LSTM Short-Term Wind Power Prediction Method Based on Data Preprocessing and Variational Modal Decomposition for Soft Sensors.

Soft sensors have been extensively utilized to approximate real-time power prediction in wind power generation, which is challenging to measure instantaneously. The short-term forecast of wind power aims at providing a reference for the dispatch of the intraday power grid. This study proposes a soft sensor model based on the Long Short-Term Memory (LSTM) network by combining data preprocessing with Variational Modal Decomposition (VMD) to improve wind power prediction accuracy. It does so by adopting the isolation forest algorithm for anomaly detection of the original wind power series and processing the missing data by multiple imputation. Based on the process data samples, VMD technology is used to achieve power data decomposition and noise reduction. The LSTM network is introduced to predict each modal component separately, and further sum reconstructs the prediction results of each component to complete the wind power prediction. From the experimental results, it can be seen that the LSTM network which uses an Adam optimizing algorithm has better convergence accuracy. The VMD method exhibited superior decomposition outcomes due to its inherent Wiener filter capabilities, which effectively mitigate noise and forestall modal aliasing. The Mean Absolute Percentage Error (MAPE) was reduced by 9.3508%, which indicates that the LSTM network combined with the VMD method has better prediction accuracy.

Phase Error Reduction for a Structured-Light 3D System Based on a Texture-Modulated Reprojection Method.

Fringe projection profilometry (FPP), with benefits such as high precision and a large depth of field, is a popular 3D optical measurement method widely used in precision reconstruction scenarios. However, the pixel brightness at reflective edges does not satisfy the conditions of the ideal pixel-wise phase-shifting model due to the influence of scene texture and system defocus, resulting in severe phase errors. To address this problem, we theoretically analyze the non-pixel-wise phase propagation model for texture edges and propose a reprojection strategy based on scene texture modulation. The strategy first obtains the reprojection weight mask by projecting typical FPP patterns and calculating the scene texture reflection ratio, then reprojects stripe patterns modulated by the weight mask to eliminate texture edge effects, and finally fuses coarse and refined phase maps to generate an accurate phase map. We validated the proposed method on various texture scenes, including a smooth plane, depth surface, and curved surface. Experimental results show that the root mean square error (RMSE) of the phase at the texture edge decreased by 53.32%, proving the effectiveness of the reprojection strategy in eliminating depth errors at texture edges.

[Bibliometrics Analysis of Studies on Hypertrophic Cardiomyopathy From 2018 to 2022].

Objective To analyze the research progress and hot topics in hypertrophic cardiomyopathy from 2018 to 2022.Methods The publications in the field of hypertrophic cardiomyopathy from January 1,2018 to December 31,2022 were retrieved from Web of Science core collection database and included for a bibliometric analysis.Results A total of 6355 publications were included,with an average citation frequency of 7 times.The year 2021 witnessed the most publications (1406).The analysis with VOSviewer showed that the research on sudden death related to hypertrophic cardiomyopathy,especially the predictive value of late gadolinium-enhanced cardiac MRI in sudden death,was a hot topic.In addition,gene detection and the new drug mavacamten became hot research topics.The United States was the country with the largest number of publications and the highest citation frequency in this field.Chinese scholars produced the second largest number of publications,which,however,included few high-quality research results.Conclusions Risk stratification and prevention of sudden death is still an important and hot research content in the field of hypertrophic cardiomyopathy.Chinese scholars should carry out multi-center cooperation in the future to improve the research results.

Superconductivity at 40 K in Lithiation-Processed [(Fe,Al)(OH)2][FeSe]1.2 with a Layered Structure.

