Decreased left ventricular torsion and untwisting in children with dilated cardiomyopathy

Abstract

The purpose of this study was to analyze left ventricular (LV) torsion and untwisting, and to evaluate the correlation between torsion and other components of LV contraction in children with dilated cardiomyopathy (DCM). Segmental and global rotation, rotational rate (Vrot) were measured at three levels of LV using the two dimensional (2D) speckle tracking imaging (STI) method in 10 DCM patients (range 0.6-15 yr, median 6.5 yr, 3 females) and 17 age- and sex-matched normal controls. Global torsion was decreased in DCM (peak global torsion; 10.9 +/- 4.6 degrees vs. 0.3 +/- 2.1 degrees , p<0.001). Loss of LV torsion occurred mainly by the diminution of counterclockwise apical rotation and was augmented by somewhat less reduction in clockwise basal rotation. In DCM, the normal counterclockwise apical rotation was not observed, and the apical rotation about the central axis was clockwise or slightly counterclockwise (peak apical rotation; 5.9 +/- 4.1 degrees vs. -0.9 +/- 3.1 degrees , p<0.001). Systolic counterclockwise Vrot and early diastolic clockwise Vrot at the apical level were decreased or abolished. In DCM, decreased systolic torsion and loss of early diastolic recoil contribute to LV systolic and diastolic dysfunction. The STI method may facilitate the serial evaluation of the LV torsional behavior in clinical settings and give new biomechanical concepts for better management of patients with DCM.

Fig. 1

Measurement of the torsion (degree). Torsion (t)=Apical LV rotation (t)-Basal LV rotation (t).

Fig. 2

(A) Profiles of apical segmental and global (dotted line) rotation (°) in a 6 month-old normal boy. Apical rotation was consistently counterclockwise (positive). (B) Profiles of apical segmental and global (dotted line) rotation (°) in a 6 month-old boy with DCM. Apical rotation was clockwise or small counterclockwise, and was markedly heterogenous.

Fig. 3

Comparison of peak global torsion in normal and DCM children. The peak global torsion was significantly decreased in DCM.

Fig. 4

(A) Profiles of apical segmental and global (dotted line) rotational rate (Vrot) (°/sec) in a 6 month-old normal boy. LV apex showed systolic counterclockwise (positive) Vrot and clockwise early diastolic (negative) Vrot. (B) Profiles of apical segmental and global (dotted line) rotational rate (Vrot) (°/sec) in a 6 month-old boy with DCM. Systolic counterclockwise Vrot and early diastolic clockwise Vrot were abolished. Considerable rotational heterogeneity was noticed particularly at the apical level.