What is a common indicator of worsening heart function in children?

Unexplained irritability and decreased appetite are important indicators of worsening heart function in children. In cases of heart dysfunction, children often experience fatigue and malaise due to inadequate blood flow and oxygenation. This can manifest as irritability, as the child may feel unwell or uncomfortable. Decreased appetite is also commonly observed because the body may prioritize vital functions over digestion when it is under stress, such as in heart failure scenarios. This combination of behavioral changes can be a red flag for caregivers and healthcare providers, signaling that the child's cardiac condition may be deteriorating and requiring further evaluation and management.

The other options mentioned do not align with the common signs of worsening heart function. Increased activity levels may suggest a child is feeling better or more energetic, and improvement in sleep quality is typically not associated with cardiac decline. Weight gain can also be misleading; in some contexts, it might indicate fluid retention, but it does not directly reflect worsening heart function in the child. Therefore, both behavioral changes like irritability and reduced appetite serve as critical signs to monitor for potential deterioration in cardiac health.