BACKGROUND:In the presence of sustained monomorphic ventricular tachycardia (VT), catheter ablation may be an option in congenital heart disease. However, the heterogeneity of underlying congenital heart disease and previous cardiac surgeries is associated with a unique and particularly complex substrate. The aim of the study was to investigate whether preprocedural 3-dimensional anatomic and substrate reconstruction based on cardiac computed tomography scan or magnetic resonance imaging could reliably identify VT substrate and ablation targets. METHODS:Consecutive patients with cardiac computed tomography or magnetic resonance imaging referred for VT ablation in 5 congenital electrophysiology centers were included. Three observers, electrophysiologists, blinded to the ablation procedure and each other, annotated potential ablation targets on 3-dimensional imaging reconstructions with a dedicated software (InHeart). Once completed, the annotations were compared between observers and with the ablation target(s) on the electroanatomical mapping generated during the procedures. RESULTS:Forty patients (mean age, 38±12 years; 67.5% male) underwent VT ablation, including 28 with a history of spontaneous sustained VT. VT was inducible in 97.5% of cases, with an acute success rate of ablation of 92.5%. Preprocedural imaging identified VT substrate in concordance with electroanatomical mapping in 87.5% of cases. There was a high degree of agreement between the observers. Positive interobserver agreement was complete in 65.0% of cases, moderate in 22.5%, and poor in 5.0%. Considering the total number of isthmuses identified by imaging in comparison with electroanatomical mapping, the sensitivity of imaging was 87.0%, and its positive predictive value was 77.0%. CONCLUSIONS:In our series, 3-dimensional anatomic reconstruction enabled identification of the critical VT substrate in most patients with complex congenital heart disease, particularly those with anatomically based reentrant circuits. Substrate target can be identified by operators with good interobserver reproducibility. This approach may guide VT ablation in these challenging cases.

BACKGROUND:We assessed the electro-anatomic mapping (EAM) capabilities of a pulsed field ablation (PFA) system previously guided by fluoroscopy to assess acquisition modes, and effects of near and far-field signal. METHODS:After pulmonary vein isolation (PVI) proven by pacing to check entrance and exit block, EAM was performed in 2 modes with the Faraview system during CS pacing. Mode 1 utilized bipoles between electrode 3 of each adjacent catheter spline. Mode 2 utilized a pseudo-unipole between electrode 3 and a combination of electrodes 1, 2, and 4 on individual splines. Signals and voltage map demonstration of PVI were compared with pacing assessment. Two observers assessed the maps with a third observer to resolve discrepancies. RESULTS:Fifteen patients (87% male, aged 58 ± 9 years) had PVI then mapping with the Faraview system. Pacing confirmed isolation of all pulmonary veins. Bipolar mapping (mode 1) displayed multiple apparent PV signals: only 32/61 (52%) of veins appeared isolated. On pseudo-unipolar mapping 59/61 (97%) of veins appeared isolated. The majority of variance in assessment (70.4%) was explainable by the mapping method with minimal variance attributed to observer. CONCLUSIONS:Pseudo-unipolar EAM Faraview mode appears the most accurate for assessment post-PVI compared with bipolar mode.

BACKGROUND:Peritricuspid, or cavotricuspid isthmus-dependent, atrial flutter is the most common arrhythmia in patients with dextro-transposition of the great arteries treated with atrial switch surgery, but its underlying mechanisms remain poorly understood. METHODS:Twenty consecutive patients with prior atrial switch surgery referred for atrial flutter ablation were included. All underwent transbaffle puncture and high-density mapping. Anatomic barriers, activation patterns, conduction velocities, and low-voltage areas were assessed. RESULTS:In all cases of peritricuspid atrial flutter, surgical incisions defined the posterior boundary of the circuit. The narrowest segment of the reentry was consistently located within a septal corridor bounded posteriorly by the baffle incision and anteriorly by the tricuspid annulus. Slow conduction (<30 cm/s) was identified in this septal corridor in 92% of peritricuspid flutters and in 85% of patients during sinus or paced rhythm. Low-voltage areas were limited and frequently colocalized with regions of slow conduction. No patient exhibited slow conduction or low voltage at the cavotricuspid isthmus. The septal corridor was also involved in 60% of nonperitricuspid reentrant atrial tachycardias. Programmed atrial stimulation with S2 mapping accentuated conduction delay in this region, with demonstration of functional block and induction of atrial flutter. CONCLUSIONS:In patients with dextro-transposition of the great arteries corrected by atrial switch, surgical incisions define posterior boundaries and create a narrow septal corridor, or baffle-tricuspid isthmus, characterized by slow conduction and a propensity for functional block. These anatomic and electrophysiological features likely underlie the high prevalence of peritricuspid reentry in this population, representing a ubiquitous critical substrate for arrhythmia initiation and maintenance. Systematic cavotricuspid isthmus ablation should, therefore, be considered in these patients.

