Efficacy and safety of pulsed field ablation for accessory pathways: a pilot study.

AIMS: Radiofrequency ablation is used as a first-line therapy for accessory pathways (APs). However, data regarding the effects of pulsed field ablation (PFA) on APs are limited. We sought to evaluate the acute procedural and 6-month success and safety of PFA in a cohort of patients with APs. METHODS AND RESULTS: A focal contact force-sensing PFA catheter was used for patients with APs. Pulsed field ablation generator generated a bipolar and biphasic waveform (±1000 V) with a duration of 100 ms from the tip of the PFA catheter. A 100% acute procedural success was achieved in 10 conscious patients with APs (7 left anterolateral, 2 left inferolateral, and 1 right posteroseptal APs) including 6 (60%) patients after an initial application. The average total ablation time was 6.3 ± 4.9 s for 4.7 ± 1.8 ablation sites (ASs), including 3.1 ± 2.4 s at targets and 3.2 ± 2.9 s at 3.2 ± 2 bolus ASs. The mean skin-to-skin time was 59.3 ± 15.5 min, and PFA catheter dwell time was 29.4 ± 7.8 min. One patient encountered transient sinus arrest during PFA due to parasympathetic overexcitation. Sinus rhythm was restored in all patients without any significant adverse events during the short-term follow-up. CONCLUSION: Pulsed field ablation of APs was feasible, effective, and safe. Its efficiency was remarkable for its ultrarapid termination of AP conduction. Further studies are warranted to prove whether utilization of PFA with current parameters can extend to manifold AP ablation.

Geographic distribution of bacterial communities of inland waters in China.

Microorganisms are integral to freshwater ecological functions and, reciprocally, their activity and diversity are shaped by the ecosystem state. Yet, the diversity of bacterial community and its driving factors at a large scale remain elusive. To bridge this knowledge gap, we delved into an analysis of 16S RNA gene sequences extracted from 929 water samples across China. Our analyses revealed that inland water bacterial communities showed a weak latitudinal diversity gradient. We found 530 bacterial genera with high relative abundance of hgcI clade. Among them, 29 core bacterial genera were identified, that is strongly linked to mean annual temperature and nutrient loadings. We also detected a non-linear response of bacterial network complexity to the increasing of human pressure. Mantel analysis suggested that MAT, HPI and P loading were the major factors driving bacterial communities in inland waters. The map of taxa abundance showed that the abundant CL500-29 marine group in eastern and southern China indicated high eutrophication risk. Our findings enhance our understanding of the diversity and large-scale biogeographic pattern of bacterial communities of inland waters and have important implications for microbial ecology.

Impact of left atrial appendage orifice diameter on the safety and efficacy of left atrial appendage closure using the LAmbre device.

BACKGROUND: The diameter and shape of the left atrial appendage (LAA) orifices may influence occluder selection and the outcomes of left atrial appendage closure (LAAC) procedure. This study aimed to evaluate the impact of LAA orifice diameter on the safety and efficacy of LAAC using the LAmbre device. METHODS: A total of 133 patients with nonvalvular atrial fibrillation (AF) who underwent LAAC with the LAmbre device between June 2018 and June 2020 were included in this study. The patients were categorized into two groups based on the maximal diameter of the LAA orifice: the large LAA group (n = 45) with a maximal orifice diameter of ≥31 mm, and the normal LAA group (n = 88) with a maximal orifice diameter of <31 mm. The study assessed periprocedural characteristics and long-term clinical follow-up. RESULTS: Successful implantation of the LAmbre device was observed in all patients. The incidence of periprocedural peridevice leakage (PDL) was significantly higher in the large LAA group (P < 0.001), while the incidence of acute pericardial effusion (PE) during the procedure was comparable between the two groups (P = 1.000). After a mean follow-up period of 4.8 ± 1.7 years, three patients in the large LAA group developed delayed PE, while no patients in the normal LAA group did (P = 0.037). Additionally, a larger LAA maximal orifice diameter was associated with a higher prevalence of PDL (P = 0.001) and PE (including both acute and delayed PE) (P = 0.027). The optimal cutoff value of the LAA maximal orifice diameter for predicting PDL and PE after LAAC with the LAmbre device was determined to be 30 mm. CONCLUSION: The findings suggest that the LAmbre device is a safe and feasible option for occluding the LAA, regardless of its orifice diameter. However, it is important to note that a larger LAA orifice diameter may increase the risk of PDL and delayed PE.

