C. Tondo

Image integration increases efficacy of paroxysmal atrial fibrillation catheter ablation: Results from the CartoMerge™ italian Registry

AIMSnThe aim of this study was to investigate whether circumferential pulmonary vein (PV) isolation guided by image integration improves the procedural and clinical outcomes of atrial fibrillation (AF) ablation in comparison with segmental PV isolation and circumferential PV isolation guided by three-dimensional (3D) electroanatomical mapping alone.nnnMETHODS AND RESULTSnProcedural and clinical outcomes of 573 patients who underwent their first catheter ablation for paroxysmal AF between January 2005 and April 2007 were collected from 12 centres. We evaluated three techniques: segmental ostial PV isolation (SOCA group, 240 patients), circumferential PV isolation guided by electroanatomical mapping (CARTO group, 107 patients), and circumferential PV isolation guided by electroanatomical mapping integrated with magnetic resonance/computed tomographic images of the left atrium (MERGE group, 226 patients). Procedure duration proved to be shorter in MERGE group patients than in CARTO group patients (P < 0.04), but longer than in SOCA group patients (P < 0.0001). During follow-up, atrial tachyarrhythmias relapsed more frequently in SOCA group patients (44.6%) and CARTO group patients (41.7%) than in MERGE group patients (22.6%; P < 0.0001).nnnCONCLUSIONnIn patients with paroxysmal AF, circumferential PV isolation guided by image integration significantly improves clinical outcome in comparison with both circumferential PV isolation guided by 3D mapping alone and with segmental electrophysiologically guided PV isolation.

The durability of pulmonary vein isolation using the visually guided laser balloon catheter: Multicenter results of pulmonary vein remapping studies

BACKGROUNDnThe visually guided laser ablation (VGLA) catheter is a compliant, variable-diameter balloon that delivers laser energy around the pulmonary vein (PV) ostium under real-time endoscopic visualization. While acute PV isolation has been shown to be feasible, limited data exist regarding the durability of isolation.nnnOBJECTIVEnWe sought to determine the durability of PV isolation following ablation using the balloon-based VGLA catheter.nnnMETHODSnThe VGLA catheter was evaluated in patients with paroxysmal atrial fibrillation (3 sites, 10 operators). Following transseptal puncture, the VGLA catheter was advanced through a 12-F deflectable sheath and inflated at the target PV ostium. Under endoscopic guidance, the 30° aiming arc was maneuvered around the PV and laser energy was delivered to ablate tissue in a contiguous/overlapping manner. At ∼3 months, all patients returned for a PV remapping procedure.nnnRESULTSnIn 56 patients, 202 of 206 PVs (98%) were acutely isolated. At 105 ± 44 (mean ± SD) days, 52 patients returned for PV remapping at which time 162 of 189 PVs (86%) remained isolated and 32 of 52 patients (62%) had all PVs still isolated. On comparing the operators performing <10 vs ≥ 10 procedures, the durable PV isolation rate and the percentage of patients with all PVs isolated were found to be 73% vs 89% (P = .011) and 57% vs 66% (P = .746), respectively. After 2 procedures and 12.0 ± 1.9 months of follow-up, the drug-free rate of freedom from atrial fibrillation was 71.2%.nnnCONCLUSIONSnIn this multicenter, multioperator experience, VGLA resulted in a very high rate of durable PV isolation with a clinical efficacy similar to that of radiofrequency ablation.

