Sequential ultrahigh-density contact mapping of persistent atrial fibrillation: An efficient technique for driver identification.

INTRODUCTION: Literature supports the existence of drivers as maintainers of atrial fibrillation (AF). Whether ultrahigh density (UHD) contact mapping may detect them is unknown. METHODS: We sequentially mapped the left atrial (LA) activation during spontaneous persistent AF and performed circumferential pulmonary vein isolation (CPVI), followed by remapping and ablation of potential drivers (rotational and focal propagation sites) with Rhythmia™ in 90 patients. The time reference was an LA appendage (LAA) electrogram (EGM). Regions with uniform color were defined as "organized." Only patients (51) with no previous ablation were considered for acute results and follow-up reporting. RESULTS: LA maps (175 ± 28 ml, 43578 ± 18013 EGM) were acquired in 23 ± 7 min. In all post-CPVI maps potential drivers (7.3 ± 3.2/patient) were visualized: 85% with rotational propagation and continuous low voltage in the center; the remaining with focal propagation and an organized EGM at the site of earliest activation. The RF delivery time for extra-PV driver ablation was 12.2 ± 7.9 min. There was a progressive increase of AF organization: the LAA cycle length prolonged, the number of potential drivers decreased, and the organized LA surface in AF increased from 14 ± 6% to 28 ± 16% (p = .0007). Termination of AF without cardioversion was obtained in 67%. AF recurrence rate at 15 ± 7.3 months was 17.6% after the first procedure. CONCLUSIONS: Sequential UHD contact activation mapping of persistent AF allows visualization of potential drivers. A sequential strategy of CPVI followed by ablation of potential drivers with limited RF time resulted in an increasing organization of AF and good acute and long-term results.

Management of sleep apnoea syndrome (SAS) in patients with vasovagal syncope (VVS): a protocol for the VVS-SAS cohort study.

INTRODUCTION: Recurrent vasovagal syncope (VVS) is associated with decreased quality-of-life and frequent use of emergency services. The evidence base for causality, diagnostic procedures and potential VVS treatments is poor. Scattered observations in the literature suggest a link between respiratory disturbances during sleep and VVS. Empirical observations lead us to further hypothesise that the appropriate management of sleep apnoea syndrome (SAS) may help resolve comorbid recurrent VVS in certain patients. We therefore designed this pilot study to provide a framework for the observation of changes in outcomes accompanying the deployment of SAS treatments in patients with VVS. METHODS AND ANALYSIS: This is a multicentre, registry-based study whose primary objective is to evaluate the effect of SAS management on the number of syncope/presyncope episodes in a population suffering from both VVS and SAS. To this effect, syncope rates prior to the treatment of SAS will be compared with those occurring after the initiation of the latter. In addition, yearly assessments will collect data for echocardiography, polysomnography, Holter monitoring, table tilt tests, multiple sleep latency tests, SAS management parameters and questionnaires describing fatigue, depression and quality-of-life. Sixty patients will be included with a minimum follow-up period of 12 months. The primary analysis will use comparisons of centrality for paired data to describe the changes in syncope rates before versus after the initiation of SAS management. Longitudinal data will be analysed using mixed models with patients set as a random effect. Subgroup analyses will be performed for SAS-treatment adherence and efficacy. ETHICS AND DISSEMINATION: The VVS-SAS registry was approved by an ethics committee (Comité pour la Protection des Personnes Ile-de-France VI, Reference number CPP/2-18) in accordance with French law. The princeps publication will present before-after SAS management results and longitudinal analyses. TRIAL REGISTRATION NUMBER: NCT04294524. Pre-results.

The Left Atrio-Vertebral Ratio: a new simple means for assessing left atrial enlargement on Computed Tomography.

