Prognostic value of QT interval parameters for mortality risk stratification in Chagas' disease: results of a...

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.