Arritmias ventriculares e hipertrofia ventricular esquerda na cardiomiopatia hipertrófica

FUNDAMENTO: Na Cardiomiopatia Hipertrófica (CMH), o grau de Hipertrofia Ventricular Esquerda (HVE) poderia influenciar o desenvolvimento de arritmias ventriculares. OBJETIVO: Analisar, na CMH, a associação entre a ocorrência de arritmias ventriculares no eletrocardiograma-Holter (ECG-Holter) e o grau de HVE determinado ao ecocardiograma pela espessura parietal máxima (EPM) e Índice de Massa (IM). MÉTODOS: Cinquenta e quatro pacientes consecutivos com CMH realizaram ECG-Holter de 24 horas e ecocardiograma para avaliação do grau de HVE através da EPM e IM. Foram estabelecidos dois níveis para a ocorrência de arritmias ventriculares: I - extrassístoles isoladas ou pareadas e II - Taquicardia Ventricular Não Sustentada (TVNS). RESULTADOS: Nos 13 pacientes (24%) com TVNS (nível II), houve maior frequência de EPM do ventrículo esquerdo (VE) > 21 mm (n = 10, 77%; 25 ± 4 mm) e IMVE > 144 g/m² (n = 10, 77%; 200 ± 30 g/m²), em relação àqueles que apresentavam apenas arritmia extrassistólica (nível I) (n = 41, 76%), em que essas medidas foram identificadas em, respectivamente, 37% (n = 15, 23 ± 1 mm), p = 0,023, e 39% (n = 16, 192 ± 53 g/m²) dos casos, p = 0,026. Os citados valores de corte foram determinados por curva ROC com intervalo de confiança de 95%. O registro de TVNS foi mais comum em pacientes com EPMVE > 21 mm e IMVE > 144 g/m² (8 de 13; 62%), do que naqueles com uma (4 de 13; 31%) ou nenhuma (1 de 13; 8%) variável ecocardiográfica acima dos valores de corte, p = 0,04. CONCLUSÃO: A ocorrência de arritmias ventriculares no Holter associou-se, na CMH, ao grau de HVE, avaliado pelo ecocardiograma através da respectiva EPM e IM.

Métodos não-lineares para avaliar mudanças na variabilidade da frequência cardíaca em pacientes com diabetes tipo 2

FUNDAMENTO: A variabilidade da frequência cardíaca (VFC) é um importante indicador da modulação autonômica da função cardiovascular. A diabetes pode alterar a modulação autonômica danificando as entradas aferentes, dessa forma aumentando o risco de doenças cardiovasculares. Foram aplicados métodos analíticos não lineares para identificar os parâmetros associados com VFC indicativos de alterações na modulação autonômica da função cardíaca em pacientes diabéticos. OBJETIVO: Analisamos as diferenças nos padrões da VFC entre pacientes diabéticos e controles saudáveis pareados por idade, utilizando métodos não-lineares. MÉTODOS: Plot de Poincaré Lagged, autocorrelação e análise de flutuação destendenciada foram aplicados para analisar a VFC em registros de eletrocardiograma (ECG). RESULTADOS: A análise do gráfico de Poincaré lagged revelou alterações significativas em alguns parâmetros, sugestivas de diminuição da modulação parassimpática. O expoente de flutuação destendencionada derivado de um ajuste em longo prazo foi maior que o expoente em curto prazo na população diabética, o que também foi consistente com a diminuição do input parassimpático. A função de autocorrelação do desvio dos intervalos inter-batimento exibiu um padrão altamente correlacionado no grupo de diabéticos em comparação com o grupo controle. CONCLUSÃO: O padrão de VFC difere significativamente entre pacientes diabéticos e indivíduos saudáveis. Os três métodos estatísticos utilizados no estudo podem ser úteis para detectar o início e a extensão da neuropatia autonômica em pacientes diabéticos.

