or MN (n = 8, 10 W), and were survived for 1 month before being killed. All hearts were then submitted for pathological evaluation. RESULTS: Acute: PVI was successful in all 9/9 swine with lesion counts significantly lower in the SA arm (5.3 ± 5.9, 33.7 ± 10.0, and 28.0 ± 4.4 in SA, MN, and RF arms; p = .007 for SA and MN). At necropsy, circumferentiality and transmurality were 98% and 94% in SA, 98% and 80% in MN, and 100% and 100% in RF arms. A single steam pop was noted on sectioning in the SA arm swine and occurred in the high dose (18 W) strategy. Chronic: PVI was acutely successful in 16/16 swine with no difference in PVI durability rates (62.5% vs. 75.0%), lesion transmurality (95.8 ± 17.4% vs.91.9 ± 25.9%), and circumferentiality (95.8 ± 6.6% vs. 94.8 ± 6.3%) between SA and MN arms. Catheter use time and lesion counts were lower in the SA arm compared to the MN arm (11.5 ± 12.7 vs. 21.8 ± 3.8 min, p = .046 and 4.8 ± 3.83 vs. 35.4 ± 4.4, p < .001). CONCLUSION: Motor-assisted semi-automated laser balloon ablation can improve upon procedural efficiency by reducing ablation time.

Atrial fibrillation recurrences during the blanking period after catheter ablation with the laser balloon technique.

INTRODUCTION: Regardless of the catheter ablation (CA) for atrial fibrillation (AF) strategy, the role of early recurrences during the blanking period (BP) is still unclear. Our aim was to evaluate atrial tachyarrhythmias (ATAs) recurrences during the BP after CA with the laser-balloon (LB) technique. METHODS: Consecutive patients undergoing LBCA were enrolled. Primary outcome of the study was the overall crude ATA recurrence rate during the BP. ATA recurrences after the BP and in-hospital readmissions during the BP were deemed secondary outcomes. RESULTS: Two hundred and twenty-four patients underwent CA with the LB. Median age was 63.0 (55.5-69.5) years and 74.1% were males. 28.6% were persistent AF patients, and 34.8% of patients were followed up with a loop recorder. 15.6% of patients experienced at least an ATA recurrence during the BP. Male sex, chronic heart failure, persistent AF, and recurrences during the BP were found to be associated with long-term ATA recurrences. Recurrences during the BP remained associated with the outcome of interest at multivariate analysis (hazard ratio [HR] = 12.393, 95% confidence interval [95% CI] = 3.699-41.865, p < .001). An association over time was found between early and late recurrences, with 73.7%, 45.5%, and 10.8% of patients presenting with recurrences at 1-, 2-, and 3-month follow-up being free from recurrences after the BP, respectively. 8.0% of patients were readmitted during the BP: 4.5% for AF electrical cardioversion, and 1.8% for CA of other atrial arrhythmias; no redo CA was performed. CONCLUSION: After adjusting for confounders, ATA recurrences during the BP represent the most significant predictor of ATA recurrences after the BP, regardless of AF pattern.

Durability of pulmonary vein isolation for atrial fibrillation: a meta-analysis and systematic review.

AIMS: Pulmonary vein isolation (PVI) plays a central role in the interventional treatment of atrial fibrillation (AF). Uncertainties remain about the durability of ablation lesions from different energy sources. We aimed to systematically review the durability of ablation lesions associated with various PVI-techniques using different energy sources for the treatment of AF. METHODS AND RESULTS: Structured systematic database search for articles published between January 2010 and January 2023 reporting PVI-lesion durability as evaluated in the overall cohort through repeat invasive remapping during follow-up. Studies evaluating only a proportion of the initial cohort in redo procedures were excluded. A total of 19 studies investigating 1050 patients (mean age 60 years, 31% women, time to remap 2-7 months) were included. In a pooled analysis, 99.7% of the PVs and 99.4% of patients were successfully ablated at baseline and 75.5% of the PVs remained isolated and 51% of the patients had all PVs persistently isolated at follow-up across all energy sources. In a pooled analysis of the percentages of PVs durably isolated during follow-up, the estimates of RFA were the lowest of all energy sources at 71% (95% CI 69-73, 11 studies), but comparable with cryoballoon (79%, 95%CI 74-83, 3 studies). Higher durability percentages were reported in PVs ablated with laser-balloon (84%, 95%CI 78-89, one study) and PFA (87%, 95%CI 84-90, 2 studies). CONCLUSION: We observed no significant difference in the durability of the ablation lesions of the four evaluated energies after adjusting for procedural and baseline populational characteristics.

