Evaluation of cardiac involvement during dengue viral infection.

Background:  Dengue is a disease whose clinical manifestations range from asymptomatic infections to a severe disease. There have been some previous reports of myocardial involvement in dengue, but this association has not been completely established.

Methods:  From January to July of 2011, patients hospitalized with dengue, confirmed through dengue nonstructural protein 1 and/or immunoglobulin M detection, were included in this study and troponin I and N terminal fragment of B-type natriuretic peptide levels were determined. Patients with abnormal biomarkers underwent echocardiography and when any abnormality was detected, they underwent cardiac magnetic resonance imaging.

Results:  Eighty-one patients were evaluated and 12 patients (15%) presented with elevated biomarker levels. Compared to controls, they had higher leukocyte (P < .001) and platelet counts (P = .005); higher C-reactive protein (P = .02), and a lower viral load (P = .03). There was no difference according to clinical dengue classification; dengue hemorrhagic fever/dengue shock syndrome severity; duration of symptoms; or prevalence of secondary infection between the 2 groups. Two patients died secondary to cardiogenic shock before imaging studies. Necroscopic findings were compatible to myocarditis in both, and immunohistochemistry for dengue virus showed increased staining on mononuclear cells located in the myocardial tissue. Of the 10 patients who underwent echocardiography, depressed left ventricular ejection fraction (LVEF) was identified in 1, left ventricular segmental abnormalities with preserved LVEF in 2, and an important pericardial effusion with tamponade in another. Cardiac involvement was confirmed by CMR in these 4 patients.

Conclusions:  Dengue viruses were shown to cause cardiac disease with clinical manifestations ranging from mild elevation of biomarkers to myocarditis and/or pericarditis.