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Funding Acknowledgements Type of funding sources: None. Introduction The creation of an artificial intelligence imaging algorithm, the CARTOSOUND FAM Module, shows promise in enhancing current intracardiac echocardiography (ICE) practices, particular in atrial fibrillation (AF) ablation. However, there is a gap of knowledge associated with how to best optimize current practices. This study aims to provide workflow recommendations based on a high-volume US center. Methods The CARTOSOUND FAM Module is an automated version of the legacy CARTOSOUND Module. It incorporates an automatic algorithm that enables automatic detection of cardiac anatomy using a series of 2D ultrasound views. The left atrial (LA) algorithm uses a series of 2D ultrasound frames acquired from the right atrium (RA)/fossa ovalis and the RVOT to: create a 3D volume reconstruction of the LA anatomies (LA Body, LAA, LSPV, LIPV, RSPV, and RIPV), provide 3D auto-segmentation for the relevant anatomical structures, generate 2D auto-contours that are overlaid on the corresponding 2D ultrasound frames, and demonstrate 2D auto-tagging for the relevant anatomical structures. Best practice recommendations have been collected and summarized. Results The required input for the CARTOSOUND FAM algorithm: 2D ULS distinct frames, with full spatial coverage of the LA body and its adjacent key anatomical structures (LAA and PVs), with at least 2 different views for each structure, and preferably clearly visualizing the ostium of the PV’s and LAA. The 2D clips should be acquired while the SOUNDSTAR® catheter is positioned in the RA and/or the RVOT. The selected frames within the ULS clip should be gated at the end-expiration phase and to the LA max volume (). LA frames with a temporal resolution of ~20 msec just before the opening of the mitral valve at the time of maximal atrial volume (end atrial diastole). The selected frames within the ULS clip should be with depth 90-140mm. The LA anatomy shall not have uncommon anatomical variation (e.g. 5th PV). There shall be no map shift between the ULS data (frames) and the magnetic data (FAM, VISITAGs, EA points, etc.) in the CARTOSOUND® clinical procedure. Conclusion This study successfully reports on best workflow practices in using the CARTOSOUND FAM Module in conjunction with ICE. Further studies evaluating the safety and efficiency are required to validate reproducibility these recommendations.

Funding Acknowledgements Type of funding sources: None. Background The recent PARTITA trial showed a net clinical benefit of early ventricular tachycardia (VT) ablation in patients with implantable cardioverter defibrillator (ICD) experiencing appropriate shocks. The PARTITA trial analysis, however, was performed in transvenous ICD recipients and data regarding its generalizability in subcutaneous ICD (S-ICD) recipients are lacking. Purpose To test whether VT ablation after an ICD shock or a hospitalization for slow VT impacts long-term clinical outcomes in S-ICD recipients. Methods All patients experiencing an ICD shock or a hospitalization for slow VT (index event) in the multicenter, international, physician-initiated, real-world iSUSI (International SubcutaneouS Implantable Cardioverter Defibrillator) registry were included in the study. Time zero was set as time of first ICD shock / slow VT hospitalization. Patients were stratified based on performance of VT ablation after the index event (VTA+ vs VTA- cohorts). The primary outcome was a combination of device-related appropriate shocks, slow VTs, and cardiovascular mortality during follow-up. Secondary outcomes were device-related appropriate shocks, slow VTs and cardiovascular mortality, taken individually. Results Among 1701 patients enrolled in the iSUSI registry, n=211 were included in this study (n=178 experiencing appropriate shocks; n=33 with slow VTs). After the index event, n=58 (27.5%) underwent VT ablation (VTA+ cohort). No significant differences regarding baseline characteristics between VTA+ and VTA- cohorts were observed: mean age 47.3±16.0 years (VTA+) vs 47.9±17.0 years (VTA-), p=0.799; males 82.8% (VTA+) vs 82.4% (VTA-), p=0.945; mean LVEF 43.8±13.2% (VTA+) vs 42.3±15.5% (VTA-), p=0.530; underlying ischemic cardiomyopathy 31.0% (VTA+) vs 32.7% (VTA-), p=0.8.19; primary prevention implant 36.2% (VTA+) vs 43.4% (VTA-), p=0.434; median number of shocks at index time n=2 [1-4] (VTA+) vs n=2 [1-3] (VTA-), p=0.590. Over a median follow-up of 17.3 [10.4–34.8] months, the combined primary outcome was experienced by 46 (21.8%) patients (Figure 1). VT ablation performance was associated with significantly lower event rates (8.6% vs 26.8%; HR 0.215 [CI 0.100–0.637]; p=0.004), although only a trend towards significance of cardiovascular mortality was observed (HR 0.168 [CI 0.020–1.252]; p=0.081). Among VT ablation, LVEF and ischemic cardiomyopathy, which resulted significantly associated with the primary combined outcome at univariate analysis, only VT ablation remained significantly associated with the outcome of interest at multivariate analysis (HR 0.264 [CI 0.104-0.672], p=0.005) (Figure 1). Survival analysis plotted using Kaplan Meier curves has been reported in Figure 2. Conclusions In a real world registry of S-ICD recipients, VT ablation post ICD shocks or hospitalizations for slow VTs was associated with a combined improved arrhythmic and mortality outcome at long-term follow-up.

Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage electrical isolation (LAA) is an important adjunctive ablation strategy in patients with nonparoxysmal atrial fibrillation. If impaired mechanical function following isolation is observed, long-term oral anticoagulation (OAC) or, as an alternative, LAA occlusion are required. Although focal electrical potentials from the LAA do not result in normalization of appendage mechanical function, they may potentially be a source of arrhythmogenic triggers. Those focal areas might be challenging to ablate after LAA occlusion device implantation. Purpose We sought to report the incidence of focal electrical potentials in patients with a previously isolated LAA and transesophageal echocardiography (TEE) evidence of severely impaired LAA mechanical function undergoing endocardial LAA occlusion. Methods In 124 patients undergoing LAA occlusion following LAA isolation, a circular mapping catheter (CMC) was used before occlusion to document any residual LAA electrical activity. Results At preprocedural TEE, the median LAA contraction velocity was 0.13 m/s (IQR: 0.05-0.19) and was significantly impaired in all patients. Of the 124 patients (mean age: 69±8 years; 71.7% males), 61 (49.2%) did not display any evidence of residual LAA electrical activity. In the remaining 63 (50.8%) patients, residual electrical potentials resulting in LAA reconnection were recorded on the CMC positioned into the appendage. On average, 4.9±1.7 radiofrequency energy applications (45W, mean duration of each RFA: 14.2±3.4s) were required to re-achieve complete isolation. Subsequent appendage occlusion was successful in all patients. No leaks ≥5mm and 3 (2.4%) 3-4mm-leaks were documented at 45day-TEE. Conclusions Focal electrical activity from the LAA was documented in approximately half of our patients. Although focal electrical potentials do not result in normalization of LAA mechanical function, they may potentially act as arrhythmogenic triggers. Since it may be challenging after device implantation, assessment and ablation of those areas should be considered before occlusion device deployment.

Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal-induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF-induced tissue retraction have never been reported. Purpose To quantify the anatomical changes of the LAA ostium following RF-based LAAei. Methods Thirty-four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and apx 6 months after (follow-up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Results Among 43 AF patients (67±6yrs, 72.1% males), the LAA morphology was classified as chicken wing in 19 (44.2%) patients, windsock in 12 (27.9%), cactus in 8 (18.6%), and cauliflower in 4 (9.3%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 17±6 minutes of RF at a power of 45W. Follow-up TEE was performed 294±136 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.02-0.18) and was significantly impaired in all patients. At follow-up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone was -24.4% and -22.5%, respectively. Box-Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig.1. Conclusion RF led to a >20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

Funding Acknowledgements Type of funding sources: None. Background Differently from catheter ablation (CA) of atrial fibrillation (AF), outcome data on CA of atrial re-entrant arrhythmias are scarce. Purpose We sought to evaluate predictors of recurrence at follow up in this setting. Methods We analysed consecutive patients undergoing mapping and CA left atrial tachyarrhythmia. Three-dimensional high-density activation and voltage maps were created for each investigated tachycardia by means of CARTO® system. Left atrial (LA) size was measured as the anteroposterior diameter on parasternal long axis view on transthoracic echocardiogram. Severe LA enlargement was defined for LA diameter >47 mm in women and >52 mm in men in accordance with guidelines. Results Eighty-eight patients were considered (67 ± 9 years old, 45% males) undergoing 94 CA procedures (1.1 ± 0.3 per patient). Most patient had past medical history of pulmonary vein isolation (57%). In the investigated population, 120 tachycardia morphologies were mapped and ablated. Acute procedural success was achieved in 97% of cases without any major complication. After a mean follow-up of 17 ± 11 months, the overall freedom from atrial arrhythmia was 58% and 65% after single and repeat procedures, respectively. Severe LA enlargement was the only variable associated with arrhythmia recurrence at follow-up and it was consistent after single and repeat procedures (Figure 1 A-B). Conclusion CA of complex left atrial tachyarrhythmia is safe and effective, and the mid- and long-term outcome is improved when LA is not severely enlarged. CA of should therefore be considered early in this patient population to achieve better clinical outcome.

Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage (LAA) imaging is critical during percutaneous occlusion procedures. 3D-intracardiac echocardiography (ICE) features direct visualization of LAA from multiple cross-sectional planes at a time. Purpose To report procedural success of 3D-ICE-guided LAA occlusion and the correlation between pre-procedural transesophageal echocardiography (TEE) and intraprocedural 3D-ICE for LAA sizing. Methods Among 274 patients undergoing LAAO, periprocedural ICE guidance was achieved via a commercially available 2D-ICE catheter (220 patients) or a novel 3D-ICE one (54 patients; Fig.1). Primary endpoint was a composite of procedural success and LAA sealing at follow-up TEE. Secondary endpoint was a composite of periprocedural device recapture/resizing plus presence of leaks≥3mm at follow-up TEE. Results 3D-ICE measurements of maximum landing zone correlated highly with preprocedural TEE reference values [Pearson’s: 0.94; p The agreement between 3D-ICE-based device selection and final device size was 96.3% versus 79.1% with 2D-ICE (p=0.005). The incidence of the primary endpoint was 98.1% with 3D-ICE and 97.3% with 2D-ICE (p=0.99). 2D-ICE patients had a trend towards a higher incidence of periprocedural device recapture/redeployment (31.5% vs 44.5%; p=0.09). The secondary endpoint occurred in 31.5% of 3D-ICE patients versus 45.9% of 2D-ICE ones (p=0.065). Conclusions ICE-guided LAAO showed a very high success, with no major adverse events. A very high level of agreement for LAA sizing was found between pre-procedural TEE and periprocedural 3D-ICE. 3D-ICE performed significantly better than 2D-ICE for device size selection and may provide better guidance during device deployment.

Background/Introduction Q-FFICIENCY evaluated 12-month (M) safety and efficacy of temperature-controlled paroxysmal atrial fibrillation ablation with a novel contact force-sensing, radiofrequency catheter with 3 microelectrodes and 6 thermocouples. Patients underwent pulmonary vein isolation with very high-power short-duration (vHPSD; 90 W/ up to 4 s) mode in combination with conventional-power temperature-controlled (CPTC; 25–50 W) mode. Purpose To assess procedural efficiency, safety, and 12M outcomes of participants ablated under near-zero fluoroscopy guidance compared to procedures performed with standard fluoroscopy. Methods In this US multi-centre (22 sites), non-randomised investigational study, patients underwent pulmonary vein isolation with vHPSD as primary ablation mode; CPTC was used for PV touch-up or non-PV ablation. Primary safety endpoint was incidence of primary adverse events ≤7 days post-procedure. Primary effectiveness was freedom from documented atrial tachyarrhythmia recurrence and additional pre-defined failure modes (acute failure, repeat ablation, new/higher dose anti-arrhythmic drug). Participants were followed-up through 12M post-ablation (3M blanking & 9M evaluation) to assess safety, effectiveness, and healthcare utilisation. Results Of 191 participants enrolled (63.5±10.7 years, CHA2DS2-VASc 2.4±1.5, 60.7% men), 166 were ablated with the investigational catheter, and 165 had fluoroscopy data available for inclusion in this analysis. Forty-four participants received ≤1 minute of fluoroscopy. Compared to the >1-minute of fluoroscopy cohort, the ≤1-minute group showed improved efficiencies in all procedural parameters (Table). Primary adverse event rates were similar among groups (≤1-minute, 4.5%; >1-minute, 3.3%). Kaplan-Meier estimated 12M clinical success rates (i.e., freedom from documented symptomatic recurrence) were similar regardless of fluoroscopy exposure (≤1-minute, 85.4%; >1-minute, 86.0%). Freedom from cardiovascular hospitalisation 12M post-ablation was comparable among groups (90.8% vs 88.0%). Conclusion Near-zero fluoroscopy paroxysmal atrial fibrillation ablation with the novel temperature-controlled catheter in vHPSD mode, alone or combined with CPTC, led to enhanced procedural efficiencies with good effectiveness and clinical success without comprising safety. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Biosense Webster, Inc.

