A novel multi-layer approach of measuring myocardial strain and torsion by 2D speckle tracking imaging in normal subjects and patients with heart diseases

BackgroundThis study adopted a new multi-layer approach of measuring myocardial deformation by two-dimensional (2D) speckle tracking imaging to examine whether a transmural gradient exists in normal subjects and cardiac diseases.MethodsEighty patients were included with 20 in each group: (1) normal control; (2) acute coronary syndrome (ACS) with ejection fraction (EF) > 45%; (3) right ventricular apical (RVA) pacing with EF > 45%; (4) systolic heart failure (SHF) with EF < 45%. Circumferential strain (ε-circum), torsion (Tor) and systolic dyssynchrony defined as the maximal difference in the time to peak circumferential strain were measured in the subendocardial and subepicardial myocardium layers (QLab 6.0, Philips).ResultsIn all the 4 groups, a subendocardial to subepicardial gradient was present in both ε-circum (− 20.7 ± 7.6 vs. − 14.9 ± 5.6%, p < 0.001) and Tor (12.0 ± 6.0 vs. 9.3 ± 4.7°, p < 0.05), with higher values in the subendocardial layer. However, it was significantly narrowed for ε-circum (2.7 ± 1.2%) and Tor (0.8 ± 0.9°) in SHF patients (all p ≤ 0.001 vs. other groups). On the contrary, systolic dyssynchrony measured in the 2 layers showed no difference (264 ± 107 vs. 273 ± 110 ms, p = NS) and a homogenous distribution in ε-circum was observed from basal to apical planes (− 17.0 ± 6.8 vs. − 18.1 ± 7.4 vs. − 18.1 ± 7.8%, all p = NS).ConclusionsA transmural gradient exists in circumferential strain and torsion, with higher values in the subendocardial layer. It might be reduced when systolic function is impaired. Therefore, the multi-layer approach of 2D speckle tracking imaging provides further information on assessment of myocardial diseases.