Final answer:
Cardiac arrest is a more serious and immediately life-threatening condition than heart failure.
Step-by-step explanation:
Cardiac arrest is generally a more serious and immediately life-threatening condition than heart failure. Cardiac arrest occurs when the heart stops pumping blood or pumps blood so poorly that vital organs cannot function. It is a medical emergency that requires immediate intervention to prevent death. On the other hand, heart failure is a chronic condition in which the heart is unable to pump blood effectively. Although heart failure can be life-threatening if left untreated, it is generally not as immediately life-threatening as cardiac arrest.