Search results for "atrium"
showing 10 items of 69 documents
Right atrium compression by a renal cyst: a tomographic diagnosis.
2011
Correlation between atrial fibrillation driver locations and complex fractionated atrial electrograms in patients with persistent atrial fibrillation.
2018
Introduction The aim of this study was to evaluate a spatial correlation between active atrial fibrillation (AF) drivers measured by electrocardiographic imaging and complex fractionated atrial electrograms (CFAEs) in patients with persistent AF. Methods Sixteen patients with persistent AF were included. A biatrial geometry relative to an array of 252-body-surface-electrodes was obtained from a noncontrast computed tomography scan. The reconstructed unipolar AF electrograms were signal-processed (ECVUE™, CardioInsight Technologies Inc., Cleveland, OH, USA) to identify AF drivers. Before driver ablation, a biatrial mapping using the NavX system (St. Jude Medical, St. Paul, MN, USA) was perfo…
Embolic stroke, sinus rhythm and left atrial mechanical function
2004
A 64-year-old man manifested a stroke two years after restoration of sinus rhythm through a radiofrequency catheter ablation. Transesophageal echo- cardiography demonstrated the presence of a thrombus in the left atrial appendage. Left atrial volumes and different parameters of atrial emptying showed that, de- spite the persistence of the sinus rhythm, atrial mechanical function was severely impaired. After atrial ablation procedures echocardiography can be useful to stratify pa- tients according to their risk of developing embolic events and hence be of help in deciding whether or not discontinuation of anticoagulant therapy is the appropri- ate choice.
Simplifying atrial fibrillation ablation: how far can we go?
2013
The procedural end point of electrical isolation of the pulmonary veins (PVs) for the treatment of atrial fibrillation (AF) has been debated extensively. After identifying the PVs as the dominant arrhythmogenic site of paroxysmal AF, 2 fundamentally different approaches to the interventional treatment of AF were introduced. Haissaguerre et al developed a technique to electrically isolate the PVs by targeting electrophysiological (EP) breakthroughs from the left atrium to the PVs guided by a circular mapping catheter. In contrast, Pappone et al implemented an anatomical approach that used circumferential ablation lines around the PVs guided by a 3-dimensional mapping system. This latter appr…
Three dimensional reconstruction to visualize atrial fibrillation activation patterns on curved atrial geometry
2021
BackgroundThe rotational activation created by spiral waves may be a mechanism for atrial fibrillation (AF), yet it is unclear how activation patterns obtained from endocardial baskets are influenced by the 3D geometric curvature of the atrium or ‘unfolding’ into 2D maps. We develop algorithms that can visualize spiral waves and their tip locations on curved atrial geometries. We use these algorithms to quantify differences in AF maps and spiral tip locations between 3D basket reconstructions, projection onto 3D anatomical shells and unfolded 2D surfaces.MethodsWe tested our algorithms in N = 20 patients in whom AF was recorded from 64-pole baskets (Abbott, CA). Phase maps were generated by…
Simulation of the relative atomic populations of elements 1 ≤ Z ≤89 following charge exchange tested with collinear resonance ionization spectroscopy…
2019
© 2019 The Authors Calculations of the neutralisation cross-section and relative population of atomic states were performed for ions beams (1 ≤ Z ≤ 89) at 5 and 40 keV incident on free sodium and potassium atoms. To test the validity of the calculations, the population distribution of indium ions incident on a vapour of sodium was measured at an intermediate energy of 20 keV. The relative populations of the 5s 2 5p 2 P 1/2 and 5s 2 5p 2 P 3/2 states in indium were measured using collinear resonance ionization spectroscopy and found to be consistent with the calculations. Charge exchange contributions to high-resolution lineshapes were also investigated and found to be reproduced by the calc…
Nachweis von Markembolien wÄhrend Oberschenkelmarknagelungen mittels transösophagealer Echokardiographie
1989
Kardiopulmonale Komplikationen nach Marknagelosteosynthesen, insbesondere am Oberschenkel, sind bekannt. WAhrend der Nagelung einer Oberschenkelquerfraktur mit einem, geschlossenen distalen Fragment konnten durch transsophageale Echokardiographie im rechten Herzen durchstromende echogene Partikel nachgewiesen werden. Das intrakardiale Auftreten dieser Partikel stand in engem zeitlichen Zusammenhang mit dem Aufbohren der femoralen Markhohle und kann als Nachweis verschleppter Marksubstanz gedeutet werden. Die intraoperative Echokardiographie bietet sich an, Untersuchungen uber die Pathophysiologie kardiopulmonaler VerAnderungen nach Marknagel osteosynthesen durchzufuhren und die EffektivitAt…
Über das Membranpotential am Vorhof des Meerschweinchenherzens nach Hypothermie / The Membrane Potential of the Cardiac Atrium of Guinea Pigs after H…
1969
Linke Vorhofe von Meerschweinchenherzen wurden prapariert und 30 min in Tyrodelosung mit 5, 4m MK+ /l bei 35° C aquilibriert. Anschliesend wurden die Praparate 90 min bei 4–6° C von einer Tyrodelosung mit 1,35mMK+ /l umspult. Danach wurden die Vorhofe in einer Tyrodelosung mit 21,6 mM K+ /1 bei 35° C rasch wiedererwarmt.
A giant left atrium in a patient with Barlow syndrome, abnormal chordae tendineae, and perforation of the anterior mitral leaflet
2019
Isolation of the left atrial surface from cardiac multi-detector CT images based on marker controlled watershed segmentation
2006
The delineation of left atrium (LA) and pulmonary veins (PVs) anatomy from high resolution images holds importance for atrial fibrillation (AF) investigation and treatment. In this study, a semiautomatic segmentation procedure for LA and PVs inner surface from contrast enhanced CT data was developed. The procedure consists of a three dimensional marker controlled watershed segmentation applied to the external morphological gradient, followed by variable threshold surface extraction from the original intensity image. A preliminary anisotropic non-linear filtering was implemented to improve the S/N ratio of CT images. The performance of segmentation was evaluated on cardiac CT scans of 12 AF …