Final answer:
Swelling of ankles and feet is a symptom of heart failure, caused by fluid buildup due to poor circulation and exacerbated by a lack of physical activity, which impairs the skeletal muscle pump.
Step-by-step explanation:
Swelling of ankles and feet in the context of heart failure is a symptom. This symptom, known medically as edema, is the result of fluid buildup in the tissues due to the heart's decreased ability to pump blood effectively. The skeletal muscle pump refers to the role that muscle contractions play in assisting the return of blood from the extremities to the heart.
In an obese patient who is sedentary and stands all day, such as the one described, edema can become more pronounced due to the lack of muscle contractions that would normally help push blood back up to the heart, coupled with the increased pressure from prolonged standing. Therefore, understanding the physiology of the skeletal muscle pump and its relevance to fluid dynamics in the body can help in diagnosing and managing the underlying causes of heart failure and its symptoms.