• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 2
  • Tagged with
  • 6
  • 6
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The 'athletic heart' : insights from modern imaging tools in Caucasian and West African athletes

Segun, Utomi Victor January 2015 (has links)
A seminal study by Morganroth et al (1975) demonstrated a differential pattern of cardiac adaptation with prolonged exercise training; of eccentric pattern of left ventricular hypertrophy (LVH) in endurance trained athletes (ET) and concentric LVH in resistance trained athletes (RT). Specific inconsistencies related to the nature of any adaptation to RT; the value of new imaging technologies; the relative importance of scaling of cardiac data for differences in body size; the impact of training on the right ventricle (RV) and the fit of differential pattern of adaptation in athletes with Black ethnicity have driven the rationale for the studies included in this thesis. Study one employed meta-analysis techniques to critically evaluate the evidence base supporting or refuting that MH exists in elite male Caucasian ET & RT. Modern echocardiographic techniques were used to test whether a dichotomous LV and RV structural as well as global and regional functional adaptation was apparent in elite Caucasian ET & RT in studies 2 & 3. The final study (exploratory) was to characterize the athletic heart phenotype in a homogenous population of elite RT of West African origin (WRT) to provide new insight in relation to cardiac adaptation and ECG characteristics in non-Caucasian athlete groups. Allometric scaling approach was deployed to index LV and RV data for individual body variance in body size. The novel findings of this thesis; larger LV data in ET (LVMg: ET 232 (200 to 260), RT 220 (205 to 234), CT 166 (145 to 186)) but no concentric hypertrophy in RT within the meta-analysis, predominance of normal geometry in male athletes (65% of ET and 95% of RT) and the lack of concentric pattern of hypertrophy in RT in a cross-sectional study; no RV adaptation in RT athletes (RVD1mm: ET 45 ± 5 (39 to 57), RT 40 ± 5 (32 to 51) CT 39 ± 4 (31 to 45)); no LV or RV adaptation in WRT athletes; the importance of appropriate scaling of cardiac parameters; provide a useful re-evaluation of concepts and models in the athletic heart literature. The findings have important implications for cardiovascular screening of athletes.
2

A sequential evaluation of left ventricular function in asymptomatic and symptomatic patients with chronic severe aortic regurgitation

Sarembock, Ian J 24 July 2017 (has links)
The optimal timing of valve replacement surgery in chronic severe aortic regurgitation (AR) has remained a major clinical problem in the management of these patients. Although the onset of symptoms is the generally accepted indication for aortic valve replacement (AVR), the unpredictable development of pre-symptomatic left ventricular (LV) dysfunction as a result of prolonged volume overload has resulted in numerous reports attempting to formulate a risk profile for these patients. Although aortic root and LV cineangiography have been the "gold standard" for defining the severity of AR and its effect on LV performance, serial follow-up by these means is impractical. More recently numerous non-invasive measures of LV size (echocardiogram) and function both at rest and on exercise (echocardiogram and equilibrium radionuclide angiocardiography., ERNA) have been serially utilised~ In these endeavours, the thinking has been clouded by a tendency to equate these two measures and failing to appreciate that apparent preoperative LV dysfunction (particularly on exercise) may be rapidly reversible by AVR and the consequent changes in LV loading conditions. This study was a prospective, sequential evaluation of left ventricular function using both non-invasive and invasive techniques in symptomatic and asymptomatic patients with isolated chronic, severe (4+) AR at cardiac catheterisation. The aims of the study were to (I) Identify differences in the clinical, echocardiographic, resting and exercise haemodynamic and I radionuclide measures of left ventricular function in symptomatic and asymptomatic patients with chronic severe A.R. with particular reference to the incidence of presymptomatic development of left ventricular dysfunction. (II) Critically evaluate the role of exercise stress (both isotonic and isometric) in the assessment of patients with chronic severe A.R. (III) Evaluate the influence of time (sequential studies) on the haemodynamic burden in asymptomatic patients. (IV) Study the impact of successful aortic valve replacement on the reversibility of abnormal pre-operative LV function in an attempt to predict which patients would benefit from this therapeutic intervention and whether operation for symptoms alone is the correct clinical practice.
3