A dissincronia mecânica é semelhante em diferentes padrões do bloqueio de ramo esquerdo

FUNDAMENTOS: O bloqueio do ramo esquerdo (BRE) e a presença de disfunção sistólica são as principais indicações de terapia de ressincronização cardíaca (TRC). A dissincronia ventricular mecânica pela ecocardiografia pode ajudar a identificar pacientes responsivos à TRC. O BRE pode mostrar diferentes padrões em sua morfologia. OBJETIVO: Comparar a prevalência de dissincronia mecânica em diferentes padrões de BRE em pacientes com disfunção sistólica esquerda. MÉTODOS: Analisaram-se 48 pacientes com fração de ejeção (FE) < 40% e BRE referidos consecutivamente para análise de dissincronia. Foram realizados ecocardiograma convencional e análise da dissincronia mecânica, interventricular e intraventricular, por 10 conhecidos métodos, usando modo M, Doppler e Doppler tecidual, sozinhos ou combinados. A morfologia do BRE foi categorizada pelo desvio esquerdo do eixo no plano frontal e duração de QRS > 150 ms. RESULTADOS: Eram 24 homens, com idade 60 ± 11 anos e FEVE de 29 ± 7%. Trinta e dois apresentavam QRS > 150 ms, e 22, ECG eixo entre -30º e +90º. A dissincronia interventricular foi identificada em 73% dos pacientes e a intraventricular em valores entre 37-98%. Portadores de QRS > 150 ms apresentaram maiores dimensões do átrio e ventrículo esquerdos, e menor FE (p < 0,05), e o desvio esquerdo do eixo associou-se a pior função diastólica e maior diâmetro atrial. A presença de dissincronia mecânica interventricular e intraventricular (10 métodos) foi semelhante entre os diferentes padrões de BRE (p = ns). CONCLUSÃO: Nos dois diferentes padrões eletrocardiográficos de BRE analisados, não foram observadas diferenças em relação à presença de dissincronia mecânica.

Preditores de internação hospitalar em pacientes com síncope atendidos em hospital cardiológico

FUNDAMENTO: No atendimento ao episódio sincopal é necessário estratificar o risco para melhor diferenciar pacientes que necessitam de internação hospitalar daqueles que podem ser liberados. Os critérios utilizados pelos médicos avaliadores desses pacientes em emergências cardiológicas em nosso meio são desconhecidos. OBJETIVOS: Analisar quais os critérios adotados para internação hospitalar, diferenciá-los dos utilizados nos pacientes liberados e compará-los com os preditores de alto risco definidos pelo escore de OESIL já validado para esse fim. MÉTODOS: Estudo transversal em pacientes diagnosticados com síncope na emergência em nossa instituição no ano de 2011. RESULTADOS: Dos 46.476 atendimentos realizados naquele ano, 216 foram descritos como síncope. Dos 216 pacientes analisados, 39% foram internados, sendo que as principais variáveis associadas à admissão foram síncope prévia, doença cardíaca conhecida, história negativa para acidente vascular encefálico no passado, ECG alterado e possuir plano de súde. Na comparação internação contra não internação, os escores OESIL 0-1 foram associados a maior chance de liberação hospitalar; os escores 2-3 apresentaram maior associação com internação. Um escore OESIL >2 demonstrou razão de chances 7,8 vezes maior de internação comparado com o escore 0 (p < 0,001; IC95%: 4,03-15,11). Aproximadamente 39% dos pacientes não tiveram definição etiológica e em 18% foi identificada uma causa cardiológica. CONCLUSÕES: Fatores como doença cardiovascular conhecida, história sincopal prévia, ausência de AVC prévio, possuir seguro de saúde e eletrocardiograma alterado foram os critérios utilizados pelos médicos em emergência para indicar internação hospitalar. Houve boa correlação entre os critérios clínicos e os critérios de risco do OESIL descritos na literatura.

Espessura do tecido subcutaneo como preditor independente de ruido em imagem de TC cardiaca

