[ECG monitoring in full-term infants. Analysis of the rhythm and variability of heart rate].

BACKGROUND

Heart Rate (HR) and Heart Rate Variability (HRV) depend on the neural control to the heart. HRV can be measured from 24-hours function. Little information is available on cardiac rhythm and on autonomic nervous control to the heart at birth. The aims of the study weew: 1) to study the cardiac rhythm in healthy newborn babies; 2) to asses the normal values for HRV at birth.

METHODS

We studied 20 full term healthy newborn babies. Newborns underwent 24-hours ECG-Holter monitoring. Analysis was performed by a 750 A Del Mar Avionics Analyzer. We determined: Heart Rate (HR), number of extrasystoles, Standard Deviation of all R-R intervals over 24 hours (SDNN) and mean hourly HRV (HRVM). Results about HRV were matched with those of 50 healthy adults.

RESULTS

1. Average HR in the newborn babies was 108 (range: 55-198); we found high prevalence of supraventricular extrasystoles. 2) We determined reference value for HRV. SDNN was 55 +/- 17 ms in newborns. SDNN of adults was 132 +/- 25 ms (44% higher than in newborns; p < 0.001). HRVM was 46 +/- 14 ms in newborns and 76 +/- 14 ms (p < 0.001).

CONCLUSION

1. Larger intervals of HR in newborn babies compared to literature data and an high prevalence of supraventricular arrhythmias in full term healthy newborn babies. 2) Reference values for HRV in newborn babies. The low values of HRV confirm the immaturity of autonomic cardiac control.