Objective: Assess the diagnostic contribution of cyclic nocturnal variations in heart rate in sleep apnea syndrome.
Patients and methods: Holter recordings performed in a population of 30 patients with massive obesity defined as a body mass index greater than 40 kg/m2 and sleep apnea syndrome defined by an apnea index greater than 5 apneas per hour were analyzed retrospectively. The control group was composed of 15 patients with massive obesity but without sleep apnea syndrome. High variability in nocturnal heart rate was assessed using a visual criterion defined as repeated episodes of progressive reduction in heart rate followed by a sudden acceleration reaching a difference of 30 bpm between the highest and lowest heart rate and occurring at least 5 times during one consecutive hour of recording.
Results: Increased nocturnal variability in heart rate was evidenced in all the patients with sleep apnea syndrome (30/30) but was not observed in any of the control subjects (0/15).
Conclusion: These results suggest that Holter recordings can be a useful tool for the diagnosis of sleep apnea syndrome.