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

The most common cause of cardiac arrest in adults is coronary artery disease. This condition occurs when the coronary arteries, which supply blood to the heart muscle, become narrowed or blocked due to the buildup of plaque composed of fat, cholesterol, and other substances. As blood flow is compromised, the heart may receive inadequate oxygen, leading to ischemia. If this progresses, it can result in dangerous arrhythmias such as ventricular fibrillation, ultimately culminating in cardiac arrest.

Coronary artery disease is prevalent due to various risk factors, including high blood pressure, high cholesterol levels, smoking, obesity, and a sedentary lifestyle. Its association with heart attacks, which can lead to sudden cardiac arrest, underscores its significance as the primary etiology in adults.

Other conditions listed, such as heart valve malfunction, respiratory failure, and severe allergic reactions, can contribute to cardiac arrest but are less common mechanisms. Instead, they may occur under specific circumstances or in patients with pre-existing conditions, making coronary artery disease the leading cause.