Yaodong Li

Renal sympathetic denervation suppresses atrial fibrillation induced by acute atrial ischemia/infarction through inhibition of cardiac sympathetic activity

OBJECTIVE This study aims to explore the effects of renal sympathetic denervation (RSD) on atrial fibrillation (AF) inducibility and sympathetic activity induced by acute atrial ischemia/infarction. METHODS Acute ischemia/infarction was induced in 12 beagle dogs by ligating coronary arteries that supply the atria. Six dogs in the sham-RSD group did not undergo RSD, and six dogs without coronary artery ligation served as controls. AF induction rate, sympathetic discharge, catecholamine concentration and densities of tyrosine hydroxylase-positive nerves were measured. RESULTS Acute atrial ischemia/infarction resulted in a significant increase of AF induction rate, which was decreased by RSD compared to controls (P<0.05). The root-mean-square peak value, peak area and number of sympathetic discharges were significantly augmented by atrial ischemia relative to the baseline and control (P<0.05). The number of sympathetic discharges was significantly reduced in the RSD group, compared to the control and sham-RSD groups (P<0.05). Norepinephrine and epinephrine concentrations in the atria, ventricle and kidney were elevated by atrial ischemia/infarction, but were reduced by RSD (P<0.05). CONCLUSIONS Sympathetic hyperactivity was associated with pacing-induced AF after acute atrial ischemia/infarction. RSD has the potential to reduce the incidence of new-onset AF after acute atrial ischemia/infarction. The inhibition of cardiac sympathetic activity by RSD may be one of the major underlying mechanisms for the marked reduction of AF inducibility.

Impact of contact force technology on reducing the recurrence and major complications of atrial fibrillation ablation: A systematic review and meta-analysis

Contact force (CF) monitoring can be useful in accomplishing circumferential pulmonary vein (PV) isolation for atrial fibrillation (AF). This meta-analysis aimed to assess the efficacy and safety of a CF-sensing catheter in treating AF. Randomized controlled trials or non-randomized observational studies comparing AF ablation using CF-sensing or standard non-CF (NCF)-sensing catheters were identified from PubMed, EMBASE, Cochrane Library, Wanfang Data, and China National Knowledge Infrastructure (January 1, 1998–2016). A total of 19 studies were included. The primary efficacy endpoint was AF recurrence within 12 months, which significantly improved using CF-sensing catheters compared with using NCF-sensing catheters [31.1% vs. 40.5%; risk ratio (RR)=0.82; 95% confidence interval (CI), 0.73–0.93; p<0.05]. Further, the acute PV reconnection (10.1% vs. 24.2%; RR=0.45; 95% CI, 0.32–0.63; p<0.05) and incidence of major complications (1.8% vs. 3.1%; OR=0.59; 95% CI, 0.37–0.95; p<0.05) significantly improved using CF-sensing catheters compared with using NCF-sensing catheters. Procedure parameters such as procedure duration [mean difference (MD)=-28.35; 95% CI, -39.54 to -17.16; p<0.05], ablation time (MD=-3.8; 95% CI, -6.6 to -1.0; p<0.05), fluoroscopy duration (MD=-8.18; 95% CI, -14.11 to -2.24; p<0.05), and radiation dose (standard MD=-0.75; 95% CI, -1.32 to -0.18; p<0.05] significantly reduced using CF-sensing catheters. CF-sensing catheter ablation of AF can reduce the incidence of major complications and generate better outcomes compared with NCF-sensing catheters during the 12-month follow-up period.