Delayed pericardial effusion or tamponade following left atrial appendage closure: A single-center experience.

BACKGROUND: Pericardial effusion or pericardial tamponade (PE/PT) is a relatively common complication of left atrial appendage closure (LAAC). However, delayed PE/PT is rare with limited data. The aim of the study was to analyze the incidence and clinical consequences of delayed PE/PT following LAAC. METHODS: Patients with nonvalvular AF who were successfully implanted with LAAC devices from October 2014 to April 2021 were consecutively screened. Subjects experiencing delayed PE/PT after LAAC were included. All treatment sessions of the subjects were recorded in detail. After discharge, the patients were followed up for clinical outcomes. RESULTS: A total of 748 patients with successful LAAC [nitinol cage device (475 Watchman 2.5), nitinol plug device (131 ACP and 142 LAmbre)] were screened. Six patients experienced delayed PE/PT (1 Watchman, 2 ACP, 3 LAmbre). The incidence of delayed PE/PT was higher in patients with a nitinol plug device (1.8% vs. 0.2%, P = 0.027). Bloody PE only occurred in patients with a nitinol plug device (5/273, 1.8%). All the patients accepted pericardiocentesis and discontinuing antithrombotic medication, and none of the patients died or needed cardiac surgery. All patients were followed up for 810 (598, 1174) days after discharge. None of them developed constrictive pericarditis or thromboembolic or major bleeding events. CONCLUSION: Delayed PE/PT is rare but can occur, and the incidence of delayed bloody PE/PT for the nitinol plug device was higher than that for the nitinol cage device. The strategy of emergency pericardiocentesis combined with discontinuing antithrombotic medication may be effective for delayed bloody PE/PT.

Correlation between Serum Myosin Light Chain 4 Levels and Recurrence after Radiofrequency Ablation in Patients with Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia that is harmful to human health. This study aims to explore the relationship between myosin light chain 4 (MYL4) and AF recurrence after radiofrequency ablation (RFA). Patients with AF (n = 85) were enrolled, and healthy subjects (n = 90) with normal sinus rhythm and no previous history of AF were selected as controls. The serum levels of MYL4, transforming growth factor (TGF) -ß1, and procollagen type-I C-terminal propeptide (PICP) were determined. The correlation between MYL4 and atrial fibrosis remodeling indicators (TGF-ß1/PICP) and left atrial diameter (LAD) was analyzed. The influence of MYL4 on AF recurrence after RFA was evaluated, and the independent correlation between them was assessed. Patients with AF and the controls showed no significant differences in age, gender, body mass index, systolic blood pressure, diastolic blood pressure, left ventricular ejection fraction, triglycerides, total cholesterol, high-density lipoprotein, low-density lipoprotein, white blood cell count, neutrophil/lymphocyte ratio, brain natriuretic peptide, and history of smoking, drinking, hypertension, and diabetes (P > 0.05), but with increased LAD in patients with AF (P < 0.01). Serum MYL4 level was reduced in patients with AF (0.6 ± 0.2) compared with that of controls (0.1 ± 0.6) (P < 0.01), and it was negatively correlated with TGF-ß1, PICP, and LAD (r = -0.2389, P < 0.05; r = -0.5174, P < 0.01; r = -0.3191; P < 0.01). Low levels of MYL4 increased the risk of AF recurrence after RFA (χ2 = 16.64; P < 0.0001). A low MYL4 level in patients with AF showed a poorer prognosis. Serum MYL4 level and AF type were independent risk factors affecting AF recurrence after RFA.

