Severity of nocturnal cardiac arrhythmias correlates with intensity of sleep apnea in men.

Various cardiac arrhythmias frequently occur in patients with sleep apnea, but complex analysis of the relationship between their severity and the probable arrhythmogenic risk factors is conflicting. The question is what cardiovascular risk factors and how strongly they are associated with the severity of cardiac arrhythmias in sleep apnea. Adult males (33 with and 16 without sleep apnea), matched for cardiovascular co-morbidity were studied by polysomnography with simultaneous ECG monitoring. Arrhythmia severity was evaluated for each subject by a special 7-degree scoring system. Laboratory, clinical, echocardiographic, carotid ultrasonographic, ambulatory blood pressure, and baroreflex sensitivity values were also assessed. Moderate sleep apnea patients had benign, but more exaggerated cardiac arrhythmias than control subjects (2.53 ± 2.49 vs. 1.13 ± 1.64 degrees of cumulative severity, p < 0.05). We confirmed strong correlations between the arrhythmia severity and known arrhythmogenic risk factors (left ventricular ejection fraction and dimensions, right ventricular diameter, baroreflex sensitivity, carotid intima-media thickness, age, previous myocardial infarction, and also apnea-hypopnea index). In multivariate modelling only the apnea-hypopnea index indicating the sleep apnea intensity remained highly significantly correlated with the cumulative arrhythmia severity (beta = 0.548, p < 0.005). In conclusion, sleep apnea modifying cardiovascular risk factors and structures or functions provoked various nocturnal arrhythmias. The proposed scoring system allowed a complex analysis of the contribution of various triggers to arrhythmogenesis and confirmed the apnea-hypopnea index as an independent risk for nocturnal cardiac arrhythmia severity in sleep apnea.