Night-time bradyarrhythmia in a patient with mild obstructive sleep apnea syndrome is reversed with CPAP treatment.

Nocturnal cardiac arrhythmia is a common clinical feature of obstructive sleep apnea syndrome. Pathologically relevant rhythm disturbances such as atrioventricular block or ventricular tachycardia are known to occur mainly in patients with a high apnea-hypopnea index and marked oxygen desaturation. We report on a patient with mild obstructive sleep apnea syndrome who nevertheless showed intermittent second-degree atrioventricular block during stages of rapid eye movement sleep-associated hypopneas. Cardiac arrhythmia was reversed with the initiation of nasal continuous positive airway pressure treatment. Based on this case report and taking into account known facts from the literature, the finding of intermittent second-degree atrioventricular block in our patient with mild obstructive sleep apnea syndrome supports careful evaluation of electrocardiogram recording acquired during polysomnography in all patients with suspected obstructive sleep apnea syndrome.