What percentage is considered depressed ejection fraction in systolic heart failure?

In the context of systolic heart failure, a depressed ejection fraction is typically characterized by a measurement of less than 40%. The ejection fraction (EF) is a vital metric that indicates the percentage of blood that is pumped out of the heart with each contraction.

When the ejection fraction falls below this threshold, it suggests that the heart is not functioning effectively, resulting in reduced cardiac output and symptoms associated with heart failure. A percentage below 40% is often used in clinical practice and research as a hallmark of systolic dysfunction, leading to a classification of heart failure as "reduced ejection fraction" (HFrEF).

In contrast, values above 40% would generally indicate a better-preserved function of the heart. Specifically, ejection fractions between 40-50% may still suggest mild systolic dysfunction, while numbers exceeding 50% indicate a more normal cardiac function.