Spelling suggestions: "subject:"echocardiography "" "subject:"chocardiography ""
291 |
The use of echocardiography in predicting left ventricle thrombus in patients with idiopathic dilated cardiomyopathy at Chris Hani Baragwanath HospitalFerreira Dos Santos, Claudia Marisa Goncalves 21 January 2013 (has links)
Submitted in fulfillment of the requirements for the Degree of Masters in Technology: Cardiology, Durban University of Technology, 2012. / Cardiomyopathies and their resultant heart failure (HF) remain a
major cause of cardiovascular morbidity and mortality (Wood and Picard, 2004).
Idiopathic dilated cardiomyopathy (IDCMO) is a primary myocardial disease of
unknown cause, characterized by left ventricular (LV) or biventricular dilatation
and impaired myocardial contractility. Dilated cardiomyopathy (DCMO), along
with rheumatic heart disease and hypertension (HPT), is one of the leading
causes of HF in Africa. In fact, in an epidemiology study of 884 patients in
Soweto, IDCMO was the second major cause of HF. Thirty five percent of
patients in the study, with HF, had IDCMO (Sliwa, Damasceno, Mayosi, 2005).
Methodology: Patients referred to the cardiomyopathy (CMO) clinic at Chris
Hani Baragwanath hospital, situated in the echocardiographic lab, were recruited,
provided they satisfied the exclusion and inclusion criteria and were enrolled after
obtaining voluntary informed consent. From May 2009 to September 2010, 70
patients with IDCMO were recruited for this trial. Patients with DCMO were
identified by means of echocardiographic criteria which included a left ventricular
ejection fraction (LVEF) of less than 45% and an end diastolic dimension (EDD)
of greater than of 52 mm (2D in long parasternal axis).
Results: In the present study the prevalence of left ventricular (LV) thrombus in
patients with IDCMO was 18.6%. When using Univariate logistic regression, the
only independent predictors of LV thrombus formation was LVEF and age.
However, when multivariate logistic regression analysis was applied to the data,
the only predictor with a significant association was age. The reason for this is
not clear. It is postulated that perhaps younger patients have differences in the
pathophysiology of their disease such as a greater smoldering inflammatory
component which may therefore predispose them to thrombus formation. For
example the presence of IL-6 may be important in the formation of LV clot in
cases of LV dysfunction (Sosin, Bhatia, Davis, Lip, 2003). The association
between LVEF and LV thrombus was borderline significant.
Conclusion: The prevalence of LV thrombus formation in this cohort of patients
with IDCMO was 18.6%. Echocardiographic parameters alone cannot predict
which patients are more likely to develop thrombus formation. / National Research Foundation / M
|
292 |
Prädiktoren der linksatrialen Thromben und Spontanechokontrastierung bei Patienten mit Vorhofflimmern vor geplanter Kardioversion – Eine monozentrische Erfahrung – eine systematische Analyse / Predictors for left atrial thrombi and spontaneous echo contrast in patients with atrial fibrillation before planed cardioversion - A monocentric experience - A systematic analysisBejinariu, Alexandru Gabriel 06 February 2018 (has links)
No description available.
|
293 |
Outcome of patients with severe aortic stenosis – A retrospective follow-up studyAhlén, Caroline January 2008 (has links)
Aortic stenosis is the most common valvular disease in the adult population. A significant aortic stenosis is a serious condition, and if a symptomatic patient is not operated on, it may in most cases cause death. We have examined how many aortic stenoses that were diagnosed during one year, and a follow-up of the patients was also performed. We found 77 patients with significant aortic stenosis with a mean age of 76±13 years. At the time of follow-up 30 (39%) patients, aged between 29-85 years, had been surgically treated with implantation of a valve prosthesis within 2-23 months after the initial examination. At this initial examination 14 of the 30 patients who later underwent surgery had no symptoms. A coronary bypass operation was also performed on seven patients. Postoperative complications were observed in six patients, but none of them was fatal. At the initial examinations there were 26 (34%) patients with a significant aortic stenosis and symptoms who were not treated surgically. The main reason why these patients were not operated was high age, unwillingness, or severe left ventricular dysfunction. This study indicates the importance of repeated clinical and echocardiograpic examinations in patients with aortic stenosis. Almost half of the patients, that later underwent surgery, had no symptoms at the initial examination, but later developed symptoms which made surgery necessary. In one third of the patients no surgery was performed in spite of clinical symptoms.
