ECG changes and their utility in adult Vietnamese patients with non-severe dengue

Dengue may affect the heart, manifesting as asymptomatic electrocardiographic (ECG) abnormalities to fulminant myocarditis. The role of routine ECG monitoring in dengue management remains unclear. We, therefore, studied ECG changes in patients with non-severe dengue. In this observational study, we performed and interpreted 12-lead ECGs (admission, discharge and follow up) on hospitalised Vietnamese adults with confirmed dengue and measured the PR, QRS, and Fridericia-corrected QT intervals (QTcF). A total of 330 ECGs were performed in 136 patients (64 females; median age, 24 years; range, 16–72 years). Of these, 132 patients had WHO-defined non-severe dengue and 4 had severe dengue. Elevated CK-MB fractions (> 25 IU/L) were detected in 64 of 134 patients (47.8%). The most common ECG abnormality was sinus bradycardia (< 60 beats/min), with 54 episodes occurring in 39 patients (28.7%), most frequently on illness day 10, 9/34 (26.5%) patients. The mean QTcF increased during the first 10 illness days in parallel with a decrease in mean heart rate; only 3 females (461–501 ms) and 1 male (460 ms) had sex-specific QTcF prolongation (≥ 460 ms female, ≥ 450 ms male). Female sex and illness day were significant predictors of QTcF variability over time. Pathological T-wave inversion in the inferior (II, III, aVF) and lateral chest (V5, V6) leads were observed in 12 patients (8.8%), and were mostly transient. ECG changes associated with nonsevere dengue in predominantly young Vietnamese adults without comorbidities were mostly mild, non-specific, and transient with limited impact on the QTcF interval. Routine ECGs in non-severe dengue in our setting did not provide clinically actionable information.