Gábor Bencsik

Esophageal damage during radiofrequency ablation of atrial fibrillation: impact of energy settings, lesion sets, and esophageal visualization.

Introduction: Atrioesophageal fistula is an uncommon but often lethal complication of atrial fibrillation (AF) ablation. The purpose of our study was to prospectively investigate the incidence of esophageal ulcerations (ESUL) as well as the impact of energy settings, radiofrequency lesion sets, and direct visualization of the esophagus on esophageal wall injury.

Identification of a high-risk population for esophageal injury during radiofrequency catheter ablation of atrial fibrillation: procedural and anatomical considerations.

BACKGROUND Atrioesophageal fistula is an uncommon but life-threatening complication of atrial fibrillation (AF) ablation. Esophageal ulcerations (ESUL) have been proposed to be potential precursor lesions. OBJECTIVE The purpose of our study was to prospectively investigate the incidence of ESUL in a large patient population undergoing radiofrequency catheter ablation (RFA). Additionally, we aimed to link demographic data and lesion sets with anatomical information given by multislice computed tomography imaging and to correlate these data with the development of ESUL. METHODS This study included 267 patients and consecutively screened all individuals for evidence of ESUL 24 h after RFA of AF by endoscopy of the esophagus. A standardized ablation approach using a 25-W energy maximum at the posterior left atrial (LA) wall without esophagus visualization, temperature monitoring, or intracardiac ultrasound was performed. RESULTS In total, we found 2.2% of patients (6 of 267) presenting with ESUL. Parameters exposing a specific patient to risk of developing ESUL in univariate analysis were persistent AF (5 of 95, P = .023), additional lines performed (roofline: 6 of 114, P = .006; LA isthmus: 4 of 49, P = .011; coronary sinus: 5 of 66, P = .004), and LA enlargement (P = .001) leading to sandwiching of the esophagus between the LA and thoracic spine. Multivariate analysis revealed LA-to-esophagus distance as the only significant risk factor. CONCLUSION This study is the first to link anatomical information and procedural considerations to the development of ESUL in radiofrequency ablation for AF. Furthermore, it reveals the correlation and individual impact of these factors. Not a single patient with pulmonary vein isolation alone developed ESUL.

Acute development of gastroesophageal reflux after radiofrequency catheter ablation of atrial fibrillation

BACKGROUND Induction of gastroesophageal reflux after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) may have an impact on the progression of esophageal injury. OBJECTIVE The purpose of this study was to assess the acute effect of RFCA on distal esophageal acidity using leadless pH-metry capsules. METHODS A total of 31 patients (27 male and 4 female; 25 with paroxysmal AF) who underwent RFCA and esophagoscopy 24 hours before and after ablation were assessed for reflux and esophageal lesions. A leadless pH-metry capsule was inserted into the lower esophagus to screen for pH changes, number and duration of refluxes, and the DeMeester score (a standardized measure of acidity and reflux). No patient had a history of reflux or was taking proton pump inhibitors within 4 weeks before and 24 hours after ablation. RESULTS Five patients (16.1%) who presented with asymptomatic reflux prior to ablation were excluded from further examination. Of the remaining 26 patients, 5 (19.2%) demonstrated a significant pathologic increase in DeMeester score after ablation. No statistical differences in baseline parameters, method of sedation, ablation approach, and total energy delivered on the posterior wall were observed between patients with and those without a pathologic DeMeester score. One patient with asymptomatic reflux prior to ablation developed esophageal ulceration. CONCLUSION A significant number of patients undergoing RFCA of AF develop pathologic acid reflux after ablation. In addition, a subgroup of patients has a preexisting condition of asymptomatic reflux prior to ablation. This finding may explain a potential mechanism for progression of esophageal injury to atrio-esophageal fistulas in patients undergoing RFCA.

Electrochemical grafting of poly(3,4-ethylenedioxythiophene) into a titanium dioxide nanotube host network.

This study focuses on electrodeposition for infiltrating in situ a conducting polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT) into a host titanium dioxide (TiO(2)) nanotube array (NTA) framework. The TiO(2) NTA was electrosynthesized on titanium foil in turn by anodization in a fluoride-containing medium. The PEDOT layer was electrografted into the TiO(2) NTA framework using a two-step potentiostatic growth protocol in acetonitrile containing supporting electrolyte. The nanoscopic features of oligomer/polymer infiltration and deposition in the NTA interstitial voids were monitored by field-emission scanning electron microscopy. Systematic changes in the nanotube inner diameter and the wall thickness afforded insights into the evolution of the TiO(2)NTA/PEDOT hybrid assembly. This assembly was subsequently characterized by UV-visible diffuse reflectance, cyclic voltammetry, and photoelectrochemical measurements. These data serve as a prelude to further use of these hybrids in heterojunction solar cells.

