Zhang Shulong

ASSA13-02-11 Single-Centre Results of Gender and Age Differences of Paroxysmal Supraventricular Tachycardia

Objective To study the gender and age differences of paroxysmal supraventricular tachycardia. Methods 1578 patients with consciously palpitations due to paroxysmal supraventricular tachycardia (PSVT) tachycardia were involved in this study. PSVT was confirmed by electrophysiological study and radiofrequency ablation in our hospital (including atrioventricular nodal reentrant tachycardia or bypass mediated atrioventricular reentrant tachycardia). Clinical data such as gender, age, type of disease, other types of arrhythmias were analysed. Results Gender exerts significant influences on the epidemiology, age at onset of various paroxysmal supraventricular tachycardia. With overall incidence, atrioventricular reentrant tachycardia (AVRT) is more common compared with atrioventricular nodal reentrant tachycardia (AVNRT) (AVRT VS AVNRT: 58.7% vs 41.3%). Compared to women, men with paroxysmal supraventricular tachycardia have a higher incidence of atrioventricular accessory pathways, a lower prevalence of atrioventricular nodal reentrant tachycardia. The average age of onset with different types of PSVT varies; it is also affected by gender. The average onset age of AVNRT group, whether in men or women are significantly greater than AVRT group (p < 0.001). The average onset age of dominant pathway-mediated AVRT occurs youger than the occult accessory pathway-mediated group, this significant differences is unaffected by gender. In addition, female onset age of the left side dominant pathway-mediated AVRT is significantly less than men (p = 0.007). Besides, different gender and age of onset play roles in the diagnosis of PSVT type. The diagnosis of AVRT is easier to set up with male whose onset age < 40 years of age (73% –76%). The AVRT seems to be more susceptible to the effects of gender and age; the incidence of AVRT exist two peak periods with female- 12 to 16 years old and 32 to 44 years old. But for man, the former peak incidence is during 16 to 20 years old, later than women, and the number of cases significantly reduced after 56-year-old. However, the incidence of AVNRT does not exist these characteristics. Conclusions The proportion of different types of PSVT affected by gender. Different gender and age of onset play roles in the diagnosis of PSVT type. The influence of gender and age on AVNRT seems to be smaller than AVRT, especially the incidence of dominant accessory pathway-mediated AVRT may be not just determined by genetic factors. The peak age of onset differ from sex. Two peak period of female AVRT showed same as the fluctuation of female lifetime hormone levels. And it is different with male, which may imply that the incidence of AVRT is also affected by the impact of female hormone.

ASSA13-02-6 Impact of Left Atrial Epicardial Adiposity on Recurrence of Atrial Fibrillation After Catheter Ablation

Objective To investigate the impact of left atrial epicardial adiposity on recurrence of atrial fibrillation (AF) after catheter ablation. Methods From 2009 to 2010, consecutive patients with AF who underwent circumferential pulmonary vein ablation guided by 3-D mapping system were enrolled in the retrospective study. Left atrial (LA) epicardial fat pad thickness was measured in consecutive cardiac CT angiograms performed for AF. Patients were grouped by AF burden: paroxysmal (n = 100), or persistent (n = 49) AF. The short-axis view was reconstructed as a plane perpendicular to the long axis of these 2 views at the level of the mid LA. In this short-axis view, the periatrial epicardial fat thickness was measured (in cm) as the shortest distance between the mid left atrium (LA) wall and 3 anatomic landmarks: oesophagus (LA-ESO), main pulmonary artery (LA-PA), and descending thoracic aorta (LA-TA) In a short-axis view at the mid LA, periatrial epicardial fat thickness was measured at the oesophagus (LA-ESO), main pulmonary artery, and thoracic aorta. The recurrence was defined as atrial tachyarrhythmia lasting more than 30 seconds beyond one month washout period. Results In this study population, 100 had paroxysmal AF, and 49 had persistent AF, 49 patients were female. The association between AF burden by grade (paroxysmal 1, persistent 2). Differences in gender, age, LVEF, and comorbid factors were not statistically significant. Periatrial LA-ESO fat thickness was assessed by ordinal logistic regression. Univariately, LA-ESO, LA-TA, LA-PA, and LAD were significant predictor of AF burden. After adjusting for age, BMI, LA-TA, LA-PA and LAD, the association remained significant (odds ratio, 0.407; 95% CI, 0.246 to 0.673; P = 0.00046). There was no loss to follow-up after 12 months. Of 149 patients, 98(65.8%) remained free of recurrence after a single ablation procedure. The recurrence patients had a significantly thicker LA-ESO fat pad than the normal patients after ablation. By logistic regression modelling, after adjusting for AF burden, LAD, age, and comorbid factors, LA-ESO fat depots were individually predictive of the recurrence of AF (P = 0.002, OR = 0.444.95%CI: 0.268–0.734). Conclusions Left atrial epicardial adiposity is associated with the burden of AF, and poorer outcomes after AF ablation. LA-ESO fat depots were individually predictive of the recurrence of AF.

