Background and aim: We hypothesised that melatonin may represent a safe somniferous drug for cardiac patients, and assessed the effects of administering 5 mg of melatonin daily before bedtime for 30 days in patients with coronary artery disease (CAD) regarding changes in the nocturnal breathing pattern.
Methods: Sixty patients with CAD (aged 48-80 years) were randomised to melatonin/placebo treatment in a 2:1 ratio. A Holter ECG-based method (Lifescreen Apnea software) which has been validated as a screening tool for sleep-disordered breathing was used to estimate the apnoea/hypopnoea index (AHI). A 24-h Holter ECG was used to detect nocturnal breathing abnormalities at the beginning and at the end of the observation. The values of estimated AHI (eAHI) ≤ 15 were classified as optimal (Opt) and those 〉 15 - as pathological (Pat). A change of the breathing pattern was classified on the basis of the transition between the initial and final eAHI status (Opt→Opt; Opt→Pat; Pat→Pat, Pat→Opt). The mean initial and final value of eAHI and the percent of Opt and Pat values of eAHI in the initial and final assessment were compared between the melatonin and the placebo groups.
Results: The breathing pattern was not affected by melatonin - the mean initial value of the eAHI in the melatonin group was 18.2 ± 9.4, and in the placebo group 19.6 ± 12.3 (p = 0.64), whereas at the end of the observation in the melatonin group it increased by 1.2 ± 11.3, and in the placebo group - by 1.0 ± 9.0 (p = 0.44).
Conclusions: Hypnagogic treatment with melatonin did not worsen the eAHI in patients with CAD.