0166: New measurement of A/V ratio on the mitral annulus: interest in ablation

IntroductionMany ablations require radiofrequency delivery near to the mitral annulus (MA).No reliable data exists about the electrical criteria of mitral annulus localisation. The aim of this study was to measure the A/V ratio on the mitral annulus and compare it to the A/V ratio on its atrial and ventricular side with transesophageal echocardiographic guidance and catheter tissue contact monitoring.MethodsTen patients in sinus rhythm undergoing atrial fibrillation catheter ablation under general anesthesia using a contact-force sensing catheter were included. After double transseptal puncture, we recorded the atrial and ventricular potentials on the mitral annulus at four defined points (3,6,9 and 12 o’clock), with direct confirmation of the position of the catheter relative to the mitral annulus by transesophageal echocardio-graphy and contact assessment by the force sensor on the catheter tip. Then we performed the same procedure on the atrial and ventricular sides of the mitral annulus.ResultsThere is a homogeneous distribution of the amplitude of the atrial and ventricular electrograms on the mitral annulus with a good correlation (r=0,93; p < 0,0001). The mean A/V ratio was 0,57 (± 0,078, IC 95% 0,540,59) on the mitral annulus, 0,725 (± 0,09, IC 0,65-0,79) on the atrial side and 0,348 (± 0,09, IC 95% 0,18-0,41) on the ventricular side near to the mitral annulus. These results were significantly different (p< 0,0001). No correlation was found between this ratio and the size of the left atrium, left ventricular mass and the presence of hypertension.ConclusionsA/V ratio on the MA is 0.57. It is significantly different from the A/V ratio on the atrial and ventricular sides of the MA, and may be used as an electrical criterion for MA localisation during ablation proceduresAbstract 0166 – Figur

High-density mapping of the average complex interval helps localizing atrial fibrillation drivers and predicts catheter ablation outcomes

BackgroundPersistent Atrial Fibrillation (PersAF) electrogram-based ablation is complex, and appropriate identification of atrial substrate is critical. Little is known regarding the value of the Average Complex Interval (ACI) feature for PersAF ablation.ObjectiveUsing the evolution of AF complexity by sequentially computing AF dominant frequency (DF) along the ablation procedure, we sought to evaluate the value of ACI for discriminating active drivers (AD) from bystander zones (BZ), for predicting AF termination during ablation, and for predicting AF recurrence during follow-up.MethodsWe included PersAF patients undergoing radiofrequency catheter ablation by pulmonary vein isolation and ablation of atrial substrate identified by Spatiotemporal Dispersion or Complex Fractionated Atrial Electrograms (&gt;70% of recording). Operators were blinded to ACI measurement which was sought for each documented atrial substrate area. AF DF was measured by Independent Component Analysis on 1-minute 12-lead ECGs at baseline and after ablation of each atrial zone. AD were differentiated from BZ either by a significant decrease in DF (&gt;10%), or by AF termination. Arrhythmia recurrence was monitored during follow-up.ResultsWe analyzed 159 atrial areas (129 treated by radiofrequency during AF) in 29 patients. ACI was shorter in AD than BZ (76.4 ± 13.6 vs. 86.6 ± 20.3 ms; p = 0.0055), and mean ACI of all substrate zones was shorter in patients for whom radiofrequency failed to terminate AF [71.3 (67.5–77.8) vs. 82.4 (74.4–98.5) ms; p = 0.0126]. ACI predicted AD [AUC 0.728 (0.629–0.826)]. An ACI &lt; 70 ms was specific for predicting AD (Sp 0.831, Se 0.526), whereas areas with an ACI &gt; 100 ms had almost no chances of being active in AF maintenance. AF recurrence was associated with more ACI zones with identical shortest value [3.5 (3–4) vs. 1 (0–1) zones; p = 0.021]. In multivariate analysis, ACI &lt; 70 ms predicted AD [OR = 4.02 (1.49–10.84), p = 0.006] and mean ACI &gt; 75 ms predicted AF termination [OR = 9.94 (1.14–86.7), p = 0.038].ConclusionACI helps in identifying AF drivers, and is correlated with AF termination and AF recurrence during follow-up. It can help in establishing an ablation plan, by prioritizing ablation from the shortest to the longest ACI zone

