Yumei Xue

Regulation of SCN3B/scn3b by Interleukin 2 (IL-2): IL-2 modulates SCN3B/scn3b transcript expression and increases sodium current in myocardial cells

BackgroundIn the initiation and maintenance of arrhythmia, inflammatory processes play an important role. IL-2 is a pro-inflammatory factor which is associated with the morbidity of arrhythmias, however, how IL-2 affects the cardiac electrophysiology is still unknown.MethodsIn the present study, we observed the effect of IL-2 by qRT-PCR on the transcription of ion channel genes including SCN2A, SCN3A, SCN4A, SCN5A, SCN9A, SCN10A, SCN1B, SCN2B, SCN3B, KCNN1, KCNJ5, KCNE1, KCNE2, KCNE3, KCND3, KCNQ1, KCNA5, KCNH2 and CACNA1C. Western blot assays and electrophysiological studies were performed to demonstrate the effect of IL-2 on the translation of SCN3B/scn3b and sodium currents.ResultsThe results showed that transcriptional level of SCN3B was up-regulated significantly in Hela cells (3.28-fold, pu2009=u20090.022 compared with the control group). Consistent results were verified in HL-1 cells (3.73-fold, pu2009=u20090.012 compared with the control group). The result of electrophysiological studies showed that sodium current density increased significantly in cells which treated by IL-2 and the effect of IL-2 on sodium currents was independent of SCN3B (1.4 folds, pu2009=u20090.023). Western blot analysis showed IL-2 lead to the significantly increasing of p53 and scn3b (2.1 folds, pu2009=u20090.021 for p53; 3.1 folds, pu2009=u20090.023 for scn3b) in HL-1 cells. Consistent results were showed in HEK293 cells using qRT-PCR analysis (1.43 folds for P53, pu2009=u20090.022; 1.57 folds for SCN3B, pu2009=u20090.05).ConclusionsThe present study suggested that IL-2, may play role in the arrhythmia by regulating the expression of SCN3B and sodium current density.

Features of accessory pathways in adult Ebstein's anomaly

AIMSnThe aim of the study was to describe the complex electrophysiological features of accessory pathways (APs) in adult Ebsteins anomaly (EA).nnnMETHODS AND RESULTSnWe performed a retrospective study of 17 consecutive adult EA cases with APs who underwent electrophysiological study and radiofrequency catheter ablation (RFCA) from November 2011 to May 2013. There were a total of 24 atrioventricular reentrant tachycardias (AVRTs) due to 23 APs, including 20 (87.0%) non-decremental conducting, 2 (8.7%) decremental conducting, and 1 (4.3%) nodofascicular bundle. Six (6/17 = 35.3%) patients had two APs while others had only one. Twenty-one APs (91.3%) in 15 patients were manifested and 2 APs (8.7%) in 2 patients were concealed. Six APs (26.1%) were broad, while 17 APs (73.9%) were narrow in width. Two patients suffered from duodromic tachycardias mediated by two APs. Accessory pathways were mainly located on the posterior, posteroseptal, and posterolateral tricuspid annulus (TA). Right ventriculography confirmed that all APs were located on the anatomic TA. All the patients remained free from tachycardias during 11.9 ± 6.8 months of follow-up after RFCA. For the 15 patients with manifest APs, 10 patients electrocardiograms (ECGs) after RFCA demonstrated morphologies of right bundle branch block, while 5 patients ECGs were normal.nnnCONCLUSIONSnAccessory pathways in EA are predominantly right-sided, manifest and localize to the lower half of the anatomic TA. A number of APs in EA have broad widths. The incidence of multiple APs is high in these patients and RFCA is effective.

A new electrophysiologic observation in patients with idiopathic left ventricular tachycardia

BACKGROUNDnIn patients with idiopathic left ventricular tachycardia (ILVT), the arrhythmogenic substrate is poorly understood.nnnOBJECTIVEnThe purpose of this study was to elucidate the ILVT characteristics and outcome of radiofrequency catheter ablation in patients with ILVT.nnnMETHODSnTwenty-four patients with ILVT and 15 patients with left accessory pathways (control) underwent high-density mapping of the left His-Purkinje system during sinus rhythm (SR) using 3-dimensional electroanatomic mapping.nnnRESULTSnFragmented antegrade Purkinje potential (FAP) was represented at the left ventricular septum slightly inferoposterior to the left posterior fascicle (LPF) in 23 patients with ILVT. In control subjects, no FAPs could be recorded at the same region, FAPs were identified at the proximal portion of the LPF (4 patients) and at the distal LPF (1 patient). The finding of any FAPs in ILVT patients was significantly higher than that in control patients (23/24 vs 5/15, P < .01). Radiofrequency ablation at the area of FAP resulted in successful ablation in 23 patients with ILVT. No ILVT recurred during follow-up of 16.3 ± 7.2 months.nnnCONCLUSIONnIn patients with ILVT, FAP located at the left ventricular septum slightly inferoposterior to the LPF is a novel finding using 3-dimensional electroanatomic mapping. The FAP may represent an arrhythmogenic substrate in ILVT and may be used for guiding successful ablation.

