An electrographic AV optimization for the maximum integrative atrioventricular and ventricular resynchronization in CRT.

BACKGROUND: Atrioventricular (AV) delay could affect AV and ventricular synchrony in cardiac resynchronization therapy (CRT). Strategies to optimize AV delay according to optimal AV synchrony (AVopt-AV) or ventricular synchrony (AVopt-V) would potentially be discordant. This study aimed to explore a new AV delay optimization algorithm guided by electrograms to obtain the maximum integrative effects of AV and ventricular resynchronization (opt-AV). METHODS: Forty-nine patients with CRT were enrolled. AVopt-AV was measured through the Ritter method. AVopt-V was obtained by yielding the narrowest QRS. The opt-AV was considered to be AVopt-AV or AVopt-V when their difference was < 20 ms, and to be the AV delay with the maximal aortic velocity-time integral between AVopt-AV and AVopt-V when their difference was > 20 ms. RESULTS: The results showed that sensing/pacing AVopt-AV (SAVopt-AV/PAVopt-AV) were correlated with atrial activation time (Pend-As/Pend-Ap) (P < 0.05). Sensing/pacing AVopt-V (SAVopt-V/PAVopt-V) was correlated with the intrinsic AV conduction time (As-Vs/Ap-Vs) (P < 0.01). The percentages of patients with more than 20 ms differences between SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V were 62.9% and 57.1%, respectively. Among them, opt-AV was linearly correlated with SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V. The sensing opt-AV (opt-SAV) = 0.1 × SAVopt-AV + 0.4 × SAVopt-V + 70 ms (R2 = 0.665, P < 0.01) and the pacing opt-AV (opt-PAV) = 0.25 × PAVopt-AV + 0.5 × PAVopt-V + 30 ms (R2 = 0.560, P < 0.01). CONCLUSION: The SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V were correlated with the atrial activation time and the intrinsic AV conduction interval respectively. Almost half of the patients had a > 20 ms difference between SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V. The opt-AV could be estimated based on electrogram parameters.

Comparative Effectiveness and Safety of Non-Vitamin K Antagonist Oral Anticoagulants in Atrial Fibrillation Patients.

BACKGROUND AND PURPOSE: Several observational studies have compared the effect of the non-vitamin K antagonist oral anticoagulants to each other in patients with atrial fibrillation. However, confounding by indication is a major problem when comparing non-vitamin K antagonist oral anticoagulant treatments in some of these studies. This meta-analysis was conducted to compare the effectiveness and safety between non-vitamin K antagonist oral anticoagulant and non-vitamin K antagonist oral anticoagulant by only including the propensity score matching studies. METHODS: We systematically searched the PubMed and Ovid databases until May 2020 to identify relevant observational studies. Hazard ratios (HRs) and 95% CIs of the reported outcomes were collected and then pooled by a random-effects model complemented with an inverse variance heterogeneity or quality effects model. RESULTS: A total of 17 retrospective cohort studies were included in this meta-analysis. Compared with dabigatran use, the use of rivaroxaban was significantly associated with increased risks of stroke or systemic embolism (HR, 1.16 [95% CI, 1.05-1.29]) and major bleeding (HR, 1.32 [95% CI, 1.24-1.41]), whereas the use of apixaban was associated with a reduced risk of major bleeding (HR, 0.78 [95% CI, 0.67-0.90]) but not stroke or systemic embolism (HR, 0.84 [95% CI, 0.56-1.28]). Compared with rivaroxaban use, the use of apixaban was associated with a decreased risk of major bleeding (HR, 0.63 [95% CI, 0.54-0.73]) but not stroke or systemic embolism (HR, 0.83 [95% CI, 0.67-1.04]). Reanalyses with the inverse variance heterogeneity or quality effects model produced similar results as the random-effects model. CONCLUSIONS: Current observational comparisons with propensity score matching methods suggest that apixaban might be a better choice compared with dabigatran or rivaroxaban for stroke prevention in atrial fibrillation patients.

Effect of Rivaroxaban or Apixaban in Atrial Fibrillation Patients with Stage 4-5 Chronic Kidney Disease or on Dialysis.