Technological advances in cardiac pacing and defibrillation

Since more than a half century, cardiac pacing and defibrillation represent a field in constant evolution, and they have shown some great technological advances from its conception to its methods of insertion. In this review, the recent developments about the accesses for pacemakers and ICD will be described: the axillary and the femoral vein. The His bundle pacing and the advantages of the entirely subcutaneous defibrillator will also be presented

Quantification of cardiac fibrosis by magnetic resonance imaging and endocardial mapping

La fibrose cardiaque fait le lit des arythmies cardiaques, qu’elles soient atriales ou ventriculaires. L’IRM est devenue un outil non invasif indispensable pour diagnostiquer la présence de fibrose au niveau cardiaque, mais offre également des informations pronostiques, ainsi que pour le suivi des patients atteints de fibrillation auriculaire (FA), notamment persistante. La technique de référence reste le rehaussement tardif après injection de gadolinium, permettant de révéler des régions localisées de fibrose. Notre travail a consisté en la mise au point d’une technique non invasive (par la mesure du T2 avec IRM à haut champ à 11,75 T) afin de quantifier la fibrose myocardique interstitielle diffuse dans un modèle de souris diabétiques. La fibrose a été significativement corrélée à une survenue plus importante des arythmies ventriculaires en comparaison avec un groupe de souris contrôles. L’étape suivante a été de transposer cette technique de mesure de T2 en IRM clinique chez des patients devant bénéficier d’une procédure d’ablation de FA. La deuxième technique, cette fois-ci invasive pour évaluer la fibrose (notamment atriale) pour les patients atteints de FA est la cartographie de voltage au niveau de l’oreillette gauche. Nous avons utilisé un nouveau système de cartographie à ultra-haute définition afin de quantifier la fibrose (zones cicatricielles denses) correspondant aux régions dont les signaux enregistrés avaient une amplitude bipolaire inférieure à 0,015 mV, soit très en deçà des seuils précédemment rapportés concernant la fibrose.Fibrosis represents the main substrate for cardiac arrhythmias, either atrial or ventricular. MRI has become a critical tool to not only diagnose the presence of cardiac fibrosis, but also provides important informations on the prognosis and the follow-up of patients with atrial fibrillation (AF), especially in its persistent type. The gold standard is the Late Gadolinium Enhancement, allowing to reveal localized regions of fibrosis. Our study reported a technique for non invasive quantification of interstitial diffuse ventricular fibrosis in diabetic mice (T2 measurement high field MRI at 11,75 T). This fibrosis was significantly correlated to the occurrence of ventricular arrhythmias in comparison with the control group. The next step was the transposition of this T2 measurement with MRI in the clinical setup of patients who undergo an AF ablation procedure. The second technique for atrial fibrosis assessment for patients suffering from AF is the invasive realization of left atrial voltage mapping. A new ultra-high definition system was used to quantify the fibrosis (dense scar) in regions with bipolar amplitude electrograms of less than 0,015 mV. This cutoff was far lower than the previously published definition of the dense scar in the literature (< 0,1 mV)

Modifications de l'onde P après ablation par radiofréquence de la fibrillation atriale

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF

Atrial fibrillation ablation in a single atrium with inferior vena cava interruption

Abstract Common atrium (CA), also called three‐chambered heart, is one of the rare congenital anomalies, defined by a complete absence of the atrial septum, eventually associated with malformation of the atrioventricular (AV) valves. We report the case of a 57‐year‐old woman with CA complicated with Eisenmenger syndrome and inferior vena cava interruption, who suffered from symptomatic persistent atrial fibrillation (AF). She underwent an initial successful pulmonary vein isolation procedure. A repeat procedure for perivalvular atrial flutter was complicated with inadvertent complete AV block, due to unusual AV node location in this challenging anatomy