Wasserman A G, Meyer J F, Ross A M
Am Heart J. 1980 Oct;100(4):500-5. doi: 10.1016/0002-8703(80)90662-6.
Aortic wall echocardiograms were obtained simultaneously with pulmonary artery wedge pressures (PAWP) in 21 patients free of obstructive mitral valve disease. There was a significant (p < 0.001) negative correlation between the fraction of passive posterior aortic wall motion occurring in the first third of diastole (the atrial emptying index--AEI) and the pulmonary artery wedge pressure (r = -0.91). The AEI for patients with normal PAWP (less than or equal to 12 mm. Hg) was 0.94 +/- 0.06 (mean +/- S.D.) compared with 0.61 +/- 0.20 for those with abnormal PAWP (> 12 mm. Hg). No patient with a normal PAWP had an AEI < 0.80, and no patient with a PAWP > 18 mm. Hg had an AEI > 0.66. These data suggest that analogous to the reported use of the AEI to estimate severity of mitral obstruction, the index provides a noninvasive measure of left ventricular filling pressure when the mitral valve is normal.