In this episode, we review diastolic function and diastolic dysfunction. What are the four phases of diastole? What are the characteristics of normal diastolic filling patterns, and how do they change in mild, moderate, and severe diastolic dysfunction? How do the E and A waves on Doppler of mitral inflow evolve with increasing stages of diastolic dysfunction? How do E and A waves vary with age, preload, and heart rate? What does the L wave (mid-diastolic flow across the mitral valve) represent? How do the E/e' ratio on TDI of the basal segment of the lateral and septal walls evolve with increasing stages of diastolic dysfunction? When is it invalid to use E/e’ for estimating diastolic dysfunction? On PW Doppler of the pulmonary veins, why is S>D in mild diastolic dysfunction? Why does atrial reversal flow in the pulmonary vein increase in moderate and severe diastolic dysfunction? How can diastolic dysfunction be assessed in patients with atrial fibrillation? What additional findings are seen during a diastolic stress test? Tune in for answers to these questions.