Regional left ventricular rotation and back-rotation in patients with reverse septal curvature hypertrophic cardiomyopathy

This study sought to investigate regional left ventricular (LV) rotation in patients with hypertrophic cardiomyopathy (HCM).

The study comprised 44 patients with HCM with a typical reverse septal curvature (age 40 ± 14 years, 33 men) and 44 healthy volunteers (age 39 ± 14 years, 32 men) in whom LV rotation could be assessed at the basal and apical LV level with speckle-tracking echocardiography, using the QLAB Advanced Quantification Software version 6.0 (Philips, Best, The Netherlands). In HCM patients, lower values of initial counter-clockwise rotation at the basal LV level (1.5 ± 1.2 vs. 0.6 ± 0.9°, P < 0.001) were seen, in particular in the septal segment (1.7 ± 1.6 vs. 0.4 ± 0.7°, P < 0.001). After this period, the direction of rotation changed to clockwise with a peak basal rotation of −4.8 ± 2.0° in controls vs. −6.1 ± 2.5° in HCM patients (P < 0.05). Peak basal rotation in HCM patients was in particular higher in the anterior (−6.6 ± 3.0 vs. −4.4 ± 2.4°, P < 0.01) and septal (−5.4 ± 2.6 vs. −3.9 ± 1.9°, P < 0.05) segments. The normalized (corrected for peak basal rotation) global back-rotation rate was lower in HCM patients (4.1 ± 3.1 vs. 6.3 ± 4.9 s^–1, P < 0.05), in particular driven by a lower rate in the septal segment (3.8 ± 2.6 vs. 6.4 ± 4.8 s⁻¹, P < 0.01). At the apical level, changes in rotation and back-rotation were more homogeneous.

Changes in rotation and back-rotation at the LV basal level in HCM patients are mainly caused by regional changes in the basal septal and anterior segments, the segments mostly involved in the hypertrophic process.