Aims: Subendocardial layer of the ventricle has been shown to be sensitive to anthracycline damage. This study tested the hypothesis that anthracycline therapy for childhood malignancies has differential impact on deformation and rotation of left ventricular (LV) subendocardial and subepicardial layers and hence transmural myocardial strain and rotation gradients.
Methods and results: Thirty-two anthracycline-treated survivors of childhood malignancies aged 19.3 ± 5.4 years and 28 controls were studied. Apical four-chamber and parasternal LV short-axis acquisitions at base, papillary muscle level, and apex were analysed for layer-specific myocardial strain and apical and basal rotation and rotational velocities using two-dimensional speckle tracking echocardiography. Transmural strain and rotation gradients were calculated as differences between peak systolic strain and rotation between the inner and outer layers, respectively. Compared with controls, patients had significantly lower transmural circumferential, but not radial or longitudinal, strain gradients (P< 0.05), accounted by the reduced subendocardial circumferential strain, at all three ventricular levels (all P< 0.05). No significant difference in basal transmural rotation gradient was found between patients and controls (P= 0.32). On the other hand, apical rotation, systolic twisting velocity, and diastolic untwisting velocity were reduced preferentially at the subendocardial layer in patients (all P< 0.05), hence accounting for their significantly reduced transmural rotation gradient compared with controls (P< 0.001). The LV ejection fraction correlated inversely with apical transmural circumferential strain gradient (r= -0.39, P= 0.002) and rotation gradient (r= 0.33, P= 0.01).
Conclusion: Preferential impairment of subendocardial circumferential deformation and apical rotation with consequential reduction of transmural circumferential strain and rotation gradients occurs in anthracycline-treated survivors of childhood cancers.