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Conventional echocardiographic parameters are currently used in determining the timing for surgery in patients with mitral regurgitation. Since brain natriuretic peptide (BNP) rises in response to ventricular muscle stretch, and is to detect early heart failure, we hypothesized that BNP would be activated in patients with regurgitant valvular heart disease and concomitant left ventricular dilatation. Aim/Objectives: We therefore studied the pattern of changes in NT-pro BNP in patients with chronic severe rheumatic mitral regurgitation who were undergoing mitral valve replacement and compared this with the newer modality of tissue Doppler imaging (TDI). Setting: Patients submitted to surgery were prospectively evaluated over 8 months at Inkosi Albert Luthuli Central Hospital, Department of Cardiology. Controls were obtained from the outpatients' follow-up clinic. Methods: Simultaneous quantification of the severity of mitral regurgitation (MR), left ventricular (LV) end systolic volume (ESV), left atrial (LA) volume and Doppler filling ratios (mitral (E)/annulus (Ea)) were performed at baseline in all patients and was repeated at 1-week and at the six-week follow-up visit in surgical patients. Results: Both groups were similar for age and gender and echo-Doppler parameters in all patients preoperatively except LA size (p< 0.01) and volume (p<0.004) which were more elevated in the surgical group. Mean NT-pro BNP levels were markedly elevated preoperatively (262 pmolll) in all surgical cases compared to controls (57 pmol/l; p=0.0001). NT-pro BNP levels increased further at one week post surgery (395 pmol/l) and subsided at the six week follow-up visit (94 pmol/I). These changes were accompanied by significant reduction in LA (p= 0.003) and LV chamber dimensions (EDD = 0.004) with an increase in the ejection fraction from 42% at one week to 52 % at six weeks. Four patients had abnormally elevated NT-pro BNP levels (>53pmol/l) at the 6-week follow-up visit. A ROC curve was constructed for all variables to separate surgical cases from controls. The area under the curve was highest for NT-pro BNP (sensitivity= 96%, specificity 45 %). Conclusion: 1. There was a significant difference in the left atrial chamber size and volume, as well as Em/Ea (TDI) and NT-proBNP levels preoperatively between the two groups. The lack of a significant difference in the LV parameters between surgical and control groups suggest an almost total reliance on symptoms in deciding the timing of surgery which was reflected by markedly elevated NT-pro BNP in all surgical patients. 2. Postoperatively, there was a significant reduction in LA and LV dimensions. 3. The high false positivity rate for NT-pro BNP suggests that the test is most likely reflecting early LV decompensation in the less symptomatic control patients who rightly need surgery. 4. Tissue Doppler indices had similar sensitivity but low specificity compared to NT-proBNP. 5. Serial estimations of NT-pro BNP may prove useful in selecting patients for surgery. / Thesis (M.Med.Sc.)-University of KwaZulu-Natal, 2007.

Made available in DSpace on 2015-04-09T12:28:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-04-08Bitstream added on 2015-04-09T12:48:22Z : No. of bitstreams: 1 000814285.pdf: 1972642 bytes, checksum: 8efc267f7ca1192b3f5cfa61b70cebed (MD5) / A mensuração do volume atrial esquerdo (VAE) indexado a área de superfície corpórea (ASC) é obtido por meio do método biplanar de Simpson via ecocardiografia, e considerado um marcador prognóstico na avaliação da sobrecarga atrial esquerda nas cardiomiopatias e valvulopatias na medicina. Entretanto, nos cães com degeneração mixomatosa da válvula mitral (DMVM), valvulopatia caracterizada pela sobrecarga do átrio esquerdo (AE), a avaliação da sobrecarga atrial é realizada através da obtenção do diâmetro do AE e sua relação com o diâmetro da artéria Aorta (Ao) (AE:Ao), auxiliando na classificação da insuficiência cardíaca congestiva (ICC). Portanto, procurou-se mensurar os valores referentes ao VAE indexados à ASC de cães sadios e portadores da DMVM, utilizando o método biplanar de Simpson. Para isso, foram avaliados 107 cães sadios (controle) e 81 portadores da DMVM classes funcionais Ia, Ib e II da ICC (ISACHC), com o cálculo do VAE nos momentos da diástole (d) e sístole (s) atrial utilizando o método biplanar de Simpson. As imagens apicais quatro (4C) e duas câmaras (2C) foram obtidas por meio da ecocardiografia bidimensional via janela paraesternal esquerda (JPE) e direita (JPD) em todos os cães avaliados. Os valores referentes aos cães sadios foram correlacionados com o peso corporal utilizando o teste linear de Pearson e submetidos ao teste de normalidade estatística. Na comparação dos cães sadios com os portadores da DMVM, bem como entre as classes funcionais de ICC, utilizou-se análise de variância (ANOVA) e o teste de Tukey quando p<0,05. Os resultados demonstraram uma correlação alta e positiva das variáveis VAEd (r>0,77) e VAEs (r>0,73) com o peso corporal nos cães sadios, com posterior indexação dos valores na ASC e aprovação no teste de normalidade. Os valores obtidos utilizando a JPE e a JPD demonstraram diferenças significativas entre as janelas paraesternais. Já os cães ... / The measurement of left atrial volume (LAV) indexed to body surface area ( ASC ) is obtained by the biplane Simpson method via echocardiography , and considered a prognostic marker in assessing left atrial cardiomyopathy and valvular heart disease in medicine . However , in dogs with myxomatous mitral valve (MMVD), valvular heart disease characterized by an overload of the left atrium (LA) , the assessment of atrial enlargement is accomplished by obtaining the LA diameter and its relation to the diameter of the aorta (Ao ) (LA:Ao) , assisting in the classification of congestive heart failure (CHF) . Therefore, we sought to measure the values for LAV indexed to ASC of healthy dogs and MMVD carriers using the biplane Simpson method. . Thus, 107 healthy dogs (control) and 81 patients with functional MMVD classes Ia, Ib and II of the CCI (ISACH) were evaluated by calculating the time of VAE in diastole (d) and systole (s) fibrillation using biplane Simpson’s method. The framework (4C) and apical two-chamber images (2C) were obtained by two-dimensional echocardiography via left parasternal (JPE) in all dogs evaluated. The values for the healthy dogs were correlated with body weight using the Linear Test Pearson and submitted to statistical normality test. In comparison with healthy carriers of MMVD dogs, as well as between functional classes of ICC, we used analysis of variance (ANOVA) and Tukey's test at p<0.05. The results showed high positive correlation between LVAd (r>0.77) and LVAs (r > 0.73) variables with body weight in healthy dogs, with subsequent indexation of amounts on ASC and passing the normality test correlation. The values obtained using the JPE and JPD showed significant differences between the parasternal windows. The dogs with MMVD present significant differences (p<0.01) between functional classes Ib and II to the control group in LVAd/ASC ...