BACKGROUND: Anticoagulant treatment in non-valvular atrial fibrillation (AF) patients with severe chronic kidney disease (CKD) or on dialysis remains a matter of debate. The object of this study was to quantify the benefit-risk profiles of rivaroxaban or apixaban versus warfarin in AF patients with stage 4-5 CKD or on dialysis. METHOD: A comprehensive search of the Cochrane Library, PubMed, Ovid, and Google Scholar databases was performed for eligible studies that comparing the effect and safety of rivaroxaban or apixaban versus warfarin in AF patients with stage 4-5 CKD or on dialysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were abstracted, and then pooled using a random-effects model. RESULTS: A total of seven studies, one post hoc analysis of RCT and six observational cohorts, were included in this meta-analysis. Compared with warfarin use, the use of rivaroxaban or apixaban was significantly associated with reduced risks of all-cause death (HR = 0.82, 95% CI 0.72-0.93) and gastrointestinal bleeding (HR = 0.87, 95% CI 0.80-0.95). There were no significant differences in the risks of stroke or systemic embolism (rivaroxaban, HR = 0.71, 95% CI 0.43-1.19; apixaban, HR = 0.86, 95%CI 0.68-1.09) and major bleeding (rivaroxaban, HR = 0.96, 95% CI 0.64-1.45; apixaban, HR = 0.56, 95%CI 0.28-1.12). CONCLUSIONS: Current evidence suggests that rivaroxaban or apixaban are safe and at least as effective as warfarin in patients with AF and stage 4-5 CKD or on dialysis.

Electrophysiological characteristics of epicardial to endocardial breakthrough in intractable cavotricuspid isthmus-dependent atrial flutter.

BACKGROUND: Epicardial to endocardial breakthrough (EEB) exists widely in atrial arrhythmia and is a cause for intractable cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). This study aimed to investigate the electrophysiological features of EEB in EEB-related CTI dependent AFL. METHODS: Six patients with EEB-related CTI-dependent AFL were identified among 142 consecutive patients who underwent CTI-dependent AFL catheter ablation with an ultra-high-density, high-resolution mapping system in three institutions. Activation maps and ablation procedure were analyzed. RESULTS: A total of seven EEBs were found in six patients. Four EEBs (including three at the right atrial septum and one in paraseptal isthmus) were recorded in three patients during tachycardia. The other three EEBs were identified at the inferolateral right atrium (RA) during pacing from the coronary sinus. The conduction characteristics through the EEB-mediated structures were evaluated in three patients. Two patients only showed unidirectional conduction. Activation maps indicated that CTI-dependent AFL with EEB at the atrial septum was actually bi-atrial macro-reentrant atrial tachycardia (BiAT). Intensive ablation at the central isthmus could block CTI bidirectionally in four cases. However, ablation targeted at the inferolateral RA EEB was required in two cases. Meanwhile, local potentials at the EEB location gradually split into two components with a change in activation sequence. CONCLUSIONS: EEB is an underlying cause for intractable CTI-dependent AFL. EEB-mediated structure might show unidirectional conduction. CTI-dependent AFL with EEB at the atrial septum may represent BiAT. Intensive ablation targeting the central isthmus or EEB at the inferolateral RA could block the CTI bidirectionally.

Automatic annotation of local activation time was improved in idiopathic right ventricular outflow tract ventricular arrhythmia by novel electrogram "Lumipoint" algorithm.

PURPOSE: Precise automatic annotation of local activation time (LAT) is crucial for rapid high-density activation mapping in arrhythmia. However, it is still challenging in voltage-transitional areas where local low-amplitude near-field potentials are often obscured by large far-field potentials. The aim of this study was to explore the viability and validity of automatic identification of the earliest activation (EA) in idiopathic right ventricular outflow tract ventricular arrhythmias (RVOT VAs) using a novel Lumipoint algorithm. METHODS AND RESULTS: Twenty-seven patients with RVOT VAs were mapped with Rhythmia mapping system. Lumipoint algorithms were applied to reannotate the initial activation regions retrospectively. The results showed that LATs were reannotated in 35.0 ± 11.4% points in the initial activation area from bipolar activation breakout time (BBO) to the its 40 ms earlier timepoint. The automatically determined bipolar earliest activation time after Lumipoint reannotation (BEAT-lu: - 111.26 ± 12.13 ms) was significantly earlier than that before (BEAT: - 108.67 ± 12.25 ms, P = 0.000). Compared with manually corrected earliest activation time (EAT), the difference between EAT and BEAT-lu (DEAT-BEAT-lu: 6 (2-7) ms) was significantly smaller than that between EAT and BEAT (DEAT-BEAT/DEAT-UEA: 7 (4-11) ms, P = 0.000). The incidence of EAT and BEAT-lu being the same site was significantly higher than that between EAT and BEAT (48.15% vs 18.52%, P = 0.021). CONCLUSIONS: RVOT VAs often originate from voltage-transitional zone, and automatic annotation of LAT usually located at later high-amplitude far-field potential. Lumipoint algorithms could improve the accuracy of LAT automatic annotation, and it was plausible to ablate RVOT VAs just according to the automatically annotated BEAS-lu.

