Novel echocardiographic method to assess left ventricular chamber stiffness and elevated end-diastolic pressure based on time–velocity integral measurements of pulmonary venous and transmitral flows

The detection of increased left ventricular (LV) chamber stiffness may play an important role in assessing cardiac patients with potential but not overt heart failure. A non-invasive method to estimate it is not established. We investigated whether the echocardiographic backward/forward flow volume ratio from the left atrium (LA) during atrial contraction reflects the LV chamber stiffness.

We studied 62 patients who underwent cardiac catheterization and measured their left ventricular end-diastolic pressure (LVEDP) and pressure increase during atrial contraction (ΔPa) from the LV pressure waveform. Using the echocardiographic biplane method of disks, we measured the LV volume change during atrial contraction indexed to the body surface area (ΔVa), and ΔPa/ΔVa was calculated as a standard for the LV operating chamber stiffness. Using pulsed Doppler echocardiography, we measured the time–velocity integral (TVI) of the backward pulmonary venous (PV) flow during atrial contraction (I_PVA) and the ratio of I_PVA to the PV flow TVI throughout a cardiac cycle (F_PVA). We also measured the TVI of the atrial systolic forward transmitral flow (I_A) and the ratio of the I_A to the transmitral TVI during a cardiac cycle (F_A) and calculated I_PVA/I_A and F_PVA/F_A. I_PVA/I_A and F_PVA/F_A were well correlated with ΔPa/ΔVa (r = 0.79 and r = 0.81) and LVEDP (r = 0.73 and r = 0.77). The areas under the ROC curve to discriminate LVEDP >18 mmHg were 0.90 for I_PVA/I_A and 0.93 for F_PVA/F_A.

The F_PVA/F_A, the backward/forward flow volume ratio from the LA during atrial contraction, is useful for non-invasive assessments of LV chamber stiffness and elevated LVEDP.