A 45-year-old obese man reports excessive daytime sleepiness, morning headaches, and his wife reports loud snoring with observed apnoeas. Polysomnography confirms obstructive sleep apnea (OSA). Which of the following cardiovascular consequences is MOST strongly and causally linked to untreated severe OSA?

• A Ventricular fibrillation as the primary arrhythmia
• B Complete heart block due to vagal overactivity during apnoeic episodes
• C Systemic hypertension (resistant/nocturnal) due to intermittent hypoxia-driven sympathetic activation ✓
• D Left atrial enlargement due to tricuspid regurgitation

Explanation

Obstructive sleep apnoea causes cyclical intermittent hypoxia, hypercapnia, and intrathoracic pressure changes. Each apnoeic episode triggers sympathetic surges (chemoreflex-mediated), causing acute BP rises and eventually sustained systemic hypertension. OSA is the most common cause of secondary/resistant hypertension. CPAP treatment improves nocturnal BP significantly. OSA also increases risk of AF, stroke, and pulmonary hypertension, but systemic hypertension (especially nocturnal, non-dipping pattern) is the most strongly documented cardiovascular consequence.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.