Safety and efficacy of low-dose non-vitamin K antagonist oral anticoagulants versus warfarin after left atrial appendage closure with the Watchman device.

BACKGROUND/PURPOSE: Anticoagulant therapy is suggested within 45 days after Watchman device implantation for stroke prevention in patients with atrial fibrillation (AF). A previous study demonstrated that non-vitamin K antagonist oral anticoagulants (NOACs) were a feasible peri- and postprocedural alternative to warfarin. The present study aimed to compare the safety and efficacy of using different anticoagulants (low-dose NOACs vs. warfarin) within 45 days after Watchman device implantation in a Chinese population. METHODS: Patients with successful Watchman device implantation from October 2014 to June 2020 were included. All patients received anticoagulants within 45 days after the procedure, and those patients were divided into three groups according to the type of postprocedural anticoagulants. Transesophageal echocardiography follow-up was performed 45 days post procedure to assess residual flow and the occurrence of device-related thrombus (DRT). RESULTS: A total of 368 patients were enrolled in the study. The study population was divided into three groups: the warfarin group (n = 77), the dabigatran group (n = 165) and the rivaroxaban group (n = 126). Periprocedural major bleeding was higher in the warfarin group (2.6% vs. 0% vs. 0%, P = 0.043), while minor bleeding was comparable among the groups (3.9% vs. 1.2% vs. 0.8%, P = 0.230). No periprocedural transient ischemic attack/stroke occurred. At follow-up, the incidence of DRT was higher in the warfarin group than in the other groups (4.2% vs. 0.6% vs. 0.8%; P = 0.116), but the difference was not statistically significant. The rates of thromboembolic and bleeding events were similar in the three groups. CONCLUSION: The safety and efficacy of low-dose dabigatran and rivaroxaban were comparable to those of warfarin within 45 days after Watchman device implantation in a Chinese population.

Matrine attenuates cardiomyocyte ischemia-reperfusion injury through activating AMPK/Sirt3 signaling pathway.

Matrine has been found to affect cell viability and function. In the present study, we explored the cardioprotective role of matrine in cardiomyocyte damage under hypoxia/reoxygenation. In vitro, cardiomyocyte hypoxia/reoxygenation was used to mimic ischemia/reperfusion injury in the presence of matrine. After exposure to hypoxia/reoxygenation, cardiomyocyte viability was reduced and cell apoptosis was increased; this alteration was inhibited by matrine. At the molecular levels, Sirt3 and AMPK were significantly downregulated by hypoxia/reoxygenation injury whereas matrine administration was able to upregulate Sirt3 and AMPK expression and activity in the presence of hypoxia/reoxygenation. Interestingly, inhibition of Sirt3/AMPK pathway abolished the cardioprotective action of matrine on cardiomyocyte in the presence of hypoxia/reoxygenation injury, resulting into cardiomyocyte viability reduction and cell death augmentation. Altogether, our results demonstrated a novel role played by matrine in regulating cardiomyocyte viability and death in the presence of hypoxia/reoxygenation, with a potential application in the clinical practice for the treatment of patients with myocardial infarction.

LPS induces cardiomyocyte necroptosis through the Ripk3/Pgam5 signaling pathway.

Necroptosis is a new type of cell death. However, the role of necroptosis in LPS-related cardiomyocyte damage has not been fully understood. The aim of our study is to explore the molecular mechanism underlying inflammation-mediated cardiomyocyte necroptosis. H9C2 cardiomyocyte cell line was treated with LPS. Then, cell viability and necroptosis were measured through qPCR and ELISA. Pathway analysis was performed to verify whether Ripk3/Pgam5 signaling pathway is implicated into the regulation of cardiomyocyte necroptosis. The results demonstrated that LPS reduced cardiomyocyte viability and activated necroptosis. At the molecular levels, oxidative stress and inflammation were triggered by LPS and these alterations may contribute to the activation of necroptosis. Finally, we found that Ripk3/Pgam5 signaling pathway was activated by LPS in cardiomyocyte and this signaling pathway may explain the regulatory mechanism underlying LPS-mediated necroptosis. Altogether, our results demonstrated that septic cardiomyopathy is associated with an activation of necroptosis through the Ripk3/Pgam5 signaling pathway.

