In hypothermia, why is the myocardium prone to dysrhythmias?

In hypothermia, why is the myocardium prone to dysrhythmias?

• A. Cold myocardium increases risk of dysrhythmias
• B. Hyperkalemia
• C. Increased conduction velocity
• D. Increased oxygen demand

Answer: (D)

In hypothermia the heart becomes more prone to rhythm disturbances primarily because the body’s demand for oxygen rises when shivering and the stress response are active. Shivering dramatically increases metabolic rate, boosting myocardial oxygen consumption. If the oxygen supply cant keep up—due to cold-induced changes in perfusion or other stressors—the myocardium becomes ischemic and electrically irritable, making dysrhythmias more likely. Cold temperatures also alter conduction and ion balance, but the key link here is the mismatch between higher oxygen demand and limited supply.

In hypothermia the heart becomes more prone to rhythm disturbances primarily because the body’s demand for oxygen rises when shivering and the stress response are active. Shivering dramatically increases metabolic rate, boosting myocardial oxygen consumption. If the oxygen supply cant keep up—due to cold-induced changes in perfusion or other stressors—the myocardium becomes ischemic and electrically irritable, making dysrhythmias more likely. Cold temperatures also alter conduction and ion balance, but the key link here is the mismatch between higher oxygen demand and limited supply.