Search results for " heart"
showing 10 items of 741 documents
Disentangling cardiovascular control mechanisms during head-down tilt via joint transfer entropy and self-entropy decompositions
2015
A full decomposition of the predictive entropy (PE) of the spontaneous variations of the heart period (HP) given systolic arterial pressure (SAP) and respiration (R) is proposed. The PE of HP is decomposed into the joint transfer entropy (JTE) from SAP and R to HP and self-entropy (SE) of HP. The SE is the sum of three terms quantifying the synergistic/redundant contributions of HP and SAP, when taken individually and jointly, to SE and one term conditioned on HP and SAP denoted as the conditional SE (CSE) of HP given SAP and R. The JTE from SAP and R to HP is the sum of two terms attributable to SAP or R plus an extra term describing the redundant/synergistic contribution to the JTE. All q…
Cirugía de las arritmias en las cardiopatías congénitas
2008
La propia fisiopatología de las cardiopatías congénitas y el impacto de algunas correcciones quirúrgicas pueden predisponer al desarrollo de arritmias cardíacas, que incluyen taquicardia supraventricular macrorreentrante, flutter, fibrilación auricular, taquicardia auricular ectópica, taquicardia ventricular, síndrome del seno enfermo, bloqueo auriculoventricular y muerte súbita, entre otras. En la actualidad el tratamiento definitivo de estas arritmias y su profilaxis durante la corrección quirúrgica son procesos eficaces, con baja morbilidad y gran beneficio clínico para el paciente. En este trabajo se revisa el estado actual del tratamiento quirúrgico de las arritmias en las cardiopatías…
Carbon monoxide improves cardiac energetics and safeguards the heart during reperfusion after cardiopulmonary bypass in pigs
2004
Ischemia-reperfusion injury, a clinical problem during cardiac surgery, involves worsened adenosine trisphosphate (ATP) generation and damage to the heart. We studied carbon monoxide ( CO) pretreatment, proven valuable in rodents but not previously tested in large animals, for its effects on pig hearts subjected to cardiopulmonary bypass with cardioplegic arrest. Hearts of CO-treated pigs showed significantly higher ATP and phosphocreatine levels, less interstitial edema, and apoptosis of cardiomyocytes and required fewer defibrillations after bypass. We conclude that treatment with CO improves the energy status, prevents edema formation and apoptosis, and facilitates recovery in a clinical…
Morphometry and comparative histology of sinus and atrioventricular nodes in humans and pigs and their relevance in the prevention of nodal arrhythmi…
2019
The cardiac conduction system is a network structure that allows the initiation and fast propagation of electrical impulses that trigger the electrical depolarization of the myocardial tissue. The purpose of this work is to study the histological and morphometric characteristics of the different components of the sinus and atrioventricular nodes in humans and pigs and their relationship with supraventricular arrhythmias. In this study, we describe the morphometry of the sinus and atrioventricular nodes of 10 adult humans and 10 pig hearts. A computerized morphometric study has been carried out, where we determined the number of cells that compose the nodes as well as different parameters re…
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…
The "Neurocentric" Approach to Essential Hypertension: How Reliable is the Paradigm of Hyperkinetic Hypertension? A Focus on the Sympathetic Nervous …
2017
BACKGROUND: Clinic resting heart rate (RHR), is one of the cardiovascular parameters more easily measurable. In the general population RHR has been associated with total and cardiovascular mortality and higher rate of vascular events. OBJECTIVE: The case of essential hypertension is in some ways peculiar: in the past decades has often been attributed to hypertensive subjects higher values of RHR than healthy controls as a result of the effects of the different factors leading to the development of essential hypertension itself, first of all the presence of an increased tone of the sympathetic nervous system Methods: Several excellent articles debated the issue of autonomic dysfunction in es…
Patient-Specific Analysis of Ascending Thoracic Aortic Aneurysm with the Living Heart Human Model
2021
In ascending thoracic aortic aneurysms (ATAAs), aneurysm kinematics are driven by ventricular traction occurring every heartbeat, increasing the stress level of dilated aortic wall. Aortic elongation due to heart motion and aortic length are emerging as potential indicators of adverse events in ATAAs
L'ecomuseo del grano e del pane: un percorso progettuale centrato sul design
2018
La festa di S. Giuseppe, oltre che un’importante e sentita ricorrenza religiosa, è a Salemi soprattutto la “festa dei pani”; bellissime realizzazioni di alto artigianato artistico, la cui sapienza si tramanda nelle famiglie e nelle associazioni di donne che per mesi lavorano alla produzione dell’enorme quantità delle piccole e grandi forme di pane, per rivestire le costruzioni votive che accolgono il rito della cena. Nasce quindi l’idea di proporre un “Ecomuseo del grano e del pane” nel Collegio dei Gesuiti, valorizzando e riaprendo al pubblico uno spazio di grande interesse storico-architettonico. Nell’ambito della consolidata collaborazione del Comune di Salemi con il Dipartimento di Arch…
Introduction to coronary imaging with 64-slice computed tomography
2005
The aim of this article is to illustrate the main technical improvements in the last generation of 64-row CT scanners and the possible applications in coronary angiography. In particular, we describe the new physical components (X-ray tube-detectors system) and the general scan and reconstruction parameters. We then define the scan protocols for coronary angiography with the new generation of 64-row CT scanners to enable radiologists to perform a CT study on the basis of the diagnostic possibilities.
Three-Dimensional Surface Display in Blood Pool Gated SPECT
1994
In 14 patients (4 in good health and 10 with coronary heart disease) a blood pool gated single photon emission computed tomography (SPECT) was executed. The transaxial slices of the cardiac blood pool were reconstructed. A three-dimensional surface display was employed for the analysis of the tomographic data. A fixed distance, a fixed threshold (50%), and some different planes of view were employed. The test permitted visualiza tion of the ventricular and the atrial movements in all patients. The right ventricle was clearly seen in the right anterior oblique plane of view. The aortic beating was seen. In normal patients the left ventricle, clearly seen in left anterior oblique plane, shra…