Search results for "Atrial"

Cerebrovascular risk factors and clinical classification of strokes

2005

Cerebrovascular risk represents a progressive and evolving concept owing to the particular distribution of risk factors in patients with ischemic stroke and in light of the newest stroke subtype classifications that account for pathophysiological, instrumental, and clinical criteria. Age represents the strongest nonmodifiable risk factor associated with ischemic stroke, while hypertension constitutes the most important modifiable cerebrovascular risk factor, confirmed by a host of epidemiological data and by more recent intervention trials of primary (HOT, Syst-Eur, LIFE) and secondary (PROGRESS) prevention of stroke in hypertensive patients. To be sure, a curious relationship exists betwee…

2015

Background and purpose Silent atrial fibrillation (AF) and tachycardia (AT) are considered precursors of ischaemic stroke. Therefore, detection of paroxysmal atrial rhythm disorders is highly relevant, but is clinically challenging. We aimed to evaluate the diagnostic value of natriuretic peptide levels in the detection of paroxysmal AT/AF in a pilot study. Methods Natriuretic peptide levels were analysed in two independent patient cohorts (162 patients with arterial hypertension or other cardiovascular risk factors and 82 patients with retinal vessel disease). N-terminal-pro-brain natriuretic peptide (NT-proBNP) and BNP were measured before the start of a 7-day Holter monitoring period car…

Non-invasive localization of atrial ectopic beats by using simulated body surface P-wave integral maps

2017

Non-invasive localization of continuous atrial ectopic beats remains a cornerstone for the treatment of atrial arrhythmias. The lack of accurate tools to guide electrophysiologists leads to an increase in the recurrence rate of ablation procedures. Existing approaches are based on the analysis of the P-waves main characteristics and the forward body surface potential maps (BSPMs) or on the inverse estimation of the electric activity of the heart from those BSPMs. These methods have not provided an efficient and systematic tool to localize ectopic triggers. In this work, we propose the use of machine learning techniques to spatially cluster and classify ectopic atrial foci into clearly diffe…

The supraventricular tachycardias: Proposal of a diagnostic algorithm for the narrow complex tachycardias

2013

AbstractThe narrow complex tachycardias (NCTs) are defined by the presence in a 12-lead electrocardiogram (ECG) of a QRS complex duration less than 120ms and a heart rate greater than 100 beats per minute; those are typically of supraventricular origin, although rarely narrow complex ventricular tachycardias have been reported in the literature.As some studies document, to diagnose correctly the NCTs is an arduous exercise because sometimes those have similar presentation on the ECG. In this paper, we have reviewed the physiopathological, clinical, and ECG findings of all known supraventricular tachycardias and, in order to reduce the possible diagnostic errors on the ECG, we have proposed …

Supervised Analysis for Phenotype Identification: The Case of Heart Failure Ejection Fraction Class

2021

Artificial Intelligence is creating a paradigm shift in health care, with phenotyping patients through clustering techniques being one of the areas of interest. Objective: To develop a predictive model to classify heart failure (HF) patients according to their left ventricular ejection fraction (LVEF), by using available data from Electronic Health Records (EHR). Subjects and methods: 2854 subjects over 25 years old with a diagnosis of HF and LVEF, measured by echocardiography, were selected to develop an algorithm to predict patients with reduced EF using supervised analysis. The performance of the developed algorithm was tested in heart failure patients from Primary Care. To select the mo…

Identification of atrial fibrillation drivers by means of concentric ring electrodes

2022

The prevalence of atrial fibrillation (AF) has tripled in the last 50 years due to population aging. High-frequency (DFdriver) activated atrial regions lead the activation of the rest of the atria, disrupting the propagation wavefront. Fourier based spectral analysis of body surface potential maps have been proposed for DFdriver identification, although these approaches present serious drawbacks due to their limited spectral resolution for short AF epochs and the blurring effect of the volume conductor. Laplacian signals (BC-ECG) from bipolar concentric ring electrodes (CRE) have been shown to outperform the spatial resolution achieved with conventional unipolar recordings. Our aimed was to…

An IoT and Fog Computing-Based Monitoring System for Cardiovascular Patients with Automatic ECG Classification Using Deep Neural Networks

2020

Telemedicine and all types of monitoring systems have proven to be a useful and low-cost tool with a high level of applicability in cardiology. The objective of this work is to present an IoT-based monitoring system for cardiovascular patients. The system sends the ECG signal to a Fog layer service by using the LoRa communication protocol. Also, it includes an AI algorithm based on deep learning for the detection of Atrial Fibrillation and other heart rhythms. The automatic detection of arrhythmias can be complementary to the diagnosis made by the physician, achieving a better clinical vision that improves therapeutic decision making. The performance of the proposed system is evaluated on a…

The 2015 European Thyroid Association Guidelines on diagnosis and treatment of endogenous subclinical hyperthyroidism

2014

Endogenous subclinical hyperthyroidism (SHyper) is caused by Graves' disease, autonomously functioning thyroid nodules and multinodular goitre. Its diagnosis is based on a persistently subnormal serum thyroid-stimulating hormone (TSH) level with free thyroid hormone levels within their respective reference intervals. In 2014 the European Thyroid Association Executive Committee, given the controversies regarding the treatment of Endo SHyper, formed a task force to develop clinical practice guidelines based on the principles of evidence-based medicine. The task force recognized that recent meta-analyses, including those based on large prospective cohort studies, indicate that SHyper is associ…

Determination of Synchronization of Electrical Activity in the Heart by Shannon Entropy Measure

2005

In this paper we propose a new index of synchronization for the study of heart’s electrical activity during atrial fibrillation (AF). The index relies on the measure of the time delays between correspondent activations in two atrial electrograms and on the characterization of their dispersion by a measure of Shannon Entropy. The algorithm was validated on simulated signals mimicking different degree of synchronization. Results showed the index was able to discriminate among different levels of organization, provided that it works on series of at least 50 activations (time resolution of almost 10 sec during AF). Moreover, we applied the algorithm to real bipolar electrograms, obtained from a…

Chronisches thromboembolisches Cor pulmonale bei schrittmacherassoziierten rechtsatrialen Thromben: Pulmonale Thrombendarteriektomie mit Elektrodenen…

2008

Life-threatening chronic cor pulmonale occurred in a 22-year-old woman with congenital 3 degrees atrioventricular block, 6 years after implantation of a pacemaker and 3 1/2 years after removal of the pacemaker (the electrodes were too firmly attached to be removed). The emboli originated from the right-atrial thrombi which had formed around the electrodes left in situ. The embolic source shrank during systemic administration of urokinase, initially 600,000 IU in 60 min, then 100,000 IU per hour, and pulmonary perfusion improved transiently. Nonetheless the patient became breathless on the slightest physical exertion. Recurrent syncopal attacks with marked increase of pulmonary artery pressu…