Cardiac arrhythmias are often accompanied by sleep-disordered breathing, say German researchers.
Thomas Bitter, from the Ruhr University in Bochum, used cardiorespiratory polygraphy to investigate whether 150 patients with atrial fibrillation, which included 110 men and 40 women, suffered from sleep-disordered breathing.
Only patients with normal systolic left ventricular function were included in the study, in order to avoid statistical bias.
Bitter and his colleagues observed that breathing during sleep was impaired in 74 per cent of the patients.
The researchers said that 43 per cent of the group suffered from obstructive sleep apnea (OSA), which means that the upper respiratory tract is constricted during the night, leading to oxygen deficiency.
According to the authors, 31 per cent of the patients suffered from central sleep apnea (CSA), a type of disorder characterized by periodic decreases and increases in the respiratory depth and rate.
Breathing becomes flatter and flatter, until it is interrupted for an interval.
Awareness of OSA already plays an important role in the primary and secondary prevention of atrial fibrillation.
The researchers say that their observations suggest that central sleep apnea is also relevant.
The study has been published in the journal Deutsches Arzteblatt International.