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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 × 10 9 /L), as compared to standard RFA (Δ3.8 ± 2.5 × 10 9 /L, p < .001), HPSD-70W (Δ2.7 ± 1.7 × 10 9 /L, p = .037), and HPSD-90W (Δ3.6 ± 2.5 × 10 9 /L, p < .001)., Conclusion: Among the four investigated ablation technologies, PFA was associated with the highest myocardial injury and the lowest inflammatory reaction., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Aims: This retrospective study sought to compare complication rates and efficacy of power-controlled very high-power short-duration (vHPSD) and conventional catheter ablation in a large cohort of patients with atrial fibrillation (AF)., Methods and Results: We analyzed 1115 consecutive patients with AF (38.7% paroxysmal, 61.3% persistent) who received first-time catheter ablation at our centre from 2015 to 2021. Circumferential pulmonary vein isolation ± additional substrate ablation using an irrigated-tip catheter was performed with vHPSD (70 W/5-7 s or 60 W/7-10 s) in 574 patients and with conventional power (30-35 W/15-30 s) in 541 patients. Baseline characteristics were well-balanced between groups (mean age 65.1 ± 11.2 years, 63.4% male). The 30-day incidence of cardiac tamponade [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598], pericardial effusion ≥ 10 mm [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598] and transient ischaemic attack [1/574 (0.17%) vs. 2/541 (0.37%), P = 0.529] was not significantly different between vHPSD and conventional ablation. No stroke, atrio-esophageal fistula, cardiac arrest or death occurred. Procedure (122.2 ± 46.8 min vs. 155.0 ± 50.5 min, P < 0.001), radiofrequency (22.4 ± 19.3 min vs. 52.9 ± 22.0 min, P < 0.001), and fluoroscopy (8.1 ± 7.2 vs. 9.2 ± 7.4, P = 0.016) duration were significantly shorter in the vHPSD group. At 12 months follow-up, freedom of any atrial arrhythmia was 44.1% vs. 34.2% (P = 0.010) in persistent AF and 78.1% vs. 70.2% in paroxysmal AF (P = 0.068)., Conclusion: vHPSD ablation is as safe as conventional ablation and is associated with an improved long-term efficacy in persistent AF., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Early recurrence of atrial tachyarrhythmia (ERAT) is common after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF), but its clinical significance in patients with persistent AF remains unclear. We sought to determine the predictive value of ERAT for rhythm outcome after RFCA for persistent AF., Methods: The study included 207 consecutive patients (mean age 66.4 ± 10.7 years, male 66.2%) with persistent and long-standing persistent AF undergoing de novo pulmonary vein isolation (± atrial substrate ablation). All patients remained off antiarrhythmic drugs. ERAT was defined as any atrial arrhythmia ≥ 30 s occurring within the first 30 days. Late recurrence (LR) was determined during follow-up visits scheduled 1, 3, 6 and 12 months post-ablation using 7-day Holter ECGs., Results: ERAT occurred in 143/207 (69.1%) patients as AF (60%) or atrial tachycardia (40%) and was persistent in 82% of cases. During a median follow-up of 22.2 months, LR occurred significantly more often in patients with ERAT than in patients without ERAT (92.3 vs. 43.8%, P < 0.001). The only independent predictors for LR were ERAT (OR 16.8, 95% CI 6.184-45.797, P < 0.001) and intraprocedural termination to sinus rhythm (OR 0.052, 95% CI 0.003-0.851, P = 0.038). Extending the blanking period from 30 to 90 days did not impact LR rates., Conclusion: ERAT following ablation of persistent AF is strongly associated with late arrhythmia recurrence, which challenges the assumption that ERAT represents merely a transient phenomenon. While limiting the blanking period to 30 days seems justified, the benefit of early re-ablations remains to be addressed in future studies., (© 2021. The Author(s).)