Metabolic syndrome, high-sensitivity C-reactive protein levels and the risk of new-onset atrial fibrillation: Results from the Kailuan Study.

BACKGROUND AND AIMS: Some studies have reported that metabolic syndrome (MS) and a high inflammatory state are risk factors for atrial fibrillation (AF). However, the combined effect of MS and a high inflammatory state on AF is still unknown. We aimed to investigate the association of MS and high-sensitivity C-reactive protein (hs-CRP) levels with the risk of AF in a large community-based population. METHODS AND RESULTS: A total of 81,092 subjects from the Kailuan Study with electrocardiogram examination and hs-CRP data at baseline (1st examination, 2006-2007) were included in this study. The enrolled population was divided into 4 groups according to the presence or absence of metabolic syndrome and high hs-CRP (>3 mg/L). The follow-up examinations were performed every two years (2nd examination, 2008-2009; 3rd examination, 2010-2011; 4th examination, 2012-2013; 5th examination, 2014-2015). All participants were followed until the occurrence of AF or the date of the last examination. After a mean time of 7.2 ± 2.0 years, a total of 271 individuals developed incident AF. MS or high hs-CRP alone was not associated with incident AF after multivariable adjustment. However, multiple Cox regression analysis showed that subjects with MS and hs-CRP > 3 mg/L had a greater risk for AF than those without MS and with hs-CRP ≤ 3 mg/L (hazard ratio, 1.61; 95% confidence interval 1.08-2.41; P = 0.019). CONCLUSION: MS combined with a high hs-CRP level is associated with an increased risk for AF in the Chinese population. However, the mechanism is unknown and awaits further study. TRIAL REGISTRATION SITE: http://www.chictr.org.cn/index.aspx. REGISTRATION NUMBER: ChiCTR-TNRC-11001489.

Percutaneous Left Atrial Appendage Closure Confirmed by Intra-Procedural Transesophageal Echocardiography under Local Anesthesia: Safety and Clinical Efficacy.

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) is usually performed under general anesthesia (GA) guided by transesophageal echocardiography (TEE), or under local anesthesia (LA) guided by intracardiac echocardiography (ICE). GA is known to carry some disadvantages. It is sometimes technically challenging to obtain adequate imaging of the left atrial appendage (LAA) with LAAC guided by ICE. This study aimed to assess the safety and clinical efficacy of LAAC guided by TEE under LA in patients with non-valvular atrial fibrillation (AF). METHODS: A total of 159 patients (70.5 ± 8.2 years; 66% male) with AF who had a high risk of stroke and bleeding or who had contraindications for oral anticoagulation underwent LAAC under LA. TEE or computed tomography (CT) follow-up was scheduled approximately 6 weeks after the procedure. Patients were followed to assess ischemic stroke and major bleeding events. RESULTS: The LAA was successfully occluded in 152 patients (95.6%). There were 2 (1.3%) periprocedural major adverse events. A total of 142 patients (93.4%) finished TEE or CT follow-up. Thrombus formation as seen on the device was documented in 2 patients. All of the LAAs were completely sealed with the absence of flow or with minimal flow. The median follow-up period was 522 days, resulting in a total of 216 patient-years. Ischemic stroke occurred in 4 patients. The annual ischemic stroke rate was 1.9/100 person-years. Major bleeding occurred in 2 patients. The annual major bleeding rate was 1.9/100 person-years. CONCLUSIONS: In this study, percutaneous LAAC using TEE under LA was safe and showed encouraging results for stroke prevention and major bleeding reduction.

Keystone taxa of water microbiome respond to environmental quality and predict water contamination.

