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Precise localization of the site of origin of premature ventricular contractions (PVCs) before ablation can facilitate the planning and execution of the electrophysiological procedure.The purpose of this study was to develop a predictive model that can be used to differentiate PVCs between the left ventricular outflow tract and right ventricular outflow tract (RVOT) using surface electrocardiogram characteristics.A total of 851 patients undergoing radiofrequency ablation of premature ventricular beats from January 2015 to March 2022 were enrolled. Ninety-two patients were excluded. The other 759 patients were enrolled into the development (n = 605), external validation (n = 104), or prospective cohort (n = 50). The development cohort consisted of the training group (n = 423) and the internal validation group (n = 182). Machine learning algorithms were used to construct predictive models for the origin of PVCs using body surface electrocardiogram features.In the development cohort, the Random Forest model showed a maximum receiver operating characteristic curve area of 0.96. In the external validation cohort, the Random Forest model surpasses 4 reported algorithms in predicting performance (accuracy 94.23%; sensitivity 97.10%; specificity 88.57%). In the prospective cohort, the Random Forest model showed good performance (accuracy 94.00%; sensitivity 85.71%; specificity 97.22%).Random Forest algorithm has improved the accuracy of distinguishing the origin of PVCs, which surpasses 4 previous standards, and would be used to identify the origin of PVCs before the interventional procedure.

Wolff-Parkinson-White (WPW) concomitant with atrial tachyarrhythmia (ATA) has not been systemically characterized.Detailed electroanatomical mapping of the right atrium (RA) and/or left atrium (LA) was performed using three-dimensional mapping and the accessory pathway (AP) was mapped.WPW syndrome with ATA was diagnosed in 11 patients (median age 60 years). The characteristic of unidirectional anterograde conduction over the AP was displayed in nine patients, six of whom were intermittent. Sustained atrial tachycardia, that is, counterclockwise atrial flutter (AFL) with a median tachycardia cycle length (TCL) of 225 (220-275) ms, was mapped in eight patients; furthermore, "figure 8" right atrial reentry was mapped with TCL 250 ms in one patient with a surgical history of ventricular septal defect repair. The remaining two patients underwent mitral annulus-dependent AT after paroxysmal atrial fibrillation (PAF) ablation and LA micro-reentry AT, respectively. In four patients, the location of the APs was left posterior. Left-lateral APs were identified in four patients. The locations of the APs in the remaining three patients were the right posterior and middle septum. All ATAs and APs were successfully ablated. After a median follow-up of 37 (15-72) months, no anterograde conduction over the AP was recorded, new onset of PAF was recorded in three patients, and all of them underwent circumferential pulmonary vein isolation.WPW with concomitant ATA frequently had continuous anterograde conduction over the AP with a rapid ventricular rate. Most WPWs displayed the characteristic of unidirectional anterograde conduction.

BackgroundNew-onset atrial fibrillation (NeAF) is common after cavotricuspid isthmus-dependent counterclockwise atrial flutter (CCW-AFL) ablation. This study aimed to investigate a simple predictive model of NeAF after CCW-AFL ablation.Methods and ResultsFrom January 2013 to December 2017, consecutive patients receiving CCW-AFL ablation were enrolled from three centers. Clinical, echocardiographic, and electrocardiographic data were collected and followed. Patients from two centers and another center were assigned into the derivation and validation cohorts, respectively. In the derivation cohort, logistic regression was performed to evaluate the ability of parameters to discriminate those with and without NeAF. A score system was developed and then validated. Two hundred seventy-one patients (mean 59.7±13.6 age; 205 male) were analyzed. During follow-up (73.0±6.5 months), 107 patients (39.5%) had NeAF. 190 and 81 patients were detected in the derivation and validation cohorts, respectively. Hypertension, age ≥70 years, left atrial diameter ≥42 mm, P wave duration ≥120 ms and the negative component of flutter wave in lead II ≥120 ms were selected as the final parameters. A weighted score was used to develop the HAD-AF score ranging from 0 to 9. In the derivation cohort, area under the receiver operating characteristic curve (AUC) was 0.938 (95% CI 0.902-0.974), superior to those of currently used CHA2DS2-VASC(0.679, 95% CI 0.600-0.757) and HATCH scores (0.651, 95% CI 0.571-0.730) (PConclusions39.5% of patients developed NeAF in 6 years after CCW-AFL ablation. HAD-AF score can reliably identify patients likely to develop NeAF after CCW-AFL ablation.Clinical PerspectiveWhat Is New?During a follow-up period of more than 6 years after CCW-AFL ablation, 107 of 271 (39.5%) patients developed NeAF.HAD-AF score, based on easily obtainable clinical, echocardiographic and electrocardiographic parameters, could better predict development of NeAF after CCW-AFL ablation (area under the receiver operating characteristics curve [AUC], 0.938), compared with currently used HATCH score (AUC, 0.651) and CHA2DS2-VASCscore (AUC, 0.679) (PWhat Are the Clinical Implications?In CCW-AFL patients with a HAD-AF score >4, close postoperative follow-up for earlier detection of AF should be recommended, or the option of concomitant AF ablation could be considered during the shared decision-making process.

