Gaps after linear ablation of persistent atrial fibrillation (Marshall-PLAN): Clinical implication.

Background: Beyond pulmonary vein (PV) isolation, anatomic isthmus transection is an adjunctive strategy for persistent atrial fibrillation. Data on the durability of multiple lines of block remain scarce.

Objective: The purpose of this study was to evaluate the impact of gaps within such a lesion set.

Distribution of atrial low voltage induced by vein of Marshall ethanol infusion.

Introduction: Systematic and quantitative descriptions of vein of Marshall (VOM)-induced tissue ablation are lacking. We sought to characterize the distribution of low voltage observed in the left atrium (LA) after VOM ethanol infusion.

Methods And Results: The distribution of ethanol-induced low voltage was evaluated by comparing high-density maps performed before and after VOM ethanol infusion in 114 patients referred for atrial fibrillation ablation.

Sinus node exit, crista terminalis conduction, interatrial connection, and wavefront collision: Key features of human atrial activation in sinus rhythm.

Background: An understanding of normal atrial activation during sinus rhythm can inform catheter ablation strategies to avoid deleterious impacts of ablation lesions on atrial conduction and mechanics.

Objective: The purpose of this study was to describe how the sinus node impulse originates, propagates, and collides in right and left atria with normal voltage.

Methods: Fifty consecutive patients undergoing catheter ablation of atrial fibrillation with endocardial atrial voltage >0.

Effect of electrode size and spacing on electrograms: Optimized electrode configuration for near-field electrogram characterization.

Background: Detailed effects of electrode size on electrograms (EGMs) have not been systematically examined.

Objectives: We aimed to elucidate the effect of electrode size on EGMs and investigate an optimal configuration of electrode size and interelectrode spacing for gap detection and far-field reduction.

Methods: This study included 8 sheep in which probes with different electrode size and interelectrode spacing were epicardially placed on healthy, fatty, and lesion tissues for measurements.

Characterization of atrial fibrillation in real-world patients: testing the 4S-AF scheme in the Spanish and French cohorts of the EORP-AF Long-Term General Registry.

Aims: The 4S-AF scheme [Stroke risk, Symptom severity, Severity of atrial fibrillation (AF) burden, Substrate severity] has recently been described as a novel approach to in-depth characterization of AF. We aim to determine if the 4S-AF scheme would be useful for AF characterization and provides prognostic information in real-world AF patients.

Methods And Results: The Spanish and French cohorts of the EORP-AF Long-Term General Registry were included.

Vein of Marshall Ethanol Infusion: Feasibility, Pitfalls, and Complications in Over 700 Patients.

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Epicardial course of the musculature related to the great cardiac vein: Anatomical considerations and clinical implications for mitral isthmus block after vein of Marshall ethanol infusion.

Background: Mitral isthmus gaps have been ascribed to an epicardial musculature anatomically related to the great cardiac vein (GCV) and the vein of Marshall (VOM). Their lumen offers an access for radiofrequency application or ethanol infusion, respectively.

Objective: The purpose of this study was to evaluate the frequency of mitral isthmus gaps accessible via the GCV lumen, to assess their location around the GCV circumference, and to propose an efficient ablation strategy when present.

Persistent atrial fibrillation ablation in cardiac laminopathy: Electrophysiological findings and clinical outcomes.

Background: Little is known about persistent atrial fibrillation (AF) ablation in patients with cardiac laminopathy (CLMNA).

Objectives: We aimed to characterize atrial electrophysiological properties and to assess the long-term outcomes of persistent AF ablation in patients with CLMNA.

Methods: All patients with CLMNA referred in our center for persistent AF ablation were retrospectively included.

Differentiating atrial tachycardias with centrifugal activation: Lessons from high-resolution mapping.

Background: Centrifugal activation is not always the origin of a focal atrial tachycardia (AT) ("true-focal"), but passive activation from the other structures ("pseudo-focal").

Objective: We aimed to establish a method to differentiate true-focal from pseudo-focal.

Methods: In 49 centrifugal activations in 35 patients with AT, 12-lead electrocardiogram, activation map, atrial global activation histogram (GAH), and local electrograms were analyzed.

