Lack of Anticoagulant Use in Patients with Atrial Fibrillation and Increased Risk of Thromboembolic Events According to Sex: Insights from a Multicentric Brazilian Study.

Background: Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, and its presentation differs according to age and sex. Recent studies have revealed differences in AF among various demographic groups, including the Latin American population.

Objectives: To better understand potential disparities in AF prevalence and treatment strategies in the Brazilian population through data from a large multicentric prospective registry.

Characterization of Lesions Created by a Heated, Saline Irrigated Needle-Tip Catheter in the Normal and Infarcted Canine Heart.

Background: Inability to eliminate intramural arrhythmogenic substrate may lead to recurrent ventricular tachycardia after catheter ablation. The aim of the present study was to evaluate intramural and full thickness lesion formation using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter, compared with a conventional ablation catheter in normal and infarcted myocardium.

Methods: Twenty-two adult mongrel dogs (30-40 kg, 15 normal and 7 myocardial infarct group) were studied.

Novel Techniques in Epilepsy Management: Venous Pacing and Capture of Electrical Activity in the Primate Cortex.

Objective: Pharmacotherapy for epilepsy is limited with 30% of patients refractory to this approach of suppressing seizures. Current surgical options are invasive and carry significant morbidities including infection, bleeding, and the potential for deleterious neurocognitive effects. As a result, there is a burgeoning need for innovation to develop safer and efficacious interventions.

Prevention of Coagulum Formation With Simultaneous Charge Delivery in Radiofrequency Ablation: A Canine Model.

Objectives: This study reports on a novel method to prevent coagulum formation by continuously delivering a negative charge to the catheter tip to repel negatively charged fibrinogen molecules during RF ablation.

Background: Radiofrequency (RF) ablation for cardiac arrhythmias is associated with a 70% incidence of coagulum formation on the catheter tip during ablation and a 10% incidence of thromboembolic events. Catheter tip thrombus can impede RF energy to the tissue, reducing efficacy and increasing procedure times.

Impact of atrial fibrillation ablation on left ventricular filling pressure and left atrial remodeling.

Background: Left ventricular (LV) diastolic dysfunction is associated with new-onset atrial fibrillation (AF), and the estimation of elevated LV filling pressures by E/e' ratio is related to worse outcomes in patients with AF. However, it is unknown if restoring sinus rhythm reverses this process.

Objective: To evaluate the impact of AF ablation on estimated LV filling pressure.

Advances in radiofrequency ablation of the cerebral cortex in primates using the venous system: Improvements for treating epilepsy with catheter ablation technology.

Background: Pharmacology frequently fails for the treatment of epilepsy. Although surgical techniques are effective, these procedures are highly invasive. We describe feasibility and efficacy of minimally invasive mapping and ablation for the treatment of epilepsy.

Sudden cardiac arrest in general anesthesia as the first manifestation of anomalous origin of the left coronary artery.

Background And Objectives: This case report describes a rare and potentially fatal condition associated with anesthesia administration. Our aim was to discuss the causes of sudden cardiac arrest during the perioperative period in apparently healthy patients and the pathophysiology of anomalous origin of the coronary arteries as a cause of sudden cardiac arrest.

Case Report: Female patient, 44 years old, with no previous symptoms of heart disease or arrhythmias, had a sudden cardiac arrest during general anesthesia in two different situations.

Luminal esophageal temperature monitoring with a deflectable esophageal temperature probe and intracardiac echocardiography may reduce esophageal injury during atrial fibrillation ablation procedures: results of a pilot study.

Background: Luminal esophageal temperature (LET) monitoring is one strategy to minimize esophageal injury during atrial fibrillation ablation procedures. However, esophageal ulceration and fistulas have been reported despite adequate LET monitoring. The objective of this study was to assess a novel approach to LET monitoring with a deflectable LET probe on the rate of esophageal injury in patients undergoing atrial fibrillation ablation.

Simultaneous epicardial and endocardial substrate mapping and radiofrequency catheter ablation as first-line treatment for ventricular tachycardia and frequent ICD shocks in chronic chagasic cardiomyopathy.

Background And Aims: Slow conduction scarred areas are related with ventricular tachycardia (VT) arrhythmogenesis in nonischemic cardiomyopathy. The purpose of this study was to characterize the substrate in both epicardial and endocardial surfaces of the left ventricle and to evaluate the effectiveness of substrate mapping and ablation for VT in Chagas cardiomyopathy.

Methods And Results: Seventeen patients were evaluated prospectively using a simultaneous epicardial and endocardial electroanatomical substrate mapping and ablation.

Synchronous ventricular pacing without crossing the tricuspid valve or entering the coronary sinus--preliminary results.

