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.

Figure 1

Original simultaneous jugular venous tracing (A), brachial artery tracing (B), and apexcardiogram (C) obtained with a Jacquet’s polygraph between 1910 and 1914 by Chagas team. Note a transitory second-degree AV block (arrows). The resting ECG was unavailable at that time in Brazil. a: A wave of the jugular pulse; c: C wave of the jugular pulse. Courtesy of Fundo Instituto Oswaldo Cruz, Seção Hospital Evandro Chagas, Acervo Casa de Oswaldo Cruz.

Figure 2

Timeline of scientific construction of the Chronic Chagas Heart Disease. HC: Heart Catheterization; ECHO: Echocardiography; EMB: Endomyocardial Biopsy; MRI: Magnetic Resonance Imaging.