Electrophysiological characteristics and outcome in patients with idiopathic right ventricular arrhythmia compared with arrhythmogenic right ventricular dysplasia

Background: Idiopathic right ventricular arrhythmias (IRVA) are responsive to medical and ablative treatment and have a benign prognosis. Arrhythmias caused by right ventricular dysplasia (ARVD) are refractory to treatment and may cause sudden death. It is difficult to distinguish between these two types of arrhythmia. Objective: To differentiate patients with IRVA and ARVD by a conventional electrophysiological study. Methods: 56 patients with a right ventricular arrhythmia were studied. They had no history or signs of any cardiac disease other than right ventricular dysplasia. They were classified as having IRVA (n = 41) or ARVD (n = 15) on the basis of family history, ECG characteristics, and various imaging techniques. They were further investigated by standard diagnostic electrophysiology. Results: The two groups were clearly distinguished by the electrophysiological study in the following ways: inducibility of ventricular tachycardia by programmed electrical stimulation with ventricular extrastimuli (IRVA 3% v ARVD 93%, p < 0.0001); presence of more than one ECG morphology during tachycardia (IRVA 0% v ARVD 73%, p < 0.0001); and fragmented diastolic potentials during ventricular arrhythmia (IRVA 0% v ARVD 93%, p < 0.0001). Data from the clinical follow up in these patients supported the diagnosis derived from the electrophysiological study. Conclusions: Patients with IRVA or ARVD can be distinguished by specific electrophysiological criteria. A diagnosis of ARVD can be made reliably on the basis of clinical presentation, imaging techniques, and an electrophysiological study.

Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy

Fibro-adipose substitution has a double detrimental effect on the myocardium in arrhythmogenic cardiomyopathy (ACM), worsening arrhythmogenesis by creating a non-conductive substrate, and causing ventricular dysfunction leading to heart failure. Notably, to-date no etiological therapy is available. This work introduces, for the first time, the stromal cardiac compartment as a key player in ACM ventricular adipose substitution: we demonstrated that cardiac human mesenchymal stromal cells undergo adipogenic differentiation both in ACM explanted hearts and in culture through a PKP2-dependent mechanism. Cardiac mesenchymal stromal cells constitute a suitable cellular platform for future mechanistic studies and a potential target for future therapies.

Rhythm‐Symptom Correlation in Patients on Continuous Monitoring After Catheter Ablation of Atrial Fibrillation

Correlation between symptoms and atrial fibrillation (AF) episodes after catheter ablation may have clinical relevance, especially for anticoagulation usage. The aim of our project was to analyze the relationship between symptoms and AF recurrences in unselected patients following AF catheter ablation during long‐term follow‐up.

Right ventricular substrate mapping using the Ensite Navx system: Accuracy of high-density voltage map obtained by automatic point acquisition during geometry reconstruction

BACKGROUNDnContact point-to-point electroanatomic mapping (Pt-Map) is a validated tool to evaluate right ventricular (RV) substrate. When using the EnSite NavX system (St. Jude Medical, St Paul, Minnesota), geometry reconstruction by dragging the mapping catheter (Geo-Map) allows for quicker acquisition of a large number of points and better definition of anatomy, but it is not validated for substrate mapping.nnnOBJECTIVEnThis study evaluates the feasibility and accuracy of Geo-Map.nnnMETHODSnThirteen patients (mean age 38 +/- 12 years) with RV arrhythmias and an apparently normal heart underwent cardiac magnetic resonance imaging (MRI), Pt-Map, and Geo-Map. The 2 maps were compared in terms of mapping procedural time, radiation time, and total number of points acquired. We finally compared the number and characteristics of low-potential areas on each patients Pt-Map, Geo-Map, and cardiac MRI.nnnRESULTSnGeo-Map required significantly shorter mapping and radiation times in comparison to Pt-Map (12.4 +/- 4.6 vs. 31.9 +/- 10.1 and 5.8 +/- 2.1 vs. 12.1 +/- 3.9, P <.001). Furthermore, Geo-Map was based on a significantly higher density of points in comparison to Pt-Map (802 +/- 205 vs. 194 +/- 38, P <.001). Taking into consideration the total number of RV regions analyzed, the Pt-Map and Geo-Map disagreed in 2 of 65 (3%) regions (P = NS), which only Geo-Map identified as low-potential areas and indeed corresponded to wall motion abnormalities on MRI.nnnCONCLUSIONnVoltage maps obtained through RV geometry acquisition have accuracy comparable to that of conventional point-by-point mapping in detecting low-voltage areas, have a good correlation with MRI wall motion abnormalities, and allow a significant reduction in procedural time and x-ray exposure.