Exploration of new superconductors has always been one of the research directions in condensed matter physics. We report here a new layered heterostructure of [(Fe,Al)(OH)2][FeSe]1.2, which is synthesized by the hydrothermal ion-exchange technique. The structure is suggested by a combination of X-ray powder diffraction and the electron diffraction (ED). [(Fe,Al)(OH)2][FeSe]1.2 is composed of the alternating stacking of a tetragonal FeSe layer and a hexagonal (Fe,Al)(OH)2 layer. In [(Fe,Al)(OH)2][FeSe]1.2, there exists a mismatch between the FeSe sublayer and the (Fe,Al)(OH)2 sublayer, and the lattice of the layered heterostructure is quasi-commensurate. The as-synthesized [(Fe,Al)(OH)2][FeSe]1.2 is nonsuperconducting due to the Fe vacancies in the FeSe layer. The superconductivity with a Tc of 40 K can be achieved after a lithiation process, which is due to the elimination of the Fe vacancies in the FeSe layer. The Tc is nearly the same as that of (Li,Fe)OHFeSe although the structure of [(Fe,Al)(OH)2][FeSe]1.2 is quite different from that of (Li,Fe)OHFeSe. The new layered heterostructure of [(Fe,Al)(OH)2][FeSe]1.2 contains an iron selenium tetragonal lattice interleaved with a hexagonal metal hydroxide lattice. These results indicate that the superconductivity is very robust for FeSe-based superconductors. It opens a path for exploring superconductivity in iron-base superconductors.

Myocardial bridging of the left anterior descending coronary artery as a risk factor for atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy: a matched case-control study.

BACKGROUND: Myocardial bridging (MB) is associated with various forms of arrhythmia. However, whether MB is a risk factor for atrial fibrillation (AF) in patients with hypertrophic obstructive cardiomyopathy (HOCM) remains unknown. This study aimed to identify the relationship between myocardial bridging of the left anterior descending coronary artery (MB-LAD) and AF in patients with HOCM. METHODS: We reviewed the medical records of 1925 patients diagnosed with HOCM at Fuwai Hospital from January 2012 to March 2019. Patients with coronary artery disease, a history of heart surgery, and those who had not been subjected to angiography were excluded. Finally, 105 patients with AF were included in this study. The control group was matched in a ratio of 3:1 based on age and gender. RESULTS: Forty-three patients were diagnosed with MB-LAD in this study. The presence of MB was significantly higher in patients with AF than in those without AF (19.0% vs. 7.3%; p = 0.001), although MB compression and MB length did not differ between the two groups. In conditional multivariate logistic analysis, MB (odds ratio [OR] 2.33; 95% confidence interval [CI] 1.08-5.01; p = 0.03), pulmonary arterial hypertension (OR 2.63; 95% CI 1.26-5.47; p = 0.01), hyperlipidemia (OR 1.83; 95% CI 1.12-3.00; p = 0.016), left atrial diameter (OR 1.09; 95% CI 1.05-1.13; p < 0.001), and interventricular septal thickness (OR 1.06; 95% CI 1.003-1.12; p = 0.037) were independent risk factors for AF in patients with HOCM. CONCLUSIONS: The presence of MB is an independent risk factor for AF in patients with HOCM. The potential mechanistic link between MB and the development of AF warrants further investigation.

Midterm results of different treatment methods for myocardial bridging in patients after septal myectomy.

BACKGROUND: Myocardial bridging (MB) is commonly treated in patients with hypertrophic cardiomyopathy. However, whether and how MB should be treated in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent septal myectomy remain unclear. METHODS: A total of 823 adults with HOCM who underwent septal myectomy at the Fuwai Hospital from 2011 to 2017 were retrospectively studied. RESULTS: Overall, 31 events occurred: 24 patients died and 7 had nonfatal myocardial infarction (MI). The 3-year cumulative event-free survival of all-cause death (97.9% vs. 100% vs. 100% vs. 98.4%, p = .89) and cardiovascular death (98.3% vs. 100% vs. 100% vs. 98.4%, p = .63) were similar among the four groups (non-MB, coronary artery bypass grafting [CABG], unroofing, untreated, respectively). However, the 3-year cumulative event-free survival of nonfatal MI (100% vs. 97.5% vs. 98.0% vs. 89.9%, p < .001) and combined endpoints (97.9% vs. 97.5% vs. 98.0% vs. 88.4%, p = .02) were significantly lowest in untreated MB (non-MB, CABG, unroofing, untreated, respectively). Cox regression analysis indicated that untreated MB was a significant independent predictor of combined endpoints (hazard ratio: 4.06, 95% confidence interval: 1.60-10.32, p < .001). Moreover, 49 patients underwent coronary artery computed tomography 1 year after surgery. The patency rate of the saphenous vein graft was significantly higher than that of the left internal mammary artery (13.3% vs. 84.2%, p < .001). No MB was detected in the unroofing group. CONCLUSIONS: Surgical MB treatment could be beneficial and performed safely during septal myectomy. Myocardial unroofing is the recommended treatment for MB, and unroofing when technically possible may be preferable for long-term outcomes.

