Submitted by Mariana Moraes Contti (mmcontti@gmail.com) on 2019-01-31T12:54:19Z No. of bitstreams: 1 TESE HOMOLOG.pdf: 3705229 bytes, checksum: 788c829d039c6d6dc4dd78578b4db8ae (MD5) / Approved for entry into archive by Luciana Pizzani null (luciana@btu.unesp.br) on 2019-01-31T18:08:57Z (GMT) No. of bitstreams: 1 contti_mm_dr_bot.pdf: 3705229 bytes, checksum: 788c829d039c6d6dc4dd78578b4db8ae (MD5) / Made available in DSpace on 2019-01-31T18:08:57Z (GMT). No. of bitstreams: 1 contti_mm_dr_bot.pdf: 3705229 bytes, checksum: 788c829d039c6d6dc4dd78578b4db8ae (MD5) Previous issue date: 2018-12-03 / RESUMO: A ressonância magnética cardíaca (RMC), usando o T1 nativo, é considerado método não invasivo para avaliar fibrose miocárdica sem necessidade de usar contraste paramagnético. Até o momento não há dados a respeito do T1 nativo após o transplante renal. O objetivo primário deste estudo foi avaliar mudanças no T1 nativo do miocárdio, seis meses após o transplante renal. Foram analisados prospectivamente, 44 pacientes transplantados renais, os quais foram submetidos a 2 exames de RMC (3T): o 1º nos 10 dias inicias do transplante, e o 2º realizado seis meses após. O tempo do T1 nativo foi medido na região médio- septal e diminuiu significativamente de 1.331 ±52 ms (inicial) para 1.298±42 ms, seis meses após o transplante (p = 0,001). Os pacientes foram divididos em 2 grupos segundo o algoritmo de cluster: no cluster-1 (n=30), a massa do ventrículo esquerdo indexada (MVEi) foi menor, e não foi encontrado nenhum paciente portador de diabetes. No cluster-2 (n=14), a MVEi foi maior, e 100% dos pacientes eram diabéticos. A diminuição do T1 nativo foi significativa apenas nos pacientes do cluster-1 (p = 0,001). Concluindo, o tempo de T1 nativo do miocárdio diminuiu significativamente seis meses após o transplante renal, fato que pode estar associado com regressão da fibrose reativa. O grupo de pacientes que apresentou maior prevalência de diabetes e maior MVEi não alcançou diminuição do T1. ABSTRACT: The measurement of native T1 through cardiac magnetic resonance (CMR) is a noninvasive method of assessing myocardial fibrosis without gadolinium contrast. No studies so far have evaluated native T1 after renal transplantation. The primary aim of the current study is to assess changes in the myocardium native T1 six months after renal transplantation. We prospectively evaluated 44 renal transplant patients who were undergoing two 3-Tesla CMR exams: baseline at the beginning of transplantation and the second after six months. The native T1 time was measured in the midseptal region and decreased significantly from 1,331±52 ms at the baseline to 1,298±42 ms 6 months after transplantation (p = 0.001). The patients were split into two groups through a two-step cluster algorithm: in cluster-1 (n = 30) the left ventricular mass index (LVMi) was lower, and no patient with diabetes was found. In cluster-2 (n = 14) the LVMi and diabetes prevalence were higher. Decrease in native T1 values was significant only in the patients in cluster-1 (p = 0.001). In conclusion, the native myocardial T1 time decreased significantly six months after renal transplant, which may be associated with the regression of the reactive fibrosis. The patients with greater baseline LVMi and the diabetic group did not reach a significant decrease in T1.