Efficacy and safety of xuezhikang once per day versus two times per day in patients with mild to moderate hypercholesterolaemia (APEX study): a protocol for a multicentre, prospective randomised controlled, open-label, non-inferiority study.

INTRODUCTION: Reduction in low-density lipoprotein cholesterol (LDL-C) improves clinical outcomes in patients with coronary artery disease. However, rates of lipid-lowering medication adherence are far from ideal. Reducing dosage frequency from multiple dosing to once-daily dosing may improve patients' medication adherence. Xuezhikang (XZK), an extract of Chinese red yeast rice, contains a family of naturally occurring statins and is traditionally prescribed as 600 mg two times per day. A comParative Efficacy study of XZK (APEX study) is designed to test the hypothesis that XZK prescribed 1200 mg once per day (OD group) is non-inferior to 600 mg two times per day (TD group) in patients with hypercholesterolaemia. METHODS AND ANALYSIS: The APEX study is a multicentre, prospective randomised controlled, open-label, non-inferiority study. We plan to recruit 316 patients aged ≥18 years with a diagnosis of mild to moderate hypercholesterolaemia for primary prevention. Patients will be randomised (1:1) to OD group and TD group. The OD group take XZK 1200 mg once per day after dinner while TD group take a traditional dose of 600 mg, two times per day after meals. Participants will have an 8-week medication period and be followed up at weeks 0, 4 and 8. The primary end point is the mean percentage change from baseline to week 8 in serum LDL-C. Secondary end points are safety and lipid-lowering effect on other lipoproteins and compliance. Data analyses will be on the intention-to-treat principle using non-inferiority analysis. ETHICS AND DISSEMINATION: The research had been approved by the Clinical Research and Laboratory Animal Ethics Committee of the First Affiliated Hospital, Sun Yat-sen University ((2017)286). The results will be reported through peer-reviewed journals, seminars and conference presentations. TRIAL REGISTRATION NUMBER: ChiCTR-IIR-17013660.

Electrophysiological characteristics of the earliest activation site in idiopathic right ventricular outflow tract arrhythmias under mini-electrode mapping.

INTRODUCTION: Right ventricular outflow tract ventricular arrhythmias (RVOT VAs) often originate in the voltage-transitional zone. The target electrogram could be compromised by the architecture of the roving catheter. Mini-electrodes could improve the mapping resolution, especially in low-voltage areas. The aim was to assess the electrophysiological characteristics of the earliest activation site (EAS) of RVOT VAs during mapping using mini-electrodes. METHODS AND RESULTS: Twenty-seven patients with RVOT-type VAs were mapped using Orion mini-electrodes and the Rhythmia mapping system. Bipolar and unipolar electrograms were analyzed and compared with conventional ablation catheter recordings. Twenty-five patients (25 of 27) were successfully mapped and ablated at the RVOT. At the EAS, all 25 (100%) patients exhibited local sharp potentials (spiky potential) at the VAs, and 88% (22 of 25) individuals showed reverse late potentials in adjacent sinus beats on the bipolar mini-electrode recordings. Related unipolar electrograms manifested 20% "q-plateau-QS," 76% "gross QS," and 4% "late QS" patterns related to spiky potential voltages and advanced times. Compared with electrograms recorded by ablation catheter, bipolar mini-electrode recordings exhibited significantly shorter spiky potential durations (P = 0.001) and a significantly increased incidence of the reverse late potentials (P = 0.041). Unipolar mini-electrode recordings had a lower incidence ratio of "late QS" patterns (P = 0.039). CONCLUSION: Compared with ablation catheter mapping, mini-electrodes improved the mapping resolution of the EAS of RVOT VAs and exhibited shorter spiky potential durations and reduced incidence of "later QS" unipolar patterns.

