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Introduction: Catheter ablation of ectopy originating from the vicinity of the His bundle can be challenging. Methods and Results: We report a case of a 33‐year‐old man with narrow QRS ectopy with preferential conduction from a para‐Hisian origin to the proximal left fascicles, which was successfully eliminated by radiofrequency ablation in the right coronary cusp, guided by ultrahigh‐resolution mapping of the His bundle, bundle branch, and fascicular electrograms. Conclusion: Some narrow QRS ectopy may originate from the vicinity of the conduction system, instead of the "true" conduction system, and have concealed connections from its origin to the conduction system. [ABSTRACT FROM AUTHOR]

Introduction: Proactive esophageal cooling has been FDA cleared to reduce the likelihood of ablation‐related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures. Data suggest that procedure times for RF pulmonary vein isolation (PVI) also decrease when proactive esophageal cooling is employed instead of luminal esophageal temperature (LET) monitoring. Reduced procedure times may allow increased electrophysiology (EP) lab throughput. We aimed to quantify the change in EP lab throughput of PVI cases after the introduction of proactive esophageal cooling. Methods: EP lab throughput data were obtained from three EP groups. We then compared EP lab throughput over equal time frames at each site before (pre‐adoption) and after (post‐adoption) the adoption of proactive esophageal cooling. Results: Over the time frame of the study, a total of 2498 PVIs were performed over a combined 74 months, with cooling adopted in September 2021, November 2021, and March 2022 at each respective site. In the pre‐adoption time frame, 1026 PVIs were performed using a combination of LET monitoring with the addition of esophageal deviation when deemed necessary by the operator. In the post‐adoption time frame, 1472 PVIs were performed using exclusively proactive esophageal cooling, representing a mean 43% increase in throughput (p <.0001), despite the loss of two operators during the post‐adoption time frame. Conclusion: Adoption of proactive esophageal cooling during PVI ablation procedures is associated with a significant increase in EP lab throughput, even after a reduction in total number of operating physicians in the post‐adoption group. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high‐power short duration (vHPSD—90W/4 s) PVI using the Q‐Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long‐term effectiveness is lacking. We analyzed lesion metrics and 12‐month freedom from atrial arrythmia with this approach. Methods: Our approach to radiofrequency (RF) PVI under MCS is standardized and includes a single catheter approach with a steerable sheath. We identified patients undergoing Q‐Dot RF PVI between March 2021 and December 2022 in our center, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50 W ablation under GA (50 W/GA) up to 12 months of follow‐up. Data were extracted from clinical records and the CARTO system. Results: Eighty‐three patients met our inclusion criteria (51 90W/MCS; 32 50 W/GA). Despite shorter ablation times (353 vs. 886 s; p <.001), the 90 W/MCS group received more lesions (median 87 vs. 58, p <.001), resulting in similar procedure times (149.3 vs. 149.1 min; p =.981). PVI was achieved in all cases, and first pass isolation rates were similar (left wide antral circumferential ablation [WACA] 82.4% vs. 87.5%, p =.758; right WACA 74.5% vs. 78.1%, p =.796; 90 W/MCS vs. 50 W/GA respectively). Analysis of 6647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs. 10.0 ± 2.2 Ω; p =.989) and mean contact force (14.6 ± 2.0 g vs. 15.1 ± 1.6 g; p =.248). Only median 2.5% of lesions in the 90 W/MCS cohort failed to achieve ≥ 5 Ω drop. In the 90 W/MCS group, there were no procedural related complications, and 12‐month freedom from atrial arrhythmia was observed in 78.4%. Conclusion: vHPSD PVI is feasible under MCS, with encouraging acute and long‐term procedural outcomes. This provides a compelling option for centers with limited anaesthetic support. [ABSTRACT FROM AUTHOR]

Introduction: Through systematic scientific rigor, the CLOSE guided workflow was developed and has been shown to improve pulmonary vein isolation durability. However, this technique was developed at a time when using power‐controlled ablation catheters with conventional power ranges was the norm. There has been increased adoption of a high‐power and very high‐power short‐duration ablation practice propelled by the availability of the temperature‐controlled radiofrequency QDOT MICRO catheter. Methods: There are fundamental differences in biophysics between very high‐ powered temperature guided ablation and conventional ablation strategy that may impact patient outcomes. The catheter's design and ablation modes offer flexibility in technique while accommodating the individual operator's clinical discretion and preference to deliver a durable, transmural, and contiguous lesion set. Results: Here, we provide recommendations for 3 different workflows using the QDOT MICRO catheter in a step‐by‐step manner for pulmonary vein isolation based on our cumulative experience as early adopters of the technology and the data available in the scientific literature. Conclusions: With standardization, temperature‐controlled ablation with the QDOT MICRO catheter provides operators the flexibility of implementing different ablation strategies to ensure durable contiguous pulmonary vein isolation depending on patient characteristics. [ABSTRACT FROM AUTHOR]

Introduction: Lesion size index (LSI) was introduced with the use of Tacticath™ and as a surrogate of lesion quality. The metric used to achieve the predetermined values involves combined information of contact force (CF), power and radiofrequency time. Rapid atrial pacing (RAP) and high‐frequency low‐tidal volume ventilation (HFLTV) independently or in combination improve catheter stability and CF and quality of lesions. Data of the impact of body weight adjusted HFLTV ventilation strategy associated with RAP in the lesion metrics still lacking. The study aimed to compare the results of high‐power short‐duration (HPSD) atrial fibrillation ablation using simultaneous weight adjusted HFLTV and RAP and standard ventilation (SV) protocol. Methods: Prospective, nonrandomized study with 136 patients undergoing de novo ablation divided into two groups; 70 in RAP (100 ppm) + HFLTV with 4 mL/kg of tidal volume and 25 breaths/min (group A) and 66 patients with SV in intrinsic sinus rhythm (group B). Ablation using 50 W, CF of 5–10 g/10–20 g and 40 mL/minute flow rate on the posterior and anterior left atrial wall, respectively. Results: No procedure‐related complications. Group A: Mean LSI points 70 ± 16.5, mean total lower LSI 3.4 ± 0.5, mean total higher LSI 8.2 ± 0.4 and mean total LSI 5.6 ± 0.6. Anterior and posterior wall mean total LSI was 6.0 ± 0.4 and 4.2 ± 0.3, respectively. Mean local impedance drop (LID) points were 118.8 ± 28.4, mean LID index (%) 12.9 ± 1.5, and mean LID < 12% points 55.9 ± 23.8. Anterior and posterior wall mean total LID index were 13.6 ± 2.0 and 11.9 ± 1.7, respectively. Recurrence in 11 (15.7%) patients. Group B: Mean LSI points 56 ± 2.7, mean total lower LSI 2.9 ± 0.7, mean total higher LSI 6.9 ± 0.9, and mean total LSI 4.8 ± 0.8. Anterior and posterior wall mean total LSI was 5.1 ± 0.3 and 3.5 ± 0.5, respectively. Mean LID points were 111.4 ± 21.5, mean LID index (%) 11.4 ± 1.2, and mean LID < 12% points 54.9 ± 25.2. Anterior and posterior wall mean total LID index were 11.8 ± 1.9 and 10.3 ± 1.7, respectively. Recurrence in 14 (21.2%) patients. Mean follow up was 15.2 ± 4.4 months. Conclusion: Weight adjusted HFLTV ventilation with RAP HPSD ablation produced lower recurrence rate and better LSI and LID parameters in comparison to SV and intrinsic sinus rhythm. [ABSTRACT FROM AUTHOR]

