Background-aimsRecently, the etiopathogenetic role of rotational activity (RotAct) in atrial fibrillation (AF) has been proposed. We designed a prospective multicenter study using CARTO Finder to evaluate the presence/distribution of RotActs in persistent AF (persAF), pulmonary vein isolation (PVI)influences on RotActs, and the impact of its elimination on top of PVI on procedural outcomes.MethodsFor this study, 76 patients with pers AF ablation were enrolled. Procedural steps involved (1) using a CARTO-Finder map to look for RotActs (physician blinded); (2) PVI; (3) using a new map to look for residual/new RotActs; (4) ablation of RotActs, if present; (5) and finally using a new map to confirm RotAct elimination. Populations were divided based on the presence or absence of structural heart disease (Group I and II) and the presence or absence (R+ and R−) of RotActs before PVI. Presence, number, and distribution of RotAct at STEP 1, the impact of PVI on RotAct at STEP 3, and maintenance of sinus rhythm (SR) during follow-up were evaluated. 56 AF patients undergoing standard ablation protocol were included as a control group.ResultsRotAct was identified in 29 (38%) patients at STEP1. RotAct did not differ between GI and GII patients. PVI significantly modified the number and localization of RotActs (p = 0.012). RotActs which were present at STEP 1 were different after PVI, with disappearance in 18 and new appearance in 5 patients. 71 patients completed a mean 13 ± 6 months follow-up and 91.5% were in stable SR. No difference in relapses was seen between R + and R- and GI and GII. RotAct ablation significantly reduced arrhythmia relapse during the follow-up compared to the control group (freedom from arrhythmia 91.5% vs. 78.6%, p = 0.025).ConclusionRotAct was present in 38% in persAF patients. PVI influenced the number and distribution of RotActs. A tailored ablation strategy provided a high success rate (91.5%) at the follow-up.

Abstract Background In recent years, interest has grown in the functional substrate underlying atrial fibrillation (AF), particularly slow conduction velocity (SC) [1-3]. Purpose To investigate the relationship between low-attenuation epicardial adipose tissue (I-EAT), aortic root and esophagus proximity to the left atrium (LA), and conduction velocities and voltage on high-density electroanatomic maps. Methods We retrospectively enrolled 22 consecutive patients undergoing AF ablation who had both cardiac CT and high-density LA mapping in sinus rhythm. Images were processed with dedicated software to identify I-EAT and aortic root and esophagus proximity to the LA endocardium (<1 mm). Predefined HU thresholds from prior literature were applied. [4] The LA was divided into segments, defined automatically according to a previously described method to ensure comparability: roof, posterior wall, septum, anterior wall and lateral wall. [3] Non suitable segments were excluded and a segment-level analysis was performed. Sinus-rhythm activation maps were acquired using a window from P-wave onset to QRS onset, with 12-ms isochrones. Slow conduction was defined as ≥3 isochrones within a 1-cm radius (propagation velocity <27 cm/s). Low voltage (LVA) was defined as bipolar potential <0.5 mV. [2, 5]. Results 258 segments from 22 patients were analyzed. 176 segments (68%) showed SC. Most SC zone were found in anterior wall (65/176; 36.9%). On univariate analysis, SC was associated with persistent AF (p=0.021), low-attenuation epicardial adipose tissue (I-EAT; p<0.001), and aortic-root proximity <1 mm (p=0.034), but not esophageal proximity <1 mm (p=0.718). In multivariable logistic regression, I-EAT (OR 3.69, 95% CI 1.9–7.0; p<0.001), aortic-root proximity (OR 3.3, 95% CI 1.3–8.4; p=0.01), and persistent AF (OR 2.1, 95% CI 1.1–3.9; p=0.02) remained independently associated with SC. [Figure 1] Eighty-three segments (32%) demonstrated low-voltage areas (LVA); 82/83 (99%) colocalized within SC zones (p<0.001). At univariate analysis, LVA was associated with I-EAT (p=0.020), aortic-root proximity (p=0.019), persistent AF (p<0.001), and female sex (p=0.03). In multivariable analysis, LVA was independently associated with SC (OR 59.3, 95% CI 7.9–447.4; p<0.001), persistent AF (OR 4.31, 95% CI 2.2–8.6; p<0.001), and female sex (OR 2.3, 95% CI 1.1–4.7; p=0.03), but not I-EAT (OR 1.62, 95% CI 0.8–3.4; p=0.20) and aortic-root proximity (OR 1.6, 95% CI 0.7–3.9; p=0.38). [Figure 1] Conclusions Aortic root proximity and low-attenuation epicardial fat are independently associated with SC in the LA. Slow conduction, female sex, and persistent AF are independently associated with LVA.Figure 1Figure 2

