Sudden cardiac arrest in an adult is most likely caused by what condition?

Sudden cardiac arrest in an adult is most frequently caused by ventricular fibrillation, which is a chaotic and ineffective heart rhythm. In this condition, the heart's electrical activity becomes disorganized, preventing it from pumping blood effectively. As a result, blood is not circulated to vital organs, leading to loss of consciousness and, if not treated promptly, death.

Ventricular fibrillation often develops as a consequence of other heart issues, particularly coronary artery disease, where narrowed arteries decrease blood flow to the heart muscle. When the muscle does not receive enough oxygen, it can become electrically unstable, culminating in ventricular fibrillation. This highlights why it is critical for individuals at risk of heart disease be aware of their condition and why early intervention, such as CPR and defibrillation, is vital for survival during an episode of cardiac arrest.

Understanding that ventricular fibrillation is a lethal arrhythmia that directly leads to cardiac arrest helps clarify its prominence as a primary cause of sudden cardiac events in adults.