Impact of type 2 diabetes mellitus on mid-term mortality for hypertrophic cardiomyopathy patients who underwent septal myectomy.

BACKGROUND: Type 2 diabetes mellitus is common in cardiovascular disease. It is associated with adverse clinical outcomes for patients who had undergone coronary artery bypass and valve operations. The aim of this study was to evaluate the impact of type 2 diabetes mellitus on the midterm outcomes of patients with hypertrophic cardiomyopathy who underwent septal myectomy. METHODS: We retrospectively analyzed the data of 67 hypertrophic cardiomyopathy patients with type 2 diabetes mellitus who underwent septal myectomy from two medical centers in China from 2011 to 2018. A propensity score-matched cohort of 134 patients without type 2 diabetes mellitus was also analyzed. RESULTS: During a median follow-up of 28.0 (interquartile range: 13.0-3.0) months, 9 patients died. The cause of death of all of these patients was cardiovascular, particularly sudden cardiac death in 3 patients. Patients with type 2 diabetes mellitus had a higher rate of sudden cardiac death (4.5% vs. 0.0%, p = 0.04). The Kaplan-Meier survival analysis revealed that the rates of predicted 3-year survival free from cardiovascular death (98.1% vs. 95.1%, p = 0.14) were similar between the two groups. However, the rates of predicted 3-year survival free from sudden cardiac death (100% vs. 96.7%, p = 0.01) were significantly higher in hypertrophic cardiomyopathy patients without type 2 diabetes mellitus than in those with type 2 diabetes mellitus. Furthermore, after adjustment for age and sex, only N-terminal pro-brain natriuretic peptide (hazards ratio: 1.002, 95% confidence interval: 1.000-1.005, p = 0.02) and glomerular filtration rate ≤ 80 ml/min (hazards ratio: 3.23, 95% confidence interval: 1.34-7.24, p = 0.047) were independent risk factors for hypertrophic cardiomyopathy patients with type 2 diabetes mellitus. CONCLUSIONS: Hypertrophic cardiomyopathy patients with and without type 2 diabetes mellitus have similar 3-year cardiovascular mortality after septal myectomy. However, type 2 diabetes mellitus is associated with higher sudden cardiac death rate in these patients. In addition, N-terminal pro-brain natriuretic peptide and glomerular filtration rate ≤ 80 ml/min were independent risk factors among hypertrophic cardiomyopathy patients with type 2 diabetes mellitus.

Simple and sensitive method for the analysis of 14 antituberculosis drugs using liquid chromatography/tandem mass spectrometry in human plasma.

Monitoring plasma concentration and adjusting doses of antituberculosis (TB) drugs are beneficial for improving responses to drug treatment and avoiding adverse drug reactions. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to measure the plasma concentrations of 14 anti-TB drugs: ethambutol, isoniazid, pyrazinamide, levofloxacin, gatifloxacin, moxifloxacin, prothionamide, linezolid, rifampin, rifapentine, rifabutin, cycloserine, p-aminosalicylic acid, and clofazimine. METHODS: Human plasma was precipitated by acetonitrile and was subsequently separated by an AQ-C18 column with a gradient elution. Drug concentrations were determined using multiple reaction monitoring in positive ion electrospray ionization mode. According to pharmacokinetic data of patients, the peak concentration ranges and the timing of blood collection were determined. RESULTS: Intra- and interday precision was < 14.8%. Linearity, accuracy, extraction recovery, and matrix effect were acceptable for each drug. The stability of the method satisfied different storage conditions. CONCLUSIONS: The method allowed the sensitive and reproducible determination of 14 frequently used anti-TB drugs which has already been of benefit for some TB patients.