Avaliação morfogeométrica do ventrículo esquerdo e do anel valvar mitral na cardiomiopatia dilatada isquêmica ou idiopática: estudo comparativo computadorizado / Morphogeometric evaluation of left cardiac ventricle and mitral valval ring in dilated ischemic and idiopathic cardiomyopathies: computer assisted comparative study

Juliani, Paulo Sergio 09 January 2009 (has links)
INTRODUÇÃO: O conhecimento anatômico desempenha importante papel no desenvolvimento de técnicas diagnósticas e cirúrgicas. Com esse objetivo, na área cardiológica, se mostra fundamental para o entendimento do processo de remodelamento cardíaco que acompanha as cardiomiopatias dilatadas (CMD) tanto isquêmicas (CMDIsq) como idiopáticas (CMDId), de modo particular do ventrículo esquerdo (VE) e sua correlação com alterações do anel atrioventricular esquerdo, levando a graus variáveis de insuficiência cardíaca (IC). OBJETIVOS: Os objetivos desta pesquisa são: 1) Obter medidas do anel atrioventricular esquerdo (mitral) e do ventrículo esquerdo em corações normais, com CMDIsq ou CMDId, comparando-as entre si; 2) Analisar a proporcionalidade entre segmentos da câmara ventricular esquerda dos corações com CMDIsq ou CMDId em relação ao normal; 3) Determinar a esfericidade ou não da câmara ventricular esquerda nos corações com CMDIsq ou CMDId. MÉTODO: Foram analisados 43 corações humanos, divididos em três grupos: NORMAL (n=10), CMDIsq (n=15) e CMDId (n=18). De posse da medida da distância do sulco atrioventricular posterior até o ápice do VE, foram realizados cortes transversais baso-apicais seqüenciais e, após digitalização dos mesmos, por meio de método computadorizado, foram obtidas medidas perimetrais e espessura das paredes. Empregando-se o mesmo método, mensurou-se o perímetro do anel mitral. Foram criados índices de proporção porcentual entre os perímetros dos segmentos provenientes dos cortes do VE, comparando-os intergrupos. Nos dilatados os perímetros segmentares mensurados foram comparados com os perímetros esperados se considerássemos a câmara ventricular como uma esfera perfeita. Realizou-se a análise estatística dessas medidas e índices. RESULTADOS: O perímetro do anel mitral teve o seguinte resultado: somente o grupo CMDIsq teve média significativamente maior que o grupo NORMAL e houve baixo coeficiente de correlação com os perímetros ventriculares segmentares nos corações dilatados. Distância do sulco atrioventricular até o ápice do VE: CMDId = CMDIsq > NORMAL. Perímetros segmentares ventriculares basais (PerB), equatoriais (PerE) e apicais (PerA): grupo NORMAL-> PerE = PerB > PerA; grupos CMDId e CMDIsq- > PerE > PerB > PerA, sendo que o grupo CMDId teve essas 3 medidas maiores que o grupo CMDIsq e ambos tiveram essas 3 medidas maiores que o grupo NORMAL. Nos 3 grupos as medidas de espessura das paredes ventriculares foram iguais estatisticamente. O índice de proporção perimetral PerB/PerE foi igual nos 3 grupos, enquanto o índice PerA/PerE foi igual entre os corações dilatados, mas em ambos foi menor que no grupo NORMAL. Todos perímetros segmentares ventriculares dos corações dilatados foram menores do que os calculados segundo a fórmula da esfera. CONCLUSÕES: 1) O anel atrioventricular esquerdo dilata-se na CMDIsq, sendo essa alteração independente da dilatação dos três segmentos do VE; 2) Os corações com CMDId e CMDIsq desenvolvem uma similar dilatação longitudinal do VE; 3) Ocorre uma dilatação trans versal do VE nessas afecções, sendo essa maior nos corações com CMDId; 4) A espessura das paredes ventriculares esquerdas dos corações com CMDIsq ou CMDId não se altera quando comparada aos corações normais; 5) A dilatação transversal da câmara ventricular esquerda nos corações com CMD não se dá de forma proporcional ao longo do seu eixo longitudinal, sendo mais acentuada nas regiões basal e equatorial; 6) A câmara ventricular esquerda nos corações com CMD de origem isquêmica ou idiopática não apresenta formato esférico. / BACKGROUND: Anatomic knowledge is the cornerstone for the development of surgical and diagnostic image techniques and for understanding pathological entities. Understanding cardiac anatomy is essential for understanding cardiac remodeling in both ischemic and idiopathic dilated cardiomyopathies. Dysfunction in the