Pulmonary Vein Stenosis After Catheter Ablation of Atrial Fibrillation Using a Cryoballoon, Hot Balloon, or Laser Balloon.

BACKGROUND: Pulmonary vein stenosis (PVS) after PV isolation (PVI) for atrial fibrillation (AF) is a severe complication that requires angioplasty. This study aimed to compare the reduction of the cross-sectional PV area (PVA) and the incidence of PVS after cryoballoon (CB)-PVI, hot balloon (HB)-PVI, or laser balloon (LB)-PVI.Methods and Results: A total of 320 patients who underwent an initial catheter ablation procedure for AF using a CB, HB, or LB in 2 hospitals were included. They underwent contrast-enhanced multidetector CT before and 3 months after the procedure. In all 4 PVs, the reduction in PVA was more significant in the LB group than in the CB or HB groups, respectively. Moderate (50-75%) and severe (>75%) PVS were observed in 5.3% and 0.5% of the PVs, respectively. Although moderate PVS was more frequently observed in the LB group than in the CB or HB groups (8.2%, 3.8%, and 5.0%; P=0.03), the incidence of severe PVS was similar in the LB, CB, and HB groups (0.3%, 0.5%, and 1.0%; P=0.46). Symptomatic PVS requiring intervention occurred in 1 (0.3%) patient. CONCLUSIONS: Although the reduction in cross-sectional PVA and the incidence of moderate PVS after LB-PVI was more significant than after CB-PVI or HB-PVI, it rarely led to severe PVS. Symptomatic PVS requiring intervention was rare after the balloon ablation of AF.

Feasibility of energy-guided short duration protocol of laser balloon based pulmonary vein isolation for atrial fibrillation (EG-Laser Study).

BACKGROUND: Laser balloon-based pulmonary vein isolation (LB-PVI) is available for atrial fibrillation (AF) ablation. The lesion size depends on laser energy; however, the default protocol is not an energy-based setting. We hypothesized that an energy-guided (EG) short-duration protocol may be an alternative to shorten the procedure time without affecting efficacy and safety. METHODS: We evaluated the efficacy and safety of the EG short-duration protocol (EG group) (target energy 120 J/site [12W/10s; 10W/12s; 8.5W/14s; 5.5W/22s]) compared with the default protocol (control group) (12W/20s; 10W/20s; 8.5W/20s; 5.5W/30s). RESULTS: A total of 52 consecutive patients (EG: n = 27 [103veins] and control: n = 25 [91veins]) undergoing LB-PVI (64 ± 10 years, 81% male, 77% paroxysmal) were enrolled. The EG group had a shorter total time in the pulmonary vein (PV) (43.0 ± 13.9 min vs. 61.1 ± 16.0 min, p < .0001), a shorter total laser application time (1348 ± 254 sec vs. 2032 ± 424 sec, p < .0001), and lower total laser energy (12455 ± 2284J vs. 18084 ± 3746J, p < .0001). There was no difference in the total number of laser applications (p = 0269) or first-pass isolation (p = .725). Acute reconduction was identified only in one vein in the EG. No significant differences were observed in the incidence of pinhole rupture (7.4% vs. 4%, p = 1.000) or phrenic nerve palsy (3.7% vs. 12%, p = .341). During a mean follow-up of 13.5 ± 6.1 months, Kaplan-Meier analysis revealed no significant difference in atrial tachyarrhythmia recurrence (p = .227). CONCLUSION: LB-PVI with the EG short-duration protocol may be achieved in a shorter procedure time to avoid deterioration of efficacy and safety. The EG protocol is feasible as a novel point-by-point manual laser-application approach.