In recent decades, clinical practice has been founded on the principles of evidence-based medicine, where therapeutic decisions arise from the integration of clinical expertise, patient preferences, and scientific evidence derived from controlled studies and meta-analyses. The advent of artificial intelligence (AI) in health care, however, is driving a significant evolution in clinical research, owing to its ability to analyze large volumes of heterogeneous data and overcome the limitations of traditional statistical approaches. The availability of large-scale datasets, increasing computational capability, and reduced storage costs have supported the transition towards a "data-intensive" research model, progressively integrated with conventional methods. Within cardiology, arrhythmology represents one of the fields in which AI finds extensive application. The analysis of complex electrophysiological signals, data from implantable devices, advanced cardiac imaging, and clinical parameters enables the development of algorithms capable of identifying patterns not detectable by human interpretation. These tools have already demonstrated practical utility in the early diagnosis of arrhythmias, risk stratification, procedural planning and guidance for catheter ablation, prediction of response to cardiac stimulation therapies, and optimization of remote device monitoring. Among the key emerging benefits, AI promises increasingly personalized care, enabling more targeted interventions while reducing overtreatment. Furthermore, the development of "digital twins" opens the possibility of simulating patient-specific therapeutic scenarios to support complex clinical decision-making. This manuscript provides an overview of current evidence, emerging applications, and remaining challenges related to the integration of AI in arrhythmology, highlighting its potential to drive a transition towards predictive, preventive, and personalized cardiovascular medicine.

Abstract Scar-related ventricular tachycardia (VT) is sustained by patient-specific structural and functional remodeling of the ventricular substrate, and the optimal substrate-based ablation strategy remains debated. We present an image-based computational framework for conducting controlled in silico trials of VT ablation strategies. Patient-specific left ventricular electrophysiology models were generated from late gadolinium enhancement cardiac magnetic resonance images by incorporating image-derived scar, border-zone tissue with structural fibrosis, fiber orientation, and physiologically plausible Purkinje-driven sinus activation. A dedicated standalone graphical user interface was developed to perform interactive virtual ablation based on imaging-derived or simulated electrophysiological data. We implemented standardized VT reinducibility testing to compare different lesion sets in terms of residual VT inducibility and ablation burden. As a proof of concept, the framework was applied to 20 patients with ischemic or non-ischemic cardiomyopathy undergoing VT ablation. Sustained VT was inducible in 17 patients, yielding 127 sustained VT episodes and 88 unique reentrant circuits at baseline. Four substrate-based ablation strategies were compared: scar homogenization, primary deceleration-zone ablation, primary plus secondary deceleration-zone ablation, and CMR-guided scar dechanneling. All strategies significantly reduced VT inducibility compared with baseline. Scar homogenization achieved the largest reduction in residual unique sustained VTs but required the largest ablated myocardial volume. Conversely, CMR- guided scar dechanneling showed the most favorable efficiency profile by reducing VT inducibility while limiting ablated viable myocardium. The proposed framework enables quantitative comparison of ablation efficacy, ablation burden, and mechanisms of ablation success or failure in image-guided VT therapy planning.