BACKGROUND:Outcomes after ventricular tachycardia (VT) ablation in patients with a septal substrate are poor. OBJECTIVE:This study aimed to evaluate a strategy for septal VT ablation combining substrate imaging and a large-footprint dual-energy catheter. METHODS:Patients presenting with drug-refractory VT in the setting of a predominantly septal substrate identified on preoperative imaging were prospectively included. Ablation targets were identified through a combination of imaging-based substrate identification and conventional endocardial mapping data. They were targeted using a large-footprint dual-energy catheter. RESULTS:12 procedures were performed in 10 consecutive patients. 9 of them had at least 1 previous failed ablation procedure, including nonstandard radiofrequency (RF) ablation strategies in 5. 6 of them were in a VT storm at the time of ablation. Substrate imaging using a computed tomography scan with late iodine acquisition showed intramural septal substrate in all. Noninducibility was reached in 83% of the procedures. 60% remained free from VT after the last procedure with a mean follow-up time of 9.9 ± 2.2 months. The ablation protocol was adapted during the study. In the last 5 patients, where the final optimized ablation protocol was used combining pulsed field and RF energy, 80% remained free from VT. CONCLUSION:Septal VT ablation using a strategy combining substrate imaging and large-footprint dual-energy lattice-tip catheter leads to a high rate of noninducibility and good outcomes during short-term follow-up, especially when combining RF and pulsed field energy.

AIM:Sudden cardiac death occurs mainly outside of the hospital, placing witnesses in a pivotal role to intervene and enhance the survival. We aim to investigate its potential psychological repercussions on both the patient and the witness. OUTCOMES:Incidence of acute stress disorder and/or post-traumatic stress disorder among patients and their relatives at 3 and 6 months following sudden cardiac death. METHODS:All patients admitted for resuscitated sudden cardiac death at our institution between 2019 to 2021 were screened. Within 15 days following resuscitated sudden cardiac death, both the patients and one of their relatives underwent face-to-face interviews with dedicated questionnaires. At 3-6 months post-event, participants were contacted by phone to complete the questionnaires. RESULTS:Twenty-two patients (6 females, 51±11yo) and 23 relatives (13 females, 49±15yo) were included. The reason for sudden cardiac death was ischemic (n=9/22) or dilated cardiomyopathies (n=5/22), idiopathic ventricular fibrillation (n=4/22) or others (4/22). Relatives exhibited a higher magnitude of acute stress compared to patients (26±25 vs 48±20, P<0.001). Five persons were lost to follow-up (2 patients and 3 relatives). Nevertheless, 4/20 (20%) patients and 3/20 (15%) relatives were diagnosed with post-traumatic stress disorder. CONCLUSIONS:Post-traumatic stress disorder in patients/relatives is frequent after resuscitated sudden cardiac death (20 to 15%). It is crucial to maintain close vigilance since patients remain susceptible to the future onset of post-traumatic stress disorder, even when they manifest milder symptoms of acute stress. Offering early interventions for relatives may serve as a preventive measure.

Pharmacological and electrical cardioversion of atrial fibrillation (AF) is associated with markedly increased (>10-fold) risk of thromboembolic events clustering within 7 days following sinus rhythm restoration. Current evidence indicates that post-cardioversion thrombus formation from atrial stunning, rather than preexisting thrombus, causes most thromboembolic complications. Risk factors include traditional CHA2DS2-VASc components (particularly heart failure), AF duration ≥12h, mitral valve stenosis, cardiac amyloidosis and hypertrophic cardiomyopathy. While placebo-controlled randomized trials are lacking, there is overwhelming observational evidence that oral anticoagulation (OAC) reduces post-cardioversion thromboembolism by 60-80% to a residual risk of approximately 0.5%. This benefit seems independent of CHA2DS2-VASc and AF duration (including <48h). Current guidelines recommend OAC for ≥3 weeks before and ≥4 weeks after cardioversion, or to rule out intracardiac thrombus by imaging, with OAC immediately before cardioversion and for ≥4 weeks. The safety of this strategy was validated in large prospective trials. However, alternative durations of pre-/post-cardioversion OAC have never been tested in randomized trials. The optimal duration of pre-cardioversion OAC remains unclear. Shorter pre-cardioversion delay is associated with increased success of cardioversion, reduced AF recurrence, reduced severity and duration of atrial stunning, and possibly reduced thromboembolic complications. Likewise, antiarrhythmic drug (AAD) pre-treatment improves cardioversion outcomes but is sometimes withheld by fear of early sinus rhythm restoration and associated thromboembolic risk. Randomized data from the ACUTE trial have shown that early AAD introduction was safe. Given the short-lived but dramatic increase in thromboembolic risk post-cardioversion, intensifying OAC immediately before cardioversion might further reduce risk, as suggested by observational studies.