Orientador: Luis Gustavo Modelli de Andrade / Resumo: RESUMO: A ressonância magnética cardíaca (RMC), usando o T1 nativo, é considerado método não invasivo para avaliar fibrose miocárdica sem necessidade de usar contraste paramagnético. Até o momento não há dados a respeito do T1 nativo após o transplante renal. O objetivo primário deste estudo foi avaliar mudanças no T1 nativo do miocárdio, seis meses após o transplante renal. Foram analisados prospectivamente, 44 pacientes transplantados renais, os quais foram submetidos a 2 exames de RMC (3T): o 1º nos 10 dias inicias do transplante, e o 2º realizado seis meses após. O tempo do T1 nativo foi medido na região médio- septal e diminuiu significativamente de 1.331 ±52 ms (inicial) para 1.298±42 ms, seis meses após o transplante (p = 0,001). Os pacientes foram divididos em 2 grupos segundo o algoritmo de cluster: no cluster-1 (n=30), a massa do ventrículo esquerdo indexada (MVEi) foi menor, e não foi encontrado nenhum paciente portador de diabetes. No cluster-2 (n=14), a MVEi foi maior, e 100% dos pacientes eram diabéticos. A diminuição do T1 nativo foi significativa apenas nos pacientes do cluster-1 (p = 0,001). Concluindo, o tempo de T1 nativo do miocárdio diminuiu significativamente seis meses após o transplante renal, fato que pode estar associado com regressão da fibrose reativa. O grupo de pacientes que apresentou maior prevalência de diabetes e maior MVEi não alcançou diminuição do T1. ABSTRACT: The measurement of native T1 through cardiac magnetic resonance (CMR) is a noni... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

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Background: This study aimed to evaluate the incremental prognostic value of infarct size, microvascular obstruction (MO), myocardial salvage index (MSI), and left ventricular ejection fraction (LV-EFCMR) assessed by cardiac magnetic resonance imaging (CMR) in comparison to traditional outcome markers in patients with ST-elevation myocardial infarction (STEMI) reperfused by primary percutaneous intervention (PCI). Methods: STEMI patients reperfused by primary PCI (n = 278) within 12 hours after symptom onset underwent CMR three days after the index event (interquartile range [IQR] two to four). Infarct size and MO were measured 15 minutes after gadolinium injection. T2-weighted and contrast-enhanced CMR were used to calculate MSI. In addition, traditional outcome markers such as ST-segment resolution, pre- and post-PCI Thrombolysis In Myocardial Infarction (TIMI)-flow, maximum level of creatine kinase-MB, TIMI-risk score, and left ventricular ejection fraction assessed by echocardiography were determined in all patients. Clinical follow-up was conducted after 19 months (IQR 10 to 27). The primary endpoint was defined as a composite of death, myocardial reinfarction, and congestive heart failure (MACE). Results: In multivariable Cox regression analysis, adjusting for all traditional outcome parameters significantly associated with the primary endpoint in univariable analysis, MSI was identified as an independent predictor for the occurrence of MACE (Hazard ratio 0.94, 95% CI 0.92 to 0.96, P <0.001). Further, C-statistics comparing a model including only traditional outcome markers to a model including CMR parameters on top of traditional outcome markers revealed an incremental prognostic value of CMR parameters (0.74 versus 0.94, P <0.001). Conclusions: CMR parameters such as infarct size, MO, MSI, and LV-EFCMR add incremental prognostic value above traditional outcome markers alone in acute reperfused STEMI.

Obesity is a major epidemic and is increasing in prevalence worldwide. The health problems and consequences of obesity include cardiovascular disease (CVD) risk factors, such as hypertension, hyperlipidemia, glucose intolerance and diabetes mellitus. Each of these abnormalities directly promotes atherosclerosis. More recently, visceral obesity has been shown to be independently associated with abnormalities of both the ventricular and vascular structure and function. The mechanisms by which they occur remain incompletely defined. Cardiovascular magnetic resonance imaging (CMR) offers several advantages for evaluation of cardiac structure and function in the obese. The high accuracy and reproducibility of the technique allows for detection of very small changes in ventricular volumes, mass, ejection fraction, and cardiac output with a relatively small sample size, as compared with echocardiography. In this thesis we investigated whether cardiovascular magnetic resonance imaging can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. Obesity is associated with myocardial and vascular function, the extent of reversibility of these abnormalities with rapid acute weight loss remains uncertain. Therefore the first aim of the