Cardiac Fibrosis and Changes in Left Ventricle Function in Patients with Chronic Chagas Heart Disease.

Background: Chagas heart disease (CHD) is a slow progressing condition with fibrosis as the main histopathological finding.

Objectives: To study if cardiac fibrosis increases over time and correlates with increase in left ventricular (LV) size and reduction of ejection fraction (EF) in chronic CHD.

Methods: Retrospective study that included 20 individuals (50% men; 60±10 years) with chronic CHD who underwent two cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement with a minimum interval of four years between tests. LV volume, EF, and fibrosis mass were determined by cardiac MRI. Associations of fibrosis mass at the first cardiac MRI and changes in LV volume and EF at the second cardiac MRI were tested using logistic regression analysis. P values <0.05 were considered significant.

Results: Patients were classified as follows: A (n=13; changes typical of CHD in the electrocardiogram and normal global and segmental LV systolic function) and B1 (n=7; LV wall motion abnormality and EF≥45%). Mean time between cardiac MRI studies was 5.4±0.5 years. LV fibrosis (in %LV mass) increased from 12.6±7.9% to 18.0±14.1% between MRI studies (p=0.02). Cardiac fibrosis mass at baseline was associated with decrease in >5 absolute units in LV EF from the first to the second MRI (OR 1.48, 95% CI 1.03-2.13, p=0.03). LV fibrosis mass was larger and increased between MRI studies in the group that presented decrease in LV EF between the tests.

Conclusions: Even patients at an initial stage of CHD show an increase in myocardial fibrosis over time, and the presence of LV fibrosis at baseline is associated with a decrease in LV systolic function.