|
294 |
La caractérisation du speckle sur des images échocardiographiques afin de définir des indices diagnostiques de l'amylose cardiaque et personnaliser un modèle numérique du coeur / Speckle Characterisation in Echocardiographic Images to Aid in the Diagnosis of Cardiac AmyloidosisDamerjian, Vera 05 December 2016 (has links)
L’Hypertrophie Ventriculaire Gauche (HVG) est actuellement mise en évidence par échographie. Cet examen fournit des informations anatomo-fonctionnelles mais ne permet pas de déterminer l’étiologie des HVG, ce qui engendre de graves erreurs de diagnostic et de prise en charge thérapeutique. Les HVG sont classiquement séparées en 2 catégories :1. pathologies hypertrophiques induites par la modification structurelle et fonctionnelle des cardiomyocites qui tend à compenser des insuffisances cardiaques liées par exemple à des problèmes d’hypertension artérielle, de rétrécissement aortique ou de CardioMyopathies Hypertrophiques sarcomériques ;2. pathologies infiltratives correspondant au dépôt de protéines dans la matriceextracellulaire principalement dues à différentes formes d’amyloses cardiaquesNotre hypothèse est que les différents mécanismes physiopathologiques (hypertrophique ou infiltratif) pourraient se traduire dans l’image par des propriétés spécifiques du speckle échographique. Nous avons donc développé un travail d’analyse de la texture de ces images afin de discriminer les différentes HVG.Dans cette étude, la base de données de 4795 images est divisée en une base d’apprentissage de 3770 images et une base de test de 1025 images. L’analyse de texture des images est faite par les ondelettes de Gabor avec 8 orientations, 7 tailles et 5 niveaux de décomposition. Ensuite, les caractéristiques statistiques de premier et deuxième ordre sont extraites des images. Le nombre des caractéristiques est réduit pour la base d’apprentissage en appliquant l’Analyse en Composantes Principales (ACP) suivie par l’analyse discriminante linéaire (ADL) pour une séparation supervisée des classes. Les caractéristiques extraites pour la base de test sont projetées sur les vecteurs propres sélectionnés au cours de l’apprentissage. L’ADL est appliquée à ce niveau pour la classification des données du test et la qualité de cette classification est évaluée. Les résultats obtenus sont bons (qualité totale de classification de 95,51%) et sont suivis d’une étape de cross-validation afin de vérifier la robustesse de notre méthode. A cette étape, les bases de données de l’apprentissage et du test sont mélangées et 50 combinaisons différentes sont évaluées. La même méthode décrite précédemment est appliquée. La cross-validation montre une variation de la qualité de classification (entre 30% et 99.96%) probablement due à l’hétérogénéité des caractéristiques texturelles pour les patients d’une même classe que l’on peut expliquer par des degrés différents d’avancement dans la pathologie.Ces travaux montrent qu’une analyse de texture des images échocardiographiques peut permettre de déterminer des bio-marqueurs aptes à discriminer différentes cardiopathies qui s’expriment par une HVG. Ce résultat peut avoir des retombées très importantes dans la détection précoce des amyloses cardiaques, maladies engendrant un fort taux de mortalité souvent dû à un retard de diagnostic et prise en charge des patients par un centre expert / Left-Ventricular Hypertrophy (LVH) is currently detected through echocardiography. The latter imaging modality provides anatomical and functional information. However, it does not allow the determination of the HVG etiology. This can, in turn, lead to dangerous errors in the diagnosis and treatment planning of the disease. LVH pathologies are separated into two categories:- Hypertrophic pathology caused by the structural and functional modification of cardiomyocytes that lead to cardiac failure related, for example, to arterial hypertension problems, aortic narrowing or sarcomeric hypertrophic cardiomyopathies.