Abstract Infections associated with cardiac implantable electronic devices (CIEDs) pose significant clinical challenges due to their life-threatening nature and complex management. Recent advancements in prevention, diagnosis, and treatment have been driven by landmark trials such as PADIT and WRAP-IT, alongside evolving diagnostic tools like [18 F]FDG PET/CT and updated diagnostic criteria (e.g., 2023 Duke-ISCVID). A combination of well-established approaches—such as leadless pacemakers, subcutaneous ICDs, and an antibiotic-eluting envelope—and evolving adjunctive strategies, including a taurolidine-containing antimicrobial agent, incision drapes, fascial plane blocks or double gloving, have broadened the spectrum of options to reduce and potentially mitigate the risk of CIED infection. While devices like leadless pacemakers, subcutaneous ICDs, and antibiotic envelopes are supported by randomized controlled trials, adjunctive measures such as taurolidine rely predominantly on observational data. To address this variation in the strength of available evidence, a modified Delphi consensus process was conducted, bringing together cardiologists and infectious disease experts to define experience-based best practices in areas where current guidelines offer limited or no specific recommendations. The consensus achieved strong agreement (≥ 80%) on key strategies, including mandatory double-gloving to reduce contamination, the use of validated risk models (e.g., PADIT, BLISTER) for tailored infection prevention employing an antibiotic eluting envelope, multidisciplinary decision-making for non-extractable infections and the use of taurolidine solutions as adjuncts to prevent CIED infection. Moderate consensus (60–79%) supported non-delayed reimplantation after lead-related endocarditis and single-session reimplantation in pacing-dependent patients under specific circumstances. However, no consensus was reached on mandating a minimum annual procedural volume (≥ 500 cases) for CIED centers, reflecting concerns about access and operator expertise. The findings emphasize the importance of personalized risk stratification, procedural innovations, and multidisciplinary collaboration in optimizing CIED infection outcomes. Areas requiring further research include the efficacy of iodophor-impregnated drapes, fascial plane blocks, and taurolidine solutions. This consensus provides a pragmatic framework for clinicians, highlighting evidence-informed strategies to mitigate infection risks and improve care for patients undergoing CIED procedures.

BACKGROUND:Reliable predictors of recurrence after catheter ablation (CA) for atrial fibrillation (AF) remain limited. We aimed to develop and validate a clinically applicable score to predict AF recurrence and procedural complexity following CA. METHODS:We conducted a prospective, single-centre observational study enrolling 402 consecutive patients undergoing CA for AF. Clinical, echocardiographic, and procedural data were collected. The primary endpoint was AF recurrence at 12 months. Predictors were identified by Cox regression. A composite score (LUCA) was developed (0-3 points). Prognostic performance was assessed using Cox regression and Kaplan-Meier analysis. An independent retrospective cohort (277 patients) served as validation cohort for external validation. RESULTS:Three predictors (LAVi, timing of ablation, AF at presentation) were independently associated with recurrence. The LUCA score stratified recurrence risk: one-year AF-free survival was 94.9% (score 0), 81.9% (1), 73.4% (2), and 30.0% (3) (log-rank p < 0.001). Each point increase corresponded to a 2.52-fold higher recurrence risk (HR 2.52, 95% CI 1.88-3.39, p < 0.001; C-index 0.69). Findings were consistent in external validation cohort (model C-index 0.776), where LUCA performed better compared to both APPLE (AUC 0.87 vs 0.77; ΔAUC 0.103, 95% CI 0.037-0.168, Z = 3.08, p = 0.002) and CHA2DS2-VASc (AUC 0.87 vs 0.56; ΔAUC 0.312, 95% CI 0.224-0.401, Z = 6.9, p < 0.001). Higher LUCA scores correlated with longer procedural time (ρ = 0.3, p < 0.001). CONCLUSIONS:The LUCA score predicts AF recurrence and procedural complexity after CA. It provides a practical and personalized tool to improve patient selection, guide procedural strategy, and optimize follow-up.