OBJECTIVE: The purpose of this study is to describe a new method to quickly estimate left atrial enlargement (LAE) on Computed Tomography. METHODS: Left atrial (LA) volume was assessed with a 3D-threshold Hounsfield unit detection technique, including left atrial appendage and excluding pulmonary venous confluence, in 201 patients with ECG-gated 128-slice dual-source CT and indexed to body surface area. LA and vertebral axial diameter and area were measured at the bottom level of the right inferior pulmonary vein ostium. Ratio of LA diameter and surface on vertebra (LAVD and LAVA) were compared to LA volume. In accordance with the literature, a cutoff value of 78 ml/m2 was chosen for maximal normal LA volume. RESULTS: 18% of LA was enlarged. The best cutoff values for LAE assessment were 2.5 for LAVD (AUC: 0.65; 95% CI: 0.58-0.73; sensitivity: 57%; specificity: 71%), and 3 for LAVA (AUC: 0.78; 95% CI: 0.72-0.84; sensitivity: 67%; specificity: 79%), with higher accuracy for LAVA (P=0.015). Inter-observer and intra-observer variability were either good or excellent for LAVD and LAVA (respective intraclass coefficients: 0.792 and 0.910; 0.912 and 0.937). CONCLUSION: A left atrium area superior to three times the vertebral area indicates LAE with high specificity. KEY POINTS: • Left atrial enlargement is a frequent condition associated with poor cardiac outcome. • Left atrial enlargement is highly time-consuming to diagnose on CT. • The left atrio-vertebral ratio quickly assesses left atrial enlargement. • A left atrial area > three times vertebral area is highly specific.

Pacemakers implantation and radiofrequency catheter ablation procedures during medical missions in Morocco: an 8-year experience.

AIMS: Radiofrequency catheter ablation (RFCA) for arrhythmias in the context of short-term medical missions (MM) in a developing country has not been reported so far. We describe here our experience with RFCA and pacemaker implantation in Morocco with a fully portable electrophysiological (EP) system under the auspice of the Monaco-Morocco Cardiology Association. METHODS AND RESULTS: Since November 2007, two to three MM (mean duration 4 days including transportation) per year were conducted (including two physicians and one nurse from Monaco) and were alternately located in Marrakech, Fes, Agadir, Casablanca, Rabat, Essaouira, and Oujda. All patients' files were sent by local teams and/or referring Moroccan cardiologists before MM. Each case was discussed with the Monaco EP team before the MM. Pacemakers and leads were donated by companies (Sorin Group, Medtronic, Saint-Jude Medical). The EP system (EP Tracer, CardioTek) as well as diagnostic/ablation catheters were brought for RFCA procedures. After the procedures, follow-up was performed by local teams. Procedures took place in gynaecological or orthopaedic operating room, or, when available, in the interventional cardiology cathlab. Thirty-one RFCA were performed during 11 MM (atrioventricular node re-entrant tachycardia = 12; atrioventricular re-entrant tachycardia/Mahaïm fibre = 15; typical atrial flutter = 3; ventricular ectopy = 1). Acute success was 93.5% for RFCA. Two major RFCA-related complications occurred (air embolism and complete atrioventricular block). No complication was related to pacemaker implantations (n = 44; mean 4 pacemakers per mission). CONCLUSION: Radiofrequency catheter ablation for arrhythmias in developing countries is technically challenging but feasible, despite technical and cultural difficulties.

Slow pathway radiofrequency ablation in patients with AVNRT: junctional rhythm is less frequent during magnetic navigation ablation than with the conventional technique.

INTRODUCTION: The occurrence of accelerated junctional rhythm (JR) during radiofrequency ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT) is frequent. The aim of the present study was to compare the occurrence of JR during magnetic remote catheter ablation to the conventional manual ablation. METHODS AND RESULTS: Twenty six patients (males: seven; age: 51 + or - 15 years) underwent slow pathway ablation with magnetic navigation (MN) system (Niobe, Stereotaxis Inc., St. Louis, MO, USA) and were compared to a control group of 11 patients (males: three; age: 53 + or - 16 years) treated with conventional manual ablation. A 4-mm nonirrigated tip catheter was used in both groups with a maximum of 30 W and 60 degrees C. Acute success was obtained in all patients. In the MN group, three patients out of 24 had no junctional beat (JB) at all and seven patients had 10 or less JB. In contrast, in the conventional group no patient had less than 10 JB. The mean number of JB in the MN group was 66 + or - 94.9 (0-410) and 200 + or - 243.1 (43-914) in the control group (P = 0.019). In the MN group one patient had a first-degree atrioventricular block. No other complication occurred. CONCLUSIONS: Magnetic remote catheter ablation of AVNRT is effective and is associated with less JB than the manual conventional technique. Therefore, JB may not be considered as a mandatory indicator for successful AVNRT ablation with MN system.

Robotic magnetic navigation for ablation of human arrhythmias: initial experience.

