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Background: Mitral annular flutter (MAF) is the most common left atrial macro‐reentrant arrhythmia following catheter ablation of atrial fibrillation (AF). The best ablation approach for this arrhythmia remains unclear. Methods: This single‐center, retrospective study sought to compare the acute and long‐term outcomes of patients with MAF treated with an anterior mitral line (AML) versus a mitral isthmus line (MIL). Acute ablation success, complication rates, and long‐term arrhythmia recurrence were compared between the two groups. Results: Between 2015 and 2021, a total of 81 patients underwent ablation of MAF (58 with an AML and 23 with a MIL). Acute procedural success defined as bidirectional block was achieved in 88% of the AML and 91% of the MIL patients respectively (p = 1.0). One year freedom from atrial arrhythmias was 49.5% versus 77.5% and at 4 years was 24% versus 59.6% for AML versus MIL, respectively (hazard ratio [HR]: 0.38, confidence interval [CI]: 0.17–0.82, p =.009). Fewer patients in the MIL group had recurrent atrial flutter when compared to the AML group (HR: 0.32, CI: 0.12–0.83, p =.009). The incidence of recurrent AF, on the other side, was not different between both groups (21.7% vs. 18.9%; p =.76). There were no serious adverse events in either group. Conclusion: In this retrospective study of patients with MAF, a MIL compared to AML was associated with a long‐term reduction in recurrent atrial arrhythmias driven by a reduction in macroreentrant atrial flutters. [ABSTRACT FROM AUTHOR]

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

Introduction: Prediction of recurrent ventricular arrhythmia (VA) in survivors of an out‐of‐hospital cardiac arrest (OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring assessed with late gadolinium enhancement cardiac magnetic resonance (LGE‐CMR). Our study aims to characterize myocardial scarring as defined by LGE‐CMR in survivors of a VA‐OHCA and investigate its potential role in the risk of new VA events. Methods: Between 2015 and 2022, a total of 230 VA‐OHCA patients without ST‐segment elevation myocardial infarction had CMR before implantable cardioverter‐defibrillator implantation for secondary prevention at Copenhagen University Hospital, Rigshospitalet, and Hospital Clínic, University of Barcelona, of which n = 170 patients had a conventional (no LGE protocol) CMR and n = 60 patients had LGE‐CMR (including LGE protocol). Scar tissue including core, border zone (BZ) and BZ channels were automatically detected by specialized investigational software in patients with LGE‐CMR. The primary endpoint was recurrent VA. Results: After exclusion, n = 52 VA‐OHCA patients with LGE‐CMR and a mean left ventricular ejection fraction of 49 ± 16% were included, of which 18 (32%) patients reached the primary endpoint of VA. Patients with recurrent VA in exhibited greater scar mass, core mass, BZ mass, and presence of BZ channels compared with patients without recurrent VA. The presence of BZ channels identified patients with recurrent VA with 67% sensitivity and 85% specificity (area under the ROC curve (AUC) 0.76; 95% CI: 0.63–0.89; p <.001) and was the strongest predictor of the primary endpoint. Conclusions: The presence of BZ channels was the strongest predictor of recurrent VA in patients with an out of‐hospital cardiac arrest and LGE‐CMR. [ABSTRACT FROM AUTHOR]

Introduction: Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE‐CMR) imaging which may impact ventricular tachycardia (VT) management. Methods: The objective was to compare the findings of cardiomyopathy genetic testing on DE‐CMR imaging and long‐term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0‐3 mm, 3‐5 mm and >5 mm projected on the closest endocardial surface) was determined. Results: Forty‐three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring‐like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p =.001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p =.005), and increased VT recurrence (HR 5.7 95% CI[1.8‐18.4], p =.003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22‐18.0], p =.02). Conclusions: Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation. [ABSTRACT FROM AUTHOR]

