Doppler echocardiography provides a good estimate of left-sided filling pressures using the transmitral flow pattern, the peak flow regurgitation flow velocity, the pulmonary venous flow pattern, and myocardial Doppler imaging. The transmitral flow, obtained in a four-chamber view, is directly related to the filling of the LV and is governed by the transmitral pressure gradient. The normal filling pattern is displayed as a biphasic tracing with an early and rapid-filling wave (E wave), followed by a diastasis period with minimal or no flow (Fig 1
). Finally, a late-filling wave (A wave) follows, caused by the atrial contraction. Both velocities of the respective flow waves and corresponding time velocity integrals are as important characteristics of LV filling.9 Another easily calculated parameter is the ratio of the peak flow velocities (ie, the ratio of E wave to A wave [E/A]). A normal flow velocity ratio is in the range of 0.75 to 1.40. The E/A ratio is strongly age-dependent. With increasing age, the E-wave velocity diminishes in favor of the late-filling A wave. It is important to remark that the various Doppler velocities are the resulting effect of several physiologic characteristics, such as LV compliance and relaxation, left atrial (LA) compliance, mitral valve area, and LA pressure (LAP). In addition, mechanical ventilation,23as well as external constraints (thrombi in the pericardial sac, stiffness of the pericardium, or high positive end-expiratory pressure ventilation with potential cardiac compression by the lungs) affects LV filling. Owing to these various interfering factors, it is conceivable that there is no correlation between the early filling velocity and the left-sided filling pressure (ie, LAP). As long as LAP is low in patients with dilated cardiomyopathy, the E-wave velocity, as well as the E/A ratio, will be low. With the progression of heart failure in these patients, the E-wave velocity will increase, and the E/A ratio will be > 1. The higher E-wave velocity will have a shorter deceleration time, reflecting decreased ventricular compliance, making an evolution toward a restrictive pattern (E > A),24 a very stiff LV with a rapid and important rise of ventricular pressures with small amounts of fluid.