Abstract
BACKGROUND: The aim of this study was to investigate the effects of carbon-dioxide treatment on heart rate variability (HRV) parameters: mean RR interval (RRI), standard deviation of RR intervals (SDNN), root mean square of successive RR differences (RMSSD); and Porta and Guzik indices, as measures of heart rate asymmetry. MATERIALS AND METHODS: Twenty patients were enrolled (mean±SD, age=59±7.8 years). Measurements were performed before CO(2) treatment, at the beginning of treatment, at 15 min of treatment, immediately after and 1 h after the treatment. RESULTS: Significant increase in SDNN was found 1 h after the treatment when compared to that before it (p=0.011). There were no significant changes in other parameters. CONCLUSION: CO(2) treatment can influence the autonomic nervous system identified by SDNN changes. However, larger studies are required to confirm these results.