Background: Lesion durability and transmurality are crucial for successful radiofrequency (RF) ablation. This study provides a model of real‐time RF lesion visualization and insights into the role of underlying parameters, as local impedance (LI). Methods: A force‐sensing, LI‐sensing catheter was used for lesion creation in an ex vivo model involving cross‐sections of porcine cardiac preparations. During 60 s of RF application, one measurement per second was performed regarding lesion size and available ablation parameters. In total, 1847 measurements from n = 36 lesions were performed. Power (20–50 W) and contact force (1–5 g, 10–15 g, 20–25 g) were systematically alternated. Results: Lesion formation was most prominent in the first seconds of RF application during which nonlinear lesion growth was observed (max. 1.08 mm/s for lesion depth and 2.71 mm/s for lesion diameter). Power levels determined the extent of lesion formation in the early phase. After 20 s, lesion size growth velocity approaches 0.1 mm/s at all power levels. LI changes were also highest in the first seconds (up to – 12 Ω/s) and decreased to less than – 0.1Ω/s after prolonged application. Conclusion: Lesion formation in irrigated RF ablation is a nonlinear process. Final lesion size resulting from an RF application is mainly influenced by high rates of lesion growth in the first seconds of ablation. LI seems to be a good surrogate for differentiating changes in lesion formation. [ABSTRACT FROM AUTHOR]

Introduction: Despite advanced ablation strategies and major technological improvements, treatment of persistent atrial fibrillation (AF) remains challenging and the underlying pathophysiology is not fully understood. This study analyzed the multiple procedure outcome and safety of catheter ablation of spatiotemporal dispersions (DISPERS) detected by artificial intelligence (AI)‐guided software in patients with long‐standing persistent AF. Methods and Results: The Volta VX1 software was used for 50 consecutive patients undergoing catheter ablation for persistent AF. First, high‐density mapping (78% biatrial) with a multipolar mapping catheter was performed. In addition to pulmonary vein isolation (PVI), ablation of DISPERS was performed aiming at homogenizing, dissecting, isolating, or connecting DISPERS areas to nonconducting anatomical structures. Follow‐up contained regular visits at our outpatient clinic at 1, 3, 6, and 12 months including 7‐day Holter electrocardiograms. Patients were mainly suffering from long‐standing persistent AF (mean AF duration 50.30 ± 54.28 months). Following PVI, ablation of left atrial and right atrial DISPERS areas led to AF cycle length prolongation (mean of 162.0 ± 16.6 to 202.2 ± 21.6 ms after) and AF termination to atrial tachycardia (AT) or sinus rhythm (SR) in 12 patients (24%). No stroke or pericardial effusion occurred; major groin complications (pseudoaneurysm n = 1, atrioventricular fistula n = 1) were detected in two patients. After a blanking period of 6 weeks, recurrence of any atrial arrhythmia was documented in 26 patients (52%). The majority of patients presented with organized AT (n = 15) while AF was present in n = 9 patients and AT/AF was observed in n = 2 patients. Twenty‐two patients underwent reablation. During a mean follow‐up of 363.14 ± 187.42 days and after an average of 1.46 ± 0.68 procedures, 82% of patients remained in stable SR. Conclusion: DISPERS‐guided ablation using machine learning software (the Volta VX1 software) in addition to PVI in long‐standing persistent AF ablation resulted in high long‐term success rates regarding AF and AT elimination. Most arrhythmia recurrences were reentrant AT. After a total of 1.46 ± 0.68 procedures, freedom from AF/AT was 82%. Despite prolonged procedure times complication rates were low. Randomized studies are necessary to evaluate long‐term efficacy of dispersion‐guided ablation using AI. [ABSTRACT FROM AUTHOR]