Effect of Septal Myectomy on Obstructive Sleep Apnoea Syndrome in Patients With Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND: The prevalence of obstructive sleep apnoea (OSA) is high in patients with hypertrophic cardiomyopathy. The effect of septal myectomy on OSA is not clear. This study aimed to examine the association between hypertrophic obstructive cardiomyopathy and OSA before and after septal myectomy. METHOD: We included 85 consecutive patents with a confirmed diagnosis of hypertrophic obstructive cardiomyopathy who underwent septal myectomy. Polysomnography was performed in all patients before and 3 months after the surgery. RESULTS: Of the 85 patients, 49 (58%) were diagnosed with OSA. Patients with OSA were significantly older than those without OSA. The incidence of atrial fibrillation significantly increased during the perioperative period in patients with OSA (p = 0.03). The severity of OSA significantly increased 3 months after surgery, as determined by the apnoea-hypopnoea index (AHI; p < 0.001), obstructive apnoea index (p = 0.024), and hypopnoea index (p = 0.003), whereas central apnoea index was decreased (p = 0.008). In the multivariate linear regression analysis, mean oxygen desaturation and time% with SpO2 <90% during sleep before surgery were significantly associated with increased AHI, independently of body mass index and sex (p = 0.026 and p = 0.007, respectively; adjusted R2 = 0.365). CONCLUSIONS: The severity of OSA significantly increased 3 months after septal myectomy as determined by AHI, obstructive apnoea index, and hypopnoea index. Mean oxygen saturation and time% with SpO2 <90% during sleep before surgery were independently associated with the increase of AHI. However, the specific mechanism of such deterioration of OSA after septal myectomy needs to be determined in detail.

Mid-term outcomes of simultaneous coronary artery bypass graft surgery and septal myectomy in patients with hypertrophic obstructive cardiomyopathy: A case-controlled study.

BACKGROUND: The mid-term outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing coronary artery bypass graft (CABG) is unclear. MATERIALS AND METHODS: We studied 44 patients with HOCM and coronary artery disease (CAD) who underwent septal myectomy and CABG) between 2011 and 2017. The control group was matched in a ratio of 4:1 based on age, sex, body mass index, hypertension, and chest pain. RESULTS: Compared to patients without CAD, patients with CAD had a higher long-term cardiovascular mortality rate (0.6% vs 6.8%, P = 0.03; hazard ratio [HR] = 8.16, 95% confidence interval [CI]: 1.27-74.48, P = 0.03). In addition, 10 out of 176 (5.7%) patients without CAD and nine out of 44 (20.5%) patients with CAD achieved the secondary endpoints (progressive heart failure, unexplained syncope, stroke, atrial fibrillation, and myocardial infarction) (HR = 2.89, 95%CI: 1.03-8.12, P = 0.04). The 5-year survival rate and cardiovascular event-free survival rate were significantly higher in patients without CAD than in those with CAD (97.4% vs 93.9%, P = 0.03; 89.2% vs 80.1%; P = 0.04). In the multivariate analysis, presence of CAD, New York Heart Association class, and left atrial diameter were predictors of combined cardiovascular events when adjusted for age and male sex. CONCLUSIONS: The cardiovascular death and cardiovascular events are significantly increased in patients with HOCM and CAD who underwent CABG at the time of septal myectomy.

Predictors of long-term outcome after septal myectomy in symptomatic hypertrophic obstructive cardiomyopathy patients with previous alcohol septal ablation and residual obstruction.

BACKGROUND AND AIM: Recently alcohol septal ablation (ASA) has emerged as an alternative treatment for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) and a subgroup of HOCM patients with previous ASA may need myectomy. However, subsequent outcome and mechanism of residual obstruction has not been determined. This study aims to determine outcome after myectomy and mechanism of residual obstruction in HOCM patients with previous ASA. METHODS: From February 2009 to June 2017, 38 HOCM patients with previous ASA underwent surgical septal myectomy at our institution. Seventy-six patients who underwent surgical septal myectomy initially were included as the comparison group through one-to-two propensity score matching method. RESULTS: Fourteen available cardiac magnetic resonance images revealed inferior location and small area of infarcted myocardium induced by ASA in 12 patients and outside targeted location in two patients. During follow-up (median, 2.4; maximum, 7.8 years), event-free survival at 7 years was 83.2% in the previous ASA group and 94.6% in the comparison group, respectively (P = 0.0378). Multivariable analysis indicated previous ASA (hazard ratio, 4.28; 95% confidence intervals [CI], 1.20-15.26; P = 0.025) and postoperative left ventricular end-diastolic diameter (hazard ratio, 1.14; 95% CI, 1.05-1.23; P = 0.002) were independent predictors of adverse events. CONCLUSIONS: This study demonstrated that uncontrollable extent and location of infarcted myocardium induced by ASA may attribute to residual obstruction after previous ASA, and the long-term event-free survival after myectomy was inferior. It may provide special precaution to patient selection and the increased number of ASA practiced worldwide.