Background Atrial tachycardias (ATs) frequently develop after a surgical Maze procedure. We aimed to elucidate the electrophysiologic mechanisms and their arrhythmogenic substrates of these ATs. Methods and results We retrospectively reviewed 20 patients (14 females, mean age of 55.5 ± 8.6 years) with post-Maze ATs who underwent high-resolution mapping at three institutions. The slow conduction areas, reentry circuits, voltage signals, complex electrograms, and their correlation with the surgical incisions and lesions placed in the surgical Maze procedures were analyzed. Thirty-six ATs with a mean cycle length of 260.0 ± 67.6 ms were mapped in these patients. Among them, 22 (61.1%) were anatomical macro-reentrant ATs (AMAT), 12 (33.3%) non-AMATs (localized ATs), and 2 (5.6%) focal ATs, respectively. Epicardial conduction bridges were observed in 6/20 (30.0%) patients and 7/36 (19.4%) ATs. Different arrhythmogenic substrates were identified in these ATs, including slow conduction regions within the previous lesion areas or between the incisions and anatomical structures, the prolonged activation pathways caused by the short lesions connecting the tricuspid annulus, and the circuits around the long incisions and/or lesions. Conclusions Reentry is the main mechanism of the post-Maze ATs. The pro-arrhythmic substrates are most likely caused by surgical incisions and lesions. The slow conduction regions and the protected channels yielded from these areas are the major arrhythmogenic factors.

Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas.In total, 9 patients (6 males, mean age 32 ± 13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site.VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A "QS" type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p0.001). Endocardial and epicardial mapping revealed pre-maturities of -11 ± 4 ms and -25 ± 8 ms, respectively (VS. -28 ± 8 ms revealed by endocardial mapping in control patients, p0.001 and p=0.389, respectively). All of the study cases demonstrated an "rS" pattern in the endocardial unipolar electrogram. Acute and long-term successful ablation (a median of 11 months of follow-up) was achieved in all patients without complications.A distinct group of idiopathic VAs remote from the summit and crux areas warranting ablation by a subxiphoid approach were identified. Morphological ECG features of a "QS" type among the location-related grouped leads combined with the mapping findings helped in the identification of the epicardial site of origin.

This letter presents a novel method for instantaneous air temperature under cloudy conditions (Ta,cloudy) estimation using satellite-derived cloud top temperature (CTT), cloud top height (CTH), and Global Forecast System (GFS) forecasts. The radiosonde profiles were used to analyze the relationship between Ta,cloudy and CTT, CTH. The results showed that it is feasible to estimate Ta,cloudy using CTT and CTH, especially for low and middle cloud conditions. Linear and neural network (NN)-based Ta,cloudy estimation models were constructed and validated using the Visible Infrared Imaging Radiometer Suite (VIIRS) CTT, CTH, and GFS Tair for summer 2017 and 2018. The NN model performs better than the linear model, and GFS Tair can obviously improve the accuracy of Ta,cloudy estimation. The correlation coefficient (R), root-mean-square error (RMSE), and bias of the NN model with GFS Tair were 0.953, 1.950 °C, and -0.030 °C, respectively. The estimation model performed better under low and warm clouds than high and cold cloud conditions.

Introduction: For those cardiac resynchronization therapy (CRT) candidates who experience left-ventricular (LV) lead placement failure or underwent concomitant cardiac surgeries, surgical placement of epicardial LV lead guided by electroanatomic mapping may be a promising alternative. Methods: Electroanatomic mapping was used to guide positioning of the LV lead through a surgical approach. The LV lead was placed at the region with the latest local LV activation and normal voltage, away from the scar. Results: From April 2010 to September 2018, 10 consecutive patients (3 female) underwent surgical epicardial LV lead implantation. Among them, 3 had other surgical indications simultaneously (including 1 CRT non-responder), and 7 had failed transvenous LV lead placement. After CRT, the QRS duration was shortened from 149.3 ± 20.4 ms to 125.1 ± 15.2 ms (p = 0.01). At 6 months, the LV ejection fraction was significantly improved and remained stable in the follow-up (FU) period thereafter (baseline vs. 6 months, 31.0 ± 8.3% vs. 42.2 ± 13.4%, p = 0.006). Other parameters, including the threshold and impedance of the LV lead, were also stable at a mean FU of 755 ± 406 days, and the NYHA functional classification decreased from 2.9 ± 0.7 to 1.8 ± 0.8 (p = 0.002). Conclusions: Placement of an epicardial LV lead guided by electroanatomic mapping could be used as an adjunctive strategy in patients who were unable or refractory to conventional CRT therapy. This approach could also be applied in patients who had other surgical indications at the same time.

The characteristics and genesis of the calcite veins in Carboniferous basalt in the east slope of Mahu Sag, Junggar Basin are investigated based on observation of cores and thin sections; analyses of X-ray fluorescence, in situ major, trace and rare earth elements (REE), carbon, oxygen and strontium isotopes, fluid inclusions, as well as basin modeling. There are three periods of calcite fillings. The Period I calcite is characterized by low Mn content, flat REE pattern, strong negative cerium (Ce) anomaly, weak to moderate negative Eu anomaly, and light carbon isotopic composition, indicating the formation of the calcite was affected by meteoric water. The Period II calcite shows higher Mn and light REE contents, weak positive Ce anomaly and slight positive europium (Eu) anomaly, and a little heavier carbon isotopic composition and slightly lower strontium isotope ratio than the Period I calcite, suggesting that deep diagenetic fluids affected the formation of the Period II calcite to some extent. The Period III calcite is rich in iron and manganese and has REE pattern similar to that of the Period II calcite, but the cerium and europium enomalies vary significantly. The Period I and II calcites were formed in shallow diagenetic environment at approximately 250–260 Ma, corresponding to Late Hercynian orogeny at Late Permian. The Period III calcite was probably formed in the Indo-China movement during Late Triassic. It is believed that the precipitation of calcite in basalt fractures near unconformity was related to leaching and dissolution of carbonates in the overlying Lower Permian Fengcheng Formation by meteoric water, which destructed the Carboniferous weathering crust reservoirs in early stage. Relatively high quality reservoirs could be developed in positions with weak filling and strong late dissolution, such as structural high parts with Fengcheng Formation missing, distant strata from Fengcheng Formation vertically, buried hills inside lake basin, etc.