Background: Right ventricular apical (RVA) pacing promotes tricuspid regurgitation (TR), electromechanical dyssynchrony, and ventricular dysfunction. We tested a novel intramyocardial bipolar lead to assess whether stimulation of the atrioventricular septum (AVS) produces synchronous ventricular activation without crossing the tricuspid valve (TV).

Methods: A lead with an active external helix and central pin was placed on the AVS and the RVA in three dogs.

Distortion of right superior pulmonary vein anatomy by balloon catheters as a contributor to phrenic nerve injury.

Introduction: Cryothermal, HIFU, and laser catheter-based balloon technologies have been developed to simplify ablation for AF. Initial enthusiasm for their widespread use has been dampened by phrenic nerve (PN) injury. The interaction between PN and pulmonary vein (PV) geometry contributing to PN injury is unclear.

Catecholaminergic polymorphic ventricular tachycardia: a current overview.

Catecholaminergic polymorphic ventricular tachycardia occurs in healthy children and young adults causing syncope and sudden cardiac death. This is a familial disease, which affect de novo mutation in 50% of the cases. At least two causative genes have been described to be localized in the chromosome 1; mutation of the ryanodine receptor gene and calsequestrin gene.

Utilization of retrograde right bundle branch block to differentiate atrioventricular nodal from accessory pathway conduction.

Introduction: Defining whether retrograde ventriculoatrial (V-A) conduction is via the AV node (AVN) or an accessory pathway (AP) is important during ablation procedures for supraventricular tachycardia (SVT). With the introduction of ventricular extrastimuli (VEST), retrograde right bundle branch block (RBBB) may occur, prolonging the V-H interval, but only when AV node conduction is present. We hypothesized that when AP conduction was present, the V-A interval would increase less than the V-H interval, whereas with retrograde nodal conduction, the V-A interval would increase at least as much as the V-H interval.

New generation of electro-anatomic mapping: full intracardiac ultrasound image integration.

Surrogate electro-anatomic-derived geometries are used as the three-dimensional (3D) basis for mapping of cardiac arrhythmias. While merged computed tomography (CT) imaging may provide stellar pulmonary vein (PV) and left atrial (LA) anatomy, the applied scans must be obtained prior to ablation, and may not reflect physiologic conditions at the time of intervention. Patient-specific, ultrasound-derived 3D imaging has been developed as an alternative basis for new generation electro-anatomic mapping.

Successful radiofrequency ablation of the cerebral cortex in pigs using the venous system: possible implications for treating CNS disorders.

Background: When pharmacotherapy for epilepsy fails, surgical options, although efficacious, are highly invasive. We explored whether ablation of the cerebral cortex can be performed utilizing the cerebral venous system.

Methods: Mapping and radiofrequency ablation was performed via the venous system in two pigs.

Three-dimensional ultrasound for image-guided mapping and intervention: methods, quantitative validation, and clinical feasibility of a novel multimodality image mapping system.

Background: Multiple factors create discrepancies between electroanatomic maps and merged, preacquired computed tomographic images used in guiding atrial fibrillation ablation. Therefore, a Carto-based 3D ultrasound image system (Biosense Webster Inc) was validated in an animal model and tested in 15 atrial fibrillation patients.

Methods And Results: Twelve dogs underwent evaluation using a newly developed Carto-based 3D ultrasound system.

Mechanism of tissue heating during high intensity focused ultrasound pulmonary vein isolation: implications for atrial fibrillation ablation efficacy and phrenic nerve protection.

Introduction: The purpose of this study was to examine tissue temperatures around pulmonary veins (PVs) during high intensity focused ultrasound (HIFU) balloon ablation for atrial fibrillation. The thermodynamics and extent of PV and phrenic nerve (PN) heating during HIFU ablation have not been established.

Methods And Results: Tissue temperatures were recorded from epicardial thermocouples at right superior (RS) PV orifice and PN in eight dogs undergoing 51 RSPV HIFU ablations (40 seconds, 40 W).

A systematical analysis of in vivo contact forces on virtual catheter tip/tissue surface contact during cardiac mapping and intervention.

Introduction: While catheter tip/tissue contact has been shown to be an important determinant of ablative lesions in in vitro studies, the impact of contact on the outcomes of mapping and ablation in the intact heart has not been evaluated.

Methods And Results: Twelve dogs underwent atrial ablation guided by the Senesitrade mark robotic catheter remote control system. After intracardiac ultrasound (ICE) validation of contact force measured by an in-line mechanical sensor, the relationship between contact force and individual lesion formation was established during irrigated-tipped ablation (flow 17 mL/sec) at 15 watts for 30 seconds.