Moussa Mansour

Assessment of pulmonary vein anatomic variability by magnetic resonance imaging: implications for catheter ablation techniques for atrial fibrillation.

Introduction: Pulmonary vein (PV) isolation for atrial fibrillation (AF) currently is performed using either an ostial or an extra‐ostial approach. The objective of this study was to analyze by three‐dimensional (3D) magnetic resonance angiography (MRA) the anatomy of the PVs in order to detect structural variability that would impact the choice of ablation approach.

Three‐Dimensional Anatomy of the Left Atrium by Magnetic Resonance Angiography: Implications for Catheter Ablation for Atrial Fibrillation

Background: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug‐refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported.

Left atrial appendage dimensions predict the risk of stroke/TIA in patients with atrial fibrillation.

Risk of Stroke/TIA in Patients With Atrial Fibrillation. Introduction: Most strokes in patients with atrial fibrillation (AF) arise from thrombus formation in left atrial appendage (LAA). Our aim was to identify LAA features associated with a higher stroke risk in patients with AF using magnetic resonance imaging and angiography (MRI/MRA).

Left atrial wall thickness variability measured by CT scans in patients undergoing pulmonary vein isolation

Left Atrial Wall Thickness Variability Measured by CT Scans.u2002Introduction: Successful catheter ablation of atrial fibrillation (AF) requires the creation of transmural lesions in the left atrium (LA). In addition, cardiac perforation is more likely to occur in areas of thin walls. The LA wall thickness is thus relevant both for procedural efficacy and safety. This study sought to evaluate the regional LA wall thickness in patients with AF.

Multi-sensor esophageal temperature probe used during radiofrequency ablation for atrial fibrillation is associated with increased intraluminal temperature detection and increased risk of esophageal injury compared to single-sensor probe.

Radiofrequency (RF) ablation in the posterior left atrium has risk of thermal injury to the adjacent esophagus. Increased intraluminal esophageal temperature has been correlated with risk of esophageal injury. The objective of this study was to compare esophageal temperature monitoring (ETM) using a multi‐sensor temperature probe with 12 sensors to a single‐sensor probe during catheter ablation for atrial fibrillation (AF).

Impact of Periprocedural Colchicine on Postprocedural Management in Patients Undergoing a Left Atrial Appendage Ligation Using LARIAT.

Left atrial appendage (LAA) can be effectively and safely excluded using a novel percutaneous LARIAT ligation system. However, due to pericardial catheter manipulation and LAA ligation and subsequent necrosis, postprocedural course is complicated by pericarditis. We intended to evaluate the preprocedural use of colchicine on the incidence of postprocedural pericardial complications.

Long-Term Outcome of Patients With Idiopathic Ventricular Fibrillation: A Meta-Analysis.

The long‐term outcome of the patients with idiopathic ventricular fibrillation (IVF) is not well known.

Learning While Burning

Until recently, the most widely accepted mechanism of atrial fibrillation (AF) was the multiple wavelet hypothesis described by Moe and Abildskov1 in 1959. According to this hypothesis, AF is a self-sustaining process consisting of multiple wavelets that move randomly throughout the atria, independent of the initiating event. Experimental support for this hypothesis was provided in 1985 by Allessie et al.,2 who estimated that four to six wavelets were critical for maintenance of AF in the canine heart. This hypothesis was further strengthened by the clinical observation that AF could be cured by the placement of surgical or cryolesions (MAZE) to compartmentalize the atria into regions presumably unable to sustain the multiple wavelets.3 The discovery by Haissaguerre et al.4 in 1998 that focal ablation could eliminate AF represented a major therapeutic advance. A more important consequence of that finding was to revive the concept of AF as the result of a rapidly firing focus. This theory was described in 1925 by Sir Thomas Lewis,5 who observed that “. . . fibrillation, like flutter, may also on occasion be terminated in the auricle by cold or pressure very locally applied.” Additional support for this alternative view came later from Scherf et al.,6,7 who used local application of aconitine to induce AF and then demonstrated that obliteration of the site of aconitine application resulted in AF termination. However, this concept was not initially accepted by electrophysiologists, perhaps due to the limited investigative methodologies available at that time, which prevented exhaustive characterization of electrical waves propagation. With the development of high-resolution mapping techniques such as optical mapping, this task became achievable. A series of studies from the laboratory of Jalife et al.8-12 described vortex-like reentry (rotors) around minuscule cores, with high-frequency periodic activity in the posterior left atrium and the pulmonary veins ostia. Rapid and successive electrical impulses emanating from these rotors propagate throughout the atria and interact with functional and/or anatomic obstacles leading to fragmentation and wavelets formation. This “fibrillatory conduction” results in the seemingly random electrical activity that characterizes AF. The article by Scharf et al.13 in this issue of the Journal describes the acute outcome of left atrial ablation for AF. Although it was not the aim of this investigation to study the mechanisms of AF, some of its findings have important

Feasibility of Transseptal Puncture Using a Nonfluoroscopic Catheter Tracking System.

Radiation exposure in the electrophysiology lab is a major occupational hazard to the electrophysiologists. A catheter localization system (MediGuide Technology, St. Jude Medical Inc., St. Paul, MN, USA) allows the integration of electroanatomical mapping and x‐ray imaging, and has been shown to be effective in reducing radiation exposure during several electrophysiological procedures. We intended to evaluate the feasibility of this catheter tracking system to guide transseptal (TS) access.

Comparison of Electroanatomical Mapping Systems: Accuracy in Left Atrial Mapping

Current 3D mapping systems have difficulty rendering complex cardiac structures. Different electroanatomical mapping software has been recently developed which uses a mathematical algorithm to improve interpolation between mapped points and delineation of closely spaced structures. This study tested the feasibility and accuracy of this software in comparison to traditional software.