A rare case of rapid eye movement sleep-related bradyarrhythmia syndrome with high-grade atrioventricular block: a case report.

Background: The relationship between sleep and arrhythmias is well established. Furthermore, the association between obstructive sleep apnoea (OSA) and bradyarrhythmias is well described. However, only a few cases of bradyarrhythmias observed during rapid eye movement (REM) sleep or REM sleep-related bradyarrhythmia syndrome, as it is known, have been documented in the literature.

Case summary: Here, we report another example of this syndrome. This was diagnosed during polysomnography in a middle-aged male and was independent of OSA. Several pauses, up to 5.7 s in duration, were observed during the study. A decision was made not to insert a pacemaker in this instance.

Discussion: The mechanism behind such bradyarrhythmias is not well established. However, features of autonomic lability were observed on the patient's electrocardiogram monitoring during stress testing. Such autonomic lability with vagal predominance may be the driver of the bradyarrhythmias. It is unknown whether they represent a benign incidental finding or not due to limited case numbers. Furthermore, there is currently no clear consensus on their management. This stresses the need for further research to confirm their pathophysiological basis and develop clearer management strategies.