study was to (i) determine the relationship between obesity and left ventricular structure and function using magnetic resonance imaging, and (ii) the acute effects of rapid diet-induced weight loss on cardiac and vascular function in normal obese and obese diabetic men. Erectile dysfunction is related to cardiovascular risk factors such as obesity by an impairment of endothelial function. Therefore, symptoms of erectile dysfunction are probably to precede cardiovascular disease and events. The second aim of this study was to (i) determine the relationship between obesity and erectile function (EF), sexual desire (SD), lower urinary tract symptoms (LUTS) and quality of life (QOL) measures in obese males, and (ii) determine the effects of rapid diet-induced weight loss on EF, SD, LUTS and QOL measures in normal obese and obese diabetic men. In this group of men, obesity was associated with mild/moderate erectile dysfunction, and significant LUTS, which together with sexual desire improved following rapid diet induced weight loss, but was not directly related to the amount of weight loss or changes in measured metabolic state. Pericardial adipose tissue (PAT) covers 80% of the heart and constitutes 20% of its weight. PAT mass is related to the amount of abdominal fat and the risk of coronary atherosclerosis. Epicardial fat mass may be a sensitive indicator of cardiovascular risk. The third aim of this study was to (i) determine the relationship between obesity and PAT volume and (ii) effectively evaluate the impact of caloric restriction and associated weight reduction on epicardical fat volume via cardiac magnetic resonance imaging (CMR). This is the first study to show a reduction in PAT volume is associated with caloric restriction. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352389 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009

Obesity is a major epidemic and is increasing in prevalence worldwide. The health problems and consequences of obesity include cardiovascular disease (CVD) risk factors, such as hypertension, hyperlipidemia, glucose intolerance and diabetes mellitus. Each of these abnormalities directly promotes atherosclerosis. More recently, visceral obesity has been shown to be independently associated with abnormalities of both the ventricular and vascular structure and function. The mechanisms by which they occur remain incompletely defined. Cardiovascular magnetic resonance imaging (CMR) offers several advantages for evaluation of cardiac structure and function in the obese. The high accuracy and reproducibility of the technique allows for detection of very small changes in ventricular volumes, mass, ejection fraction, and cardiac output with a relatively small sample size, as compared with echocardiography. In this thesis we investigated whether cardiovascular magnetic resonance imaging can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. Obesity is associated with myocardial and vascular function, the extent of reversibility of these abnormalities with rapid acute weight loss remains uncertain. Therefore the first aim of the study was to (i) determine the relationship between obesity and left ventricular structure and function using magnetic resonance imaging, and (ii) the acute effects of rapid diet-induced weight loss on cardiac and vascular function in normal obese and obese diabetic men. Erectile dysfunction is related to cardiovascular risk factors such as obesity by an impairment of endothelial function. Therefore, symptoms of erectile dysfunction are probably to precede cardiovascular disease and events. The second aim of this study was to (i) determine the relationship between obesity and erectile function (EF), sexual desire (SD), lower urinary tract symptoms (LUTS) and quality of life (QOL) measures in obese males, and (ii) determine the effects of rapid diet-induced weight loss on EF, SD, LUTS and QOL measures in normal obese and obese diabetic men. In this group of men, obesity was associated with mild/moderate erectile dysfunction, and significant LUTS, which together with sexual desire improved following rapid diet induced weight loss, but was not directly related to the amount of weight loss or changes in measured metabolic state. Pericardial adipose tissue (PAT) covers 80% of the heart and constitutes 20% of its weight. PAT mass is related to the amount of abdominal fat and the risk of coronary atherosclerosis. Epicardial fat mass may be a sensitive indicator of cardiovascular risk. The third aim of this study was to (i) determine the relationship between obesity and PAT volume and (ii) effectively evaluate the impact of caloric restriction and associated weight reduction on epicardical fat volume via cardiac magnetic resonance imaging (CMR). This is the first study to show a reduction in PAT volume is associated with caloric restriction. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352389 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009

