Analysis of risk factors of ventricular arrhythmia in patients with Brugada syndrome / 中华心血管病杂志

Objective@#To investigate the risk factors of ventricular arrhythmias in patients with Brugada syndrome.@*Methods@#Clinical data of 60 Brugada syndrome patients admitted in the department of cardiology of the First Affiliated Hospital of Nanjing Medical University from March 2003 to December 2016 were collected and retrospectively analyzed. The age at diagnosis was (43.2±13.1) years (0.6-83.0 years), 98.3% were males (n=59), and the patients were followed up to (92±41) months (12-169 months). The 12-lead surface electrocardiogram (ECG) recorded at the time of diagnosis and showing the highest type 1 ST elevation, either spontaneously or after provocative drug test, was used for the analysis. Patients were divided into ventricular arrhythmia (VA, n=12) group and non-ventricular arrhythmia (non-VA, n=48) group depending on the presence or absence of clinical VA event. The demographic data and ECG data of the 2 groups were compared, and the independent risk factors of VA events were analyzed by stepwise logistic regression.@*Results@#Incidence of family history of sudden death (7/12 vs. 22.9% (11/48)) and percentage of type 1 ST elevation in the peripheral ECG leads (6/12 vs. 16.67% (8/48)) were significantly higher in VA group than in non-VA group (both P<0.05). Max Tpeak-Tend (Max-Tpe) interval ((144±53)ms vs. (110±16)ms) and dispersion of Tpe ((74±50)ms vs. (43±17)ms) were significantly higher in VA group than in non-VA group (both P<0.05). The area under receiver operating characteristic (ROC) curves for the Max-Tpe interval was 0.693 and Max-Tpe interval ≥140 ms was determined as an optimized cutoff point with increased risk of VA event, which had a sensitivity of 50.0%, a specificity of 98.0%, a positive predictive value of 85.7%, and a negative predictive value of 88.7% for predicting VA event. The ROC curves for the dispersion of Tpe was 0.775 and dispersion of Tpe ≥45 ms was determined as an optimized cutoff point for predicting VA event, which had a sensitivity of 91.7%, a specificity of 64.6%, a positive predictive value of 39.3%, and a negative predictive value of 96.9% for predicting VA event. In multivariate analysis, Max-Tpe interval ≥140 ms (OR=27.53, 95%CI 1.07-706.77, P=0.045) and family history of sudden death (OR=24.63, 95%CI 2.05-295.38, P=0.011) were found to be the independent risk factors of arrhythmic events.@*Conclusions@#Max-Tpe interval ≥140 ms and family history of sudden death are risk factors of VA event in included patients with Brugada syndrome.

Effects of renal denervation on left atrial fibrosis in rats with isoproterenol induced chronic heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of renal denervation (RDN) on left atrial fibrosis in rats with chronic heart failure.</p><p><b>METHODS</b>Sixty healthy male Sprague Dawley rats were randomly assigned to control group (n=10, intraperitoneal injection with 5 mg/kg normal saline daily for 3 consecutive weeks), sham group (n=25) and RDN group (n=25). Rats in sham and RDN group were intraperitoneally injected with 5 mg/kg isoproterenol daily for 3 consecutive weeks. RDN and sham RDN procedure was implemented at week 5. The renal arteries and veins were not isolated and the nerves were left intact in sham group. The experiment ended at week 10. Cardiac function, diastolic interventricular septal thickness (IVSD) and left atrial dimension (LAD) were evaluated by echocardiography at baseline, week 5 and 10. The rats of all three groups were sacrificed at week 10 and the left atrial tissue was used for following analysis: fibrosis was detected by Masson staining, plasma BNP was measured by ELISA kit, the protein expression of AngII, TGF-β1, MMP2 and collagen I was determined by Western blot.</p><p><b>RESULTS</b>(1) Cardiac function: compared with control group, LVEF decreased (P<0.01), IVSD (P<0.01) and LAD (P<0.01) increased significantly in the sham and RDN group at week 5. Compared with sham group at week 10, LVEF and IVSD significantly improved (P<0.05) and LAD tended to be smaller (P>0.05) in RDN group. (2) The degree of left atrial tissue fibrosis: Masson staining (collagen volume fraction, CVF) showed significantly decreased fibrosis of left atrial tissue in RDN group compared with that in sham group (P<0.01). (3) Plasma BNP level: ELISA assay revealed that plasma BNP in sham group was significantly increased compared with that in control group (P<0.05) and was similar between RND group and control group at week 10. (4) Protein expression of AngII, TGF-β1, MMP2 and collagen I in rats left atrial: Western blot analysis demonstrated that the expression of AngII, TGF-β1, MMP2 and collagen I was significantly down-regulated in RDN group compared to sham group (all P<0.05) but still significantly higher than in control group (all P<0.05).</p><p><b>CONCLUSIONS</b>RDN can effectively attenuate the left atrial fibrosis in rats with isoproterenol induced chronic heart failure. The attenuation of left atrial fibrosis by RDN in these rats may be attributed to improved cardiac function and downregulated pro-fibrogenic factors (AngII, TGF-β1, MMP2 and collagen I).</p>

The mode and clinical implications of onset of spontaneous tosade de pointes in the congenital long QT syndrome / 中国介入心脏病学杂志

Objective To study the mode and clinical implications of onset of spontaneous tosade de pointes in the congenital long QT syndrome. Methods We reviewed electrocardiograms (ECGs) of 55 patients with congenital QT syndrome for syncope. Documentation of the onset of tosade de pointes was available for 16 patients. All these patients had "definitive long QT syndrome" by accepted clinical and ECG criteria. Results One hundren and forty-nine runs of tosade de pointes were documented in 16 patients,of whom,there were 130 runs of pause-dependent tosade de pointes. Conclusion Our results show that the pause-dependent tosade de pointes,which has been recognized as a hallmark of tosade de pointes in the acquired long QT syndrome,plays a major role in the genesis of tosade de pointes in the congenital long QT syndrome.