Comparison of maximum-sized visually guided laser balloon and cryoballoon ablation.

Balloon ablation therapy has recently been used for atrial fibrillation (AF) ablation. Laser balloons possess the property in which the balloon size can be changed. Standard laser balloon ablation (Standard LBA) was followed by additional ablation using a maximally extended balloon (Extended LBA) and its lesion characteristics were compared to cryoballoon ablation (CBA), another balloon technology. From June 2020 to July 2021, patients with paroxysmal AF who underwent an initial pulmonary vein (PV) isolation were enrolled. Sixty-five patients with paroxysmal AF were included, 32 in the LBA and 33 in the CBA group. To measure the isolated surface area after the ablation procedures, left atrial voltage mapping was performed after Standard LBA, Extended LBA, and CBA. The baseline patient characteristics did not differ between LBA and CBA. Extended LBA could successfully increase the isolated area more than Standard LBA for all four PVs. Compared to CBA, the isolated area of both superior PVs was significantly greater with Extended LBA (left superior PV: 8.5 ± 2.1 vs 7.3 ± 2.4, p = 0.04, right superior PV: 11.4 ± 3.7 vs 8.7 ± 2.7, p < 0.01), and thus the non-isolated posterior wall (PW) was smaller (8.5 ± 3.4 vs 12.4 ± 3.3, p < 0.01). Nevertheless, changes in the cardiac injury markers were significantly lower with LBA than CBA. There was no significant correlation between the cardiac injury level and isolated area in both groups. In conclusion, Extended LBA exhibited a significantly greater isolation of both superior PVs and resulted in a smaller non-isolated PW, but the cardiac injury markers were significantly suppressed as compared to CBA.

Feasibility and safety of laser balloon pulmonary vein isolation in patients with prior left atrial appendage occlusion device implantation.

INTRODUCTION: With the increasing adoption of left atrial appendage occlusion (LAAO) procedures and the eligibility of patients for pulmonary vein isolation (PVI) post device placement, we examined the feasibility and safety of laser balloon (LB) for PVI in patients with prior LAAO. METHODS: We retrospectively examined consecutive patients with paroxysmal or persistent, drug-resistant atrial fibrillation (AF) who underwent LB PVI, after Watchman FLX device implantation at Rush University Medical Center between January 2020 and December 2021. RESULTS: Seven patients (four persistent and three paroxysmal) with a mean age of 64 ± 11 years, predominantly male sex (86%), were included in the study. Two (29%) patients had prior cryoablation PVI with recurrence of AF. The mean CHA2 DS2 VASc is 2.6 ± 0.5 and the mean HAS-BLED score is 3.4 ± 0.8. The mean follow-up duration was 10 ± 7 months. The mean duration between Watchman FLX device implantation and LB PVI was 592 days. Acute first pass left pulmonary vein (PV) isolation was achieved in 100% of the procedures. There were no periprocedural complications such as death, pericardial tamponade or effusion, phrenic nerve injury, PV stenosis, device perforation or embolization, or worsening peri-device leak in any of the patients. None of the patients had AF recurrence after the blanking period. CONCLUSION: LB PVI was safe and effective with 100% acute isolation of left-sided veins in patients with prior LAAO device.

Single-sweep pulmonary vein isolation using the new third-generation laser balloon-Evolution in ablation style using endoscopic ablation system.