The human activity introduces strong environmental stresses, and results in great spatiotemporal heterogeneity for the environment. Although the effects of environmental factors on the microbial diversity and succession have been widely studied, knowledge about how keystone taxa respond to environmental stresses remains poorly understood. We examined bacterial and archaeal communities from 45 wetland ponds covering a wide range of waters in Hangzhou. We found that shifts in bacterial and archaeal communities were strongly correlated with water pollution as indicated by the comprehensive water quality identification (CWQI). The SEGMENTED analysis suggested that there were non-linear responses of microbial communities and keystone taxa to the water pollution gradient. Moreover, these significant tipping points (e.g., CWQI > 4.0) would afford a warning line for urban wetland management. Notably, keystone taxa of bacterial communities could be used to successfully (~88.9% accuracy) predict water contamination levels. This study provides new insights into the potential for keystone bacterial taxa to predict water contamination.

Left atrial appendage closure with zero fluoroscopic exposure via intracardiac echocardiographic guidance.

BACKGROUND/PURPOSE: Left atrial appendage closure (LAAC) is conventionally guided by fluoroscopy and transesophageal echocardiography. We introduce an LAAC technique without fluoroscopy exposure using intracardiac echocardiography (ICE) and electroanatomic mapping system (EAMS) under local anesthesia. METHODS: Seven non-valvular atrial fibrillation patients who underwent LAAC with the LAmbre devices under the ICE and EAMS guidance were compared to 7 patients following the conventional approach by propensity score matching. ICE probe was advanced into the left atrium (LA) to guide sizing and device implantation following the orthogonal tri-axial technique (Axis-X: from left pulmonary veins [PVs] to LAA; Axis-Y: from right PV ostium to LAA; Axis-Z: from lower LA to LAA). RESULTS: The mean diameters of ostia and landing zone were 21.4 ± 3.9 mm and 20.4 ± 4.2 mm, respectively. LAmbre devices with a mean umbrella diameter of 23.7 ± 4.2 mm and cover disc diameter of 29.4 ± 3.6 mm were successfully implanted and acute complete LAA sealing without peri-device leak (PDL) were achieved in all cases. Neither fluoroscopy exposure nor contrast consumption was recorded. No procedure related complications were documented. The mean procedural time and PDLs at follow-ups were comparable to those in the conventional group. No stroke or thromboembolic events were documented. CONCLUSION: The fluoroscopy exposure could be minimized, even to zero, in the ICEguided LAAC procedures feasibly and safely using LAmbre devices. The orthogonal triaxial technique is considered efficacious and safe for the procedures.

Combination of left atrial appendage closure and catheter ablation in a single procedure for patients with atrial fibrillation: Multicenter experience.

BACKGROUND/PURPOSE: Experience in procedures combining left atrial appendage (LAA) closure (LAAC) and catheter ablation (CA) was scarce in Chinese nonvalvular atrial fibrillation (AF) patients with high risks for stroke and bleeding. We aimed to investigate the efficacy and safety of the combination therapy with LAAC and AF CA in a single procedure based on the multicenter data and medium-term follow-up results. METHODS: A total of 122 AF patients with a mean CHA2DS2-VASc score of 4.3 ± 1.4 and HAS-BLED score of 3.3 ± 1.0 were enrolled. The Watchman (n = 83) devices were implanted either before or after AF ablations in the same procedure, while the Amplatzer Cardiac Plug (ACP, n = 39) devices were implanted immediately after CA. AF recurrence and transesophageal echocardiography results were evaluated. RESULTS: All devices were successfully implanted and acute complete LAA occlusions were achieved in 115 (94.3%) of patients. Neither acute nor chronic peri-device leaks greater than 5 mm were detected. Oral anticoagulation was held in all patients but two with asymptomatic device-related thrombi, which were resolved after prolonged anticoagulation. AF-free success rate without antiarrhythmic drugs was 76.2% after a mean follow-up of 11.5 ± 6.8 months. No serious complications were observed during the follow-up. CONCLUSION: The combination therapy with LAAC and AF ablation in a single procedure was efficacious and safe in the Chinese symptomatic AF population with high risk for stroke and bleeding.