Time and age dependent decrease of NT-proBNP after septal myectomy in hypertrophic obstructive cardiomyopathy.

BACKGROUND: NT-proBNP level is a predictive factor in hypertrophic cardiomyopathy patients, in which left ventricular outflow tract obstruction contributes to an increased NT-proBNP level. However, studies regarding the influence of septal myectomy on NT-proBNP level in hypertrophic obstructive cardiomyopathy are lacking. METHODS: One hundred and eighty-two patients who underwent septal myectomy in Fuwai Hospital from May 2011 to March 2016 and were included in the present study. Preoperative and follow-up NT-proBNP was retrospectively collected. Correlation analysis was performed to determine the factors affecting preoperative NT-proBNP and postoperative decrease. RESULTS: The cohort had a median age of 46.2 [IQR: 36.5-53.1] years, and 106 (58.2%) patients were male. NT-proBNP decreased to 816.5 [IQR: 400.3-1661.8] pg/mL from preoperative 1732.4 [IQR: 819-3296.5] pg/mL (p<0.001). Baseline NT-proBNP was correlated with gender (p<0.001), maximum septal thickness (p<0.001), and resting pressure gradient (p=0.006). The extent of NT-proBNP decrease was positively correlated with age (p<0.001), baseline NT-proBNP (p<0.001), follow-up time (p=0.020), and enlargement of the ascending aorta (p=0.019). NT-proBNP exhibited a persistent decrease after myectomy. CONCLUSIONS: Myectomy significantly reduced NT-proBNP level in hypertrophic obstructive cardiomyopathy patients, in which a time-dependent manner of decrease indicated myocardial remodeling of the heart after myectomy.

Analysis and evaluation of patient-specific three-dimensional printing in complex septal myectomy.

OBJECTIVES: This study aimed to assess the effectiveness of three-dimensional printing (3DP) in patients with complex hypertrophic cardiomyopathy requiring combined transaortic and transapical septal myectomy. METHODS: We created 3DP models for 7 patients undergoing this surgery approach between June and October 2022 using silicone-like resin and conducted mock operations. The models were compared with echocardiography to identify abnormal muscle bundles and heart structures. These patients were then compared with a 1:2 matched group without 3DP, considering age, sex and additional operations. RESULTS: The models mostly presenting with midventricular obstruction showed high consistency with original computed tomography data (r = 0.978, P < 0.001). 3DP identified more abnormal muscle bundles than echocardiography, primarily between the interventricular septum and apex. Excised specimens in mock operations mirrored those in actual myectomies. While cardiopulmonary bypass time was not significantly different, a near-20-min decrease was observed in the 3DP group (135.5 ± 31.1 vs 154.4 ± 36.6 min, P = 0.054). CONCLUSIONS: While no significant differences in surgical outcomes were observed, 3DP appeared to enhance the visualization and understanding of spatial structures (average Likert scale score 4.0), potentially contributing to surgical proficiency (overall rating score 3.9). The use of 3DP may offer additional value in the preparation and execution of operations for complex hypertrophic cardiomyopathy cases.

Adaptive autonomous emergency braking model based on weather conditions.

OBJECTIVE: Vehicle active safety systems can improve vehicle security by avoiding collisions. An autonomous emergency braking (AEB) system's safety distance calculation is usually based on normal weather conditions. The AEB system's early warning capabilities decrease during adverse weather conditions. METHODS: A multilayer perceptron (MLP) model is used to obtain data from accident and weather data sets. The MLP model is trained and the severity of accidents is predicted. The severity is used as a parameter to build an adaptive AEB system algorithm that considers adverse weather conditions. RESULTS: The adaptive AEB system algorithm increases safety and reliability under adverse weather conditions. Prescan and a driver-in-the-loop system are used to test the adaptive AEB model. Both tests show that the adaptive AEB model has better performance under adverse weather than the traditional AEB model. CONCLUSIONS: The experimental results demonstrate that the adaptive AEB system can increase the safety distance in rainy weather and avoid collisions under hazy conditions.

