Autonomic dysfunction in 2009 pandemic influenza A (H1N1) virus-related infection: a pediatric comparative study

Relationship between respiratory morbidity and influenza virus has been well-documented in infants, whatever their age. However, in spite of severe cardiac and respiratory events of central origin, autonomic dysfunction potentially induced by this virus is poorly understood. We thus explored the autonomic nervous system (ANS) profile of infected infants during the 2009 pandemic influenza disease.

A group of 10 consecutive infants (5<1 year and 5>1 year) presenting with nvH1N1 infection was evaluated with heart rate variability (HRV) and spontaneous baroreflex (SBR) through a recording during a 15-minute period of quiet sleep as well as 24h holter monitoring. The same recordings were performed in 10 control subjects, paired for gestational and postnatal age. HRV sympathetic and parasympathetic (VLF, LF and HF) indices were obtained using spectral-domain analysis, and spontaneous baroreflex sensitivity (SBR) using simultaneous non-invasive continuous measure of arterial pressure and heart rate.

The group of infants less than 1 year had similar value as control group. Conversely, the group of infants more than 1 year showed significant lower spectral total power values (Ptot: 3347 vs. 5926 ms(2)/Hz, p<0.1) and significant lower VLF, LF and HF indices (all p<0.05) than the control group.

nvH1N1 infection in child could be associated with severe central autonomic dysfunction. Due to potential severe consequences, a systematic evaluation of autonomic regulation should be performed in order to avoid dramatic events.