Association of Left Atrial Appendage Voltage with Ischemic Stroke in Patients with Atrial Fibrillation.

BACKGROUND: Low atrial voltage is associated with an increased risk of stroke. The relationship between left atrial appendage voltage (LAAV) and ischemic stroke remains unknown. Low LAAV may predict the prevalence of ischemic stroke in patients with atrial fibrillation (AF). METHODS: A total of 1108 patients with AF referred for catheter ablation were consecutively included from January 2015 to May 2018. The patients were divided into stroke and control groups based on previous ischemic stroke by neuroimaging criteria. LAAV was measured with a circular mapping catheter in sinus rhythm after ablation. Variables were compared, and logistic regression was performed to assess the relationship between LAAV and stroke. RESULTS: A total of 120 patients (10.8%) had a history of ischemic stroke. The patients in the stroke group were older and had higher percentages of hypertension, diabetes mellitus and coronary/vascular disease. The CHA2DS2-VASc score was higher and left atrial diameter was larger in the patients with stroke. More left atrial appendage thrombi and spontaneous echo contrast were detected in the stroke group. LAAV was significantly lower in the stroke group compared with the controls (5.3 ± 1.8 mV vs. 6.5 ± 1.8 mV; p < 0.001). Multivariate logistic regression revealed that a lower LAAV was associated with increased stroke prevalence [odds ratio = 0.75; 95% confidence interval (CI) 0.65-0.87; p < 0.001]. LAAV had a predictive value, with an area under the curve of 0.83 (95% CI 0.79-0.87; p < 0.001). With an optimal cut-off value of 5.2 mV for LAAV, the sensitivity and specificity were 75% and 74%, respectively. CONCLUSIONS: Lower LAAV in AF patients was associated with increased ischemic stroke prevalence. Whether LAAV is related to incident stroke requires further studies.

Optimal combination strategy of left atrial appendage closure plus catheter ablation in a single procedure in patients with nonvalvular atrial fibrillation.

BACKGROUND: The efficacy and safety of combining left atrial appendage closure (LAAC) plus atrial fibrillation (AF) catheter ablation (CA) in a single procedure has been established, but the optimal combination strategy has not been thoroughly elucidated to date. OBJECTIVE: We aimed to investigate the impact of different combination strategies on clinical outcomes. METHODS: Eighty-two consecutive patients with symptomatic AF (mean CHA2 DS2 -VASc score 4.4 ± 1.4, mean HAS-BLED score 3.5 ± 1.0) were enrolled. LAAC with the Watchman device was performed either before (occlusion-first group, N  =  52) or after (ablation-first group, N  =  30) CA. Procedural and clinical data were retrospectively analyzed to evaluate the advantages of each strategy. RESULTS: Complete device occlusions were achieved in 92.3% and 90.0% of patients, respectively (P  =  0.719). Neither acute nor chronic peridevice leak greater than 5 mm was detected. Oral anticoagulants were held in all patients, except two (one in each group) with asymptomatic device-related thrombi. AF-free success rates were comparable between groups with a mean follow-up of 11.2 ± 7.3 months (75.0% vs. 70.0%, log-rank P  =  0.311). The new peridevice leak rate was significantly lower in the occlusion-first group (7.7% vs. 26.7%, P  =  0.019). Multivariate logistic regression demonstrated that the combination strategy was independently associated with the new peridevice leak (P  =  0.025, OR 13.3). CONCLUSIONS: Both occlusion-first and ablation-first strategies were efficacious and safe as combined procedures in patients with nonvalvular AF; however, the occlusion-first strategy was associated with lower new peridevice leak rates at follow-up.

Gender-Related Association of Serum Uric Acid Levels with Premature Ventricular Contraction.