Ultralow temperature cryoablation: Safety and efficacy of preclinical atrial and ventricular lesions.

Background: Ultralow temperature cyroablation (ULTC) is designed to create focal, linear, and circumferential lesions. The aim of this study was to assess the safety, efficacy, and durability of atrial and ventricular ULTC lesions in preclinical large animal models.

Methods And Results: The ULTC system uses nitrogen near its liquid-vapor critical point to cool 11-cm ablation catheters.

Marshall bundle elimination, Pulmonary vein isolation, and Line completion for ANatomical ablation of persistent atrial fibrillation (Marshall-PLAN): Prospective, single-center study.

Background: Beyond pulmonary vein isolation (PVI), the optimal ablation strategy for persistent atrial fibrillation (AF) remains poorly defined.

Objective: The purpose of this study was to examine a novel comprehensive ablation strategy (Marshall bundle elimination, Pulmonary vein isolation, and Line completion for ANatomical ablation of persistent atrial fibrillation [Marshall-PLAN]) strictly based on anatomical considerations.

Methods: Left atrial (LA) sites were sequentially targeted as follows: (1) coronary sinus and vein of Marshall (CS-VOM) musculature; (2) PVI; and (3) anatomical isthmuses (mitral, roof, and cavotricuspid isthmus [CTI]).

Epicardial course of the septopulmonary bundle: Anatomical considerations and clinical implications for roof line completion.

Background: Gaps in the roof line have been ascribed to epicardial conduction using the septopulmonary bundle.

Objectives: We sought to evaluate the frequency of septopulmonary bundle bypass during roof line ablation, to describe anatomical conditions favoring this epicardial gap, and to propose an alternative strategy when present.

Methods: One hundred consecutive patients underwent atrial fibrillation ablation.

Temperature- and flow-controlled ablation/very-high-power short-duration ablation vs conventional power-controlled ablation: Comparison of focal and linear lesion characteristics.

Background: The QDOT MICRO catheter allows temperature- and flow-controlled (TFC) ablation and very-high-power short-duration (vHPSD) ablation.

Objective: The purpose of this study was to compare lesion characteristics between TFC/vHPSD ablation and standard power-controlled (PC) ablation.

Methods: Lesion characteristics in the right atrium, left atrium, and right ventricle (RV) of 6 sheep were compared between vHPSD (90 W/4 seconds, TC mode with 60°C target using QDOT) and standard radiofrequency settings (PC mode, 30 W/30 seconds with ThermoCool SmartTouch SF).

Automated rhythm-based control of radiofrequency ablation close to the atrioventricular node: Preclinical, animal, and first-in-human testing.

Background: The risk of heart block during radiofrequency ablation of atrioventricular (AV) nodal reentrant tachycardia and septal accessory pathways is minimized by rapidly ceasing ablation in response to markers of risk, such as atrioventricular dissociation, fast junctional rhythm, PR interval prolongation, or 2 consecutive atrial or ventricular depolarizations. Currently this is done manually.

Objectives: The objectives of this study were to build and test a control system able to monitor cardiac rhythm and automatically terminate ablation energy when required.

Insights Into the Spatiotemporal Patterns of Complexity of Ventricular Fibrillation by Multilead Analysis of Body Surface Potential Maps.

Background: Ventricular fibrillation (VF) is the main cause of sudden cardiac death, but its mechanisms are still unclear. We propose a noninvasive approach to describe the progression of VF complexity from body surface potential maps (BSPMs).

Methods: We mapped 252 VF episodes (16 ± 10 s) with a 252-electrode vest in 110 patients (89 male, 47 ± 18 years): 50 terminated spontaneously, otherwise by electrical cardioversion (DCC).

The 'double transition': a novel electrocardiogram sign to discriminate posteroseptal accessory pathways ablated from the right endocardium from those requiring a left-sided or epicardial coronary venous approach.

Aims: The precise localization of manifest posteroseptal accessory pathways (APs) often poses diagnostic challenges considering that a small area may encompass AP that may be ablated from the right or left endocardium, or epicardially within the coronary sinus (CS). We sought to explore whether the QRS transition pattern in the precordial lead may help to discriminate the necessary ablation approach.

