What defines cardiac arrest?

Cardiac arrest is defined as the cessation of cardiac function, which means the heart has stopped pumping blood effectively. This condition is characterized by the absence of a detectable pulse and the cessation of breathing. Without prompt intervention, such as cardiopulmonary resuscitation (CPR) or defibrillation, it can quickly lead to death due to lack of blood flow to vital organs.

The other options do not correctly describe cardiac arrest. A heart murmur relates to abnormal heart sounds that can be due to a variety of reasons but does not indicate a failure of the heart to function. Severe chest pain with stable vitals suggests a condition where the heart is still functioning, even if there may be an issue present that requires attention. Rapid beating of the heart, or tachycardia, indicates increased heart activity and does not imply that the heart has stopped functioning altogether.