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

Ventricular fibrillation is often regarded as the most common cause of cardiac arrest in adults because it is a specific arrhythmia that leads to an ineffective heartbeat and is typically a consequence of underlying heart disease, such as myocardial infarction. When the heart is in ventricular fibrillation, it quivers instead of pumping blood, resulting in the cessation of effective circulation and causing the individual to lose consciousness quickly.

While myocardial infarction can be a leading cause of spontaneous cardiac arrest due to its role in triggering dangerous arrhythmias like ventricular fibrillation, the direct mechanism of cardiac arrest happening due to the heart's inability to maintain a rhythm is more accurately described by ventricular fibrillation. It is important to recognize that ventricular fibrillation often follows conditions like heart attacks, making it a critical focus during resuscitation efforts.

The other options refer to conditions that may contribute to cardiac arrest, but they do not represent the immediate mechanism through which cardiac arrest most often occurs in adults. Pulmonary embolism can lead to cardiac arrest, though it is less common as a direct cause than ventricular fibrillation. Arrhythmias resulting from electrolyte imbalances can also lead to cardiac issues, but they are less frequent triggers compared to the scenario of ventricular fibrillation arising from heart