Introduction: Cather ablation (CA) is a well‐recognized treatment alternative for atrial fibrillation (AF) patients despite more than 20% ablation‐treated patients suffering from AF recurrence. The underlying mechanism of AF recurrence postablation is probably associated with high cardiac parasympathetic activity, which can be assessed with deceleration capacity (DC) of heart rate. Given that the relationship between DC and AF recurrence is still controversial, this systematic review and meta‐analysis was performed to investigate the characteristics of DC in patients with and without AF recurrence, evaluating the prognostic value of DC in AF patients after CA. Methods: A literature search was systematically performed in the Embase, PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases until October 01, 2023. The observational studies reporting either the pre‐ and postablation DC in both recurrence and non‐recurrence groups or the ratios based on DC for predicting AF recurrence were mainly included. Weighted mean differences (WMD) or odds ratios (OR) based on DC would be calculated with a random‐effect model, if heterogeneity estimated with the I 2 index and Q statistic was significant (I² > 50% or p < .05); otherwise, a fixed‐ effect model would be utilized. Results: A total of eight observational studies involving 914 AF patients treated with radiofrequency or cryoballoon ablation were included in this study. Ablation‐treated patients with AF recurrence had the higher DC postablation in relation to those without recurrence (WMD, 1.00; 95% confidence interval [CI], 0.33–1.67; p < .01), which was present up to 3 months of follow‐up (WMD, 1.54; 95% CI, 1.11–1.96; p < .01), whereas there was no statistical significance in DC before ablation between recurrence and non‐recurrence groups (WMD, 0.34; 95% CI, −0.12 to 0.79; p = .15). The high DC postablation was a risk factor for AF recurrence in ablation‐treated patients (OR, 2.17; 95% CI, 1.44–3.25; p < .01). Conclusion: The high DC postablation was associated with the risk of AF recurrence, suggesting that DC may act as a prognostic indicator in AF patients treated with CA. [ABSTRACT FROM AUTHOR]

Introduction: When ventricular tachycardia (VT) recurs after standard RF ablation (sRFA) some patients benefit from repeat sRFA, whereas others warrant advanced methods such as intramural needle ablation (INA). Our objectives are to assess the utility of repeat sRFA and to clarify the benefit of INA when repeat sRFA fails in patients with VT due to structural heart disease. Methods: In consecutive patients who were prospectively enrolled in a study for INA for recurrent sustained monomorphic VT despite sRFA, repeat sRFA was considered first. INA was performed during the same procedure if repeat sRFA failed or no targets for sRFA were identified. Results: Of 85 patients enrolled, acute success with repeat sRFA was achieved in 30 patients (35%), and during the 6‐month follow‐up, 87% (20/23) were free of VT hospitalization, 78% were free of any VT, and 7 were lost to follow‐up. INA was performed in 55 patients (65%) after sRFA failed, or no endocardial targets were found abolished or modified inducible VT in 35/55 patients (64%). During follow‐up, 72% (39/54) were free of VT hospitalization, 41% were free of any VT, and 1 was lost to follow‐up. Overall, 59 out of 77 (77%) patients were free of hospitalization and 52% were free of any VT. Septal‐origin VTs were more likely to need INA, whereas RV and papillary muscle VTs were less likely to require INA. Conclusions: Repeat sRFA was beneficial in 23% (18/77) of patients with recurrent sustained VT who were referred for INA. The availability of INA increased favorable outcomes to 52%. [ABSTRACT FROM AUTHOR]

Introduction: Luminal esophageal temperature (LET) monitoring during atrial fibrillation (AF) ablation is widely used to reduce the incidence of endoscopically detected esophageal lesion (EDEL). We sought to assess whether specific patterns of LET variation are associated with EDEL. Methods: A high‐fidelity multisensor probe was used to record LET in AF patients undergoing radiofrequency ablation (RFA) or cryoballoon ablation (CBA). Explainable machine learning and SHapley Additive exPlanations (SHAP) analysis were used to predict EDEL and assess feature importance. Results: A total of 94 patients (38.3% persistent AF, 71.3% male, 72 RFA, and 22 CBA) were included. EDEL was detected in 11 patients (10 RFA and one CBA). In the RFA group, the highest LET recorded was similar between patients with and without EDEL (40.6 [40.1–41]°C vs. 40.2 [39.1–40.9]°C; p =.313), however, the rate of LET rise for the highest recorded peak was higher (0.08 [0.03–0.12]°C/s vs. 0.02 [0.01–0.05]°C/s; p =.033), and the area under the curve (AUC) for the highest peak was smaller (412.5 [206.8–634.1] vs. 588.6 [380.4–861.1]; p =.047) in patients who had EDEL. In case of CBA, the patient with EDEL had a faster LET decline (0.12 vs. 0.07 [0.02–0.14]°C/s), and a smaller AUC for the lowest trough (2491.3 vs. 2629.3 [1712.6–5283.2]). SHAP analysis revealed that a rate of LET change higher than 0.05°C/s and an AUC less than 600 were more predictive of EDEL in RFA. Conclusion: The rate of LET change and AUC for the recorded temperature predicted EDEL, whereas absolute peak temperatures did not. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 54-year-old man undergoing radiofrequency ablation for atrial fibrillation, encountering an irregular tachycardia during the procedure. Topics discussed include the mechanism of irregular tachycardia, interpretation challenges due to its irregularity, and the diagnosis of orthodromic reciprocating tachycardia.

Introduction: With the entry of pulsed‐field ablation (PFA) into electrophysiology, new possibilities for ablation of different substrates such as epicardial foci of premature ventricular contractions (PVCs) from coronary venous system (CVS) have been opened. Methods: This article focuses on a case of a 27‐year‐old patient with frequent monomorphic PVCs of epicardial origin, treated by radiofrequency ablation, followed by PFA. Results: After unsuccessful focus ablation through CVS with RFA, successful ablations from the same region with PFA were achieved. Conclusion: This is the first described case of successful ablation of epicardial PVCs using PFA, which we hope will help in defining indications for this novel technology and enhance quality of treatment for patients with different arrhythmias. [ABSTRACT FROM AUTHOR]

Introduction: Despite rapid technological progress, some arrhythmias are still resistant to standard unipolar ablation. These include arrhythmias arising from the base of the heart, cardiac crux, or epicardium. Bipolar radiofrequency ablation (B‐RFA) may be useful in some cases, however, data on the efficacy of this approach in various arrhythmia localizations are scarce. The aim of this study was to assess the efficacy of B‐RFA in patients with ventricular arrhythmias originating from various locations, occurring refractory to standard unipolar ablation approaches. Methods: An observational, single center study was conducted over a 30‐month period. B‐RFA were performed using dedicated radio frequency (RF) generator and electroanatomic mapping system. Results: Twenty‐four procedures, in 23 patients with a median (range) of 1 (1–2) previously failed unipolar ablation procedures, were included in the final analysis. There were 12 ablations of ventricular arrhythmias originating from interventricular septum with an acute success rate of 75%, and 12 from left ventricular (LV) summit with an acute success rate of 58%. The midterm success rate (median interquartile range follow‐up of 205 days [188–338]) was 66% and 50%, respectively. Conclusions: B‐RFA is a promising method of catheter ablation for refractory cardiac arrhythmias. A higher success rate was observed in ablation for difficult ventricular arrhythmias originating from interventricular septal region than LV summit. [ABSTRACT FROM AUTHOR]