Background Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal–induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF–induced tissue retraction have never been reported. Objective To quantify the anatomical changes of the LAA ostium following RF–based LAAei. Methods Thirty–four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and >6 months after (follow–up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Results Among 34 AF patients (68±7yrs, 73.5% males), the LAA morphology was classified as chicken wing in 15 (44%) patients, windsock in 10 (29%), cactus in 6 (18%), and cauliflower in 3 (9%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 16±7 minutes of RF at a power of 45–47W. Follow–up TEE was performed 257±148 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.04–0.18) and was significantly impaired in all patients. At follow–up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone were –24.4% and –22.5%, respectively. Box–Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig. 1. Conclusion RF led to a > 20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

Background Stroke prophylaxis in very high risk (CHA2DS2–VASc ≥ 5) patients with atrial fibrillation (AF) is one of the major challenges faced by physicians. Specifically, initiating direct oral anticoagulants (DOACs) in these patients poses a therapeutic conundrum due to the concomitant high risk of bleeding. Left atrial appendage occlusion (LAAO) might be a potential alternative for thromboembolic (TE) prevention; however, there are no studies comparing these two strategies in very high–risk patients. Objective To evaluate the efficacy of LAAO versus DOACs in AF patients at very high TE risk. Methods Data were extracted from two prospective databases including 1053 Watchman and 1328 DOAC patients. Watchman patients with a CHA2DS2–VASc ≥ 5 accounted for 26.3% (n = 277). In order to attenuate the imbalance in covariates, a 1:1 propensity score matching technique was used (co–variates: age, sex, CHA2DS2–VASc and HAS–BLED scores). This method resulted in 554 matched patients (277 patients per group; mean age: 79±7y; 57.4% F; CHA2DS2–VASc: 5.8±0.9). The primary endpoint was a composite of cardiovascular (CV) death, TE events (Stroke/TIA/peripheral embolism) and clinically significant bleeding. The annual TE and major bleeding risks were estimated based on the CHA2DS2–VASc score and compared with the annualized observed risk. Results After a mean follow–up of 26±7 months, total events were 55 (9.4 event rates per 100 patient–years) in LAAO group vs. 78 (14.9 event rates per 100 patient–years) in DOAC group. DOACs had a significantly higher risk of the primary endpoint (hazard ratio [HR]: 1.30; 95% confidence interval [CI]: 1.08 to 1.56; p = 0.03). TE events (HR: 1.15; 95% CI: 0.84 to 1.57; p = 0.63) and CV death (HR: 1.13; 95% CI: 0.84 to 1.54; p = 0.63) did not differ between groups. Major bleeding events were significantly lower in LAAO patients (HR: 0.75; 95% CI: 0.51 to 0.82; p = 0.04). The unadjusted estimated risk of TE events was 12.3% with LAAO and 12.4% with DOACs. The annualized incidence of TE was 3.2% with LAAO and 4.1% with DOACs, which led to a risk reduction of 74% and 67%, respectively. Conclusion In a large cohort of AF patients at very high TE risk (CHA2DS2–VASc ≥ 5), LAAO showed similar stroke prevention but a significantly lower risk of major bleeding than DOACs during a > 2year follow–up.

Background Whether residual peri–device leaks after left atrial appendage occlusion (LAAO) portend a higher risk of thromboembolism (TE), it is still a matter of debate. Objectives We report the TE risk in patients with incomplete LAA closure before and after leak closure with endovascular coils. Methods One hundred twenty–four Watchman patients with a significant (≥3mm) leak (mean age: 74 ± 9 years; 66.9% males; CHA2DS2–VASc: 4.4 ± 1.7; HAS–BLED: 3.1 ± 1) underwent LAA leak coiling. The expected annual TE risk was estimated based on the patients’ CHA2DS2–VASc and compared with the annualized incidence observed before and after coiling (Fig.1B). Results The time between LAAO and leak coiling was 8±6 months [83 patients–year (PY)]; before leak closure, 6 (4.8%) patients had a TE event (annualized rate: 7.2%). Coil deployment was successful in all cases [median n. of coils deployed: 5 (IQR: 2–10)]. Procedure time was 79 ± 40 min; the mean volume of iodinated contrast medium used was 80 ± 43mL. The overall complication rate was 2.4% (1 pericardial tamponade, 2 pericardial effusion). Follow–up TEE after 61±14 days revealed complete LAA sealing or a negligible leak in 117 cases (94.4%); the remaining 7 patients had a moderate leak. During 14±6 months post–coiling (145 PY), 1 (0.8%) patient suffered from stroke. The incidence of TE events was significantly lower after leak closure than before coiling (0.8% vs 4.8%; log–rank p = 0.02; Fig.1A). The annualized TE rates were 7.2% before and 0.7% after leak closure (Fig. 1A). According to the expected rate estimated from the patients’ CHA2DS2–VASc (9.8%), LAAO with and without significant leaks yielded to a risk reduction of 26.5% and 92.9% (Fig. 1B). Conclusions Transcatheter leak occlusion via endovascular coils was safe. LAA closure led to a significant reduction in TE events.

Background Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist and share an increased risk of thromboembolic events. CKD concomitantly contributes to several pathophysiological changes predisposing towards a pro–haemorrhagic state. Objective To evaluate the impact of kidney function on peri–procedural complications and clinical outcomes in AF patients undergoing left atrial appendage occlusion (LAAO) with a Watchman device. Methods 2124 consecutive AF patients undergoing Watchman implantation at 8 different centers were categorized into CKD stage 1 + 2 (n = 1089), CKD stage 3 (n = 796), CKD stage 4 (n = 170), CKD stage 5 (n = 69) based on the estimated glomerular filtration rate at baseline. The primary efficacy endpoint included a composite of cardiovascular (CV) mortality, stroke, transient ischemic attack, peripheral thromboembolism (TE), and major bleeding. Results A non–significant higher incidence of major peri–procedural adverse events (1.7% vs. 2.3% vs. 4.1% vs. 4.3%) was observed with worsening baseline kidney function (p = 0.14). The mean follow–up period was 13 ± 7 months [2226 patient–years (PY)]. In comparison to CKD stage 1 + 2 as a reference, the incidence of the primary endpoint was significantly higher in CKD stage 3 (log–rank p–value= 0.04), CKD stage 4 (log–rank p–value= 0.01), and CKD stage 5 (log–rank p–value= 0.001) (Fig. 1A). A non–significant increase in event rates for stroke/TIA and clinically relevant bleeding was observed among the four groups. LAAO led to a TE risk reduction of 72%, 66%, 62%, and 41% in each group (Fig. 1B). The relative risk reduction in the incidence of major bleeding was 58%, 44%, 51%, and 52%, respectively (Fig. 1C). Conclusion Patients with moderate–to–severe CKD had a higher incidence of the primary composite endpoint. The relative risk reduction in the incidence of TE and major bleeding was consistent across CKD groups, irrespective of the very different risk profiles at baseline.

