Sleep Apnea Syndrome And Bradycardia In Old Patients

Objective: To study the heart rate variability in old patients with sleep apnea syndrome, especially the bradycardia.Methods: 13 old patients diagnosed by means of polysomnography were enrolled, apneas and hypopneas were selected of each patient randomly into studying the heart rate variability before, during and after its happening. Moreover, we also studied the impact of type of apnea, duration of apnea, desaturation, sleep stage, arousal on heart rate variability.Results: Bradycardia could be seen almost in every apnea/hypopnea, and was significantly correlated to the length of apnea/hypopnea (P <0.05). The type of apnea had no significance. Bradycardia could be seen at early part of apnea/hypopnea, at the late part heart rate rose a little bit and then had a sharp elevation when respiratory restored. After that heart-rate-rising could still be found but late would drop to the original rate before apnea/hypopnea. Bradycardia occurred dominantly in sleep stage 2 and rapid-eye-movement stage. Bradycardia occurred independently from the decrease of oxygen saturation, a linear relationship couldn't be found. Arousal might play an important role in the variability of heart rate.Conclusion: Old patients with SAS could occur obvious bradycardia which is dependent upon the happening of apnea/hypopnea but not dependent upon the type of apnea , neither strictly upon desaturation .