Introduction: Some previous studies have reported that a first‐step ethanol infusion into the vein of Marshall (EIVOM) with touch‐up radiofrequency (RF) ablation can facilitate mitral isthmus (MI) block and improves the ablation outcomes in persistent atrial fibrillation (PeAF) patients. However, the effect of an initial RF ablation with an adjunctive EIVOM has not been fully investigated. Methods: This study enrolled 233 PeAF patients undergoing pulmonary vein isolation and linear ablation including an MI, roof line, and cavotricuspid isthmus ablation. An EIVOM was performed when endocardial ablation with or without coronary sinus ablation failed to create MI block. Results: Bidirectional MI block was achieved in 224 patients (96.1%). Among them, MI block was obtained by only RF ablation in 174/224 patients (77.7%) (RF group) and an adjunctive EIVOM was needed in 50/224 (22.3%) (EIVOM group). During the follow‐up, 113 (64.9%) RF group patients were free from AF/atrial tachycardia compared to 41 (82.0%) EIVOM group patients (log‐rank p =.045). In a multivariate Cox regression analysis, an adjunctive EIVOM was associated with a lower recurrence rate (hazard ratio = 0.39, 95% confidence interval = 0.17–0.78, p =.006). Conclusion: An initial RF ablation with an adjunctive EIVOM strategy improved MI ablation's acute success rate and was associated with better clinical outcomes. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the progression of electrophysiological phenomena in atrial fibrillation (AF) and elucidate the association between the left atrial conduction velocity (LACV) and AF recurrence after pulmonary vein isolation. Methods: A total of 188 AF patients (121 paroxysmal AF and 67 persistent AF) who underwent PVI for the first time were enrolled in this prospective study. The left atrium was mapped using a 20‐pole electrode catheter combined with the CARTO3 system. The conduction distances and conduction times of the left atrium from the Bachmann bundle area to the mitral isthmus were calculated. Anterior, posterior, and septal LACV were calculated as conduction distance divided by conduction time. Results: The anterior, posterior, and septal LACVs in the AF recurrence group were slower than those in the nonrecurrence group (anterior: 0.807 [0.766, 0.848] and 1.048 [1.000, 1.093] m/s, p <.05; posterior: 1.037 [0.991, 1.084] vs. 1.315 [1.249, 1.380] m/s, p <.05; septal: 0.904 [0.862, 0.946] vs. 1.163 [1.107, 1.219] m/s, p <.05). The best cut‐off value of anterior LACV for predicting AF recurrence was 0.887 m/s (sensitivity 73.9% and specificity 76.5%). Multivariate analysis showed slow anterior LACV <0.887 m/s was an independent predictor of AF recurrence with an adjusted odds ratio of 1.42 (1.04, 1.94). Conclusions: Slowing conduction velocity is a predictor of AF recurrence after pulmonary vein isolation. [ABSTRACT FROM AUTHOR]

Introduction: Atrial fibrillation and atrial flutter originating from the donor s heart is a commonly reported complication post heart transplant. Atrial tachyarrhythmia originating from the recipient s heart, propagated through recipient‐to‐donor connections, is rare with only few cases reported in the literature; most reported cases from our review occur years post‐transplant. Case: A 47‐year‐old male presented with atrial tachycardia 6 months post heart transplant. Electrophysiologic study demonstrated atrial fibrillation originating from native heart and propagated through atrio‐atrial connections to the donor heart. This arrhythmia was successfully terminated with radiofrequency ablation. Conclusion: Atrio‐atrial connection between recipient and donor can form as early as a few months post heart transplant. Radiofrequency ablation appears to be an effective treatment for atrial fibrillation propagated through donor‐to‐recipient connections. [ABSTRACT FROM AUTHOR]

Introduction: Dual atrioventricular nodal non‐reentrant tachycardia (DAVNNT) is a rare and challenging‐to‐diagnose arrhythmia, without previous reports associating it with a leftward inferior extension (LIE). Methods: Diagnosis was made using adenosine triphosphate (ATP) injection during atrial pacing in a suspected DAVNNT patient. Results: Ablation of the rightward inferior extension was unsuccessful in eliminating DAVNNT; however, subsequent ablation of the LIE successfully eradicated the arrhythmia. Conclusion: This unique case, marked by the first instance of DAVNNT caused by LIE, diagnosed through ATP injection, underscores the utility of this diagnostic approach and broadens the spectrum of our understanding and management of this condition. [ABSTRACT FROM AUTHOR]

Introduction: It would be helpful in determining ablation strategy if the occurrence of perimitral atrial tachycardia (PMAT) could be predicted in advance. We investigated whether estimated perimitral conduction time (E‐PMCT), namely, twice the time between coronary sinus (CS) pacing and the ensuing wave‐front collision at the opposite side of the mitral annulus, correlated with the cycle length of PMAT and could predict future PMAT. Methods and Results: We retrospectively (retrospective cohort) and prospectively (validation cohort) investigated atrial fibrillation patients who had received pulmonary vein isolation (PVI) and in whom left atrial maps had been created during CS pacing. We calculated their E‐PMCT. PMAT was observed either by provocation or during follow‐up in 25, AT other than PMAT was observed in 24 (non‐PMAT AT group), and 53 patients never displayed any AT (no‐AT group) in the retrospective cohort. In the PMAT group of the retrospective cohort, a strong positive correlation was observed between the PMAT CL and E‐PMCT (r =.85, p < 0.001). PMAT was never induced nor observed in patients with E‐PMCT less than 176 ms, and the best cut‐off value for PMAT was 180 ms by receiver‐operating characteristic curve analysis. In the validation cohort of 76 patients, the cut‐off value of the E‐PMAT less than 180 ms predicted noninducibility of PMAT, with a sensitivity of 78.6%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 25.0%. Conclusion: Short E‐PMCT may predict noninducibility of PMAT and guide a less invasive ablation strategy. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is an established treatment strategy for atrial fibrillation (AF). To improve PVI efficacy and safety, high‐power short‐duration (HPSD) ablation and pulsed‐field ablation (PFA) were recently introduced into clinical practice. This study aimed to determine the extent of myocardial injury and systemic inflammation following PFA, HPSD, and standard RFA using established biomarkers. Methods: We included 179 patients with paroxysmal AF receiving first‐time PVI with different ablation technologies: standard RFA (30–40 W/20–30 s, n = 52), power‐controlled HPSD (70 W/5–7 s, n = 60), temperature‐controlled HPSD (90 W/4 s, n = 32), and PFA (biphasic, bipolar waveform, n = 35). High‐sensitivity cardiac troponin T (hs‐cTnT), creatine kinase (CK), CK MB isoform (CK‐MB), and white blood cell (WBC) count were determined before and after ablation. Results: Baseline characteristics were well‐balanced between groups (age 63.1 ± 10.3 years, 61.5% male). Postablation hs‐cTnT release was significantly higher with PFA (1469.3 ± 495.0 ng/L), HPSD‐70W (1322.3 ± 510.6 ng/L), and HPSD‐90W (1441.2 ± 409.9 ng/L) than with standard RFA (1045.9 ± 369.7 ng/L; p <.001). CK and CK‐MB release was increased with PFA by 3.4‐fold and 5.8‐fold, respectively, as compared to standard RFA (p <.001). PFA was associated with the lowest elevation in WBC (Δ1.5 ± 1.5 × 109/L), as compared to standard RFA (Δ3.8 ± 2.5 × 109/L, p <.001), HPSD‐70W (Δ2.7 ± 1.7 × 109/L, p =.037), and HPSD‐90W (Δ3.6 ± 2.5 × 109/L, p <.001). Conclusion: Among the four investigated ablation technologies, PFA was associated with the highest myocardial injury and the lowest inflammatory reaction. [ABSTRACT FROM AUTHOR]

Introduction: In patients with prior atrial septal defect (ASD) closure and atrial tachyarrhythmias, transseptal puncture can be challenging. Methods and Results: This case report discusses a 65‐year‐old man who had previously undergone pulmonary vein isolation (PVI) and cavo‐tricuspid isthmus ablation for atrial fibrillation before ASD closure, respectively. He developed atrial tachycardia (AT) and underwent catheter ablation. AT was diagnosed as peri‐mitral flutter and the mitral isthmus (MI) linear ablation via a trans‐aortic approach successfully terminated it. Conclusion: This case demonstrates the feasibility and safety of transaortic MI linear ablation in patients with ASD closure devices or anatomical challenges when transseptal puncture is difficult. [ABSTRACT FROM AUTHOR]