- Infiltrative pathologies corresponding to protein deposits on the extracellular matrix, mainly due to different forms of cardiac amyloidosisOur hypothesis is that different physiopathological mechanisms (hypertrophic or infiltrative) can be translated in the image through properties specific to echographic speckle. We have therefore developed the work of texture analysis of such images in order to discriminate the different types of LVH.In this study, the database of 4795 images is divided into a learning database of 3770 images and another testing database of 1025 images. The textural analysis of these images is done using Gabor wavelets with 8 orientations, 7 sizes and 5 decomposition levels. Next, the statistical characteristics of first and second orders are extracted from the filtered images. The number of characteristics is reduced for the learning database by applying Principal Component Analysis (PCA) followed by Linear Discriminant Analysis (LDA) for a supervised separation of the classes. The extracted characteristics for the test database are projected on the eigenvectors selected in the learning step. LDA is applied at this level for the test data classification, and the quality of this classification is evaluated. The obtained results are good (total classification quality of 95.51%). A step of cross-validation follows in order to verify the robustness of our method. At this stage, the learning and testing databases are mixed, and 50 different combinations are evaluated. The same method described previously is then applied. The cross-validation shows a variation in the classification quality (between 30% and 99.96%) probably due to the heterogeneity of the texture characteristics for the patients of the same class explained by different disease advancement stages.This work shows that the textural analysis of echocardiographic images can permit the determination of bio-markers suitable to discriminate different LVH cardiopathies. Our results can have a very important impact on the early detection of cardiac amyloidosis, a pathology causing a considerable rate of mortality often due to a belated diagnosis and support by the centers of expertise
|
295 |
Sialylation and Cardiomyocyte Complex <i> N </i> -Glycosylation Protect Against Dilated Cardiomyopathy and Heart FailureDeng, Wei 29 June 2016 (has links)
Dilated cardiomyopathy (DCM) is the third most common cause of heart failure, often associated with arrhythmias and sudden cardiac death if not controlled. Metabolic and/or environmental factors, such as alcohol abuse, obesity, diabetes and Chagas disease, alter glycoprotein glycosylation, can lead to DCM. Inherited genetic disease, such as the human congenital disorders of glycosylation (CDG), causes multi-system manifestations including DCM. Non-congenital changes in glycosylation are also occurred in humans with and in animal models of DCM and heart failure. However, mechanisms responsible for glyco-dependent DCM are not understood. Here we sought to investigate the impact of sialylation and N-glycosylation in cardiac function.
Partial reduction of N-α2,3-sialylation achieved through ST3Gal4 deletion (ST3Gal4-/-) led to adult late-onset DCM. The DCM symptoms progressed gradually, developing thinner left ventricular walls and dilation of all four chambers by 18-month old, but with preserved systolic function. Transverse aortic constriction (TAC) was used as a chronic stressor on 16-20 week old mice to determine whether the ability of the ST3Gal4-/- heart to compensate against pathologic insult is compromised. TAC’d ST3Gal4-/- mice presented with insufficient hypertrophy and reduced systolic function that deteriorated into congestive HF within six weeks post-surgery, while constricted WT hearts remained well-adapted throughout (ejection fraction, ST3Gal4-/-=34±5.2%; WT =53.8±7.4%; p<0.05).Calcineurin expression was decreased in ST3Gal4-/- (compared to TAC’d WT), contributed to the maladaptation of TAC’d ST3Gal4-/-.
In order to better understand the role of glycosylation on cardiac function, we generated a cardiomyocyte specific knockout (αMHC-Cre) of glycosyltransferase responsible for synthesizing complex and hybrid N-glycans, Mgat1, (Mgat1CKO). Similar to but much more severe than that observed in ST3Gal4-/-, Mgat1CKO developed early-onset of DCM, late adult mortality, severely impaired cardiac systolic and diastolic function and frequent arrhythmias. Marked sex-difference in cardiac phenotype was observed in this autosomal gene (Mgat1) deletion, with male Mgat1CKO more severely affected. Both ST3Gal4 and Mgat1 did not participate in murine cardiogenesis, evidenced by normal litter size, Mendelian distribution of genotypes, no septal defect or vessel deformation under autopsy or echocardiography.