Linkage analysis of five Chinese families with arrhythmogenic right ventricular cardiomyopathy using microsatellite genetic markers / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the linkage relationship between specific genetic markers and arrhythmogenic right ventricular cardiomyopathy (ARVC) in Chinese pedigrees.</p><p><b>METHODS</b>The microsatellite genetic markers D2S152, D14S252, and D10S1664 were studied for their linkages to ARVC in five Chinese ARVC pedigrees and a normal population of 121 Chinese individuals. Genomic DNA of the pedigrees and normal population was amplified using PCR techniques. Denaturing polyacrylamide sequencing gel (4%) electrophoresis was used to detect microsatellite repeat polymorphisms. Gels were silver-stained. A classical linkage analysis program was used assuming models of autosomal dominance and recession.</p><p><b>RESULTS</b>The logarithm of the odds (LOD) scores of D2S152 with ARVC in LW, WD, DS, LC and TY pedigrees were 2.174, -0.589, -infinity, - (indicating that linkage is not supported in this mode), and -infinity respectively in autosomal dominant model (recombination fraction = 0.000 respectively)and were -infinity, -infinity, -infinity, -infinity, and 0.182 respectively in the autosomal recessive model. The LOD scores of D14S252 with ARVC in LW, WD, DS, LC and TY pedigrees were -, -, -infinity, -, and 0 respectively in autosomal dominant model, and were -infinity, -0.812, -infinity, -infinity, and 0.087 respectively in autosomal recessive model. The LOD scores of D2S152 with ARVC in LW, WD, DS, LC and TY pedigrees were -, -0.539, -, and 0.602 respectively in autosomal dominant model and were -, -infinity, -infinity, -infinity, and - infinity respectively in autosomal recessive model.</p><p><b>CONCLUSIONS</b>The LOD score for D2S152 in the LW pedigree was 2.174, indicating that the chance of linkage is about 150:1. This suggests that there is a possible ARVC-related gene near this marker. There were no clear linkage relationships between ARVC and D10S1664 and D14S252 in this family, and no linkages between ARVC and any of the three genetic markers in the other four families. These results also suggest that there is genetic heterogeneity in LW and in the other pedigrees.</p>

Endocardial mapping and ablation of tachycardia guided by noncontact balloon catheter mapping system / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Changes of sarcoplamic reticular Ca(2+)-ATPase and IP(3)-I receptor mRNA expression in patients with atrial fibrillation / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate changes in the expression of sarcoplamic reticular Ca(2+)-ATPase (SERCA) and IP(3)-I receptors (IP(3)R(1)) mRNA in patients with atrial fibrillation.</p><p><b>METHODS</b>Thirty-eight patients with mitral stenosis undergoing open heart surgery were studied. 100 mg of atrial tissue was obtained during surgery from the right appendage and the right atrium. The amount of messenger ribonucleic acid (mRNA) amount of SERCA and IP(3)R(1) was measured by reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase (GAPDH).</p><p><b>RESULTS</b>Levels of mRNA expression of SERCA in patients with AF, as compared with subjects in sinus rhythm, was lower and that of IP(3)R(1) was higher. The longer AF was sustained, the higher the levels of mRNA. There was no significant difference between right atrial free wall and right appendage.</p><p><b>CONCLUSIONS</b>The expression changes of SERCA and IP3R mRNA may correlate with the initiation or maintenance of AF.</p>

Effect of radiofrequency catheter ablation treatment of supraventricular tachyarrhythmias on spontaneous attack of atrial fibrillation / 中国介入心脏病学杂志

Objective To evaluate the effect of radiofrequency catheter ablation treament of supraventricular tachyarrhythmias on spontaneous attack of atrial fibrillation (AF) and to further discuss the electrophysiological mechanisms of AF. Methods Thirty-one patients (20 men, 11 women; mean age 54?12 years, age range 24-69 years) with supraventricular tachyarrhythmias coexisting with AF were included in the study. The mean history of the study group was 9?5 (range 1-19) years and the mean number of AF attack was 6?5 times (range 2-18). Of the 31 cases, 5 supraventricular tachyarrhythmias were electrophysiologically proven to be typical atrial flutter (AFL), 17 atrioventricular reentrant tachycardia (AVRT), 9 atrioventricular nodal reentrant tachycardia (AVNRT). Linear lesions to make bi-directional block were done in cavo-tricuspid isthmus in AFL patients, slow pathway modification in AVNRT and accessory pathway ablation in AVRT. Results After mean follow-up of 39?19 months (range 12-72), of the 31 patients, 23 had no occurrence of AF. In 3 of the 5 AFL patients, no AF occurred after ablation, but 2 still had AF occurrence, of whom one had frequent atrial premature contractions (APCs) and short runs of AF. In 26 patients with supraventricular tachycardia, 20 had no occurrence of AF after ablation. In the remaining 6, 2 had less frequent occurrence, and 4 remained the same, of whom one had hypertention with enlarged left atrium, and another had frequent APCs and short runs of atrial tachycardia. Conclusion AFL may share the same substrate with AF or may be the trigger factor of AF, and AVNRT and AVRT are only trigger factors of AF. So after successful ablation treatment of these tachycardias, no AF occurs. But in some cases, AF substrate still exists, and AF can be triggered by other trigger factors besides tachycardias mentioned above.