Effects of Cardiac Resynchronization Therapy on Ventricular Electrical Remodeling in Patients With Heart Failure

Cardiac resynchronization therapy (CRT) reverses structural remodeling of the left ventricle. We investigated whether CRT reverses left-ventricular electrical remodeling.Eighty patients were enrolled and implanted with CRT-devices. Echocardiography and electrocardiography data were obtained from each patient prior to implantation and two years after implantation. At two years after implantation, the patients were classified into a responder group and a non-responder group based on echocardiography.Over the next 2 years, 75 patients completed follow-up, and 5 patients had died. Echocardiography results showed that 23 patients could be classified as non-responders and 52 as responders. Larger numbers of non-responders were diagnosed with either ischemic cardiomyopathy (ICM) or nonspecific intraventricular conduction delay (NICD). The intrinsic QRS duration was not changed in responders, patients with dilated cardiomyopathy, or in the patient categories of male and female. However, the intrinsic QRS duration was significantly prolonged in non-responders and patients with ischemic cardiomyopathy (P = 0.041). The mean left ventricular end-diastolic diameter in the responder group was significantly decreased by CRT (P < 0.05), while there was no significant change in intrinsic QRS duration.While CRT does not reduce the intrinsic QRS duration, it can delay negative ventricular electrical remodeling. Continuous CRT is necessary.

The relationship between three X-linked genes and the risk for hypertension among northeastern Han Chinese

Background and objective: Incidences of hypertension are increasing and this condition is more common in men than in women. We selected six well-characterized polymorphisms from three X-linked genes (ACE2, AGTR2, apelin) aiming to investigate their interactive association with hypertension among northeastern Han Chinese. Methods and results: This was a case-control study involving 1009 hypertensive patients and 756 normotensive controls. All polymorphisms except rs3761581 in the apelin gene satisfied the Hardy-Weinberg equilibrium in females. The genotype and allele distributions of rs1403543 in the AGTR2 gene and rs56204867 in the apelin gene differed significantly between patients and controls for both genders, even after the Bonferroni correction (P<0.05/6). The risk prediction was significant for rs1403543 and rs56204867 under both additive and dominant models for both genders. In haplotype analysis, significance was seen for haplotype G-T-G-G-A (alleles in order of rs1978124, rs2106809, rs1403543, rs5194 and rs56204867), which was overrepresented in patients (5.15% versus 1.10% in controls, PSim=0.004). Interaction analysis indicated that all derived multifactor dimensionality reduction (MDR) models were non-significant for both genders. Conclusion: Our findings demonstrate that genetic defects in AGTR2 and apelin genes by themselves may play an independent leading role in determining susceptibility to hypertension in both genders.

Comparison of standard and modified transvenous techniques for complex pacemaker lead extractions in the context of cardiac implantable electronic device-related infections: a 10-year experience.

AIMS Complete lead extraction of cardiac implantable electronic devices (CIED) for device-related infections remains a complex procedure for chronically implantated leads. We present data from a single-centre registry of consecutive patients with extractions over 10 years. METHOD AND RESULTS Patients were identified from the centres electronic database with CIED-related infections who underwent lead extraction using either the standard technique and equipment or a modified innovative transvenous lead technique extraction using an ablation catheter. Of 151 patients with CIED-related infections, not responding to simple manual traction to effect lead extraction, average age 65 ± 8 years (range 45-82), 64% being male, 75 underwent standard (S) extraction, and 76 underwent modified (M) extraction. Procedural, lead extraction, and fluoroscopy exposure times with S and M methods, respectively, were 65 ± 14 vs. 52 ± 6 min (P < 0.01), 56 ± 12 vs. 36 ± 8 min (P < 0.001), and 48 ± 12 vs. 31 ± 7 min (P < 0.001). Retrieval rates were numerically lower with the standard technique at 92 vs. 96% but did not achieve significance, with respective complication rates of 6.7 and 5.3%. CONCLUSION In our single-centre study, a modified extraction technique to retrieve leads for infections of CIEDs using a steerable ablation catheter has improved procedural parameters over the standard technique, without compromising clinical lead extraction success rates. This may be a promising approach for a future, prospective trial.

