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Prognostic value of QT interval parameters for mortality risk stratification in Chagas' disease: results of a
Gil Salles1, Sergio Xavier, Andrea Sousa
1Department of Internal Medicine, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. gilsalles@hucff.ufrj.br
Insights
QT interval dispersion (QTd) and left ventricular end-systolic dimension are key predictors of mortality in Chagas' disease patients. These ECG and echocardiographic markers improve risk stratification for better patient outcomes.
Area of Science:
- Cardiology
- Medical Diagnostics
- Public Health
Background:
- QT interval parameters are recognized prognostic markers for arrhythmogenicity and cardiovascular mortality.
- These parameters have not been previously evaluated in the context of Chagas' disease.
Purpose of the Study:
- To investigate the prognostic value of electrocardiographic (ECG) QT interval parameters in patients with chronic Chagas' disease.
- To identify predictors of mortality, including all-cause, Chagas' disease-related, and sudden cardiac death.
Main Methods:
- A long-term follow-up study involving 738 outpatients in the chronic phase of Chagas' disease.
- Measurement of maximal heart rate-corrected QT (QTc) and T-wave peak-to-end (TpTe) intervals, dispersions (QTd, TpTe), and variation coefficients from 12-lead ECGs.
- Collection of clinical, radiological, and echocardiographic data; primary end points were mortality outcomes.
Main Results:
- During 58+/-39 months follow-up, 62 patients died (54 Chagas' disease-related, 40 sudden cardiac death).
- Multivariate Cox analysis identified QT-interval dispersion (QTd) and left ventricular (LV) end-systolic dimension as the strongest independent predictors of mortality.
- Other significant predictors included heart rate, pathological Q waves, frequent premature ventricular contractions (PVCs), and isolated left anterior fascicular block (LAFB).
Conclusions:
- Electrocardiographic QTd and echocardiographic LV end-systolic dimension are crucial mortality predictors in Chagas' disease.
- ECG findings like pathological Q waves, frequent PVCs, and LAFB, along with heart rate, further refine mortality risk stratification.
- These findings highlight the importance of specific ECG and echocardiographic parameters for prognostication in Chagas' disease.
Background:
QT interval parameters are potential prognostic markers of arrhythmogenicity risk and cardiovascular mortality and have never been evaluated in Chagas' disease.
Methods And Results:
Outpatients (738) in the chronic phase of Chagas' disease were enrolled in a long-term follow-up study. Maximal heart rate-corrected QT (QTc) and T-wave peak-to-end (TpTe) intervals and QRS, QT, JT, QTapex, and TpTe dispersions and variation coefficients were measured manually and calculated from 12-lead ECGs obtained on admission. Clinical, radiological, and 2-dimensional echocardiographic data were also recorded. Primary end points were all-cause, Chagas' disease-related, and sudden cardiac mortalities. During a follow-up of 58+/-39 months, 62 patients died, 54 of Chagas' disease-related causes and 40 suddenly. Multivariate Cox survival analysis revealed that the QT-interval dispersion (QTd) (hazard ratio, 1.45; 95% confidence interval, 1.29 to 1.63; P<0.001, for 10-ms increments) and left ventricular (LV) end-systolic dimension (hazard ratio, 1.36; 95% confidence interval, 1.21 to 1.53; P<0.001, for 5-mm increments) were the strongest independent predictors for all end points. The maximum QTc interval (QTcmax) could substitute for QTd with a worse predictive performance. Other predictors were heart rate, presence of pathological Q waves, frequent premature ventricular contractions (PVCs), and isolated left anterior fascicular block (LAFB) on the ECGs. Kaplan-Meier survival curves demonstrated that a QTd > or =65 ms or a QTcmax > or =465 ms1/2 discriminated the 2 groups with significantly different prognoses.
Conclusions:
Electrocardiographic QTd and echocardiographic LV end-systolic dimension were the most important mortality predictors in patients with Chagas' disease. Heart rate, the presence on ECG of pathological Q waves, frequent PVCs, and isolated LAFB refined the mortality risk stratification.