Introdução: A miocardiopatia chagásica (MC) apresenta pior prognóstico que as etiologias isquêmica e não isquêmica de miocardiopatia, e acarreta alto custo. A fibrose miocárdica (FM) detectada pela Ressonância Magnética Cardíaca (RMC) mostrou-se um fator preditor independente de risco aumentado em diversas etiologias de insuficiência cardíaca. Na MC, a FM foi associada com marcadores conhecidos de pior prognóstico, como a disfunção ventricular esquerda e arritmia ventricular. Nossa hipótese é que a FM é um fator preditor independente de pior prognóstico na MC. Objetivos: Buscamos estabelecer o valor prognóstico da FM detectada pela RMC na predição de uma combinação de desfechos duros ou do desfecho secundário mortalidade por todas as causas. Adicionalmente, avaliamos se o valor prognóstico da FM é independente do Escore de Rassi. Métodos: Pacientes com MC foram incluídos retrospectivamente após a realização da RMC, que avaliou volumes e função cardíacos, além de quantificar a FM. Dados clínicos, de imagem e seguimento foram registrados, e o desfecho primário foi a combinação de mortalidade por todas as causas, transplante cardíaco, terapia antitaquicardia ou choque apropriado pelo cardiodesfibrilador implantável e morte súbita cardíaca abortada; o desfecho secundário foi mortalidade por todas as causas. Resultados: Foram incluídos no estudo130 pacientes, a maioria de mulher (53,9%), com idade média de 53,6±11,5 anos. A maioria dos pacientes (68,4%) não tinha sintomas de insuficiência cardíaca, apesar da dilatação ventricular esquerda (54%) e alterações da contratilidade (65,9%) serem comuns. A RMC mostrou dilatação do ventrículo esquerdo (volume diastólico final indexado médio de 118,6±50,5ml/m²) e disfunção sistólica (fração de ejeção média de 43,2±16,3%) e a FM foi identificada em 76,1%, massa média de 15,2±16,5g. Ao longo do seguimento médio de 6,8 anos, 58 (44,6%) pacientes atingiram o desfecho combinado e 45 (34,6%) faleceram. A MF associou-se ao desfecho primário como variável contínua (Razão de risco (RR) ajustada 1,031 (Intervalo de Confiança (IC) 95% 1,013-1,049; p=0.001) e nos pacientes com FM extensa ( >= 12,3g) (RR ajustado 2,107 (IC 95% 1,111-3,994I; p=0,022)) de forma independente ao Escore de Rassi. A FM expressa como variável contínua também se associou à morte por todas as causas (RRajustado1,028 (IC 95% 1,005-1,051; p=0,017)) de forma independente do Escore de Rassi, exceto quando analisada como variável categórica. Conclusões: A fibrose miocárdica é um preditor independente de pior prognóstico na miocardiopatia chagásica. Nossos dados apoiam o uso da RMC para estratificar melhor o risco nessa população e, possivelmente, guiar o tratamento / Background: Chagas cardiomyopathy (CC) portends worse prognosis than ischemic and other non-ischemic cardiomyopathies and carries a high economic burden. Myocardial fibrosis (MF) detected by cardiac magnetic resonance (CMR) has been demonstrated as an independent predictor of increased risk in several etiologies of heart failure. In CC, MF has been associated with know risk factors of poor outcome, such as left ventricular dysfunction and ventricular arrhythmia. We hypothesized that MF is an independent predictor of worse prognosis in CC. Objectives: we sought to determine the prognostic value of MF detected by CMR in predicting a combined endpoint of hard events or the secondary outcome of all-cause mortality. In addition, we evaluated if the prognostic value of MF is independent of the Rassi risk score. Methods: patients with CC were retrospectively followed after CMR evaluation of cardiac volumes, function and MF quantification. Clinical, imaging and follow-up data were recorded and the primary outcome was a combination of all-cause mortality, heart transplantation, anti-tachycardia pacing or appropriate shock from an implantable cardiac defibrillator and aborted sudden cardiac death; the secondary outcome was all-cause death. Results: 130 patients were included in the study, with a majority of females (53.9%) and a mean age of 53.6±11.5 years. Most patients (68.4%) had no symptoms of heart failure, even though left ventricular dilatation (54%) and wall-motion abnormalities (65.9%) were common. On CMR, left ventricular dilatation (mean end-diastolic volume index 118.6±50.5ml/m²) and dysfunction (mean ejection fraction 43.2±16.3%) were observed and MF was found in 76.1%, with a mean mass of 15.2±16.5g. Over a mean follow-up of > 6.2 years, 58 (44.6%) patients reached the combined endpoint and 45 (34.6%) patients died. Myocardial fibrosis mass was associated with the primary outcome both as continuous variable (adjusted HR 1.031 (1.013-1.049 95% CI; p=0.001) and in patients with extensive MF ( >= 12.3g) (adjusted HR 2.107 (1.111-3.994 95% CI; p=0.022), independently from the Rassi Score. Myocardial fibrosis mass expressed as a continuous variable was also associated with all-cause death (adjusted HR 1.028 (1.005-1.051 95% CI; p=0.017) independently from the Rassi Score, but not when analyzed as a categorical variable. Conclusions: Myocardial fibrosis is an independent predictor of adverse outcome in Chagas cardiomyopathy. Our data support the use of CMR in better stratifying risk in this population and possibly guiding therapy

