Aims: Different layers of myocardium may contribute differently to myocardial deformation. Speckle tracking based on high resolution two-dimensional (2D) echocardiography has been used to define myocardial deformation parameters of whole left ventricular (LV) segments. This study evaluated with a Novell analysis modality allowing layer-specific analysis of deformation if there are differences in myocardial deformation between different layers of myocardium.
Methods and results: In 30 normal subjects and 20 patients with impaired myocardial function 2D parasternal short-axis echocardiographic views of the LV were acquired at the basal, mid-papillary, and apical levels. Using a Novell automatic frame-to-frame tracking system of natural acoustic echocardiographic markers (EchoPAC, GE Ultrasound, Haifa, Israel), circumferential strain (CS) and strain rate of the endocardial, mid-myocardial and epicardial layer was calculated for each LV segment in an 18-segment model. Wall motion for each segment was defined as normokinetic, hypokinetic, and akinetic based on 2D echocardiographic images. Peak systolic CS could be analysed in 837 segments (93%). In the normal subjects peak systolic CS was greatest in the endocardial layer, lower in the mid-myocardial layer, and lowest in the epicardial layer (38.1+/-9.0%, 28.9+/-9.3%, and 24.0+/-9.4%, respectively, P<0.001). In the patients with impaired LV function 151 segments were hypokinetic and 92 segments akinetic by visual analysis. In all myocardial layers peak systolic CS and strain rate decreased with decreasing segmental function.
Conclusion: Decreasing myocardial deformation from endocardial to epicardial layers can be demonstrated with the use of an advanced analysis system allowing definition of deformation parameters for three myocardial layers. Myocardial deformation is reduced in all layers of segments with impaired wall motion.