ASSA13-12-1 The Change of the Tpeak-Tend Interval in Exercise Test Induced Myocardium Ischemia

Objective This study aims to evaluate whether myocardium ischemia induced by treadmill exercise testing (TET) will impact on Tpeak-Tend interval (Tpe). Methods Record the electrocardiogram of positive and control group before and at the peak of TET, measure and calculate the maximal Tpe, mean Tpe, QT dispersion (QTd) and Tpe of the leads with limited ST-segment deviation. Results 1. The comparison of the corrected maximal Tpe, mean Tpe and the corrected QTd is much longer at the peak of exercise test in positive group (P < 0.05). Before and at the peak of TET the difference of all above indexes in positive group are significant. 2.Tpe was longer in positive group compared to control group. The comparison of the leads corresponding to local myocardial ischemia in positive group showed Tpe in the peak of TET is longer than Tpe before TET. Conclusions Maximal, mean Tpe, QTd at the peak of test in positive group and Tpe of the leads with limited ST-segment deviation are significantly longer, prompting that the prolong of Tpe in exercise induced myocardial ischemia may reflect the increasing of ventricular dispersion of repolarization, and may indirectly reflect the myocardia ischemia.

ASSA13-02-3 The Impact of Volume of Pulmonary Veins Antrum and Left Atrium on Recurrence of Atrial Fibrillation After Radiofrequency Catheter Ablation in A Mid and Short-Term Period

Background and Objective The purpose of this research is to reconstruct 3-dimensional (3D) structure of the pulmonary veins and the left atrium through multislice computed tomography (MSCT), and then compare the variation of ostia, the antrum volume of pulmonary veins and the left atrium volume in AF patients with and without recurrence. Methods We consecutively enrolled sixty-five AF patients who accept RFCA therapy from June 2008 to January 2009, patients were followed up for one year from the day of RFCA. All patients were injected with intravenous constrast medium before being evaluated by 16-slice computed tomography (MSCT). The 3D reconstruction of PVs and left atrium was transformed into AW4.2 system, and we calculated the variation of pulmonary veins by Cardiac IQ software. Diameters of PVs ostia were measured by virtual endoscopy. The antrum volume of PVs and the left atrium volume were calculated by software volume rendering (VR). Results Pulmonary vein anatomical variations type in two groups showed no significant differences. The antrum volume of the bilateral PVs in the patients with recurrence was significantly larger than that in the patients without recurrence, left (3.84 ± 0.75 vs. 3.24 ± 0.49cm3, P < 0.05), right (4.95 ± 1.48 vs. 4.54 ± 1.11cm3, P < 0.01). The left atrium volume in the patients with recurrence group was also significantly larger than in the patients without recurrence group (99.85 ± 22.67 vs. 91.23 ± 17.31, P < 0.05), The antrum volume of bilateral PVs justified with left atrial volume had no significant difference between the two groups. Conclusions The maximum and minimum diameter of PVs ostia, the left atrium volume of bilateral PVs and left atrium in patients with recurrence group were significantly larger than no recurrence group. But it had no relationship with the atrium volume of bilateral PVs justified by left atrium volume.

ASSA13-02-17 Predictive Value of HATCH Score on Atrial Fibrillation Recurrence Post Radiofrequency Catheter Ablation