Beta-talassemia é uma das doenças genéticas mais comuns no mundo, com graus variados de anemia crônica, tratados por transfusões sanguíneas rotineiras nos casos mais graves. A sobrecarga de ferro acentuada a que esses pacientes são submetidos é a principal responsável pela morbimortalidade, sendo o acúmulo de ferro no miocárdio e a doença cardíaca disso decorrente, a principal causa de morte nessa população. A ressonância magnética cardíaca (RMC) é ferramenta central no acompanhamento desses pacientes, utilizando-se da técnica T2*, capaz de determinar a presença e grau da deposição de ferro no miocárdio, modificando o tratamento da terapia quelante de ferro (TQF). Além disso, outros parâmetros volumétricos e funcionais obtidos no exame de RMC podem estar alterados nesses pacientes. Até a atualidade, inexistem estudos nacionais descrevendo uma população de pacientes beta-talassêmicos pelos parâmetros da RMC. Objetivos: 1. Caracterizar a partir dos diversos parâmetros dos exames de RMC, a população dos pacientes talassêmicos acompanhados no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto. 2. Avaliar o impacto dos diversos parâmetros da RMC com informações clinicas como mudança terapêutica, ocorrência de insuficiência cardíaca e óbito. Métodos: foram avaliados 44 pacientes com diagnóstico de beta-talassemia em seguimento no serviço de hematologia, para os quais foram solicitados exames de RMC na rotina clínica. Os exames incluíram sequências cine SSFP (steady state free precession) nos diversos planos cardíacos, incluindo uma sequência do eixo curto de ambos os ventrículos, esta utilizada para as medidas de volumes e função ventriculares. A sequência T2* utilizada foi gradiente eco com pré-pulso de saturação do sangue, com aquisição de 9 ecos consecutivos em apenas uma apneia. Sequência semelhante foi obtida para cálculo do T2* hepático. Foi feita revisão dos prontuários dos pacientes para avaliação dos dados clínicos. Resultados: 44 pacientes foram avaliados (25 do sexo masculino 56,8 %), com idade de 23,1±10,3 anos e diagnóstico de beta-talassemia maior em 30 casos (68,2 %) e talassemia intermedia em 14 casos (31,8 %). Foram descritos os volumes, massa e função para ambos os ventrículos, bem como a distribuição da medida do T2* miocárdico. Não foram observadas diferenças desses parâmetros entre os diferentes grupos de impregnação miocárdica pelo T2*. O seguimento médio do estudo foi de 4,0 (±1,1) anos com 4,7 (±1,6) exames por paciente. Foram identificados cinco pacientes com doença cardíaca e dois óbitos. Esses pacientes apresentaram redução significativa do T2* miocárdico, da fração de ejeção do ventrículo direito (VD), massa ventricular direita e esquerda e do volume sistólico final do VD, quando comparados aos indivíduos sem acometimento cardíaco reportado. Conclusão: Caracterizou-se a população de pacientes beta-talassêmicos acompanhados nesta instituição, em relação aos diversos parâmetros da RMC, salientando-se o impacto da introdução do método na mudança terapêutica. A medida do T2* miocárdico está correlacionada ao desenvolvimento de cardiopatia e pior evolução clínica, incluindo óbito. Acometimento do VD pode ser indicador precoce da impregnação miocárdica. / Beta-thalassemia is one of the most common genetic disorders worldwide, with different degrees of chronic anemia, treated with routine blood transfusions in severe cases. Morbidity and mortality is mainly related to the chronic iron overload and iron burden these patients endure. Myocardial iron overload and the development of cardiac disease remain the main cause of death for this population. Cardiac magnetic resonance (CMR) plays a central role in patient management, utilizing T2* sequences, which allows for detection and quantification of myocardial iron deposits, thus prompting changes in iron chelation therapy (ICT). Besides, there are other significant CMR volumetric and functional parameters to present abnormalities in these patients. To the present date, no national data has been published, describing a beta-thalassemia patient population from the standpoint of CMR parameters. Objectives: 1. To characterize, from the different CMR parameters, the beta-thalassemia patient population followed at a Brazilian tertiary hospital. 