Background Radiofrequency catheter ablation, a widely recognized therapeutic option for atrial fibrillation (AF) has limited success rate as it is influenced by several factors including duration of AF. Purpose We evaluated the ablation success in AF patients intervened early versus late in the disease course. Methods Consecutive AF patients undergoing their first catheter ablation in 2015–16 at our center were included in the analysis. Patients were classified into two groups based on the time to ablation after AF diagnosis; 1) early: ≤12 months and 2) late: >12 months. All received PV isolation plus isolation of posterior wall and superior vena cava. Additionally, in non-paroxysmal AF cases, non-PV triggers were identified with isoproterenol-challenge and ablated. Patients were prospectively followed up for 3 years with regular rhythm monitoring. Results A total of 752 and 1248 patients were included in the “early” and “late” group respectively. Baseline characteristics of the study population is provided in Table 1 A. At 4 years of follow-up, overall success rate off-antiarrhythmic drugs was significantly higher in the “early” group (65.4% vs 57%, p Conclusion In this large series with standardized ablation strategy, early intervention with catheter ablation was associated with higher success rate in all AF types. Funding Acknowledgement Type of funding sources: None. Table 1

Introduction This study evaluated the prevalent triggers responsible for recurrence following successful PVI in different types of atrial fibrillation (AF). Methods Consecutive AF patients undergoing repeat catheter ablation with permanently isolated PV were included in the analysis. High-dose isoproterenol challenge (20- 30μg/min for 15–20min) was used to confirm PV reconnection and identify non-PV triggers. Circular mapping catheter (CMC) was used to map the site of origin of significant ectopic activity by comparing the activation sequence of the sinus beat with that of the ectopic beat. For the coronary sinus (CS), ablation catheter was positioned at the level of the mitral valve annulus, parallel to the one positioned in the CS. Left atrial appendage (LAA) firing was detected by placing the CMC in the left superior PV and thus recording far-field potentials from the LAA. Results This prospective study included 1850 AF patients undergoing repeat AF ablation (Table 1), of which 573 (31%) had received one and the remaining 1277 patients had received 2 earlier ablations. Permanent PVI was confirmed with isoproterenol challenge. Table 1 shows the distribution of non-PV triggers. A linear increase in the number of non-PV triggers was observed from PAF to PerAF to LSPAF. Significantly higher number of LSPAF patients had detectable non-PV triggers compared to PerAF and PAF cases. Conclusion We observed a linear increase in the number of non-PV triggers in PAF to PerAF and LSPAF patients experiencing recurrence with successful isolation of PVs. As non-PV triggers are often not targeted by operators, this could be the underlying mechanism for more frequent recurrences in non-paroxysmal AF. Funding Acknowledgement Type of funding sources: None. Table 1

Introduction We investigated the ablation success of scar homogenization with combined (epicardial + endocardial) versus endocardial-only approach for ventricular tachycardia (VT) in patients with ischemic cardiomyopathy (ICM) at 5 years of follow-up. Method Consecutive ICM patients undergoing VT ablation at our center were classified into group 1: endocardial scar homogenization and group 2: endocardial +epicardial scar homogenization. Patients with previous open heart surgery were excluded. All patients underwent bipolar substrate mapping with standard scar settings defined as normal tissue >1.5 mV and severe scar Results A total of 361 (Group 1: 291 and group 2: 70) patients were included in the study (mean age: 67 years, male: 88.4%). At 5 years, significantly higher number of patients from group 2 remained arrhythmia-free (figure 1). Of those patients, 87 (45%) and 51 (89%) from group 1 and 2 respectively were off-anti-arrhythmic drugs (AAD) (p Conclusion In this series of patients with ischemic cardiomyopathy and VT, endo-epicardial scar homogenization was associated with a lower need for AAD and a significantly lower recurrence rate at 5-years of follow-up compared to the endocardial ablation alone. Funding Acknowledgement Type of funding sources: None. Figure 1

Background/Introduction The inspIRE clinical trial was designed to assess the safety and efficacy of a fully integrated biphasic pulsed field ablation (PFA) system comprised of a multi-channel generator, variable decapolar irrigated loop circular catheter, and mapping system (Figure A) for the treatment of paroxysmal atrial fibrillation (PAF). Purpose Using this novel PFA system in a multicentre clinical trial, we present the initial feasibility of electrical pulmonary vein isolation (PVI), procedural performance, and acute safety results. Methods inspIRE is a prospective, non-randomized, multi-centre study, planned to enrol up to 550 patients. PVI is performed with the novel, variable loop circular catheter, compatible mapping system and generator. Acute procedural effectiveness (entrance block in all clinically targeted PVs post adenosine/isoproterenol challenge) and the incidence of primary adverse events (PAEs) were assessed. PAEs are defined as the occurrence of cardiac tamponade/perforation, myocardial infarction, stroke/cerebrovascular accident, thromboembolism, transient ischemic attack, permanent phrenic nerve paralysis, pulmonary edema, pericarditis, and any major vascular access complications within 7 days of the ablation procedure. Additionally, any incidence of procedure or device related death, atrio-esophageal fistula, or PV stenosis (related to the ablation procedure or study catheter) within the 12M follow-up period is classified as a PAE. Results A total of 35 PAF subjects (age 59.7±10.7 years, 54.3% male) were treated across 5 European sites by 6 operators. Acute procedural success was achieved in 100% of study subjects (Figure B) with zero incidence of PAEs. Mean total procedure time was 82.9±19.9 minutes with 27.0±11.9 minutes of PFA from first to last application. Average fluoroscopy use was 10.6±6.8 minutes and LA dwell time was 45.6±15.3 minutes. Conclusion Initial results of the inspIRE trial demonstrate the acute safety and effectiveness of the new integrated IRE circular catheter, mapping system and generator for PVI in PAF patients. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): inspIRE is a company-sponsored study funded by Biosense Webster, Inc. Figure 1. (A) PFA System; (B) PVI Voltage Map

