Doppler tissue imaging: A noninvasive technique for evaluation of left ventricular relaxation and estimation of filling pressures

Abstract

Objectives. This investigation was designed 1) to assess whether the early diastolic velocity of the mitral annulus (E(a)) obtained with Doppler tissue imaging (DTI) behaves as a preload-independent index of left ventricular (LV) relaxation; and 2) to evaluate the relation of the mitral E/E(a) ratio to LV filling pressures. Background. Recent observations suggest that E(a) is an index of LV relaxation that is loss influenced by LV filling pressures. Methods. One hundred twenty-five study subjects were classified into three groups according to mitral E/A ratio, LV ejection fraction (LVEF) and clinical symptoms: 34 asymptomatic subjects with a normal LVEF and an E/A ratio ≤1; 40 with a normal LVEF, an E/A ratio <1 and no heart failure symptoms (impaired relaxation [IR]); and 51 with heart failure symptoms and an E/A ratio >1 (pseudonormal [PN]). E(a) was derived from the lateral border of the annulus. A subset of 60 patients had invasive measurement of pulmonary capillary wedge pressure (PCWP) simultaneous with Doppler echocardiographic DTI. Results. E(a) was reduced in the IR and PN groups compared with the group of normal subjects: 5.8 ± 1.5 and 5.2 ± 1A vs. 12 ± 2.8 cm/s, respectively (p < 0.001). Mean PCWP (20 ± 8 mm Hg) related weakly to mitral E (r = 0.68) but not to E(a). The E/E(a) ratio related well to PCWP (r = 0.87; PCWP = 1.24 [E/E(a)] + 1.9), with a difference between Doppler and catheter measurements of 0.1 ± 3.8 mm Hg. Conclusions. E(a) behaves as a preload-independent index of LV relaxation. Mitral E velocity, corrected for the influence of relaxation (i.e., the E/E(a) ratio), relates well to mean PCWP and may be used to estimate LV filling pressures.