RADIOFREQUENCY CURRENT CATHETER ABLATION OF THE LEFT ATRIOVENTRICULAR ACCESSORY PATHWAYS WITH PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA

Seventy patients with left atrioventricular accessory pathways and paroxysmal supraventricular tachycardia(PSVT) underwent radiofrequency catheter ablation(RFCA). The success rate was 94. 3%. Among these patients,26 had manifest preexcitation syndrome, and 44 had concealed preexcitation. Eighteen patients with concealed preexcitation underwent coronary sinus (CS) pacing, and delta wave appeared in 15. The keys to successful RFCA were correct positioning of the radiofrequency(RF) catheter tip, A/V amplitude ratio, AV interval (in sinus rhythm) and VA interval(during SVT or ventricular pacing). After 1～14 months of follow-up. two patients had supraventricular tachycardia(SVT) recurrence.

RADIOFREQUENCY CATHETER ABLATION OF PERMANENT ATRIAL FIBRILLATION UNDER GUIDANCE OF CARTO-MERGE TECHNIQUE

Objective To investigate the feasibility and effectiveness of radiofrequency catheter ablation (RFCA) to treat permanent atrial fibrillation (AF) under the guidance of Carto-Merge technique. Methods Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54.00±10.44 years, and duration of AF was 23.66±14.93 months. Cardiac magnetic resonance angiography (MRA) was performed to obtain pre-procedural three-dimensional (3D) images on the anatomy of left atrium (LA) and pulmonary veins (PVs) before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced. Results The episodes of AF were terminated during RFCA in 2 patients, by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively, AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter (AFL) in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day, 1st and 5th week respectively in 3 patients, and did not terminate after 3 months even though amiodarone was given. The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%. Conclusions Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping, lower expenses, and enhance the success rate of RFCA of permanent AF.

Endocardial mapping and ablation of tachycardia guided by noncontact balloon catheter mapping system

Objective To describe a new noncontact balloon catheter mapping system and to assess the clinical utility of this system for guiding endocardial mapping and ablation of tachycardia.Methods Five patients with tachycardia underwent endocardial mapping and radiofrequency ablation using the noncontact balloon catheter mapping system. A 9 French, 64-electrode balloon catheter and a conventional 7 French electrode catheter for mapping and ablation were positioned in the same ventricular chamber. Ventricular three-dimensional geometry was established by the computerized mapping system. Using a boundary element inverse solution, 3360 virtual endocardial electrograms were computerized and used to derive isopotential maps. The earliest endocardial activation site, the exit site and the activation sequence of tachycardia or the critical isthmus of the reentry circuit were identified. Radiofrequency ablation with circular or linear lesion was performed at the target sites guided by the locator system.Results Six clinical types of tachycardia, 5 of which were ventricular tachycardia and one was concealed fasciculoventricular fiber mediated tachycardia, were induced by programmed stimulation. The mean cycle length of these tachycardias was 336.6±42.69 msec. The earliest activation site and the exit site of 5 mapped tachycardias were all identified using the system. One type of ventricular tachycardia was hemodynamically unstable and difficult to terminate, and could not be mapped. Among the 6 types of tachycardias, radiofrequency ablation was successful in 4. There was no complication during and after the procedure. During the mean follow-up of 6 months, no tachycardia recurred in the patients with a successful ablation.Conclusions The noncontact mapping system described in this study has advantage over conventional mapping techniques for refractory tachycardia. It is not only helpful for understanding the electrophysiologic mechanism of a complex case, but also suitable for mapping hemodynamically-intolerated and nonsustained ventricular tachycardia.

Metabolic benefits of rivaroxaban in non-valvular atrial fibrillation patients after radiofrequency catheter ablation

Background and objective： Rivaroxaban is a new oral anticoagulant for stroke prevention in patients with non-valvular atrial fibrillation （NVAF）, which has less drug-food interaction than warfarin. We conducted this pro- spective randomized study to evaluate the metabolic benefits as well as the safety and efficacy with rivaroxaban versus warfarin in patients with NVAF following radiofrequency catheter ablation （RFCA）. Methods： From April to July 2014, 60 patients with NVAF undergoing RFCA were prospectively enrolled in our study. Following RFCA, all patients were randomly assigned to receive rivaroxaban （Group R, n=30） or warfarin （Group W, n=30）. Metabolic indices including serum total protein, albumin, globulin, and high-density lipoprotein （HDL） as well as bleeding, stroke, and systemic thromboembolism events were evaluated and compared during follow-up after 15, 30, 60, and 90 d of RFCA procedure. Results： Serum total protein, albumin, globulin, and HDL levels were all significantly elevated at each follow-up stage in Group R when compared to the baseline （P〈0.05 respectively）. In Group W, the metabolic indices decreased at first and then had an increasing trend. There were no deaths or thromboembolic complications in each group. The prevalence of total bleeding complications was similar between Group R and Group W （11/30, 36.7% vs. 10/30, 33.3%, P=0.70）. Conclusions： Patients with NVAF receiving rivaroxaban after RFCA procedures appear to benefit from a metabolic perspective compared with warfarin, providing practical clinical reference for the choice of the anticoagulant. Rivaroxaban seems to be as safe and effective in preventing thromboembolic events as warfarin for these patients.