148 Heart rate variability patterns according to sleep-waking states in healthy prepubertal children: Lasting effects of iron deficiency anemia in infancy

Abstract

s of 3rd International Congress of the Association of Sleep Medicine (WASM) / Sleep Medicine 10, Suppl. 2 (2009) S1–S83 S41 148 Heart rate variability patterns according to sleep-waking states in healthy prepubertal children: Lasting effects of iron deficiency anemia in infancy S. Duran1, C. Algarin1, C. Martinez1, S. Reyes1, R. Chamorro1, M. Garrido2, B. Lozoff3, P. Peirano2. 1INTA, University of Chile; 2INTA, UNiversity of Chile; 3CHGD, University of Michigan Introduction: Iron deficiency is the most prevalent nutritional deficiency in the world. There is a consistent body of evidence on the lasting effects of early iron deficiency on several aspects of physiology, including sleep-wake patterns. However, the potential effect on autonomic regulation is unknown. Objective: To evaluate heart rate patterns as a function of sleep-wake states in healthy prepubertal children with (FIDA) and without (controls) iron deficiency anemia in infancy. Methods: We conducted nighttime polysomnographic recordings in 138 ten-year-old children (FIDA = 88 and controls = 50, 40% and 46% female, respectively). From the electrocardiographic signal, the following patterns were established for each sleep-wake stage (NREM sleep stages 1, 2 and 3-4 (or SWS), REM sleep and wakefulness): (i) RR interval (heart rate), (ii) heart rate variability (HRV) high-frequency component (HF or vagal predominance), and (iii) HRV low-frequency component (LF or sympathetic predominance). The balance of sympathetic and vagal tone was established by the LF/HF ratio. Results: Compared with controls, the FIDA group had shorter RR interval in NREM sleep stages 1 and 2 and wakefulness, and higher LF/HF ratio in stage 2 NREM sleep (p<0.05). When dividing the groups according to sex, FIDA girls had shorter RR intervals in all NREM sleep stages relative to controls (p<0.05). FIDA boys differed from controls by shorter RR in wakefulness and higher LF/HF ratio in NREM sleep stage 2 and SWS (p<0.05). Conclusions: These results show differences in heart rate and HRV patterns between healthy FIDA and control prepubertal children, with higher sympathetic tone during wakefulness and NREM sleep in the FIDA group. The findings support the existence of long-lasting effects of early iron deficiency anemia on autonomic regulation during sleep and wakefulness. Support: Fondecyt 1070668 and NIH HD33487 grants. 149 MOEBIUS SYNDROME ASSOCIATEDWITH SEVERE OSAHS TREATED WITH CPAP (CONTINUOUS POSITIVE AIRWAY PRESSURE) E.H. Ferruzzi, A.C. Casarotto, F.A. Borges, J.A.M. Torraca, J.L.H. Ferruzzi.