Introduction High-power short-duration (HPSD) ablation is currently being adopted by many as the preferred procedural technique in atrial fibrillation (AF). However, the optimal duration of energy delivery to successfully create a durable lesion is not clear yet. Purpose We evaluated the association of electrical reconnection with lesion-duration in HPSD ablation. Methods Consecutive AF patients undergoing repeat procedure after a prior HPSD ablation with or without isolation of left atrial appendage (LAA) and coronary sinus (CS) were included in this analysis. HPSD ablation was defined as ablation with maximum temperature setting at 420C and power delivery at 45 W for 10–15 sec (5 seconds in the CS area and posterior wall near the esophagus). In some patients a mechanical esophageal deviation tool was used to deflect the esophagus away from the ablation site. Results A total of 2249 AF patients (with LAA and CS isolation: 1451; without LAA and CS isolation: 798) receiving redo ablation after a prior HPSD procedure were included in the analysis. At the prior procedure with the HPSD approach, mean duration of ablation was significantly shorter in the area facing the esophagus compared to elsewhere (5.2±1.5 vs 12.5±1.7 seconds, p At the redo, recovery of conduction was noted in the CS (592, 40.8%), LAA (493, 34%), and PV and left atrial posterior wall (LAPW) (310, 13.8%). Of the 310 patients with LAPW reconnection, 91% (n=282) had the conduction recovered in the area facing the esophagus. In 73 patients, esophageal displacement device was used during the prior HPSD ablation. Average duration of ablation lesions in LAPW among those 73 patients was 9.2±2 seconds. PV-LAPW reconnection was observed in 3/73 (4.1%) patients. Conclusion HPSD ablation with lesion duration of Funding Acknowledgement Type of funding sources: None.

Background The dynamic changes and stability of blood biomarkers over time and after treatment are not well known. In this study, we describe changes in 12 centrally quantified known and novel cardiovascular biomarkers, prior to and 3 months after ablation for atrial fibrillation (AF). Purpose In patients enrolled in the AXAFA-AFNET5 trial, we 1) characterised changes in 12 biomarker levels pre and post-ablation, 2) ascertained if biomarker changes are consistent between males and females, and 3) identified biomarkers which predict recurrent AF post-ablation. Methods and results Of the 674 patients who were recruited and randomised, 633 received the study drug and underwent ablation. Peripheral blood samples were available for 488 patients at baseline and 434 at 3 months follow-up (median age [Q1, Q3] 64 [58, 70] years; 34% female). Between baseline (BL) and follow-up (FU), paired comparisons revealed that 3 biomarkers decreased, ANG2 (median [Q1, Q3] BL 2.185 [1.711, 3.115], FU 1.827 [1.457, 2.297] ng/mL, p Significant differences in ANG2, BMP10, NTproBNP and FABP3 were driven by patients who remained arrhythmia free at follow-up whereas biomarker levels remained unchanged in 121 patients who experienced recurrent AF (39%; Figure). Change scores were mainly consistent between males and females, however, CRP decreased significantly more in females. Recurrent AF episodes were not different between males and females (p=0.319). Cox proportional hazards model assessed the relationship of individual biomarkers at baseline for predicting recurrent AF. Elevated ANG2 (hazard ratio, HR per ng/mL [95% confidence interval] 1.214 [1.113, 1.325]), BMP10 (HR per ng/mL 1.516 [1.039, 2.214]), and NTproBNP (HR per 100 pg/mL 1.050 [1.025, 1.076]) significantly predicted increased risk for recurrent AF, after adjustment for age, sex, body mass index, hypertension, diabetes, chronic obstructive pulmonary disease, stroke, heart failure, ablation type (PVI, PVI and other, other), ablation energy (radiofrequency, cryoablation, other), and treatment arm. Conclusion In this study, most cardiovascular biomarkers are unchanged after ablation for AF, however, ANG2, BMP10, and NTproBNP decreased at follow-up. These effects are driven by patients who remained arrhythmia free and could potentially reflect improvement in vascular (ANG2), endothelial (BMP10), and myocardial load (NTproBNP) parameters post-ablation. This outcome corresponds with the observation that elevated levels of these biomarkers at baseline predict recurrent AF at 3 months. Both males and females demonstrate similar changes in biomarker profiles and benefit equally from ablation for AF. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK (German Centre for Cardiovascular Research) and BMBF (German Ministry of Education and Research) to AFNET.Additional support from European Union [grant agreement No. 633196 (CATCH ME)]. Biomarker changes

Background Coronavirus infection (COVID-19) is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited. In response to COVID-19 pandemic and overwhelmed hospital critical care and telemetry recourses, patch-based cardiac monitoring system received emergency Food and Drug Administration (FDA) approval for inpatient monitoring. A patch-based cardiac telemetry system has been shown to be useful for patient management during the COVID-19 pandemic and provides detailed analysis of cardiac rhythms. Purpose To analyze arrhythmia type and frequency in patients with COVID-19 infection, identifying arrhythmia patterns over time during hospitalization and after discharge. Methods A prospective cohort study during the COVID-19 pandemic was performed. We included patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring. A quantitative analysis including type, frequency and duration of detected arrhythmias was performed at the end of the monitoring period. Results A total of 103 patients hospitalized with COVID-19 diagnosis underwent monitoring. Quantitative reports for 59 patients were available for analysis, among those 59% were males, median age 65 (IQR 56–76) yrs. Mean wear time was 6.8±5.0 days. Arrhythmias were detected in 72.9% of patients. Majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). Episodes of AF duration >30 min were detected in 12 patients. New onset AF was noted in 15.0% of patients and was significantly associated with age (OR 1.4 for 5 yrs difference; 95% CI 1.01–2.05). Brady arrhythmias (2nd degree, 3rd degree AV bock, pause≥3 seconds) were seen in 18.7% of patients. Arrhythmias were consistently detected throughout the monitoring period in 52.9%-89.5% of patients daily (Figure 1). In 9 patients who were discharged with continued patch monitoring, 3 patients (33.3%) had arrhythmic events during their outpatient monitoring period. Conclusion A majority of patients hospitalized with COVID-19 infection had arrhythmias detected by patch cardiac monitor. Arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type similar to that seen during hospitalization. New onset AF often occurred and was associated with older age. Inpatient application of a patch cardiac telemetry with continued monitoring as outpatient is feasible and effective in detecting occult arrhythmias in patients with COVID-19 infection. Funding Acknowledgement Type of funding sources: None. Daily frequency of arrhythmias detected