Background and Objective HATCH score is an established predictor of progression from paroxysmal to persistent atrial fibrillation (AF). The purpose of this study was to determine if HATCH score could predict recurrence of AF after radiofrequency catheter ablation (RFCA). Methods The data of 123 consecutive artial fibrillation patients who underwent an index circumferential pulmonary veins (PV) ablation were retrospectively analysed. Of theses patients, 65 (52.9%) patients had HATCH = 0, 41 (33.3%) patients had HATCH = 1, and 17 (13.8%) patients had HATCH≥2 (11 patients had HATCH = 2, 5 patients had HATCH = 3, 1 patients had HATCH = 4). The recurrence was defined as atrial tachyarrhythmia lasting more than 30 seconds after three months of RFCA. Results After 12 months follow-up, HATCH score was significant higher in recurrence group than in non-recurrence group (0.91 ± 0.94 vs 0.53 ± 0.80, P = 0.02). The recurrence rate were 27.7%, 36.6% and 64.7% in HATCH = 0, HATCH = 1, HATCH≥2 categories respectively. The ratio of patients with HATCH≥2 in recurrence group was higher than in no recurrence group (P = 0.007, OR = 4.06). The sensitivity and specificity of HATCH≥2 to discover recurrence was 25.0%, 92.4% respectively. Cumulative no recurrence rate of HATCH≥2 was lower than other scores analysised by Kaplan-Meier curve (P = 0.038). Conclusions HATCH score has a certain value in predicting AF recurrence after RFCA. HATCH≥2 has a high specificity to identify recurrence of AF after RFCA.

ASSA13-02-23 Relationship of Thickness of Left Atrial Epicardial Adipose Tissue and Atrial Fibrillation

Background Obesity is an important risk factor for atrial fibrillation (AF). Epicardial adipose tissue in close anatomic proximity to cardiac structures and autonomic fibres, is a source of several inflammatory mediators related to the genesis of AF. Objective This study is aimed to investigate the relationship of thickness of left atrial epicardial adipose tissue and atrial fibrillation. Methods 150 consecutive hospitalised patients with AF from January 2008 to January 2009 underwent 16-slice spiral CT as the experimental group, 48 (32%) patients with persistent AF, 102 (68%) patients with paroxysmal AF). 131 cases of non-AF patients in our outpatient for 16-slice spiral spiral CT were set up as a control group. In a short-axis view of the mid-left atrium (LA), periatrial epicardial adipose tissue was measured at the oesophagus (LA-ESO), main pulmonary artery (LA-PA), and thoracic aorta (LA-TA). Axial plane measurement of the anteroposterior diameter and sagittal measurement of the vertical diameter were performed as the LA diameter. Results Left atrial epicardial adipose tissue thickness in patients with persistent atrial fibrillation was significantly increased compared to that in patients with paroxysmal atrial fibrillation and without atrial fibrillation (all P value less than 0.05). Epicardial adipose tissue thickness in patients with persistent atrial fibrillation was significantly increased compared to patients with paroxysmal atrial fibrillation (all P value less than 0.05). Adjusted for age, sex, hypertension, diabetes, BMI and left atrial size, left trial epicardial adipose tissue thickness had relationship with AF history duration and AF burden. Conclusions Left atrial epicardial adipose tissue thickness was independently associated with AF duration and AF burden.

ASSA13-03-1 The Association of SNP Rs3825214 and Atrial Fibrillation in Chinese Han Population

Background Atrial fibrillation (AF) is the most common supraventricular tachycardia encountered in clinical practise associated with pronounced morbidity, mortality, and socio-economic burden. To date, mechanism of AF is still not fully understood but believed to be multifactorial including genetic predisposition. A number of genetic loci and genes related to the disorder have been reported. Recently, several genome-wide association studies (GWAS) have yielded associations between common sequence variants and ECG variables. SNP rs3825214, which is located in the last intron of the TBX5 gene, was shown correlating with the PR interval, the QRS duration, the QT interval and verified significant in diseases as atrial fibrillation, advanced AV block. The postulate that variants on TBX5 influence the occurrence of AF by a new mechanism different from the most extensively accepted ion channel theory may be potential possibility. Objective The aim of this study is to futher assess association between SNP rs3825214 and ECG parametres, AF, ventricular tachycardia (VT), as well as some arrhythmias associating with sudden cardiac death (SCD) in mainland chinese han population. Methods 692 patients as AF group, 235 patients as VT group, and 856 controls in GeneID population were enrolled for case-control association study. Peripheral blood of subjects was extracted through vein. Then cracking red blood cells, separating white blood cells, extracting genomic DNA by SDS alkali cracking method was performed. Genotyping using High Resolution Melt system was performed. The associations of both allele and genotype were analysised by accurate statistical analysis adjusting for potential confounding factors using SPSS 17.0 and PLINK v1.05. Results Subjects form Chinese GeneID population including 692 patients as atrial fibrillation (AF) group, 235 patients as ventricular tachycardia (VT) group, and 856 controls were enrolled in the study. No significant differences were found between the two groups and control subjects with regard to gender, age. we did not find PR interval, QRS duration, QT interval significantly associated with rs3825214. Of note, we observed the association between SNP rs3825214 and QTc (P = 0.047). There was no deviation from the Hardy-Weinberg equilibrium for SNP rs3825214 in control groups (P = 0.8361). Neither male group nor female group was associated with allelic G of SNP rs3825214. A significant association between G allele of SNP rs3825214 and lone atrial fibrillation (LAF) was arresting (P = 0.002; P-adj = 0.001, OR = 0.652). Analysis on other AF, which account for a large percentage in the AF group (60.3%), was shown no significant (P = 0.546). There was also no significant in VT group considering the total VT and other cardiovascular diseases such as bundle branch block, bradycardia, ER, hypertrophic cardiomyopathy, malignant ventricular arrhythmia. However, the assocition of G allele and AF in VT group showed a significant difference (P = 0.004). In both AF and LAF group, the distributions were significantly different compared to the control group with P value equals to 0.029 and 0.003 respectively. No significant interaction was observed between genotypes and ECG measures. Assuming a dominant genetic model, the GG shows strong significant association with AF, and especially LAF. The GG genotype could be a profond protective factor under dominant genetic model as the OR was 0.73 after adjusting for sex, age, T2DM, hypertension, stroke, and CAD. Conclusions The study detected the association of allele G of SNP rs3825214 in TBX5 with QTc and lone AF for the first time. The findings expand the GWAS results to other ethnic population and provide new insight into the molecular aetiology involved in the pathogenesis of lone AF.

