Which of the following is an expected outcome in patients with heart failure?

Fluid retention is indeed an expected outcome in patients with heart failure due to the heart's reduced capacity to pump blood effectively. As heart failure progresses, the body compensates by activating several neurohormonal systems, including the renin-angiotensin-aldosterone system. This leads to increased sodium and water retention in an effort to maintain adequate blood volume and pressure. However, this compensatory mechanism can ultimately result in excess fluid accumulation in tissues, known as edema, as well as congestion in the lungs and other organs.

In contrast, increased energy levels, decreased respiratory rate, and improved kidney function do not typically occur in heart failure patients. Instead, these individuals often experience fatigue and weakness due to decreased cardiac output. Additionally, respiratory rates may increase as the body struggles to receive enough oxygen, particularly if pulmonary congestion is present. Kidney function may also decline in heart failure due to reduced renal perfusion, further complicating fluid balance. Thus, fluid retention stands out as a hallmark symptom closely associated with the condition.