BACKGROUND: The endoscopic ablation system (EAS) is an established ablation device for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). The novel X3 EAS is now equipped with a contiguous circumferential ablation mode (RAPID mode). AIM: To determine the feasibility of single-shot fashioned ablation using X3. METHODS: Consecutive patients who underwent AF ablation using X3 were enrolled. We assessed the acute procedural data focusing on "Single-sweep PVI" defined as successful PVI with a single RAPID mode energy application, and on "first-pass isolation" defined as successful PVI after initial circular lesion set. RESULTS: One hundred AF patients (56% male, age: 68 ± 10 years, 66% paroxysmal AF) were analyzed. A total of 379 of 383 PVs (99%) were isolated with X3. Single-sweep PVI and first-pass-isolation were achieved in 214 PVs (56%) and in 362 PVs (95%), respectively. Single-sweep PVI rates varied across PVs with higher rates at the superior PVs (61.2% vs. inferior PVs: 49.5%, p = .0239) and at PVs with maximal ostial diameter <24 mm (57.6% vs. >24 mm: 36.8%, p = .0151). The mean total procedure and fluoroscopy times were 43.0 ± 10 and 4.0 ± 2 min, respectively. In none of the patients an acute thromboembolic event (stroke or transient ischemic attack) or a pericardial effusion/tamponade occurred. A single transient phrenic nerve palsy was observed. CONCLUSION: The new X3 EAS allows for single-shot fashioned ablation in terms of single-sweep PVI in half or more of PVs. The new RAPID ablation mode leads to an improved rate of first-pass isolation associated with very short procedure times without compromising safety.

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies.

INTRODUCTION: Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF). METHODS AND RESULTS: Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre- and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/atrial wall thickness and the luminal area were measured at each segment. Twenty-seven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Post-ablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group. CONCLUSIONS: Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser balloon, RF shows markedly more thickening post-ablation with significant regional variations.

Second-generation laser balloon ablation for the treatment of atrial fibrillation assessed by continuous rhythm monitoring: the LIGHT-AF study.

AIMS: Balloon-based technologies have been developed to simplify catheter ablation of atrial fibrillation (AF), to improve the clinical outcome of the procedure and to achieve durable pulmonary vein isolation (PVI). The objective of this study is to evaluate the safety and efficacy of second-generation laser balloon (LB2) ablation in the treatment of AF using a continuous cardiac rhythm monitoring strategy. Atrial tachyarrhythmias (ATas) recurrences were assessed with implantable cardiac monitors (ICMs) or devices. METHODS AND RESULTS: All patients underwent LB2 ablation procedure. The primary endpoint was the first recurrence of any, >5.5 and >24 h duration ATas after the blanking period (90 days). In-hospital visits were performed at 3, 6, and 12 months. Seventy-three patients (68% male, mean age 59.8 ± 11.3) were included in the study. The average procedure, fluoroscopy, and laser ablation times were 81.5 ± 30.1, 21.5 ± 12.4, and 33.8 ± 9.7, respectively. All PVs were isolated using the LB2 with no need of touch-up using focal catheters. No major complications occurred during or after the procedures. The one-year freedom from recurrences was 66.9% (95% CI: 57.0-76.7%), 81.0% (69.5-88.5%), and 86.8% (76.1-92.9%) considering any, 5.5-h and 24-h cut-off duration, respectively. At 3, 6, and 12 months, any ATas was recorded in 22%, 32%, and 25% of patients, with a ≥5% arrhythmic burden documented in 4%, 5%, and 3%, respectively. Few patients reported AF-related symptoms (7%, 8%, and 5%). CONCLUSION: LB2 ablation is a safe and effective procedure, showing a high freedom from recurrences and low arrhythmic burden as documented by a continuous rhythm monitoring strategy.

Pulmonary vein narrowing after visually guided laser balloon ablation: Occurrence and clinical correlates.

INTRODUCTION: There are limited data focusing on pulmonary vein (PV) narrowing following ablation using a visually guided laser balloon (VGLB). We sought to assess the frequency and predictors of PV narrowing after VGLB ablation. METHODS AND RESULTS: Patients with paroxysmal atrial fibrillation treated with VGLB were screened. Study participants underwent contrast-enhanced computed tomography (CT) scanning before and 6 months after the procedure. We defined 25% to 49%, 50% to 74%, and 75% to 100% reduction in PV cross-sectional area as mild, moderate, and severe narrowing, respectively. Of 146 PVs in 38 patients analyzed, severe narrowing developed in two right superior and one right inferior PV. Moderate or severe narrowing occurred in 40 veins (27% of all PVs, 50% of the right superior, 22% of the right inferior, 21% of the left superior, and 14% of the left inferior PV). In PVs with moderate-severe narrowing, the baseline orifice area was significantly larger (4.1 [interquartile range, 3.2-4.8] vs 2.5 [1.9-3.3] cm2 , P < .0001), the narrowest region of stenosis was significantly more distal into the vessel (1.9 [0.7-2.9] vs 0 [0-1.7] mm from the orifice, P = .0006) and the total amount of energy delivered per vein was significantly greater (5190 ± 970 vs 4626 ± 1573 J, P = .018) than in PVs with mild or no significant narrowing. The baseline orifice area independently predicted moderate-severe narrowing in multivariate analysis (odds ratio, 1.8 [1.3-2.5] per 1 cm2 increase, P = .0003). No patient exhibited any signs or symptoms of PV stenosis. CONCLUSIONS: Baseline PV orifice area, ablating distally inside the veins, and total amount of laser energy are associated with PV narrowing after VGLB ablation.