BACKGROUND:Women are frequently underrepresented in studies investigating atrial fibrillation (AF) ablation. We evaluated the acute efficacy, safety, and mid-term outcomes of de novo paroxysmal AF ablation in female patients using a pentaspline pulsed-field ablation (PFA) versus thermal-based technologies. METHODS:In a cohort of consecutive female patients with paroxysmal AF undergoing de novo pulmonary vein isolation, enrolled in the ATHENA-CHARISMA (Advanced Technologies For Successful Ablation of AF in Clinical Practice - Catheter Ablation of Arrhythmias With High-DensityMapping System in the Real WorldPractice) registries, thermal ablation systems (radiofrequency or cryoablation) were compared to the PFA by means of a propensity score matching (ratio 1:1:1). RESULTS:One-thousand one female patients (mean age 63±10 years, mean left ventricular ejection fraction 60.8±6%) were included: 376 (37.6%) underwent cryoablation ablation, 342 (34.2%) radiofrequency ablation, and 283 (28.3%) PFA. Propensity score matching yielded 684 patients (228 per group). The PFA group had significantly shorter skin-to-skin time (60 [50-75] minutes) compared with both radiofrequency (120 [90-145] minutes, P<0.001) and cryoablation (75 [60-100] minutes, P<0.001), while fluoroscopy time was similar among groups (15 [11-21] minutes for PFA, 14 [10-20] minutes for cryoablation, P=0.599 versus PFA and 14 [9-20] minutes for radiofrequency, P=0.454 versus PFA). Overall complication rate was 3.4% and it was significantly higher after thermal ablation than PFA (4.6% versus 0.9%, OR, 5.5, 95% CI, 1.3-23.5, P=0.0227). During a median follow-up of 413 [277-589] days, 139 (20.3%) patients experienced AF recurrence. The Kaplan-Meier estimated freedom from AF at 1-year follow-up was 86.8% with PFA, 84.6% with cryoablation, and 83.3% with radiofrequency (log-rank P value: 0.839). CONCLUSIONS:Among this cohort of female patients, de novo paroxysmal AF using a pentaspline PFA system demonstrated significantly shorter procedural times, and a lower complication rate compared with thermal ablation systems. One-year follow-up revealed comparable rates of AF freedom across all ablation modalities. REGISTRATION:ATHENA (Advanced Technologies For Successful Ablation of AF in Clinical Practice). URL: http://clinicaltrials.gov/; Unique identifier: NCT05617456. CHARISMA (Catheter Ablation of Arrhythmias With High-Density Mapping System in the Real World Practice). URL: http://clinicaltrials.gov/; Unique Identifier: NCT03793998.

BACKGROUND:Despite being the most effective option for maintaining sinus rhythm, atrial fibrillation (AF) catheter ablation reaches few patients. For this reason, identifying candidates with the highest likelihood of success or individualizing counselling to a specific patient to improve procedural outcome could enhance clinical benefits and cost-effectiveness. OBJECTIVE:To integrate machine learning (ML) into an outcome prediction model based on a large cohort of AF patients undergoing pulsed field ablation (PFA). METHODS:Consecutive AF patients undergoing transcatheter PFA between June 2022 and December 2024 were prospectively enrolled in the ATHENA registry. All procedures were performed with a penta-splines 12F over-the-wire PFA catheter (FARAWAVE™, Boston Scientific). Clinical and procedural variables were collected to train five predictive models estimating 1 year arrhythmic recurrence; model interpretability was assessed using SHAP (SHapley Additive exPlanations) analysis. RESULTS:The study included 1688 AF patients with a median follow-up of 365 days (interquartile range 202-393), arrhythmic recurrence occurred in 314 patients (18.6%). The Boruta algorithm identified diagnosis-to-ablation time (DAT), CHA₂DS₂-VASc score, age, and body mass index (BMI) as most significant predictors. Among the five ML models developed to predict 1 year arrhythmic recurrence probability, Random Forest achieved the best performance (AUC = 0.75, 95% CI 0.69-0.82). SHAP analysis confirmed DAT, BMI, and indexed left atrial volume as major contributors to recurrence. CONCLUSION:This is the first ML model exclusively trained and validated on AF patients undergoing PFA providing actionable insights for personalized treatment planning. Routine use of the model holds the potential to optimize patient selection and improve procedural outcome, supporting individualized counselling and outcome-driven care pathways, moving from static to interactive risk prediction. CLINICAL TRIAL REGISTRATION:Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA). URL: http://clinicaltrials.gov/ Identifier: NCT05617456.

