Search results for "electrical conduction"
showing 4 items of 24 documents
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…
Intrinsic changes on automatism, conduction, and refractoriness by exercise in isolated rabbit heart.
2001
We have studied the intrinsic modifications on myocardial automatism, conduction, and refractoriness produced by chronic exercise. Experiments were performed on isolated rabbit hearts. Trained animals were submitted to exercise on a treadmill. The parameters investigated were 1) R-R interval, noncorrected and corrected sinus node recovery time (SNRT) as automatism index; 2) sinoatrial conduction time; 3) Wenckebach cycle length (WCL) and retrograde WCL, as atrioventricular (A-V) and ventriculoatrial conduction index; and 4) effective and functional refractory periods of left ventricle, A-V node, and ventriculoatrial retrograde conduction system. Measurements were also performed on coronary…
The Heart in Fabry Disease – from Pathogenesis to Enzyme Replacement Therapy
2010
The cardiovascular involvement in Fabry disease is progressive, and accounts for one of the major reasons for abbreviated life expectancy and increased morbidity. The majority of patients develop signs and symptoms, related to heart failure and arrhythmias. Hypertrophic cardiomyopathy, in later stages combined with myocardial fibrosis, is one of the leading features. Both genders are affected, and females develop severe cardiac Fabry disease approximately 10–15 years later in life than male patients. Diastolic dysfunction and reduced longitudinal mid-wall related systolic function are the mechanical consequences of the myocardial and epithelial changes related to accumulation of the storage…
Superconductivity explained with the tools of the classical electromagnetism. Educational path for secondary school and its experimentation.
2014
The work of this thesis describes an educational path for the presentation of superconductivity at the secondary school, together with the experimentation of some particular parts of the path with high school students. The educational path that we have developed is mainly centred on the phenomenological aspects of superconductivity and has been inspired by the two fluid theory of Gorter and Casimir (1934) where a superconductor is seen as a material in which two fluids are present, the normal fluid described by the Ohm's laws, and the superconductive fluid descibed by the London equation (1935). Both the Ohm's laws and the London equation give respectively the phenomenological descriptions …