physiological relationship between the morphology of left ventricle and its mitral ring plays an important role in the cardiac insufficiency etiopathogenesis. OBJECTIVES: 1) To compare morphology of left ventricle and its mitral ring among normal, ischemic and idiopathic dilated cardiomyophatic anatomic specimens; 2) To compare intra specimen ventricular segmental perimeters relationships between normal and dilated specimens; 3) To verify the presence of the spheroid shape of left ventricular chamber in dilated specimens. METHODS: It was analyzed 43 specimens of human hearts, classified in three groups: normal (n=10), dilated due to ischemic (n=15) or idiopathic cardiomyopathies (n=18). Several lengths were measured: the length from the posterior atrioventricular sulcus to the ventricular apex in the intact specimen; followed by three sequential transversal ventricular slicing in the basal, equatorial and apical level. Digital pictures were taken from these slices, in order to be analyzed in a computer assisted fashion. Internal perimeter and ventricular walls width of each slice were measured, as well the mitral ring perimeter. The three intra group perimeters were compared and correlated between themselves. Basal, equatorial and apical perimeter of each group was compared to their correspondent pairs inter groups. Regarding intra group relationships, for a given group, each slice perimeter was measured and considered as a percentage of the equatorial slice (index). This percentage was compared inter groups. Three perimeters were evaluated in both dilated groups, each one was compared to its expected value when considering left ventricular chamber as a perfect sphere (hypothesis). Measurements and index statistical analysis was performed. RESULTS: Mitral ring perimeter was longer than the NORMAL group only in ischemic group. There was a low correlation coefficient between mitral ring perimeter and ventricular segmental perimeters in both dilated groups. Longitudinal length from the left atrioventricular sulcus until the apex was similar in dilated specimens and higher compared to the normal group. Regarding sequential perimeters of ventricular slices in the normal specimens, the equatorial perimeter was as long as the basal ones, but both of them longer than the apical one. In the other hand, for dilated specimens, equatorial diameter was the longest one and apic al the smallest one. Comparing ventricular slices perimeters between dilated groups, all the perimeters lengths were longer in the idiopathic group than in the ischemic one. All the ventricular slices perimeters were longer for both dilated groups than for the normal group. There was no difference of ventricular wall width between groups. The proposed index of proportional perimeter: considering the proportion between basal and equatorial perimeter, there was no difference between any groups; but considering the proportion between apical and equatorial perimeter, dilated specimens displayed a lower index when compared to normal specimens. All the observed ventricular slice perimeters were smaller than the hypothetical (sphere) expected ones in both dilated groups. CONCLUSIONS: 1) Left atrioventricular ring dilatation occurs in ischemic dilated cardiomyopathy and it is independent of the dilatation of segments (apical, basal and equatorial) ventricular; 2) Longitudinal left ventricular dilatation is similar between dilated groups; 3) A transversal ventricular chamber dilatation was observed in dilated diseases and it is greater in the idiopathic disease; 4) The left ventricular wall widths in both dilated cardiomyopathies were similar to normal hearts; 5) Transversal dilatation of left ventricular chamber in both dilated cardiomyopathies is not proporcional along their longitudinal axis because it is more accentuated in equatorial and basal regions; 6) Left ventricular chamber in both dilated cardiomyopathies does not keep spherical shape.
4

Avaliação morfogeométrica do ventrículo esquerdo e do anel valvar mitral na cardiomiopatia dilatada isquêmica ou idiopática: estudo comparativo computadorizado / Morphogeometric evaluation of left cardiac ventricle and mitral valval ring in dilated ischemic and idiopathic cardiomyopathies: computer assisted comparative study