Methods And Results: Consecutive patients who underwent a successful ablation of a single manifest AP over a 5-year period were included.

Impedance, power, and current in radiofrequency ablation: Insights from technical, ex vivo, and clinical studies.

Background: Radiofrequency (RF) power is routinely considered during RF application. In contrast, impedance has been relatively poorly studied, despite also influencing RF lesion creation. The aim of this study was to examine the influence of electric impedance on RF lesion characteristics and on clinical RF ablation parameters.

Characterization of Complex Atrial Tachycardia in Patients With Previous Atrial Interventions Using High-Resolution Mapping.

Objectives: This study systematically evaluated mechanisms of atrial tachycardia (AT) by using ultra-high-resolution mapping in a large cohort of patients.

Background: An incomplete understanding of the mechanism of AT is a major determinant of ablation failure.

Methods: Consecutive patients with ≥1 AT (excluding cavotricuspid isthmus-dependent flutter) were included.

Acute and mid-term outcome of ethanol infusion of vein of Marshall for the treatment of perimitral flutter.

Aims: We hypothesized that an epicardial approach using ethanol infusion in the vein of Marshall (EIVOM) may improve the result of ablation for perimitral flutter (PMF).

Methods And Results: We studied 103 consecutive patients with PMF undergoing high-resolution mapping. The first 71 were treated with radiofrequency (RF) ablation alone (RF-group), and the next 32 underwent EIVOM followed by RF on the endocardial and epicardial mitral isthmus (EIVOM/RF-group).

Atrial tachycardia circuits include low voltage area from index atrial fibrillation ablation relationship between RF ablation lesion and AT.

Background: No study to date has used high-density mapping to investigate the relationship between prior radiofrequency (RF) lesions for persistent atrial fibrillation (PsAF) ablation and subsequent atrial tachycardias (ATs).

Methods: From 41 consecutive patients who underwent AT ablation at a second procedure using an ultrahigh-density mapping system, 22 patients (38 ATs) were included as they also had complete maps with a multipolar catheter and three-dimensional (3D) mapping system at the time of the first PsAF ablation procedure. We, therefore, compared voltage maps from the first AF ablation procedure to those from the subsequent AT ablation procedure, as well as the lesion sets used for AF ablation vs the activation patterns in AT during the second procedure.

In silico analysis of the relation between conventional and high-power short-duration RF ablation settings and resulting lesion metrics.

Background: Use of lesion metric indices is a proposed strategy to support pulmonary vein isolation procedures and these indices show good correlations with lesion sizes. The aim of this in silico study is to provide a detailed analysis of radiofrequency (RF) settings, including high-power short-duration (HPSD) settings, and resulting lesion metric indices.

Methods And Results: A software program was designed which simulated virtual RF ablations.

Mechanism of Recurrence of Atrial Tachycardia: Comparison Between First Versus Redo Procedures in a High-Resolution Mapping System.

Background: Atrial fibrillation ablation-related atrial tachycardia (AT) is complex and may demonstrate several forms: anatomic macroreentrant AT (AMAT), non-AMAT, and focal AT. We aimed to elucidate the recurrence rate and mechanisms of atrial fibrillation ablation-related AT recurrence.

Methods: Among 147 patients with ATs treated with the Rhythmia system, 68 (46.

Ultra-High-Density Activation Mapping to Aid Isthmus Identification of Atrial Tachycardias in Congenital Heart Disease.

Objectives: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD).

Background: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit.

Does Ventricular Tachycardia Ablation Targeting Local Abnormal Ventricular Activity Elimination Reduce Ventricular Fibrillation Incidence?

Background: Various strategies for ablation of ventricular tachycardia (VT) have been described, but their impact on ventricular fibrillation (VF) is largely unknown. The aim of our study was to assess the effect of substrate-based VT ablation targeting local abnormal ventricular activity (LAVA) on recurrent VF events in patients with structural heart disease.

Methods: A retrospective 2-center study was performed on patients with structural heart disease and both VT and VF, with incident VT ablation procedures targeting LAVAs.