Reversible Left Ventricular Regional Non-Uniformity Quantified by Speckle-Tracking Displacement and Strain Imaging in Patients with Acute Pulmonary Embolism

Abstract

The aim of this study was to investigate the impact of acute right ventricular pressure overload (RVPO) on left ventricular (LV) function and regional uniformity using speckle-tracking displacement and strain analyses in patients with acute pulmonary embolism (PE). Twenty-five patients with acute PE (mean age, 59 ± 16 years) and 25 normal subjects were enrolled. Radial, longitudinal, and circumferential LV wall motion and myocardial deformation were analyzed using speckle-tracking displacement and strain imaging echocardiography, respectively, from the mid-LV short-axis and apical four-chamber views. The standard deviation of the heart rate-corrected intervals from QRS onset to peak systolic displacement (PSD) and peak systolic strain for the six segments was used to quantify LV systolic dyssynchrony. The standard deviation of regional PSD and peak systolic strain divided by their global values was used to quantify LV systolic heterogeneity. Mechanical discoordination of LV regional wall motion and myocardial deformation was assessed by averaging the frame-by-frame percentage discordance between segmental and global signal changes in the six segments. Patients with acute PE had reduced radial PSD and peak systolic strain and a large extent of displacement-derived nonuniformities (PSD dyssynchrony, 74 ± 32 vs 40 ± 20 m sec; PSD heterogeneity, 0.39 ± 0.13 vs 0.17 ± 0.08; and PSD discoordination, 23 ± 2% vs 15 ± 3%; P < .05 vs normal subjects for all comparisons) associated with a leftward shift of the interventricular septum. In contrast, all indices of strain-derived radial LV nonuniformities were not augmented by acute RVPO in patients with acute PE. Patients with acute PE also had impaired LV systolic function and regional uniformities in the longitudinal and circumferential directions. After the amelioration of acute RVPO by primary treatment, most of the indices of LV function and regional uniformity were restored to normal values. Multiple regression analysis indicated that only radial LV wall motion discoordination was a significant determinant of cardiac index. Acute RVPO induces reversal LV regional uniformities, which are closely associated with reduced LV function and abnormal geometry of the left ventricle, and radial LV wall motion coordination plays a key role in the short-term regulation of cardiac output in patients with acute PE.