ASSA13-02-5 Impact of Cervical Vagosympathetic Trunks Stimulation on Interleukin-1 and Interleukin-6 in Dogs with Rapid Atrial Pacing

Background Atrial fibrillation (AF) lead to calcium overload and Myocardial cell death, which could have inflammatory response in body. The autonomic nervous system (ANS) plays an important role in AF and inflammation. Objective The aim of the study was to explore effect of vagosympathetic trunks stimulationon IL-1 and IL-6 in dogs with rapid atrial pacing (RAP). Methods Fifteen mongrel dogs were randomly divided into three groups: cervical vagosympathetic nerve stimulation (VNS) group, RAP group, VNS+RAP group. Bbilateral cervical vagosympathetic trunks was isolated in every dog, and the cranial ends of the vagosympathetic nerves were ligated. A pair of Teflon-coated silver wires was inserted into the cervical vagosympathetic trunks for stimulation. A bipolar pacing catheter was placed in the high right atrium by way of the left jugular vein. In VNS group, vagus stimulator connected with silver wires to give electric stimulation in order to decrease the baseline heart rate by 50%. In RAP group, a acute atrial electrical remodelling (AAER) was performed through rapid atrial pacing at 600 beats/min with square waves of 2× threshold and 2 ms duration. In VNS+RAP group, dogs underwent both VNS and RAP. Blood samples were collected at 0h, 1h, 2h, 3h, 4h after RAP or VNS. Radioimmunoassay was preformed to measure the serum IL-1, IL-6 levels. Results In VNS group, Baseline IL-1 level was 97.05 ± 9.50pg/ml, the IL-1 level at 1h, 2h, 3h and 4h during stimulation were 102.05 ± 13.70 pg/ml, 106.39 ± 13.67 pg/ml, 99.61 ± 17.43 pg/ml, 106.30 ± 6.51 pg/ml. Baseline IL-6 level was 220.78 ± 6.22 pg/ml, the IL-1 level at 1h, 2h, 3h and 4h during stimulation were 216.46 ± 8.38 pg/ml, 207.26 ± 27.96 pg/ml, 213.71 ± 24.35 pg/ml, 229.05 ± 9.91 pg/ml. With VNS, there were no significant differences in the serum levels of IL-1, IL-6 throughout the 4-hour stimulation period. At RAP group, Baseline IL-1 level was 97.58 ± 3.2 pg/ml, the IL-1 level at 1h, 2h, 3h and 4h during stimulation were 100.23 ± 2.95 pg/ml, 103.18 ± 1.48 pg/ml, 109.97 ± 2.24 pg/ml, 118.81 ± 3.98 pg/ml. Baseline IL-6 level was 223.07 ± 1.72, the IL-6 level at 1h, 2h, 3h and 4h during stimulation were 225.78 ± 3.26 pg/ml, 230.60 ± 2.28 pg/ml, 235.41 ± 2.28 pg/ml, 245.65 ± 4.07 pg/ml. The IL-1, IL-6 levels elevated markedly after 2h of RAP, and were progressively elevated throughout the 4-hour pacing period. In VNS+RAP group, Baseline IL-1 level was 103.18 ± 1.48 pg/ml, the IL-1 level at 1h, 2h, 3h and 4h during stimulation were 111.44 ± 1.98 pg/ml, 141.82 ± 4.09 pg/ml, 176.62 ± 3.36 pg/ml, 214.07 ± 6.87 pg/ml. Baseline IL-6 level was 226.98 ± 2.23 pg/ml, the IL-6 level at 1h, 2h, 3h and 4h during stimulation were 237.22 ± 1.96 pg/ml, 273.05 ± 3.12 pg/ml, 314.00 ± 6.60 pg/ml, 353.14 ± 6.60 pg/ml. The IL-1, IL-6 levels elevated markedly after 1h of RAP, and wereprogressively elevated throughout the 4-hour pacing period. Compare with RAP Group, IL-1 levels significantly elevated after 2h in VNS+RAP group, IL-2 levels significantly elevated after 1h in VNS+RAP group, and both of them were progressively elevated throughout the 4-hour pacing period. Conclusions RAP could result in information. This further proof that the atrial fibrillation can cause inflammation; VNS without RAP can’t cause inflammation, but VNS can aggravate the inflammation caused by RAP. These findings suggest that ANS not only aggravate atrial electrical remodelling, but also lead to be structural remodelling via inflammation.

