Left ventricular strain, rotation, and torsion as markers of acute myocardial ischemia

Abstract

This study investigates how tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) describe regional myocardial deformation during controlled reductions of left anterior descending (LAD) coronary artery perfusion pressure. In eight anesthetized pigs, a shunt with constrictor was installed from the brachiocephalic artery to the LAD. Data were obtained with open shunt, followed by four degrees of stenosis (S1-S4) of increasing severity: S1, ∼15%; S2, ∼35%; S3, ∼50%; and S4, ∼60% reductions of LAD perfusion pressure. At each situation, microspheres for perfusion measurements were injected and left ventricular (LV) short- and long-axis cineloops were recorded. In the anterior wall, radial, circumferential, and longitudinal one-layer STE strain, one-layer radial TDI strain, and three-layer radial TDI and STE strain were measured. LV peak mean rotation was measured at six equidistant levels from apex to base (in 7 pigs). LV torsion was calculated from end-systolic mean rotation. With open shunt, three-layer TDI analysis showed a transmural strain gradient with no perfusion gradient. Perfusion, one-layer TDI strain, and strain in the mid- and subendocardium from three-layer TDI were reduced at S2 (P < 0.05). STE strain was not affected until S3 (P < 0.05). Peak mean rotation, increasing toward the apex, decreased at the three apical levels at S4 (P < 0.05). LV torsion did not decrease (P = 0.26). In conclusion, TDI strain detected dysfunction already with minor changes in global hemodynamics, whereas STE strain was first reduced with moderate changes. LV peak mean rotation was not reduced until severe reduction of LAD perfusion pressure, but remained increasingly counterclockwise toward the apex. LV torsion remained unaffected by ischemia.

Is strain by Speckle Tracking Echocardiography dependent on user controlled spatial and temporal smoothing? An experimental porcine study

“…Moreover, independent of the degree of smoothing, all strain values corresponded well to findings from previous studies in both normal and ischemic myocardium [10,18,20,27-30]. Different smoothing settings are therefore not likely to be a major contributor to the variances in strain reported in the literature [4].…”

“…After premedication with a mixture of ketamine, diazepam and atropine, anesthesia was induced and maintained by loading doses and continuous infusions of fentanyl, sodium pentobarbital, midazolam and pancuronium as previously described in detail [10,11]. The animals then underwent tracheotomy and intubation.…”

Fusion of Three-Dimensional Echocardiographic Regional Myocardial Strain with Cardiac Computed Tomography for Noninvasive Evaluation of the Hemodynamic Impact of Coronary Stenosis in Patients with Chest Pain

“…There is growing evidence in the literature that regional myocardial strain may aid in the early detection of subtle changes in myocardial function caused by ischemia, when wall motion abnormality cannot be visually detected. 18,20,48–50 This ability stems from the fact that longitudinal strain mostly reflects contractile function of the subendocardial fibers, which are predominantly affected by ischemia. 51 …”

Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR

“…5 The purpose of this study was to obtain new details of global and regional radial wall motion of the left ventricle using the cardiac MR high temporal resolution myocardial velocity-encoding technique. 6,7 Considering recent interest in myocardial multilayer measurements, which provide more layer-specific information about the functional state of the myocardium at different levels, [8][9][10][11][12][13] separate calculations of all myocardial velocities and their corresponding peak times for the inner (endocardial), middle (transmural) and outer (epicardial) layers of the LV wall were performed.…”