Doppler echocardiography is useful in assessing diastolic dysfunction. Pulsed-wave Doppler echocardiographic interrogation of the atrioventricular valves and the central veins has been used in conjunction with respiratory monitoring to characterize abnormal diastolic function of the heart in diseases such as constrictive pericarditis, restrictive cardiomyopathy, and cardiac tamponade. Constrictive pericarditis has distinct Doppler flows with marked respiratory variation because the pericardial shell separates the intracardiac pressures from intrathoracic pressure. This is not the case with restrictive cardiomyopathy, as in cardiac amyloidosis. Cardiac amyloidosis shows a spectrum of the Doppler flows which evolve as the disease progresses from abnormal relaxation in the early phase to pseudo-normal in the intermediate phase and to restrictive in the advanced phase. Doppler echocardiography can be used to assess the hemodynamic significance of pericardial effusion and to detect cardiac tamponade.