10 Sep Obstructive Sleep Apnoea and Cardiac Implications
Obstructive sleep apnoea (OSA) is a common condition where the airway becomes partially or completely blocked during sleep, leading to breathing pauses and reduced oxygen levels.
Approximately 1 in 5 adults has or will develop mild OSA (AHI 5-15), with 1 in 15 having moderate (AHI 15-30). These repetitive apnoeic events have been linked to disturbances in multiple physiological systems, namely the cardiovascular system. This disruption can cause various health issues, including problems with the heart’s rhythm.
How OSA Affects Heart Rhythm
During episodes of OSA, the body experiences a drop in oxygen levels and an increase in carbon dioxide. These changes stimulate the sympathetic nervous system—the body’s “fight or flight” response—leading to increased heart rate and blood pressure. Additionally, the effort to breathe against a blocked airway creates negative pressure in the chest, which can strain the heart. Over time, these factors may contribute to the development of arrhythmias or otherwise irregular heartbeats.
Atrial fibrillation (AF), a condition where the heart’s upper chambers beat irregularly, is commonly associated with OSA. The structural changes in the heart, such as atrial dilation and fibrosis, can serve as a substrate for AF. Studies have shown that treating OSA with continuous positive airway pressure (CPAP) therapy can reduce the recurrence of AF after procedures like electrical cardioversion and catheter ablation.
Risks Beyond Arrhythmias
OSA is also linked to an increased risk of sudden cardiac death (SCD). Nocturnal hypoxemia, a hallmark of OSA, has been identified as an independent predictor of SCD, even when accounting for other cardiovascular risk factors. This underscores the importance of managing OSA to mitigate its impact on heart health.
Importance of Diagnosis and Treatment
Given the significant association between OSA and cardiac rhythm disorders, it’s crucial for individuals with OSA to be evaluated for potential heart issues. Early diagnosis and appropriate treatment, such as CPAP therapy, can help manage both OSA and its cardiovascular complications, improving overall health outcomes.
Summary
OSA can often be underestimated and labelled as “just a sleep disorder”, however, it is definitely better described as a condition that can have serious implications for heart health. Understanding the relationship between OSA and cardiac rhythm disorders is essential for effective management, prevention of associated risks and an overall healthier lifestyle. Especially given sleep study technology has improved greatly with both home based and in-lab studies available, with the former covered under Medicare.
References
Geovanini, G. R., & Lorenzi-Filho, G. (2018). Cardiac rhythm disorders in obstructive sleep apnea. Journal of thoracic disease, 10(Suppl 34), S4221–S4230. https://doi.org/10.21037/jtd.2018.12.63