123 research outputs found

    Incremental Evaluation of Rules and its Relationship to Parallelism

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    Rule interpreters usually start with an initial database and perform the inference procedure in cycles, ending with a final database. In a real time environment it is possible to receive updates to the initial database after the inference procedure has started or even after it has ended. We present an algorithm for incremental maintenance of the deductive database in the presence of such updates. Interestingly, the same algorithm is useful for parallel and distributed rule processing in the following sense. \\'hen the processors evaluating a program operate asynchronously. then they may have different views of the database. The incremental maintenance procedure we present can be used to synchronize these views

    Model-Based Analysis of Flow-Mediated Dilation and Intima-Media Thickness

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    We present an end-to-end system for the automatic measurement of flow-mediated dilation (FMD) and intima-media thickness (IMT) for the assessment of the arterial function. The video sequences are acquired from a B-mode echographic scanner. A spline model (deformable template) is fitted to the data to detect the artery boundaries and track them all along the video sequence. The a priori knowledge about the image features and its content is exploited. Preprocessing is performed to improve both the visual quality of video frames for visual inspection and the performance of the segmentation algorithm without affecting the accuracy of the measurements. The system allows real-time processing as well as a high level of interactivity with the user. This is obtained by a graphical user interface (GUI) enabling the cardiologist to supervise the whole process and to eventually reset the contour extraction at any point in time. The system was validated and the accuracy, reproducibility, and repeatability of the measurements were assessed with extensive in vivo experiments. Jointly with the user friendliness, low cost, and robustness, this makes the system suitable for both research and daily clinical use

    Does Heterogeneity Exist in Treatment Associations With Renin–Angiotensin–System Inhibitors or Beta-blockers According to Phenotype Clusters in Heart Failure with Preserved Ejection Fraction?

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    BACKGROUND: We explored the association between use of renin–angiotensin system inhibitors and beta-blockers, with mortality/morbidity in 5 previously identified clusters of patients with heart failure with preserved ejection fraction (HFpEF). METHODS AND RESULTS: We analyzed 20,980 patients with HFpEF from the Swedish HF registry, phenotyped into young–low comorbidity burden (12%), atrial fibrillation–hypertensive (32%), older–atrial fibrillation (24%), obese–diabetic (15%), and a cardiorenal cluster (17%). In Cox proportional hazard models with inverse probability weighting, there was no heterogeneity in the association between renin–angiotensin system inhibitor use and cluster membership for any of the outcomes: cardiovascular (CV) mortality, all-cause mortality, HF hospitalisation, CV hospitalisation, or non-CV hospitalisation. In contrast, we found a statistical interaction between beta-blocker use and cluster membership for all-cause mortality (P = .03) and non-CV hospitalisation (P = .001). In the young–low comorbidity burden and atrial fibrillation–hypertensive cluster, beta-blocker use was associated with statistically significant lower all-cause mortality and non-CV hospitalisation and in the obese–diabetic cluster beta-blocker use was only associated with a statistically significant lower non-CV hospitalisation. The interaction between beta-blocker use and cluster membership for all-cause mortality could potentially be driven by patients with improved EF. However, patient numbers were diminished when excluding those with improved EF and the direction of the associations remained similar. CONCLUSIONS: In patients with HFpEF, the association with all-cause mortality and non-CV hospitalisation was heterogeneous across clusters for beta-blockers. It remains to be elucidated how heterogeneity in HFpEF could influence personalized medicine and future clinical trial design

    Right ventricular dysfunction in right coronary artery infarction: A primary PCI registry analysis

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    Right ventricular involvement in inferior myocardial infarction (MI) was historically associated with a poor prognosis. However, few studies addressed the impact of right ventricular (RV) dysfunction in the primary percutaneous intervention (pPCI) era. Our aim was to assess the prognostic significance of RV dysfunction in right coronary artery (RCA) related MI treated with pPCI. Methods: A total of 298 patients with a RCA related MI undergone pPCI between January 2011 and June 2015 were included. RV dysfunction was defined by a RV-FAC <35% at echocardiographic examination and further divided into mild (RV-FAC between 35 and 25%) and moderate-severe (RV-FAC <25%). RV function before discharge was reassessed in 95% of the study cohort. The primary endpoint was overall mortality. Median follow-up was 29 months. Results: In RCA related MI, moderate-severe (HR 5.882, p = 0.002, 95% CI 1.882-18.385) but not mild RV dysfunction independently predicted lower survival at follow-up along with age (HR 1.104, p <0.001, CI 1.045-1.167). Importantly, patients recovering RV function at discharge showed a lower mortality (p = 0.001) vs patients with persistent moderate-severe RV dysfunction) that approached the risk of patients without RV dysfunction at presentation. Conclusion: In RCA related MI treated with pPCI, RV dysfunction was one of the strongest independent predictor of lower overall survival. However, patients with only transient RV dysfunction showed a better prognosis compared to patients who had persistent RV dysfunction. The focus on intensive support management of the RV in the first hours after pPCI may be important to overcome the acute phase and to promote RV recovery

