From the Guidelines
Yes, obstructive sleep apnea (OSA) can cause bradycardia, which is an abnormally slow heart rate below 60 beats per minute. During an apnea episode, when breathing stops temporarily, the body's oxygen levels drop while carbon dioxide levels rise. This triggers a protective response called the diving reflex, where the vagus nerve is stimulated, causing the heart rate to slow down significantly. This bradycardia is particularly common during REM sleep in OSA patients. The severity of bradycardia often correlates with the severity of the sleep apnea, with some patients experiencing heart rates dropping below 30 beats per minute during apneic episodes.
Key Findings
- The 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1 highlights the importance of screening for sleep apnea in patients with nocturnal bradyarrhythmias.
- Treatment of the underlying OSA with continuous positive airway pressure (CPAP) therapy is usually effective in preventing these bradycardic episodes, with studies showing a reduction of 72% to 89% in episodes of profound sinus bradycardia, prolonged sinus pauses, and atrioventricular conduction block 1.
- The presence of undiagnosed sleep apnea may be high in patients referred for pacemaker implantation for asymptomatic bradycardia, and screening for sleep apnea is recommended in these patients 1.
Recommendations
- Screening for sleep apnea should be considered in patients with nocturnal bradyarrhythmias, as treatment of the underlying sleep apnea can effectively suppress these arrhythmias 1.
- CPAP therapy should be considered as a first-line treatment for OSA-related bradycardia, as it has been shown to be highly effective in preventing these bradycardic episodes 1.
- In severe cases where significant cardiac rhythm disturbances persist despite OSA treatment, additional cardiac evaluation may be necessary to determine if a pacemaker is required 1.
From the Research
OSA and Bradycardia
- Obstructive sleep apnea (OSA) may lead to heart rhythm abnormalities, including bradycardia, as stated in the study 2.
- A study found that OSA may be comorbid with and precipitate severe bradycardia, and CPAP therapy enabled rapid resolution of bradycardia in more than 80% of the cohort 2.
- The prevalence of bradycardia in patients with OSA was found to be 25% for daytime bradycardia and 69.8% for nocturnal bradycardia, according to a systematic review and meta-analysis 3.
Treatment of Bradycardia in OSA
- CPAP therapy was found to be effective in resolving bradycardia in patients with OSA, with a complete resolution of bradycardia and cardiac conduction abnormalities achieved in 11 out of 15 patients by day 4 of treatment 2.
- However, another study found that CPAP treatment did not significantly reduce the risk of daytime or nocturnal bradycardia compared to those without CPAP treatment 3.
- The protective effect of CPAP in patients with coronary artery disease and OSA without excessive sleepiness was modified by the pulse rate response to respiratory events, with patients with higher pulse rate response exhibiting greater cardiovascular benefit from CPAP therapy 4.
Clinical Implications
- OSA should be considered as a potential cause of bradycardia, and CPAP therapy may be an effective treatment option for patients with OSA and bradycardia 2, 3.
- A multidisciplinary approach to the management of CPAP therapy for OSA, including technical follow-up, management of comorbidities, and multimodal non-invasive monitoring, may be necessary to ensure optimal treatment outcomes 5.