BackgroundPulmonary vein isolation (PVI) is the standard ablation strategy for treating atrial fibrillation (AF). However, the optimal strategy of a repeat procedure for PVI non-responders remains unclear.ObjectiveThis study aims to investigate the incidence of PVI non-responders in patients undergoing a repeat procedure, as well as the predictors for the recurrence of repeat ablation.MethodsA total of 276 consecutive patients who underwent repeat ablation from August 2016 to July 2019 in two centers were screened. A total of 64 (22%) patients with durable PVI were enrolled. Techniques such as low voltage zone modification, linear ablation, non-PV trigger ablation, and empirical superior vena cava (SVC) isolation were conducted.ResultsAfter the 20.0 ± 9.9 month follow-up, 42 (65.6%) patients were free from atrial arrhythmias. A significant difference was reported between the recurrent and non-recurrent groups in non-paroxysmal AF (50 vs. 23.8%, p = 0.038), diabetes mellitus (27.3 vs. 4.8%, p = 0.02), and empirical superior vena cava (SVC) isolation (28.6 vs. 60.5%, p = 0.019). Multivariate regression analysis demonstrated that empirical SVC isolation was an independent predictor of freedom from recurrence (95% CI: 1.64–32.8, p = 0.009). Kaplan-Meier curve demonstrates significant difference in recurrence between empirical and non-empirical SVC isolation groups (HR: 0.338; 95% CI: 0.131–0.873; p = 0.025).ConclusionAbout 22% of patients in repeat procedures were PVI non-responders. Non-paroxysmal AF and diabetes mellitus were associated with recurrence post-re-ablation. Empirical SVC isolation could potentially improve the outcome of repeat procedures in PVI non-responders.

Febuxostat is a xanthine oxidase inhibitor used to reduce the formation of uric acid and prevent gout attacks. Previous studies have suggested that febuxostat was associated with a higher risk of cardiovascular events, including atrial fibrillation, compared with allopurinol, another anti-hyperuricemia drug. Whereas in our clinical practice, we identified 2 cases of febuxostat-associated ventricular tachycardia (VT) events. The proarrhythmogenic effects of febuxostat on human cardiomyocytes and underlined mechanisms remain poorly understood. In this study, we employed real-time cell analysis and calcium transient to investigate the effects of febuxostat on the cytotoxicity and electrophysiology properties of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Up to 10 μM febuxostat treatment did not show toxicity to cell viability. However, 48-h febuxostat exposure generated dose-dependent increased irregular calcium transients and decreased calcium transient amplitude. Furthermore, RNA-seq analysis indicated that the MAPK signaling pathway was enriched in the febuxostat-treated group, especially the protein kinases c-Jun N-terminal kinase (JNK). Western blotting of 3 main protein kinases demonstrated that JNK activation is related to febuxostat-induced arrhythmia rather than extracellular signal regulated kinases (ERK) or p38. The dysfunctional calcium dynamics of febuxostat-treated hiPSC-CMs could be ameliorated by SP600125, the inhibitor of JNK. In conclusion, our study demonstrated that febuxostat increases the predisposition to ventricular arrhythmia by dysregulating calcium dynamics.

Several satellites have been launched to monitor the increasing concentrations of greenhouse gases, especially CO2 and CH4 in the atmosphere, through backscattered hyperspectral radiance in the shortwave infrared (SWIR) band. The vertical profiles of greenhouse gases and aerosols could strongly affect the results from these instruments. To investigate the effects of the vertical distribution of CO2 on the uncertainty of SWIR satellite retrieval results, we conducted observations of the vertical profiles of CO2 , CH4 and aerosol particles at 0.6–7 km above sea level using a Beechcraft King Air 350ER in Jiansanjiang (46.77 ∘ N, 131.99 ∘ E), Heilongjiang Province, northeast China, on 7–12 August 2018. The profiles from this aircraft captured a decrease in CO2 from 2 km to the minimum altitude due to the absorption of vegetation at the surface in summer. CH4 measurements showed about a 0.2 ppm increase from 2.0 to 0.6 km on 10 August, which may result from emissions from the large area of paddy fields below, and a constant mole fraction between 1.951 and 1.976 ppm was recorded at 2 km and above. Comparison of CO2 profiles from a new version of the carbon cycle data assimilation system Tan-Tracker (v1), retrievals from OCO-2 and aircraft measurements was conducted. The results from OCO-2 and the assimilation model system Tan-Tracker captured the vertical structure of CO2 above 3 km, whereas below 3 km the values from OCO-2 and the Tan-Tracker model were lower than those from in situ measurements. Column-averaged CO2 volume mole fractions calculated from in situ measurements showed biases of - 4.68 ± 0.44 ppm ( - 1.18 ± 0.11 % ) compared to OCO-2 retrievals.

