The Sleep Heart Health Study (SHHS) investigated the association between sleep-disordered breathing (SDB) and nocturnal cardiac arrhythmias. The study compared two groups: 228 subjects with SDB (respiratory disturbance index ≥ 30) and 338 subjects without SDB (respiratory disturbance index < 5). The prevalence of atrial fibrillation, nonsustained ventricular tachycardia, and complex ventricular ectopy was significantly higher in the SDB group compared to the non-SDB group. After adjusting for age, sex, BMI, and coronary heart disease, individuals with SDB had four times the odds of atrial fibrillation, three times the odds of nonsustained ventricular tachycardia, and almost twice the odds of complex ventricular ectopy. The study also found a significant age interaction, indicating that the association between SDB and complex ventricular ectopy was stronger in younger individuals. These findings suggest that individuals with severe SDB are at a higher risk of developing complex arrhythmias, which may contribute to the increased incidence of sudden nocturnal death observed in sleep apnea.The Sleep Heart Health Study (SHHS) investigated the association between sleep-disordered breathing (SDB) and nocturnal cardiac arrhythmias. The study compared two groups: 228 subjects with SDB (respiratory disturbance index ≥ 30) and 338 subjects without SDB (respiratory disturbance index < 5). The prevalence of atrial fibrillation, nonsustained ventricular tachycardia, and complex ventricular ectopy was significantly higher in the SDB group compared to the non-SDB group. After adjusting for age, sex, BMI, and coronary heart disease, individuals with SDB had four times the odds of atrial fibrillation, three times the odds of nonsustained ventricular tachycardia, and almost twice the odds of complex ventricular ectopy. The study also found a significant age interaction, indicating that the association between SDB and complex ventricular ectopy was stronger in younger individuals. These findings suggest that individuals with severe SDB are at a higher risk of developing complex arrhythmias, which may contribute to the increased incidence of sudden nocturnal death observed in sleep apnea.