Orientador: Aparecido Antonio Camacho / Banca: Mirela Tinucci Costa / Banca: Tatiana Champion / Banca: Fabio Nelson Gava / Banca: Marlos Gonçalves Souza / Resumo: A insuficiência cardíaca congestiva (ICC) é uma síndrome que leva ao inadequado suprimento sanguíneo tecidual por disfunção do coração, e é tratada com a administração de furosemida em bolus intermitentes (BI). Entretanto, estudos em seres humanos com ICC demonstraram que a furosemida em taxa infusão contínua (TIC) apresenta maior eficácia e segurança em relação à administração em BI. Portanto, o objetivo deste estudo foi comparar a eficácia do diurético furosemida em TIC e BI em cães com degeneração mixomatosa valvar mitral. Para este fim, o estudo incluiu 20 cães, entre 8 e 12 anos, com peso entre 8 e 15 kg, e ICC classes Ia, Ib e II - ISACHC, e o grupo controle. Para o tratamento TIC, os cães receberam 0.66mg/kg IV furosemida como uma dose de carga seguida de 0.66mg/kg/h durante 8 horas. No tratamento BI os cães receberam 3 mg/kg IV furosemida na 0 e 4 horas. Os cães foram submetidos a tratamento por TIC e 15 dias mais tarde, os mesmos cães foram submetidos a tratamento por BI. Para ambos os tratamentos, foi administrado o mesmo volume de fluido e a produção de urina foi quantificada a cada hora. A ingestão hídrica, densidade urinária, pH urinário foram avaliados por hora. As variáveis sanguíneas, hematócrito (Ht), hemoglobina (Hb), creatinina (creat), ureia, proteína total (PT), albumina (alb) e os eletrólitos sódio (Na), potássio (K), magnésio (Mg), cálcio (Ca) e fosforo (P) foram avaliados a cada 2 horas. O peso e as variáveis ecocardiográficas foram avaliados antes e depois do tratamento. A produção urinaria por hora (mL/kg/h) e total (mL/kg/8h) foi superior no tratamento TIC em todos os animais (p<0,05). Os parâmetros ingestão hídrica, densidade urinária, diferença de pH urinário, diferença de peso, Ht, Hb, ureia, creat e fósforo junto com as diferenças das variáveis ecocardiográficas não apresentaram diferenças significativas entre os tratamentos (p>0,05). A furosemida... / Abstract: Congestive heart failure (CHF) is a syndrome that leads to inadequate blood supply to the tissue due to heart dysfunction and is treated with furosemide in intermittent bolus (BI). However, studies in humans with CHF showed that furosemide continuous rate infusion (CRI) showed better efficacy and safety for the administration in BI. Therefore, the aim of this study was to compare the effectiveness of the diuretic furosemide in CRI and BI in dogs with mitral valve myxomatous degeneration. To this end, the study included 20 dogs between 8 and 12 years old, weighing between 8 and 15 kg, and ICC classes Ia, Ib and II - ISACHC, and the control group. CRI for the treatment, the dogs received 0.66mg/kg IV furosemide as a loading dose followed by 0.66mg/kg/h for 8 hours. BI treatment the dogs received 3 mg / kg IV furosemide at 0 and 4 hours. The dogs were treated by CRI and 15 days later, the same dogs were treated by BI. For both treatments, the same volume of fluid and urine production was quantitated was administered hourly. The water intake, urine specific gravity, urine pH were evaluated per hour. The variable blood, hematocrit (Hct), hemoglobin (Hb), creatinine (creat), urea, total protein (TP), albumin (ALB) and electrolytes sodium (Na), potassium (K), magnesium (Mg), calcium (Ca) and phosphorus (P) were evaluated every two hours. The weight and Doppler echocardiographic variables were evaluated before and after treatment. The urinary output per hour (mL/kg/h) and total (mL/kg/8h) was higher in the treatment CRI in the control group and CHF class II (p <0.05). The water intake, urine specific gravity, urinary pH difference, weight loss, Ht, Hb, urea, creat and phosphorus parameters along with the differences in Doppler echocardiographic variables were not significantly different between treatments (p> 0.05). The furosemide continuous infusion rate has increased urine output in dogs with MMVD functional classes Ia, Ib, II and ... / Doutor