BACKGROUND:Vein of Marshall ethanol infusion (VOMEI) has benefit in patients with persistent atrial fibrillation and perimitral atrial flutter, whereas coronary sinus (CS) radiofrequency ablation (RFA) improves mitral isthmus block. Atrial arrhythmias frequently coexist with left ventricular (LV) systolic dysfunction, for which cardiac resynchronization therapy (CRT) may be indicated. OBJECTIVE:This study aimed to evaluate the safety, feasibility, and outcomes of VOMEI ± CS RFA in patients with CRT METHOD: Coding data were used to identify consecutive patients with CRT who underwent VOMEI ± CS RFA at 2 centers. Controls without CRT who underwent contemporaneous VOMEI ± CS RFA provided comparison. Clinical and procedural characteristics and recurrence within 12 months were recorded for all patients. Lead parameters were compared before and after ablation in patients with CRT, and any lead dysfunction over 43 ± 21 months of follow-up was recorded. RESULTS:VOMEI was feasible in 94% (94% CRT vs 97% control; P = .92), and CS RFA in 89% (84% vs 93%; P = .71). Complications occurred in 5% (6% vs 3%; P = .54), precluding successful VOMEI without causing patient morbidity. No difference in the need for alternative fluoroscopic projections, balloon-occlusion venography, or mitral isthmus block achievement was seen. No significant change in LV lead parameters was observed, and only 1 case of lead dysfunction was seen (phrenic capture, 2%). Arrhythmia recurrence within 1 year was 42% vs 24% CONCLUSION: VOMEI and CS RFA are feasible and safe in patients with LV leads. Complications are uncommon and preclude VOMEI without causing patient morbidity when they occur, and the risk of clinically significant lead dysfunction is low.

BACKGROUND:Beyond pulmonary veins isolation (PVI), the ablation strategy that has prevailed over the past two decades remains controversial: (1) the left atrium partition using linear lesions ("cox-maze" strategy); (2) the mapping of the left atrium in atrial fibrillation (AF) to identify and localize the arrhythmia sources. Both methods have failed to demonstrate superiority compared to PVI alone. Whether the addition of a systematic vein of Marshall (VOM) ethanol infusion and empirical linear ablation to PVI (Marshall-Plan) improves outcomes in patients with persistent AF remains to be demonstrated. OBJECTIVES:To compare the 2-year freedom from any atrial arrhythmia (atrial fibrillation [AF]/atrial tachycardia [AT]) between the Marshall-Plan approach and the PVI approach in patients with persistent AF. METHODS:The Marshall Plan is a multicenter, prospective, randomized, parallel- group, controlled clinical trial of superiority conducted in nine tertiary care centers across Europe (8 centers in France, 1 center in Belgium). A total of 262 patients will be randomized in two arms: Marshall-Plan, consisting of PVI with additional ablation, including vein of Marshall ethanol infusion, and lines of block at the mitral, dome, and cavotricuspid isthmuses versus PVI alone. The main outcome will be the 2-year freedom from any arrhythmia AF/AT <30 seconds) after a single ablation procedure with or without antiarrhythmic medication. CONCLUSIONS:This randomized trial aims to determine the success and safety of adjunctive VOM ethanol infusion and linear ablation to PVI in patients with persistent AF. REGISTRATION:URL: https://www. CLINICALTRIALS:gov; Unique identifier: NCT04681872.