Precipitable water vapour (PWV) plays an important role in weather prediction, hydrological cycles and climate change. In this study, a physics-based algorithm was proposed to retrieve PWV over lan...

To assess the prevalence and management of atrial thrombus in patients with nonvalvular atrial fibrillation (NVAF) and identify the risk factors of the nonresolution of atrial thrombus. This single-center retrospective observational study consecutively enrolled patients with NVAF and atrial thrombus detected using transesophageal echocardiography (TEE) or cardiac computed tomography angiography (CTA) from January 2012 to December 2020. Patients with prior left atrial appendage (LAA) intervention were excluded. The primary endpoint was the presence of atrial thrombus, while the secondary endpoint was the complete resolution of atrial thrombus. The prevalence of atrial thrombus in patients with NVAF was 1.4%. Ninety patients with atrial thrombus (mean age 62.8 ± 11.9 years and 61.1% men) were finally analyzed. Atrial thrombus was in the LAA in 82 (91.1%) patients. During follow up, 60% of the patients showed complete resolution of atrial thrombus. Congestive heart failure (odds ratio [OR]: 8.94; 95% confidence interval [CI]: 1.67-47.80) and a history of ischemic stroke (OR: 8.28; 95% CI: 1.48-46.42) were independently associated with the risk of the nonresolution of atrial thrombus. The presence of atrial thrombus in patients with NVAF who received anticoagulation therapy is non-negligible. Even in anticoagulated patients, TEE or cardiac CTA might still be needed. Congestive heart failure and a history of ischemic stroke are risk factors of the nonresolution of atrial thrombus.

Re-ablation has an important role in the control of recurrent atrial fibrillation (AF) post the first ablation. The present study was to report the outcome of AF re-ablation for patients who recurred after initial ablation, and to characterize the clinical and electrophysiological features predicting recurrence after redo ablation. From January 2012 to May 2017, patients undergoing re-ablation for AF in our hospital were consecutively enrolled. Clinical and electrophysiological data for the initial and second procedure were collected retrospectively and prospectively, respectively. All patients were followed up for one year and recurrences during the time were reported. Totally 259 patients entered into the analysis (age, 58.4 ± 10.5 years; 169 men). At the end of one-year follow-up, 85 patients recurred with atrial arrhythmias (32.8%). In the multivariate analysis, higher CHA2DS2-VASC score (p = 0.023, 95% CI 1.03–1.53) and shorter time to recurrence after the initial ablation (p = 0.001, 95% CI 0.93–0.98) were clinical factors predictive of one-year recurrence after the repeat ablation. The reconnection of the right pulmonary vein (PV) (p = 0.034, 95% CI 0.31–0.96) and the absence of not eliminated non-PV trigger at the second procedure (p = 0.032, 95% CI 1.25–142.80) independently predicted the better re-ablation outcome. About one-third of patients recurred after one year following re-ablation. CHA2DS2-VASC score and time to recurrence after the initial ablation were independent clinical factors predicting recurrence. Also, electrophysiological findings during the repeat ablation (the right PV reconnection and absence of not eliminated non-PV trigger) were associated with better outcome during one year of follow-up.

PRKAG2 cardiomyopathy is a rare progressive disease characterized by increased ventricular wall thickness and preexcitation. Dysfunction of the protein 5'-AMP-activated protein kinase (AMPK) plays a decisive role in the progression of ventricular lesions. Although patients with the

Background The literature on laminopathy with ventricular phenotype is extensive. However, the pathogenicity of LMNA variations in atrial lesions still lacks research. Objective To characterize the atrial phenotype and possible mechanisms in a large Chinese family with heart-hand syndrome carrying LMNA missense variant in rod 2B domain (c.1003C>T p.R335W). Methods Clinical characteristics were collected based on the pedigree investigation. Comprehensive functional analyses, including molecular dynamic simulation, cellular, and animal functional assays, determined the pathogenicity in atrial myopathy. Results In the pedigree investigation, 6/13 of the mutation carriers showed heterogeneous cardiac phenotypes, and eight carriers also had brachydactyly. In silico molecular dynamics simulations predicted increased binding energy of R335W mutant lamin A. Atrial cardiomyocytes (HL-1, hiPSC-derived atrial cardiomyocytes) expressing R335W showed abnormal nuclear morphology, compromised DNA repair, and dysfunctional contraction. Adult zebrafish expressing mutant lamin A showed increased P wave duration in the electrocardiogram, decreased A peak velocity in echocardiography, and atrial lesions under the transmission electron microscope. Conclusion The LMNA p.R335W mutation leads to a familial heart-hand syndrome characterized by an overlapping phenotype of prominent atrial lesions and brachydactyly. The unstable lamin dimerization and impaired DNA repair are possible mechanisms underlying cardiac phenotypes. Our findings consolidated the genetic role in the course of atrial arrhythmias and cardiac aging, which is helpful to the diagnosis and treatment of cardiac laminopathy.

The Backward Limb Spectrometer (BLS) onboard the Tiangong-2 (TG-2) space laboratory, the first spaceborne limb sounding instrument of China, was successfully launched on 15 September 2016, and its measurements of scattered photons of sunlight along the limb line-of-sight (LOS) in the 290–1000 nm range could be used to derive the vertical distribution of stratospheric ozone with high vertical resolution. Ozone profiles with a vertical resolution of one km in 10–40 km and 30–50 km were retrieved by the triplet and pair methods, respectively, and the ozone profiles retrieved by the BLS were compared with the ozone sounding data over four sounding stations. Meanwhile, the Ozone Mapping and Profiler Suite Limb Profiler (OMPS/LP) version 2.5 (v2.5) stratospheric ozone profile product was also introduced for comparison. The retrieval results showed a good agreement with the ozone profiles of ozone sounding and the OMPS/LP v2.5 product, and the differences were basically within 25% above 20 km, while relatively larger differences occasionally occurred below 20 km. The case studies over four sites worldwide demonstrate that the BLS is capable of measuring stratospheric ozone profiles with high vertical resolution.