Introduction Pulmonary vein isolation (PVI) is the cornerstone of ablative therapy in atrial fibrillation (AF). However, the one-year success rate after single ablation procedure is known to be up to 60%, necessitating repeat procedures in many. Purpose We evaluated the impact of different ablation strategies on procedural success at the second ablation in patients with persistent AF (PerAF). Methods Consecutive PerAF patients scheduled to undergo their second ablation were screened and only those that have received PVI plus isolation of left atrial posterior wall (PWI) and superior vena cava (SVC) at the first procedure (n=1390), were included in the analysis. At the second ablation, all reconnected structures were ablated. Additionally, based on operators' decision, non-PV triggers were targeted for ablation. Patients were classified into two groups based on the ablation strategy: group 1: Re-isolation of reconnected PVs, PW, SVC and group 2: additional ablation of non-PV triggers (from inter-atrial septum, coronary sinus (CS), left atrial appendage (LAA) and crista terminalis). Arrhythmia-monitoring was performed quarterly for 1 year and biannually afterwards. Ablation success was assessed off-antiarrhythmic drugs (AAD). Results Of the 1390 patients included in the analysis, 698 were in group 1 and 692 were in group 2. In group 1, reconnected PV, PW and SVC were re-isolated in 98 (14%), 311 (44.5%) and 173 (24.8%) respectively. In 131 (18.7%) patients, in the absence of any reconnection, CS was empirically isolated. In group 2, PV, PW and SVC were re-isolated in 83 (12%), 270 (39%) and 113 (16.3%) patients respectively. Additionally, non-PV triggers were ablated in 505 (73%) and empirical isolation of LAA and CS in the absence of detectable triggers and PV reconnection was performed in 187 (27%). At 2 years of follow-up, 425 (61%) and 602 (87%) from group 1 and 2 were arrhythmia-free off-AAD (p Conclusion Including non-PV triggers as targets for ablation at the repeat procedure was associated with significantly higher success rate in persistent AF. Funding Acknowledgement Type of funding sources: None.

Background Progression from paroxysmal (PAF) to persistent atrial fibrillation (PerAF) following effective PV isolation (PVI) has important clinical implications, as it is relevant for subsequent management of the arrhythmia. Objective We evaluated risk factors responsible for progression of PAF to PerAF following successful PVI. Methods Consecutive AF patients that received their first catheter ablation as well as the first redo at our center were identified (n=1352). Patients were included in group 1 if the diagnosis was PAF at both first and redo procedure (PAF to PAF) and group 2 if PAF at index progressed to PerAF at redo. All patients received PVI plus isolation of LA posterior wall and SVC at the first procedure. Results A total of 822 patients remained as PAF at redo, whereas 530 (39%) progressed from PAF to PerAF. Clinical characteristics of the study population are presented in table 1. In multivariate analysis, BMI (OR 1.02, 1.01–1.04, p=0.04), hypertension (1.4, 1.08–1.8, p=0.01), heart failure (1.67, 1.03–2.69, p=0.03), LA size (2.75, 2.29–3.31, p Conclusion In our patients, after successful PVI, progression of PAF to PerAF was mediated by independent risk factors such as high BMI, heart failure, hypertension, larger LA size and lower LVEF. Funding Acknowledgement Type of funding source: None

Background A myocardial substrate assessment through percutaneous endomyocardial biopsy (EMB) represents an important additional diagnostic test for cardiomyopathies when uncertainties remain after non-invasive evaluation. Yet, extensive application of EMB has been limited by the low sensitivity of biopsies. Electroanatomic voltage mapping (EVM) is a promising modality for guiding Endomyocardial biopsies (EMB). Aim The aim of our study is to evaluate the diagnostic yield of EVM-guided EMB and the role of histological analysis in the diagnosis of patients with suspected cardiomyopathies and arrhythmic presentation. Methods One-hundred and sixty-two consecutive patients undergoing EMB at our Institution from 2010 to 2019 were included. Demographics, clinical data, CMR data and peri-procedural complications were retrospectively retrieved. All procedures were guided by endo-cavitary EVM. According to non-invasive data collected before proceeding with EMB a suspected clinical diagnosis was expressed and compared to histological diagnosis Results One-hundred and sixty-two patients were included in the study. Mean age of the cohort resulted 40.9±14.7 years, with 26.5% of the included patients being females. ECG alterations were present in 51.3% of the population, with the most common abnormality being T wave inversion. Sustained or non-sustained ventricular tachycardia was registered in 51 (31.5%) of the patients, while 44 (27.2%) patients were referred for frequent isolated premature ventricular complex (PVC), and 19 (11.7%) after an episode of an arrhythmogenic syncope or resuscitated cardiac arrest. Suspected ARVC (41.6%) together with acute/chronic myocarditis (28.0%) were the main clinical diagnosis leading to an invasive approach. The sampling site was the right ventricle in 116 (72.5%), the left ventricle in 31 (19.4%), and both ventricles in 13 (8.1%) patients. Biopsy samplings were judged appropriate for histological analysis in 141 (87.0%) patients. Among the analyzed samples, a diagnosis was reached in 120 patients (74.1%). In the remaining 21 cases (25.9%), the analysis yielded nonspecific histologic findings, inconclusive results, or sampling error. The biopsy allowed to confirm the clinical diagnosis in 72 (60.0%) patients, while a different diagnosis was reached in 48 (39.0%) cases (Reclassification are showed Figure 1).In particular of 67 (41.6%) patients suspected for ARVC, only 32 (22.7) reached a confirmation. Conversely, the number of patients with acute/chronic myocarditis augmented from 45 (28.0%) to 47 (33.3%). Conclusion EMB guided by EVM reached a diagnostic yield as high as 74.1%. EMB proved to be a useful tool in the clinical management of patients, as it allowed to correctly reclassify a significant number of patients who would have been misdiagnosed based only on non-invasive assessment. Sankey Diagram Funding Acknowledgement Type of funding source: None

Background Atrial fibrillation (AF) is a disease of the elderly and women typically present with AF at an older age than men do. Moreover, they tend to experience more symptoms and post-ablation recurrences, have worse quality of life and increased risk of stroke and mortality. Objective We evaluated long-term efficacy of our standard ablation approach of extended pulmonary vein isolation (PVI) in octogenarian women undergoing their first AF ablation. Methods Consecutive female AF patients aged ≥80 years receiving their first catheter ablation at our center were included in the analysis. Our standard ablation approach at the first procedure includes PVI + empirical isolation of left atrial posterior wall (LAPW) and superior vena cava (SVC). Complete abolition of all potentials rather than decrease in amplitudes was the procedural end point. Patients were prospectively monitored at regular intervals for 3 years after the index procedure with event recorders, 12-lead ECG, cardiology evaluation at office visits and 7-day Holter monitoring. Results A total of 194 patients with mean age of 84.2±1.4 years were included in the analysis. Of the 194, 120 (61.8%) had non-paroxysmal AF. All received PVI+ isolation of LAPW and SVC. Acute procedural success was achieved in 100% of cases. At 3 years of follow-up, 24 (12.4%) patients remained in sinus rhythm; 22 on- and 2 off-antiarrhythmic drugs (AAD). All of the 23 patients had paroxysmal AF as their initial diagnosis. Of the 170 patients experiencing recurrence, 147 underwent repeat ablation. PV/PW/SVC reconnection was noted in only 6 (4.1%) patients at redo. Triggers originating from non-PV sites were targeted for ablation in all. At 1.5 years after the repeat procedure, 136 (92.5%) patients were in sinus rhythm; 131 off-AAD and 5 patients on-AAD. Conclusion Extended PVI including isolation of posterior wall and SVC was not sufficient to maintain long-term sinus rhythm in majority of octogenarian women, regardless of AF type. Moreover, non-PV triggers rather than PV reconnection was the major cause of recurrence in this subset of AF population. Funding Acknowledgement Type of funding source: None