Background: Despite the potential benefits of ethanol infusion into the vein of Marshall (EIVOM) for atrial fibrillation (AF) ablation, concerns about its reversible and unpredictable effects persist. Objective: To assess the effectiveness of EIVOM in the vein of Marshall (VOM) with collateral veins (CVs) during mitral isthmus and AF ablation. Methods: We included 142 AF patients. EIVOM was performed before radiofrequency ablation, and low‐voltage areas (<0.5 mV) were measured before, immediately after, and 1 h after EIVOM. Results: Among the 142 patients, 93 (65%) underwent EIVOM, and among these, 35 (37%) were found to have CVs. In the VOM with CVs group, areas with low voltage measured 0 (0–1.85) cm2 before EIVOM, 6.9 (4.1–11.2) cm2 immediately after EIVOM, and 5.7 (3.5–10.6) cm2 1 h after EIVOM. Conversely, in the group designated as VOM without CVs—from which the nine leakage cases were excluded—the areas measured 0 (0–1.35) cm2, 5.5 (2.6–11.8) cm2, and 4.7 (1.8–13.5) cm2 at the respective time points. MI line block was fully achieved in 89% (31/35) of cases in the VOM with CVs group and 88% (44/49) in the VOM without CVs groups (p =.94). There was no significant difference in the outcome of AF ablation between these groups (log‐rank p =.73). Additionally, no significant difference was observed between EIVOM (+) and EIVOM (−) groups (log‐rank p =.59). Conclusion: EIVOM effectively creates MI line block, and its beneficial effects are sustained for at least 1 h after the procedure despite the low‐voltage areas showing a slight reduction in size. [ABSTRACT FROM AUTHOR]

Introduction: Mechanical force to achieve transseptal puncture (TSP) using a standard needle may lead to overshooting and injury, and can potentially be avoided using a radiofrequency (RF)‐powered needle or wire. Applying electrocautery to needles and guidewires as an alternative to purpose‐built RF systems has been associated with safety risks, such as tissue coring and thermal damage. The commercially available AcQCross needle‐dilator system (Medtronic) features a sharp open‐ended needle for mechanical puncture, as well as a built‐in connector to enable energy delivery for RF puncture. This investigation compares the safety and efficacy of the AcQCross needle to the dedicated VersaCross RF wire system and generator (Baylis Medical/Boston Scientific). Methods: In an ex vivo porcine model, VersaCross wire punctures were performed using 1 s, constant mode (approx. 10 W) with maximum two attempts. AcQCross punctures were performed by applying energy for 2 s using a standard electrosurgical generator at 10 W (max. five attempts), 20 W (max. two attempts), and 30 W (max. two attempts). Efficacy was assessed in terms of puncture success and a number of energy applications required for TSP. Safety was assessed quantitatively as force required for TSP, energy required to puncture, and incidence of tissue coring, as well as by qualitative assessment of puncture sites. Additional qualitative observation of tissue cores and debris were obtained from TSP performed in live swine. Results: RF TSP was 100% successful using the VersaCross wire with 1.0 ± 0.0 attempts. When power was used with the AcQCross needle, it failed to puncture at low (10 and 20 W) power settings; TSP was achieved with 30 W of energy with 91% success using 1.53 ± 0.51 attempts (p <.05 vs. VC) with greater variability (F1,33 = 9223.5, p <.0001). Compared to RF puncture using the VersaCross system, mechanical puncture, alone, using the AcQcross needle required six times more force (8 mm additional forward device displacement) to perforate the septum. Qualitative assessment of puncture sites revealed larger defects and more tissue charring with the AcQCross needle at 30 W compared to punctures with VersaCross wire. Tissue coring with the open‐ended AcQCross needle was observed in vivo and measured to occur in 57% of punctures using the ex vivo model; no coring was observed with the closed‐tip VersaCross wire. Conclusions: The AcQCross needle frequently required higher energy of 30 W to achieve RF TSP and was associated with tissue coring and charring, which have been, previously, reported when electrifying a standard open‐ended mechanical needle or guidewire. These findings may limit safety and effectiveness compared to the VersaCross system. [ABSTRACT FROM AUTHOR]

Radiofrequency (RF) ablation of intramural ventricular arrhythmias (VAs) may require advanced ablation techniques to achieve effective energy transfer to the targeted tissue. As an alternative to standard RF ablation, catheter ablation can also be conducted in bipolar configuration when two ablation catheters participate in the RF circuit. This strategy has proved to result in deeper lesion formation and may be effective for eliminating arrhythmias that have been refractory to standard ablation. In this article, we provide a step‐by‐step guide on when and how to perform bipolar ablation of VAs. [ABSTRACT FROM AUTHOR]

Introduction: Catheter ablation of atrial fibrillation (AF) has emerged as the most effective therapy. However, rare anatomical abnormalities such as situs inversus totalis, dextrocardia, or interrupted inferior vena cava can make ablation challenging. Methods and Results: We report a case of a 55‐year‐old woman with situs inversus totalis, dextrocardia, surgical atrial septal defect repair, left‐sided dual chamber pacemaker in place, and symptomatic recurrent persistent AF who underwent successful pulmonary vein and posterior wall isolation by the superior access from the left internal jugular vein. Conclusions: It is a feasible and safe approach with support of transesophageal echocardiography and multiple emerging technologies. [ABSTRACT FROM AUTHOR]

Background and Aims: Ablation of anteroseptal accessory pathways (AS‐AP) is challenging, with lower success and more complications compared to other APs. AS‐APs can be successfully ablated from the right atrium (RA) or the aortic valve's noncoronary cusp (NCC). We report two patients who required a hybrid ablation approach to achieve successful abolition of both anterograde and retrograde AS‐AP conduction. Methods and Results: A 21‐year‐old female with supraventricular tachycardia (SVT) and pre‐excitation on electrocardiogram (ECG) underwent electrophysiology study (EPS) confirming an AS‐AP with anterograde and retrograde conduction. Ablation in the NCC achieved immediate and persistent anterograde conduction block. Electrophysiological maneuvers showed persistent retrograde AP conduction and orthodromic reciprocating tachycardia (ORT) remained easily inducible. Additional ablation in the NCC did not eliminate retrograde conduction. Further ablation in the RA opposite the NCC at the site of earliest retrograde atrial activation during ORT restored sinus and eliminated retrograde AP conduction. A 52‐year‐old male with SVT and ECG with pre‐excitation underwent EPS that confirmed an AS‐AP with anterograde and retrograde conduction. Ablation was performed in the NCC resulting in immediate elimination of pre‐excitation. Retrograde conduction was still present and confirmed by repeating electrophysiological maneuvers. Ablation was performed in the RA opposite the successful ablation site in the NCC, eliminating retrograde AP conduction. Conclusion: Two cases of AS‐AP with anterograde and retrograde conduction and successful elimination of pathway conduction required a hybrid ablation approach from the NCC and RA. This approach may be helpful in other cases to improve success rates without using excessive ablation near the normal conduction system. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary vein isolation (PVI) is a pivotal part of ablative therapy for atrial fibrillation (AF). Currently, there are multiple techniques available to realize PVI, including: manual‐guided cryoballoon (MAN‐CB), manual‐guided radiofrequency (MAN‐RF), and robotic magnetic navigation‐guided radiofrequency ablation (RMN‐RF). There is a lack of large prospective trials comparing contemporary RMN‐RF with the more conventional ablation techniques. This study prospectively compared three catheter ablation techniques as treatment of paroxysmal AF. Methods: This multicenter, prospective study included patients with paroxysmal AF who underwent their first ablation procedure. Procedural parameters (including procedural efficiency), complication rates, and freedom of AF during 12‐month follow‐up, were compared between three study groups which were defined by the utilized ablation technique. Results: A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN‐CB (78 ± 21 min) compared to MAN‐RF (115 ± 41 min; p <.001) and compared to RMN‐RF (129 ± 32 min; p <.001), whereas it was comparable between the two radiofrequency (RF) groups (p =.062). A 3% complication rate was observed, which was comparable between all groups. At 12‐month follow‐up, AF recurrence was observed in 40 patients (19%) and was significantly lower in the robotic group (MAN‐CB 19 [24%], MAN‐RF 16 [23%], RMN‐RF 5 [8%] AF recurrences, p =.045) (multivariate hazard ratio of RMN‐RF on AF recurrence 0.32, 95% confidence interval: 0.12–0.87, p =.026). Conclusion: RMN‐guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time‐efficient ablation technique, whereas RMN nowadays has comparable efficiency with manual RF ablation. [ABSTRACT FROM AUTHOR]