Background: Brugada Syndrome (BrS) is a cardiac arrhythmia associated with an increased risk of ventricular arrhythmias and sudden cardiac arrest. Although the arrhythmic substrate is traditionally localized to the ventricles, atrial fibrillation (AF) is frequently observed, suggesting a shared molecular substrate between atrial and ventricular arrhythmias. C-type natriuretic peptide (CNP) and related microRNAs (miRNAs) modulate atrial and ventricular physiology, but their roles in exosomes in BrS have not been investigated. Objectives: To investigate alterations in CNP mRNA expression and changes in the expression of selected CNP-associated miRNAs implicated in AF, both analyzed in exosomes isolated from individuals with BrS and from healthy controls. Methods: Exosomes were isolated from the plasma of BrS patients without a history of overt AF and from healthy controls. In silico analyses identified CNP-targeting miRNAs implicated in AF. Exosomal CNP and CNP-related miRNAs were analyzed using Droplet Digital PCR. Results: BrS patients exhibited a significant increase in exosomal CNP mRNA expression levels compared with controls. MiR-138-5p was selectively downregulated, whereas other AF-related CNP-targeting miRNAs (miR-4443, miR-206, miR-142-5p, miR-223-5p) showed comparable levels between groups. A positive correlation between exosomal CNP and miR-223-5p and miR-4443 suggests shared regulatory pathways. Conclusions: these findings indicate that exosomal profiling may provide a more sensitive approach than conventional circulating measurements to detect molecular remodeling in BrS. The observed alterations highlight a potential shared molecular substrate between atrial and ventricular arrhythmias and may inform future studies aimed at refining diagnostics and developing targeted therapeutic strategies.

Accurate identification of the site of origin (SOO) of outflow tract ventricular arrhythmias (OTVAs) is critical for effective ablation planning. Accuracy of the existing algorithms/scores in patients with wide baseline QRS has not been previously described. This study sought to evaluate the performance of available algorithms/scores in predicting the OTVA-SOO in patients with wide baseline QRS due to intraventricular conduction abnormalities or paced rhythm (NCT06602635). Eighty-eight patients with intraventricular conduction disturbances (baseline QRS >110 ms) or a paced rhythm who underwent OTVA ablation in 9 European centers were included. The predictive performance of the existing algorithms/scores was compared using receiver operating characteristic curve analysis, accuracy, sensitivity, and specificity. Median baseline QRS duration was 122ms (114–144), sixty-five (73.9

AIMS:Data on pulsed-field ablation (PFA) for atrial fibrillation (AF) in patients with heart failure (HF) are limited. To evaluate clinical outcomes of PFA in patients with AF and HF, stratified by HF subtype. METHODS AND RESULTS:Consecutive patients undergoing first-time pentaspline PFA within the ATHENA registry were analyzed. Patients were stratified into three groups: no HF, HF with preserved ejection fraction (HFpEF, LVEF ≥50%), and HF with mildly reduced or reduced EF (HFmrEF/rEF, LVEF <50%). The primary endpoint was freedom from documented atrial arrhythmias >30 s after a 2-month blanking period. AAD use was left to physician discretion. Among 1,224 patients included (68.5% with paroxysmal AF and 31.5% with persistent AF), 176 (14.4%) had HF: 40 (3.3%) with HFpEF and 136 (11.1%) with HFmrEF/rEF. The Kaplan-Meier estimated freedom from any atrial arrhythmias at 1-year follow-up was 79.9%, with higher rate in the no-HF group (81.0%) vs the HF group (73.3%, HR = 1.5, 95% CI: 1.1-2.1, P = 0.0133). Considering separately paroxysmal and persistent AF form, paroxysmal AF patients with no sign of HF showed significantly higher freedom from atrial arrhythmias (82.2%) than patients with HF (68.6%, 2.0, 1.3-3.1, P = 0.0028), while no differences were found in patients with persistent AF (77.9% vs 76.4%, 1.1, 0.7-1.7, P = 0.7065). CONCLUSION:PFA with the pentaspline catheter appears to be an effective treatment for AF in patients with HF. Freedom from AF and atrial arrhythmias post-PFA was highest in patients with paroxysmal AF and no history of HF, with no significant differences observed in persistent AF patients. CLINICAL TRIAL REGISTRATION:Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA). URL: http://clinicaltrials.gov/Identifier: NCT05617456.

