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Late gadolinium enhanced cardiac magnetic resonance (LGE-CMR) imaging may help identify radiofrequency ablation lesions, which have been poorly described in patients with nonischemic cardiomyopathy (NICM).The purpose of this study was to describe LGE-CMR characteristics of ablation lesions in patients with NICM and correlate them with histopathology.Twenty-six patients (24 men; ejection fraction 38% ± 14%; age 61 ± 9 years) who had undergone CMR imaging after ventricular tachycardia (VT) ablation were included. Areas of both dark and bright core lesions correlating with previous radiofrequency ablation lesions were identified. Histology was performed on an explanted heart.Mean time between the ablation procedure and the LGE-CMR study was 8 [2-20] months. Twenty-three of 26 patients demonstrated dark core lesions (volume 2.16 ± 1.8 cmAblation lesions can be detected by LGE-CMR after VT ablation in NICM patients and have a different appearance than scar tissue. These lesions can be observed in the acute and chronic settings after ablations.

To investigate whether the current standard voltage cut-off of0.5 for dense scar definition on endocardial bipolar voltage mapping (EBVM), using a high-resolution multipoint mapping catheter with microelectrodes (HRMMC), correctly identifies the actual scar area described on CT with myocardial thinning (CT MT).Forty patients (39 men; 67.0 ± 9.0 y/o) with a history of transmural myocardial infarction (mean time interval since MI 15.0 ± 7.9 years) and sustained ventricular tachycardia (VT) were consecutively enrolled. A CT MT was performed in each patient before VT ablation. The CT MT 3D anatomical model, including MT layers, was merged with the 3D electroanatomical and EBVM. Different predefined cut-off settings for scar definition on EBVM were used to identify the optimal ones, which showed the best overlap in terms of scar area with the different MT layers.A cut-off value of0.2 mV demonstrated the best correlation in terms of scar area with the 2 mm thinning on CT MT (p = .04) and a cut-off of1 mV best overlapped with the 5 mm thinning (p = .003). The currently used0.5 mV cut-off for scar definition on EBVM proved to be the best area correlation with 3 mm thinning (p = .0002).In order to better identify the real extent of scar areas after transmural MI as described on preprocedural CT MT, higher cut-off values for scar definition should be applied if the EBVM is performed using a HRMMC.

Introduction Cardioneuroablation (CNA) is a technique used to modulate cardiac parasympathetic tone in patients with sino-atrial (SA) and atrio-ventricular (AV) vagally mediated syncope. We describe the case of a patient who developed AV block after a first procedure of CNA, requiring a second procedure. Case presentation A 47-Year-old man presented with recurrent syncope (daily episodes) associated with high vagal tone conditions. An ECG monitoring showed frequent episodes of sinus bradycardia and sinus arrest, with pauses up to 17 seconds. AV node conduction impairment was never identified. A CNA procedure targeting the right superior and posterior ganglionated plexi (GPs), both from the left and right atrium, was performed with acute success. The subsequent night, repetitive episodes of AV block with normal sinus rate were observed. A second procedure was performed targeting the posteromedial left GP. Follow-up at 4 months showed no recurrent syncopal event and no bradyarrhythmia episode on the implantable loop recorder. Conclusion This case report demonstrates that ablation limited to the right superior and posterior GPs may not be enough for neurocardiogenic syncope and a more systematic approach, extending the ablation to the posteromedial left GP, should be considered.

Catheter ablation has brought major advances in the management of patients with atrial fibrillation (AF). As evidenced by multiple randomized trials, AF catheter ablation can reduce the risk of recurrent AF and improve quality of life. In some studies, AF ablation significantly reduced cardiovascular hospitalizations. Despite the existing data on AF catheter ablation, numerous knowledge gaps remain concerning this intervention. This report is based on a recent virtual workshop convened by the National Heart, Lung, and Blood Institute to identify key research opportunities in AF ablation. We outline knowledge gaps related to emerging technologies, the relationship between cardiac structure and function and the success of AF ablation in patient subgroups in whom clinical benefit from ablation varies, and potential platforms to advance clinical research in this area. This report also considers the potential value and challenges of a sham ablation randomized trial. Prioritized research opportunities are identified and highlighted to empower relevant stakeholders to collaborate in designing and conducting effective, cost-efficient, and transformative research to optimize the use and outcomes of AF ablation.

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The healthcare sector accounts for nearly 5% of global greenhouse gas emissions (GHG) and is a significant contributor to complex waste. Reducing the environmental impact of technology-heavy medical fields such as cardiac electrophysiology (EP) is a priority. The aim of this survey was to investigate the practice and expectations in European centres on EP catheters environmental sustainability. A 24-item online questionnaire on EP catheters sustainability was disseminated by the EHRA Scientific Initiatives Committee in collaboration with the Lyric Institute. A total of 278 physicians from 42 centres were polled; 62% were motivated to reduce the environmental impact of EP procedures. It was reported that 50% of mapping catheters and 53% of ablation catheters are usually discarded to medical waste, and only 20% and 14% of mapping and ablation catheters re-used. Yet, re-use of catheters was the most commonly cited potential sustainability solution (60% and 57% of physicians for mapping and ablation catheters, respectively). The majority of 69% currently discarded packaging. Reduced (42%) and reusable (39%) packaging also featured prominently as potential sustainable solutions. Lack of engagement from host institutions was the most commonly cited barrier to sustainable practices (59%). Complexity of the process and challenges to behavioral change were other commonly cited barriers (48% and 47%, respectively). The most commonly cited solutions towards more sustainable practices were regulatory changes (31%), education (19%), and product after-use recommendations (19%). In conclusion, EP physicians demonstrate high motivation towards sustainable practices. However, significant engagement and behavioural change, at local institution, regulatory and industry level is required before sustainable practices can be embedded into routine care.