Fundamento: Há poucos dados sobre a definição de parâmetros simples e robustos para predizer artefato de imagem em tomografia computadorizada (TC) cardíaca. Objetivos: Avaliar o valor da simples medida da espessura do tecido subcutâneo (espessura pele-esterno) como preditor de artefato de imagem em TC cardíaca. Métodos: O estudo avaliou 86 pacientes submetidos a angiotomografia computadorizada cardíaca (ATCC) com sincronização prospectiva com ECG e avaliação de escore de cálcio coronário com 120 kV e 150 mA. A qualidade da imagem foi medida objetivamente pelo artefato de imagem na aorta em ATCC, sendo 'artefato baixo' definido como aquele < 30 UH. Os diâmetros torácicos anteroposterior e laterolateral, o artefato de imagem na aorta e a espessura pele-esterno foram medidos como preditores de artefato em ATCC. A associação de preditores e artefato de imagem foi avaliada usando-se correlação de Pearson. Resultados: A dose média de radiação foi 3,5 ± 1,5 mSv. O artefato de imagem médio na ATCC foi de 36,3 ± 8,5 UH, sendo o artefato de imagem médiona fase sem contraste do exame de 17,7 ± 4,4 UH. Todos os preditores foram independentemente associados com artefato em ATCC. Os melhores preditores foram espessura pele-esterno, com correlação de 0,70 (p < 0,001), e artefato de imagem na fases em contraste,com correlação de 0,73 (p < 0,001). Ao avaliar a habilidade de predizer artefato de imagem baixo, as áreas sob a curva ROC para o artefato de imagem na fases em contraste e para a espessura pele-esterno foram 0,837e 0,864, respectivamente. Conclusão: Tanto espessura pele-esterno quanto artefato de escore de cálcio são preditores simples e precisos de artefato de imagem em ATCC. Tais parâmetros podem ser incorporados aos protocolos de TC padrão para ajustar adequadamente a exposição à radiação.

Baroreflex Sensitivity and its Association with Arrhythmic Events in Chagas Disease

Background:Sudden death is the leading cause of death in Chagas disease (CD), even in patients with preserved ejection fraction (EF), suggesting that destabilizing factors of the arrhythmogenic substrate (autonomic modulation) contribute to its occurrence.Objective:To determine baroreflex sensitivity (BRS) in patients with undetermined CD (GI), arrhythmogenic CD with nonsustained ventricular tachycardia (NSVT) (GII) and CD with spontaneous sustained ventricular tachycardia (STV) (GIII), to evaluate its association with the occurrence and complexity of arrhythmias.Method:Forty-two patients with CD underwent ECG and continuous and noninvasive BP monitoring (TASK force monitor). The following were determined: BRS (phenylephrine method); heart rate variability (HRV) on 24-h Holter; and EF (echocardiogram).Results:GIII had lower BRS (6.09 ms/mm Hg) as compared to GII (11.84) and GI (15.23). The difference was significant between GI and GIII (p = 0.01). Correlating BRS with the density of ventricular extrasystoles (VE), low VE density (<10/h) was associated with preserved BRS. Only 59% of the patients with high VE density (> 10/h) had preserved BRS (p = 0.003). Patients with depressed BRS had higher VE density (p = 0.01), regardless of the EF. The BRS was the only variable related to the occurrence of SVT (p = 0.028).Conclusion:The BRS is preserved in undetermined CD. The BRS impairment increases as disease progresses, being more severe in patients with more complex ventricular arrhythmias. The degree of autonomic dysfunction did not correlate with EF, but with the density and complexity of ventricular arrhythmias.

Assessing Strategies for Heart Failure with Preserved Ejection Fraction at the Outpatient Clinic