The QDOT Micro catheter allows to perform a very high-power short-duration ablation that produces wider and shallower lesions. This study aims to corroborate the evidences on the safety, acute and long-term efficacy of this catheter by providing a large real-world dataset. The AIR HPSD Registry is a multicentric prospective registry across 26 European centers that enrolled consecutive atrial fibrillation (AF) patients undergoing their first pulmonary vein (PV) isolation. In all patients a wide antrum circumferential ablation aimed at PV isolation was performed using the QDOT Micro catheter in QMode+ (90 w for 4 s) for the whole ablation or in a hybrid mode (QMode + for the posterior wall and QMode guided by ablation index for the anterior wall), according to the operators’ preference. Overall, 982 patients have been enrolled, 38

Abstract Background The subcutaneous implantable cardioverter-defibrillator (S-ICD) provides effective protection against sudden cardiac death while avoiding transvenous leads. Real-world data on the longevity of contemporary S-ICD systems are still limited. Objective To assess the real-world longevity of current-generation S-ICDs and identify factors influencing battery performance in a multicenter, remotely monitored cohort. Methods Data from 2,130 EMBLEM S-ICD devices enrolled in the LATITUDE remote monitoring network across 24 Italian centers (2015–2025) were analyzed. Devices affected by the 2019 advisory on premature battery depletion or with an implant duration <3 months (n=241) were excluded. Longevity was defined as device duration plus the estimated remaining battery life at the latest remote transmission Results Median follow-up was 2.7 years (IQR 1.5–4.1). At the latest transmission, the estimated remaining battery life was 68 ± 19%. Median estimated device longevity was 9.0 years (IQR 8.7–9.2), approximately two years longer than manufacturer projections. Shock burden was the main determinant of reduced longevity: patients experiencing ≥2 shocks per year had an estimated lifespan shorter than those without shocks (7.0 vs. 9.1 years; p<0.001) (Figure 1). The effect of in-office interrogations and remote transmissions on battery life was negligible (<0.1 year). Devices implanted for >6 years showed slightly shorter estimated longevity compared to those implanted for 1–2 years (8.9 vs. 9.3 years; p<0.001). Conclusions In a large real-world cohort, contemporary S-ICD systems showed excellent and predictable longevity, exceeding manufacturer expectations. Battery performance was minimally affected by telemetry activity, while frequent shock delivery modestly reduced lifespan.Longevity estimates for all S-ICDs

Cancer patients have not been included in landmark trials of SGLT2is in heart failure, so data on safety and effectiveness are lacking. TOSCA is a multi-center observational trial including patients with active cancer receiving SGLT2is for HF treatment. The primary endpoint was safety, and the secondary endpoint was effectiveness. Exploratory endpoints included drug–drug interactions, treatment of cancer therapy-related cardiac dysfunction (CTRCD), and changes in NT-proBNP. One-hundred and twenty-nine patients (median age 72 [range 44–92] yrs) were enrolled who had been receiving SGLT2i for a median of 3 (range 3–25) months. Prevalent etiology was drug-induced HF with HFrEF as the most frequent clinical presentation. The incidence of urinary tract infections was 1.8%, with no cases of genital infections, hypoglycemia, diabetic ketoacidosis, acute renal injury, thrombosis, or bone fractures. The mean overall EF increased (40.3% vs. 47.4%), and NYHA class improved in 19% of cases. Rates of unplanned cardiology visits (0.9%), use of i.v. diuretics (0.9%), coronary angiography (4.5%), emergency access for HF (1.8%), and new HF episodes (3.6%) were extremely low. In 11 cases (8.5%), the initiation of SGLT2i enabled continuation of anticancer therapy that would have otherwise been delayed or suspended due to HF decompensation. SGLT2is appeared effective in 34 cases of CTRCD. No drug–drug interactions were reported. SGLT2is confirmed their safety and effectiveness in active cancer patients with HF, with a potential cardioprotective effect. No new safety warnings were recorded.