Aims Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas. Methods In total, 9 patients (6 males, mean age 32±13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site. Results VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A “QS” type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p

The Visible and Infrared Spin-Scan Radiometer (VISSR) onboard the Fengyun-2 (FY-2) satellite can provide valuable thermal infrared observations to help create a precipitable water vapor (PWV) product with high spatial and temporal resolutions. The current FY-2/VISSR PWV product in operation is produced by using a traditional two-band physical split-window (PSW) method, which produces low quality results under dry atmospheric conditions. Based on the sensitivity characteristics of FY-2F/VISSR water vapor channel and two split-window channels to atmospheric water vapor, this study developed a new, robust operational PWV retrieval algorithm for FY-2F to improve the operational precision of the current PWV product. The algorithm uses a modified three-band PSW method, which adds a scale for the water vapor channel in the improved three-band PSW method. Integrated PWV products from the radiosonde data in 2016 are used here to validate the precision of the PWV retrieved by the modified three-band and traditional two-band PSW methods. The mean bias, root mean square error (RMSE), and correlation coefficient of the PWV retrieved by the modified three-band PSW method are 0.28 mm, 4.53 mm, and 0.969, respectively. The accuracy is much better than the PWV retrieved by the two-band method, whose mean bias, RMSE, and correlation coefficient are 12.67 mm, 29.35 mm, and 0.23. Especially, in mid- or high-latitude regions, the RMSE of the PWV is improved from 10 to 2 mm by changing the inversion in the two-band method to the modified three-band PSW method. Furthermore, the modified three-band PSW results show a better consistency with the radiosonde PWV at any zonal belt and season than the two-band PSW results. This new algorithm could significantly improve the quality of the current FY-2F/VISSR PWV product, especially at sites where the actual PWV are lower than 15 mm.

The role of catheter ablation as an adjunct and alternative to ICD implantation is not known in patients at risk for recurrent ventricular tachycardia (VT) and sudden cardiac death (SCD) across Asia. Patients with nonischemic etiologies of cardiomyopathy, which are highly prevalent in Asia, have not been previously enrolled in randomized trials of VT ablation. To evaluate whether preemptive catheter ablation in patients with monomorphic VT and an indication for ICD implantation results in improved clinical outcomes compared to ICD implantation with standard medical therapy alone. To examine the natural history of ablation outcomes in the absence of background ICD therapy in patients that refuse randomization. The PAUSE-SCD study (NCT02848781) is a prospective, multi-center, randomized controlled trial enrolling patients with structural heart disease (EF

BACKGROUND Variation of atrial electromechanical delay (AED) in early phase after catheter ablation in patients with atrial fibrillation (AF) is lacking. METHODS Fifty-five consecutive patients restored sinus rhythm after ablation was included. Echocardiography was performed at 4 h, 1 day, and 3 days after radiofrequency catheter ablation, and AED was measured simultaneously by echocardiography with pulse Doppler imaging and pulse wave tissue Doppler imaging. RESULTS AED parameters were significantly longer in the nonparoxysmal atrial fibrillation (NPAF) group than in the paroxysmal atrial fibrillation (PAF) group at each checking point after ablation (P

Peripheral blood mononuclear cells (PBMCs) were harvested and reprogramed to induced pluripotent stem cells (iPSCs) from a 46-year-old male patient with familial dilated cardiomyopathy and atrial fibrillation via a non-integrating system. A missense mutation in the LMNA gene (c.1003C > T) was identified by whole-exome sequencing and verified by Sanger sequencing. The pluripotency, differentiation potential, and karyotype of this cell line were also tested. This model is helpful to study the phenotype, mechanism, and therapy for laminopathy.

Human-induced pluripotent stem cell (hiPSC) technology and directed cardiac differentiation technology can provide a continuous supply of cells for disease modeling, drug screening, and cell therapy. However, two-dimensional (2D) cells often fail to faithfully reflect the physiological structure and function of the heart. Considering the contractile function is the most critical and easy-to-understand function of cardiomyocytes, the engineered cardiac tissues (ECT) with mechanical properties may serve as an appropriate three-dimensional (3D) platform for drug evaluation. At present, there are various methods to generate ECTs, some of which are quite costly. In the present study, we proposed that human foreskin fibroblast (HFF) cells, as a cost-effective and accessible cell source, can promote the compaction and remodeling of ECTs. The HFFs derived ECTs displayed stable structural and functional characteristics with a higher performance-to-price ratio. Moreover, both ECTs made from atrial and ventricular cardiomyocytes showed an excellent drug response, demonstrating that the ECT with HFFs as an easy and reliable platform for drug evaluation.

BackgroundIdiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux.ObjectiveTo report a group of idiopathic epicardial VAs remote from the summit and crux areas.MethodsIn total, 9 patients (6 males, mean age 32{plus minus}13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site.ResultsVAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A "QS" type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p

Primary fibrotic atrial cardiomyopathy (PF-ACM) is a novel type of cardiomyopathy characterized by primary atrial fibrosis with arrhythmogenicity and increased stroke risk without ventricular myocardium involvement. However, genetic analysis regarding PF-ACM and genotype-phenotype correlations is lacking. A cohort of PF-ACM patients was recruited and followed up. Whole-exome sequencing (WES) was applied, and genes were screened using a cardiovascular disease (CVD)-related gene panel. Echocardiography and cardiac magnetic resonance (CMR) were performed. The pathogenicity of the identified mutations was evaluated using in silico analysis. Thirty-three unrelated patients were referred for WES. Thirty-three rare variants of 19 CVD-related genes were identified in 21 patients, with 10 patients harboring more than one variation. TTN was the most frequent gene observed. Further analysis demonstrated that variations in sarcomeric (SV) or non-sarcomeric (NSV) genes were found in 16 and 10 patients, respectively. Patients carrying variants regardless of SV or NSV had larger left atrial dimensions determined by echo and larger left atrium areas determined by CMR. There was no discrepancy in disease severity between SV carriers and NSV carriers. Our genetic investigation into PF-ACM has identified several genetic culprits, providing further insight into its underlying pathophysiology and emphasizing a potential role for genetic testing for this condition.

INTRODUCTION Atrial fibrosis is associated with atrial fibrillation (AF) recurrence after ablation. This study aims to determine the relationship between soluble ST2 (sST2), a profibrotic biomarker, and AF recurrence after radiofrequency catheter ablation (RFCA). METHODS AF patients referred for RFCA were consecutively included from October 2017 to May 2019. Baseline characteristics were collected, and sST2 levels were determined before ablation. Left atrial substrate mapping was performed after circumferential pulmonary vein isolation under sinus rhythm, and substrate was modified in low-voltage zones. A second procedure was recommended under recurrence. RESULTS Two hundred fifty-eight patients (146 males, average age 61.0 ± 8.8) were included. After a medium follow-up of 13.5 months, 52 patients (20.2%) had recurrence and received a second procedure. Preoperative sST2 level in patients with recurrence was significantly higher than that in patients without (31.3 ng/mL vs 20.3 ng/mL, P

The superior vena cava (SVC) is the main component of non-pulmonary vein (PV) ectopy in patients with atrial fibrillation (AF). Researchers have found that epicardial adipose tissue (EAT) volume is related to the AF substrate, which can be defined by the low voltage area (LVA). This study aimed to investigate the relationship between SVC-EAT and SVC-AF. Twenty-six patients with SVC-AF triggers were identified as the SVC-AF group. Other three groups were defined and included as the LVA-AF group (LVA5%), non-LVA-AF group (LVA5%), and physical examination (PE) group. EAT around left atrium (LA-EAT) and SVC-EAT volumes were obtained using a cardiac risk assessment module. According to the SVC/LA-EAT ratio, there are significant differences between the SVC-AF group and the three control groups (the SVC-AF group 0.092±0.041

Air Temperature(T air ),a basic meteorological observation element, is an essential meteorological parameter in physiology, hydrology, meteorology, environment, etc. The T air data ,which is characterized by high precision, is of great significance for the greenhouse effect, land surface processes and so on. With the advent of high performing imaging instrument onboard geostationary satellites such as Advanced Geostationary Radiation Imager(AGRI) onboard FY-4A of China, it provides high spatial and temporal resolution data. To estimate T air from such high-resolution data, this paper presents an effective method for estimation T air based on AGRI data. Different machine learning algorithms–-random forest (RF), k-nearest neighbors(KNN) and extreme gradient boosting(XGB)–-are evaluated for estimation of T air under clear sky conditions in the Southwest of China. For the training dataset, the two infrared brightness temperatures of AGRI (BT 12 and BT 13 ), digital elevation model(DEM), latitude and longitude, surface pressure, time and relative humidity(RH) are selected. The T air data obtained by National Centers for Environmental Information(NCEI), evaluates different machine learning algorithm performance in the Southwest of China. The results show that the performance of the XGB model is better than RF and KNN with a correlation coefficient (R) of 0.977, a mean bias of -0.036□,and the root mean square error (RMSE) of 1.266□.

Southern Shaanxi refers to the southwestern part of Shaanxi, and from the west to the east of Shaanxi Province, there are three cities: Hanzhong, Ankang and Shangluo. The annual precipitation data of 8 meteorological stations in the southern part of Shaanxi Province from 1977 to 2017 were selected, and the area was analyzed by EOF (empirical orthogonal function method). The results show that the EOF method can well reveal the temporal and spatial distributions of precipitation field. For the southern part of Shaanxi Province, the first two eigenvectors reveal two typical distribution fields, which are global and eastwest patterns. Its cumulative contribution rate is 79.90%. In general, the eigenvectors of the two fields are expressed as the western region is larger than the eastern region. And high-value centers appear in Hanzhong City. The analysis of the time coefficient corresponding to the eigenvectors shows that the precipitation fields in the southern part of Shaanxi Province mainly show four types. Which includes the wetter in the whole region, the drier in the whole filed, the wetter in west and drier in east, and the wetter in east and drier in west. Compared to the statistical results of 41 year, these results were consistent with the typical precipitation fields

With the global warming, CO (carbon monoxide) as an indirect greenhouse gas, plays a crucial role in the contribution of greenhouse effect. High concentration of CO in the air will do harm to people's health. Based on the CO total column data detected by the Tropospheric Monitoring Instrument (TROPOMI) on Sentinel-5 Precursor satellite, which was launched by the European Space Agency (ESA) on 13 October 2017. This study analyzes the seasonal variable characteristics of the CO total column from June 2018 to May 2019 in China and the spatial distribution of the CO total column in North China, Central China, Sichuan Basin, Qinghai-Tibet Plateau and Pearl River Delta. The high values areas are mainly located in the eastern part of China with high population activity and developed industry, while the Qinghai- Tibet Plateau area and the northwest area are generally low. Selecting the area where the CO total column was significantly enhanced in Hebei province on 24 May, 2018, and monitoring the pollution in the following days. The results show that the TROPOMI data product is a good way to show the source of pollution and has the ability to detect local hot spots.

