What is the primary indicator of decompensated heart failure?

The primary indicator of decompensated heart failure is increased fluid retention leading to edema. In decompensated heart failure, the heart's ability to pump effectively is compromised, resulting in the kidneys experiencing reduced blood flow. This triggers a response where the kidneys retain sodium and water to compensate for perceived low blood volume, leading to fluid buildup in the body. This fluid retention manifests as edema, which is the swelling in tissues, particularly in the legs, ankles, and sometimes the abdomen.

Edema is a hallmark symptom that signals the worsening state of heart failure, as it directly results from the heart's failure to manage fluid status adequately. While symptoms such as dyspnea and tachycardia (increased heart rate) may accompany decompensated heart failure, they are secondary to the underlying issue of fluid overload. Thus, while other indicators can be present, edema specifically points to the failure of the circulatory system to maintain homeostasis in fluid management.