Echocardiographic assessment of cardiac function during respiratory syncytial virus infection.

Respiratory syncytial virus infection has been associated with increased morbidity and mortality in infants with underlying cardiac and pulmonary disease. To understand better the cardiopulmonary interaction in patients with acute respiratory syncytial virus bronchiolitis, we performed M-mode echocardiograms and pulsed Doppler assessment of pulmonary arterial flow in 19 patients with structurally normal hearts during acute illness. Studies were repeated in 11 of these patients following complete recovery. Based on severity of respiratory compromise, patients were grouped into those with severe illness (ten patients) or mild illness (nine patients). Left ventricular dimensions and shortening fraction were used to assess left ventricular function. Right ventricular systolic time intervals and specific Doppler flow velocity measurements were used to assess right ventricular function and elevation of pulmonary artery pressure. Comparisons were made between patients with severe and mild illness and between acute and follow-up studies. No statistically significant differences in left ventricular function, right ventricular systolic time intervals, or Doppler flow measurements were observed. We conclude that in patients with structurally normal hearts, respiratory syncytial virus bronchiolitis is not associated with significant depression of cardiac performance or elevation in pulmonary resistance.