In conclusion, we provided here the first and direct evidence of desialylation-elicited idiopathic dilated cardiomyopathy (DCM), reporting the cardiac phenotype of ST3Gal4-/-and cardiac-specific knockout of Mgat1. Our data showed sialylation and complex N-glycosylation are essential for cardiac function, and reduced N-glycosylation or sialylation leads to DCM development, contractile dysfunction and arrhythmia.
|
296 |
Point of care-Ultraschall versus Röntgen-Thorax zur Lagekontrolle zentralvenöser Katheter / Point of care echocardiography versus chest radiography for central venous catheter position assessmentMavropoulou, Eirini 25 September 2017 (has links)
No description available.
|
297 |
Cardio-pulmonary function in familial amyloidosis with polyneuropathy : a clinical study of cases from northern SwedenOlofsson, Bert-Ove January 1982 (has links)
Familial amyloidosis with polyneuropathy (FAP) was first reported from Portugal in 1952, but since then this syndrome has been recognized in many countries including Sweden. In this investigation cardiac and pulmonary functions in the Swedish variety of FAP were studied. A retrospective survey of the ECG findings in 71 patients showed a high prevalence of atrioventricular (38%) and intraventricular (41%) conduction defects, and also a high prevalence of atrial fibrillation (14%). In several patients a progression in the conduction defects to advanced disturbances could be observed and 10 out of 71 patients (14%) in the present series required pacemaker treatment. A histopathological study of the atrioventricular part of the conduction system showed marked amyloid infiltration in each case, which may explain the high prevalence of conduction defects. In an échocardiographie study which emcompassed 22 consecutive patients, all but those two patients with the shortest duration of symptomatic disease showed abnormal features. The most frequent and characteristic findings were hypertrophy of the interventricular septum (86%) and a hyperrefractile appearance of the iryocardium (68%). This unusual association of échocardiographie features is considered almost diagnostic of cardiac amyloidosis. A hemodynamic study showed an essentially normal systolic heart function, but in several patients there were signs of impaired diastolic function with increased myocardial rigidity. Several patients showed signs of obstruction of the ventricular outflow tracts. This finding, as well as the échocardiographie features, is in accordance with altered anatomical and functional properties of the interventricular septum. The major pulmonary function abnormalities were decreased maximum respiratory pressure which indicate that the neuropathy in FAP involves the respiratory musculature, and impaired diffusing capacity consistent with an alveo-capillary block caused by amyloid deposits. / digitalisering@umu
|
298 |
Placental insufficiency and fetal heart: Doppler ultrasonographic and biochemical markers of fetal cardiac dysfunctionMäkikallio, K. (Kaarin) 28 July 2002 (has links)
Abstract
The first aim of this study was to investigate the relationship between Doppler ultrasonographic parameters and biochemical markers of human fetal cardiac dysfunction and myocardial cell damage in pregnancies complicated by placental insufficiency and/or fetal growth restriction. Our second aim was to examine fetal central and peripheral hemodynamic characteristics associated with retrograde aortic isthmus net blood flow.
Fetuses with significant myocardial cell damage (cTnT > 0.10 ng/ml) had increased pulsatility in the blood velocity waveforms of ductus venosus, left hepatic vein and inferior vena cava, and had more often atrial pulsations in the umbilical vein. Their umbilical artery NT-proANP concentrations were higher than in fetuses without myocardial cell damage. The proportion of left ventricular cardiac output of the combined cardiac output was greater and the corresponding proportion of the right ventricle was less than in fetuses with only increased NT-proANP levels ( > 1145 pmol/l). Tricuspid regurgitation was present more often and the right ventricular fractional shortening was less in fetuses with myocardial cell damage than in fetuses with normal umbilical artery cTnT levels. In fetuses with placental insufficiency and/or growth restriction (n = 48), umbilical artery NT-proANP concentrations showed a significant positive correlation with ductus venosus, left hepatic vein and inferior vena cava pulsatility index values for veins. Fetuses with placental insufficiency and antegrade aortic isthmus net blood flow demonstrated a shift in their right ventricular cardiac output from the pulmonary to the systemic circulation, and foramen ovale volume blood flow made up the majority of the left ventricular cardiac output. Fetuses with retrograde aortic isthmus net blood flow failed to demonstrate these changes, and they had signs of increased left atrial pressure. In addition, right ventricular fractional shortening was decreased and the pulsatility in the ductus venosus blood velocity waveforms was increased.
