How can low oxygen contribute to arrhythmias?

How can low oxygen contribute to arrhythmias?

• A. It increases the heart rate through enhanced sympathetic activity.
• B. It can cause automaticity foci to become irritable, leading to premature beats.
• C. It inhibits junctional rhythms, preventing escape beats.
• D. It has no effect on cardiac rhythm.

Answer: (B)

Low oxygen levels in the body, a condition known as hypoxia, have a significant impact on cardiac function and can lead to arrhythmias. One of the primary mechanisms by which low oxygen affects the heart is through the irritation of automaticity foci, which are areas within the heart that can initiate electrical impulses independently of the sinoatrial (SA) node.

When oxygen delivery to cardiac tissues is compromised, these automaticity foci may become more irritable, leading them to fire off improperly or too frequently. This can result in the generation of premature beats—extra heartbeats that occur before the regular heartbeat. The increased irritability is often due to altered ionic balances in the cardiac cells, which disrupt normal electrical conduction and timing within the heart.

Understanding this phenomenon is crucial for recognizing how disruptions in oxygen levels translate into specific types of heart rhythm issues.