Purpose: To characterize the cardiac manifestations in severe pandemic (H1N1) 2009 virus [P(H1N1)2009v] infection.
Materials and methods: Adult patients admitted to the intensive care unit were recruited. Patients with an elevated troponin I (>1.5 ng/mL) and those requiring vasoactive agents had an echocardiogram. Myocardial injury was defined as elevated troponin I. Patients with reduced ejection fraction lower than 50% were diagnosed as having left ventricular systolic dysfunction. Myocarditis was presumed when myocardial injury was associated with global myocardial dysfunction. Myocardial injury and dysfunction were correlated with mortality and expressed as odds ratio (OR) with 95% confidence intervals (CI).
Results: Thirty-seven patients presented at 6.4 (SD 3.2) days of illness. Four patients had valvular heart disease and 1 preexisting ischemic heart disease. Seventeen (46%) patients had evidence of myocardial injury. Twenty of 28 patients in whom an echocardiogram was clinically indicated had left ventricular systolic dysfunction. Of these, 14 patients were diagnosed as having myocarditis, and most of them (12 patients) developed it early. Myocarditis was associated with longer duration of vasoactive agents (OR 1.46, 95% CI 1.06-2.02) and mortality. Patients with elevated troponin I had an increased risk of death (OR 8.7, 95% CI 1.5-60). A higher mortality was observed in patients with left ventricular systolic dysfunction (OR 9.6, 95% CI 1.7-58) compared with those in whom an echocardiogram was normal or not indicated.
Conclusion: In our cohort of severe P(H1N1)2009v infection, myocardial injury and dysfunction was frequent and associated with high mortality.
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