In conclusion, human fetal myocardial cell damage was associated with a rise in systemic venous pressure, a change in the distribution of cardiac output towards the left ventricle and a rise in right ventricular afterload. Fetuses with retrograde aortic isthmus net blood flow failed to rearrange the distribution of the cardiac output and they had signs of increased left atrial pressure. In addition, right ventricular afterload and pulsatility in the ductus venosus blood velocity waveforms were increased.
|
299 |
The heart in hereditary transthyretin amyloidosis : clinical studies on the impact of amyloid fibril compositionPilebro, Björn January 2017 (has links)
Background Hereditary transthyretin amyloid (ATTRm) amyloidosis is a systemic disease mainly affecting the peripheral nervous system and the heart. The disease is inherited in an autosomal dominant manner with a varying penetrance. It is caused by mutations in the transthyretin (TTR) gene. Today more than 100 disease causing mutations are known. The V30M mutation that is endemic in northern Sweden is the best studied and comprises the majority of the reported disease cases in the world. In ATTRm amyloidosis caused by the V30M mutation two distinct sub populations are seen, one with disease onset early in life and a mainly neuropathic disease and the other with late onset disease and both neuropathic disease and a progressive cardiomyopathy. These phenotypical findings have in Swedish patients been tied to differences in amyloid fibril composition. Generally, patients with early onset disease have amyloid fibrils containing only full length transthyretin (type B) whereas patients with late onset disease have amyloid containing both full length and fragmented transthyretin (type A). Until recently, the only available treatment for the disease has been liver transplantation. Patients with type A fibrils, especially males, have significantly worse survival after liver transplant due to progressive amyloid cardiomyopathy. Furthermore, it appears that type A fibrils may be the most common finding in other mutations. This thesis work aims to in depth investigate the impact amyloid fibril composition has on cardiac manifestations of the disease and on the outcome of available and novel modalities for cardiac amyloid imaging. Methods The four studies included in the thesis were done as part of the on going clinical research at the Swedish centre for transthyretin amyloidosis in Umeå. Patients in whom amyloid fibril composition had been determined were included. Available echocardiographic data were analysed to find predictors for left ventricular hypertrophy and systolic function as measured by strain analysis in a large cohort of 105 patients (paper I). Serial 12-lead electrocardiograms from 98 patients were gathered and retrospectively interpreted and analysed to investigate the impact of amyloid fibril composition and disease progression on frequency and development of ECG abnormalities (paper IV). DPD scintigraphy, cardiac biomarkers, clinical data and echocardiograms were analysed in a cohort of 53 consecutive patients. to assess the impact of amyloid fibril composition on the outcome of DPD scintigraphy and its relationship with cardiac hypertrophy. (paper II). To evaluate the usefulness of positron emission tomography (PET) using the amyloid specific tracer PIB, 10 patients, five with each fibril type, were selected and examined. The patients selected had a similar age of onset and similar echocardiographic findings (paper III). Results Paper I: Type A fibrils, male gender and age were independent factors associated with increased LV thickness. The distribution of amyloid fibril composition did not differ between the sexes, but in patients with type A fibrils, females had lower median cardiac wall thickness (p<0.01and better left ventricular septal strain (p=0.04).The gender differences were not apparent in patients with type B fibrils. Paper II: Ninety-seven per cent of patients with type A fibrils had pathological cardiac DPD uptake compared to none of the patients with type B fibrils. Among patients with normal septal thickness, none of 15 patients with type B fibrils had positive scintigraphy compared with 2 out of 2 with type A fibrils (P<0.01) Cardiac biomarkers, demographic data and cardiac biomarkers were significantly different, but could not differentiate between type A and type B fibrils in individual patients. Paper III: All patients had pathological cardiac PIB retention. In patients with type B fibrils the retention was significantly higher (p<0.01) than in patients with type A fibrils. Based on the selection criteria, no significant differences were seen in various echocardiographic measurements. Paper IV: All patients had a high prevalence of AV-blocks, LAH and anterior infarction pattern. Patients with type A fibrils had significantly more electrocardiographic abnormalities compared to those with type B fibrils, both at an early stage of diseases and at later follow up. Conclusion Type A fibrils are associated with more pronounced cardiac involvement, which appear to be more severe in males than in females. In study II we showed that DPD scintigraphy appears to be a very good tool for non-invasive determination of amyloid fibril composition. Papers III and IV show that patients with type B amyloid have cardiac involvement even without echocardiographic or DPD-scintigraphic evidence of amyloid cardiomyopathy and that ECG abnormalities are common irrespectively of amyloid fibril composition, and increase with time for both groups.