BACKGROUND:Micra leadless pacemaker offers an alternative to traditional transvenous pacemakers by eliminating the risks associated with leads and device pockets. Due to the technical demands of a leadless transcatheter pacemaker, concerns initially limited the procedure to centers with on-site cardiac surgery (CS) capabilities. However, growing evidence supports its safe implementation in noncardiac surgical centers, though data comparing outcomes in these settings remain limited. AIMS:This analysis aims to evaluate the safety and feasibility of Micra leadless pacemaker implantation in centers with and without CS, assessing acute complications, device performance, and patient follow-up. METHODS:A retrospective analysis was conducted on 1899 patients who received a Micra pacemaker from May 2015 to September 2024 at 23 centers. Patients were divided into two groups: those implanted in centers with CS (CS, n = 1025) and those without (No-CS, n = 874). The primary endpoint was acute complications within 15 days postimplant, while secondary endpoints included device performance and clinical follow-up at 12 months. RESULTS:The overall acute complication rate was low at 0.6%, with no significant difference between the CS (0.5%) and No-CS groups (0.8%; p = 0.391). Procedural times were slightly shorter in No-CS centers (41.2 ± 19.8 vs. 46.1 ± 19.3 min; p < 0.001), and both groups showed comparable device performance and patient outcomes over the follow-up period. CONCLUSION:The Micra leadless pacemaker can be safely and effectively implanted in centers without CS capabilities, broadening access to this technology across diverse clinical settings.

The QDOT Micro catheter (Biosense Webster, Inc CA) enables the ablation in the Qmode+ modality (90 W for 4 sec) and/or in the Qmode modality, 50 W ablation index (AI)-guided. Both modalities of very high-power short duration (vHPSD) ablation have been described to improve procedural efficiency without compromising the efficacy and the safety of the pulmonary vein isolation (PVI). However, data from large multicentric registries are still lacking. We sought to investigate in a large cohort of atrial fibrillation (AF) patients the impact of different ablation strategies: the hybrid approach (Qmode+, 90 W for 4 sec, at the posterior wall of the left atrium and Qmode modality AI-guided at the anterior wall) vs. the ablation performed exclusively with the Qmode+ modality. The AIR HPSD Registry is a multicentric study including AF patients undergoing their first PVI procedure by mean of the QDOT Micro catheter across 22 European centers. The ablation modality (hybrid/ Qmode+) was left to operators’ preference. Overall, 917 patients have been enrolled, 72% males, 70% had paroxysmal AF, the mean age was 62±10 years. Pulmonary vein isolation was reached in 100% regardless of the ablation modality. As for the first pass isolation (FPI), the rate was significantly higher in the hybrid group compared to the Qmode+ group (78% vs. 70%, p=0.01), even when considering the right (86% vs. 79%, p=0.01) and left veins (88% vs. 82%, p=0.02) separately. The fluoroscopy time was higher in the hybrid group (380±435 vs. 204±249 sec, p<0.001) however the procedural time was similar between the two groups (110±39 min vs. 95±38 min, p=ns). Furthermore, as expected, the saline infusion volume was higher in the hybrid group (410±274 vs 225±78 ml, p<0.001). No differences in the rate of complications were observed between the two groups (1,5% vs. 0,3%, p=ns). The hybrid and the Qmode+ approaches are both highly effective and safe in achieving PVI, however the hybrid strategy significantly increases the rate of FPI without increasing the overall procedural time.