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

Introduction: Reconnections to pulmonary vein (PV) triggers of atrial fibrillation (AF) are the primary cause of AF recurrence after PV isolation (PVI) with radiofrequency (RF) or cryoballoon catheter ablation (CRYO), but method‐specific contributions to PV reconduction pattern and conductive gap location are incompletely understood. Methods: The objective of this radiofrequency versus cryoballoon catheter ablation for paroxysmal atrial fibrillation substudy was to determine procedure‐specific patterns of PV reconduction in a randomized population with protocol‐mandated repeat procedures, irrespective of AF recurrence. Each PV was assessed in turn and PV reconnection sites were identified by high‐density electroanatomical mapping and locating the earliest activation site. Gap locations were verified by PV re‐isolation. Results: In 98 patients, 81% versus 76% previously isolated PVs remained isolated after CRYO versus RF (risk ratio [RR]: 1.06; 95% confidence interval [CI]: 0.96–1.18; p =.28). There were no significant differences for any PV: left superior PV: 90% versus 80%; left inferior PV: 80% versus 78%; right superior PV: 81% versus 80%, and right inferior PV: 76% versus 73%. For each reconnected PV, 34% of ipsilateral PVs were also reconnected after CRYO compared with 64% after RF (RR: 0.54; 95% CI: 0.32–0.90; p =.01). After RF, gaps were clustered by the carina and adjacent segments, whereas they were more heterogeneously distributed after CRYO. Conclusion: Although RF and CRYO produce similar proportions of durably isolated PVs, gap locations appear to develop in procedure‐specific patterns. After RF, ipsilateral PV reconduction is more frequent and gap sites cluster by the carina, suggesting that this region should be selectively ablated for more durable PVI. [ABSTRACT FROM AUTHOR]

Introduction: Electrical isolation of pulmonary veins (PVI) is a cornerstone for atrial fibrillation (AF) ablation. The overall effect of AF ablation, and especially lesions beyond PVI, on left atrial (LA) function is currently poorly understood. Our aim was to determine if LA function is different in patients after extensive LA ablation compared to PVI only. We performed non‐inferiority analysis of LA function after PVI with additional nonpulmonary vein ablation lesions in LA (PVI+) and PVI alone. Methods: We studied 68 patients consecutive patients who underwent AF ablation and who had complete transthoracic echocardiogram (TTE) within 12 months before AF ablation and 1−12 months after the procedure. Patients were stratified into two groups: PVI only and PVI+. Primary outcome was change in LA reservoir strain (LASr). Noninferiority margin was defined at 6%. Results: The PVI only group had a higher proportion of patients with paroxysmal AF (70% vs. 30%). The PVI+ group was observed to have a slightly higher increase in LASr compared to PVI alone (5.0% vs. 4.3%, p <.01 for noninferiority). LASr noninferiority was confirmed when adjusted for age, sex, coronary artery disease, hyperlipidemia, and AF type, rhythm at preprocedure TTE in a multivariable linear regression model, 90% CI (−5.46 to 2.04), p <.01. Conclusion: LA functional improvement evaluated by LASr was noninferior after PVI with additional LA ablation lesions compared to PVI alone. These findings were confirmed when adjusted for confounding clinical variables, suggesting that more extensive ablation does not negatively affect LA function. [ABSTRACT FROM AUTHOR]

Introduction: Physical techniques used for the prevention of vasovagal syncope have limited evidence for efficacy. We aimed to evaluate multimodal supervised physical training as a treatment approach. Methods: In this 1:1 randomized trial, patients with ≥2 episodes of clinically diagnosed vasovagal syncope were included. On top of standard care, the intervention arm performed supervised tilt training and aerobic exercise in six sessions at a cardiac rehabilitation center (three sessions during the first month, and then at 3‐month intervals), plus home tilt training. The control arm received standard care with a similar protocol of home tilt training. The primary outcome was time to first syncopal recurrence during 1 year of follow‐up. Results: Fifty participants were randomized (mean age: 34.5 ± 14.8 years; 64% female). The rate of syncopal recurrence was 28% and 64% within the intervention and control arms, respectively, with significantly higher syncope‐free survival at 1 year in the intervention arm (Log‐rank p =.003). The frequency of recurrent syncopal events was significantly lower with physical training (p =.017). Participants in the intervention arm reported significantly higher adherence to the home tilt training program (80% vs. 52%; p =.037). Conclusion: Among patients with recurrent vasovagal syncope, a supervised program of tilt training and aerobic exercise reduced syncopal recurrence. Future trials are warranted to further investigate multimodal supervised physical techniques as a therapeutic approach in treating vasovagal syncope. [ABSTRACT FROM AUTHOR]

