Left ventricular torsional parameters in patients with non-ischemic dilated cardiomyopathy

Abstract

Background: Velocity vector imaging (VVI) is a new echocardiography method to assess myocardial deformation in two dimensions. Objectives: In this study, we used VVI to evaluate left ventricular (LV) main torsional parameters in non-ischemic dilated cardiomyopathy (DCM) patients in compared with normal subjects. Patients and Methods: Twenty-six DCM patients and Twenty-four normal subjects were assessed. Echocardiographic images of the short axis apical and basal views of LV were processed by VVI software to measure peak rotation degrees and also peak rotation rates in systole. LV twist was well-defined as the net difference between apical and basal rotation values and also LV torsion was considered as LV twist divided by left ventricular diastolic longitudinal length. In addition, peak untwisting value and untwisting rate were measured in diastole too. Results: LV twist value (5.54 ± 1.94° in DCM VS. 11.5 ± 2.45° in control group) and also LV torsion (0.71 ± 0.28°/cm in DCM VS. 1.53 ± 0.42°/cm in control group) were significantly decreased in DCM patients compared with normal group (P < 0.001 for both); also, the twisting rate was notably lower in DCM vs. control (38.68 ± 14.43°/s in DCM vs. 75.88 ± 17.25°/s in control; P < 0.001) and also untwisting rate (36.28 ± 13.48°/s in DCM vs. -73.79 ± 24.45°/s in control; P < 0.001), However normalization of these times for systolic duration or LV length creates different values. Conclusions: LV twist, torsion and untwist and also rate of them are significantly impaired in DCM and this impairment is well-related to LV global systolic and diastolic dysfunction. VVI is a new noninvasive technique that can be used to evaluate LV torsional parameters.