The Year in Echocardiography

Abstract

The reassessment and re-evaluation that have characterized echocardiographic research for the past 2 years have led to reaction and controversy in 2 areas of recent interest. First, the role of echo Doppler techniques in the evaluation of diastolic function, particularly the accuracy of the E/e= ratio in assessing left atrial pressure, has been questioned and has prompted study of the physiologic determinants of the tissue Doppler rapid filling wave. Second, there has been a flurry of response to the results of the PROSPECT (Predictors of Response to CRT) trial that questioned the value of echo Doppler indexes in defining left ventricular (LV) dyssynchrony (DYS) and predicting response to cardiac resynchronization therapy (CRT). In the area of valvular heart disease, 3-dimensional echo (3DE) studies have demonstrated mitral leaflet morphologic adaptation to chronic tethering and led to an understanding of the cellular mechanisms underlying these responses. New insights were also reported in a variety of other areas including the prognostic value of echo Doppler measures of LV function in the general population, the impact of contrast echo on clinical decision making in patients with technically difficult studies, 3-dimensional speckle tracking, and the utility of delayed diastolic relaxation following stress echo as a marker of prior ischemia. Diastolic FunctionThe E/e= ratio in predicting left atrial pressure: questions of accuracy. The E/e= ratio has been proposed as a reliable estimate of LV filling pressure because the E wave velocity depends on left atrial (LA) pressure, residual relaxation pressure, and age; e= is presumed to depend only on LV relaxation and age. Therefore, according to this theory, dividing E/e= should eliminate relaxation pressure and age and thus become a noninvasive estimate of LA pressure (1). However, several recent papers have raised questions about the reliability of tissue Doppler imaging (TDI) measures of LV relaxation as markers of LA pressure or diastolic function. Geske et al.(2) failed to show a significant correlation between simultaneous LA pressure and medial E/e= in a group of patients with hypertrophic cardiomyopathy (r 2 ϭ 0.07, p ϭ 0.07). Mullens et al. (3) found no significant correlation between pulmonary capillary wedge pressure (PCWP) and mitral e= in either the septal or lateral annulus or when averaged over both annular regions in a group of patients with advanced heart failure (r ϭ 0.18, p ϭ 0.07). Further, when patients were divided into those with E/e= ratios Ͻ8, 8 to 15, and Ͼ15, PCWPs were similar for each group (19 Ϯ 4 mm Hg, 19 Ϯ 7 mm Hg, and 20 Ϯ 6 mm Hg, respectively). Follow-up studies were obtained in 49% of patients and there was no correlation between absolute change in PCWP and change in mitral E/e= ratio and the investigators cautioned against the direct inference of such relationships in patients with significant LV systolic dysfunction, cardiac remodeling, or biventricular pacing (3). In an experimental study, Masutani et al. (4) reported that d...

Twist Mechanics of the Left Ventricle

“…However, the quality of tracking is dependent on the image quality and is vulnerable to dropouts of ultrasound data and reverberations. Moreover, clinical studies with speckle-tracking echocardiography have reported a wide variability in the values for resting LV systolic torsion (47). This may be related to the incongruent locations of LV apical and basal cross-sectional planes, errors related to through-plane motion, and the variable transmural depth of the region of interest for measuring LV rotation in each cross-sectional view.…”

Assessment of left ventricular torsion using speckle tracking echocardiography

“…Because this basal to apical cross-sectional plane rotational gradient does not change linearly, a more apical acquisition provides a larger counter-clockwise rotation, which heavily impacts the calculation of LV twist. Standardization of the level of short-axis acquisition is mandatory for the serial assessment of LV twist before and after interventions [16].…”