Background: Heart failure with preserved ejection fraction (HFPEF) is the most common form of heart failure (HF), its diagnosis being a challenge to the outpatient clinic practice. Objective: To describe and compare two strategies derived from algorithms of the European Society of Cardiology Diastology Guidelines for the diagnosis of HFPEF. Methods: Cross-sectional study with 166 consecutive ambulatory patients (67.9±11.7 years; 72% of women). The strategies to confirm HFPEF were established according to the European Society of Cardiology Diastology Guidelines criteria. In strategy 1 (S1), tissue Doppler echocardiography (TDE) and electrocardiography (ECG) were used; in strategy 2 (S2), B-type natriuretic peptide (BNP) measurement was included. Results: In S1, patients were divided into groups based on the E/E'ratio as follows: GI, E/E'> 15 (n = 16; 9%); GII, E/E'8 to 15 (n = 79; 48%); and GIII, E/E'< 8 (n = 71; 43%). HFPEF was confirmed in GI and excluded in GIII. In GII, TDE [left atrial volume index (LAVI) ≥ 40 mL/m2; left ventricular mass index LVMI) > 122 for women and > 149 g/m2 for men] and ECG (atrial fibrillation) parameters were assessed, confirming HFPEF in 33 more patients, adding up to 49 (29%). In S2, patients were divided into three groups based on BNP levels. GI (BNP > 200 pg/mL) consisted of 12 patients, HFPEF being confirmed in all of them. GII (BNP ranging from 100 to 200 pg/mL) consisted of 20 patients with LAVI > 29 mL/m2, or LVMI ≥ 96 g/m2 for women or ≥ 116 g/m2 for men, or E/E'≥ 8 or atrial fibrillation on ECG, and the diagnosis of HFPEF was confirmed in 15. GIII (BNP < 100 pg/mL) consisted of 134 patients, 26 of whom had the diagnosis of HFPEF confirmed when GII parameters were used. Measuring BNP levels in S2 identified 4 more patients (8%) with HFPEF as compared with those identified in S1. Conclusion: The association of BNP measurement and TDE data is better than the isolated use of those parameters. BNP can be useful in identifying patients whose diagnosis of HF had been previously excluded based only on TDE findings.

Prevention of Pazopanib-Induced Prolonged Cardiac Repolarization and Proarrhythmic Effects

Background: Pazopanib (PZP) may induce prolonged cardiac repolarization and proarrhythmic effects, similarly to other tyrosine kinase inhibitors. Objectives: To demonstrate PZP-induced prolonged cardiac repolarization and proarrhythmic electrophysiological effects and to investigate possible preventive effects of metoprolol and diltiazem on ECG changes (prolonged QT) in an experimental rat model. Methods: Twenty-four Sprague-Dawley adult male rats were randomly assigned to 4 groups (n = 6). The first group (normal group) received 4 mL of tap water and the other groups received 100 mg/kg of PZP (Votrient® tablet) perorally, via orogastric tubes. After 3 hours, the following solutions were intraperitoneally administered to the animals: physiological saline solution (SP), to the normal group and to the second group (control-PZP+SP group); 1 mg/kg metoprolol (Beloc, Ampule, AstraZeneca), to the third group (PZP+metoprolol group); and 1mg/kg diltiazem (Diltiazem, Mustafa Nevzat), to the fourth group (PZP+diltiazem group). One hour after, and under anesthesia, QTc was calculated by recording ECG on lead I. Results: The mean QTc interval values were as follows: normal group, 99.93 ± 3.62 ms; control-PZP+SP group, 131.23 ± 12.21 ms; PZP+metoprolol group, 89.36 ± 3.61 ms; and PZP+diltiazem group, 88.86 ± 4.04 ms. Both PZP+metoprolol and PZP+diltiazem groups had significantly shorter QTc intervals compared to the control-PZP+SP group (p < 0.001). Conclusion: Both metoprolol and diltiazem prevented PZP-induced QT interval prolongation. These drugs may provide a promising prophylactic strategy for the prolonged QTc interval associated with tyrosine kinase inhibitor use.

Relationship between Neutrophil-To-Lymphocyte Ratio and Electrocardiographic Ischemia Grade in STEMI

Background: Neutrophil-to-lymphocyte ratio (NLR) has been found to be a good predictor of future adverse cardiovascular outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Changes in the QRS terminal portion have also been associated with adverse outcomes following STEMI. Objective: To investigate the relationship between ECG ischemia grade and NLR in patients presenting with STEMI, in order to determine additional conventional risk factors for early risk stratification. Methods: Patients with STEMI were investigated. The grade of ischemia was analyzed from the ECG performed on admission. White blood cells and subtypes were measured as part of the automated complete blood count (CBC) analysis. Patients were classified into two groups according to the ischemia grade presented on the admission ECG, as grade 2 ischemia (G2I) and grade 3 ischemia (G3I). Results: Patients with G3I had significantly lower mean left ventricular ejection fraction than those in G2I (44.58 ± 7.23 vs. 48.44 ± 7.61, p = 0.001). As expected, in-hospital mortality rate increased proportionally with the increase in ischemia grade (p = 0.036). There were significant differences in percentage of lymphocytes (p = 0.010) and percentage of neutrophils (p = 0.004), and therefore, NLR was significantly different between G2I and G3I patients (p < 0.001). Multivariate logistic regression analysis revealed that only NLR was the independent variable with a significant effect on ECG ischemia grade (odds ratio = 1.254, 95% confidence interval 1.120–1.403, p < 0.001). Conclusion: We found an association between G3I and elevated NLR in patients with STEMI. We believe that such an association might provide an additional prognostic value for risk stratification in patients with STEMI when combined with standardized risk scores.