Introduction: Left ventricular (LV) lead optimal positioning is one of the most important determinants of cardiac resynchronization therapy (CRT) success. LV quadripolar active fixation (QAF) leads have been designed to ensure stable LV pacing in the target area and reduce the likelihood of phrenic nerve stimulation (PNS). The aim of this analysis is to compare performances, safety, and clinical outcomes of QAF with those of quadripolar passive fixation leads (QPL) and bipolar active fixation (BAF) leads in a real‐world cohort of CRT patients. Methods and Results: This retrospective analysis compared the procedure and follow‐up data of 117 QAF included in the One Hospital ClinicalService project from nine Italian hospitals with two historical cohorts of 261 BAF and 124 QPL. QAF enabled basal pacing more frequently than QPL (24.1% vs. 6.5%, p <.001) but not differently from BAF (p =.981). At implant, mean QAF LV myocardial threshold (LVMT) was 1.21 ± 0.8 V at 0.4 ms, not different from that of BAF (p =.346) and QPL (p =.333). At a median follow‐up of 22 months, LVMT was 1.37 ± 0.90 V (p =.036 vs. implant). Acute LV lead dislodgment occurrence was low in all cohorts: 1 (0.9%) in QAF, 4 in BAF (1.5%), and none (0.0%) in QPL. During follow‐up, total LV‐related complication rate was lower in QAF (0.5/100 patient‐years) than in BAF (4.2/100 patient‐years, p =.014) and QPL (3.6/100 patient‐years, p =.055). QAF, BAF, and QPL annual rate of heart failure hospitalization were respectively 6.1/100 patient‐years, 2.5/100 patient‐years (p =.081), and 3.6/100 patient‐years (p =.346). CRT responders' rate in QAF was 69.9%, with no difference in comparison to BAF (p =.998) and QPL (p =.509). During follow‐up, mean left ventricular ejection fraction (LVEF) of QAF increased from 31.8 ± 10.1% to 40.3 ± 10.7% (p <.001). The average degree of echocardiographic response (ΔLVEF) did not differ between QAF and other cohorts; however, LVEF CRT responder's distribution of QAF differs from those of BAF (p =.003) and QPL (p =.022), due to a higher percentage of super‐responders. Conclusions: QAF with short interelectrode spacing resulted in non‐inferior clinical outcomes and CRT responders' rate in comparison to BAF and QPL, while reducing complication rate during follow‐up and increasing the possibilities of electronic repositioning to manage PNS or to optimize resynchronization therapy. [ABSTRACT FROM AUTHOR]

Introduction: Esophageal injury is rare but potentially a devastating complication of atrial fibrillation (AF) ablation. The goal here was to provide insight into the short‐term natural history of esophageal thermal injury (ETI) after radiofrequency catheter ablation (RFCA) for AFby esophagogastroduodenoscopy (EGD). Methods: We screened patients who underwent RFCA for AF and EGD based on esophageal late gadolinium enhancement (LGE) in postablation magnetic resonance imaging. Patients with ETI diagnosed with EGD were included. We defined severity of ETI according to Kansas City classification: type 1: erythema; type 2: ulcers (2a: superficial; 2b deep); type 3 perforation (3a: perforation; 3b: perforation with atrioesophageal fistula [AEF]). Repeated EGD was performed within 1−14 days after the last EGD if recommended and possible until any certain healing signs (visible reduction in size without deepening of ETI or complete resolution) were observed. Results: ETI was observed in 62 of 378 patients who underwent EGD after RFCA. Out of these 62 patients with ETI, 21% (13) were type 1, 50% (31) were type 2a and 29% (18) were type 2b at the initial EGD. All esophageal lesions, but one type 2b lesion that developed into an AEF, showed signs of healing in repeated EGD studies within 14 days after the procedure. The one type 2b lesion developing into an AEF showed an increase in size and ulcer deepening in repeat EGD 8 days after the procedure. Conclusion: We found that all ETI which did not progress to AEF presented healing signs within 14 days after the procedure and that worsening ETI might be an early signal for developing esophageal perforation. [ABSTRACT FROM AUTHOR]