br Conclusion br Conflict of interest br Introduction

Conclusion
Conflict of interest
Introduction Radiofrequency catheter ablation has been established as an effective and curative therapy for Wolff-Parkinson-White Syndrome [1–4]. Therefore, prediction of the precise location of an accessory pathway (AP) prior to the ablation procedure is of clinical importance. Several algorithms have been published to localize the AP on a surface 12-lead electrocardiogram (ECG) [5–8]. Most of them are based on analysis of delta wave morphology. However, they are somewhat complicated, and an accurate determination of the delta wave morphology is occasionally difficult. On the other hand, some algorithms based on the QRS polarity have been reported [9,10], but their accuracy is still limited. The aims of this study were to develop a simple and highly accurate algorithm for localizing APs using only the R/S ratio, and to test the accuracy of the algorithm prospectively.
Material and methods
Results
Discussion
Conclusion
Conflict of interest
Introduction Ablation on the mitral annulus is an important procedure for the non-pharmacological treatment of atrial fibrillation. However, it is known to cause injury of the left circumflex coronary artery (Lcx) [1,2]. In the present study, we assessed the anatomical relationships among the posterior mitral annulus (PMA), coronary arteries, coronary sinus (CS), and pulmonary veins in autopsied hearts, and attempted to identify safe ablation sites on the PMA.
Materials and methods The Lcx from 50 adult autopsy xpo 1 specimens were examined and divided into 3 types according to its final branch: obtuse marginal branch (OM) type, posterolateral branch (PL) type, and posterior descending branch (PD) type. To distinguish between the OM and PL types, we examined the Lcx in the front view of the left anterior descending artery where the ventricular septum and mitral annulus were present vertical to the investigator′s eyes. If the final branch was visible in this view, it was defined as the OM type. If the PD originated from the Lcx, it was defined as the PD type. We measured the lengths from the anterior commissure to the following points on the PMA (Fig. 1): (a) the end of the Lcx (length-a); (b) the right coronary artery (length-b); and (c) the catheter ablation point (length-c), to which the shortest line was drawn from the left inferior pulmonary vein in the posterolateral mitral isthmus [3]. Each point was expressed as a percentage of each length to the total length of the PMA (length-PMA). The space between (a) and (b) was defined as the no-coronary area. Distances from the Lcx to the PMA and CS were measured vertically at the catheter ablation point (Fig. 1). The institutional ethical committee approved this study. The values are expressed as mean±SD.
Discussion To our knowledge, this is the first report that examines the use of the no-coronary area on the PMA as a potential safe ablation site. As coronary arteries cannot be identified during either catheter intervention or surgery for atrial fibrillation, elucidating the location of the no-coronary area on the PMA would be helpful. Although catheter ablation can be performed under the guidance of three-dimensional computed tomography, information about the Lcx is occasionally unclear. In the present study, we noted that the no-coronary area was located between 60% and 75% for the PL type, which is approximately 1.5cm to the right of the catheter ablation point. In the surgeon′s viewpoint, it is located around the gap between P2 and P3 of the mitral leaflet. Catheter ablation from the CS to the PMA is associated with a risk of Lcx injury as the distance between the CS and Lcx is only 4.6mm. Thus, the current finding is consistent with those of previous studies that indicated a significant risk of Lcx injury in such cases [1].
Conclusion
Conflict of interest