Assessment of Autonomic Function by Phase Rectification of RRInterval Histogram Analysis in Chagas Disease

Background:In chronic Chagas disease (ChD), impairment of cardiac autonomic function bears prognostic implications. Phase‑rectification of RR-interval series isolates the sympathetic, acceleration phase (AC) and parasympathetic, deceleration phase (DC) influences on cardiac autonomic modulation.Objective:This study investigated heart rate variability (HRV) as a function of RR-interval to assess autonomic function in healthy and ChD subjects.Methods:Control (n = 20) and ChD (n = 20) groups were studied. All underwent 60-min head-up tilt table test under ECG recording. Histogram of RR-interval series was calculated, with 100 ms class, ranging from 600–1100 ms. In each class, mean RR-intervals (MNN) and root-mean-squared difference (RMSNN) of consecutive normal RR-intervals that suited a particular class were calculated. Average of all RMSNN values in each class was analyzed as function of MNN, in the whole series (RMSNNT), and in AC (RMSNNAC) and DC (RMSNNDC) phases. Slopes of linear regression lines were compared between groups using Student t-test. Correlation coefficients were tested before comparisons. RMSNN was log-transformed. (α < 0.05).Results:Correlation coefficient was significant in all regressions (p < 0.05). In the control group, RMSNNT, RMSNNAC, and RMSNNDCsignificantly increased linearly with MNN (p < 0.05). In ChD, only RMSNNAC showed significant increase as a function of MNN, whereas RMSNNT and RMSNNDC did not.Conclusion:HRV increases in proportion with the RR-interval in healthy subjects. This behavior is lost in ChD, particularly in the DC phase, indicating cardiac vagal incompetence.

Left Atrial Function in Patients with Chronic Chagasic Cardiomyopathy

Background:Chagas disease is a cause of dilated cardiomyopathy, and information about left atrial (LA) function in this disease still lacks.Objective:To assess the different LA functions (reservoir, conduit and pump functions) and their correlation with the echocardiographic parameters of left ventricular (LV) systolic and diastolic functions.Methods:10 control subjects (CG), and patients with Chagas disease as follows: 26 with the indeterminate form (GI); 30 with ECG alterations (GII); and 19 with LV dysfunction (GIII). All patients underwent M-mode and two-dimensional echocardiography, pulsed-wave Doppler and tissue Doppler imaging.Results:Reservoir function (Total Emptying Fraction: TEF): (p <0.0001), lower in GIII as compared to CG (p = 0.003), GI (p <0.001) and GII (p <0.001). Conduit function (Passive Emptying Fraction: PEF): (p = 0.004), lower in GIII (GIII and CG, p = 0.06; GI and GII, p = 0.06; and GII and GIII, p = 0.07). Pump function (Active Emptying Fraction: AEF): (p = 0.0001), lower in GIII as compared to CG (p = 0.05), GI (p<0.0001) and GII (p = 0.002). There was a negative correlation of E/e’average with the reservoir and pump functions (TEF and AEF), and a positive correlation of e’average with s’ wave (both septal and lateral walls) and the reservoir, conduit and pump LA functions.Conclusion:An impairment of LA functions in Chagas cardiomyopathy was observed.

