Respiratory effect to heartbeat fluctuations in neonates

Coherence between heartbeat and respiratory intervals of early neonates occurring for 4 days after birth was studied by the computer analysis. Patterns of the first-joint R-R interval histogram, relation between nth and (n + 1)th R-R interval, in neonates are classified into three. In the first pattern of a neonate, just after birth, the relation curve dispersed linearly on the histogram, and coherence between R-R interval power spectrum density (PSD) and breathing PSD shows peak. But, a couple of hours later, the relation of the joint interval histogram is grouped like a spot temporally and the coherence does not show peak. One more hour later, the relation curve begins to disperse linearly again and spreads widely as the time goes by. Then, peaks appear again in the coherence.