Comparison between minimal fluoroscopy and conventional approaches for visually guided laser balloon pulmonary vein isolation ablation.

INTRODUCTION: Although balloon-based techniques, such as the laser balloon (LB) ablation have simplified pulmonary vein isolation (PVI), procedural fluoroscopy usage remains higher in comparison to radiofrequency PVI approaches due to limited 3-dimensional mapping system integration. METHODS: In this prospective study, 50 consecutive patients were randomly assigned in alternating fashion to a low fluoroscopy group (LFG; n = 25) or conventional fluoroscopy group (CFG; n = 25) and underwent de novo PVI procedures using visually guided LB technique. RESULTS: There was no statistical difference in baseline characteristics or cross-overs between treatment groups. Acute PVI was accomplished in all patients. Mean follow up was 318 ± 69 days. Clinical recurrence of atrial fibrillation after PVI was similar between groups (CFG: 19% vs LFG: 15%; P = .72). Total fluoroscopy time was significantly lower in the LFG than the CFG (1.7 ± 1.4  vs 16.9 ± 5.9 minutes; P < .001) despite similar total procedure duration (143 ± 22 vs 148 ± 22 minutes; P = .42) and mean LA dwell time (63 ± 15 vs 59 ± 10 minutes; P = .28). Mean dose area product was significantly lower in the LFG (181 ± 125 vs 1980 ± 750 µGym2 ; P < .001). Fluoroscopy usage after transseptal access was substantially lower in the LFG (0.63 ± 0.43 vs 11.70 ± 4.32 minutes; P < .001). Complications rates were similar between both groups (4% vs 2%; P = .57). CONCLUSIONS: This study demonstrates that LB PVI can be safely achieved using a novel low fluoroscopy protocol while also substantially reducing fluoroscopy usage and radiation exposure in comparison to conventional approaches for LB ablation.

Phrenic nerve injury in atrial fibrillation ablation using balloon catheters: Incidence, characteristics, and clinical recovery course.

AIMS: Systematic data on phrenic nerve palsy (PNP) associated with contemporary balloon ablation techniques (cryoballoon [CBA] vs laser balloon [LBA]) are sparse. We aimed to investigate the incidence, characteristics, and clinical recovery course in patients with PNP who underwent CBA or LBA. METHODS AND RESULTS: A total of 2433 consecutive patients who underwent balloon-based pulmonary vein isolation (CBA: n = 1720 and LBA: n = 713) were retrospectively identified. PNP was classified into (a) transient (recovery before discharge) or (b) persistent (within 6 months, 6-12 months, and >12 months) according to clinical recovery course. In general, PNP occurred significantly more often in CBA 71/1720 (4.2%) than LBA 11/713 (1.5%) (P = .003). The rate of transient PNP was significantly higher in CBA (3.0%, n = 45) than LBA (0.1%, n = 1, P = .004). The rate of persistent PNP did not significantly differ between two groups (CBA: 1.2% vs LBA: 1.4%, P = .89). The rate of persistent PNP which recovered within 6 months was similar (CBA: 17.4% vs LBA 18.2%, P = 1.000). However, the rates of persistent PNP which recovered within 6 to 12 months (CBA: 2.9% vs LBA 27.3%, P = .0171) and more than 12 months (CBA: 7.3% vs LBA 45.5%, P = .0034) were significantly higher in LBA. CONCLUSION: PNP occurred more often in CBA than LBA, however, the majority of PNP in CBA was transient whereas the majority of PNP in LBA was persistent. Either balloon technology is not superior in terms of long-term PNP.

