Anatomical and Electrophysiological Characteristics of Dual-Loop Re-Entry in Atypical Atrial Flutter: Implications for Mapping and Catheter Ablation.

Atypical atrial flutter (AFL) can be challenging to ablate, especially when involving dual-loop re-entry. We sought to assess the electroanatomical characteristics of single- and dual-loop AFLs in patients undergoing catheter ablation. We analyzed 25 non-cavotricuspid isthmus-dependent macro-re-entrant AFL in 19 consecutive patients.

Early and Late Postoperative Tachyarrhythmias in Children and Young Adults Undergoing Congenital Heart Disease Surgery.

The population of patients with congenital heart disease is constantly growing with an increasing number of individuals reaching adulthood. A significant proportion of these children and young adults will suffer from tachyarrhythmias due to the abnormal anatomy, the hemodynamic burden, or as a sequela of surgical treatment. Depending on the underlying mechanism, arrhythmias may arise in the early postoperative period (hours to days after surgery) or in the late postoperative period (usually years after surgery).

Safety, Efficacy and Prognostic Benefit of Atrial Fibrillation Ablation in Heart Failure with Preserved Ejection Fraction.

Up to 65% of patients with heart failure with preserved ejection fraction (HFpEF) develop AF during the course of the disease. This occurrence is associated with adverse outcomes, including pump failure death. Because AF and HFpEF are mutually reinforcing risk factors, sinus rhythm restoration may represent a disease-modifying intervention.

Right Atrial Complexity Evolves With Stepwise Left-Sided Persistent Atrial Fibrillation Substrate Ablation and Predicts Outcomes.

Objectives: This study sought to study the relation between outcomes of modified stepwise atrial fibrillation (AF) substrate ablation and dynamic electrogram characteristics in the coronary sinus (CS) and right atrium (RA).

Background: Identifying patients with persistent AF who will benefit from limited lesion sets versus those requiring extensive substrate modification is challenging.

Methods: We studied 70 patients undergoing persistent AF ablation, 43 with acute success (successful ablation [sABL], AF termination, or noninducibility) and 27 with failure (failed ablation [fABL], no termination, or induced AF of >5 minutes).

Significance of post-pacing intervals shorter than tachycardia cycle length for successful catheter ablation of atypical flutter.

Aims: During entrainment mapping of macro-reentrant tachycardias, the time difference (dPPI) between post-pacing interval (PPI) and tachycardia cycle length (TCL) is thought to be a function of the distance of the pacing site to the re-entry circuit and dPPI < 30 ms is considered within the re-entry circuit. This study assessed the importance of PPI < TCL as a successful target for atypical flutter ablation.

Methods And Results: A total of 177 ablation procedures were investigated.

Sustained and self-terminating atrial fibrillation induced immediately after pulmonary vein isolation exhibit differences in coronary sinus electrical activity from onset.

Introduction: Little data exists on the electrophysiological differences between sustained atrial fibrillation (sAF; >5 minutes) vs self-terminating nonsustained AF (nsAF; <5 minutes). We sought to investigate the electrophysiological characteristics of coronary sinus (CS) activity during postpulmonary vein isolation (PVI) sAF vs nsAF.

Methods And Results: We studied 142 patients post-PVI for paroxysmal AF (PAF).

Individualised Approaches for Catheter Ablation of AF: Patient Selection and Procedural Endpoints.

Pulmonary vein isolation (PVI) is the cornerstone of AF ablation, but studies have reported improved efficacy with high rates of repeat procedures. Because of the large interindividual variability in the underlying electrical and anatomical substrate, achieving optimal outcomes requires an individualised approach. This includes optimal candidate selection as well as defined ablation strategies with objective procedure endpoints beyond PVI.

Electrophysiological and Anatomical Correlates of Sites With Postpacing Intervals Shorter Than Tachycardia Cycle Length in Atypical Atrial Flutter.

Background Although entrainment mapping is an established approach to atypical atrial flutter ablation, postpacing intervals shorter than tachycardia cycle length (difference between postpacing interval and tachycardia cycle length [dPPI] <0 ms) remain of unknown significance. We sought to compare anatomic and electrophysiological properties of sites with dPPI <0, dPPI=0-30, and dPPI >30 ms. Methods We studied 24 noncavotricuspid isthmus-dependent macroreentrant atypical atrial flutter in 19 consecutive patients.