Background: A novel ablation technique with guidewire has emerged as a promising approach for mapping and ablation of arrhythmias originating from left ventricular summit. However, its biophysical characteristics have not been fully clarified. Methods and Results: In the in vitro experiment, guidewire ablation (GA) was performed in vessel models of 1.17 and 2.24 mm to determine the maximum safety power. Then with the maximum safety power, the predictive value of generator impedance (GI) drop on lesion radius was explored. In the in vivo experiment, the feasibility of the maximum safety power and lesion formation was verified in the living swine. It was found that in both groups, the incidence of steam pops increased along with the raise of ablation power, and the maximum safety power was 10 W for the 1.17‐mm group and 15 W for the 2.24‐mm group. There was a strong linear correlation between GI drop and maximum lesion radius (in 1.17 mm‐10‐W group: r =.961; in 2.24 mm‐15‐W group: r =.918). In the in vivo experiment, besides ventricular fibrillation happened once, no other complications were observed, and lesions were found at both 48‐h and 8‐week groups. Conclusions: The safety power of GA should be adjusted according to the diameter of the vessel. Besides, the GI drop can predict the lesion radius during GA. [ABSTRACT FROM AUTHOR]

Background: Pulsed‐field ablation (PFA) has emerged as a nonthermal energy source for cardiac ablation, with potential safety advantages over radiofrequency ablation (RFA) and cryoballoon ablation. Objective: To report the preclinical results of a novel hexaspline PFA catheter for pulmonary vein isolation (PVI), and to verify the influence of PFA on esophagus by comparing with RFA. Methods: This study included a total of 15 canines for the efficacy and safety study and four swine for the esophageal safety study. The 15 canines were divided into an acute cohort (n = 3), a 30‐day follow‐up cohort (n = 5) and a 90‐day follow‐up cohort (n = 7), PVI was performed with the novel hexaspline PFA ablation catheter. In the esophageal safety study, four swine were divided into PFA cohort (n = 2) and RFA cohort (n = 2), esophageal injury swine model was adopted, the esophagus was intubated with an esophageal balloon retractor, under fluoroscopy, the DV8 device was inflated with a mixture of saline and contrast and rotated to displace the esophagus rightward and anteriorly toward the ablation catheter in the inferior vena cava (IVC) and right inferior pulmonary vein (PV). Nine PFA applications were delivered at four locations on IVC and two locations on the right inferior PV in the PFA cohort, six RFA applications were delivered at each location in the RFA group. Histopathological analysis of all PVs, esophagus, IVC, and the adjacent lungs was performed. Results: Acute PV isolation was achieved in all 15 canines (100%), with energy delivery times of less than 3 min/animal. In the 30 and 90 days group, the overall success rates were 88.9% and 88.5% per PVs, respectively. Two right superior pulmonary veins (RSPVs) in the 30‐day group, two RSPVs and one left superior PV in the 90‐day group with recovered potentials. At follow‐up, gross pathological examination revealed the lesions around the PVs were continuous and transmural. Masson's trichrome staining revealed the myocardial cells in the PVs became fibrotic, but small arteries and nervous tissue were preserved. Results of swine esophageal injury model revealed the esophageal luminal surface was smooth and without evidence for esophageal injury in the PFA group, whereas obvious ulceration was detected on the esophagus tunica mucosa in the RFA group. Conclusion: In the chronic canine study, PFA‐based PVI were safe and effective with demonstrable sparing of nerves and venous tissue. Compared with RFA, there was also good evidence for safety of PFA, avoiding PV stenosis and esophageal injury. This preclinical study provided the scientific basis for the first‐in‐human endocardial PFA studies. [ABSTRACT FROM AUTHOR]

The article focuses on the evolution and clinical applications of cardioneuroablation. Topics discussed include the identification of ganglionic plexi (GP) using spectral analysis, anatomical ablation techniques, and the utility of extracardiac vagal stimulation (ECVS) for assessing vagal denervation effectiveness.

The article focuses on evaluating the safety and efficacy of the PolarX cryoballoon system for treating paroxysmal atrial fibrillation. Topics discussed include the design differences between PolarX and standard cryoablation systems, procedural outcomes, and the need for comparative studies with existing technologies to assess real-world effectiveness and potential risks.

The article describes the case of a 45-year-old gentleman with documented narrow QRS tachycardia and structurally normal heart who underwent electrophysiology study with the intent of radiofrequency ablation. Topics include observation on the narrow QRS tachycardia, differential diagnosis for this narrow QRS tachycardia, and analysis of the repeated termination of the tachycardia after the subsequent His which occurred on time with His refractory ventricular premature depolarization (VPD).

Background: Recurrence rates of atrial fibrillation (AF) remain high even after complete wide area circumferential pulmonary vein isolation (PVI). In recent years adjunct posterior wall isolation (PWI) has been performed in patients with more persistent forms of AF but the benefits remain unclear. Aim: The objective of this meta‐analysis was to evaluate the efficacy of adjunct posterior wall isolation in reducing recurrence rates of AF using cryoballoon ablation (CBA). Methods: We searched PubMed, Google Scholar, Clinicaltrials.gov and Cochrane CENTRAL. We included studies comparing PVI to PVI + PWI in patients with either persistent or paroxysmal AF (PAF) undergoing CBA. After data extraction and quality assessment of the studies, we assessed recurrence rates of atrial tachy‐arrhythmias (AF, atrial flutter, and atrial tachycardia) as well as total ablation time and procedural adverse events. Risk ratio (RR), mean difference (MD), and 95% confidence interval (CI) were calculated using Review Manager. Results: Concomitant PWI exhibited a substantial reduction in the risk of AF recurrence (RR: 0.51; 95% CI: 0.42–0.63, p <.00001), as well as all atrial arrhythmias (RR: 0.58; 95% CI: 0.49–0.68, p <.00001). On subgroup analysis, in patients with only PAF, adjunct PWI resulted in significant reduction in recurrence risk of AF (RR: 0.56; 95% CI: 0.41–0.76, p =.0002) as well. There was no significant difference in adverse events between both groups (RR: 0.90; 95% CI: 0.44–1.86; p =.78), whereas total ablation time was significantly increased in PVI + PWI group (MD: 21.75; 95% CI: 11.13–32.37, p <.0001). Conclusion: Adjunct PWI when compared to PVI alone decreases recurrence rates of atrial fibrillation after CBA of patients with persistent as well as paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Background: A 70‐year‐old man revealed a rare type of atrioventricular nodal re‐entrant tachycardia (AVNRT) involving distinct retrograde pathways, superior slow pathway, and inferolateral left atrial slow pathway. Result: Radiofrequency ablation was successfully performed on the noncoronary cusp and in the left atrium, respectively, to eliminate the tachycardias. Discussion and Conclusion: Due to the anomalous electrical conduction patterns, careful diagnosis and ablation strategies were necessary to avoid the risk of atrioventricular block. These findings underscore the diversity and complexity of AVNRT and highlight the importance of tailored therapeutic approaches. [ABSTRACT FROM AUTHOR]