Comparison of dragging ablation and point-by-point ablation with a laser balloon on linear lesion formation.

INTRODUCTION: Lesion size and continuity in dragging laser balloon (LB) ablation, which may enable fast and durable pulmonary vein isolation for atrial fibrillation, are unknown. We evaluated the differences in size and continuity of linear lesions formed by dragging ablation and conventional point-by-point ablation using an LB in vitro model. METHODS AND RESULTS: Chicken muscles were cauterized using the first-generation LB in dragging and point-by-point fashion. Dragging ablation was manually performed with different dragging speeds (0.5-2°/s) using an overlap ratio of the beginning and last site during one application at 12 W/20 s and 8.5 W/30 s. Point-by-point ablation was performed with 25% and 50% overlap ratios at six energy settings (5.5 W/30 s to 12 W/20 s). Lesion depth, width, and continuity were compared. Lesion continuity was assessed by the surface and deep visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each ablation protocol. Lesion depth and width in dragging ablation at high power (12 W) were comparable with most measurements in point-by-point ablation. Lesion depth and width were smaller at faster-dragging speed and lower power (8.5 W) in dragging ablation. The surface visible gap degree was better in dragging ablation at all dragging speeds than a 25% overlapped point-by-point ablation (p < .001). CONCLUSION: Dragging LB ablation at high power provides deep and continuous linear lesion formation comparable with that of point-by-point LB ablation. However, lesion depth and width depending on the dragging speed and power.

Influence of various energy settings and overlap ratios on size and continuity of lesions in a laser balloon ablation in vitro model.

INTRODUCTION: The influence of power (Watt [W]) and total energy (Joule [J]) on lesion size and the optimal overlap ratio remain unclear in laser balloon (LB) ablation for atrial fibrillation. We aimed to evaluate lesion size and visible gaps after LB ablation with various energy settings and different overlap ratios in vitro model. METHODS AND RESULTS: Chicken muscles were cauterized using the first-generation LB with single applications of full and a half duration of six energy settings (5.5 W/30 seconds [165 J] to 12 W/20 seconds [240 J]) and varying power (5.5-12 W) at the constant total energy (160 J). Three overlapped ablations with different ratios (25% and 50%) for each energy setting were also performed to evaluate the visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each energy setting. In single applications of full duration, lesion depth, lesion volume, and maximum lesion diameter increased according to the total energy (all, P < .001) and were greater than in those of half duration in each energy setting (all, P < .05). However, applications with larger power created larger lesion volume and maximum lesion diameter at constant total energy (P < .05). The visible gap degree was better in all energy settings with 50% overlapped ablation than in those with 25% (all, P < .001). CONCLUSION: Lesion size depends not only on power but also on total energy in the LB ablation. Sufficiently overlapped ablations allow continuous lesion formation.

Second-Generation Visually Guided Laser Balloon Ablation System for Pulmonary Vein Isolation: Learning Curve, Safety and Efficacy　- The MERLIN Registry.

BACKGROUND: Radiofrequency (RF)-based pulmonary vein isolation (PVI) results in a favorable clinical outcome, although its complexity demands a long learning curve. Balloon-based systems have been developed to possibly solve these limitations. The 2nd-generation laser balloon (LB2) offers optimized features for improved tissue contact and visibility. We determined the safety, efficacy and learning curve of the LB2 for PVI.Methods and Results:A total of 45 consecutive patients (89% persistent AF) were prospectively enrolled and divided into 3 groups (T1, T2, T3) of n=15 patients per group. All patients underwent PVI by 2 operators using the LB2. The operators were experienced in RF and cryothermal procedures, but not in laser ablations. A total of 174/177 PVs (98%) were successfully isolated. The median procedure time significantly declined from 132 (114, 158) to 119 (102, 127) and 91 (86, 105) min in T1-3, respectively (P=0.0009). Similarly, the median fluoroscopy time significantly decreased from T1 to T3 (22 (17, 27) vs. 21 (16, 24) vs. 13 (10, 17) min, respectively, P=0.045). Adverse events occurred in 6.7%, with a trend towards a lower complication rate with increasing experience. CONCLUSIONS: The LB2 was safe and effective for PVI, even for operators without any previous experience in laser balloon-based PVI. Procedure time, left atrial dwelling time and fluoroscopy time decreased after a learning curve of 15 cases.

