Obstructive Sleep Apnea and Syncope

Pathophysiological Mechanisms

OSA is characterized by repetitive episodes of complete or partial upper airway obstruction during sleep, while respiratory efforts continue, according to the American Thoracic Society 1
Marked swings in intrathoracic pressure occur during obstructive events, as reported by the American Academy of Sleep Medicine 2

OSA can induce various arrhythmias that may cause syncope, including bradyarrhythmias, atrial fibrillation, and ventricular arrhythmias, as noted by the American Geriatrics Society 3
Long-term OSA leads to cardiovascular adaptations that increase syncope risk, such as arterial hypertension and heart failure, according to the American Geriatrics Society 4

Elderly patients are particularly vulnerable to OSA-related syncope due to higher prevalence of OSA, age-related changes in cardiovascular function, and comorbid conditions, as reported by the American Geriatrics Society 3
Syncope in patients with suspected OSA warrants evaluation with polysomnography (PSG) to confirm OSA diagnosis, as recommended by the American Academy of Sleep Medicine 5
Assessment of oxygen desaturation index (ODI) and apnea-hypopnea index (AHI) is necessary for diagnosing OSA, according to Sleep Medicine Reviews 6

OSA-related syncope may be misdiagnosed as other forms of syncope or seizures, as noted by the American Geriatrics Society 3
The presence of OSA should be considered in patients with unexplained syncope, especially those with cardiovascular risk factors, as reported by the American Geriatrics Society 4