Background: Since the local impedance (LI) of the ablation catheter reflects tissue characteristics, the efficacy of higher power (HP) compared to lower power (LP) in LI‐guided ablation may differ from other index‐guided ablations. Objective: This study aimed to assess the efficacy of HP ablation in LI‐guided ablation of atrial fibrillation (AF). Methods: A prospective observational study was conducted, enrolling patients undergoing de novo ablation for AF. Pulmonary vein isolation was performed using point‐by‐point ablation with a RHYTHMIA HDxTM Mapping System and an open‐irrigated ablation catheter with mini‐electrodes (IntellaNav MIFI OI). Ablation was stopped when the LI drop reached 30 ohms, three seconds after the LI plateaued, or when ablation time reached 30 s. To balance the baseline differences, a unique method was used in which the power was changed between HP (45 W to anterior wall/40 W to posterior wall) and LP (35 W/30 W) alternately for each adjacent point. Results: A total of 551 ablations in 10 patients were analyzed (HP, n = 276; LP, n = 275). The maximum LI drop was significantly larger (HP: 28.3 ± 5.4 vs. LP: 24.8 ± 6.3 ohm), and the time to minimum LI was significantly shorter (HP: 15.0 ± 6.3 vs. LP: 19.3 ± 6.6 s) in the HP setting. The unipolar electrogram analysis of three patients revealed that the electrogram indicating transmural lesion formation was observed more frequently in the HP setting. Conclusion: In LI‐guided ablation, the HP could achieve a larger LI drop and shorter time to minimum LI, which may result in more transmural lesion formation compared to a LP setting. [ABSTRACT FROM AUTHOR]

Introduction: To investigate the optimal range of quantitative ablation index (AI) value during superior vena cava (SVC) electrical isolation by radiofrequency catheter ablation (RFCA). Methods: First, in a development cohort of patients with atrial fibrillation (AF), the RFCA with 40 W was performed to complete SVC isolation guided by the conduction breakthrough point from the right atrium to SVC. Then, the range of AI value was calculated by offline analysis on different segments of SVC. Lastly, for the validation of AF patients, the safety and effectiveness of SVC isolation with the optimized target range of AI value were evaluated with an additional adenosine test. Results: A total of 101 patients with AF were included in the study (44 patients in the development cohort/57 in the validation cohort). The segmental ablation strategy was applied in 70% of the patients. According to the offline analysis of the AI values in the development cohort, the target AI value range was set as 350–400. The success rate of SVC isolation in the validation cohort was significantly higher than that in the exploration cohort (100% vs. 90.9%, p =.02), and no complications occurred in the exploration cohort. During the adenosine test, the recovery rate of electrical conduction in SVC was significantly lower than that in the pulmonary vein (3.5% vs. 17.5%). Conclusion: The target AI value with a range from 350 to 400 is safe and effective for high‐power RFCA to complete SVC isolation. [ABSTRACT FROM AUTHOR]

Introduction: Pulsed‐field ablation (PFA) and the multielectrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). It is currently unknown whether these technologies differ in lesion formation and lesion extent. We compared the acute lesion extent after PVI induced by PFA and RFB by measuring low‐voltage area in high‐density maps and the release of biomolecules reflecting cardiac injury. Methods: PVI was performed with a pentaspline catheter (FARAPULSE) applying PFA or with the compliant multielectrode RFB (HELIOSTAR). Before and after PVI high‐density mapping with CARTO 3 was performed. In addition, blood samples were taken before transseptal puncture and after post‐PVI remapping and serum concentrations of high‐sensitive Troponin I were quantified by immunoassay. Results: Sixty patients undergoing PVI by PFA (n = 28, age 69 ± 12 year, 60% males, 39.3% persistent atrial fibrillation [AF]) or RFB (n = 32, age 65 ± 13 year, 53% males, 21.9% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses was 34.2 ± 4.5 and mean number RFB applications was 8.5 ± 3 per patient. Total posterior ablation area was significantly larger in PFA (20.7 ± 7.7 cm²) than in RFB (7.1 ± 2.09 cm²; p <.001). Accordingly, posterior ablation area for each PV resulted in larger lesions after PFA versus RFB (LSPV 5.2 ± 2.7 vs. 1.9 ± 0.8 cm², LIPV 5.5 ± 2.3 vs. 1.9 ± 0.8 cm², RSPV 4.7 ± 1.9 vs. 1.6 ± 0.5 cm², RIPV 5.3 ± 2.1 vs. 1.6 ± 0.7 cm,² respectively; p <.001). In a subset of 38 patients, increase of hsTropI was higher after PFA (625 ± 138 pg/mL, n = 28) versus RFB (148 ± 36 pg/mL, n = 10; p =.049) supporting the evidence of larger lesion extent by PFA. Conclusion: PFA delivers larger acute lesion areas and higher troponin release upon successful PVI than multielectrode RFB‐based PVI in this single‐center series. [ABSTRACT FROM AUTHOR]

Introduction: Transseptal puncture (TSP) to allow for large delivery sheath left atrial (LA) access remains a challenging aspect of LA appendage closure (LAAC) in patients with prior history of TSP, thick or lipomatous septum, atrial septal aneurysms, or other complex cardiac anatomies. This study investigates the use of the VersaCross large access (VLA) system (Baylis Medical/Boston Scientific) to improve procedural efficiency of LAAC compared to the standard needle workflow. Methods and Results: Fifty LAAC procedures using WATCHMAN FLX between November 2021 and September 2022 were retrospectively analyzed comparing the VLA workflow (n = 25) to the standard needle workflow (n = 25). Study primary endpoint was time to procedural efficiency, and secondary endpoints included TSP time, acute LAAC success, fluoroscopy use, device recaptures, and periprocedural complications. Acute LAAC was successfully completed in all cases with no intraprocedural complications. TSP time was faster, but not significant, using the VLA workflow compared to the standard RF needle workflow (2.6 ± 1.1 min vs. 3.0 ± 1.8 min, p = 0.38). Time to WATCHMAN sheath in LA from TSP was 27% faster (1.5 ± 0.8 min vs. 2.1 ± 0.9 min; p = 0.03), and time to WATCHMAN release from TSP was 19% faster (10.5. ± 2.5 min vs. 13.0 ± 3.7 min; p = 0.01) with the VLA workflow. Overall procedure time was 15% faster (30.4 ± 5.1 min vs. 36.0 ± 6.6 min; p = 0.003) using VLA. Fluoroscopy time was 25% lower (4.0 ± 2.2 min vs. 5.5 ± 2.3 min; p = 0.003) and fluoroscopy dose was 60% lower (97.0 ± 91.7 mGy vs. 241.8 ± 240.6 mGy; p = 0.01) and more consistent [F‐test, p ˂ 0.0001] using the VLA workflow compared to the needle workflow. Conclusion: The VLA system streamlines LAAC procedures, improving LAAC efficiency and reducing fluoroscopy use by allowing for de novo dilation of the septum for large‐bore delivery sheaths, and reducing device exchanges and delivery sheath manipulation. [ABSTRACT FROM AUTHOR]

Introduction: Posterior wall isolation (PWI) combined with pulmonary vein isolation (PVI) has proven effective for persistent atrial fibrillation (AF). However, when performing PWI, creating transmural lesions with subendocardial ablation is sometimes difficult. Endocardial unipolar voltage amplitude had a higher sensitivity than bipolar voltage mapping for identifying intramural viable myocardium in the atria. In this study, we aimed to retrospectively investigate the correlation between the residual potential in the posterior wall (PW) following PWI for persistent AF and atrial arrhythmia recurrence using endocardial unipolar voltage. Methods: This was a single‐center observational study. Patients who underwent PVI and PWI for persistent AF in the first procedure between March 2018 and December 2021 at the Tokyo Metropolitan Hiroo Hospital were included in this study. The patients were divided into two groups based on the presence of residual unipolar PW potentials after PWI with a cutoff of 1.08 mV and the recurrence of atrial arrhythmias was compared. Results: In total, 109 patients were included in the analysis. Forty‐three patients had residual unipolar potentials after PWI and 66 patients had no residual unipolar potentials. The atrial arrhythmia recurrence rate was significantly higher in the group with residual unipolar potential (41.8% vs. 17.9%, p = 0.003). The residual unipolar potential was an independent predictor of recurrence (odds ratio: 4.53; confidence interval: 1.67–12.3, p = 0.003). Conclusion: Residual unipolar potential after PWI for persistent AF is associated with recurrent atrial arrhythmias. [ABSTRACT FROM AUTHOR]

