507 research outputs found
Contact force sensing in ablation of ventricular arrhythmias using a 56-hole open-irrigation catheter: a propensity-matched analysis.
PURPOSE: The effect of adding contact force (CF) sensing to 56-hole tip irrigation in ventricular arrhythmia (VA) ablation has not been previously studied. We aimed to compare outcomes with and without CF sensing in VA ablation using a 56-hole radiofrequency (RF) catheter. METHODS: A total of 164 patients who underwent first-time VA ablation using Thermocool SmartTouch Surround Flow (TC-STSF) catheter (Biosense-Webster, Diamond Bar, CA, USA) were propensity-matched in a 1:1 fashion to 164 patients who had first-time ablation using Thermocool Surround Flow (TC-SF) catheter. Patients were matched for age, gender, cardiac aetiology, ejection fraction and approach. Acute success, complications and long-term follow-up were compared. RESULTS: There was no difference between procedures utilising either TC-SF or TC-STSF in acute success (TC-SF: 134/164 (82%), TC-STSF: 141/164 (86%), p = 0.3), complications (TC-SF: 11/164 (6.7%), TC-STSF: 11/164 (6.7%), p = 1.0) or VA-free survival (TC-SF: mean arrhythmia-free survival time = 5.9 years, 95% CI = 5.4-6.4, TC-STSF: mean = 3.2 years, 95% CI = 3-3.5, log-rank p = 0.74). Fluoroscopy time was longer in normal hearts with TC-SF (19 min, IQR: 14-30) than TC-STSF (14 min, IQR: 8-25; p = 0.04). CONCLUSION: Both TC-SF and TC-STSF catheters are safe and effective in treating VAs. The use of CF sensing catheters did not improve safety or acute and long-term outcomes, but reduced fluoroscopy time in normal heart VA
Crystal structures of self-assembled nanotubes from flexible macrocycles by weak interactions
8 páginas, 7 figuras, 2 tablas, 2 esquemas.Herein we report the crystal structures of tubular self-assemblies of flexible macrooligolides. The assembly is driven by the propensity of the macrocycles to create nearly flat structures displaying a void space within them and the cooperativity of weak directional interactions such as dipole–dipole interactions and CH***Ohydrogen bonds and non-directional interactions such as van der Waals contacts. The significance of the stereochemistry and the size of the cavity in the formation of the nanotubes are also studied.This research was supported by the Spanish MICINN-FEDER
(CTQ2008-03334/BQU, CTQ2008-06806-C02-01/BQU and
CTQ2008-06754-C04-01/PPQ), the MSC (RTICC RD06/0020/
1046) and the Canary Islands FUNCIS (PI 01/06).Peer reviewe
A Comparative Assessment of Machine-Learning Techniques for Forest Degradation Caused by Selective Logging in an Amazon Region Using Multitemporal X-Band SAR Images.
Abstract: The near-real-time detection of selective logging in tropical forests is essential to support actions for reducing CO2 emissions and for monitoring timber extraction from forest concessions in tropical regions. Current operating systems rely on optical data that are constrained by persistent cloud-cover conditions in tropical regions. Synthetic aperture radar data represent an alternative to this technical constraint. This study aimed to evaluate the performance of three machine learning algorithms applied to multitemporal pairs of COSMO-SkyMed images to detect timber exploitation in a forest concession located in the Jamari National Forest, Rondônia State, Brazilian Amazon. The studied algorithms included random forest (RF), AdaBoost (AB), and multilayer perceptron artificial neural network (MLP-ANN). The geographical coordinates (latitude and longitude) of logged trees and the LiDAR point clouds before and after selective logging were used as ground truths. The best results were obtained when the MLP-ANN was applied with 50 neurons in the hidden layer, using the ReLu activation function and SGD weight optimizer, presenting 88% accuracy both for the pair of images used for training (images acquired in June and October) of the network and in the generalization test, applied on a second dataset (images acquired in January and June). This study showed that X-band SAR images processed by applying machine learning techniques can be accurately used for detecting selective logging activities in the Brazilian Amazon
Sex-specific efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation: An individual patient data meta-analysis
BACKGROUND: Atrial fibrillation (AF) is a growing health burden, and pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) represents an attractive therapeutic option. Sex-specific differences in the epidemiology, pathophysiology, and clinical presentation of AF and PVI are recognized. OBJECTIVE: We aimed at comparing the efficacy, safety, and procedural characteristics of CB and RF in women and men undergoing a first PVI procedure. METHODS: We searched for randomized controlled trials and prospective observational studies comparing CB and RF ablation with at least 1 year of follow-up. After merging individual patient data from 18 data sets, we investigated the sex-specific (procedure failure defined as recurrence of atrial arrhythmia, reablation, and reinitiation of antiarrhythmic medication), safety (periprocedural complications), and procedural characteristics of CB vs RF using Kaplan-Meier and multilevel models. RESULTS: From the 18 studies, 4840 men and 1979 women were analyzed. An analysis stratified by sex correcting for several covariates showed a better efficacy of CB in men (hazard ratio for recurrence 0.88; 95% confidence interval 0.78-0.98, P = .02) but not in women (hazard ratio 0.98; 95% confidence interval 0.83-1.16; P = .82). For women and men, the energy source had no influence on the occurrence of at least 1 complication. For both sexes, the procedure time was significantly shorter with CB (-22.5 minutes for women and -27.1 minutes for men). CONCLUSION: CB is associated with less long-term failures in men. A better understanding of AF-causal sex-specific mechanisms and refinements in CB technologies could lead to higher success rates in women
Ordinal-Level Phylogenomics of the Arthropod Class Diplopoda (Millipedes) Based on an Analysis of 221 Nuclear Protein-Coding Loci Generated Using Next-Generation Sequence Analyses
Background
The ancient and diverse, yet understudied arthropod class Diplopoda, the millipedes, has a muddled taxonomic history. Despite having a cosmopolitan distribution and a number of unique and interesting characteristics, the group has received relatively little attention; interest in millipede systematics is low compared to taxa of comparable diversity. The existing classification of the group comprises 16 orders. Past attempts to reconstruct millipede phylogenies have suffered from a paucity of characters and included too few taxa to confidently resolve relationships and make formal nomenclatural changes. Herein, we reconstruct an ordinal-level phylogeny for the class Diplopoda using the largest character set ever assembled for the group.
