Feasibility of unipolar signal-guided ablation in creating contiguous lines of conduction block: A proof-of-concept study.

Background: Modification of the atrial unipolar electrogram (Uni-) with loss of the near-field negative component in response to radiofrequency (RF) ablation reflects transmural loss of tissue conductivity.

Objective: This study sought to investigate the feasibility of Uni- morphology-guided RF ablation in generating contiguous, transmural lesions that result in conduction block. This method was compared with ablation guided by standard ablation index parameters.

Efficacy of Pulsed Field vs Radiofrequency for the Reablation of Chronic Radiofrequency Ablation Substrate: Redo Pulsed Field Ablation.

Background: The efficacy of pulsed field ablation (PFA) for redo procedures is unknown.

Objectives: In this study, the authors aimed to evaluate the effectiveness of PFA when performing PFA over chronic RFA (redo environment).

Methods: This was a 3-step in vivo study.

Lattice-tip catheter for single-shot pulmonary vein isolation with pulsed field ablation.

Background: A compressible lattice-tip catheter designed for focal ablation using radiofrequency or pulsed-field energies has been recently described. The objective of this study is to describe a new lattice catheter designed for single-shot pulmonary vein isolation (PVI).

Methods: This 8F catheter consists of a compressible lattice tip that is delivered over the wire and is expandable up to 34 mm (SpherePVI™, Affera Inc.

Effect of Pulsed-Field and Radiofrequency Ablation on Heterogeneous Ventricular Scar in a Swine Model of Healed Myocardial Infarction.

Background: Pulsed-field ablation (PFA) is a nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation (RFA). We compared the effects of PFA and RFA on heterogeneous ventricular scar in a swine model of healed infarction.

Methods: In 9 swine, myocardial infarction was created by balloon occlusion of the left anterior descending artery.

Increasing Lesion Dimensions of Bipolar Ablation by Modulating the Surface Area of the Return Electrode.

Objectives: This study sought to examine the effect of the return electrode's surface area on bipolar RFA lesion size.

Background: Bipolar radiofrequency ablation (RFA) is typically performed between 2 3.5-mm tip catheters serving as active and return electrodes.

How to use bipolar and unipolar electrograms for selecting successful ablation sites of ventricular premature contractions.

Background: Local activation time is often determined by the maximal negative of the extracellular unipolar potential (-dV/dT). While this is accurate in 2-dimensional uniform tissue, propagation through nonuniform or 3-dimensional structures have shown discordance between -dV/dT and local activation time.

Objective: The purpose of this study was to examine the relationship between bipolar and unipolar electrograms for selecting successful ablation sites of endocardial (superficial) vs intramural (deep) ventricular premature contractions (VPCs).

Direction-aware mapping algorithms have minimal impact on bipolar voltage maps created using high-resolution multielectrode catheters.

Introduction: Direction-aware mapping algorithms improve the accuracy of voltage mapping by measuring the maximal voltage amplitude recorded in the direction of wavefront propagation. While beneficial for stationary catheters, its utility for roving catheters collecting electrograms (EGMs) at multiple angles is unknown.

Objective: To compare the directional dependence of bipolar voltage amplitude between stationary and roving catheters.

Pulsed-Field Ablation in Ventricular Myocardium Using a Focal Catheter: The Impact of Application Repetition on Lesion Dimensions.

[Figure: see text].

Propagation Vectors Facilitate Differentiation Between Conduction Block, Slow Conduction, and Wavefront Collision.

[Figure: see text].

Impact of High-Power Short-Duration Radiofrequency Ablation on Long-Term Lesion Durability for Atrial Fibrillation Ablation.

Objectives: The goal of this study was to compare lesion durability between high-power short-duration (HP-SD) and moderate-power moderate-duration (MP-MD) ablation strategies.

Background: HP-SD radiofrequency ablation (RFA) was developed to improve pulmonary vein isolation (PVI) by reducing the effect of catheter instability inherent to MP-MD ablation strategies. However, its long-term effect on lesion durability for the treatment of atrial fibrillation is unknown.