THE SUBSTRATE OF COMPLEX FRACTIONATED ATRIAL ELECTROGRAMS: EVIDENCE BY PATHOLOGIC ANALYSIS

Objectives Ablation of complex fractionated atrial electrograms (CFAE) is an important adjunctive therapy in atrial fibrillation (AF). The present study was to elucidate the substrate underlying CFAE. Methods Nine adult mongrel dogs were involved in the present study. AF was induced through rapid atrial pacing with vago sympathetic nerve stimulation. CFAE was recorded during AF. Ablation was performed at CFAE sites. Based on the location of the ablation scar, the atrial specimens were divided into CFAE and non-CFAE sites. Serial sections of the atrium were stained respectively with haematoxylin_eosin (HE) and the general neural marker protein gene product 9.5 (PGP9.5). We compared the characteristics of the myocardium and the ganglionated plexus (GPs) distribution between the CFAE and non-CFAE sites. Results The myocardium of non-CFAE sites was well-organised with little intercellular substance. However, the myocardium in the CFAE site was disorganised with more interstitial tissue (61.7±24.3% vs 34.1±9.2%, p<0.01). GPs in the CFAE site were more abundant than in non-CFAE sites ((34.45±37.46) bundles/cm2 vs (6.73±8.22) bundles/cm2, p<0.01). Conclusions The heterogeneity of the myocardium and GPs distribution may account for the substrate of CFAE and serve as a potential target of ablation.

EFFECT OF VAGAL NERVE ON THE MONOPHASIC ACTION POTENTIAL OF VENTRICULAR OUTFLOW TRACT

Objectives Vagal nerve may be related with idiopathetic ventricular tachycardia (IVT). The present study was aimed to investigate the effect of vagal nerve on the monophasic action potential (MAP) of ventricular outflow tract. Methods Eight adult mongrel dogs were involved. Bilateral vagosympathetic tunks were decentralised for stimulation. Metoprolol was given to block sympathetic effects. MAP was recorded at the LVOT, RVOT, RVA with or without vagal stimulation (VS) respectively. Results 90% of MAP duration (MAPD90) under VS was significantly shorter than baseline (p>0.05). With or without VS, the MAPD90 of RVA were significantly shorter than RVOT and LVOT (p<0.05), while there was no difference of MAPD90 between RVOT and LVOT. With VS, the abbreviation of MAPD90 at LVOT and RVOT was greater significantly than RVA (MAPD90: 12.1±3.9 at RVOT, 14.8±5.5 at LVOT vs 8.3±4.1 at RVA, p<0.05), while there was no difference of MAPD between LVOT and RVOT (p>0.05). Conclusions VS could reduce MAPD significantly. With VS, the abbreviation of MAPD90 at LVOT and RVOT was greater significantly than RVA. It suggested that outflow tract may be sensible to vagal modulation, which might be related to the occurrence of IVT. Conclusions VS could reduce MAPD significantly. With VS, the abbreviation of MAPD90 at LVOT and RVOT was greater significantly than RVA. It suggested that outflow tract may be sensible to vagal modulation, which might be related to the occurrence of IVT.