Paulo Sergio Juliani 09 January 2009 (has links)
INTRODUÇÃO: O conhecimento anatômico desempenha importante papel no desenvolvimento de técnicas diagnósticas e cirúrgicas. Com esse objetivo, na área cardiológica, se mostra fundamental para o entendimento do processo de remodelamento cardíaco que acompanha as cardiomiopatias dilatadas (CMD) tanto isquêmicas (CMDIsq) como idiopáticas (CMDId), de modo particular do ventrículo esquerdo (VE) e sua correlação com alterações do anel atrioventricular esquerdo, levando a graus variáveis de insuficiência cardíaca (IC). OBJETIVOS: Os objetivos desta pesquisa são: 1) Obter medidas do anel atrioventricular esquerdo (mitral) e do ventrículo esquerdo em corações normais, com CMDIsq ou CMDId, comparando-as entre si; 2) Analisar a proporcionalidade entre segmentos da câmara ventricular esquerda dos corações com CMDIsq ou CMDId em relação ao normal; 3) Determinar a esfericidade ou não da câmara ventricular esquerda nos corações com CMDIsq ou CMDId. MÉTODO: Foram analisados 43 corações humanos, divididos em três grupos: NORMAL (n=10), CMDIsq (n=15) e CMDId (n=18). De posse da medida da distância do sulco atrioventricular posterior até o ápice do VE, foram realizados cortes transversais baso-apicais seqüenciais e, após digitalização dos mesmos, por meio de método computadorizado, foram obtidas medidas perimetrais e espessura das paredes. Empregando-se o mesmo método, mensurou-se o perímetro do anel mitral. Foram criados índices de proporção porcentual entre os perímetros dos segmentos provenientes dos cortes do VE, comparando-os intergrupos. Nos dilatados os perímetros segmentares mensurados foram comparados com os perímetros esperados se considerássemos a câmara ventricular como uma esfera perfeita. Realizou-se a análise estatística dessas medidas e índices. RESULTADOS: O perímetro do anel mitral teve o seguinte resultado: somente o grupo CMDIsq teve média significativamente maior que o grupo NORMAL e houve baixo coeficiente de correlação com os perímetros ventriculares segmentares nos corações dilatados. Distância do sulco atrioventricular até o ápice do VE: CMDId = CMDIsq > NORMAL. Perímetros segmentares ventriculares basais (PerB), equatoriais (PerE) e apicais (PerA): grupo NORMAL-> PerE = PerB > PerA; grupos CMDId e CMDIsq- > PerE > PerB > PerA, sendo que o grupo CMDId teve essas 3 medidas maiores que o grupo CMDIsq e ambos tiveram essas 3 medidas maiores que o grupo NORMAL. Nos 3 grupos as medidas de espessura das paredes ventriculares foram iguais estatisticamente. O índice de proporção perimetral PerB/PerE foi igual nos 3 grupos, enquanto o índice PerA/PerE foi igual entre os corações dilatados, mas em ambos foi menor que no grupo NORMAL. Todos perímetros segmentares ventriculares dos corações dilatados foram menores do que os calculados segundo a fórmula da esfera. CONCLUSÕES: 1) O anel atrioventricular esquerdo dilata-se na CMDIsq, sendo essa alteração independente da dilatação dos três segmentos do VE; 2) Os corações com CMDId e CMDIsq desenvolvem uma similar dilatação longitudinal do VE; 3) Ocorre uma dilatação trans versal do VE nessas afecções, sendo essa maior nos corações com CMDId; 4) A espessura das paredes ventriculares esquerdas dos corações com CMDIsq ou CMDId não se altera quando comparada aos corações normais; 5) A dilatação transversal da câmara ventricular esquerda nos corações com CMD não se dá de forma proporcional ao longo do seu eixo longitudinal, sendo mais acentuada nas regiões basal e equatorial; 6) A câmara ventricular esquerda nos corações com CMD de origem isquêmica ou idiopática não apresenta formato esférico. / BACKGROUND: Anatomic knowledge is the cornerstone for the development of surgical and diagnostic image techniques and for understanding pathological entities. Understanding cardiac anatomy is essential for understanding cardiac remodeling in both ischemic and idiopathic dilated cardiomyopathies. Dysfunction in the physiological relationship between the morphology of left ventricle and its mitral ring plays an important role in the cardiac insufficiency etiopathogenesis. OBJECTIVES: 1) To compare morphology of left ventricle and its mitral ring among normal, ischemic and idiopathic