Aortic valve replacement (AVR) is indicated for patients with severe aortic stenosis (AS) associated with either symptoms or left ventricular (LV) dysfunction. Severe AS is generally defined as an aortic valve area ≤1.0 cm and a mean transvalvular gradient of ≥40 mm Hg. However, many patients with symptomatic and severe AS may have lower gradients resulting from LV systolic dysfunction (so-called low flow [LF], low ejection fraction [LEF]), high afterload with pronounced LV concentric remodeling (paradoxical LF, normal ejection fraction [NEF]), and from errors or assumptions inherent in the measurement of gradient and valve area. These patients have a prognosis similar to or worse than that for patients with classic AS, both with and without surgery. However, little is known about the prognostic value of LF independently of gradient and EF and its treatment.