Introduction: Atrial fibrillation (AF) is the most common arrhythmia and is associated with deleterious remodelling processes. In AF patients, the plasmatic succinate content increases, indicating a potential role for metabolic remodelling in AF progression. Objective: To assess the impact of succinate on the electrophysiological properties of right atria (RA) in a persistent AF sheep model. Methods: Optical mapping experiments were performed in ex vivo RA from a burst pacing AF sheep model (SHAM=5; AF=5). The right coronary artery was perfused with Tyrode solution initially containing glucose (5.6mM), subsequently replaced by succinate (5mM). Action potential durations at 80% of repolarization (APD80) and mean conduction velocities (CV) were assessed from 2 to 5Hz pacing frequency and during sinus rhythm (SR). An S1S2 protocol was used to determine effective refractory period (ERP) and a burst pacing procotol (20Hz) to assess ex vivo AF vulnerability. Finally, an organ donation program allowed us to investigate these properties in a human RA from an AF patient. Results: SR frequency was higher in AF than SHAM sheep (2.0 vs. 1.6 Hz; p=0.19). Succinate perfusion decreased SR frequency by 18% in SHAM sheep (1.7 vs. 1.4 Hz; p=0.12) and by 43% in AF sheep (2.0 vs. 1.2 Hz; p=0.009). The ERP was lower in AF than SHAM sheep (184 vs. 210 ms; p=0.5) and succinate induced a significant increase of 136% in SHAM sheep (210 vs. 286 ms; p=0.06) and of 188% in AF sheep (184 vs. 346 ms; p=0.0008). Epicardial APD80 was lower when pacing at 2.5Hz in AF than SHAM sheep (165 vs. 197 ms ; p=0.3). Succinate increased APD80 in both SHAM and AF RA (191 to 224 ms; 165 to 231 ms) but its effect was more important in AF than SHAM sheep (148 vs. 117 %; p=0.1). Mean CV was slower in AF sheep than SHAM sheep (110 vs. 130 cm/s; p=0.47). Succinate slowed mean CV on AF sheep (110 vs. 76; p=0.4) but did not affect SHAM RA. In the human RA, APD80 (257 vs; 309 ms) and total activation time were increased by succinate. Conclusions: Our results indicate that succinate alters atrial electrophysiological properties, most likely through the associated ROS overproduction. Importantly, AF sheep showed an increased sensitivity to succinate perfusion. Preliminary data in a human RA are in line with these observations.

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging distinguishes between intrinsic postinfarction scar and radiofrequency ablation lesion related scar (dark core lesions [DCLs]) in patients with prior ventricular tachycardia (VT) ablation procedures.To combine LGE-CMR and electroanatomic mapping data to describe the relationship between DCLs and recurrent VT among patients undergoing repeat ablations for postinfarction VT.Consecutive patients with repeat ablation for postinfarct VT with LGE-CMR before the repeat procedures were studied. Prior ablation procedures and implantable cardiac defibrillator electrograms were analyzed to determine new versus previously documented VT. DCLs were identified on preprocedure LGE-CMR and registered to electroanatomic maps. A control group of patients undergoing repeat ablation procedures without imaging was included.Nineteen study patients and 14 control patients were followed for 2.6 (1.6-5.6) years (31 [94%] men, age 65.8 ± 8.4 years, ejection fraction 24.7 ± 10.3, p 0.10 for all). DCLs corresponded to unexcitable tissue during repeat procedures (area 22.4 ± 15.1 vs. 22.9 ± 16.8 cmLGE-MRI can identify prior ablation lesions corresponding to nonexcitable tissue during repeat ablation procedures for postinfarction VT. VT target sites are often located in close proximity to the DCL area that may function as a fixed border for reentry circuits. Registration of DCL from prior ablation may facilitate repeat ablation procedures.

