What finding distinguishes diastolic heart failure?

Diastolic heart failure, also known as heart failure with preserved ejection fraction (HFpEF), is characterized by the heart's inability to properly fill with blood during the diastolic phase, despite having a normal or slightly reduced ejection fraction. In this condition, the ejection fraction is typically considered to be at least 50% or more, which distinguishes it from systolic heart failure, where the ejection fraction is reduced (often ≤ 40%).

In diastolic heart failure, the issue lies not in the heart's ability to contract effectively, but rather in its ability to relax and fill adequately. Thus, when identifying diastolic heart failure, the presence of a preserved ejection fraction is an essential criterion. This is why having an ejection fraction ≥ 50% clearly indicates the diagnosis of diastolic heart failure.

Other findings such as pulmonary congestion can occur in both types of heart failure and are not exclusive to diastolic heart failure. Right ventricular hypertrophy may also be found but does not specifically identify diastolic heart failure alone. Hence, the correct choice directly reflects the defining characteristic of the disorder.