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Background: The TactiFlex SE catheter (TFSE, Abbott) with a contact force (CF) sensor and a laser-cut irrigated-tip has recently become available but lacks a lesion quality marker. This study aimed to explore distinctions in lesion characteristics between the TFSE and the ThermoCool SmartTouch SurroundFlow catheter (STSF, Biosense Webster), which utilizes a porous irrigated tip, and to assess the most effective application settings for the TFSE. Methods: Lesions were generated using varying settings of radiofrequency power (30–50 W), CF (10–20 g), application duration (10–40 s), and catheter orientation (perpendicular or parallel) in an ex vivo porcine model. Comparative analysis between the TFSE and STSF was conducted for lesion characteristics and incidence of steam pops using predictive models in regression analyses. Results: Among 720 applications, the TFSE exhibited a significantly lower incidence of steam pops compared to the STSF (0.6% vs. 36.8%, P < 0.001). Moreover, coefficients of determination (R2) for the TFSE were higher than those for the STSF concerning lesion depth (0.710 vs. 0.541) and volume (0.723 vs. 0.618). The lesion size generated with the TFSE was notably smaller than that with the STSF under identical application settings. Additionally, to achieve a lesion depth ≥ 4.0 mm, the TFSE required an application duration 8–12 s longer than the STSF under similar settings. Conclusions: The TFSE demonstrated a lower incidence of steam pops and superior predictability in lesion size compared to the STSF. However, the TFSE necessitated a longer application duration than the STSF to achieve an adequate lesion size. [ABSTRACT FROM AUTHOR]

Background: The fibrosis-4 (FIB-4) index is a noninvasive scoring system that is used to assess the progression of liver fibrosis. This study aimed to assess whether the FIB-4 index is associated with recurrent atrial fibrillation (AF) after catheter ablation in patients with and without heart failure (HF). Methods: We included 1,184 patients who underwent initial AF catheter ablation between 2016 and 2021. The patients were classified into low-risk (< 1.3), intermediate-risk (1.3–2.67), and high-risk (> 2.67) groups based on their FIB-4 indices at baseline. The patients were divided into HF (n = 552) and non-HF groups (n = 632); the HF group was further divided into paroxysmal AF (PAF) and non-PAF groups. AF recurrence after catheter ablation was then compared among the groups. Results: In the non-HF group, no significant differences in recurrence after ablation were observed between the low-(n = 219), intermediate-(n = 364), and high-risk (n = 49) groups. In contrast, in the HF group, the intermediate-(n = 341) and high-risk (n = 112) groups had significantly higher recurrence rates than the low-risk group (n = 99) (log-rank test, p = 0.005). This association remained significant after multivariate analysis (hazard ratio [HR]:1.374; p = 0.027). The FIB-4 index increased incrementally as the brain natriuretic peptide levels and severity of tricuspid regurgitation increased. The FIB-4 index was an independent predictor of recurrence in the non-PAF HF group (HR:1.498; p = 0.007) but not in the PAF group. Conclusions: The FIB-4 index may be a useful predictor of AF recurrence after catheter ablation in patients with HF, particularly in those with non-PAF. [ABSTRACT FROM AUTHOR]

Background : Real-time phase mapping (ExTRa™) is useful in determining the strategy of catheter ablation for non-paroxysmal atrial fibrillation (AF). This study aimed to investigate the features of drivers of AF associated with its termination during ablation. Methods: Thirty-six patients who underwent catheter ablation for non-paroxysmal AF using online real-time phase mapping (ExTRa™) were enrolled. A significant AF driver was defined as an area with a non-passively activated ratio of ≥ 50% on mapping analysis in the left atrium (LA). All drivers were simultaneously evaluated using a low-voltage area, complex fractionated atrial electrogram (CFAE), and rotational activity by unipolar electrogram analysis. The electrical characteristics of drivers were compared between patients with and without AF termination during the procedure. Results: Twelve patients achieved AF termination during the procedure. The total number of drivers detected on the mapping was significantly lower (4.4 ± 1.6 vs. 7.4 ± 3.8, p = 0.007), and the drivers were more concentrated in limited LA regions (2.8 ± 0.9 vs. 3.9 ± 1.4, p = 0.009) in the termination group than in the non-termination group. The presence of drivers 2–6 with limited (≤ 3) LA regions showed a tenfold increase in the likelihood of AF termination, with 83% specificity and 67% sensitivity. Among 231 AF drivers, the drivers related to termination exhibited a greater overlap of CFAE (56.8 ± 34.1% vs. 39.5 ± 30.4%, p = 0.004) than the non-related drivers. The termination group showed a trend toward a lower recurrence rate after ablation (p = 0.163). Conclusions: Rotors responsible for AF maintenance may be characterized in cases with concentrated regions and fewer drivers on mapping. [ABSTRACT FROM AUTHOR]

Background: Isolation of the pulmonary veins (PVs) is the golden standard for atrial fibrillation (AF) ablation. To achieve a permanent PV isolation, the endoscopic guided HeartLight laser balloon system was invented. We analyzed the safety and efficacy of this laser balloon system. Methods and results: Three hundred four patients from 21 investigational sites inside Japan were enrolled in this study. One thousand sixty-two out of 1175 PVs (90.4%) were isolated using the HeartLight laser balloon. The isolation rate of the left superior, left inferior, right superior, and right inferior PVs was 87.8%, 91.3%, 91.6%, and 92.1%, respectively. The procedure time, defined as the time from the venous access to taking out the balloon, was 155 ± 39 min. The fluoroscopic time was 44 ± 25 min. The mean follow-up period was 309 ± 125 days. The freedom from AF recurrence at 3 months was 89.0% and at 12 months 82.1%. Adverse events occurred in 22 patients (7.2%) including phrenic nerve injury lasting more than 3 months in 1.6% and strokes in 1.0% of the patients. Conclusions: This initial experience demonstrated that the laser balloon ablation was feasible for PV isolation in Japanese AF patients. [ABSTRACT FROM AUTHOR]