Aims Mapping data of human ventricular fibrillation (VF) are limited. We performed detailed mapping of the activities underlying the onset of VF and targeted ablation in patients with structural cardiac abnormalities. Methods and results We evaluated 54 patients (50 ± 16 years) with VF in the setting of ischaemic (n = 15), hypertrophic (n = 8) or dilated cardiomyopathy (n = 12), or Brugada syndrome (n = 19). Ventricular fibrillation was mapped using body-surface mapping to identify driver (reentrant and focal) areas and invasive Purkinje mapping. Purkinje drivers were defined as Purkinje activities faster than the local ventricular rate. Structural substrate was delineated by electrogram criteria and by imaging. Catheter ablation was performed in 41 patients with recurrent VF. Sixty-one episodes of spontaneous (n = 10) or induced (n = 51) VF were mapped. Ventricular fibrillation was organized for the initial 5.0 ± 3.4 s, exhibiting large wavefronts with similar cycle lengths (CLs) across both ventricles (197 ± 23 vs. 196 ± 22 ms, P = 0.9). Most drivers (81%) originated from areas associated with the structural substrate. The Purkinje system was implicated as a trigger or driver in 43% of patients with cardiomyopathy. The transition to disorganized VF was associated with the acceleration of initial reentrant activities (CL shortening from 187 ± 17 to 175 ± 20 ms, P Conclusions The onset of human VF is sustained by activities originating from Purkinje and structural substrate, before spreading throughout the ventricles to establish disorganized VF. Targeted ablation results in effective reduction of VF burden. Key question The initial phase of human ventricular fibrillation (VF) is critical as it involves the primary activities leading to sustained VF and arrhythmic sudden death. The origin of such activities is unknown. Key finding Body-surface mapping shows that most drivers (≈80%) during the initial VF phase originate from electrophysiologically defined structural substrates. Repetitive Purkinje activities can be elicited by programmed stimulation and are implicated as drivers in 37% of cardiomyopathy patients. Take-home message The onset of human VF is mostly associated with activities from the Purkinje network and structural substrate, before spreading throughout the ventricles to establish sustained VF. Targeted ablation reduces or eliminates VF recurrence.

Transient Atrial-His Block during Wide QRS-Complex Tachycardia with 1:1 Ventriculoatrial Relationship: What is the Diagnosis?

This study sought to determine whether durable pulmonary vein isolation (PVI) using pulsed field ablation (PFA) translates to freedom from atrial fibrillation recurrence without an increase in adverse events.PFA is a nonthermal ablative modality that, in preclinical studies, is able to preferentially ablate myocardial tissue with minimal effect on surrounding tissues. Herein, we present 1-year clinical outcomes of PFA.In 3 multicenter studies (IMPULSE [A Safety and Feasibility Study of the IOWA Approach Endocardial Ablation System to Treat Atrial Fibrillation], PEFCAT [A Safety and Feasibility Study of the FARAPULSE Endocardial Ablation System to Treat Paroxysmal Atrial Fibrillation], and PEFCAT II [Expanded Safety and Feasibility Study of the FARAPULSE Endocardial Multi Ablation System to Treat Paroxysmal Atrial Fibrillation]), paroxysmal atrial fibrillation patients underwent PVI using a basket or flower PFA catheter. Invasive remapping was performed at ∼2 to 3 months, and reconnected PVs were reisolated with PFA or radiofrequency ablation. After a 90-day blanking period, arrhythmia recurrence was assessed over 1-year follow-up.In 121 patients, acute PVI was achieved in 100% of PVs with PFA alone. PV remapping, performed in 110 patients at 93.0 ± 30.1 days, demonstrated durable PVI in 84.8% of PVs (64.5% of patients), and 96.0% of PVs (84.1% of patients) treated with the optimized biphasic energy PFA waveform. Primary adverse events occurred in 2.5% of patients (2 pericardial effusions or tamponade, 1 hematoma); in addition, there was 1 transient ischemic attack. The 1-year Kaplan-Meier estimates for freedom from any atrial arrhythmia for the entire cohort and for the optimized biphasic energy PFA waveform cohort were 78.5 ± 3.8% and 84.5 ± 5.4%, respectively.PVI with a "single-shot" PFA catheter results in excellent PVI durability and acceptable safety with a low 1-year rate of atrial arrhythmia recurrence. These data mitigate concern that the nonthermal ablative mechanism of PFA might mask undiscovered compromises to clinical success. (IMPULSE: A Safety and Feasibility Study of the IOWA Approach Endocardial Ablation System to Treat Atrial Fibrillation, NCT03700385; A Safety and Feasibility Study of the FARAPULSE Endocardial Ablation System to Treat Paroxysmal Atrial Fibrillation, NCT03714178; PEFCAT II Expanded Safety and Feasibility Study of the FARAPULSE Endocardial Multi Ablation System to Treat Paroxysmal Atrial Fibrillation [PEFCAT II], NCT04170608).

Persistent left superior vena cava (LSVC) is the most common thoracic venous anomaly. It is frequently implicated in atrial fibrillation initiation and maintenance in patients who harbor them, as exemplified by this case study. The LSVC is in continuity with the CS and can be disconnected from the left atrium to which it is connected by multiple myocardial bridges, creating an ideal substrate for rapid reentry.

We present a 40-year old patient with symptomatic persistent AF. This case illustrates the importance of thoracic veins in the pathogenesis of atrial fibrillation. In this case, PV isolation resulted in a drastic cycle length prolongation with AF persisting with periods of organized activation sequence allowing for localization of the culprit area: a bursting SVC, whose isolation led to sinus resumption.