Introduction: We describe the first case of the use of pulsed‐field ablation (PFA) to treat focal atrial tachycardia (FAT) in a pediatric patient. Methods: An 11‐year‐old girl with obesity was referred to our center for ablation of incessant atrial tachycardia. The earliest atrial activation was shown to be present in the left superior pulmonary vein. Radiofrequency ablation of FAT seems to be associated with a lower success rate and, especially, with a higher complication rate than in adult patients. Results: We performed ablation by means of a novel nonthermal energy source (PFA) that is able to reduce the risk of complications due to injury to anatomic structures surrounding the heart. After the first application, stable sinus rhythm was restored. Conclusions: PFA can be used to treat FAT arising from pulmonary veins in young children as a good alternative to RFA ablation, thereby reducing the risk of potential procedure‐related complications. [ABSTRACT FROM AUTHOR]

Introduction: Ethanol infusion into the vein of Marshall (EIVOM) is expected to be an adjunctive therapy for mitral isthmus (MI) ablation. Additionally, EIVOM can widely ablate the epicardium via the branches that extend to the left atrial posterior wall (LAPW) and facilitate LAPW isolation. This study aimed to investigate the efficacy and durability of LAPW isolation with EIVOM. Methods: Our cohort consisted of 413 patients with atrial fibrillation (AF) who underwent both LAPW and MI ablations. EIVOM was first attempted in 177 (35%) patients with adequate VOMs. The VOM was infused with 5 mL of ethanol with a double coaxial guiding catheter technique. Both ablations were performed only by radiofrequency ablation (the RF group) in the remaining 236 (57%) patients. Results: EIVOM with 5 mL of ethanol was completely achieved in 106 patients (the EIVOM group). The application duration of LAPW isolation did not differ significantly between the two groups (718 ± 276 vs. 709 ± 288 s; p =.78). LAPW debulking ablation was required in 64/106 (60%) and 176/236 (75%) patients in the EIVOM and RF groups, respectively (p <.05). However, AF‐ or atrial tachycardia‐free survival analyses revealed no significant differences between the two groups (log‐rank p =.70). Among the cases of recurrence, 17 and 38 patients underwent subsequent ablation sessions; LAPW was reconnected in 9/17 (53%) and 25/38 (53%) patients (p =.36) in the EIVOM and RF groups, respectively. Conclusion: EIVOM reduced the number of cases that required LAPW debulking ablation but did not improve the durability of LAPW isolation or clinical outcomes. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses articles in the issue on topics including Farapulse Pulse Field Ablation (PFA) System Thermal and Pathological Changes, Esophageal Temperature Changes Recorded by Circa Scientific Probe (Kirstein et al.), and other related subjects.

Introduction: Intracardiac echocardiography (ICE) reveals mobile thrombus on implantable electronic device leads in some patients undergoing electrophysiologic procedures. Methods: ICE was performed in a patient undergoing ventricular tachycardia (VT) ablation. Results: ICE showed extensive mobile thrombi on the implantable cardioverter defibrillator lead. Radiofrequency catheter ablation of VT from perimitral scar was safely performed via a retrograde aortic approach. After the procedure, chronic anticoagulation was initiated. CT‐angiography of the chest 2 months later showed no pulmonary emboli. Conclusions: The significance of these thrombi, as related to chronic pulmonary embolization, warrants further study. [ABSTRACT FROM AUTHOR]

Introduction: Patients with persistent atrial fibrillation (AF) represent a challenging population for rhythm control therapies. Catheter ablation (CA) with pulmonary vein isolation (PVI) is an effective treatment option for the reduction of the arrhythmic burden. Data regarding the comparability between radiofrequency (RF) and cryoballoon ablation (CRYO) in persistent AF are limited. Methods: This is a prospective, randomized, single‐center study designed to compare the efficacy in terms of rhythm control between RF and CRYO in persistent AF. Eligible participants were randomized 2:1 in two arms: RF and CRYO. The primary endpoint of the study was arrhythmia relapse in the early postprocedural period (first 3 months) and in the middle term follow‐up (3 months to 12 months). Secondary endpoints included procedure duration, fluoroscopy time, and complications. Results: A total of 199 patients participated in the study (133 patients in the RF arm, 66 in the CRYO arm). No statistically significant difference occurred between the two groups regarding the primary endpoint (recurrences ≤3 months: 35.5% RF vs. 37.9% CRYO, p.755, recurrences >3 months: 26.3% RF vs. 27.3% CRYO, p.999). From the secondary endpoints, CRYO was a procedure of significantly shorter duration (75.15 ± 17.21 in CRYO vs. 136.6 ± 43.33 in RF group, p <.05). Conclusion: CRYO and RF ablation appear to be equally effective for rhythm control in patients with persistent AF. CRYO ablation is advantageous in terms of procedure duration. [ABSTRACT FROM AUTHOR]

Introduction: We describe an unusual case of atrial tachycardia (AT) emanating from the left atrial appendage body (LAA), successfully treated by chemical ablation. Methods: A 66‐year‐old patient with cardiac amyloidosis and history of persistent atrial fibrillation ablation presented poorly tolerated AT with 1:1 atrioventricular nodal conduction at 135/min, despite amiodarone therapy. Three‐dimensional mapping suggested a reentrant AT from the anterior aspect of the left LAA. Results: The tachycardia could not be terminated with radiofrequency ablation. The LAA vein was then selectively catheterized and infused with Ethanol, resulting in immediate termination of tachycardia, without LAA isolation. No recurrence occurred at 12 months. Conclusion: Atrial tachycardias emanating from the LAA that are resistant to radiofrequency ablation may respond to chemical ablation of the LAA vein. [ABSTRACT FROM AUTHOR]

Introduction: Accurate localization of septal outflow tract premature ventricular contractions (PVCs) is often difficult due to frequent mid‐myocardial or protected origin. Compared with traditional activation mapping, CARTO Ripple mapping provides visualization of all captured electrogram data without assignment of a specific local activation time and thus may enhance PVC localization. Methods: Electroanatomic maps for consecutive catheter ablation procedures for septal outflow tract PVCs (July 2018–December 2020) were analyzed. For each PVC, we identified the earliest local activation point (EA), defined by the point of maximal –dV/dt in a simultaneously recorded unipolar electrogram, and the earliest Ripple signal (ERS), defined as the earliest point at which three grouped simultaneous Ripple bars appeared in late diastole. Immediate success was defined as full suppression of the clinical PVC. Results: Fifty‐seven unique PVCs in 55 procedures were included. When ERS and EA were in the same chamber (RV, LV, or CS), the odds ratio for the successful procedure was 13.1 (95% confidence interval [CI] 2.2–79.9, p =.005). Discordance between sites was associated with a higher likelihood of needing multi‐site ablation (odds ratio [OR] 7.9 [1.4–4.6; p =.020]). Median EA‐ERS distance in successful versus unsuccessful cases was 4.6 mm (interquartile range 2.9–8.5) versus 12.5 mm (7.8–18.5); (p =.020). Conclusion: Greater EA‐ERS concordance was associated with higher odds of single‐site PVC suppression and successful septal outflow tract PVC ablation. Visualization of complex signals via automated Ripple mapping may offer rapid localization information complementary to local activation mapping for PVCs of mid‐myocardial origin. [ABSTRACT FROM AUTHOR]

Introduction: Recent reports highlighted the role of epicardial connections in the development of biatrial tachycardia circuits. Methods: We reported a case of 60‐year‐old female patient who was admitted with recurrent atrial tachycardia (AT) after endocardial pulmonary vein isolation and anterior mitral line formation. Results: Epicardial activation map demonstrated fragmented continuous potentials at the Bachmann's bundle region with good entrainment response. Epicardial radiofrequency ablation terminated AT with complete block in the anterior mitral line. Conclusions: This case corroborates the data relevant to the role of interatrial connections—specifically Bachmann's bundle—in biatrial macroreentrant ATs and demonstrates that epicardial mapping is an effective method to identify the entire reentrant circuit. [ABSTRACT FROM AUTHOR]

