Chagas disease is endemic to the Americas, infecting between 16-18 million individuals. In immigrant populations in the United States from endemic areas, it is estimated up to 4.9% may be asymptomatic carriers of Trypanosoma cruzi, the organism which causes Chagas disease. Between 10-20% of these patients progress to development of end-stage cardiomyopathy with a high associated morbidity. Following acute disease, patients enter into an indeterminate phase which can last 10-20 years. The earliest sign of cardiac involvement usually is electrocardiogram abnormalities. The most common abnormality is right bundle branch block (RBBB), followed by left anterior fascicular block (LAFB), and left bundle branch block (LBBB). Recent studies have shown that treatment of patients at this stage with antiparasitics may delay the progression of overt cardiomyopathy.

At the University of California, Los Angeles, there is a large population of immigrant patients from countries endemic to Chagas disease. The researchers propose that screening patients with conduction abnormalities on electrocardiogram may be a potentially useful method to identify patients with early cardiac manifestations of Chagas disease. The researchers hope to enroll approximately 300 individuals with RBBB, LAFB or LBBB on electrocardiogram to determine the incidence of Chagas disease in this patient population.