2. To evaluate the impact of these different CMR parameters, in relation to clinical data, such as therapeutic change, cardiac disease and death. Methods: 44 beta-thalassemia patients followed by the hematology service of this institution were evaluated, to whom CMR exams were performed in routine clinical practice. CMR exams included SSFP (steady state free precession) cine images through the different cardiac planes, including a short axis stack through both ventricles, used to calculate ventricular volumes and function. A gradient echo sequence with a dark blood pre-pulse saturation was used to calculate myocardial T2* values, with 9 consecutive echo times acquisition in one breath hold. A similar sequence was used to determine liver T2* values. Medical records were reviewed for clinical data. Results: 44 patients were evaluated (25 males, 56.8 %), with a mean age of 23,1 (±10,3) years, and diagnosis of betathalassemia major in 30 patients (68,2 %) and beta-thalassemia intermedia in 14 (31,8 %). Ventricular volumes, mass and function were described, as well as myocardial T2* distribution. There were no statistical difference observed among the different CMR parameters and the myocardial T2* degrees. Mean follow up was 4,0 (±1,1) years, with 4,7 (±1,6) exams per patient. Five patients with cardiac disease were identified with two deaths during observation. These patients showed a significantly reduced myocardial T2* and RVEF, and an elevated ventricular mass, for both ventricles, and final systolic right ventricular volume, when compared to patients without cardiac disease. Conclusion: A betathalassemia patient population was characterized through the different CMR parameters, highlighting the impact of CMR introduction to treatment decision. Myocardial T2* is related to cardiac disease development, clinical worsening and death. Right ventricular functional worsening could be an early sign of myocardial iron involvement.

Introdução: A história natural da insuficiência mitral associa-se a décadas de remodelação ventricular esquerda com fibrose intersticial. A fronteira entre o processo adaptativo e a miocardiopatia dilatada demanda avaliação clínico-histológica. Atualmente, sabe-se que o melhor método empregado para quantificar as alterações decorrentes do remodelamento que acomete o ventrículo esquerdo é a biópsia miocárdica, que analisa a doença, somente após a cirurgia ou no post mortem. O presente estudo visa avaliar a fibrose miocárdica associada à insuficiência mitral crônica, através de estudo pela Ressonância Magnética, de maneira não invasiva, precoce e rápida. Objetivos: Avaliar a capacidade e a aplicabilidade da ressonância magnética cardíaca de detectar a fibrose miocárdica na insuficiência mitral crônica importante, tendo como referência a biópsia miocárdica. Métodos: Foram selecionados 52 pacientes portadores de IM crônica pura ou associada a estenose mitral leve, com PVM e DR, e com indicação cirúrgica. Todos os pacientes foram reavaliados pelo EcoDopplercardiograma e realizaram ressonância magnética cardíaca para avaliação da função ventricular, volumes e índice de massa ventricular esquerda, através da cine-ressonância e pela técnica do realce tardio miocárdico, com injeção de 0,2 mmol/kg de contraste gadolínio para a detecção de FM, sendo submetidos a cirurgia de plástica ou troca de válvula mitral com bióspsias miocárdicas, retiradas de locais padrão, na parede lateral do ventrículo esquerdo. Todas foram coradas pela técnica do hematoxilinaeosina, e as positivas para FM, confirmadas pelo corante picrossirius, que cora colágeno, e quantificadas pelo aparelho do quantimet. Resultados: Os pacientes foram divididos em quatro grupos, conforme a RM e a biópsia. A RM diagnosticou FM em 18 pacientes, concordantes com a BM (RMC/BM +). A RM foi negativa para FM em 33 pacientes, sendo 28 concordantes com a BM (RMC/BM -). Observou-se discordância de RM com a BM, em 7 casos falsos negativos (RMC-/BM +). A sensibilidade da RMC à fibrose foi de 72%, especificidade de 100%, e acurácia de 86,3%. Nos grupos distintos estudados, a sensibilidade, especificidade e acurácia foram de 64,7%, 100% e 82,4%, respectivamente, na PVM, e de 97,5%, 100% e 92,9%, respectivamente, na DR. O índice Kappa foi de 0,724 (p<0,001) para o grupo total; 0,665 (p<0,001) para PVM e 0,857(p<0,001) na DR. VDF, VSF e IMVE tiveram correlação positiva e significativa com a porcentagem de fibrose, sendo que, quanto maiores esses valores, maior a porcentagem de fibrose. Conclusão: RMC teve boa concordância com a BM, em relação aos achados de FM / Introduction: The natural history of mitral insufficiency (MI) is associated to decades of left ventricular remodelation with intersticial fibrosis. The frontier between adaptative process and dilatade miocardiopaty needs