Remote magnetic navigation to guide endocardial and epicardial catheter mapping of scar-related ventricular tachycardia.

Background: The present study examines the safety and feasibility of using a remote magnetic navigation system to perform endocardial and epicardial substrate-based mapping and radiofrequency ablation in patients with scar-related ventricular tachycardia (VT).

Methods And Results: Using the magnetic navigation system, we performed 27 procedures on 24 consecutive patients with a history of VT related to myocardial infarction, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, or sarcoidosis. Electroanatomic mapping of the left ventricular, right ventricular, and ventricular epicardial surfaces was constructed in 24, 10, and 12 patients, respectively.

Factors affecting error in integration of electroanatomic mapping with CT and MR imaging during catheter ablation of atrial fibrillation.

Objective: Integration of 3-D electroanatomic mapping with Computed Tomographic (CT) and Magnetic Resonance (MR) imaging is gaining acceptance to facilitate catheter ablation of atrial fibrillation. This is critically dependent on accurate integration of electroanatomic maps with CT or MR images. We sought to examine the effect of patient- and technique-related factors on integration accuracy of electroanatomic mapping with CT and MR imaging of the left atrium.

Ablation of left ventricular epicardial outflow tract tachycardia from the distal great cardiac vein.

Objectives: The purpose of this study was to examine the feasibility and safety of ablation of idiopathic outflow tract ventricular tachycardia (OTVT) from the distal ramifications of the coronary sinus (CS).

Background: A significant minority of patients presenting with idiopathic OTVT have an epicardial focus, the standard approach to which involves ablation from within one of the aortic valve cusps (AVCs). We describe the successful ablation of idiopathic epicardial OTVT from within the CS in the distal great cardiac vein (GCV).

What is the most appropriate energy source for aortic cusp ablation? A comparison of standard RF, cooled-tip RF and cryothermal ablation.

Background: Certain tachycardias can be eliminated by catheter ablation from within the base of the aortic valve (AV) cusps but the high blood flow and proximity to the coronary arteries create unique challenges. Standard radiofrequency (RF) energy, cooled-tip RF energy or cryothermal energy were compared to determine the optimal ablation modality.

Materials And Methods: Experiments were conducted using adult swine or goats (15 animals).

Implantation of bilateral carotid artery filters to allow safe removal of left atrial thrombus during ablation of atrial fibrillation.

Left atrial clot formation is a feared complication of catheter ablation for atrial fibrillation. We report a case of left atrial thrombus that formed around the circular mapping catheter before the delivery of RF. Successful retrieval of the clot was obtained by withdrawing the catheters while protecting the anterior cerebral circulation by positioning temporary carotid artery filters.

Integration of cardiac magnetic resonance imaging with three-dimensional electroanatomic mapping to guide left ventricular catheter manipulation: feasibility in a porcine model of healed myocardial infarction.

Objectives: In a series of in vitro and in vivo experiments, we evaluated the feasibility of integrating three-dimensional (3D) magnetic resonance imaging (MRI) and electroanatomic mapping (EAM) data to guide real-time left ventricular (LV) catheter manipulation.

Background: Substrate-based catheter ablation of post-myocardial infarction ventricular tachycardia requires delineation of the scarred myocardium, typically using an EAM system. Cardiac MRI might facilitate this procedure by localizing this myocardial scar.

Left atrial-esophageal fistula following radiofrequency catheter ablation of atrial fibrillation.

This report describes a fatal case of left atrial-esophageal fistula occurring in a 72-year-old man after a radiofrequency catheter ablation of paroxysmal atrial fibrillation. Catheter ablation was performed around the pulmonary vein using an 8-mm-tip electrode (60 W or 55 degrees C) guided by a 25-mm circular catheter. On day 22 of follow-up, the patient presented with seizures followed by hematemesis due to left atrial-esophageal fistula.

Nonsurgical transthoracic epicardial approach in patients with ventricular tachycardia and previous cardiac surgery.

Introduction: The subxyphoid pericardial mapping approach can be used to facilitate catheter ablation of postmyocardial-infarction ventricular tachycardia (post-MI VT), but the presence of dense adhesions is thought to preclude this approach in patients who have previously undergone open-chest cardiac surgery.

Aims Of The Study: This study reports the first use of a nonsurgical transthoracic epicardial approach in patients with scar-related VT and previous cardiac surgery.

Methods: Five patients with a mean age of 67 +/- 10 years, left ventricular ejection fraction (LVEF) of 40 +/- 4.