Sinus node inability or conduction disorders of its surrounding atrial myocardium cause sinus node dysfunction (SND). This study aimed to characterize right atrium (RA) substrates and long-term atrial lead performance after pacemaker implantation in non-senile SND patients.Eighteen SND patients (53.3 ± 9.6 years) controlled by 18 age-matched supraventricular tachycardia patients were consecutively enrolled. The P-wave amplitude (PWA) and P-wave duration (PWD) were measured on surface electrocardiography. Electroanatomic mapping was conducted to assess the bipolar voltage, complex signals, volume, and activation time of RA. Pacemaker implantation was performed in SND patients after mapping.Compared with controls, SND patients showed significant PWA reduction (0.13 ± 0.02 vs. 0.16 ± 0.04 mV, p = 0.017) and PWD prolongation (120.8 ± 15.2 vs. 105.2 ± 8.6 ms, p = 0.001). The RA endocardial voltage was lower (1.56 ± 0.78 vs. 2.57 ± 0.55 mV, p 0.001) and activation time was longer (112.1 ± 14.9 vs. 90.8 ± 12.4 ms, p 0.001) in the study group. Atrial lead was anchored at the lower atrial septum in one patient and failed in another due to extensive atrial scarring. During a median follow-up of 86 (57-88) months, one patient lost atrial capturing, and overall atrial sensing was significantly decreased (2.44 ± 1.16 vs. 1.87 ± 1.01 mV, p = 0.003).Atrial involvement was proved and the process was progressive in non-senile SND patients, as demonstrated by diffused RA lower voltage, slower conduction, and the decrease of the atrial lead sensing.

BACKGROUND Catheter ablation strategies for nonparoxysmal atrial fibrillation (NPAF) are in varied forms. The mechanisms that circumferential pulmonary vein isolation (CPVI) alone could achieve success in some of the patients with NPAF are not well studied. This study sought to assess the clinical outcome of only CPVI approach in NPAF patients without significant left atrium scar. METHODS AND RESULTS A total of 241 consecutive patients with NPAF undergoing an initial ablation procedure were studied. After CPVI, cavotricuspid isthmus ablation and direct current cardioversion, high-density atrial voltage mapping was performed during sinus rhythm. Transitional-voltage zone (TZ) was defined as 0.4-1.3 mV, and low-voltage zone (LVZ) as

The Advanced Geostationary Radiation Imager (AGRI) onboard the first of China's next-generation geostationary meteorological satellite series (FY-4A) can provide high temporal resolution layer precipitable water (LPW) products. The AGRI LPWs, including total precipitable water (TPW), low (PW_low), middle (PW_mid), and high (PW_high) levels precipitable water, were first validated using a year radiosonde data. The results show that AGRI LPWs generally agree well with radiosonde derived LPWs, and the accuracy of LPWs demonstrates obvious spatial and temporal patterns. All LPWs at 00 UTC were underestimated and the root means square error (RMSE) of TPW, PW_low, PW_mid, and PW_high at 00 UTC are 6.04, 1.79, 3.32, and 2.68 mm, while the correlation coefficients (R) are 0.953, 0.958, 0.925, and 0.887, respectively. In contrast, AGRI LPWs at 12 UTC have no obvious under- or over-estimation, and shows a lower RMSE (1.49–4.4 mm) and a higher correlation (0.934–0.971). PW_high shows the largest mean absolute percentage error (MAPE) (>39%), while the MAPE of the other three LPWs is less than 29%. The RMSE of all four AGRI LPWs generally increase with water vapor, while R and MAPE decrease with water vapor. Thus, the AGRI LPWs over low latitudes with high water vapor content show larger RMSE while lower MAPE and R than mid and high latitudes. The accuracy of AGRI LPWs displays a seasonal pattern, with higher RMSE, lower R and MAPE in summer wet months, while lower RMSE, higher R and MAPE in winter dry months.

Introduction Detailed description of longstanding persistent accelerated idioatrial rhythm (AIAR) is lacking. This observational study investigated the clinical manifestations, electrophysiological characteristics, diagnosis, treatment and prognosis of this unusual arrhythmia. Methods and results Fifteen patients (11 males; average age 25.9±15.7 years) suspected with longstanding persistent AIAR were enrolled in our study. All patients had ECG, 24-hour Holter monitoring, isoproterenol provocation test, echocardiogram, and exercise treadmill test. Electrophysiological study (EPS) and catheter ablation were performed if necessary. The above noninvasive tests would be repeated during follow-up. Among the patients, 10 were asymptomatic; 5 had concomitant paroxysmal atrial tachycardia. Two asymptomatic patients had impaired left ventricular function. AIAR was observed throughout 24-hour Holter monitoring, showing chronotropic profile similar to sinus rhythm. Such AIAR exhibited competitive property with sinus rhythm (SR) when provoked by isoproterenol or during treadmill test. Twelve patients had EPS and 8 of them had successful ablation to eliminate AIAR. During a medium follow-up of 3.7 years, all patients were in well clinical course and preserved left ventricular dysfunction, and 3 patients spontaneously reverted to SR at 10-year follow-up. Conclusions Longstanding persistent AIAR is an unusual entity of atrial arrhythmias and in most situations a benign rhythm requiring no treatment. The clinical course will be worsened when AIAR develops rapid focal firing, is associated with focal atrial tachycardias or results in tachycardia-mediated cardiomyopathy, but can be resolved via catheter ablation. This article is protected by copyright. All rights reserved

