What is the most common cause of cardiac arrest in adults?

The correct answer is myocardial infarction, as it is often the underlying cause that leads to ventricular fibrillation and subsequently to cardiac arrest. Myocardial infarctions, or heart attacks, occur when blood flow to a part of the heart is blocked, usually due to a clot in a coronary artery. This blockage causes damage to the heart muscle, which can lead to electrical disturbances, including ventricular fibrillation, where the heart quivers instead of pumping effectively.

While ventricular fibrillation is a critical rhythm that can directly lead to cardiac arrest, it is often a result of an initial event, such as a myocardial infarction. Understanding this relationship is crucial; without the initial cause like a heart attack, ventricular fibrillation would not occur as frequently.

Thus, knowing that myocardial infarction is the most common cause provides valuable insight into prevention and treatment strategies in emergency situations. It emphasizes the importance of recognizing and addressing the risk factors for heart disease and cardiac events in adults to help reduce the incidence of cardiac arrest.