BACKGROUND: High-power short-duration ablation has shown impressive efficacy and safety for pulmonary vein isolation (PVI); however, initial efficacy results with very high power short-duration ablation were discouraging. This study compared the long-term durability of PVI performed with a 90- versus 50-W power setting. METHODS: Patients were randomized 1:1 to undergo PVI with the QDOT catheter using a power setting of 90 or 50 W. Three months after the index procedure, patients underwent a repeat electrophysiology study to identify pulmonary vein reconnections. Patients were followed for 12 months to detect AF recurrences. RESULTS: We included 46 patients (mean age, 64 years; women, 48%). Procedure (76 versus 84 minutes; P =0.02), left atrial dwell (63 versus 71 minutes; P =0.01), and radiofrequency (303 versus 1040 seconds; P <0.0001) times were shorter with 90- versus 50-W procedures, while the number of radiofrequency applications was higher with 90 versus 50 W (77 versus 67; P =0.01). There was no difference in first-pass isolation (83% versus 82%; P =1.0) or acute reconnection (4% versus 14%; P =0.3) rates between 90 and 50 W. Forty patients underwent a repeat electrophysiology study. Durable PVI on a per PV basis was present in 72/78 (92%) versus 68/77 (88%) PVs in the 90- and 50-W energy setting groups, respectively; effect size: 72/78−68/77=0.040, lower 95% CI=−0.051 (noninferiority limit=−0.1, ie, noninferiority is met). No complications occurred. There was no difference in 12-month atrial fibrillation-free survival between the 90- and 50-W groups ( P =0.2). CONCLUSIONS: Similarly high rates of durable PVI and arrhythmia-free survival were achieved with 90 and 50 W. Procedure, left atrial dwell, and radiofrequency times were shorter with 90 W compared with 50 W. The sample size is too small to conclude the safety and long-term efficacy of the high and very high-power short-duration PVI; further studies are needed to address this topic. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05459831.

Introduction: According to current guidelines, pulmonary vein isolation as first‐line therapy should be considered for patients with atrial fibrillation (AF), however, optimal timing of the procedure is still unknown in patients with heart failure (HF). We aimed to evaluate the effect of early catheter ablation (CA) in patients with HF and left ventricular ejection fraction (LVEF) below 50%.Methods: We analyzed data from a structured registry comprising 227 patients with paroxysmal or persistent AF and HF with LVEF < 50% who underwent radiofrequency CA between 2015 and 2022. Early CA was defined as a procedure performed within 12 months of AF diagnosis. The median follow‐up duration was 1748 (1176.3–2353.5) days, with a minimum follow‐up of 365 days. Our endpoints were AF recurrence after a 3‐months blanking period and all‐cause mortality.Results: Among the 227 patients with a median age of 64.3 years, 97 (42.7%) experienced AF recurrence and 55 (24.2%) died during the follow‐up period. The median LVEF was 40% for early CA and 38% for delayed CA (p = .053). Early CA significantly reduced AF recurrence (HR = 0.25 [0.15–0.42], p < .001), however, the timing of procedure did not affect all‐cause mortality (p = .16). These findings were consistent regardless of AF subtype or the burden of comorbidities, as assessed by the CHA₂DS₂‐VASc score.Conclusion: The timing of CA of AF appears to be an important factor in patients with HF. Early CA reduced AF recurrence, although it does not impact all‐cause mortality. We found similar results regardless of AF subtype or burden of comorbidities.

Background and aims: Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Non-vitamin-K oral anticoagulants (NOACs) effectively reduce LAA thrombus prevalence and stroke risk. However, the optimal treatment of a NOAC-resistant thrombus remains unclear. We aimed to evaluate therapeutic strategies for resolving LAA thrombus in patients on optimal NOAC therapy. Methods: We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 with LAA thrombus on transesophageal echocardiography (TEE) despite being on optimal NOAC therapy. We assessed how the applied management strategy affected thrombus resolution. Results: Among the analyzed 120 patients, a change to a different NOAC occurred in 41% of cases, a transition to a VKA in 30%, and the supplementation with antiplatelet therapy in 11%. In contrast, 18% of the patients received unchanged therapy. Follow-up imaging at 65 [44 – 95] days showed successful thrombus resolution in 92 (77%) of cases, predicted by a lower CHA2DS2-VASc score ( p = 0.01). Any modification of antithrombotic therapy was an independent predictor of thrombus resolution (OR 5.28 [1.55–18], p = 0.01). Of the four strategies, there was a trend toward better thrombus resolution with switching to a VKA (OR 3.23 [1.03–10.1], p = 0.04). Conclusion: Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the anticoagulation strategy. In addition, transitioning from NOAC to VKA might be considered. Graphical