Methods
Transcriptomic sequences were obtained from exemplar taxa representing much of the diversity of millipede orders using second-generation (i.e., next-generation or high-throughput) sequencing. These data were subject to rigorous orthology selection and phylogenetic dataset optimization and then used to reconstruct phylogenies employing Bayesian inference and maximum likelihood optimality criteria. Ancestral reconstructions of sperm transfer appendage development (gonopods), presence of lateral defense secretion pores (ozopores), and presence of spinnerets were considered. The timings of major millipede lineage divergence points were estimated.
Results
The resulting phylogeny differed from the existing classifications in a number of fundamental ways. Our phylogeny includes a grouping that has never been described (Juliformia+Merocheta+Stemmiulida), and the ancestral reconstructions suggest caution with respect to using spinnerets as a unifying characteristic for the Nematophora. Our results are shown to have significantly stronger support than previous hypotheses given our data. Our efforts represent the first step toward obtaining a well-supported and robust phylogeny of the Diplopoda that can be used to answer many questions concerning the evolution of this ancient and diverse animal group
Clinically relevant potential drug-drug interactions in intensive care patients:A large retrospective observational multicenter study
Purpose: Potential drug-drug interactions (pDDIs) may harm patients admitted to the Intensive Care Unit (ICU). Due to the patient's critical condition and continuous monitoring on the ICU, not all pDDIs are clinically relevant. Clinical decision support systems (CDSSs) warning for irrelevant pDDIs could result in alert fatigue and overlooking important signals. Therefore, our aim was to describe the frequency of clinically relevant pDDIs (crpDDIs) to enable tailoring of CDSSs to the ICU setting. Materials & methods: In this multicenter retrospective observational study, we used medication administration data to identify pDDIs in ICU admissions from 13 ICUs. Clinical relevance was based on a Delphi study in which intensivists and hospital pharmacists assessed the clinical relevance of pDDIs for the ICU setting. Results: The mean number of pDDIs per 1000 medication administrations was 70.1, dropping to 31.0 when considering only crpDDIs. Of 103,871 ICU patients, 38% was exposed to a crpDDI. The most frequently occurring crpDDIs involve QT-prolonging agents, digoxin, or NSAIDs. Conclusions: Considering clinical relevance of pDDIs in the ICU setting is important, as only half of the detected pDDIs were crpDDIs. Therefore, tailoring CDSSs to the ICU may reduce alert fatigue and improve medication safety in ICU patients
HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: Recommendations for personnel, policy, procedures and follow-up. A report of the Heart Rhythm Society (HRS) Task Force on catheter and surgical ablation of atrial fibrillation
During the past decade, catheter ablation of atrial fibrillation (AF) has evolved rapidly from a highly experimental unproven procedure, to its current status as a commonly performed ablation procedure in many major hospitals throughout the world. Surgical ablation of AF, using either standard or minimally invasive techniques, is also performed in many major hospitals throughout the world. The purpose of this Consensus Statement is to provide a state-of-the-art review of the field of catheter and surgical ablation of AF, and to report the findings of a Task Force, convened by the Heart Rhythm Society and charged with defining the indications, techniques, and outcomes of this procedure. The Heart Rhythm Society was pleased to develop this Consensus Statement in partnership with the European Heart Rhythm Association and the European Cardiac Arrhythmia Society. This statement summarizes the opinion of the Task Force members based on their own experience in treating patients, as well as a review of the literature, and is directed to all health care professionals who are involved in the care of patients with AF, particularly those who are undergoing or are being considered for catheter or surgical ablation procedures for AF. This statement is not intended to recommend or promote catheter ablation of AF. Rather the ultimate judgment regarding care of a particular patient must be made by the health care provider and patient in light of all the circumstances presented by that patient. In writing a "consensus" document, it is recognized that consensus does not mean that there was complete agreement among all Task Force members. We attempted to identify those aspects of AF ablation for which a true "consensus" could be identified ( Tables 1 and 2 ). Surveys of the entire Task Force were used to identify these areas of consensus. The main objective of this document is
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