In the context of heart failure, which symptom is associated with increased pulmonary capillary pressure while lying down?

Orthopnea is characterized by difficulty breathing when lying flat, which is directly associated with increased pulmonary capillary pressure. In patients with heart failure, lying down can exacerbate the problem because the redistribution of blood volume increases venous return to the heart, which in turn raises the pressure in the pulmonary capillaries. This elevated pressure can lead to pulmonary congestion, making it hard for the patient to breathe when they are horizontal.

Patients often seek relief by sleeping in an upright position or using multiple pillows, which helps reduce the venous return and subsequently the pulmonary capillary pressure, allowing for easier breathing. The other options, while relevant to heart failure, do not specifically pertain to the symptoms caused by changes in pulmonary capillary pressure in a supine position. Chronic fatigue, peripheral edema, and bradycardia represent different aspects or complications of heart failure that do not directly correlate with positing changes in pulmonary symptoms.