Quantification of the transmural dynamics of atrial fibrillation by simultaneous endocardial and epicardial optical mapping in an acute sheep model

BACKGROUND: Therapy strategies for atrial fibrillation based on electrical characterization are becoming viable personalized medicine approaches to treat a notoriously difficult disease. In light of these approaches that rely on high-density surface mapping, this study aims to evaluate the presence of three-dimensional electrical substrate variations within the transmural wall during acute episodes of atrial fibrillation. METHODS AND RESULTS: Optical signals were simultaneously acquired from the epicardial and endocardial tissue during acute fibrillation in ovine isolated left atria. Dominant frequency, regularity index, propagation angles and phase dynamics were assessed and correlated across imaging planes to gauge the synchrony of the activation patterns compared to paced rhythms. Static frequency parameters were well correlated spatially between the endocardium and the epicardium (dominant frequency, 0.79+/-0.06 and regularity index, 0.93+/-0.009). However, dynamic tracking of propagation vectors and phase singularity trajectories revealed discordant activity across the transmural wall. The absolute value of the difference in the number, spatial stability, and temporal stability of phase singularities between the epicardial and endocardial planes was significantly greater than 0 with a median difference of 1.0, 9.27%, and 19.75%, respectively. The number of wavefronts with respect to time was significantly less correlated and the difference in propagation angle was significantly larger in fibrillation compared to paced rhythms. CONCLUSIONS: Atrial fibrillation substrates are dynamic three-dimensional structures with a range of discordance between the epicardial and endocardial tissue. The results of this study suggest that transmural propagation may play a role in AF maintenance mechanisms

Morphological variation and sensitivity to frequency of forms among native speakers of Czech

This article looks at inter-speaker variation in two environments: the genitive and locative singular cases of masculine ‘hard inanimate’ nouns in Czech, using a large-scale survey of native speakers that used two tasks to test their preferences for certain forms (acceptability) and their choices (gap filling). Our hypothesis that such variation exists was upheld, but only within limited parameters. Most biographical data (age, gender, education) played no role in respondents’ choices or preferences. Their region of origin played a small but significant role, although not the one expected. Relating the two types of tasks to each other, we found that respondents’ use of the ratings scale did not correlate to their choice of forms, but their overall strength of preference for one form over another did correlate with their choices. Inter-speaker variation does thus go some way to explaining the persistent diversity in this paradigm and arguably may contribute to its maintenance

Automated methods for the investigation of language contact, with a focus on lexical borrowing

While language contact has so far been predominantly studied on the basis of detailed case studies, the emergence of methods for phylogenetic reconstruction and automated word comparison – as a result of the recent quantitative turn in historical linguistics – has also resulted in new proposals to study language contact situations by means of automated approaches. This study provides a concise introduction to the most important approaches which have been proposed in the past, presenting methods that use (A) phylogenetic networks to detect reticulation events during language history, (B) sequence comparison methods in order to identify borrowings in multilingual datasets, and (C) arguments for the borrowability of shared traits to decide if traits have been borrowed or inherited. While the overview focuses on approaches dealing with lexical borrowing, questions of general contact inference will also be discussed where applicable

Persistent atrial fibrillation from the onset: a specific subgroup of patients with biatrial substrate involvement and poorer clinical outcome

Abstract not availableHan S. Lim, Arnaud Denis, Melissa E. Middeldorp, Dennis H. Lau, Rajiv Mahajan, Nicolas Derval, Jean-Paul Albenque, Serge Boveda, Stephan Zellerhoff, Seigo Yamashita, Benjamin Berte, Saagar Mahida, Yuki Komatsu, Matthew Daly, Laurence Jesel, Carole Pomier, Valentin Meillet, MSC, Remi Dubois, Sana Amraoui, Ashok Shah, Frédéric Sacher, Hubert Cochet, Mélèze Hocini, Pierre Jaïs, Prashanthan Sanders, Michel Haïssaguerr

Driver Domains in Persistent Atrial Fibrillation

International audienc