Which type of heart failure is characterized by decreased ejection fraction and an S3 gallop?

Systolic heart failure is characterized by the heart's inability to contract effectively, leading to a decreased ejection fraction. This reduction in ejection fraction indicates that the heart is not pumping blood efficiently with each heartbeat. An S3 gallop, often referred to as a "ventricular gallop," is another hallmark of this condition and is associated with increased volume overload in the ventricles. It typically occurs during rapid filling of the ventricles in early diastole, which is a reflection of the underlying hemodynamic changes associated with systolic dysfunction.

In contrast, diastolic heart failure primarily involves issues with the heart's ability to fill properly during diastole and usually has a preserved ejection fraction, hence it wouldn’t present with an S3 gallop. High-output heart failure is characterized by the heart meeting the body's high demand for blood flow, and while it can cause heart failure symptoms, the ejection fraction is typically normal or high due to the increased cardiac output. Chronic heart failure can encompass both systolic and diastolic dysfunction, but it is not specific enough to indicate decreased ejection fraction and the presence of an S3 gallop.

Thus, systolic heart failure is the most accurate choice given its specific association