Introduction Myocarditis is a complex inflammatory disease, usually secondary to viral infections or immune system dysregulation, with extremely heterogeneous clinical manifestations. Among them, potentially life-threatening ventricular arrhythmias (VA) may present at any stage of the disease as an expression of myocardial electrical instability. Purpose Our aim was to evaluate the efficacy of radiofrequency catheter ablation (RFCA) of VA in our large cohort of myocarditis, trying to understand the predictors of RFCA success. Methods and results 144 patients (61 men; age 43 [29–54] years) with history of myocarditis with arrhythmic presentation (118 biopsy-proven, 82%) composed our population. At presentation, 26% of patients suffered of ventricular tachycardia (VT) while in 17% cardiac arrest occurred: overall 49 patients (35%) were implanted with an ICD. The median left ventricular ejection fraction (LVEF) was 58% (48–61%). An intensive non-invasive and invasive work-up was performed: 104 patients underwent cardiac magnetic resonance (CMR) that showed late gadolinium enhancement (LGE) in 67 of them (63%). In 37 patients LGE was found in the anteroseptal portion of the left ventricle: this pattern showed association with major arrhythmic relapse (VT and ventricular fibrillation) during follow up (Fig. 1; OR 4.0, CI 95% 1.14–14.1, p=0.03). 95 patients underwent endocardial RFCA, using contact electroanatomic mapping. Interestingly, in patients with anteroseptal LGE RCFA didn't affect significantly the arrhythmic relapse (OR 5, CI 95% 0.9–33, p=0.06). Otherwise RFCA prevent arrhythmic relapse in patients that showed LGE in ventricular portion other than the anteroseptal one (OR 0.027, IC 95% 0.002–0.40, p Conclusions In myocarditis patients with VA, LGE pattern predicts arrhythmic relapse during follow-up. RFCA success rate is strictly linked to scar location, being significantly higher in patients with non-anteroseptal LGE. Figure 1 Funding Acknowledgement Type of funding source: None

Background Premature ventricular complexes (PVCs) are a common clinical problem and a critical issue with regard to sports eligibility in sportsmen. Although PVCs can be considered a benign feature of the athlete's heart adaptive phenotype, they may also be the only clinical manifestation of a concealed cardiomyopathy, potentially heralding sudden cardiac death (SCD) during sports activity. The optimal diagnostic evaluation of athletes with PVCs is currently uncertain. Purpose To evaluate the diagnostic contribution and the implications for sports eligibility assessment of a thorough non-invasive and invasive work-up including electroanatomical mapping (EAM) and endomyocardial biopsy (EMB) in athletes with PVCs. Methods We conducted a prospective, single-arm, open-label double center study. All consecutive athletes presenting for evaluation at our institution after being disqualified from participating in sports due to PVCs were included in our study. These athletes underwent a baseline non-invasive diagnostic protocol with transthoracic echocardiogram and gadolinium enhanced cardiac magnetic resonance imaging (cMRI). Subsequently, an invasive diagnostic work-up was performed, including EPS with programmed electrical stimulation, EAM and EAM-guided EMB if deemed necessary. When clinically indicated, catheter ablation was performed. Sports eligibility status was re-assessed at six months' follow-up according to Italian sports medicine guidelines. Results After diagnostic evaluation, 20 subjects out of 107 (19%) had a diagnosis of heart disease, most commonly myocarditis (n=8), arrhythmogenic right ventricular cardiomyopathy (ARVC, n=7) or dilated cardiomyopathy (DCM, n=2). On multivariate logistic-regression analysis, QRS complex/T wave abnormalities on ECG (OR 23), non left bundle branch block and inferior axis PVC morphology (OR 13), echocardiogram abnormalities (OR 24) and low-voltage areas on EAM (OR 33) were significantly associated with diagnosis of a concealed cardiac disease. Nondiagnostic abnormalities on cMRI were common in this population of athletes, prevalently involving the right ventricle. EAM-guided EMB was performed in 12 subjects (11%) and catheter ablation in 56 (52.3%). After six months, 63 athletes (59%) were judged eligible to participate in competitive sports and 23 subjects (21%) were deemed eligible to participate in non-competitive sports. Conclusions Almost one fifth of sportsmen presenting with PVCs have a concealed heart disease, most commonly myocarditis or ARVC. Non-outflow tract PVCs' morphology and abnormalities on ECG, echocardiogram and EAM are predictive of structural heart disease's detection, whereas nondiagnostic findings on cMRI can be misleading in athletes. Invasive diagnostic tests, including EAM and EAM-guided EMB, play a critical role in case of diagnostic uncertainty. More than ¾ of subjects were judged eligible to participate in sports at 6 months' follow-up. Funding Acknowledgement Type of funding source: None

Background: Prone position is a valuable treatment strategy in acute respiratory distress syndrome (ARDS) and is frequently used in surgical scenarios. Nonetheless, prone position may hinder proper acquisition and interpretation of the 12-lead electrocardiogram (ECG) as there is a sparsity of data regarding standardization of lead position and interpretation. Objective: We aimed to analyze and compare ECGs in the supine and prone positions to provide guidance for adequate interpretation and clinical utility of the ECG in prone position. Methods: This was a multicenter prospective cohort study in which ECGs in the prone and supine position were compared, including patients with COVID-19 infection and healthy controls. The precordial leads for the prone ECGs were placed in the following fashion: V1 in the right paraspinal region at the level of the T7 vertebra, V2 in the left paraspinal region at the level of the T7 vertebra, V4 in the mid-scapular region at the level of the T8 vertebra (approximately bellow the tip of the scapula), V3 halfway between V3 and V4, V5 at the posterior axillary line at the level of the T8 vertebra, and V6 at the mid-axillary line at the level of T8 vertebra - same position as the V6 in the supine position. Results: A total of 45 patients with COVID-19 infection were compared with 40 healthy volunteers (48% of the patients were female, the mean age in the entire cohort was 48.8 years, and the mean BMI was 27.9). The mean heart rate, PR interval, QRS duration, QT and QTc interval, and QRS axis in the frontal plane were found to positively correlate in supine and prone ECGs. The main difference found was no correlation of the QRS amplitude between supine and prone ECGs in leads V1, V2, V3, and V4;but there was positive correlation in leads V5 and V6. Prominent Q waves were present in the anteroseptal leads (V1-V3) in the prone posterior position. In addition, T-wave inversions or flattening were observed in leads V1 and V2 were present in a majority of patients in the prone posterior position. Conclusion: ECGs performed in the prone position are an acceptable alternative to supine ECGs. Special attention and review of prior supine ECGs may be necessary for precise interpretation of the anteroseptal precordial leads which may be misleading (i.e, septal infarct).