BACKGROUND: Magnetic navigation system (MNS) (Niobe, Stereotaxis, Saint-Louis, Missouri, USA) allows remote control of a radiofrequency ablation catheter using a steerable magnetic field and a catheter advancement system. AIMS: We report our initial experience of ablation of human arrhythmias using the MNS. METHODS: Eighty-four patients (mean age 54+/-17years; 39 women) had an electrophysiologic study followed by ablation with the MNS using non-irrigated 4, 8 and 3.5mm-tip catheters with three distal magnets. All patients were symptomatic, with commonly-accepted indications for ablation: atrioventricular nodal re-entrant tachycardia (AVNRT; n=37); typical atrial flutter (n=15); accessory pathway (n=12); atypical atrial flutter (n=7); ventricular tachycardia (n=7); atrial tachycardia (n=3); paroxysmal atrial fibrillation (n=3). Electroanatomical mapping was used for atrial flutter, atrial fibrillation, atrial tachycardia and ventricular tachycardia procedures (29 patients, 34%). RESULTS: Ablation was performed successfully in 69 (82%) patients. In 15 patients (18%), MNS technique was unsuccessful: seven typical atrial flutters, four accessory pathways, two left atrial flutters after atrial fibrillation ablation, one ventricular tachycardia and one AVNRT; in all these cases except one typical atrial flutter and two left atrial flutters, success was obtained by switching to the manual technique by means of an irrigated catheter. Total fluoroscopy time was 14+/-11minutes; operator exposure fluoroscopy time was 1.5+/-0.6minutes; procedure time was 169+/-72minutes. CONCLUSION: MNS ablation is a feasible treatment for various human arrhythmias, with a high success rate. Mapping with a magnetic catheter is safe. However, magnetic ablation of typical atrial flutter remains challenging, probably because of insufficient pressure for cavotricuspid isthmus ablation.

Clinical predictors of cardiac events in patients with isolated syncope and negative electrophysiologic study.

BACKGROUND: Patients with syncope or near syncope of unknown etiology represent a great challenge to cardiologists. An initial symptomatic episode triggers a series of diagnostic analysis which remain unsatisfactory when negative. More invasive tools such as electrophysiologic testing yield only partial answers to risk stratification while the complementary implantable holter diagnostics are not usually considered until a recurrent episode is documented. OBJECTIVE: This study targets predictors of significant cardiac rhythmic events in patients with a reported episode of syncope or near syncope presenting with negative diagnostics and electrophysiologic study results (EPS). A significant cardiac rhythmic event was defined as a combined end-point of (1) symptomatic AV block; (2) symptomatic conduction abnormalities requiring pacemaker therapy; (3) symptomatic sustained ventricular arrhythmia; and (4) sudden death. METHODS: All patients undergoing EPS after a first episode of syncope or presyncope between January 1997 and December 2001 were included for analysis. The study population consisted of 329 pts (42.6% women), 21 to 96 years old (mean 70+/-15 years) referred for an EP study for syncope or near syncope. RESULTS: Of the 329 patients who underwent EPS, 305 (92.7%) had follow-up data. The population, mean age 70 (+/- 15 years) and composed of 42% women, presented with hypertension (51.5%), diabetes mellitus (14.4%), hypercholesterolemia (30%), tobacco use (35%), a familial history of coronary heart disease (22%), history of stroke (4%), history of MI (12%), history of atrial fibrillation (10%), structural heart disease (17.4%), left ventricular ejection fraction 61 (+/- 11%) and ECG abnormalities (37%). These anomalies included right (RBBB) or left (LBBB) bundle branch blocks, left anterior fascicular block (LAFB), left posterior fascicular block (LPFB), bifascicular block (RBBB+LAFB) and traces of myocardial infarction. The mean follow-up was 31+/-20 months with 5% of patients recording significant cardiac rhythmic events (15/305): AV block requiring pacemaker therapy in 7 patients, sinus dysfunction in 4, sudden death in 3 and ventricular tachycardia in 1. Univariate analysis reveals structural heart disease, ECG abnormalities and LVEF associated with the risk of significant cardiac rhythmic events defined by the combined end-point. Multivariate analysis using a Cox model found that the only independent predictor of events was an ECG abnormality. The long-term risk of significant event in the subset with ECG abnormalities is of 10.6% (12/113). If unexplained syncope recurrence was included in the combined end-point, ECG abnormality and LVEF were both determinants with a 13.3% (15/113) risk of a arrhythmic events analysis in the subset of patients presenting with ECG abnormalities and Cox model found ECG abnormality as the only independent predictor of event. CONCLUSIONS: This study demonstrated that an ECG abnormality is the only predictive variable associated with a significant arrhythmic event in patients with a lone episode of syncope or near syncope and a negative EPS.