REM Sleep–Associated Asystole

BACKGROUND: Rapid eye movement (REM) sleep-associated bradyarrhythmia syndrome is characterized by asystole or complete heart block during the REM phases of sleep. There are minimal reported cases in the literature. CASE SUMMARY: This is a case of REM-associated sinus pauses incidentally noted on a sleep study in a young, healthy patient. Despite an implantable loop recorder demonstrating continued nocturnal pauses of up to 9.5 seconds, the patient remained without daytime symptoms or pauses and was managed without a pacemaker. DISCUSSION: REM sleep-associated bradyarrhythmia syndrome is a rarely described and poorly understood phenomenon with minimal guidelines for management. It may be underreported given that it is often asymptomatic and incidentally noted on sleep studies. Close surveillance may be appropriate rather than pacemaker implantation in those patients who are without daytime symptoms.