BackgroundSubjects in sinus rhythm have two distinct diastolic flow velocities in the left ventricular (LV) outflow tract directed toward the aortic valve. These follow E and A waves of the transmitral flow and are referred to as Er and Ar waves, respectively. The A wave transit time from the mitral valve to the LV outflow tract is shorter than that of the E wave and is shorter in those with LV hypertrophy and the aged, suggesting its possible dependence on LV late diastolic stiffness.Methods and ResultsWe measured the peak-to-peak and onset-to-onset A wave transit times from the mitral valve to the LV outflow tract (AArpand AAr, intervals, respectively) using Doppler echocardiography in 20 patients undergoing left heart catheterization for evaluation of coronary artery disease. These intervals were correlated with indices of LV late diastolic stiffness obtained from high-fidelity LV pressure tracings and angiographic volume assessments. The AArp and AAr. intervals correlated significantly with LV Dp/DV (conventionally dP/dV) (r= − .68 and − .83, respectively), volume stiffness, V Dp/DV (r= − .74 and − .80, respectively) and LV (V/P) (Dp/DV) (r= − .69 and − .74, respectively). The AAr. interval correlated better with the square roots of LV Dp/DV and volume stiffness (r= − .86 and − .87, respectively).ConclusionsWe conclude that AArp and AAr. intervals are easily obtainable Doppler parameters that reflect LV late diastolic stiffness in natients with coronary artery disease and possibly in other patient groups.