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Electrocardiographic ventricular repolarization parameters in chronic Chagas' disease as predictors of asymptomatic
Gil F Salles1, Claudia R L Cardoso, Sergio S Xavier
1Department of Internal Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. gilsalles@hucff.ufrj.br
Insights
Electrocardiographic repolarization, specifically QT dispersion (QTd), can predict left ventricular systolic dysfunction in Chagas
Area of Science:
- Cardiology
- Infectious Diseases
- Medical Imaging
Background:
- Chagas' disease is a parasitic infection with significant cardiac implications.
- Electrocardiographic repolarization parameters are established markers for arrhythmogenic risk.
- These repolarization parameters have not been extensively evaluated in the context of Chagas' disease.
Purpose of the Study:
- To investigate the association between electrocardiographic repolarization parameters and left ventricular (LV) systolic function in chronic Chagas' disease patients.
- To assess the predictive value of these parameters for identifying LV dysfunction.
Main Methods:
- A cross-sectional study was conducted on 738 adult outpatients with chronic Chagas' disease.
- Maximal QTc, T wave peak-to-end (TpTe) intervals, and dispersions of QT, QTapex (QTa), IT, and TpTe intervals were measured from standard 12-lead ECGs.
- Clinical, radiological, ECG, and echocardiographic data were collected and analyzed.
Main Results:
- Patients with moderate or severe LV systolic dysfunction exhibited significantly increased repolarization parameters.
- QT dispersion (QTd) demonstrated the best predictive performance for LV dysfunction (80% specificity, 67% sensitivity for values >60 ms) in a subgroup of patients with abnormal ECGs and no heart failure.
- A multivariate model including cardiomegaly, QTd >60 ms, male gender, and frequent premature ventricular contractions (PVCs) showed high predictive accuracy (90% specificity, 71% sensitivity) for LV dysfunction.
Conclusions:
- QTd is associated with LV systolic function and can predict asymptomatic dysfunction in chronic Chagas' disease.
- Cardiomegaly, frequent PVCs, and male sex further refine the stratification of LV function in these patients.
Abstract:
Electrocardiographic repolarization parameters are potential markers of arrhythmogenic risk and have not been evaluated in Chagas' disease. The aim of this report was to investigate their associations with LV systolic function assessed by two-dimensional echocardiography. In a cross-sectional study involving 738 adult outpatients in the chronic phase of Chagas' disease, maximal QTc and T wave peak-to-end (TpTe) intervals, and QT, QTapex (QTa), IT and TpTe interval dispersions, and variation coefficients were measured and calculated from 12-lead standard ECGs. Clinical, radiological, ECG, and echocardiographic data were recorded. In bivariate statistical analysis, all repolarization parameters were significantly increased in patients with moderate or severe LV systolic dysfunction, and these patients showed more clinical, radiologic, and ECG abnormalities. Receiver operating characteristic curve analysis demonstrated that isolatedly QTd had the best predictive performance for LV dysfunction, with an 80% specificity and 67% sensitivity for values >60 ms in the subgroup of chagasic patients with abnormal ECGs and no heart failure. Multivariate logistic regression selected, as the best predictive model for LV dysfunction in this subgroup of patients, the presence of cardiomegaly on chest X ray (OR 14.06, 95% CI, 5.54-35.71), QTd >60 ms (OR 9.35, 95% CI, 4.01-21.81), male gender (OR 7.70, 95% CI, 2.98-19.91) and the presence of frequent premature ventricular contractions (PVCs) on ECG (OR 4.06, 95% CI, 1.65-9.97). This model showed 90% specificity and 71% sensitivity. In conclusion, QTd was associated to LV systolic function and could be used to predict asymptomatic dysfunction in chronic Chagas' disease. The presence of cardiomegaly, frequent PVCs, and male sex refined LV function stratification in these patients.