The vein of Marshall (VOM) is a patent segment of the left cardinal vein that shrinks during embryologic development. The VOM runs along the lateral ridge of the left atrium, between the left pulmonary veins and the left atrial appendage, where it colocalizes with fat, intrinsic nerves, and a vestigial epicardial musculature named the Marshall bundle (MB). Ectopic beats can originate from the MB and trigger atrial fibrillation (AF) under sympathetic input. It has also been shown that high-frequency stimulation of the parasympathetic intrinsic nerves near the VOM induces AF. Because fat-insulating properties strongly protect the MB against electric energy, it frequently supports epicardial gaps during mitral line ablation. The VOM is a true atrial vein that can be safely used as a vascular route for retrograde chemical ablation of these structures implicated in the AF process and mitral isthmus gaps. Recent randomized studies show that VOM ethanol infusion improves sinus rhythm maintenance in patients with persistent AF, all the more if combined with mitral line block, which it greatly facilitates. Beyond pulmonary vein isolation, anatomical atrial transection conditioned by successful VOM ethanol infusion seems a promising strategy for persistent AF ablation.

BACKGROUND:Hemolysis was recently identified as a side effect of pulsed field ablation (PFA), which raised renal safety concerns. Further systemic effects of PFA-induced hemolysis remain unknown. OBJECTIVE:This study aimed to investigate the thromboinflammatory potential of PFA and the systemic biological effects of PFA-induced hemolysis. METHODS:We prospectively included 60 patients with paroxysmal atrial fibrillation receiving pulmonary vein isolation using a pentaspline PFA system (n = 30) or radiofrequency ablation (RFA) (n = 30). Biomarkers of inflammation, platelet activation, endothelial cell damage, hemolysis, and renal function were analyzed at 3 timepoints. Pericarditis, early recurrences, and 6-month rhythm outcomes were further assessed. RESULTS:Intravascular hemolysis was detected in 100% of PFA-treated patients after a mean of 42.8 ± 3.7 deliveries. Leukocyte release (Δ3.0 ± 2.3 vs 3.6 ± 2.3 × 109/L; P = .254), acute platelet activation, and endothelial cell damage biomarker changes were similar between PFA and RFA. Nitric oxide levels decreased significantly in the PFA group only (-26.5% ± 17.8%; P < .001). Although no acute kidney injury occurred, hemolysis burden was significantly associated with creatinine increase, inflammation, and platelet activation. Female sex was the only independent predictor of significant hemolysis after PFA (odds ratio, 7.8; 95% confidence interval, 1.2-50.2; P = .031). In-hospital pericarditis was lower with PFA (10.0% vs 33.3%; P = .028), whereas early (20.0% vs 26.7%) and late recurrences (6.7% vs 10.0%; all P > .05) were similar between groups. CONCLUSION:PFA is associated with a similar thromboinflammatory reaction as RFA. PFA-induced hemolysis occurs in all patients and is significantly associated with renal function decline, inflammation, and platelet activation even with limited PFA deliveries. Females are at a higher risk of significant hemolysis after PFA.

Electrical storm (ES) with refractory cardiogenic shock carries high mortality. While veno-arterial extracorporeal membrane oxygenation (V-A ECMO) may stabilize circulation, the role and timing of ventricular arrhythmia (VA) ablation under ECMO remain unclear. To assess the impact and optimal timing of VA ablation on ECMO weaning success in patients supported with V-A ECMO for ES-related refractory cardiogenic shock. We conducted a French multicenter retrospective cohort study including 218 patients treated between 2015 and 2023 in 9 tertiary centers. Patients requiring V-A ECMO for ES-related cardiogenic shock were included; 115 underwent VA ablation, and 103 did not. The primary endpoint was successful ECMO weaning, defined as liberation from ECMO alive without transition to durable mechanical circulatory support or heart transplantation 28 days after ECMO liberation. Analyses combined propensity-score matching, time-dependent Cox models, spline-based analysis, and landmark Fine Gray competing-risk analyses to account for immortal time and competing events. VA ablation was associated with higher ECMO weaning success (cs-HR 1.72, 95