Improved blood pressure control with nifedipine GITS/valsartan combination versus high-dose valsartan monotherapy in mild-to-moderate hypertensive patients from Asia: results from the ADVISE study, a randomized trial.

AIMS: ADVISE was a 12-week, multicenter, randomized, prospective, open-label, parallel-group study comparing combination therapy of nifedipine GITS 30 mg plus valsartan 80 mg (N + V) with high-dose valsartan (160 mg) monotherapy (V160) in Asian patients with hypertension. METHODS: Patients with hypertension inadequately controlled with valsartan 80 mg for at least 4 weeks were randomized. The coprimary endpoints were the mean changes in clinic systolic and diastolic blood pressures (SBP and DBP, respectively) at Week 12. Other endpoints included blood pressure (BP) control rate, response rate, and adverse events. RESULTS: The full analysis set (FAS) comprised 359 patients. Least squares (LS) mean changes in SBP were -18.3 mmHg (N + V; n = 177) and -16.5 mmHg (V160; n = 182) (difference: -1.9 mmHg; P = 0.0998). DBP LS mean changes were -9.8 mmHg (N + V) and -7.4 mmHg (V160) (difference: -2.4 mmHg; P = 0.0011). BP control rates were significantly higher in the N + V group (Week 4: 51.2% vs. 38.4%, P = 0.0138; Week 8: 68.3% vs. 50.3%, P = 0.0004; and Week 12: 71.2% vs. 55.5%, P = 0.0024). Similar findings were observed when patients were stratified according to smoking status, SBP baseline quartiles, and ESC/ESH guideline-defined added-risk category. The BP response rate was also higher in the N + V group compared with the V160 group. Rates of adverse drug reactions (all mild-to-moderate) were similar: 4.5% (N + V) and 4.4% (V160). CONCLUSIONS: Although one of the coprimary endpoints did not reach statistical significance, combination treatment with N + V provided a greater early and more consistent BP-lowering effect than monotherapy with V160, including superior reduction in DBP and BP control rates.

Metformin attenuates ventricular hypertrophy by activating the AMP-activated protein kinase-endothelial nitric oxide synthase pathway in rats.

1. Metformin is an activator of AMP-activated protein kinase (AMPK). Recent studies suggest that pharmacological activation of AMPK inhibits cardiac hypertrophy. In the present study, we examined whether long-term treatment with metformin could attenuate ventricular hypertrophy in a rat model. The potential involvement of nitric oxide (NO) in the effects of metformin was also investigated. 2. Ventricular hypertrophy was established in rats by transaortic constriction (TAC). Starting 1 week after the TAC procedure, rats were treated with metformin (300 mg/kg per day, p.o.), N(G)-nitro-L-arginine methyl ester (L-NAME; 50 mg/kg per day, p.o.) or both for 8 weeks prior to the assessment of haemodynamic function and cardiac hypertrophy. 3. Cultured cardiomyocytes were used to examine the effects of metformin on the AMPK-endothelial NO synthase (eNOS) pathway. Cells were exposed to angiotensin (Ang) II (10⁻6 mol/L) for 24 h under serum-free conditions in the presence or absence of metformin (10⁻³ mol/L), compound C (10⁻6 mol/L), L-NAME (10⁻6 mol/L) or their combination. The rate of incorporation of [³H]-leucine was determined, western blotting analyses of AMPK-eNOS, neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) were undertaken and the concentration of NO in culture media was determined. 4. Transaortic constriction resulted in significant haemodynamic dysfunction and ventricular hypertrophy. Myocardial fibrosis was also evident. Treatment with metformin improved haemodynamic function and significantly attenuated ventricular hypertrophy. Most of the effects of metformin were abolished by concomitant L-NAME treatment. L-NAME on its own had no effect on haemodynamic function and ventricular hypertrophy in TAC rats. 5. In cardiomyocytes, metformin inhibited AngII-induced protein synthesis, an effect that was suppressed by the AMPK inhibitor compound C or the eNOS inhibitor L-NAME. The improvement in cardiac structure and function following metformin treatment was associated with enhanced phosphorylation of AMPK and eNOS and increased NO production. 6. The findings of the present study indicate that long-term treatment with metformin could attenuate ventricular hypertrophy induced by pressure overload via activation of AMPK and a downstream signalling pathway involving eNOS-NO.