Atrial high-rate episode burden and stroke risks for patients with device-detected subclinical atrial fibrillation: A systematic review and meta-analysis.

BACKGROUND: Atrial high-rate episode (AHRE) and stroke are related; however, the magnitude of the correlations between different AHRE burdens and stroke remains unknown. We analysed studies that evaluated this relationship. METHODS: We searched for observational controlled studies that reported the associations of different AHRE burdens with stroke in populations with cardiac implantable electronic devices (CIEDs). The primary endpoint was stroke or thrombosis during follow-up. We performed subgroup analyses according to the classification criteria and research design of the included studies. RESULTS: Of the 5985 studies identified, 9 met the eligibility criteria and included 42,958 patients. Patients with low and high AHRE burdens had a 1.2-fold risk of stroke (no heterogeneity) and a 2.52-fold risk of stroke (moderate heterogeneity), respectively. After excluding studies analysing the atrial fibrillation history, no significant difference in progressive stroke risk was observed for patients with a low AHRE burden (without significant heterogeneity). An increased likelihood of stroke was observed for patients with a high AHRE burden (decreased heterogeneity). Four of the nine studies classified high and low AHRE burdens using the longest AHRE time. Five studies classified high and low AHRE burdens based on the median of the total AHRE time as the cutoff value. Low and high AHRE burdens were more closely related to stroke when classified by the total AHRE duration than when classified by the single longest AHRE duration. CONCLUSIONS: For populations with CIEDs without an atrial fibrillation history, a high AHRE burden was significantly associated with stroke.

Mitral annular calcification in obstructive hypertrophic cardiomyopathy: Incidence, risk factors, and prognostic value after myectomy.

BACKGROUND: Mitral annular calcification (MAC) is a risk factor for cardiac surgery, but there is limited study on the prognosis value and the impact for valve function of MAC based on computed tomography (CT) diagnosis after myectomy for hypertrophic obstructive cardiomyopathy (OHCM). METHODS: Consecutive OHCM patients underwent septal myectomy were compared according to the existence of MAC and its severity in preoperative CT scans. The survival data were evaluated and compared by Kaplan Meier analysis and log rank test. Cox regression analysis was used to evaluate the impact of MAC on endpoint events. RESULTS: From the entire cohort of 1035 patients, 10.8% had MAC. In multivariate regression, female (OR = 2.23), age (OR = 1.07), aortic annular calcification (OR = 2.52), aortic calcification (OR = 2.56), systolic anterior motion of the mitral valve (SAM) (OR = 0.42), mitral valve thickening (OR = 2.13), and tricuspid regurgitation (OR = 3.12) were independent predictors of MAC. All-cause mortality (3.57% vs. 1.08%, p = 0.031), major adverse cardiovascular and cerebrovascular events (MACCE) (23.32% vs. 13.65%, p = 0.014), recurrent MR > 2+ (8.04% vs. 2.49%, p = 0.001) and NYHA III-IV (11.61% vs. 5.53%, p = 0.012) were more frequent in OHCM patients with MAC after myectomy. MAC was discovered to be an independent predictor of postoperative recurrent MR > 2+ after other risk factors were taken into account (HR 2.47, 95% CI 1.08-5.67, p = 0.0329). Moderate-to-severe MAC was an independent risk factor (HR 2.03, 95% CI 1.09-3.75, p = 0.0244) for long-term major adverse cardiovascular and cerebrovascular events (MACCE). CONCLUSION: MAC was detected in one-tenth of OHCM patients in preoperative CT scanning and is mainly associated with aging and atherosclerosis. OHCM patients with MAC had a worse prognosis and more recurrent mitral valve regurgitation than those without MAC after septal myectomy.

High-Burden Premature Atrial Contractions Predict New-Onset Atrial Fibrillation After Surgical Septal Myectomy.

