Electrocardiographic abnormalities in patients with novel H1N1 influenza virus infection

The cardiac effects imposed by the novel H1N1 influenza strain have not been elucidated until now. Electrocardiographic (ECG) abnormalities were evaluated in a series of 50 patients with confirmed novel H1N1 influenza infection. Epidemiologic and clinical characteristics, laboratory correlations, and the effect ECG abnormalities may exert on disease outcomes were prospectively studied. Of the 50 patients, 14 (28%) exhibited ECG changes on admission. Nine patients presented with T-wave inversions, while ST-segment depression was observed on the electrocardiograms of 6 patients. The presence of ECG changes did not correlate with age, gender, co-morbidities, the laboratory profiles of the patients, or the coexistence of lower respiratory tract involvement. None of the patients exhibited alterations in cardiac-specific biochemistry or cardiac ultrasonography. All ECG changes were transient and reversed during disease regression. Two patients with ECG changes and 1 with normal ECG findings required intensive care, the former 2 eventually dying. Among the remainder, the duration of hospitalization did not exhibit a significant difference between the 2 groups, although there was a trend toward fewer days of hospitalization in the patients with ECG changes. In conclusion, ECG abnormalities are frequently encountered during novel H1N1 influenza infection, but their presence does not indicate a direct pathogen effect to the myocardium; these alterations may necessitate admission in the first place but are transient and not correlated with preexisting patient characteristics or with outcomes.