Yoshimasa Murakami

Idiopathic Ventricular Arrhythmias Originating from the Papillary Muscles in the Left Ventricle: Prevalence, Electrocardiographic and Electrophysiological Characteristics, and Results of the Radiofrequency Catheter Ablation

Idiopathic VAs Originating from the LV Papillary Muscles.u2002Introduction: Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular (LV) papillary muscles (PAMs). This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and results of catheter ablation of these VAs, and compared them with other LV VAs.

Idiopathic Focal Ventricular Arrhythmias Originating from the Anterior Papillary Muscle in the Left Ventricle

Introduction: Focal ventricular arrhythmias (VAs) have been reported to arise from the posterior papillary muscle in the left ventricle (LV). We report a distinct subgroup of idiopathic VAs arising from the anterior papillary muscle (APM) in the LV.

Idiopathic Left Ventricular Arrhythmias Originating Adjacent to the Left Aortic Sinus of Valsalva: Electrophysiological Rationale for the Surface Electrocardiogram

IVT Arising Adjacent to the Left Sinus of Valsalva. Background: Idiopathic ventricular arrhythmias (VAs) may be amenable to catheter ablation within or adjacent to the left sinus of Valsalva (LSOV). However, features that discriminate these sites have not been defined. The purpose of this study was to determine the electrocardiographic and electrophysiological features of VAs originating within or adjacent to the LSOV.

Does RV Lead Positioning Provide Additional Benefit to Cardiac Resynchronization Therapy in Patients with Advanced Heart Failure

Background and Objectives: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA).

Electrophysiologic characteristics of atrial tachycardia originating from the right pulmonary veins or posterior right atrium: Double Potentials obtained from the posterior wall of the right atrium Can be useful to Predict foci of atrial tachycardia in the right pulmonary veins or posterior right atrium

Introduction: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs.

Non‐Pulmonary Vein Epicardial Foci of Atrial Fibrillation Identified in the Left Atrium after Pulmonary Vein Isolation

Background: Pulmonary vein (PV) isolation (PVI) has been demonstrated to be an effective technique for curing atrial fibrillation (AF). AF foci that cannot be isolated by PVI (non‐PV foci) can become the cause of AF recurrence. The purpose of this study was to investigate the characteristics of non‐PV AF foci.

Premature Ventricular Contractions Arising from the Intramural Ventricular Septum

A 68‐year‐old man with symptomatic idiopathic premature ventricular contractions (PVCs) underwent electrophysiological testing. Radiofrequency catheter ablation was unsuccessful at the earliest endocardial ventricular activation site in the left coronary cusp. Epicardial mapping via the cardiac veins was then performed. Balloon‐occluded coronary sinus venography revealed the small branches of the anterior interventricular vein. Mapping with a microcatheter revealed the earliest ventricular activation and perfect pace map at the distal portion of the septal perforating branch, suggesting an intramural ventricular septal PVC origin. Catheter ablation was abandoned because of the inaccessibility of the ablation catheter to that site via the venous system.

Adenosine can also improve the conduction between the superior vena cava and right atrium after isolation.

A 64‐year‐old man with atrial tachycardia (AT) 3 years after a superior vena cava (SVC) isolation for atrial fibrillation underwent electrophysiologic testing. SVC mapping with a basket catheter revealed a more frequent activation in the SVC than in either of the atria during the AT and consequently the recovered conduction between the SVC and right atrium. The conduction improved from 3 or 4–1 conduction to 2–1 conduction after adenosine was administered. Ectopic firing in the SVC persisted even after restoration of sinus rhythm by the successful SVC isolation, which was confirmed by adenosine.

A Very Narrow Preexisting Isthmus in a Case with Typical Atrial Flutter

A 61‐year‐old woman with typical atrial flutter underwent an electrophysiologic study and radiofrequency catheter ablation. The electroanatomic mapping revealed two contiguous lines of distinct double potentials (DPs) extending anteriorly/posteriorly from the coronary sinus ostium to the inferior vena cava (IVC) border. A large part of the anterior line of the DPs was close and parallel to the tricuspid annulus (TA). An initial discrete radiofrequency application at the very narrow preexisting isthmus between the TA and anterior line of the DPs completed the IVC‐TA isthmus conduction block.

Detour Conduction Can Mimic Complete Conduction Block at the Cavo‐Tricuspid Isthmus

A 54‐year‐old man with typical atrial flutter underwent linear ablation at the cavo‐tricuspid isthmus. Though standard tricuspid annulus (TA) mapping and differential pacing suggested complete isthmus conduction block, electroanatomic mapping revealed that detoured conduction through a residual conduction gap around the inferior vena cava far from the TA mimicked complete conduction block. Though the double potential interval along the block line was not long enough to guarantee a complete line of block after eliminating the conduction gap, electroanatomic remapping accurately confirmed a complete block line, suggesting electroanatomic mapping may be the most reliable method to confirm complete isthmus conduction block.