ECG DETECTION OF MURINE CHAGASIC CARDIOMYOPATHY

Chagas' disease, induced by Trypanosoma cruzi, is a common cause of infectious myocarditis. Recent clinical treatment trials and vaccine studies indicate that chagasic immunopathology is directed against the parasite and not self-antigens. Therefore, vaccines may have the potential to protect against disease progression. Certain combinations of mouse and parasite strains produce significant histopathology and can be used for safety analyses of new vaccination strategies. The goals of this study were to determine (1) whether the development of chagasic cardiomyopathy in the murine model could be identified by electrocardiogram (ECG); and (2) whether these potential chagasic ECG changes would correlate with histopathologic findings. Groups of BALB/c, C57BL/6, and C3H mice were infected with different parasite strains (Tulahuen, Brazil, or Sylvio-X10/4) and evaluated weekly by ECG. Selected tissues from subsets of mice were harvested periodically for blinded histologic evaluation. Significantly increased proportions of BALB/c mice infected with Brazil and Tulahuen strain parasites displayed prolonged QT intervals. Prolonged mean QT intervals detected in infected BALB/c mice significantly correlated with chagasic histopathologic changes. These results indicate that ECG can be used as a non-invasive method to screen for immune-mediated damage resulting in chagasic cardiomyopathy in the murine model.