Background: The influence of power, duration and contact force (CF) on radiofrequency (RF) lesion formation is well known, whereas data on local impedance (LI) and electrode‐tissue‐coverage (ETC) is scarce. The objective was to investigate their effect on lesion formation in an ex vivo model. Methods and Results: An ex vivo model was developed utilizing cross‐sections of porcine heart preparations and a force‐sensing, LI‐measuring catheter. N = 72 lesion were created systematically varying ETC (minor/full), CF (1–5 g, 10–15 g, 20–25 g) and power (20 W, 30 W, 40 W, 50 W). In minor ETC, the distal tip of the catheter was in electric contact with the tissue, in full ETC the whole catheter tip was embedded within the tissue. Lesion size and all parameters were measured once per second (n = 3320). LI correlated strongly with lesion depth (r = −0.742 for ΔLI; r = 0.781 for %LI‐drop). Lesions in full ETC were significantly wider and deeper compared to minor ETC (p <.001) and steam pops were more likely. Baseline LI, ΔLI, and %LI‐drop were significantly higher in full ETC (p <.001). In lesions resulting in steam pops, baseline LI, and ΔLI were significantly higher. The influence of CF on lesion size was higher in minor ETC than in full ETC. Conclusions: ETC is a main determinant of lesion size and occurrence of steam pops. Baseline LI and LI‐drop are useful surrogate parameters for real‐time assessment of ETC and ΔLI correlates strongly with lesion size. [ABSTRACT FROM AUTHOR]

Aims This retrospective study sought to compare complication rates and efficacy of power-controlled very high-power short-duration (vHPSD) and conventional catheter ablation in a large cohort of patients with atrial fibrillation (AF). Methods and results We analyzed 1115 consecutive patients with AF (38.7% paroxysmal, 61.3% persistent) who received first-time catheter ablation at our centre from 2015 to 2021. Circumferential pulmonary vein isolation ± additional substrate ablation using an irrigated-tip catheter was performed with vHPSD (70 W/5–7 s or 60 W/7–10 s) in 574 patients and with conventional power (30–35 W/15–30 s) in 541 patients. Baseline characteristics were well-balanced between groups (mean age 65.1 ± 11.2 years, 63.4% male). The 30-day incidence of cardiac tamponade [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598], pericardial effusion ≥ 10 mm [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598] and transient ischaemic attack [1/574 (0.17%) vs. 2/541 (0.37%), P = 0.529] was not significantly different between vHPSD and conventional ablation. No stroke, atrio-esophageal fistula, cardiac arrest or death occurred. Procedure (122.2 ± 46.8 min vs. 155.0 ± 50.5 min, P < 0.001), radiofrequency (22.4 ± 19.3 min vs. 52.9 ± 22.0 min, P < 0.001), and fluoroscopy (8.1 ± 7.2 vs. 9.2 ± 7.4, P = 0.016) duration were significantly shorter in the vHPSD group. At 12 months follow-up, freedom of any atrial arrhythmia was 44.1% vs. 34.2% (P = 0.010) in persistent AF and 78.1% vs. 70.2% in paroxysmal AF (P = 0.068). Conclusion vHPSD ablation is as safe as conventional ablation and is associated with an improved long-term efficacy in persistent AF. [ABSTRACT FROM AUTHOR]

Background: Femoral vascular access using the standard anatomic landmark-guided method is often limited by peripheral artery disease and obesity. We investigated the effect of ultrasound-guided vascular puncture (UGVP) on the rate of vascular complications in patients undergoing catheter ablation for atrial or ventricular arrhythmias. Methods: The data of 479 patients (59% male, mean age 68 years ± 11 years) undergoing catheter ablation for left atrial (n = 426; 89%), right atrial (n = 28; 6%) or ventricular arrhythmias (n = 28; 6%) were analyzed. All patients were on uninterrupted oral anticoagulants and heparin was administered intravenously during the procedure. Femoral access complications were compared between patients undergoing UGVP (n = 320; 67%) and patients undergoing a conventional approach (n = 159; 33%). Complication rates were also compared between patients with a BMI of >30 kg/m2 (n = 136) and patients with a BMI < 30 kg/m2 (n = 343). Results: Total vascular access complications including mild hematomas were n = 37 (7.7%). In the conventional group n = 17 (10.7%) and in the ultrasound (US) group n = 20 (6.3%) total vascular access complications occurred (OR 0.557, 95% CI 0.283–1.096). UGVP significantly reduced the risk of hematoma > 5 cm (OR 0.382, 95% CI 0.148, 0.988) or pseudoaneurysm (OR 0.160, 95% CI 0.032, 0.804). There was no significant difference between the groups regarding retroperitoneal hematomas or AV fistulas (p > 0.05). In patients with BMI > 30 kg/m2, UGVP led to a highly relevant reduction in the risk of total vascular access complications (OR 0.138, 95% CI 0.027, 0.659), hematomas > 5 cm (OR 0.051, 95% CI 0.000, 0.466) and pseudoaneurysms (OR 0.051, 95% CI 0.000, 0.466). Conclusion: UGVP significantly reduces vascular access complications. Patients with a BMI > 30 kg/m2 seem to particularly profit from a UGVP approach. [ABSTRACT FROM AUTHOR]

