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Doctoral Thesis
DOI
https://doi.org/10.11606/T.17.2022.tde-08082022-112133
Document
Author
Full name
Maria Fernanda Braggion Santos
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2022
Supervisor
Committee
Schmidt, Andre (President)
Almeida Filho, Oswaldo Cesar de
Coelho Filho, Otavio Rizzi
Pazin Filho, Antonio
Title in Portuguese
Padrões eletrocardiográficos da miocardiopatia chagásica e sua correlação com a presença e quantificação de fibrose miocárdica e função ventricular esquerda avaliados por ressonância nuclear magnética cardíaca
Keywords in Portuguese
Doença de Chagas
Eletrocardiograma
Escore de Selvester
Fibrose miocárdica
Miocardiopatia chagásica
Ressonância magnética cardíaca
Abstract in Portuguese
Introdução: A miocardiopatia chagásica (MC) resulta de agressões que levam à fibrose miocárdica (FM). Para avaliação inicial da doença, utiliza-se o eletrocardiograma (ECG), exame acessível e de baixo custo. A detecção não invasiva da fibrose é possível através da ressonância magnética cardíaca (RMC), porém trata-se de exame de maior custo e menor disponibilidade. O presente estudo tem como objetivo correlacionar achados do ECG através do escore de Selvester (escore de QRS), desenvolvido para estimar a porcentagem de FM; com a extensão da FM e fração de ejeção do ventrículo esquerdo (FEVE) quantificadas pela RMC, na doença de Chagas (DC). Métodos: Análise retrospectiva do ECG e RMC, realizados no intervalo máximo de 1 ano, entre 2010 e 2018, de 194 pacientes com DC seguidos no HCFMRP-USP. Em 171 pacientes foi possível calcular o escore de Rassi; escore clínico preditor de mortalidade em 10 anos em pacientes com MC. Variáveis contínuas foram demonstradas através de medianas e intervalos interquartis e variáveis categóricas foram expressas através de números totais e porcentagens. O coeficiente de correlação de Spearman foi utilizado para avaliar a relação entre o escore de Selvester, FM e FEVE avaliadas pela RMC. A análise de Bland-Altman foi feita para comparar a porcentagem de fibrose estimada pelo escore de QRS e medida pela RMC. Os pacientes foram divididos em tercis de acordo com o escore de Selvester e o teste de Kruskal-Wallis foi aplicado para comparar a quantidade de fibrose e a FEVE entre os grupos. Curvas ROC foram geradas para definir pontos de corte do escore de QRS para identificar: fibrose≥10% da massa do ventrículo esquerdo; fibrose≥12,3 gramas, FEVE<50% ou FEVE<35%. De acorco com o escore de Rassi, os pacientes foram divididos em 3 grupos de risco (baixo, intermediário e alto) e valores do escore de Selvester foram avaliados pelo teste de Kruskal-Wallis para cada grupo. Valores de p<0,05 foram considerados estatisticamente significativos. Resultados: Os pacientes eram em sua maioria do sexo feminino (98 mulheres, 50,5%) com mediana de idade de 56 [44-67] anos. A correlação entre estimativa de FM pelo escore de Selvester e quantificada pela RMC foi moderada (r=0,45, p < 0,001), assim como a correlação entre o aumento do escore de QRS e a redução da FEVE (r=0,42, p < 0,001). O gráfico de Bland-Altman demonstrou uma menor concordância entre os métodos para valores mais altos do escore de QRS, além de uma tendência do escore de Selvester em superestimar a porcentagem de FM. Escore de QRS≥5 foi associado a fibrose ≥12,3 gramas, fibrose ≥10% da massa do VE e FEVE< 50%. Escore de QRS ≥6 foi associado com FEVE<35% com boa especificidade. Os pacientes de alto risco pelo escore de Rassi apresentaram um escore de QRS mediano de 5 [3-9] pontos. Conclusão: O aumento do escore de Selvester na MC apresentou correlação moderada com o aumento de FM e com a redução da FEVE, avaliadas através da RMC. Valores do escore de QRS tendem a superestimar a porcentagem de FM, sendo que valores mais baixos parecem apresentar melhor correlação com a RMC. Ainda, valores de escore de Selvester acima de 5 ou 6 pontos associamse a maior acometimento do ventrículo esquerdo na MC e potencialmente estão associados a piores desfechos clínicos.
Title in English
Electrocardiographic abnormalities in chronic Chagas cardiomyopathy and its correlation with presence and burden of myocardial fibrosis and left ventricular ejection fraction measured by cardiac magnetic resonance
Keywords in English
Cardiac magnetic resonance
Chagas disease
Chronic Chagas' cardiomyopathy
Electrocardiogram
Myocardial fibrosis
Selvester score
Abstract in English
Background: Chronic Chagas' cardiomyopathy (CCC) is as consequence of several insults resulting in myocardial fibrosis (MF). Electrocardiogram (ECG) is a simple exam, which is part of initial evaluation of patients with CCC. Detection of MF is possible noninvasively through cardiac magnetic resonance (CMR). However, it is an expensive and not widely available method. This study aims to correlate ECG Selvester score (or QRS score); which was developed to estimate percentage of MF, with quantification of MF and left ventricular ejection fraction (LVEF) through CMR analysis, in patients with Chagas disease (CD). Methods: Retrospective analysis of ECG and CMR exams, performed within one year, between 2010 and 2018, of 194 patients with CD, followed in our outpatient clinics. Rassi score, which is a risk score for predicting death in patients with CCC, was evaluated in 171 patients. Continous variables were presented as median and interquartile range (IQR) whereas categorical data were summarized as frequencies and percentages. Spearman's rank correlation coeficiente was used to evaluate the correlation between estimated MF by QRS score and quantified MF through CMR, and between QRS score and LVEF. Bland-Altman plot was applied to compare percentage of MF estimated by Selvester score and measured by CMR. Patients were divided in tertiles based on QRS score values and Kruskal-Wallis test was applied to compare MF and LVEF among the groups. Receiver Operating Characteristic curves (ROC curve) were generated to define cut-off values with the best accuracy to identify MF≥10% of left ventricular mass, MF≥12.3 grams, LVEF<50% or LVEF<35%. According to Rassi score classification, patients were separated in 3 groups (low, intermediate, and high risk), and QRS score values were evaluated applying Kruskal-Wallis test. P-values <0.05 were considered statistically significant. Results: A total of 98 (50.5%) participants were women. Median age was 56 years (IQR: 44-67). Correlation between QRS score and MF quantified by CMR was moderate (r=0.45, p < 0.001), as well as the correlation between QRS score and LFEV, although negative (r= -0.42, p < 0.001). Bland-Altman plot showed worse agreement between methods for higher values of QRS score, and a trend to Selvester score to overestimate percentage of MF. QRS score≥5 was correlated to MF ≥12.3 grams, MF≥ 10% of left ventricular mass, and LVEF< 50%. QRS score≥6 was associated to LVEF<35% with good specificity. Patients classified as high risk by Rassi score had a median of QRS score of 5 points (IQR: 3-9). Conclusion: Higher QRS score values in CCC had a moderate correlation with higher burden of MF and worse LVEF measured by CMR. QRS score values tend to overestimate percentage of MF, whereas lower values of QRS seem to have a better correlation with CMR. Still, Selvester score above 5 ou 6 points are associated to more significant LV impairment, and potentially are related to worse outcomes.
 
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Publishing Date
2022-08-16
 
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