Clinical Significance of Abnormal Relaxation Pattern of the Transmitral Flow Velocity Waveform in Older Patients With Preserved Left Ventricular Ejection Fraction

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Background: The pathophysiology of abnormal relaxation pattern in the transmitral flow (TMF) velocity waveform has not been fully elucidated. Methods and Results: A total of 173 patients who underwent comprehensive Doppler echocardiography and diagnostic cardiac catheterization for coronary artery disease were enrolled in the study. Peak early and late diastolic TMF velocities (E and A, respectively) were measured. Minimum left ventricular (LV) pressure; LV pre-A wave pressure (surrogate of mean left atrial [LA] pressure); time constant (τ) of LV pressure decay; and LV ejection fraction (LVEF) were calculated. Patients with E/A ratio <1.0 and LVEF ≥50% were enrolled. Patients with τ ≥48ms and those with τ <48ms were compared. The 2 groups had no significant differences in E or E/A. Minimum LV pressure (6.9±2.2mmHg vs. 3.6±2.9mmHg, P<0.0001) and LV pre-A wave pressure (9.5±2.4mmHg vs. 6.1±3.0mmHg, P<0.0001) were significantly higher in patients with τ ≥48ms compared to those with τ <48ms, but the difference between the LV pre-A and minimum LV pressures was similar between the groups (2.6±1.4mmHg vs. 2.5±1.5mmHg, P=0.89). Conclusions: Proportional elevations in minimum LV and pre-A pressures, due to deteriorated LV relaxation, resulted in no changes in the pressure gradient between the LA and LV in early diastole, E, or E/A.