Acute effects of complex fractionated atrial electrogram ablation on dominant frequency and regulatory index for the fibrillatory process

AIMS The purpose of our study was to determine the acute effects of complex fractionated electrograms (CFAE) ablation guided by automated detection on dominant frequency (DF) and regulatory index (RI) for the fibrillatory process. METHODS AND RESULTS The study included 41 patients (21 paroxysmal and 20 persistent) referred for catheter ablation of atrial fibrillation (AF). Our ablation strategy included pulmonary vein isolation (PVI) as first step, CFAE ablation as second step, roof line ablation as next, and mitral isthmus ablation as last step. On the CFAE map, we were targeting only points outside the previous PVI lines. Simultaneously, we evaluated DF and RI changes in the coronary sinus after each step of ablation. The termination rate by CFAE ablation was low (12.5% in paroxysmal and 10% in persistent AF). Changes in DF and RI after CFAE ablation were not significant (<0.25 Hz and max. 0.02 increase for RI) compared with other ablation steps. Pulmonary vein isolation, roof line, and mitral isthmus ablation resulted in significant changes in DF and RI. CONCLUSION On the basis of our results, CFAE ablation guided by a dedicated software algorithm and performed after standard PVI without CFAE remapping does not influence the fibrillatory process significantly. Application of a modified algorithm with different settings warrants further investigations.

Ablation of Posteroseptal and Left Posterior Accessory Pathways Guided by Left Atrium–Coronary Sinus Musculature Activation Sequence

Introduction: While some posteroseptal and left posterior accessory pathways (APs) can be ablated on the tricuspid annulus or within the coronary venous system, others require a left‐sided approach. “Fragmented” or double potentials are frequently recorded in the coronary sinus (CS), with a smaller, blunt component from left atrial (LA) myocardium, and a larger, sharp signal from the CS musculature.

Randomized Trial of Intracardiac Echocardiography During Cavotricuspid Isthmus Ablation

Randomized Trial of ICE During CTI Ablation. Introduction: Despite a high success rate, radio‐frequency ablation (RFA) of the cavotricuspid isthmus (CTI) can be unusually challenging in some cases. We postulated that visualization of the CTI with intracardiac echocardiography (ICE) could maximize the succes rate, decrease the procedure and ablation time, and minimize the radiation exposure.

Photosynthetic reaction centers/ITO hybrid nanostructure

Photosynthetic reaction center proteins purified from Rhodobacter sphaeroides purple bacterium were deposited on the surface of indium tin oxide (ITO), a transparent conductive oxide, and the photochemical/-physical properties of the composite were investigated. The kinetics of the light induced absorption change indicated that the RC was active in the composite and there was an interaction between the protein cofactors and the ITO. The electrochromic response of the bacteriopheophytine absorption at 771 nm showed an increased electric field perturbation around this chromophore on the surface of ITO compared to the one measured in solution. This absorption change is associated with the charge-compensating relaxation events inside the protein. Similar life time, but smaller magnitude of this absorption change was measured on the surface of borosilicate glass. The light induced change in the conductivity of the composite as a function of the concentration showed the typical sigmoid saturation characteristics unlike if the photochemically inactive chlorophyll was layered on the ITO. In this later case the light induced change in the conductivity was oppositely proportional to the chlorophyll concentration due to the thermal dissipation of the excitation energy. The sensitivity of the measurement is very high; few picomole RC can change the light induced resistance of the composite.

Ventricular location of a part of the right atrial isthmus after tricuspid valve replacement for Ebstein’s anomaly: a challenge for atrial flutter ablation

We report the case of a patient with atrial flutter late after tricuspid valve replacement for Ebstein’s anomaly. Computed tomographic angiography revealed that coronary sinus ostium and part of the right atrial isthmus were located on the ventricular side of the valve ring due to the specific surgical approach in this condition. Based on the results of electroanatomic mapping and entrainment, the arrhythmia was found to be cavotricuspid isthmus dependent clockwise atrial flutter. Completion of the isthmus line required ablation lesions across the artificial valve. When these were delivered the arrhythmia terminated and isthmus block was achieved. Due to arrhythmia recurrence a redo procedure was performed which demonstrated conduction recovery in the ventricular part of the cavotricuspid isthmus. Intracardiac ultrasound-guided ablation successfully eliminated conduction across the isthmus with subsequent freedom from arrhythmia on follow up.

Intracardiac echocardiography for visualization of the Eustachian valve during radiofrequency ablation of typical atrial flutter

We performed a conventional, fluoroscopy-guided ablation of ongoing typical atrial flutter at the preferred isthmus site. Despite 150 min of procedure time (using a 4 mm, irrigated tip catheter with settings of 43°C, 40 W and …