Myocarditis in admitted patients with dengue fever

Purpose: Cardiac involvement in dengue fever is underdiagnosed due to low index of clinical suspicion and its contribution to hemodynamic instability in severe dengue is not well known.

Methods: A prospective observational study was conducted among admitted patients ≥ 14 years of age having confirmed dengue fever. Patients on medications affecting heart rhythm/rate, pre-existing heart disease and electrolyte abnormalities were excluded. A baseline electrocardiography (ECG), Trop-I and NT-proBNP were done for all patients. The biomarkers were measured using enzyme-linked fluorescent assay and recommended cut-off were used. Patients with elevated biomarkers underwent 2-dimensional echocardiography. Diagnosis of myocarditis was as per European Society of Cardiology (ESC) 2013 criteria.

Results: A total of 182 patients were recruited with mean age of 30 ± 12.6 years and 31% were females. Dengue with warning signs was present in 85 (47%) and severe dengue in 60 (33%) patients. ECG abnormalities were observed in 44 (24%) patients, biomarkers were elevated in 27 (15%) patients and 11 (6%) patients had echocardiographic abnormalities. According to ESC 2013 criteria, dengue fever with myocarditis was diagnosed in 13 [7.1% (95% CI 3.4-10.9)] patients. The patients with myocarditis were more likely to have shortness of breath, bleeding manifestations and higher respiratory rate at baseline. Clinical features of fluid overload were more common (69% vs. 1.7%, p < 0.01) and the duration of hospital stay longer in myocarditis group (7 ± 4.3 vs. 4.8 ± 1.9 days, p < 0.01).

Conclusion: Myocarditis among admitted dengue patients is not uncommon and may lead to increased morbidity.

Keywords: Cardiac enzymes; Dengue; Echocardiography; Myocarditis.