Development of a risk score to predict sudden death in patients with Chaga's heart disease

Abstract

Background: Sudden death is the most frequent mechanism of death in patients with chronic Chaga's cardiopathy, regardless of the degree of myocardial involvement. We developed a model to predict the risk of sudden death in patients with chronic Chaga's cardiopathy.

Methods: We retrospectively evaluated 373 patients. The association between the risk factors for chronic Chaga's cardiopathy and sudden death was assessed using Cox proportional-hazards analysis, and a risk score was determined. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive performance of the score and Kaplan Meier survival curves, which were stratified according to the score.

Results: During a mean follow-up period of 66±44months, 43 patients experienced sudden death. Four independent predictors were identified, each of which was assigned a number of points proportional to the following regression coefficients: QT-interval dispersion (3 points), syncope (2 points), ventricular extrasystoles (1 point), and severe dysfunction of the left ventricle (1 point). We calculated risk scores for each patient and defined three groups: low risk (0 to 2 points), intermediate (3 to 4 points), and high risk (>5 points). The mortality rates of the three groups were 1.5%, 25%, and 51%, respectively. The C statistic for the prediction score was 0.84, which demonstrated good clinical relevance of the model.

Conclusion: This simple risk score predicted sudden death in patients with chronic Chaga's heart disease.

Keywords: Chronic Chaga's cardiopathy; Risk score; Sudden death.