Although increased premature atrial contractions (PACs) reportedly predict atrial fibrillation (AF) in both general and specific (e.g., patients with stroke) populations, early postoperative AF (POAF) risk in patients with increased PAC burden who require cardiac surgery remains unclear. We examined the correlation between different preoperative PAC burdens and POAF in patients with obstructive hypertrophic cardiomyopathy (OHCM) who underwent surgical treatment. We analyzed 304 consecutively admitted patients with OHCM without previous AF who underwent isolated septal myectomy between January 2015 and December 2018. All patients underwent preoperative 24-hour Holter electrocardiogram monitoring. PACs were present in 259 patients (85.20%) and absent in 45 patients (14.80%). According to the cut-off PAC number of 100 beats/24 hours, there were 211 patients (69.41%) with low-burden PACs and 48 patients (15.79%) with high-burden PACs. AF after septal myectomy occurred in 73 patients, which consisted of 3/45 in the non-PAC group (6.67%), 47/211 in the low-PAC-burden group (22.27%), and 23/48 in the high PAC burden group (47.92%). POAF incidence was higher in both low- and high-burden patients than in patients without PAC (p <0.01). Multivariate logistic regression analyses demonstrated that high-burden PACs (p = 0.02) and age (p <0.01) but not low-burden PACs (p = 0.22) independently predicted POAF in patients with OHCM. The area under the receiver operating characteristic curve for preoperative PACs was 0.72 (95% confidence interval 0.66 to 0.79, p <0.01, sensitivity: 68.49%, specificity: 69.26%). In conclusion, POAF incidence was significantly higher in patients with preoperative high-burden PACs and can predict POAF in patients with OHCM.

Hypertrophic cardiomyopathy in children.

Hypertrophic cardiomyopathy (HCM) characterized by asymmetric ventricular septal hypertrophy, is the commonest cause of sudden cardiac death (SCD) in the young. The underlying etiology of HCM in the childhood and adolescent patients is diverse. Moreover, the prognosis of pediatric HCM depends on the age of presentation and etiology. Despite the complexity of children with obstructive HCM, surgical treatment results in a favorable outcome for carefully selected patients in experienced tertiary referral center in contemporary era. Implantable cardioverter-defibrillator (ICD) remains the most effective and reliable treatment to prevent SCD. New pediatric SCD risk prediction model, which has good discrimination and calibration and can distinguish patients who are most benefit from an ICD implantation, is expected to be further refined in the future.

Left ventricular basal muscle bundle in hypertrophic cardiomyopathy: insights into the mechanism of left ventricular outflow tract obstruction.

AIMS: Many factors cause left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM). Previous studies reported that left ventricular basal muscle bundle (BMB) may be associated with LVOTO. We aimed to evaluate the role of BMB in LVOTO by echocardiography. METHODS AND RESULTS: Two hundred fifty-six patients diagnosed with HCM were recruited. The morphologic characteristics of left ventricular outflow tract (LVOT) were analysed. BMB was detected in 178 (69.5%) patients by echocardiography. Patients were separated by a resting or provocative LVOT gradient ≥30 mmHg or not. Compared to patients without LVOTO, patients with LVOTO had a significantly thicker basal septum, elongated anterior mitral leaflet (AML), shorter distance between the AML-free margin and the septum or BMB (M-sept/bundle), larger angle between the plane of the mitral valvular orifice and the ascending aorta (MV-AO angle), and higher prevalence of BMB (P < 0.05). According to multivariate analysis, the independent predictors of LVOTO were the presence of BMB, a large basal septum thickness, a short M-sept/bundle, a large MV-AO angle, and a large AML [odds ratio (95% confidence interval): 5.207 (1.381-19.633), 1.386(1.141-1.683), 0.615(0.499-0.756), 1.113(1.054-1.176), and 1.343(1.076-1.677), respectively, P < 0.05]. Of the 256 included patients, 139 underwent surgical myectomy. The transthoracic echocardiography, compared with surgical specimen, showed: sensitivity 98.3%, specificity 82.3%, positive predictive value 97.6%, negative predictive value 87.5%, and accuracy 96.4% to detect BMB. CONCLUSIONS: BMB is common in HCM. BMB is a risk factor for LVOTO.