Aims: Bipolar radiofrequency ablation (B-RFA) has been reported as a bail-out strategy for the treatment of therapy refractory ventricular arrhythmias (VA). Currently, existing setups have not been standardized for B-RFA, while the impact of conventional B-RFA approaches on lesion formation remains unclear.Methods and Results: (i) In a multicentre observational study, patients undergoing B-RFA for previously therapy-refractory VA using a dedicated B-RFA setup were retrospectively analysed. (ii) Additionally, in an ex vivo model lesion formation during B-RFA was evaluated using porcine hearts. In a total of 26 procedures (24 patients), acute success was achieved in all 14 ventricular tachycardia (VT) procedures and 7/12 procedures with premature ventricular contractions (PVC), with major complications occurring in 1 procedure (atrioventricular block). During a median follow-up of 211 days in 21 patients, 6/11 patients (VT) and 5/10 patients (PVC) remained arrhythmia-free. Lesion formation in the ex vivo model during energy titration from 30 to 50 W led to similar lesion volumes compared with initial high-power 50 W B-RFA. Lesion size significantly increased when combining sequential unipolar and B-RFA (1429 mm3 vs. titration 501 mm3 vs. B-RFA 50 W 423 mm3, P < 0.001), an approach used in overall 58% of procedures and more frequently applied in procedures without VA recurrence (92% vs. 36%, P = 0.009). Adipose tissue severely limited lesion formation during B-RFA.Conclusion: Using a dedicated device for B-RFA for therapy-refractory VA appears feasible and safe. While some patients need repeat ablation, success rates were encouraging. Sequential unipolar and B-RFA may be favourable for lesion formation. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation in adult congenital heart disease (ACHD) patients is a critical treatment strategy for complex arrhythmias including atrial fibrillation (AF) and atrial tachycardia (AT). In addition to vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) are increasingly used in this patient population.Objective: The purpose of this study was to assess the safety of catheter ablation in ACHD patients on uninterrupted oral anticoagulation with VKA or DOAC, examining thromboembolic, bleeding, and vascular access complications.Methods: Retrospective analysis of 234 ACHD patients with simple (n = 83), moderate (n = 66), or complex (n = 85) CHD (mean age 46 years) undergoing 368 ablation procedures on uninterrupted oral anticoagulation with VKA (45.4%) or DOAC (54.6%) was undertaken. Arrhythmias were AF in 97, right AT in 181, left AT in 65, or a combination of AF and AT in 25.Results: No thromboembolic complications occurred. Major complications occurred in 4 patients (1.1%; 1 VKA, 3 DOAC), including retroperitoneal hematoma in 2 and arteriovenous (AV) fistula requiring surgical treatment in 2. Minor bleeding or vascular access complications occurred in 46 cases (12.5%), including hematomas >5 cm in 26, AV fistulas (not requiring surgical intervention) in 13, and pseudoaneurysms in 7 (thrombin injection in 3/7). Overall, no significant difference was found between DOAC (14.9%) and VKA groups (12.0%; P = .411).Conclusion: Catheter ablation in ACHD patients on uninterrupted oral anticoagulation with VKA or DOAC is feasible and safe. No thromboembolic events occurred, and major bleeding or vascular access complications were rare. No significant differences regarding minor bleeding or vascular access complications between patients on DOAC or VKA were found. [ABSTRACT FROM AUTHOR]

