This video is part 4 in a series on Heart Failure - Diastolic Dysfunction. Stage 1 diastolic dysfunction is indicated by an echocardiogram showing an inverted E/A wave ratio (less than 1). The E wave shows the rate of flow past the mitral valve ring during diastole-filling the ventricle. Usually, the majority of filling occurs in the E wave period ( Early diastole). The A wave (atrial kick) happens at the end of the diastole. It usually adds about 20% of the volume. But the if ventricles are stiff ( hypertension is the most common cause), they don't relax well. The filling during Early diastole is decreased. Since there is a lot of volume remaining in the atria during the late (A wave) phase, the Atrial kick is increased in early-stage diastolic dysfunction.