Heart rate recovery in patients with obstructive sleep apnea syndrome
To demonstrate the effects of obstructive sleep apnea syndrome (OSAS) on baroregulatory function by using heart rate recovery (HRR) parameters. Materials and methods: Fifty-four moderate and severe OSAS patients were included in the study. HRR was defined as the difference in heart rate between peak exercise and 1 min later; a value of 18 beats/min was considered abnormal. OSAS patients were enrolled in the study as group 1 (normal HRR; n = 12) and group 2 (abnormal HRR, n = 42). Left ventricular ejection fraction (LVEF, %) and other parameters were also measured by echocardiography in both groups. Results: There was no statistically significant difference between group 1 and group 2 with regard to resting heart rate, or basic clinical and echocardiographic features (P > 0.05). The apnea-hypopnea index (AHI) was negatively correlated with the value of maximal heart rate during exercise (P < 0.05). In group 1, the mean age and coronary artery disease were significantly lower (respectively, 55.68 ± 10.05, 60.50 ± 9.00 years; 47.2% (n = 34), 80% (n = 24): P < 0.05), whereas the mean values of LVEF and maximal heart rate during exercise were significantly higher in comparison to group 2 (respectively 52.13 ± 11.95%, 45.13 ± 11.74%; 141.42 ± 19.70, 121.17 ± 19.01/min). Conclusion: These results indicate that in OSAS baroregulatory function was impaired. This may show that baroreflex dysfunction is correlated with OSAS. The routine inclusion of HRR in the prognostic assessment of patients with OSAS may be warranted.
Key words: Heart rate recovery, obstructive sleep apnea syndrome