Left atrial appendage occlusion in atrial fibrillation for stroke prevention: A systemic review

BACKGROUND Atrial fibrillation (AF) is an arrthymia characterized by increased risk of ventricle arrthymias and thromboembolism especially ischemic stroke. Most thrombus originated in the left atrial appendage, thus left atrial occlusion (LAAO) may be an effective alternative for stroke prevention in atrial fibrillation. OBJECTIVE To assess the effect and safety of left atrial occlusion for stroke prevention in atrial fibrillation. METHODS AND RESULTS We searched Pub Med, CENTRAL in The Cochrane Library, Embase, CBM-Disk, CNKI for published trials, ClinicalTrials.gov, ISI Proceedings for conference abstracts, and WHO International Clinical Trial registration Platform for ongoing studies. The search results were extracted, and then the quality of included studies was assessed. By RevMan 5.3, meta analysis was used if there was low heterogeneity. Three randomized controlled clinical trials involving 1165 participants were included (percutaneous 1114 in 2 trials, surgical 51 in 1 trial). The current data suggest that left atrial occlusion may be as efficacious as warfarin in stroke prevention (RR 0.78 [0.33, 1.84]) and mortality reduction (RR 0.68 [0.40, 1.16]) for AF. CONCLUSION In contrast to warfarin left atrial occlusion with Watchman device may have the same effectivity in stroke reduction. Surgical LAAO may also get positive outcomes compared with warfarin, but owing to the small sample size the evidence is less powerful. Total outcomes of percutaneous and surgical LAAO support this approach.

Effects of Ivabradine on Cardiac Electrophysiology in Dogs with Age-Related Atrial Fibrillation

Background Ivabradine is an inhibitor of mixed Na+-K+ current that could combine with HCN channels to reduce the transmembrane velocity of funny current (If), heart rate, and cardiac efficiency, and thus be used for the treatment of cardiovascular diseases such as chronic heart failure. As an ion channel blocker, Ivabradine is also a potential antiarrhythmic agent. Material/Methods Twelve aging dogs (8–10 years old) underwent rapid atrial pacing for 2 months to induce age-related AF in this study. The dogs were randomly divided into the Ivabradine group and aging-AF group. The effects of Ivabradine on the electrophysiological parameters, including the effective refractory period (ERP) of the pulmonary veins and atrium, duration of AF, and inducing rate of AF, were investigated. Results As compared to the aging-AF group, the ERPs of the left superior pulmonary vein (139.00±4.18 ms vs. 129.00±4.08 ms, P=0.005) and left auricle (135.00±3.53 ms vs. 122.00±4.47 ms, P=0.001) were significantly increased, while the duration of AF (46.60±5.07 s vs. 205.40±1.14 s, P=0.001) and inducing rate of AF (25% vs. 60%, P=0.001) were significantly decreased. Conclusions Ivabradine could effectively reduce the inducing rate of AF, and thus be used as an upstream drug for the prevention of age-related AF.

Reference values of brachial-ankle pulse wave velocity according to age and blood pressure in a central Asia population

Background Brachial-ankle pulse wave velocity (baPWV), a direct measure of aortic stiffness, has increasingly become an important assessment for cardiovascular risk. The present study established the reference and normal values of baPWV in a Central Asia population in Xinjiang, China. Methods We recruited participants from a central Asia population in Xinjiang, China. We performed multiple regression analysis to investigate the determinants of baPWV. The median and 10th-90th percentiles were calculated to establish the reference and normal values based on these categories. Results In total, 5,757 Han participants aged 15–88 years were included in the present study. Spearman correlation analysis showed that age (r = 0.587, p < 0.001) and mean blood pressure (MBP, r = 0.599, p <0.001) were the major factors influencing the values of baPWV in the reference population. Furthermore, in the multiple linear regression analysis, the standardized regression coefficients of age (0.445) and MBP (0.460) were much higher than those of body mass index, triglyceride, and glycemia (-0.054, 0.035, and 0.033, respectively). In the covariance analysis, after adjustment for age and MBP, only diabetes was the significant independent determinant of baPWV (p = 0.009). Thus, participants with diabetes were excluded from the reference value population. The reference values ranged from 14.3 to 25.2 m/s, and the normal values ranged from 13.9 to 21.2 m/s. Conclusions This is the first study that has established the reference and normal values for baPWV according to age and blood pressure in a Central Asia population.