|
300 |
Redução da função sistolica e diastolica do ventriculo esquerdo, estimada pela velocidade do anel mitral, em pacientes hipertensos com e sem hipertrofia ventricular / Longitudinal mitral annulus velocities are reduced in hypertensive subjects with left ventricule hypertrophyBorges, Maria Candida Calzada 23 June 2006 (has links)
Orientador: Kleber Gomes Franchini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T12:07:47Z (GMT). No. of bitstreams: 1
Borges_MariaCandidaCalzada_D.pdf: 3690302 bytes, checksum: 0c73a392de92a2836881cbe3034c49f5 (MD5)
Previous issue date: 2006 / Resumo: Estudos epidemiológicos têm estabelecido uma relação contínua entre a massa do ventrículo esquerdo (VE) e o risco cardiovascular na população geral e na população hipertensa. O pior prognóstico de pacientes hipertensos com aumento na massa do VE tem sido, em parte, atribuído à disfunção do miocárdio, mas permanece desconhecido se os pacientes hipertensos sem hipertrofia do VE (HVE) definida pelos critérios habituais apresentam alterações na função do miocárdio. Os índices ecocardiográficos derivados das dimensões do VE e das velocidades do fluxo mitral aferidas através do Doppler têm provado ser geralmente não específicos e insensíveis para a detecção de alterações discretas da dinâmica ventricular. O Doppler Tecidual (DT) tem demonstrado ser um método eficiente e rápido para avaliar a função do miocárdio. Nos pacientes hipertensos com hipertrofia do VE tem sido descrita redução das velocidades sistólica e diastólica inicial. Entretanto não tem sido relatada investigação da função sistólica do miocárdio do VE através do DT em pacientes hipertensos sem ou com discreta elevação da massa do VE. O presente estudo avalia se, através da velocidade sistólica e diastólica aferidas pelo DT, é possível identificar alterações na contração e relaxamento do miocárdio de indivíduos hipertensos com ou sem hipertrofia ventricular definida pelos valores de corte habituais e com fração de ejeção preservada. Para tanto indivíduos normotensos e hipertensos com ou sem hipertrofia do ventrículo esquerdo (índice de massa do VE [IMVE] > 51g/m2.7) foram avaliados através da ecocardiografia convencional e do DT em 5 segmentos do anel mitral. Os subgrupos incluíram indivíduos normotensos não obesos (n=16; idade 51 ± 9 anos; 11 feminino; pressão arterial sistólica [PAS] 109 ± 11 mmHg; índice de massa corpórea [IMC] 24 ± 2,7 Kg/m2 ; IMVE 32 ± 5.5g/m2.7), hipertensos não obesos sem HVE (n=16; idade 54 ± 12 anos ; 12 femininos; PAS 166 ± 15 mmHg; IMC 25 ± 2,7 g/m2; IMVE 42 ± 5,5 g/m2.7) e hipertensos não obesos com HVE (n=22; idade 56 ± 10 anos; 10 feminino; PAS 181 ± 19 mmHg; IMC 26 ± 2,3 g/m2; IMVE 69 ± 16 g/m2.7). A fração de ejeção foi comparável entre os subgrupos, mas a fração de encurtamento da parede média foi reduzida nos pacientes hipertensos com hipertrofia do VE (¿26%). O tempo de relaxamento isovolumétrico foi aumentado nos pacientes hipertensos com hipertrofia do VE, enquanto a velocidade A do fluxo mitral encontrou-se aumentada em indivíduos hipertensos com e sem hipertrofia do VE. A velocidade sistólica (SM) e diastólica inicial (EM) aferida através do DT ao nível do anel mitral encontraram-se significativamente reduzidas nos indivíduos hipertensos com e sem HVE quando comparadas com as dos indivíduos normotensos. Evidenciou-se correlação positiva entre SM e EM (r=0,68; p<0,0001) e