Introduction: The Heliostar™ ablation system is a novel RF balloon ablation technology with an integrated three‐dimensional mapping system. Here, we describe our early experience and procedural outcomes using this technology for atrial fibrillation catheter ablation. Methods: We sought to comprehensively assess the first 60 consecutive patients undergoing pulmonary vein isolation using the novel HELISOTAR™ RF balloon technology including procedural outcomes. A comparison of the workflow between two different anaesthetic modalities (conscious sedation [CS] vs. general anaesthesia [GA]) was made. Procedural data were collected prospectively from two high‐volume centers (Barts Heart Centre, UK and University Hospital of Zurich, Zurich). A standardized approach for catheter ablation was employed. Results: A total of 35 patients had the procedure under CS and the remaining under GA. Mean procedural and fluoroscopy times were 84 ± 33 min and 1.1 min. The median duration of RF energy application was 7 (5–9.8) mins per patient. All veins were successfully isolated, and the median isolation time was 10 (7–15) seconds. Our cohort's rate of procedural complications was low, with no mortality within 30 days postprocedure. Conclusion: Our early experience shows that catheter ablation using the Heliostar™ technology can be performed efficiently and safely; however, long‐term data is yet to be established. Low fluoroscopy requirements, short learning curves and use of this technology with CS is possible, including the use of an oesophageal temperature probe. [ABSTRACT FROM AUTHOR]

Introduction: The assessment of the ventricular myocardial substrate critically depends on the size of mapping electrodes, their orientation with respect to wavefront propagation, and interelectrode distance. We conducted a dual‐center study to evaluate the impact of microelectrode mapping in patients undergoing catheter ablation (CA) of ventricular tachycardia (VT). Methods: We included 21 consecutive patients (median age, 68 [12], 95% male) with structural heart disease undergoing CA for electrical storm (n = 14) or recurrent VT (n = 7) using the QDOT Micro catheter and a multipolar catheter (PentaRay, n = 9). The associations of peak‐to‐peak maximum standard bipolar (BVc) and minibipolar (PentaRay, BVp) with microbipolar (BVμMax) voltages were respectively tested in sinus rhythm with mixed effect models. Furthermore, we compared the features of standard bipolar (BE) and microbipolar (μBE) electrograms in sinus rhythm at sites of termination with radiofrequency energy. Results: BVμMax was moderately associated with both BVc (β =.85, p <.01) and BVp (β =.56, p <.01). BVμMax was 0.98 (95% CI: 0.93−1.04, p <.01) mV larger than corresponding BVc, and 0.27 (95% CI: 0.16−0.37, p <.01) mV larger than matching BVp in sinus rhythm, with higher percentage differences in low voltage regions, leading to smaller endocardial dense scar (2.3 [2.7] vs. 12.1 [17] cm2, p <.01) and border zone (3.2 [7.4] vs. 4.8 [20.1] cm2, p =.03) regions in microbipolar maps compared to standard bipolar maps. Late potentials areas were nonsignificantly greater in microelectrode maps, compared to standard electrode maps. At sites of VT termination (n = 14), μBE were of higher amplitude (0.9 [0.8] vs. 0.4 [0.2] mV, p <.01), longer duration (117 [66] vs. 74 [38] ms, p <.01), and with greater number of peaks (4 [2] vs. 2 [1], p <.01) in sinus rhythm compared to BE. Conclusion: microelectrode mapping is more sensitive than standard bipolar mapping in the identification of viable myocytes in SR, and may facilitate recognition of targets for CA. [ABSTRACT FROM AUTHOR]

Introduction: Incidental left atrial appendage (LAA) isolation may occur during radiofrequency ablation of persistent atrial fibrillation (AF). The study aims to describe the mechanisms and long‐term thromboembolic risk related to incidental LAA isolation. Methods: Patients who experienced incidental LAA isolation after AF ablation were included. Culprit sites where ablation resulted in LAA isolation were identified. Thromboembolic risk despite oral anticoagulation (OAC) was compared to that in a propensity‐matched control group without LAA isolation. Results: Forty‐one patients with LAA isolation, and 82 matched patients without LAA isolation were included. The patient age, ejection fraction, LA diameter, and CHA2DS2‐VASc score were 64 ± 11 years, 55 ± 12%, 45.0 ± 7 mm and 2.62 ± 1.5, respectively. Culprit sites included the LAA base, mitral isthmus, inferior LA, Bachmann′s bundle, coronary sinus, and Marshall vein. After 4.2 ± 3.6 years follow‐up, thromboembolism occurred in 7 of 41 patients (17%) with LAA isolation versus 3 of 82 patients (4%) without isolation (log rank p <.009, HR 5.14, 95% CI [1.32–19.94], p =.02). Patients with and without thromboembolism had similar CHA2DS2‐VASc scores (2.65 ± 1.3 vs. 2.71 ± 0.76, p =.89). Thromboembolism occurred during noncompliance with or temporary discontinuation of OAC in four of the seven patients. Conclusions: Incidental LAA isolation may occur during ablation of atrial arrhythmias in the vicinity of, or even at sites remote from the appendage. Patients with incidental LAA isolation had higher rates of thromboembolism compared to patients without isolation. Since thromboembolism may occur despite prescription for OAC, the risks of LAA isolation must be weighed against clinical benefit and appendage occlusion devices should be considered in vulnerable patients. [ABSTRACT FROM AUTHOR]

The article discusses a patient with short RP tachycardia and concentric atrial activation, it discusses differential diagnoses and analyzing ventricular electrogram patterns. It highlights the importance of analyzing the pattern of ventricular electrograms to interpret responses to maneuvers and suggests that an His refractory ventricular extra stimulus (HRVES) can reset an orthodromic AV re‐entrant tachycardia (ORT) by pulling in the local ventricular activation of an accessory pathway.

The article presents a case study of a 48-year-old man with a dual atrioventricular nodal physiology that has a narrow QRS tachycardia. Scanning and stimulation showed double ventricular response and a stim-H2 interval with a diagnosis of SVT-2 as a junctional tachycardia (JT). Additional radio frequency (RF) was not applied and the patient has been free from any tachycardia for 32 months.

Background/Objectives: The QDOT‐MICRO™ catheter allows very high‐power and short‐duration (vHPSD) ablation. This study aimed to investigate lesion characteristics using different ablation settings. Methods: Radiofrequency applications (90 W/4 s, temperature‐control mode with 55°C or 60°C target) were performed in excised porcine myocardium using three different approaches: single (SA), double nonrepetitive (DNRA), and double repetitive applications (DRA). Applications were performed with an interval of 1 min for DNRA, and without interval for DRA. Results: A total of 480 lesions were analyzed. Lesion depth and volume were largest for DRA followed by DNRA and SA regardless of catheter direction (depth: 3.8 vs. 3.3 vs. 2.6 mm, p <.001 for all comparisons; volume: 176.6 vs. 145.1 vs. 97.0 mm3, p <.001 for all comparisons). Surface area was significantly larger for DRA than for SA (45.1 vs. 38.3 mm2, p <.001) and larger for DNRA than for SA (44.5 vs. 38.3 mm2, p <.001), but was similar between DRA and DNRA (45.1 vs. 44.5 mm2, p =.54). Steam‐pops more frequently occurred for DRA than for SA (15.6% vs. 4.4%, p =.004) and DNRA (15.6% vs. 6.9%, p =.061), but the incidence was similar between SA and DNRA (4.4% vs. 6.9%, p = 1). Although surface area and lesion volume were larger in lesions with steam‐pops than without steam‐pops (46.5 vs. 38.1 mm2, p =.018 and 128.3 vs. 96.8 mm3, p =.068, respectively), lesions were not deeper (pop(+): 2.5 mm vs. pop(−): 2.6 mm, p =.75). Conclusions: DNRA produces larger lesions than SA without increasing the risk of steam‐pops. DRA produces the largest lesions among the three groups, but with an increased risk of steam‐pops. Even with steam‐pops, lesions do not become deeper in vHPSD ablation. [ABSTRACT FROM AUTHOR]