In this study, we aim to investigate the association of serum uric acid (SUA) with the prevalence of premature ventricular contraction (PVC). The relationship between SUA and the prevalence of PVC in 98,965 subjects (79,034 male subjects, mean age: 51.9 ± 12.6 years old) in the Kailuan cohort study (n = 101,510, age range: 18-98 years) from June 2006 to October 2007 was investigated. These subjects were divided into five groups on the basis of their SUA levels. A multivariate logistic regression model was constructed to evaluate the association between SUA and the prevalence of PVC. The prevalence of PVC was 1.1% in all subjects, 1.1% in male subjects, and 1.0% in female subjects. Compared with the first quintile of SUA, the odds ratio (OR) and 95% confidence interval (95% CI) of other quintiles were 1.33 (1.05-1.69), 1.14 (0.90-1.46), 1.37 (1.08-1.74), and 1.63 (1.30-2.06) in male subjects; 1.12 (0.68-1.87), 1.27 (0.77-2.09), 1.45 (0.90-2.36), and 1.33 (0.81-2.18) in female subjects; and 1.30 (1.04-1.61), 1.20 (0.96-1.50), 1.33 (1.07-1.66), and 1.57 (1.26-1.95) for all subjects. The correlation between SUA and the prevalence of PVC was significant in all subjects and in male subjects, but not in female subjects. We demonstrated that SUA was apparently associated with the prevalence of PVC. The significant relationship between SUA and PVC identified in male subjects suggests the potential involvement of a gender-specific mechanism. Prospective studies are needed to further corroborate our results.

A New Formula for Estimating the True QT Interval in Left Bundle Branch Block.

INTRODUCTION: QT prolongation is an independent risk factor for cardiac mortality. Left bundle branch block (LBBB) is more common in patients as they age. Widening of the QRS in LBBB causes false QT prolongation and thus makes true QT assessment difficult. We aimed to develop a simple formula to achieve a good estimate of the QT interval in the presence of LBBB. METHODS AND RESULTS: To determine the effect of QRS duration on the QT interval, QRS and QT were measured in sinus rhythm and during right ventricular apical pacing in 62 patients (age 55 ± 11 years, 60% male) undergoing electrophysiology studies. A QT formula for LBBB (QT-LBBB) was derived based on the effect of increased QRSLBBB on QTLBBB . The predictive accuracy of the QT-LBBB formula was then tested in 22 patients (age 66 ± 13 years, 64% male) with intermittent LBBB with comparisons to prior QT formulae and JT index. On average, the net increase in QRSLBBB constituted 92% of the net increase in QTLBBB . A new formula, QT-LBBB = QTLBBB - (0.86 * QRSLBBB - 71), which takes the net increase in QRSLBBB into account, best predicted the QT interval with heart rate corrected QTc in the test set of LBBB ECGs when compared to the baseline value and prior formulae. CONCLUSION: The QT-LBBB formula developed in this study best estimates the true QT interval in the presence of LBBB. It is simple and therefore can be easily utilized in clinical practice.

Clinical outcomes of combined catheter ablation and left atrial appendage closure in elderly patients with nonvalvular atrial fibrillation.

BACKGROUND: Catheter ablation (CA) combined with left atrial appendage closure (LAAC) has emerged as a promising method to relieve symptoms while reducing the incidence of stroke in selected high-risk patients with atrial fibrillation (AF). HYPOTHESIS: We aimed to investigate the clinical outcomes of combined CA and LAAC in elderly patients. METHODS: A total of 316 patients with symptomatic drug-refractory AF who underwent combined CA and LAAC between January 2016 and December 2020 were retrospectively included. Baseline characteristics, periprocedural complications, and clinical events during follow-up were recorded and compared between patients aged ≥ 75 years (n = 66) and <75 years (n = 250). RESULTS: Pulmonary vein isolation and satisfactory LAAC were achieved in all patients. No patients experienced death or stroke/transient ischemic stroke periprocedurally. After a median follow-up of 12.2 (6.7-24.4) months and 11.9 (5.5-23.6) months, the rate of sinus rhythm maintenance was comparable between the two groups (≥75 years: 78.8% vs. <75 years: 80.8%; log-rank test, p = 0.674). The median follow-up periods for clinical outcomes were 27.9 (9.3-44.8) months and 25.2 (10.8-45.7) months, respectively. In patients aged ≥ 75 years, one suffered ischemic stroke, and one experienced major bleeding event. In patients aged < 75 years, four had ischemic stroke, and eight had major bleeding events. Two patients aged < 75 years died during follow-up, while none of the patients aged ≥ 75 years died. CONCLUSIONS: Combining CA and LAAC was feasible, safe and effective in elderly patients with AF.