Trans-subclavian approach for radiofrequency ablation of premature ventricular contractions originating from subtricuspid annulus: a case report

BackgroundCatheter ablation has been established as a curative treatment strategy for ventricular arrhythmias. The standard procedure of most ventricular arrhythmias originating from the right ventricle is performed via the femoral vein. However, a femoral vein access may not achieve a successful ablation in some patients.Case presentationWe reported a case of a 29-year old patient with symptomatic premature ventricular contractions was referred for catheter ablation. Radiofrequency energy application at the earliest endocardial ventricular activation site via the right femoral vein could not eliminate the premature ventricular contractions. Epicardial mapping could not obtain an earlier ventricular activation when compared to the endocardial mapping, and at the earliest epicardial site could not provide an identical pace mapping. Finally, we redeployed the ablation catheter via the right subclavian vein by a long sheath. During mapping of the subvalvular area of the right ventricle, a site with a good pace mapping and early ventricular activation was found, and premature ventricular contractions were eliminated successfully.ConclusionVentricular arrhythmias originating from the subtricuspid annulus may be successfully abolished via a trans-subclavian approach and a long sheath. Although access via the right subclavian vein for mapping and ablation is an effective alternative, it is not a routine approach.

Evaluation of Electrophysiological Mechanisms of Post-Surgical Atrial Tachycardias Using an Automated Ultra−High-Density Mapping System

OBJECTIVESnThis study aimed to evaluate the electrophysiological mechanisms of post-surgical atrial tachycardias (ATs) during mapping with an automated high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts).nnnBACKGROUNDnMapping and ablation of post-operative ATs following previous open-heart surgery is often challenging because the potential mechanisms remain incompletely understood.nnnMETHODSnFifty-one consecutive patients underwent mapping and ablation of post-surgical ATs.nnnRESULTSnA total of 64 ATs were identified, and the mechanism was macro re-entry in 58 of 63 (92.1%) ATs, focal in 4xa0ATs, localized micro re-entry in 1 AT, and undetermined in 1 AT. Of 11 patients who underwent surgical repair of congenital heart disease, 6 (54.5%) had peri-tricuspid re-entrant AT, 5 had either right atrial (RA) free-wall incisional ATs or figure-8 re-entrant ATs, with an isthmus between the tricuspid annulus and the RA free-wall incision or between the incisions, and none had left atrial (LA) or focal ATs. In 32 patients with valve replacement and 8 who underwent valvuloplasty, peri-tricuspid ATs were observed in 14 (43.4%) and 6 (75%) patients, RA free wall or septal incisions-related ATs were seen in 7 and 2 patients, and LA macro re-entrant ATs were observed in 12 patients and 1 patient, respectively. A macro pseudo re-entry pattern was identified in 8 of 51 patients (15.7%). All these activations could be easily excluded by manually moving the window of interest, except in 2 cases with a figure-8 re-entrant configuration.nnnCONCLUSIONSnRA macro re-entrant ATs predominate, irrespective of the types of initial surgical procedures, but LA ATs occur more frequently in patients with valve replacement. Pseudo re-entry atrial activation is common and easily recognized by adjusting the mapping window.

A U-shaped relationship of body mass index on atrial fibrillation recurrence post ablation: A report from the Guangzhou atrial fibrillation ablation registry

Background Obesity or overweight is related to worse outcomes in patients with atrial fibrillation (AF) following catheter ablation (CA). The role of being underweight in relation to recurrent arrhythmias post AF ablation is less certain. We conducted a retrospective study to investigate the association of body mass index (BMI) with arrhythmia outcomes in AF patients undergoing CA. Methods In a cohort of 1410 AF patients (mean age 57.2u202f±u202f11.6u202fyears; 68% male) undergoing single CA, the association between BMI and AF ablation outcome was analyzed using BMI as a continuous variable and by four BMI categories (<18.5u202fkg/m2, 18.5-24u202fkg/m2, 25-29u202fkg/m2, andu202f≥u202f30u202fkg/m2). Result We observed a positive association between a cut off value of BMI and risk of AF recurrence post AF ablation. BMI ≥26.36u202fkg/m2 was related to more AF recurrence (c-statistic 0.55, 95%CI 0.51–0.58; Pu202f<u202f0.01) with 50% increased risk of AF recurrence (HR 1.50, 95% CI 1.22–1.86; Pu202f<u202f0.01). Recurrence rates in the four BMI categories were 33.3%, 23.2%, 27.2 and 41.8%, respectively (Pu202f<u202f0.01). Kaplan-Meier analysis showed that BMI categories of <18.5u202fkg/m2 andu202f≥u202f30u202fkg/m2 were all associated with more AF recurrence (Pu202f=u202f0.01). Both underweight (HR 1.85, 95%CI 1.12–3.08; Pu202f=u202f0.02) and obesity (HR 1.78, 95%CI 1.17–2.72; Pu202f=u202f0.01) significantly increased the risk of AF recurrence in a Cox proportional hazard model. Conclusion BMI had good predictive value for AF ablation outcomes with a cut off value of ≥26.36u202fkg/m2. Apart from being obese/overweight, being underweight might also be a risk factor for AF recurrence post ablation.

Reply: Cautionary Pulmonary Insufficiency in Ablation of Ventricular Arrhythmias From Pulmonary Sinus Cusps.

We thank Dr. Ren and colleagues for their interest in our article “Idiopathic Ventricular Arrhythmias Originating From the Pulmonary Sinus Cusp: Prevalence, Electrocardiographic/Electrophysiological Characteristics, and Catheter Ablation” [(1)][1]. The main issues raised by Dr. Ren and