Strain and strain rate echocardiography in children with Wilson's disease

This study aimed to evaluate strain and strain rate echocardiography in children with Wilson's disease to detect early cardiac dysfunction.

In this study, 21 patients with Wilson's disease and a control group of 20 age- and gender-matched healthy children were included. All the patients and the control group were evaluated with two-dimensional (2D) and colour-coded conventional transthoracic echocardiography by the same paediatric cardiologist using the same echocardiography machine (Vivid E9, GE Healthcare, Norway) in standard precordial positions, according to the American Society of Echocardiography recommendations. 2D strain and strain rate echocardiography were performed after the ECG probes of the echocardiography machine were adjusted for ECG monitoring. Longitudinal, transverse and radial strain, and strain rate were assessed from six basal and six mid-ventricular segments of the left ventricle, as recommended by the American Society of Echocardiography.

Left ventricular wall thickness, systolic and diastolic diameters, left ventricular diameters normalised to body surface area, end-systolic and end-diastolic volumes, cardiac output and cardiac index values were within normal limits and statistically similar in the patient and control groups (p > 0.05). Global strain and strain rate: the patient group had a statistically significant lower peak A longitudinal velocity of the left basal point and peak E longitudinal velocity of the left basal (VAbasR) point, and higher global peak A longitudinal/circumferential strain rate (GSRa) compared to the corresponding values of the control group (p < 0.05). Radial strain and strain rate: end-systolic rotation [ROT (ES)] was statistically significantly lower in the patient group (p < 0.05). Longitudinal strain and strain rate: end-systolic longitudinal strain [SLSC (ES)] and positive peak transverse strain (STSR peak P) were statistically significantly lower in the patient group (p < 0.05). Segmental analysis showed that rotational strain measurement of the anterior and lateral segments of the patient group were statistically significantly lower than the corresponding values of the control group (p < 0.05). Segmental analysis showed statistically significantly lower values of endsystolic longitudinal strain [STSR (ES)] of the basal lateral (p < 0.05) and end-systolic longitudinal strain [SLSC (ES)] of the basal septal segment (p < 0.05) in the patient group. End-systolic longitudinal strain [SLSC (ES)] and positive peak transverse strain (STSR peak P) were statistically significantly lower in the patient group (p < 0.05). Segmental analysis showed statistically significantly lower values of endsystolic longitudinal strain [SLSC (ES)] of the mid-anterior and basal anterior segments (p < 0.05), end-systolic longitudinal strain [STSR (ES)] measurements of the posterior and mid-posterior segments, end-systolic longitudinal displacement [DLDC (ES)] of the basal posterior, mid-posterior and mid-antero-septal segments in the patient group.

Cardiac arrhythmias, cardiomyopathy and sudden cardiac death are rare complications but may be seen in children with Wilson's disease due to copper accumulation in the heart tissue. Strain and strain rate echocardiography is a relatively new and useful echocardiographic technique to evaluate cardiac function and cardiac deformation abnormalities. Our study showed that despite normal systolic function, patients with Wilson's disease showed diastolic dysfunction and regional deformation abnormalities, especially rotational strain and strain rate abnormalities.