This paper presents a new atmospheric precipitable water vapor (PWV) retrieval method based on three thermal infrared band observations from geostationary satellites. The proposed method is similar to the traditional physical split-window (PSW) retrieval technique, but a water vapor channel observation near 6.7 μm was included. Sensitivity analyses and simulation retrievals were carried out respectively according to the instrument characteristics of the Stretched Visible and Infrared Spin Scan Radiometer onboard FengYun-2G (SVISSR/FY-2G) and the Moderate Resolution Imaging Spectroradiometer aboard Terra (MODIS/Terra). The results indicate that the proposed 3-band algorithm can significantly reduce PWV retrieval errors caused by surface emissivity uncertainty and observation errors, especially in dry atmospheric conditions (i.e., PWV 2 ), root mean square error (RMSE), and bias between the SVISSR retrieved PWV and the radiosonde PWV are 0.87, 0.43 cm and 0.14 cm, respectively. The R 2 , RMSE and bias of the MODIS retrieved PWV are 0.89, 0.10 cm and − 0.042 cm, respectively, which are slightly better than the MODIS L2 thermal infrared and near-infrared PWV products.

Several satellites have been launched to monitor the increasing concentrations of greenhouse gases, especially CO2 and CH4 in the atmosphere, through back-scattered hyperspectral radiance in the shortwave infrared (SWIR) band. The vertical profiles of greenhouse gases and aerosol could strongly affect the results from these instruments. To investigate the effects of the vertical distribution of CO2 on uncertainty in SWIR satellite retrieval results, we conducted observations of the vertical profiles of CO2, CH4, and aerosol particles at 0.6–7 km above sea level using a Beechcraft King Air 350ER in Jiansanjiang (46.77° N, 131.99° E), Heilongjiang province, Northeast China, on August 7–12, 2018. The profiles from this aircraft captured a decrease in CO2 from 2 km to the minimum altitude due to uptake from vegetation at the surface in summer. CH4 measurements showed an average 0.5 ppm increase from 2.0 to 0.6 km, which may result from emissions from the large area of paddy fields below, and a constant mole fraction between 1.951 and 1.976 ppm was recorded at 2 km and above. Comparison of CO2 profiles from a new version of the carbon cycle data assimilation system Tan-Tracker (v1), retrievals from OCO-2 and aircraft measurements was conducted. The results from OCO-2 and the assimilation model system Tan-Tracker captured the vertical structure of CO2 above 3 km, whereas below 3 km, the values from OCO-2 and Tan-Tracker model were lower than those from in situ measurements. Column-averaged CO2 volume mixing ratios calculated from in situ measurements showed biases of −2.39 ± 2.02 ppm and −0.61 ± 0.49 % compared to OCO-2 retrievals.

Metamorphic rock reservoirs are special reservoirs that are quite different from traditional sedimentary rock reservoirs and contain rich hydrocarbon reserves. However, their lithofacies characteristics and reservoir properties are relatively underexplored, and the key factor in reservoirs is lithofacies. Based on core samples, thin sections, whole-rock analysis and well-log and seismic data, we evaluated the lithologies, petrological characteristics and reservoir properties of metamorphic rocks and then explored the main factors controlling reservoir formation and metamorphic rock quality in the Aryskum depression, South Turgay Basin, Kazakhstan. In this area, four types of lithofacies are identified: granitic gneiss (high DEN and CN, low GR), leptite (high GR and CN), gabbro (low GR and CN) and granite (high GR and low CN); among these rocks, granitic gneiss is widely distributed. The reservoir spaces of metamorphic rocks are divided into fractures and pores produced via metamorphism and structural movements. Fractures can be subdivided into structural fractures (SFs), dissolution fractures (DFs), cleavage microfissures (CMfs) and microfissures (Mfs), and pores include dissolved intergranular pores (DInterPs), dissolved intragranular pores (DIntrPs) and vugs (Vgs). Numerous SFs and DFs provide the main reservoir spaces for hydrocarbons. The reservoir quality of metamorphic rocks is primarily controlled by faults, fractures, lithofacies, minerals, dissolution and paleogeomorphology. Lithofacies and minerals are the internal factors that control dissolution and fragmentation, while paleogeomorphology and faults are the external factors that control fracture development. Leptite and granitic gneiss are high-quality reservoir lithofacies, and high paleogeomorphology areas and fault zones are the optimal locations for fractures and pores. Reservoir spaces undergo a series of repeated changes from formation to development, filling and reformation, and a comprehensive reservoir evolution model is proposed to illustrate the distribution of high-quality reservoirs. This study has scientific significance for investigating the reservoir-forming mechanisms of metamorphic rocks and practical applications for exploring and developing oil and gas fields in areas with metamorphic rocks.