    Impact of patient delay in a modern real world STEMI network

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    Background: The impact of patient delay on left ventricular ejection fraction (LVEF), when system delay has performance that meets the current recommended guidelines, is poorly investigated. Methods: We evaluated a cohort of STEMI patients treated with primary percutaneous coronary intervention (pPCI) and with an ECG STEMI diagnosis to wire crossing time (ETW) 64120 min. Independent predictors of pre-discharge decreased LVEF ( 6445%) were analyzed. Results: 490 STEMI patients with both ETW time 64120 min and available pre-discharge LVEF were evaluated. Mean age was 64.2 \ub1 12 years, 76.2% were male, 19.5% were diabetics, 42.7% had and anterior myocardial infarction (MI), and 9.8% were in Killip class III\u2013IV. Median time of patient's response to initial symptoms (patient delay) was 58,5 (IQR 30;157) minutes and median ETW time was 78 (IQR 62\u201395) minutes. 115 patients (23.4%) had pre-discharge LVEF 6445%. At multivariable analysis independent predictors of decreased LVEF ( 6445%) were anterior MI (OR 4,659, 95% CI 2,618-8,289, p < 0,001), Killip class (OR 1,449, 95% CI 1,090-1,928, p = 0,011) and patients delay above the median (OR 2,030, 95% CI 1,151\u20133.578, p = 0,014). These independent predictors were confirmed in patients with ETW time 6490 min. Conclusions: When system delay meets the recommended criteria for pPCI, patient delay becomes an independent predictor of pre-discharge LVEF. These findings provide further insights into the potential optimization of STEMI management and identify a target that needs to be improved, considering that still a significant proportion of patients continue to delay seeking medical care

    A Scalable Malware Classification based on Integrated Static and Dynamic Features

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    This paper presents a malware classification approach which aims to improve precision and support scalability. To this end, a hybrid approach combining both static and dynamic features is adopted. The hybrid approach has the advantage of being a complete and robust solution to evasion techniques used by malware writers. The proposed methodology allowed achieving a very promising accuracy of 99.41% in classifying malware into families while considerably reducing the feature space compared to competing approaches in the literature

    Accuracy of right atrial pressure estimation using a multi-parameter approach derived from inferior vena cava semi-automated edge-tracking echocardiography: a pilot study in patients with cardiovascular disorders

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    The echocardiographic estimation of right atrial pressure (RAP) is based on the size and inspiratory collapse of the inferior vena cava (IVC). However, this method has proven to have limits of reliability. The aim of this study is to assess feasibility and accuracy of a new semi-automated approach to estimate RAP. Standard acquired echocardiographic images were processed with a semi-automated technique. Indexes related to the collapsibility of the vessel during inspiration (Caval Index, CI) and new indexes of pulsatility, obtained considering only the stimulation due to either respiration (Respiratory Caval Index, RCI) or heartbeats (Cardiac Caval Index, CCI) were derived. Binary Tree Models (BTM) were then developed to estimate either 3 or 5 RAP classes (BTM3 and BTM5) using indexes estimated by the semi-automated technique. These BTMs were compared with two standard estimation (SE) echocardiographic methods, indicated as A and B, distinguishing among 3 and 5 RAP classes, respectively. Direct RAP measurements obtained during a right heart catheterization (RHC) were used as reference. 62 consecutive \u2018all-comers\u2019 patients that had a RHC were enrolled; 13 patients were excluded for technical reasons. Therefore 49 patients were included in this study (mean age 62.2\ua0\ub1\ua015.2\ua0years, 75.5% pulmonary hypertension, 34.7% severe left ventricular dysfunction and 51% right ventricular dysfunction). The SE methods showed poor accuracy for RAP estimation (method A: misclassification error, ME\ua0=\ua051%, R2\ua0=\ua00.22; method B: ME\ua0=\ua069%, R2\ua0=\ua00.26). Instead, the new semi-automated methods BTM3 and BTM5 have higher accuracy (ME\ua0=\ua014%, R2\ua0=\ua00.47 and ME\ua0=\ua022%, R2\ua0=\ua00.61, respectively). In conclusion, a multi-parametric approach using IVC indexes extracted by the semi-automated approach is a promising tool for a more accurate estimation of RAP

    Regional Variation in RBM20 Causes a Highly Penetrant Arrhythmogenic Cardiomyopathy

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    Background Variants in the cardiomyocyte-specific RNA splicing factor RBM20 have been linked to familial cardiomyopathy, but the causative genetic architecture and clinical consequences of this disease are incompletely defined. Methods and Results To define the genetic architecture of RBM20 cardiomyopathy, we first established a database of RBM20 variants associated with cardiomyopathy and compared these to variants observed in the general population with respect to their location in the RBM20 coding transcript. We identified 2 regions significantly enriched for cardiomyopathy-associated variants in exons 9 and 11. We then assembled a registry of 74 patients with RBM20 variants from 8 institutions across the world (44 index cases and 30 from cascade testing). This RBM20 patient registry revealed highly prevalent family history of sudden cardiac death (51%) and cardiomyopathy (72%) among index cases and a high prevalence of composite arrhythmias (including atrial fibrillation, nonsustained ventricular tachycardia, implantable cardiac defibrillator discharge, and sudden cardiac arrest, 43%). Patients harboring variants in cardiomyopathy-enriched regions identified by our variant database analysis were enriched for these findings. Further, these characteristics were more prevalent in the RBM20 registry than in large cohorts of patients with dilated cardiomyopathy and TTNtv cardiomyopathy and not significantly different from a cohort of patients with LMNA-associated cardiomyopathy. Conclusions Our data establish RBM20 cardiomyopathy as a highly penetrant and arrhythmogenic cardiomyopathy. These findings underline the importance of arrhythmia surveillance and family screening in this disease and represent the first step in defining the genetic architecture of RBM20 disease causality on a population level
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