21 research outputs found

    The integrated angular bispectrum

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    We study the position-dependent power spectrum and the integrated bispectrum statistic for 2D cosmological fields on the sphere (integrated angular bispectrum). First, we derive a useful, mm-independent, formula for the full-sky integrated angular bispectrum, based on the construction of azimuthally symmetric patches. We then implement a pipeline for integrated angular bispectrum estimation, including a mean-field correction to account for spurious isotropy-breaking effects in realistic conditions (e.g., inhomogenous noise, sky masking). Finally, we show examples of applications of this estimator to CMB analysis, both using simulations and actual Planck data. Such examples include fNLf_\mathrm{NL} estimation, analyses of non-Gaussianity from secondary anisotropies (ISW-lensing and ISW-tSZ-tSZ bispectra) and studies of non-Gaussian signatures from foreground contamination.Comment: 38 pages, 14 figure

    Evidence of tricuspid valve remodeling in patients with severe mitral regurgitation independently of degree of functional tricuspid regurgitation: a two- and three-dimensional echocardiographic study

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    The study aim was to evaluate whether, in patients with severe mitral regurgitation (MR), tricuspid valve remodeling was independent of the degree of functional tricuspid regurgitation (FTR) present. Whether any differences in the analysis remodeling, as assessed by two-dimensional (2D) and three-dimensional (3D) echocardiography, can be demonstrated was also addressed

    Echocardiographic classification of chronic ischemic mitral regurgitation caused by restricted motion according to tethering pattern

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    Although the mechanism of ischemic mitral regurgitation (MR) is understood, the echocardiographic picture of ischemic MR is not homogeneous. Ninety-two consecutive patients with chronic ischemic MR due to restricted motion were divided into two groups according to tethering pattern: the asymmetric group with predominant posterior tethering of both leaflets (54 patients) and the symmetric one with predominant apical tethering of both leaflets (38 patients). The mitral deformation indexes, LV global (volume, function and sphericity) and local (papillary muscle displacements and regional wall motion score index) remodeling were evaluated. All indexes of global LV remodeling were significantly higher in the symmetric than asymmetric group (all p<0.0001), such as the posterior and lateral displacement of the anterior papillary muscle (both p<0.04), the papillary muscle separation and the anterior papillary muscle wall motion index (both p<0.0001). The origin as well as the direction of the jet was central in all patients of the symmetric group. In the asymmetric one the origin was central in 78% of the cases and arising from the medial commissure in 22% whereas the jet direction was posterior and central in 83% and 17% of patients, respectively. Therefore, it is possible to distinguish at least two subgroups of patients with ischemic MR due to restricted motion on the basis of tethering pattern, different degree of local and global LV remodeling and characteristics of the regurgitant jet

    Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target

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    Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF poses patients at increased risk of thromboembolism, in particular ischemic stroke. The CHADS2 and CHA2DS2-VASc scores are useful in the assessment of thromboembolic risk in nonvalvular AF and are utilized in decision-making about treatment with oral anticoagulation (OAC). However, OAC is underutilized due to poor patient compliance and contraindications, especially major bleedings. The Virchow triad synthesizes the pathogenesis of thrombogenesis in AF: endocardial dysfunction, abnormal blood stasis, and altered hemostasis. This is especially prominent in the left atrial appendage (LAA), where the low flow reaches its minimum. The LAA is the remnant of the embryonic left atrium, with a complex and variable morphology predisposing to stasis, especially during AF. In patients with nonvalvular AF, 90% of thrombi are located in the LAA. So, left atrial appendage occlusion could be an interesting and effective procedure in thromboembolism prevention in AF. After exclusion of LAA as an embolic source, the remaining risk of thromboembolism does not longer justify the use of oral anticoagulants. Various surgical and catheter-based methods have been developed to exclude the LAA. This paper reviews the physiological and pathophysiological role of the LAA and catheter-based methods of LAA exclusion

    Impact and evolution of right ventricular dysfunction after successful MitraClip implantation in patients with functional mitral regurgitation

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    Right ventricular dysfunction (RVdysf) is a predictor of poor outcome in patients with heart failure and valvular disease. The aim of this study was to evaluate the evolution and the impact of RVdysf in patients with moderate–severe functional mitral regurgitation (FMR) successfully treated with MitraClip. From October 2008 to July 2014, 60 consecutive high surgical risk FMR patients were evaluated and stratified into two groups: RVdysf group (TAPSE < 16 mm and/or S′TDI < 10 cm/s, 21 patients) and No-RVdysf group (38 patients). The overall mean age of patients was 73 ± 8 (83% male). Ischemic FMR etiology was present in 67%. Mean LVEF was 30 ± 10%. Overall mean time follow-up was 565 ± 310 days. The only significant difference between the two groups was a greater prevalence of stroke, ICD and use of aldosterone antagonist in RVdysf group. Acute procedural success was achieved in 90% of patients. At 6-month echo-matched analysis significant RV function improvement was observed in patients with baseline RVdysf (TAPSE 15 ± 3.0 vs. 19 ± 4.5, p = 0.007, S′TDI 7 ± 1.2 vs. 11 ± 2.8, p < 0.0001, baseline vs. 6-month, respectively). The mean improvement in the 6-min walking test was significant in both groups (120 and 143 m, RVdysf and No-RVdysf groups, respectively). At Kaplan–Meier analysis, the presence of RVdysf did not affect the outcome in terms of freedom from composite efficacy endpoint. This study shows that successful MitraClip implantation in patients with FMR and concomitant right ventricular dysfunction yields significant improvement of RV function at mid-term follow-up. Further data on larger population will be required to confirm our observations
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