Nocturnal arrhythmias and heart-rate swings in patients with obstructive sleep apnea syndrome treated with beta blockers

BACKGROUND: The higher cardiovascular variability and the increased prevalence of arrhythmias in patients with obstructive sleep apneas may contribute to their higher rate of fatal events during sleep. In this regard, the use of beta blockers (BB) is debated because they may induce bradyarrhythmias and alter the pattern of heart rate changes induced by apneas. Thus, the aim of our study is to quantify peri-apneic heart-rate swings and prevalence of nocturnal bradyarrhythmias in BB-treated and BB-naïve patients with obstructive sleep apnea. METHODS AND RESULTS: Our real-life, retrospective, cohort study analyzed data from patients with obstructive sleep apnea after a basal cardiorespiratory polysomnography. Among 228 eligible participants, we enrolled 78 BB-treated and 88 BBnaïve patients excluding those treated with antiarrhythmic drugs or pacemakers, or with uninterpretable ECG traces during polysomnography. In each patient, type and frequency of arrhythmias were identified and peri-apneic changes of RR intervals were evaluated for each apnea. BB-treated patients were older and with more comorbidities than BB-naïve patients, but had similar obstructive sleep apnea severity, similar frequency of arrhythmic episodes, and similar prevalence of bradyarrhythmias. Apnea-induced heart-rate swings, unadjusted for age, showed lower RR interval changes in BB-treated (133.5±63.8 ms) than BB-naïve patients (171.3±87.7 ms, P=0.01), lower RR interval increases during apneas (58.5±28.5 versus 74.6±40.2 ms, P=0.01), and lower RR interval decreases after apneas (75.0±42.4 versus 96.7±55.5 ms, P<0.05). CONCLUSIONS: BB appear to be safe in patients with obstructive sleep apnea because they are not associated with worse episodes of nocturnal bradyarrhythmias and even seem protective in terms of apnea-induced changes of heart rate.