Co-administration of Apelin and T4 Protects Inotropic and Chronotropic Changes Occurring in Hypothyroid Rats

AbstractBackground:One of the most important thyroid hormone targets is the cardiovascular system. Hemodynamic changes, such as decreased resting heart rate (HR), myocardial contractility, and cardiac output, and increased diastolic pressure and systemic vascular resistance, have been observed in hypothyroid patients. Moreover, in these patients, ECG changes include sinus bradycardia and low voltage complexes (P waves or QRS complexes).Objective:This study aimed at evaluating the prophylactic effect of apelin on HR changes and QRS voltage that occur in propylthiouracil (PTU)-induced hypothyroid rats.Method:In this study, 48 adult male Wistar rats weighing 170-235g were randomly divided into 6 groups: Control group (normal saline ip injection + tap water gavage); P group (PTU 0.05%, in drinking water); A group (apelin 200 µg.kg-1.day-1, ip); PA group [co-administration of PTU and apelin]; PT group [co-administration of PTU + T4 (0.2 mg/g per day, gavage)]; and PAT group (co-administration of PTU, apelin and T4). All experiments were performed for 28 consecutive days, and then the animals were anesthetized with an ip injection of ketamine (80 mg/kg) and xylazine (12 mg/kg). Lead II electrocardiogram was recorded to calculate HR and QRS voltage.Results:Heart rate and QRS voltage increased more significantly in the hypothyroid group that consumed both apelin and T4 (201 ± 4 beat/min, 0.71 ± 0.02 mv vs. hypothyroid 145 ± 9 beat/min, 0.563 ± 0.015 mv; respectively).Conclusion:The co-administration of apelin and T4 showed a protective effect on QRS voltage and HR in PTU‑induced hypothyroid rats.

Frequency of Cardiovascular Involvement in Familial Amyloidotic Polyneuropathy in Brazilian Patients

Background:Familial amyloidotic polyneuropathy (FAP) is a rare disease diagnosed in Brazil and worldwide. The frequency of cardiovascular involvement in Brazilian FAP patients is unknown.Objective:Detect the frequency of cardiovascular involvement and correlate the cardiovascular findings with the modified polyneuropathy disability (PND) score.Methods:In a national reference center, 51 patients were evaluated with clinical examination, electrocardiography (ECG), echocardiography (ECHO), and 24-hour Holter. Patients were classified according to the modified PND score and divided into groups: PND 0, PND I, PND II, and PND > II (which included PND IIIa, IIIb, and IV). We chose the classification tree as the statistical method to analyze the association between findings in cardiac tests with the neurological classification (PND).Results:ECG abnormalities were present in almost 2/3 of the FAP patients, whereas ECHO abnormalities occurred in around 1/3 of them. All patients with abnormal ECHO also had abnormal ECG, but the opposite did not apply. The classification tree identified ECG and ECHO as relevant variables (p < 0.001 and p = 0.08, respectively). The probability of a patient to be allocated to the PND 0 group when having a normal ECG was over 80%. When both ECG and ECHO were abnormal, this probability was null.Conclusions:Brazilian patients with FAP have frequent ECG abnormalities. ECG is an appropriate test to discriminate asymptomatic carriers of the mutation from those who develop the disease, whereas ECHO contributes to this discrimination.

Diagnosis of Rejection by Analyzing Ventricular Late Potentials in Heart Transplant Patients

Background: Heart transplant rejection originates slow and fragmented conduction. Signal-averaged ECG (SAECG) is a stratification method in the risk of rejection. Objective: To develop a risk score for rejection, using SAECG variables. Methods: We studied 28 transplant patients. First, we divided the sample into two groups based on the occurrence of acute rejection (5 with rejection and 23 without). In a second phase, we divided the sample considering the existence or not of rejection in at least one biopsy performed on the follow-up period (rejection pm1: 18 with rejection and 10 without). Results: On conventional ECG, the presence of fibrosis was the only criterion associated with acute rejection (OR = 19; 95% CI = 1.65-218.47; p = 0.02). Considering the rejection pm1, an association was found with the SAECG variables, mainly with RMS40 (OR = 0.97; 95% CI = 0.87-0.99; p = 0.03) and LAS40 (OR = 1.06; 95% IC = 1.01-1.11; p = 0.03). We formulated a risk score including those variables, and evaluated its discriminative performance in our sample. The presence of fibrosis with increasing of LAS40 and decreasing of RMS40 showed a good ability to distinguish between patients with and without rejection (AUC = 0.82; p < 0.01), assuming a cutoff point of sensitivity = 83.3% and specificity = 60%. Conclusion: The SAECG distinguished between patients with and without rejection. The usefulness of the proposed risk score must be demonstrated in larger follow-up studies.

Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease

Abstract The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas.