br Conflicts of interest br Acknowledgment This work was sup

Conflicts of interest
Acknowledgment This work was supported, in part, by a grant from the Experimental Research Center ELPEN (Y97/2-12-2013). The funding source had no involvement in the study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the article for publication.
Discussion The minimum His potential could be recorded near a site at the CSOS level (Fig. 1A, 3D yellow tags). The distance between the maximum and minimum His recording sites was measured as 21mm. The distance between the minimum His recording site and ablation site was only 6mm. Furthermore, the NavX system could demonstrate the activation map of the His potential and an St-H interval map of the TOK (Fig. 1). The St-H interval was shorter in the middle portion of the TOK than in the superior portion (56ms vs. 96ms). The His potential at the inferior portion of the CSOS preceded that Napabucasin cost at the apex of the TOK by 15ms. This indicated that the His bundle as well as the fast pathway could be dislocated. The 3D blue tag indicates the successful ablation site without ventriculoatrial block, which was close to those with ventriculoatrial block (Fig. 1A). Compared to the unsuccessful ablation sites with and without VA block, the successful ablation site was located at a ventricular site (Fig. 1A, bottom panel). To avoid injury to the fast pathway, the exact location of the His bundle and fast pathway should be confirmed. Tanaka et al. reported that the dislocated fast pathway was frequently and uniformly observed among various forms of AVNRT, and was probably caused by inferior displacement of the His bundle [1]. Notably, no dislocated fast pathway at the CS roof level has been documented in patients with common AVNRT [2]. We previously reported that the fast pathway was inferiorly dislocated by >10mm toward the His bundle in one-third of patients with AVNRT and appeared to be positioned deep at atrial sites. In the majority of patients with a dislocated fast pathway, the distance between the maximum and minimum His recording sites is <20mm [3]. Considering the close electrical vicinity to the His recording site, the initial RF ablation application at the slow pathway should have been performed at a more ventricular annular site in the current case. To determine the mechanism of the inferiorly dislocated His bundle and fast pathway, we investigated the anatomy of the TOK using a workstation (Ziostation ver. 2.1.7.1., Ziosoft Inc., Tokyo, Japan). Fig. 2 shows the true anatomy of the TOK and surrounding organs. In the current case, the TOK was likely to have been compressed by the aortic root and dilated CSOS. The distance between the proximal His-bundle area and CSOS was reported to be negatively correlated with patient age [4]. An elongation of the aorta is considered an age-associated change [5]. Particularly, aortic elongation could cause an inferior displacement of the His bundle and fast pathways. These findings strongly indicate that the slow pathway could be located close to the fast pathway in elderly patients. We recommend an anatomical assessment by CT in more elderly patients with a rotated or compressed heart indicated by the chest Xp or echocardiography. Although a 3D mapping system was not always necessary for the slow pathway ablation, the 3D mapping system allowed us to recognize the following landmarks: the maximal His potential recording site, CSOS, and most ventricular site along the tricuspid annulus and the precise location of the fast pathway, which could result in avoiding any unexpected atrioventricular block.
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Introduction As the indications for transvenous lead extraction expand and the number of extractions increases, surgeons face greater odds to encounter difficult cases. Several factors can complicate transvenous lead extraction, making it more challenging and dangerous. One of those factors is a longer implantation time [1].