BACKGROUND AND AIMS:Catheter ablation is performed in patients with recurrent ventricular tachycardia (VT) but remains complex and limited to experienced centres. Ventricular tachycardia ablation guided by pre-procedural imaging was shown promising in non-randomized trials. InEurHeart aims to evaluate computed tomography (CT)-guided VT ablation vs conventional ablation in a multicentre randomized controlled trial. METHODS:In 14 European centres, 113 patients with prior myocardial infarction and clinically significant VT were randomly assigned to CT-guided (n = 57) or conventional (n = 56) VT ablation. The primary objective was to demonstrate reduced procedural duration when using CT guidance. Secondary endpoints included efficacy (incidence and burden of ventricular arrhythmia), safety, as well as composite endpoints. RESULTS:The primary endpoint showed a significant decrease in procedure time favouring CT-guided ablation: 149 ± 51 to 120 ± 50 min, -19% [95% confidence interval (CI) -32; -7]; P = .0027 in intention to treat, and 149 ± 51 to 107 ± 38 min, -28% (95% CI -40; -16); P < .0001 per protocol. Major adverse events occurred in two (3.5%) in the conventional group vs one (1.8%) in the CT-guided group [-1.8% (95% CI -7.9; 4.3)]. Ventricular tachycardia-free survival at 1 year was achieved in 37 (67.3%) patients for conventional vs 43 (76.8%) for CT-guided VT ablation [9.5% (95% CI -10.4; 29.4), P = NS]. Ventricular tachycardia burden was decreased by 90% in the CT-guided group. CONCLUSIONS:In patients with ischaemic cardiomyopathy, CT-guided VT ablation reduces the procedure duration while maintaining a favourable efficacy and safety profile when compared with VT ablation without image integration.

BACKGROUND:Cardioneuroablation (CNA) targets the ganglionated plexus (GP) to treat neurally mediated syncope, yet a standardized GP identification method is lacking. Postprocessing of cardiac computed tomography (CT) data identifies epicardial fat, thus allowing fat pad identification. Whereas the feasibility of CT-guided CNA is documented, data about GP anatomy and comprehensive evaluations of GP targeting methods remain scarce. OBJECTIVE:This study sought to describe GP anatomy using CT fat pad segmentation and to evaluate the accuracy of different approaches in locating these GPs. METHODS:The study included 26 CNA or atrial fibrillation ablation patients. GPs were identified through CT-based fat segmentation. CT-derived atrial meshes were merged with corresponding meshes from electroanatomic mapping. Spatial correlation was studied between atrial fractionated electrograms (FEGMs) and epicardial fat pads. Several target areas from the different ablation approaches (FEGM, anatomic, CT-based fat pad identification, and target line) were spatially compared. RESULTS:Correlation between epicardial fat pads and signal fragmentation was weak in the left atrium (ρ = 0.01 ± 0.13 [P = .73]; ϕ = -0.00 ± 0.10 [P = .94]) and even negative in the right atrium (ρ = 0.11 ± 0.09 [P < .001]; ϕ = -0.10 ± 0.08 [P < .001]). The FEGM approach was associated with a more extensive ablation area (3.74% vs 17.0% [P < .001] for the anatomic and the FEGM approach for the left atrium and 3.45% vs 9.53% [P < .001] for the anatomic and the FEGM approach for the right atrium). CONCLUSION:CT-based fat pad segmentation reveals significant interpatient variability in GP anatomy. GPs show low colocalization with signal fragmentation, causing inaccurate localization based on fragmentation alone. An anatomy-focused approach offers a more targeted ablation strategy.

BACKGROUND:Although differential pacing (DP) has been conventionally used to confirm the achievement of block across linear lesion sets, high-resolution mapping (HRM)can unmask pseudoblock and persistent residual conduction across the lines. OBJECTIVES:This study aimed to compare conventional DP criteria with HRM for line assessment and to evaluate the impact of persistent residual conduction across a line on the risk of developing atrial tachycardia (AT) during follow-up. METHODS:Our study included consecutive patients who underwent AT or persistent atrial fibrillation ablation with ≥1 atrial linear lesion. We systematically evaluated the existence of a residual conduction through all linear lesions using HRM and compared this strategy with the results of DP. RESULTS:In a cohort of 102 patients, 101 cavotricuspid isthmus lines, 85 roof lines, and 84 mitral isthmus lines were systematically evaluated using DP and HRM. Among the cavotricuspid isthmus lines, 38 lines (37.6%) exhibited residual conduction as determined by HRM. In these 38 cases, DP yielded a false-positive result in 14 cases (37%). For the roof lines, 40 lines (47.1%) showed residual conduction, with DP yielding false-positive results in 16 (40%) of these cases. Regarding the mitral isthmus lines, 24 lines (28.6%) displayed residual conduction, and DP provided false-positive results in 13 (54%) of these cases. The 1-year AT-free survival rate was 95.4% in patients where all attempted lines were successfully blocked, compared to 31.9% in those with ≥1 line that remained unblocked despite multiple ablation attempts. CONCLUSIONS:The systematic use of HRM for line assessment allows to unmask a substantial proportion of pseudoblocks not identified by DP. The existence of a persistent residual conduction through a line is associated with a high risk of AT during follow-up.