Search results for "Fibril"

Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

2006

Introduction and objectives. The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. Methods. Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. Results. Linear regression analysis showed that there was a good correlation between …

New Perspective in Atrial Fibrillation

2020

International audience; Despite a large number of publications on this subject, the pathophysiological mechanisms involved in atrial fibrillation (AF) onset and recurrence are uncertain [...]

Permanent left atrial pacing therapy may improve symptoms in heart failure patients with preserved ejection fraction and atrial dyssynchrony: a pilot…

2012

Aims Our group has recently shown that in some patients, heart failure with preserved ejection fraction (HFPEF) may be explained by ‘atrial dyssynchrony syndrome’ (ADS) due to interatrial conduction delay (IACD), a short left atrioventricular interval (LAVI), and increased left atrial (LA) stiffness. Our primary objective was to evaluate LA pacing therapy as a new treatment to restore left ventricular active filling in patients with no other known causes for HF than ADS. Methods and results Six patients with severe HFPEF with IACD (P wave duration >120 ms in lead II), short LAVI during electrophysiological studies ( 15), and no standard indication for a pacemaker were implanted with a lead …

Protective Effects of L- and D-Carnosine on R-Crystallin Amyloid Fibril Formation: Implications for Cataract Disease

2009

Mildly denaturing conditions induce bovine ?-crystallin, the major structural lens protein, to self-assemble into fibrillar structures in vitro. The natural dipeptide L-carnosine has been shown to have potential protective and therapeutic significance in many diseases. Carnosine derivatives have been proposed as potent agents for ophthalmic therapies of senile cataracts and diabetic ocular complications. Here we report the inhibitory effect induced by the peptide (L- and D-enantiomeric form) on ?-crystallin fibrillation and the almost complete restoration of the chaperone activity lost after denaturant and/or heat stress. Scanning force microscopy (SFM), thioflavin T, and a turbidimetry ass…

New Approach of Controlling Cardiac Alternans

2018

The alternans of the cardiac action potential duration is a pathological rhythm. It is considered to be relating to the onset of ventricular fibrillation and sudden cardiac death. It is well known that, the predictive control is among the control methods that use the chaos to stabilize the unstable fixed point. Firstly, we show that alternans (or period-2 orbit) can be suppressed temporally by the predictive control of the periodic state of the system. Secondly, we determine an estimation of the size of a restricted attraction's basin of the unstable equilibrium point representing the unstable regular rhythm stabilized by the control. This result allows the application of predictive control…

Atrial fibrillation is associated with cardiac hypoxia.

2008

BACKGROUND: Atrial fibrillation (AF), the most common human arrhythmia, is responsible for substantial morbidity and mortality and may be promoted by selective atrial ischemia and atrial fibrosis. Consequently, we investigated markers for hypoxia and angiogenesis in AF. METHODS: Right atrial appendages (n=158) were grouped according to heart rhythm [sinus rhythm (SR) or AF]. The degree of fibrosis and microvessel density of all patients were determined morphometrically using Sirius-Red- and CD34/CD105-stained sections, respectively. Next, sections (n=77) underwent immunostaining to detect hypoxia- and angiogenesis-related proteins [hypoxia-inducible factor (HIF)1 alpha, HIF2 alpha, vascular…

Evaluation of the Complexity of Myocardial Activation During Ventricular Fibrillation. An Experimental Study

2013

A B S T R A C T Introduction and objectives: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. Methods: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. Results: The complexity of ve…

Atrial fibrillation in high-risk patients with ischaemic stroke – Authors' reply

2017

Impact of atrial fibrillation/flutter on the in-hospital mortality of ischemic stroke patients.

2020

Stroke is the second leading cause of death worldwide. Ischemic strokes, which are caused by atrial fibrillation/flutter (AF), may be more devastating than those that occur without AF.The purpose of this study was to investigate the impact of AF on adverse events in hospitalized ischemic stroke patients and to estimate the elevated impact of AF on the occurrence of these adverse events.The nationwide German inpatient sample of the years 2005-2015 was used for this analysis. Ischemic stroke patients were identified by ICD code I63 and stratified by AF. Logistic regression models were used to investigate the impact of AF on adverse in-hospital events and adjusted for age, sex, and comorbiditi…

Variables affecting the quality of anticoagulation in atrial fibrillation patients newly initiating vitamin K antagonists: insights from the national…

2021

Abstract Aims Vitamin K antagonists (VKAs) are effective drugs reducing the risk for stroke in atrial fibrillation (AF), but the benefits derived from such therapy depend on the international normalized ratio (INR) maintenance in a narrow therapeutic range. Here, we aimed to determine independent variables driving poor anticoagulation control [defined as a time in therapeutic range (TTR) <65%] in a ‘real world’ national cohort of AF patients. Methods and results The SULTAN registry is a multicentre, prospective study, involving patients with non-valvular AF from 72 cardiology units expert in AF in Spain. At inclusion, all patients naïve for oral anticoagulation were started with VKAs…