correlação negativa entre essas duas variáveis e o IMVE (SM, r= -0,41; p=0,002; EM, r= -0,56; p<0,0001). Portanto a redução na velocidade sistólica e diastólica ao nível do anel mitral acompanha o aumento da massa do VE em indivíduos hipertensos, iniciando-se em níveis de IMVE que se encontram abaixo dos valores definidos clinicamente como normais / Abstract: Epidemiological studies have established a continuous relationship between the left ventricular (LV) mass and cardiovascular risk in the general and hypertensive population. The poorer prognosis of hypertensive subjects with major increases in LV mass has been, in part, attributed to myocardial dysfunction, but it remains unknown whether hypertensive subjects without clinically defined LV hypertrophy have subtle abnormalities of myocardial function. Echocardiographic indices derived from LV chamber dimensions and Doppler measurements of flow velocities have been proved to be generally nonspecific and insensitive for the detection of minor abnormalities of cardiac relaxation and contraction. Tissue Doppler imaging (TDI) has been advocated as a reliable, rapid, and efficient method to assess myocardial function. In hypertensive patients with LV hypertrophy, TDI mitral annulus systolic and diastolic velocities have been shown to be reduced. However, a comprehensive TDI approach has not been reported in hypertensive subjects without or with minor increases in LV mass. The present study examines whether, by using TDI early systolic and diastolic velocities, one might identify changes in LV myocardial contraction and relaxation in subsets of hypertensive with and without clear-cut, clinically defined LV hypertrophy and normal LV ejection fraction. Normotensive and hypertensive subjects with and without left ventricular (LV) hypertrophy (LV mass index [LVMI] =51 g/m2.7) were examined by conventional echocardiography and tissue Doppler imaging of mitral annulus motion. The subgroups included non obese normotensive subjects (n=16; age 51±9 years; 11 female; systolic blood pressure [SBP] 109±11 mm Hg, body mass index [BMI] 24±2.7 kg/m2; LVMI 32±5.5 g/m2.7), non obese hypertensive subjects without LV hypertrophy (n=16; age 54±12 years; 12 female; SBP 166±15 mm Hg; BMI 25±2.7 kg/m2; LVMI 42_5.5 g/m2.7), and hypertensive subjects with LV hypertrophy (n=22; age 56±10 years; 10 female; SBP 181±19 mm Hg; BMI 26±2.3 kg/m2; LVMI 69±16 g/m2.7). Ejection fraction was comparable among the subgroups, but midwall fractional shortening was reduced in hypertensive subjects with LV hypertrophy (¿26%). Isovolumic relaxation time was increased in subjects with LV hypertrophy, whereas mitral wave A velocity was increased in hypertensive subjects with and without LV hypertrophy. Tissue Doppler imaging mitral annulus systolic (SM) and diastolic (EM) velocities were reduced in subjects with and without LV hypertrophy compared with normotensive subjects. There was a positive correlation between SM and EM (r=0.68; P<0.0001) and negative correlations between these 2 variables and LVMI (SM, r= -0.41; P=0.002; EM, r=-0.56; P<0.0001). Thus, reductions in mitral annulus systolic and diastolic velocities parallel increases in LV mass in hypertensive subjects, beginning at LV mass within the clinically defined normal values / Doutorado / Medicina Experimental / Doutor em Fisiopatologia Medica
|
Page generated in 0.0683 seconds