Introduction Non-pulmonary vein (PV) triggers originating from the coronary sinus (CS) are a common finding in atrial fibrillation (AF) patients. To date, no studies have investigated the clinical impact of focal ablation versus isolation of the CS in patients presenting triggers from this area. Purpose This study analyzed the effectiveness of two different approaches for CS ablation (total isolation vs focal ablation) in persistent AF patients undergoing repeat AF ablation. Methods Consecutive persistent AF patients undergoing repeat ablation were enrolled in this prospective analysis. All patients had triggers from the CS documented during high-dose isoproterenol. Pulmonary vein antrum isolation (PVAI) extended to the posterior wall (PW) plus superior vena cava (SVC) isolation was performed in all patients at first procedure. At repeat procedure, PV, PW, and SVC were re-isolated, if needed. Focal ablation or isolation of the CS was performed based on operator's choice either at first and/or repeat procedure, along with ablation of other non-PV triggers. Patients with triggers from left atrial appendage were excluded from the study. Results Overall, 628 consecutive patients (73.4% male, age 66.9±9.0 years) were enrolled. On the basis of the CS ablation strategy, patients were categorized into two groups: Group I received CS isolation (n=389) and Group II received CS focal ablation (n=239). Major clinical characteristics were not different between groups. PV reconnection was documented in 55 (14.1%) patients of Group I and 33 (13.8%) of Group II. The incidence of procedure-related complications was similar between the two groups (10 [2.6%] in Group I vs 6 [2.5%] in Group II; p=0.9). After a follow-up of 18±8 months, 276 (71%) patients in Group I and 115 (48%) in Group II remained arrhythmia-free (p Conclusions In patients with documented triggers from the CS undergoing repeat ablation of persistent AF, isolation rather than focal ablation of the CS significantly increased freedom from atrial tachyarrhythmias in the long term.

Introduction Incomplete left atrial appendage (LAA) closure resulting in residual, significant leak is common after LAA exclusion procedures, potentially hindering an effective thromboembolic (TE) prevention. Detachable coils have found a wide range of applications for transcatheter vascular occlusion/embolization procedures. Purpose We report for the first time the feasibility and efficacy of transcatheter leak closure with detachable coils in patients with incomplete LAA closure. Methods Thirtyconsecutive high TE-riskpatients with a clinically-relevant residual leak (mean age: 72±9 years; 73.3% males; CHA2DS2-VASc: 4.3±1.5; HAS-BLED: 3.4±1.1)underwent percutaneous closure of the LAA patency via detachable coils (Interlock-35 Fibered IDC Occlusion System, Boston Scientific Inc.; Concerto Helix Detachable Coil System, ev3 Endovascular Inc; Azur Embolization System, Terumo Interventional Systems). Trans-oesophageal echocardiography (TEE) was performed at 45±15 days post-procedure to assess for residual LAA patency. Results LAA closure had been previously attempted with a Watchman device in 25 patients, an Amulet in 2 and a LARIAT in 3. At pre-procedural TEE, a moderate/severe leak was documented in 28 (93.3%) patients, a mild one in 2 (6.7%) patients. Procedure andfluoroscopy times were 73±40min and 21±15min, respectively; the mean volume of iodinated contrast medium was 80±48mL. Overall, 114 coils were released into patents' LAA (median: 3 coils/patient; IQR: 2–4). Coil deployment was successful in 98.2% of cases (112/114). The overall complication-free rate was 93.3% (28/30). There were no instances of vascular injury, TE events, device dislodgment. There was 1 major adverse device-related event in an 87-yo male, who developed pericardial tamponade requiring a pericardial window. A small pericardial effusion without hemodynamic compromise was noted in a 78-yo woman and treated conservatively. Follow-up TEE in all patients revealed complete LAA sealing or a minimal-mild leak in 28 cases (93.3%; 22 with no residual leak, 6 with a minimal-mild residual one), and a moderate residual leak in 2 patients (6.7%). Conclusions Transcatheter LAA leak occlusion via detachable coils is a safe, effective and promising approach in high TE-risk patients with incomplete LAA closure.

Context Transcatheter ablation of atrial fibrillation (AF) has undergone important development, with acceptable midterm results in terms of the safety and recurrence. A meta-analysis was performed to identify the periprocedural complications, midterm success rates and predictors of recurrence after AF ablation. Methods and results 4357 patients with paroxysmal AF, 1083 with persistent AF and 1777 with long standing AF were included. The pooled analysis showed that there was an in-hospital complication rate of tamponade requiring drainage of 0.99% (0.44–1.54; CI 99%), stroke with neurological persistent impairment of 0.22% (0.04–0.47; CI 99%), and stroke without of 0.36% (0.03–0.70; CI 99%) After a follow up of 22 (13–28) months and 1.23 (1.19–1.5; CI 99%) procedures per patient, the AF recurrence rate was 31.20% (24.87–34.81; CI 99%). The persistent AF patients exhibited a greater risk of recurrence after the first ablation (OR 1.78 [1.14, 2.77] CI 99%), but a trend towards non significance was present in the patients with more than one procedure (OR 1.69 [0.95, 3.00] CI 99%). The most powerful predictors of an AF ablation failure in the overall population were a recurrence within 30-days (OR 4.30; 2.00–10.80), valvular AF (OR 5.20; 2.22–9.50) and a left atrium diameter of more than 50mm (OR 5.10 2.00–12.90; all CI 95%). Conclusions Persistent AF remains burdened from higher recurrence rates, however not so following redo-procedures. Three predictors, valvular AF, a left atrium diameter longer than 50mm and recurrence within 30days, could be appraised to drive selection of patients and therapeutic strategy.