Background: The distal hemisphere of a balloon is generally cooled during cryoapplication. However, a wide ablation area can be acquired after cryoballoon ablation. This study aimed to evaluate the extent of ice formation on two types of balloon surfaces through experimental and simulation studies. Methods: A standard cryoballoon (SCB; Arctic Front Advance Pro, Medtronic) and novel cryoballoon (NCB; POLARx, Boston Scientific) were frozen for 240 s in 36 °C normal saline solution to observe ice formation on the balloon surface. Pieces of porcine tissue were placed between the upper and lower sides of the balloon, and the balloon was frozen in the horizontal direction for 240 s in 20 attempts (10 for SCB and NCB each). The measured areas of ice formation were evaluated and compared between the upper and lower sides of each balloon. Results: Ice formation was greater on the lower side of the balloon than on the upper side. A larger area of ice formation in the tissue slab was observed on the lower side than on the upper side in both balloons, and the ice formation extended to the proximal hemisphere on the lower side of the balloon. The ice formation area in the NCB was significantly larger than that in SCB. Conclusions: Ice formation was significantly greater on the lower side of the cryoballoon than on the upper side and extended to the proximal hemisphere of the balloon, which might facilitate the acquisition of a wide ablation area on the left atrial posterior wall after cryoballoon ablation. Different ice formation after cryoballoon ablation Greater ice formation on the lower side of cryoballoon and an extensive ice formation in the proximal hemisphere, especially in novel cryoballoon. [ABSTRACT FROM AUTHOR]

Background and objectives: Mitral isthmus (MI) ablation for mitral flutter is technically difficult, and incomplete block line is not uncommon. The objective of this study is to investigate the effect of the ridge line of left pulmonary vein isolation (LPVI) from left atrial appendage (LAA) on completion rate of mitral isthmus (MI) block line and recurrence rate of atrial tachycardia (AT) or atrial flutter (AFL) after the first MI ablation. Methods: We identified 611 patients who underwent first MI ablation for mitral flutter during the study period. Finally, 559 patients were enrolled and divided into two groups according to the method of ridge line ablation of LPVI (LAA group, n = 467, conventional group, n = 92). Outcome measures were the completion of MI block line by first MI ablation, the recurrence of AT/AFL, and repeat MI ablation after the first MI ablation. Results: The first MI block line completion rate was significantly higher in the LAA group than the conventional group (95% vs. 85%, p < 0.001). The recurrence rate of AT/AFL after 3 months from first MI ablation was significantly lower in the LAA group. The requirement of additional MI ablation tended to be lower in the LAA group. Conclusions: Our novel approach of ablating LPV-LAA ridge from the LAA side during PVI can increase the success rate of MI block line completion, and reduce the recurrence rate of AT/AFL and the need for additional MI block line ablation. [ABSTRACT FROM AUTHOR]

Purpose: The effect of novel catheter ablation techniques for atrial fibrillation (AF) on the autonomic nervous system (ANS) is unclear. This study aimed to assess the ANS after three novel catheter ablation techniques for paroxysmal AF by evaluating heart rate variability (HRV) parameters using a 3-min electrocardiogram recording.Methods: Two hundred and thirty-five patients who underwent catheter ablation for paroxysmal AF (119 in irrigated-tip, 51 in contact-force sensing-guided, and 65 patients in second-generation cryoballoon ablation) were included. HRV analysis was performed at baseline and 1, 3, 6, and 12 months after the ablation.Results: The three ablation groups had similarly decreased HRV parameters after the ablation, and this change was maintained > 1 year. A reduction in parasympathetic nervous function was more apparent after the ablation, compared to changes in the sympathetic nervous function. Of the total population, 45 patients had recurrence. Ln high frequency (HF) 12 months after the ablation was significantly higher in the recurrence group than in the non-recurrence group (1.52 ± 0.47 vs. 1.26 ± 0.57 ms2, p = 0.007). Multivariate analysis demonstrated that AF duration (hazards ratio 1.09, 95% confidence interval 1.04-1.15, p = 0.001) and ln HF 12 months after ablation (hazards ratio 1.91, 95% confidence interval 1.12-3.25, p = 0.017) were independent predictors of AF recurrence after the ablation.Conclusions: ANS modulation after the three catheter ablation methods was similar and maintained > 1 year after the procedure. Higher parasympathetic nervous function at 1 year after ablation was associated with AF recurrence after the ablation. [ABSTRACT FROM AUTHOR]

A 58-year-old woman underwent laser balloon ablation for atrial fibrillation. Standard laser ablation was performed encircling the left superior pulmonary vein (LSPV); however, electrical isolation of the LSPV was not achieved after repetitive ablations. During carina ablation of the LSPV and LIPV, laser power was titrated to 8.5 W × 20 s and 10 W × 20 s, respectively. b Intra-cardiac electrogram showing disappearance of LSPV potentials during LIPV ablation. c Fluoroscopic image during LIPV ablation. [Extracted from the article]