Introduction: Concomitant pulmonary vein isolation (PVI) and left atrial appendage (LAA) occlusion (LAAO) have become frequently used therapies. Pulsed‐field ablation (PFA), will likely be used for combined PVI plus LAAO procedures. However, there may be concerns regarding the malposition of the LAAO device attributed to the potential tissue edema after PVI. Aim: We aimed to compare the LAA's size before and after PVI performed with the pentaspline catheter, measured intraprocedural by intracardiac echocardiography or transesophageal echocardiography. Methods: We conducted a multicenter, prospective, observational study investigating PVI using the Farapulse system. The anteroposterior diameter of the left‐sided pulmonary vein (LPV), left atrial ridge, and LAA were measured before and after the PFA. Results: We enrolled 91 patients aged 63 ± 10 years, 36% were women, and 47% had paroxysmal AF. The most common comorbidities was hypertension (59%). Procedure time and left atrial dwell time were 65 (52–80) min, and 27 (24–32) min, respectively. The diameter of the LAA was not different before and after the PVI (15 [13–18] and 16 [13–19], respectively; p = 0.756). On the other hand, the diameter of the left atrial ridge (7 [6–8] and 8 [6–8]) and the LPV (13 [10–15] and 13 [11–15]) was smaller before ablation compared to the diameter after PVI ( p < 0.0001 for both). No major complications occurred. Conclusion: LAA anteroposterior diameter does not change after PVI with PFA. Although there is a significant change in the anteroposterior diameters of the LPV and the left atrial ridge, it does not seem clinically relevant. If significant edema formation is detected in a single case after PVI, postponing the LAAO procedure should be considered.

Background: Ventricular tachycardia (VT) recurrence after catheter ablation remains a concern, emphasizing the need for precise risk assessment. We aimed to use machine learning (ML) to predict 1-month and 1-year VT recurrence following VT ablation. Methods: For 337 patients undergoing VT ablation, we collected 31 parameters including medical history, echocardiography, and procedural data. 17 relevant features were included in the ML-based feature selection, which yielded six and five optimal features for 1-month and 1-year recurrence, respectively. We trained several supervised machine learning models using 10-fold cross-validation for each endpoint. Results: We observed 1-month VT recurrence was observed in 60 (18%) cases and accurately predicted using our model with an area under the receiver operating curve (AUC) of 0.73. Input features used were hemodynamic instability, incessant VT, ICD shock, left ventricular ejection fraction, TAPSE, and non-inducibility of the clinical VT at the end of the procedure. A separate model was trained for 1-year VT recurrence (observed in 117 (35%) cases) with a mean AUC of 0.71. Selected features were hemodynamic instability, the number of inducible VT morphologies, left ventricular systolic diameter, mitral regurgitation, and ICD shock. For both endpoints, a random forest model displayed the highest performance. Conclusions: Our ML models effectively predict VT recurrence post-ablation, aiding in identifying high-risk patients and tailoring follow-up strategies.

Background: Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is predominantly attributed to pulmonary vein reconnection (PVR). Predictors of AF recurrence have been widely studied; however, data are scarce on procedural parameters that predict chronic PVR. We aimed to study PVR rates and predictors of PVR. Methods: We retrospectively included 100 patients who underwent repeated ablation due to AF recurrence after initial PVI with the CARTO system. PVR was determined during the repeated procedure by electrophysiological evaluation, and initial procedural characteristics predicting PVR were studied, including adherence to the CLOSE protocol, use of high power, first-pass isolation (FPI), and baseline generator impedance (BGI). Results: Thirty-eight patients underwent initial CLOSE-guided PVI, and sixty-two underwent initial non-CLOSE PVI. A repeat procedure was performed 23 ± 16 months after the initial procedure. In total, PVR was found in 192 of 373 PVs (51.5%), and all PVs were isolated in 17/100 (17%) patients. Factors associated with all PVs being isolated were adherence to the CLOSE protocol, a higher power setting, the presence of bilateral FPI, and lower BGI (88% vs. 28%, p < 0.0001; 37.5 W vs. 30 W, p = 0.0276; 88.2% vs. 40.4%, p = 0.0007; and 127.6 Ω vs. 136.6 Ω, p = 0.0027, respectively). In initial procedures with adherence to the CLOSE protocol, the FPI rate was significantly higher (73.7% vs. 25%, p < 0.0001), while there were no significant differences in terms of procedure time and left atrial dwell time (81 vs. 85 min, p = 0.83; and 60 vs. 58 min, p = 0.08, respectively). BGI ≥ 130 Ω (AUC = 0.7403, sensitivity: 77.1%, specificity: 68.8%, p = 0.0032) was associated with a significantly higher probability of PVR (OR = 6.757; p < 0.0001). In multivariable analysis, independent predictors for PVR were non-adherence to the CLOSE protocol and BGI ≥ 130 Ω. Conclusions: Our findings indicate that adherence to the CLOSE protocol and baseline generator impedance < 130 Ω during AF ablation are independent predictors of PVI durability.