Prevalence of left atrial thrombus in patients with non-valvular atrial fibrillation. A systematic review and meta-analysis of the literature.

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8u2009% (95u2009%CI: 7.6u2009%-12.5u2009%). LAT presence was associated with a higher age (mean difference: 2.56, 95u2009%CI: 1.49-3.62), and higher prevalence of female gender (OR: 1.35, 95u2009%CI: 1.04-1.75), hypertension (OR: 1.78, 95u2009%CI: 1.38-2.30), diabetes mellitus (OR: 1.86, 95u2009%CI: 1.33-2.59) and chronic heart failure (OR: 3.67, 95u2009%CI: 2.40-5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95u2009%CI: 0.68-1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95u2009%CI: 2.24-5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: -7.3, p<u20090.001). Indeed, studies in which 100u2009% of patients received oral anticoagulation reported a 3.4u2009% WMP of LAT (95u2009%CI: 1.3u2009%-8.7u2009%), whereas studies in which 0u2009% of patients received anticoagulation showed a LAT WMP of 7.4u2009% (95u2009%CI: 2.3u2009%-21.5u2009%). Our data suggest that LAT is present in ≍10u2009% of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

Role of Intracardiac echocardiography in Atrial Fibrillation Ablation

In the recent years, several new evidences support catheter-based ablation as a treatment modality of atrial fibrillation (AF). Based on a plenty of different applications, intracardiac echocardiography (ICE) is now a well-established technology in complex electrophysiological procedures, in particular in AF ablation. ICE contributes to improve the efficacy and safety of such procedures defining the anatomical structures involved in ablation procedures and monitoring in real time possible complications. In particular ICE allows: a correct identification of the endocardial structures; a guidance of transseptal puncture; an assessment of accurate placement of the circular mapping catheter; an indirect evaluation of evolving lesions during radiofrequency (RF) energy delivery via visualization of micro and macrobubbles tissue heating; assessment of catheter contact with cardiac tissues. Recently, also the feasibility of the integration of electroanatomical mapping (EAM) and intracardiac echocardiography has been demonstrated, combining accurate real time anatomical information with electroanatomical data. As a matter of fact, different techniques and ablation strategies have been developed throughout the years. In the setting of balloon-based ablation systems, recently adopted by an increasing number of centers, ICE might have a role in the choice of appropriate balloon size and to confirm accurate occlusion of pulmonary veins. Furthermore, in the era of minimally fluoroscopic ablation, ICE has successfully provided a contribute in reducing fluoroscopy time. The purpose of this review is to summarize the current applications of ICE in catheter based ablation strategies of atrial fibrillation, focusing-on electronically phased-array ICE.

Ablate and Pace Therapy or AV Junction Modification for Medically Refractory Atrial Fibrillation

Currently available nonpharmacological techniques for ventricular rate control in patients with drug refractory atrial fibrillation (AF) include radiofrequency ablation of the atrioventricular (AV) junction with pacemaker implantation [1–4] and modulation of AV node conduction [5–8]. The former is an already established approach with a high success rate and predictable long-term effects; it also has limitations that include a nonphysiological pattern of ventricular activation and possible risk of late sudden death [9, 10]. Modulation of the AV node conduction has been introduced more recently into clinical practice, and, although it eliminates lifetime pacemaker dependence, it is less widely accepted because of a lower acute success rate, risk of inadvertent AV block, and persistence of irregular heartbeat. Since recent randomized studies [10, 11] comparing acute and medium term outcomes of the two techniques have given contrasting results, at the present time the relative merits of the two techniques are not well defined.