Spectral analysis of heart variability in the newborn infant

We investigated the relationship between spectral power and both mean heart rate (HR) and heart rate variability (HRV). Spectral power was calculated using digital heart rate recordings from term infants. Regression analysis revealed a positive correlation between low-frequency (LF) sympathetic powe r and HR, and a negative correlation between high-frequency (HF) parasympat hetic power and HR. HRV correlated positively in all regions of the power s pectrum, In awake infants, the contribution of HF power to total power (HF/ TP) was significantly decreased, LF power tended to be greater, however, th is trend was not statistically significant. By following expected autonomic patterns, the findings of this study confirm that spectral analysis provid es a noninvasive method for the assessment of autonomic activity influencin g the newborn heart. The correlation between spectral power and HRV can ser ve as an additional tool in the study of autonomic dysfunction. Copyright ( C) 2000 S. Karger AG, Basel.