Evolution of post-pulmonary vein isolation atrial fibrillation inducibility at redo ablation: Electrophysiological evidence of extra-pulmonary vein substrate progression.

Background: The electrophysiological substrate underlying atrial fibrillation (AF) progression remains difficult to identify.

Objective: The goals of this study were to study the evolution of post-pulmonary vein isolation (PVI) AF inducibility (AFI) after AF ablation and to compare patients with organized atrial tachycardia recurrence (OATr) versus those with paroxysmal or persistent AF recurrence.

Methods: We studied 99 patients who underwent de novo AF ablation (p1) and redo ablation (p2) for AF recurrence (AFr) or OATr.

Intra- and interatrial conduction abnormalities: hemodynamic and arrhythmic significance.

Alterations of normal intra- and interatrial conduction are a common outcome of multiple cardiovascular conditions. They arise most commonly in the context of advanced age, cardiovascular risk factors, organic heart disease, atrial fibrosis, and left atrial enlargement. Interatrial block (IAB), the most frequent and extensively studied atrial conduction disorder, affects up to 20% of the general primary care population.

Recipient Atrial Fibrillation Manifesting as an Irregular Monomorphic Atrial Tachycardia in the Donor Heart.

A 63-year-old man presented with a 1-year history of atrial tachycardia (AT) 6 years after orthotopic heart transplantation with bicaval anastomosis. Twelve-lead electrocardiogram showed monomorphic AT with isoelectric intervals across all leads and strikingly irregular PP intervals. At electrophysiology study, the native left atrium's rhythm was atrial fibrillation (AF) while the donor atria exhibited centrifugal activation of irregular cycle length originating from a site along the left atrial anastomosis.

Relationship between catheter contact force and radiofrequency lesion size and incidence of steam pop in the beating canine heart: electrogram amplitude, impedance, and electrode temperature are poor predictors of electrode-tissue contact force and lesion size.

Background: Electrode-tissue contact force (CF) is believed to be a major factor in radiofrequency lesion size. The purpose of this study was to determine, in the beating canine heart, the relationship between CF and radiofrequency lesion size and the accuracy of predicting CF and lesion size by measuring electrogram amplitude, impedance, and electrode temperature.

Methods And Results: Eight dogs were studied closed chest.

A novel radiofrequency ablation catheter using contact force sensing: Toccata study.

Objectives: The aim of this multicenter study was to evaluate the device- and procedure-related safety of a novel force-sensing radiofrequency (RF) ablation catheter capable of measuring the real-time contact force (CF) and to present CF data and its possible implications on patient safety.

Background: The clinical outcome of RF ablation for the treatment of cardiac arrhythmias may be affected by the CF between the catheter tip and the tissue. Insufficient CF may result in an ineffective lesion, whereas excessive CF may result in complications.

Area under the real-time contact force curve (force-time integral) predicts radiofrequency lesion size in an in vitro contractile model.

Introduction: Electrode tissue contact, radiofrequency (RF) power and duration are major determinants of RF lesion size. Since contact forces (CF) vary in the beating heart, we evaluated contact force-time integral (FTI) as a predictor of lesion size at constant RF power in a contractile bench model simulating the beating heart.

Methods And Results: An open-tip irrigated catheter was attached to a movable mount incorporating a dynamic force sensor allowing closed loop control to achieve desired force variations between the catheter tip and bovine skeletal muscle placed on a ground plate.

Novel contact force sensor incorporated in irrigated radiofrequency ablation catheter predicts lesion size and incidence of steam pop and thrombus.

Background: An open-irrigated radiofrequency (RF) ablation catheter was developed to measure contact force (CF). Three optical fibers measure microdeformation of the catheter tip. The purpose of this study was to (1) validate the accuracy of CF sensor (CFS) (bench test); and (2) determine the relationship between CF and tissue temperatures, lesion size, steam pop, and thrombus during RF ablation using a canine thigh muscle preparation.