Catheter ablation of ventricular epicardial tissue: a comparison of standard and cooled-tip radiofrequency energy.

Background: Transthoracic epicardial catheter ablation is an emerging catheter ablation strategy being used clinically at increasing frequency. However, the efficacy of standard RF ablation on the epicardial surface of the heart is hindered by (1) the lack of convective cooling of the ablation electrode and (2) the varying presence of epicardial adipose tissue interposed between the ablation electrode and the target site. This experimental animal study examines the biophysical characteristics of radiofrequency (RF) ablation lesions generated by either standard or cooled-tip ablation of the ventricular epicardium.

Pulmonary veins isolation to treat patients with refractory paroxysmal atrial fibrillation: clinical results after a single procedure.

Objective: The purpose of this study was to access the clinical outcome of patients submitted to a single procedure of radiofrequency pulmonary veins (PV) isolation to treat refractory paroxysmal atrial fibrillation (AF).

Methods: This study included 49 consecutive patients (36 male; mean age 54+/-10 years old) who had frequent symptomatic paroxysmal AF refractory to at least three antiarrhythmic drugs. We used a circular decapolar catheter for mapping PVs - left atrial connections and a 4-mm distal tip catheter for ablation (30 W and 50 C), aiming to achieve electrical isolation of 3 -4 PVs.

Intrapericardial echocardiography: a novel catheter-based approach to cardiac imaging.

Background: Transvascular catheter-based intracardiac echocardiography has been successfully used to help guide catheter ablation and electrophysiologic procedures. It has recently been demonstrated that catheters can be safely placed into the pericardial space to allow for epicardial cardiac mapping and ablation. We evaluated the feasibility of catheter-based intrapericardial echocardiography (IPE) during such procedures to identify cardiac structures and visualize intracardiac catheters.

Pericardial anatomy for the interventional electrophysiologist.

Investigators are beginning to exploit the pericardial space for a number of cardiovascular applications, including catheter ablation of cardiac arrhythmias, cardiovascular drug therapy, and cardiac pacing. This review explores the anatomy of the pericardial space and the anatomic variants that may be encountered in this novel approach to the heart.

Effects of radiofrequency pulses delivered in the vicinity of the coronary arteries: implications for nonsurgical transthoracic epicardial catheter ablation to treat ventricular tachycardia.

This study evaluates the effects of epicardial RF ablation on the coronary vessels in a canine model. Nonsurgical epicardial catheter ablation is a minimally invasive procedure that has proven to be efficacious for the treatment of VT. This approach is limited by concern regarding the potential adverse effects of RF ablation on the epicardial coronary arteries.

Catheter ablation of the left ventricular outflow tract tachycardia from the left atrium.

RF ablation of idiopathic left ventricular outflow tract ventricular tachycardia (LOT-VT) may imply in significant risk of damaging the proximal left main if RF pulses are being delivered from the left sinus of Valsalva or from inside an epicardial coronary vein. This report describes a new approach to control LOT-VT by means of RF catheter ablation.

New perspectives on catheter-based ablation of ventricular tachycardia complicating Chagas' disease: experimental evidence of the efficacy of near infrared lasers for catheter ablation of Chagas' VT.

Chronic Chagas' myocarditis can alter the myocardial substrate in a way that facilitates the emergence of fatal VT in a way similar to the long-term consequences of myocardial infarction. Post-myocardial infarction and Chagas' VT share many similarities: they are both macroreentrant circuits, entrainable, involving any wall segment from the endocardium to the epicardium. However, as compared to patients with post-MI VT, Chagasic patients tend to be younger and have a higher left ventricular ejection fraction.

Radiofrequency ablation of sustained ventricular tachycardia related to the mitral isthmus in Chagas' disease.

This case report describes the electrophysiological findings of a 62-year-old patient with chronic Chagas' disease and two distinct morphologies of sustained ventricular tachycardia that involved a mitral isthmus. Multiple RF applications were necessary to obtain a bidirectional conduction block in the mitral isthmus that was related to the interruption of both tachycardias. After the procedure, the patient presented massive cerebral infarction that progressed to coma and death.

Criteria for pacemaker explant in patients without a precise indication for pacemaker implantation.

Unnecessary pacemaker implantation may cause significant social and psychological consequences, the inconvenience of periodic office visits, and the expense of pulse generator replacement. Establishing adequate criteria for explantingpacemakers is crucial and has notyet been described. This study presents the results of a study protocol for explanting the pacemaker in patients without a clear indication for pacemaker implantation.