Yoshinari Goseki

Electrophysiologic Effects of Selective Right versus Left Atrial Linear Lesions in a Canine Model of Chronic Atrial Fibrillation

Mapping of Atrial Fibrillation. Introduction: Long linear lesions have been shown to eliminate atrial fibrillation in animal models, but little is known about the electrophysiologic response in one atrium to lesions in the contralateral atrium.

Novel Catheter Technology for Ablative Cure of Atrial Fibrillation

Atrial ~brillation (AF) is the most common sustained arrhythmia in clinical practice. It affects approximately 2,000,000 Americans with 160,000 new cases per year. Drug therapy can be associated with a number of untoward effects such as proarrhythmia, long term inef~cacy and even an increase in mortality, especially in those with impaired ventricular function [1,2]. Catheter ablation of the atrioventricular node with pacemaker implantation [3,4], or modi~cation of the AV node without pacer implantation [5,6] can be useful to facilitate ventricular rate control, but thromboembolic risk is unchanged and atrial systole is not restored. Given the limitations of medical therapy, repeated cardioversions and atrioventricular conduction ablation, an approach that cures atrial ~brillation would be highly desirable. At the present time, catheter-based cure of atrial ~brillation must be considered highly investigational. Nevertheless, because the clinical need for better therapy of atrial ~brillation is so vast, there are a number of on-going efforts to develop devices and techniques for atrial ablation in order to effectively restore sinus rhythm and atrial mechanical contraction. Do we need a cure for atrial ~brillation? Certainly, given the problems with drug treatment and the impact on quality of life, a cure would be highly desirable, and efforts to create such a cure well rewarded. In the history of electrophysiologic intervention, there are many examples in which a cycle of clinical science and new interventional techniques has been demonstrated. That is, we start with a given hypothesis of arrhythmia mechanism or substrate, we intervene to alter what we believe to be the substrate (with surgery, or with catheter-based techniques), in the process of intervention we have an opportunity to garner further, more accurate insights into mechanism and substrate and to develop subsets of what we has thought was a single disorder, and this in turn allows us to develop better interventional tools and techniques. For example, all regular narrow complex tachycardias used to go by the moniker of “PAT.” First with surgery, and then with catheter-based techniques, we came to be able to discern that “PAT” may actually be one of several speci~c arrhythmia substrates such as WPW, AV nodal reentry, etc. In the era of catheter ablation, we can now even describe three or more types of AV nodal reentry. So, too, our ability to intervene on patients with atrial ~brillation has just begun to allow us to develop more detailed descriptions of mechanism. “Atrial ~brillation” as such may come to be recognized as the common surface manifestation of multiple potential mechanisms. This will allow us to develop tools and techniques that are more directly targeted to a given mechanism. In the case of atrial ~brillation this will be particularly important, since if one considers the current “gold standard” for curative intervention to be the extensive lesions produced during the Cox surgical maze operation, then recognition of AF mechanisms that require a less extensive lesion set would be highly desirable. Recently, it has come to be understood that the initiating event in many cases of AF is a “focal trigger” arising in the vast majority of cases from within one of the pulmonary veins [7]. The purpose of the present paper is to brie_y describe early progress towards the development of a novel technology addressing this particular class of AF mechanism.

Electrocardiographic Analysis of Ectopic Atrial Activity Obscured by Ventricular Repolarization: P Wave Isolation Using an Automatic 62-Lead QRST Subtraction Algorithm

62‐Lead QRST Subtraction Algorithm. Introduction: Atrial activity on the surface ECG during premature beats and supraventricular arrhythmias frequently is obscured by the superimposed QRST complex of the previous cardiac cycle. This study examines the performance of a newly developed automatic QRST subtraction algorithm to isolate ectopic P waves from the preceding T‐U wave.

Automated QRST subtraction algorithm for analysis of T wave obscured ectopic atrial beats

An automatic QRST subtraction algorithm to isolate ectopic P waves from the superimposed TU wave in the surface ECG was developed. QRST removal was accomplished using an adaptive template constructed from averaged QRST complexes. Sixty-two-lead body surface integral maps of obscured and nonobscured paced P waves were computed and visually and mathematically compared using correlation coefficients.