The Sleep Heart Health Study (SHHS) investigated the association between sleep-disordered breathing (SDB) and nocturnal cardiac arrhythmias. The study compared 228 subjects with SDB (Respiratory Disturbance Index ≥ 30) and 338 without SDB (RDI < 5). Results showed higher prevalence of atrial fibrillation, nonsustained ventricular tachycardia, and complex ventricular ectopy in the SDB group. After adjusting for confounders, 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 compared to those without SDB. A significant relationship was also observed between SDB and ventricular ectopic beats per hour. The study suggests that severe SDB is associated with increased risk of complex arrhythmias, even after adjusting for potential confounders. The findings highlight the importance of addressing SDB to reduce the risk of cardiac arrhythmias. The study's strengths include a large community-based sample, detailed covariate data, and rigorous data collection. Limitations include the use of a single bipolar lead for ECG analysis and the inability to evaluate intermediate thresholds of SDB. The study provides important clinical implications, suggesting that individuals with SDB may be at increased risk for nocturnal cardiac arrhythmias and sudden death. Further research is needed to quantify the population attributable risk of arrhythmias associated with SDB and to explore the potential for prevention or reversal through SDB treatment.The Sleep Heart Health Study (SHHS) investigated the association between sleep-disordered breathing (SDB) and nocturnal cardiac arrhythmias. The study compared 228 subjects with SDB (Respiratory Disturbance Index ≥ 30) and 338 without SDB (RDI < 5). Results showed higher prevalence of atrial fibrillation, nonsustained ventricular tachycardia, and complex ventricular ectopy in the SDB group. After adjusting for confounders, 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 compared to those without SDB. A significant relationship was also observed between SDB and ventricular ectopic beats per hour. The study suggests that severe SDB is associated with increased risk of complex arrhythmias, even after adjusting for potential confounders. The findings highlight the importance of addressing SDB to reduce the risk of cardiac arrhythmias. The study's strengths include a large community-based sample, detailed covariate data, and rigorous data collection. Limitations include the use of a single bipolar lead for ECG analysis and the inability to evaluate intermediate thresholds of SDB. The study provides important clinical implications, suggesting that individuals with SDB may be at increased risk for nocturnal cardiac arrhythmias and sudden death. Further research is needed to quantify the population attributable risk of arrhythmias associated with SDB and to explore the potential for prevention or reversal through SDB treatment.