Background: In patients with persistent left superior vena cava (PLSVC) ablation procedures can be challenging. We sought to determine the feasibility and safety of left atrial ablations in patients with PLSVC, especially when PLSVC is unknown prior to the ablation procedure. Methods and results: In this retrospective analysis 15 adult patients (mean age 64.6 ± 14.5 years, 53.3% male) with PLSVC undergoing 27 ablation procedures for atrial fibrillation or left atrial flutter were included. In 5 (33.3%) patients PLSVC was only discovered during the procedure. Transseptal puncture (TSP) was declared "difficult" by the ablating physician in 13 of 27 (48.2%) procedures and was not successfully completed in the first attempt in two patients with known PLSVC. Once TSP was successfully completed, all relevant structures were reached both during mapping and ablation in all procedures independent of whether PLSVC was known prior to the procedure. One major complication (3.7%) occurred in 27 procedures in a patient with known PLSVC. In the patients with unknown PLSVC no complication occurred. Conclusion: In experienced hands, left atrial access and ablation in patients with PLSVC is feasible and safe, particularly with regard to patients in whom the PLSVC is unknown prior to the ablation procedure. [ABSTRACT FROM AUTHOR]

Background: Steam pops are a rare complication associated with radiofrequency (RF) ablation and are hard to predict. The aim of this study was to assess the influence of coverage between the RF ablation electrode and cardiac tissue on steam pop incidence and lesion size. Methods and results: An ex vivo model using porcine cardiac preparations and contact force sensing catheters was designed to perform RF ablations at different coverage levels between the RF electrode and cardiac tissue. During coverage level I, only the distal part of the ablation electrode was in contact with tissue. During coverage level II half of the ablation electrode, and during coverage level III the entire ablation electrode was embedded in tissue. RF applications (n = 60) at different coverage levels I–III were systematically performed using the same standardized ablation protocol. Ablations during coverage level III resulted in a significantly higher rate of steam pops (100%) when compared to ablations during coverage level II (10%) and coverage level I (0%), log rank p <.001. Coverage level I ablations resulted in significantly smaller lesion depths, diameters, and impedance drops when compared to higher coverage level ablations, p <.001. In the controlled ex vivo model, there was no difference in applied contact force or energy between different coverage levels. Conclusions: The level of coverage between RF electrode, cardiac tissue, and the surrounding fluid significantly influenced the incidence of steam pops in an ex vivo setup. Larger coverage between RF electrode and tissue resulted in significantly larger lesion dimensions. [ABSTRACT FROM AUTHOR]

Aims: The aim of this retrospective cohort study was to assess the influence of early recurrence (ER) after pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) on long‐term outcomes and to identify clinical variables associated with ER. Methods: We retrospectively collected clinical and procedural data from 1285 patients with paroxysmal AF who underwent PVI from 2011 to 2016. Kaplan‐Meier, receiver operating characteristic (ROC) curve, logistic and Cox regression analyses were performed to analyze the influence of ER on long‐term outcomes. Results: ER was observed in 13% of patients. Kaplan‐Meier analyses showed significantly different outcomes in 1285 patients with and without ER (49% vs 74%, log rank P <.01) and in 286 patients in the subgroup that underwent reablation (44% vs 79%, log rank P <.01). The hazard ratio (HR) of ER was 1.7 within 48 hours (5% of patients), 2.7 within 1 month (5%), 3.0 within 2 months (2%), and 6.4 within 3 months (1%) for late recurrence (LR), P <.01. ROC analysis (area under the curve [AUC] = 0.79) resulted in 70.3% sensitivity and 74.2% specificity for a 14‐day blanking period, and 53.1% sensitivity and 85.5% specificity for a 30‐day blanking period. Female patients (odds ratio [OR] 1.69, P <.01) and those with diabetes (OR 1.95, P =.01) were at higher risk for ER. Conclusions: ER is observed in a substantial number of patients with paroxysmal AF after PVI and has a continuous direct effect on LR according to the timing of ER. Randomized trials are required to assess the safety and effects of reablations in a shortened blanking period on long‐term outcomes. [ABSTRACT FROM AUTHOR]