clinic and histologic evaluation. Now a days , we know that the best method to quantify the alterations of remodelation in left ventricule is myocardial biopsies which analyses the illness only after surgery or post morten. This actual study aims to evaluate myocardial fibrosis associated with cronic MI, through the study with magnetic resonance (MR), in a not invasive, early and quickly way. Objectives: Evaluate capacity and applicability of the magnetic resonance in detection of myocardial fibrosis in chronic important mitral insufficiency in reference with myocardial biopsis. Methods: It was selected 52 patients with pure chronic MI or associated with mild mitral stenosis, with cirurgical indication. All of the patients were reevaluated by EcoDopplercardiogram and it was done cardiac MR to evaluate ventricular function, volumes and left ventricular mass rate through MR cine and myocardial late realce techinique with 0,2 mmol/Kg with gadoline contrast and myocardial fibrosis (MF) detection and being undergone plastic or mitral valvular changes surgery with myocardial biopsis (MB) were taken from the left ventricular lateral wall. All of them were colored with hematoxilin eosine and the positives were confirmated with picrossirius and quantified with quantimet device. Results: Patients were divided in four groups according to MR and biopsies. MR diagnosticated MF in 18 patients agreed with MB (MR / MB +). MR was negative for MF in 33 patients where 28 agreed with MB (MR / MB -). We observated discordance with MR and MB in 7 cases false negatives (MR- /MB+). The sensibility of MR to fibrosis was 72%, specificity was 100% and acurace was 86,3%. In the distinct groups studied, we see sensibility, specifity and acure were 64,7%, 100 % and 82,4% respectivity in PVM and 97,5%, 100% and 92,9% respectivity in reumathic disease. The Kappa indice is 0,714 (p<0,001) for the total group; 0,665 (p<0,001) for PMV and 0,857 (p<0,001) in RD. There is a positive correlation and significative between fibroses percentage with VDF, VSF, IMVE of the MR. So the higher the values, higher the fibrosis percentage. Conclusion: MR had a good concordance with MB in relation to found the MF in IMC

In the present study, we sought to investigate the agreement between late gadolinium enhancement (LGE) in cardiovascular magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischemic dilated cardiomyopathy (NIDCM) and how it relates with the procedural outcome after catheter ablation of ventricular arrhythmias (VA). We identified 50 patients with NIDCM who underwent CMR and ablation for VA. LGE was detected in 16 patients (32%), mostly in those presenting with sustained VT (15 patients). Low-voltage areas (<1.5 mV) were observed in 23 patients (46%), in 7 patients (14%) without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 mV and 5 mV for bipolar and unipolar maps, respectively. Most VT exits were found in areas with LGE (12 out of 16 patients). VT exits were found in segments without LGE in 2 patients with unsuccessful ablation as well as in 2 patients with successful ablation, P=0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12.2 ± 5.8% vs. 6.9 ± 3.4%; P=0.049. Myocardial heterogeneity provides the electrophysiological substrate of ventricular arrhythmias in patients with myocardial infarction. Fibrosis and reduction in the number of gap junctions of surviving myocytes allow the occurrence of re-entry (23). However, the relationship between fibrosis and VA is complex and involves not only fixed anatomical barriers but also functional blocks caused by differences in the fiber orientation, myocardial thickness mismatch or connexin downregulation (24-26). Studies involving EAM in patients with scar-related VT demonstrated that homogenization of the low-voltage areas with elimination of the signals showing abnormal amplitude and fractionation was associated with improved acute and long-term success rates (27). On the other hand, animal studies showed that CMR can be useful to characterize LV fibrosis. Moreover, the amount of LGE has been associated with inducibility of VT and is considered a powerful and independent predictor of adverse prognosis, especially in myocardial infarction patients (28-29). In contrast to ischemic cardiomyopathy, LGE is infrequently found in patients with NIDCM. A previous study of 399 patients with NIDCM demonstrated that LGE was detected in approximately one-fourth of the patients and was associated with a 9-fold increase of risk for SCD (30). In accordance with these data, we observed LGE in approximately one third of the patients, and most of them had a history of spontaneous sustained VT. In contrast to the VT patients who have frequently LGE, all patients with ventricular premature beats but without any sustained VT did not show any evidence of LGE