Analysis of procedural data of pulmonary vein isolation for atrial fibrillation with the second-generation laser balloon.

BACKGROUND: The procedural data of pulmonary vein (PV) isolation (PVI) for patients with atrial fibrillation using the second-generation laser balloon (LB2), which became available recently, remains unclear and were evaluated. METHODS: Thirty consecutive patients (116 PVs) underwent PVI using LB2 (LB2 group) and were matched to 30 patients (116 PVs) treated with the first-generation laser balloon (LB1 group). The left atrial isolated surface area (ISA) (ratio of the total isolated antral surface area excluding PV to the total isolated antral surface area including the posterior wall) was also measured after LB2 PVI. RESULTS: PVI was achieved in 103/116 (89%) PVs and 108/116 (93%) PVs in the LB2 and LB1 groups, respectively, after the initial circular ablation (P = 0.360) and in 115/116 (99%) PVs and 116/116 (100%) PVs in the LB2 and LB1 groups, respectively, at the end of the procedure (P = 1.000). PV occlusion grade, categorized by the degree of PV occlusion, was significantly better in the LB2 group than in the LB1 group (P < 0.001). Zero rotational maneuver was applicable in 23/116 (20%) PVs and 8/116 (7%) in the LB2 and LB1 groups, respectively (P = 0.007). There was no significant difference in the procedural time, fluoroscopic time, or complications. The mean ISA after LB2 PVI was 53 ± 14%. The application number was the only independent predictor of successful PVI after initial circular LB2 ablation (adjusted odds ratio 0.860; 95% confidence interval 0.764-0.968; P = 0.013). CONCLUSION: LB2 displays favorable PV occlusion characteristics and enables more zero rotational maneuvers.

HEartLight guided - PUre Pulmonary Vein Isolation Regardless of Concomitant Atrial Substrate: HEURECA Study.

BACKGROUND: It remains unclear whether left atrial low-voltage area (LALVA) affects atrial tachyarrhythmia recurrence after laser balloon pulmonary vein isolation (PVI) for atrial fibrillation (AF). We prospectively evaluated the outcome of laser balloon PVI in patients with and without LALVA (≤ 0.5 mV) together with surface/intracardiac electrophysiological criteria. METHODS: One hundred consecutive paroxysmal/persistent AF patients underwent laser balloon PVI. The relative extent of LALVA (extent of LALVA/left atrial surface area × 100 [%]: rLALVA), total p-wave duration in lead II (PWD), and time interval from the beginning of p-wave to the local activation in left atrial appendage (TTLAA) were assessed. Patients were divided into patients with LALVA (group A: 23 patients) and those without LALVA (group B: 77 patients). The primary endpoint was freedom from atrial tachyarrhythmia after the blanking periods. RESULTS: Complete PVI was achieved in 99/100 (99%) patients. PWD and TTLAA were longer in group A (both, P < 0.001). During 12 months' follow-up, survival free from atrial tachyarrhythmia recurrence was lower in group A (12/23 [52%] patients vs 67/77 [87%] patients, P < 0.001). Multivariate analysis identified rLALVA as the only independent predictor of atrial tachyarrhythmia recurrence. rLALVA correlated with PWD and TTLAA (r = 0.41, P < 0.001 and r = 0.60, P < 0.001, respectively). Receiver operating characteristic curve for rLALVA revealed PWD of 122 ms and TTLAA of 92 ms as the optimal cut-off value. CONCLUSION: LALVA was associated with poorer outcome after laser balloon PVI. Patients may be identified by longer PWD and TTLAA.