MELATONIN LEVELS IN PATIENTS WITH ATRIAL FIBRILLATION – PILOT RESULTS.

Introduction: Atrial fibrillation is linked to atrial fibrosis, inflammation, and oxidative stress. To date, the sleep hormone melatonin has not been explicitly associated with atrial fibrillation, despite its recognized antioxidant, anti-fibrotic, and anti-inflammatory properties. A recent study conducted on mice in 2022 demonstrated that melatonin plays a role in partially inhibiting the aforementioned processes involved in the development of atrial fibrillation. However, the endogenous levels of melatonin in patients with atrial fibrillation remain undescribed in the existing literature. The present study aims to investigate the melatonin profiles of patients with atrial fibrillation and to compare these profiles with those of healthy control subjects.

Methods: Saliva samples were collected within a 24-hour period according to a predetermined schedule (10:00, 13:00, 16:00, 19:00, 22:00, 01:00, 04:00, 07:00, 10:00) using specially marked tubes and adhering to strict protocol measures. Following collection, the samples were frozen and subsequently transported to the laboratory for analysis via radioimmunoassay. After measurement, the melatonin levels were statistically evaluated.

Results: In the pilot group of patients (n = 13) and controls (n = 10), melatonin concentrations were found to be reduced in patients with atrial fibrillation compared to controls. Additionally, patients with atrial fibrillation exhibited a lower amplitude of melatonin production. 

Conclusion: Atrial fibrillation has been associated with decreased levels of melatonin in a pilot cohort of patients. Melatonin may serve as a protective factor against fibrotic changes and might play a role in mitigating inflammatory and oxidative processes.

Supported by CarDia and EXCELES, No. LX22NPO5104 and MUQUABIS GA no. 101070546.