TNNT2 Gene Polymorphisms are Associated with Susceptibility to Idiopathic Dilated Cardiomyopathy in Kazak and Han Chinese

Background Dilated cardiomyopathy (DCM) is characterized by left ventricular enlargement, systolic dysfunction, and heart failure. Both genetic and non-genetic factors have been linked to DCM pathogenesis. Familial DCM (FDCM) accounts for 20%–50% of all DCM cases, highlighting the importance of genetics in pathogenesis. Indeed, more than 40 DCM-associated genes have been identified, including the gene encoding cardiac troponin T type-2 (TNNT2). We examined polymorphisms of the TNNT2 gene in idiopathic DCM (IDCM) patients of Kazak and Han ethnicity compared with healthy Kazak and Han controls. Material/Methods Peripheral blood samples were collected from 180 patients with IDCM (90 Kazak and 90 Han), and 180 healthy controls (90 Kazak and 90 Han). PCR was used to amplify 15 exons and nearby introns of the TNNT2 gene. The amplified products were sequenced and compared to the standard sequence in PubMed by BLAST and CHROMAS software, to identify mutation sites. Results Results from Kazak and Han IDCM patients were complied for Hardy-Weinberg equilibrium analysis. There was a significant difference in the genotype distribution (χ2=6.67, P=0.015) and allele frequency (χ2=5.71, P=0.017) between Kazaks with IDCM and Kazak controls of SNP rs3729547. There was also a difference in the genotype distribution (χ2=6.62, P=0.036) and allele frequency (χ2=4.91, P=0.018) between Han with IDCM and Han controls. The TNNT2 gene polymorphism loci rs3729547 may be associated with the IDCM onset in Kazak and Han patients (OR=2.5, 95% CI: 1.233~5.068). Conclusions The TNNT2 polymorphisms might play an important role in susceptibility to DCM in Xinjiang Kazak and Han patients.

The safety and efficacy of second-generation cryoballoon ablation plus catheter ablation for persistent atrial fibrillation: A systematic review and meta-analysis.

Background Growing evidence suggests that second-generation cryoballoon ablation (2G-CB) is effective in patients with persistent atrial fibrillation (PerAF). The cornerstone of atrial fibrillation (AF) ablation is pulmonary vein isolation (PVI). The purpose of this study was to summarize the available data on the safety and mid-term (≥ 12 months) effectiveness of a ‘PVI-only’ strategy vs. a ‘PVI-plus’ strategy using 2G-CB in patients with PerAF. Methods We searched the PubMed, EMBASE and Cochrane library databases for studies on 2G-CB for PerAF. Group analysis was based on the ablation approach: ‘PVI-only’ versus ‘PVI-plus’, the latter of which involved PVI plus other substrate modifications. Studies showing clinical success rates at a follow-up (FU) of ≥ 12 months were included. Complication rates were also assessed. Data were analyzed by applying a fixed effects model. Results A total of 879 patients from 5 studies were analyzed. After a mid-term FU of 27 months, the overall success rate of 2G-CB for PerAF was 66.1%. In the ‘PVI-plus’ group, the success rate was 73.8%. In the ‘PVI-only’ group, the success rate was 53.6%. No heterogeneity was noted among studies (I2 = 0.0%, P = 0.82). Complications occurred in 5.2% of patients (P = 0.93), and the rate of phrenic nerve (PN) injury was 2.8% (P = 0.14). Vascular assess complications were the most frequent at 1.6% (P = 0.33). No death or myocardial infarction was reported. Conclusion ‘PVI-plus’ involving 2G-CB seems to be safe and effective for treating PerAF.