dilated cardiomyophatic anatomic specimens; 2) To compare intra specimen ventricular segmental perimeters relationships between normal and dilated specimens; 3) To verify the presence of the spheroid shape of left ventricular chamber in dilated specimens. METHODS: It was analyzed 43 specimens of human hearts, classified in three groups: normal (n=10), dilated due to ischemic (n=15) or idiopathic cardiomyopathies (n=18). Several lengths were measured: the length from the posterior atrioventricular sulcus to the ventricular apex in the intact specimen; followed by three sequential transversal ventricular slicing in the basal, equatorial and apical level. Digital pictures were taken from these slices, in order to be analyzed in a computer assisted fashion. Internal perimeter and ventricular walls width of each slice were measured, as well the mitral ring perimeter. The three intra group perimeters were compared and correlated between themselves. Basal, equatorial and apical perimeter of each group was compared to their correspondent pairs inter groups. Regarding intra group relationships, for a given group, each slice perimeter was measured and considered as a percentage of the equatorial slice (index). This percentage was compared inter groups. Three perimeters were evaluated in both dilated groups, each one was compared to its expected value when considering left ventricular chamber as a perfect sphere (hypothesis). Measurements and index statistical analysis was performed. RESULTS: Mitral ring perimeter was longer than the NORMAL group only in ischemic group. There was a low correlation coefficient between mitral ring perimeter and ventricular segmental perimeters in both dilated groups. Longitudinal length from the left atrioventricular sulcus until the apex was similar in dilated specimens and higher compared to the normal group. Regarding sequential perimeters of ventricular slices in the normal specimens, the equatorial perimeter was as long as the basal ones, but both of them longer than the apical one. In the other hand, for dilated specimens, equatorial diameter was the longest one and apic al the smallest one. Comparing ventricular slices perimeters between dilated groups, all the perimeters lengths were longer in the idiopathic group than in the ischemic one. All the ventricular slices perimeters were longer for both dilated groups than for the normal group. There was no difference of ventricular wall width between groups. The proposed index of proportional perimeter: considering the proportion between basal and equatorial perimeter, there was no difference between any groups; but considering the proportion between apical and equatorial perimeter, dilated specimens displayed a lower index when compared to normal specimens. All the observed ventricular slice perimeters were smaller than the hypothetical (sphere) expected ones in both dilated groups. CONCLUSIONS: 1) Left atrioventricular ring dilatation occurs in ischemic dilated cardiomyopathy and it is independent of the dilatation of segments (apical, basal and equatorial) ventricular; 2) Longitudinal left ventricular dilatation is similar between dilated groups; 3) A transversal ventricular chamber dilatation was observed in dilated diseases and it is greater in the idiopathic disease; 4) The left ventricular wall widths in both dilated cardiomyopathies were similar to normal hearts; 5) Transversal dilatation of left ventricular chamber in both dilated cardiomyopathies is not proporcional along their longitudinal axis because it is more accentuated in equatorial and basal regions; 6) Left ventricular chamber in both dilated cardiomyopathies does not keep spherical shape.
5

Biobehavioral triggers of cardiac arrhythmia during daily life : the role of emotion, physical activity, and heart rate variability /

McCeney, Melissa Kay. January 2004 (has links) (PDF)
Thesis (Ph. D.)--Uniformed Services University of the Health Sciences, 2004. / Typescript (photocopy).
6

Atypical depression, body mass, and left vetricular mass analysis of data from CARDIA /

Schwartz, Sari D. January 2005 (has links) (PDF)
Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).

Page generated in 0.0945 seconds