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Electrocardiographic Abnormalities in Patients With Novel H1N1 Influenza Virus Infection

https://doi.org/10.1016/j.amjcard.2010.06.078Get rights and content

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.

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Methods

All patients admitted to the Internal Medicine Department of the General Hospital “G. Hatzikosta” of Ioannina, Greece, with the diagnosis of novel H1N1 infection were included in this study. Diagnosis was confirmed by real-time polymerase chain reaction on nasopharyngeal or oropharyngeal swabs. Electrocardiography was performed in all patients on presentation to the emergency department and subsequently daily. Typical laboratory screening was performed in all patients admitted. All patients

Results

Fifty patients were admitted to the Internal Medicine Department with definite diagnoses of novel H1N1 influenza infection. Of these, 14 patients exhibited ECG abnormalities on admission. The epidemiologic, clinical, and laboratory characteristics of the 14 patients with ECG abnormalities and the 36 patients with persistently normal ECG findings are listed in Table 1. The ECG abnormalities encountered are listed in Table 2.

T-wave inversions and ST-segment depression were the prominent findings.

Discussion

In the present study, ECG abnormalities were often encountered in hospitalized patients with novel H1N1 influenza, with the percentage reaching 28%. It should be noted, however, that these patients exhibited disease of relatively moderate severity necessitating hospitalization; thus, this percentage may overestimate the actual percentage of such manifestations in the overall population infected with the novel H1N1 influenza virus. Yet an earlier study of patients with influenza2 treated at home

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