Relationship of inflammatory indices with left atrial appendage thrombus or spontaneous echo contrast in patients with atrial fibrillation.

BACKGROUND: Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation (AF). The data about the relationship between inflammatory indices and left atrial appendage thrombus (LAAT) or dense spontaneous echo contrast (SEC) are limited. AIM: To explore the value of inflammatory indices for predicting the presence of LAAT or dense SEC in nonvalvular AF patients. METHODS: A total of 406 patients with nonvalvular AF who underwent transesophageal echocardiography were included and divided into two groups based on the presence (study group) or absence (control group) of LAAT or dense SEC. Inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), were calculated from complete blood analysis. The associations of inflammatory indices with LAAT/dense SEC were analyzed using logistic regression. RESULTS: LAAT and dense SEC were detected in 11 (2.7%) and 42 (10.3%) patients, respectively. The PLR only showed an association with LAAT/dense SEC in the univariate model. Elevated NLR (odds ratio [OR] = 1.48, 95% confidence interval [CI]: 1.11-1.98, P = 0.007) and reduced LMR (OR = 0.59, 95%CI: 0.41-0.83, P = 0.003) were found to be independent risk factors for the presence of LAAT/dense SEC. The areas under the NLR and LMR curves for predicting LAAT/dense SEC were 0.73 (95%CI: 0.66-0.80, P < 0.001) and 0.73 (95%CI: 0.65-0.81, P < 0.001), respectively, while the cutoff values were 2.8 (sensitivity: 69.8%; specificity: 64.0%) and 2.4 (sensitivity: 71.7%; specificity: 60.6%), respectively. CONCLUSION: Increased NLR and decreased LMR may predict LAAT/dense SEC in patients with nonvalvular AF.

Left atrial appendage closure in patients with left atrial appendage thrombus guided by intracardiac echocardiography.

BACKGROUND: Data regarding left atrial appendage closure (LAAC) in patients with left atrial appendage (LAA) thrombus are limited. Recently published cases have mostly been guided by transesophageal echocardiography. Intracardiac echocardiography (ICE) is now widely used during LAAC procedures. OBJECTIVE: This is the first study to report the feasibility of LAAC in patients with LAA thrombus guided by ICE. METHODS: Patients with persistent LAA thrombus despite anticoagulation or contraindications to anticoagulation who underwent a modified ICE-guided LAAC procedure between June 2021 and April 2023 were included. Periprocedural events and clinical outcomes during follow-up were recorded. RESULTS: A total of 12 patients (mean age 65 ± 7 years; 92% male) were included: 10 with persistent LAA thrombus and 2 with contraindications to anticoagulation. Most of the thrombus was at the apex (n = 6), followed by the body (n = 3) and the ostium (n = 3). A LAmbre device was used and successfully implanted in all patients with the guidance of ICE. No thrombotic material was retrieved from patients with the protection of cerebral protection device (n = 11). No patient experienced severe periprocedural complications. All patients completed transesophageal echocardiography follow-up, and no device-related thrombus or peridevice leak > 3 mm was detected. None of the patients experienced stroke/transient ischemic attack, systemic embolism, or major bleeding events during a median follow-up of 147 days (interquartile range 80-306 days). CONCLUSION: LAAC using the LAmbre device guided by ICE may be feasible in patients with LAA thrombus when performed by experienced operators.