Which pattern of cardiac variability is commonly seen in patients with obstructive sleep apnea?

Which pattern of cardiac variability is commonly seen in patients with obstructive sleep apnea?

• A. Persistent tachycardia
• B. Persistent bradycardia
• C. Tachycardia alternating with bradycardia
• D. Prolong QT interval

Answer: (C)

Obstructive sleep apnea causes repeated cycles of airway collapse during sleep, leading to intermittent hypoxemia and arousals. These events provoke rapid shifts in the autonomic nervous system: the apneic/hypoxic phase triggers a surge in sympathetic activity and tachycardia, while the arousal and rebound ventilation increase vagal tone, which can slow the heart rate or cause brief pauses. Because these cycles recur many times each night, the heart rate tends to swing between faster and slower—tachycardia alternating with bradycardia. This pattern of alternating increases and decreases in heart rate is a classic finding in sleep apnea. A persistently high or persistently low heart rate isn’t typical for the nightly pattern, and prolongation of the QT interval isn’t the characteristic rhythm change caused by these autonomic swings.

Obstructive sleep apnea causes repeated cycles of airway collapse during sleep, leading to intermittent hypoxemia and arousals. These events provoke rapid shifts in the autonomic nervous system: the apneic/hypoxic phase triggers a surge in sympathetic activity and tachycardia, while the arousal and rebound ventilation increase vagal tone, which can slow the heart rate or cause brief pauses. Because these cycles recur many times each night, the heart rate tends to swing between faster and slower—tachycardia alternating with bradycardia. This pattern of alternating increases and decreases in heart rate is a classic finding in sleep apnea. A persistently high or persistently low heart rate isn’t typical for the nightly pattern, and prolongation of the QT interval isn’t the characteristic rhythm change caused by these autonomic swings.