What sign may indicate a worsening of heart failure in a patient?

A weight gain of more than 2 pounds in a day can indicate a worsening of heart failure because it often suggests fluid retention, which is a common issue in patients with heart failure. When the heart is unable to pump effectively, it can lead to an accumulation of fluids in the body, particularly in the lungs and extremities. This sudden weight gain is a red flag for healthcare providers, as it can signify that the patient may be experiencing an exacerbation of heart failure, requiring closer monitoring and potential intervention to prevent further complications.

The other options do not present the same level of concern. A decrease in appetite can occur for various reasons and is not as direct an indicator of worsening heart failure as rapid weight gain. Increased activity tolerance may indicate improvement in the patient's condition rather than a worsening. Stable blood pressure suggests that there is no acute change in the cardiovascular status of the patient, which is inconsistent with the progression of heart failure.