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Introduction : There are numerous challenges to catheter ablation in patients with congenital heart disease (CHD), including access to cardiac chambers, distorted anatomies, displaced conduction systems, multiple and/or complex arrhythmia substrates, and excessively thickened walls, or interposed material. Areas covered : Herein, we review recent developments in catheter ablation strategies for patients with CHD that are helpful in addressing these challenges. Expert opinion : Remote magnetic navigation overcomes many challenges associated with vascular obstructions, chamber access, and catheter contact. Patients with CHD may benefit from a range of ablation catheter technologies, including irrigated-tip and contact-force radiofrequency ablation and focal and balloon cryoablation. High-density mapping, along with advances in multipolar catheters and interpolation algorithms, is contributing to new mechanistic insights into complex arrhythmias. Ripple mapping allows the activation wave front to be tracked visually without prior assignment of local activation times or window of interest, and without interpolations of unmapped regions. There is growing interest in measuring conduction velocities to identify arrhythmogenic substrates. Noninvasive mapping with a multielectrode-embedded vest allows prolonged bedside monitoring, which is of particular interest in those with non-sustained or multiple arrhythmias. Further studies are required to assess the role of radiofrequency needle catheters and stereotactic radiotherapy in patients with CHD.

Background: High values of ECG and intracardiac dominant frequency (DF) are indicative of significant atrial remodeling in persistent atrial fibrillation (peAF). We hypothesized that patients with peAF unresponsive to ablation display higher ECG and intracardiac DFs than those remaining in sinus rhythm (SR) on the long term., Methods: Forty consecutive patients underwent stepwise ablation for peAF (sustained duration 19 ± 11 months). Electrograms were recorded before ablation at 13 left atrium (LA) sites and at the right atrial appendage (RAA) and coronary sinus (CS) synchronously to the ECG. DF was defined as the highest peak within the power spectrum., Results: peAF was terminated within the LA in 28 patients (left-terminated [LT]), whereas 12 patients remaining in AF after ablation (not left-terminated [NLT]) were cardioverted. Over a mean follow-up of 34 ± 14 months, all 12 NLT patients had a recurrence. Of the LT patients, 71% had a recurrence (20/28, LT_Rec), while 29% remained in SR throughout the follow-up (8/28, LT_SR). DF values and correlations between pairs of LA appendage (LAA), RAA, and CS DFs showed distinctive patterns among the subgroups. The NLT subgroup displayed the highest ECG and intracardiac DFs, with strong intragroup homogeneity between pairs of CS and LAA DFs, and to a lesser extent between pairs of CS and RAA DFs. Conversely, the LT_SR subgroup showed the lowest DFs, with significant intragroup heterogeneity between pairs of CS and both LAA and RAA DFs., Conclusions: Patients with peAF unresponsive to ablation show high surface and intracardiac DFs indicative of severe and uniform bi-atrial remodeling.

This review article provides a broad overview of the novelties in cardiology in 2018. Advances in interventional cardiology and cardiovascular prevention, heart failure, electrophysiology and non-invasive cardiovascular imaging have provided important new insights in the pathophysiology, diagnosis and treatment of ischemic and valvular heart disease, heart failure, rhythm disorders and cardiomyopathies. This article provides an overview of the most relevant articles published in 2018., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Objectives: This study evaluated a new algorithm relying on maximal pre-excitation., Background: Prior knowledge of accessory pathway (AP) location facilitates an individual ablation strategy. Delta-wave analysis on a 12-lead electrocardiogram is recognized as crucial for predicting ablation site, but can be ambiguous at basal state., Methods: An algorithm based on maximal pre-excitation, as induced by atrial pacing during an electrophysiological study, was initially developed in 132 patients with a single manifest AP. The maximally pre-excited QRS features included the global polarity in lead V 1 (step 1), inferior leads (step 2), and leads V 3 or I (step 3), as well as the morphology in lead II (step 4). Three investigators prospectively tested the new algorithm in 207 consecutive patients by comparing its efficacy to a control algorithm relying on basal pre-excitation., Results: The accuracy, defined as the percent of patients with an exact prediction of AP location, was significantly greater with the new algorithm (90% vs. 63%; p < 0.001). The reproducibility, defined as the level of agreement between investigators in determining AP location, was excellent (κ > 0.75; p < 0.05) with the new algorithm and fair (0.40 < κ < 0.75; p < 0.05) with the control algorithm., Conclusions: An algorithm based on maximal pre-excitation allows accurate and reproducible localization of manifest APs. When ablation is indicated, the analysis of maximal pre-excitation is a sensible approach for giving a head start in endocardial mapping., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The number of children and adult with congenital heart disease requiring implantation of cardiac pacemaker or cardioverter defibrillator is constantly increasing. The lead between stimulation/defibrillation site and the generator constitutes the main weakpoint of those devices despite the numerous recent technological advances: use of bipolar probes, corticoid elution electrodes, insulation improvement, magnetic resonance imaging (MRI) compatibility. Risk of device failure remains high in this population. Long term adverse events with endovascular devices remain high. That point leads us to review our implantation strategies. We try to favour an extravascular solution whenever possible. Subcutaneous defibrillators may be proposed to patients at high risk for severe ventricular arrhythmia without cardiac pacing indication. Patients should have a rigorous pre-implantation screening procedure to minimize the increased risk of inappropriate shock. New single chamber, VVIR-type, leadless pacemakers can be implanted directly into the right ventricle. Miniaturized implantable loop recorders help in management of palpitations and syncopes: it increases diagnosis yield and helps arrhythmias burden assessment. Development of remote monitoring (implantable loop recorder, pacemaker and defibrillator) helps to reduce the incidence of adverse clinical events by providing an early detection of clinically relevant events such as arrhythmias and device failure., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Supraventricular arrhythmias are an important and increasing cause of morbidity in adults with congenital heart disease, requiring specific management strategies. Pharmacological treatment has limited efficacy, and is often associated with some side-effects. Major improvements in catheter ablation techniques have opened new opportunities to better understand underlying mechanisms of supraventricular arrhythmias, offer better therapy, and eventually improve symptoms and quality of life in these patients. An array of tools and techniques are necessary to access relevant anatomical areas to address the arrhythmogenic substrate. The mechanism of these arrhythmias is mostly related to macroreentry around surgical scars or cavotricuspid isthmus-dependent flutter. The efficacy of catheter ablation is mainly dependent on the underlying congenital heart condition, with the most complex cases typically being associated with atrial switch and Fontan surgeries. Although relatively high rates of recurrence are seen after a single procedure, additional attempts are often helpful to decrease recurrences and improve symptoms. Catheter ablation in such patients continues to present many unique challenges that are best addressed by experienced multidisciplinary teams, at centres equipped with the proper catheters, imaging capabilities, mapping systems and support staff needed to maximize safety and success. Consensus indications have emerged that often support ablation as first-line therapy in these patients. In this comprehensive review, we aim to describe the specific issues associated with ablation of supraventricular arrhythmias in adult congenital heart disease, assess the results in contemporary practice and, finally, review the current indications., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)