in CMR. These observations support the general understanding that the presence of LGE identifies more advanced cardiomyopathy as well as a higher risk for more malignant ventricular arrhythmias. Although myocardial fibrosis is associated with a higher likelihood for VT occurrence, the absence of LGE in CMR does not completely eliminate the risk for VT. Some patients had sustained ventricular arrhythmias even without detectable scar in CMR, which suggests a poorer negative predictive value for the LGE. Although CMR imaging is currently considered the reference standard for the detection of LV scar, it has a limited spatial resolution in vivo. Therefore, minute scars as well as diffuse fibrosis that can still trigger VA may remain undetected. The alternative approach to detect myocardial scar is to characterize the electrical properties of the myocardium by using bipolar EAM in order to find low-voltage areas and late potentials that are markers of abnormal tissue. However, abnormal fragmentation and amplitudes below 1,5 mV are less frequently found in NIDCM in comparison to post-myocardial infarction patients. These findings illustrate the downsides of the EAM in NIDCM. Moreover, numerous animal and clinical studies underlined other technical drawbacks of the EAM that can influence the size and the characteristics of the low-voltage areas such as mapping electrode size and spacing, the angle of contact with the underlying tissue, wave-front direction (31-33). Recently, Betensky and al. analyzed the agreement between CMR and EAM in patients with NIDCM and found a significant discordance between both approaches in 36% of the patients. Using lower signal intensity threshold of 2 standard deviations they increased the CMR-EAM agreement up to almost 90% (34). In contrast to Betensky, who used a simplified approach analyzing only the septal to lateral disagreement, we choose to perform more precise analysis using the 17 segments AHA model of the LV. We found 23 out of 50 patients with low-voltage areas and 15 (71.4%) of them had sustained VT. Moreover only 16 (32%) patients with low-voltage had also LGE in the CMR. In our study the basal inferolateral, inferior and infero-septal segments were most frequently affected by LGE in contrast to the basal anterior and anteroseptal segments affected in the EAM. However, in the LGE positive patients, the best pace-mapping sites of the clinical VT coincided with areas of LGE. One possible explanation for the low correlation between EAM and LGE-CMR is the non-transmurality of the fibrosis in patients with NIDCM. A previous study in post-infarct patients demonstrated that median bipolar voltage <1.5 mV was only found in segments demonstrating ≥75% infarct transmurality (35). In a recently published article, Zeppenfeld et al. found that EAM voltages showed a linear relationship with the LV wall thickness and the amount of fibrosis in patients with non-ischemic DCM. However, no cutoff value for the voltage could be found to reliably delineate fibrotic areas in NIDCM (36). Regarding the quantification of the arrhythmogenic substrate, we could not find any correlation between the amount of LGE and the size of the low-voltage areas (endo- or epicardial), which can be explained by the impact of LGE transmurality as well as the sparse distribution of the LV fibrosis. In this regard, an advantage of the LGE-CMR is that it can visualize the presence of intramyocardial and epicardial scar which are not visible by endocardial EAM. The reason is that the bipolar EAM has narrower field of view and proved insensitive to delineate scar that lies deeper within the myocardium (37). Previously, Hutchinson et al. reported that by using a unipolar 8.27 mV threshold endocardial it was possible to identify epicardial bipolar low-voltage areas consistent with macroscopic scarring in patients with NIDCM and normal endocardial bipolar voltage (38). However, we found that the agreement between LGE and unipolar maps using this cutoff of 8.27 mV was poor. After adjusting the unipolar and bipolar threshold on the basis of CMR, the resulting median thresholds for the bipolar and unipolar low-voltage maps were 1.5 mV and 5 mV respectively, which are close to those observed in a previous study (37). 4.1 Conclusions LGE was observed in approximately one-third of the patients with dilated cardiomyopathy of non-ischemic origin and ventricular arrhythmias. LGE was seen mainly in patients with sustained VT. The agreement between the distribution or the extent of LGE and bipolar low-voltage areas was fairly poor. No particular cutoff values for bipolar and unipolar electro-anatomical maps could be found. On the other hand, most VT exits in patient with sustained VT were found in areas of LGE. The procedural success after VA ablation were related to LGE volume only.