What occurs during sudden cardiac arrest (SCA)?

Sudden cardiac arrest (SCA) is characterized by the abrupt cessation of cardiac function, meaning the heart stops beating unexpectedly and without prior warning. This condition typically results from an electrical malfunction in the heart that disrupts its normal rhythm, leading to an immediate loss of effective circulation and blood flow to vital organs.

In this scenario, the individual's heart may appear to be functioning normally right before the event, making the sudden onset particularly alarming. The outcome is usually fatal if not addressed immediately with interventions such as cardiopulmonary resuscitation (CPR) or defibrillation, emphasizing the critical need for swift action when SCA occurs.

While the other options mention various cardiac issues, they do not accurately describe the nature of sudden cardiac arrest. The weakening of the heart over time is indicative of heart failure rather than a sudden event, and irregularities or rhythm changes typically occur prior to or may lead to SCA but are not representative of the event itself.