Abstract 13893: Sickle Cell Disease Alters Myocardial Deformation Mechanics: A Study of Cardiac Strain and Strain Rate in East African Children
Introduction: In sickle cell disease (SCD) increased circulating volume related to anemia increases cardiac preload and increased right ventricular afterload related to pulmonary hypertension may be seen. While systolic function is thought to be normal with normal shortening fractions, little is known about segmental myocardial deformation in affected children.
Methods: We studied 193 children with sickle cell disease (7-19 yrs, mean of 13.7 yrs) from the Muhimbili Sickle Cohort in Dar Es-Salaam, Tanzania and compared them to 51 confirmed normal sibling controls (8-18 yrs, mean of 13.3 yrs). Longitudinal myocardial mechanics from the apical window were analyzed using speckle tracking technique (EchoPac, GE Medical System, BT08) and averaged over 3 cardiac cycles. The end-systolic strain (S), peak systolic strain rate (SR) and the time to this peak (TTP), early (E) and late (A) diastolic strain rate waves were measured. We reported global values for the left ventricle (LV) and segmental values for LV free wall, septum and right ventricular (RV) free wall.
Results: Global S and SR for the LV did not differ between SCD and controls (p>0.05). However, segmental changes were noted (see table) with lower values in the base and mid-segments of the heart of the SCD children but higher in the RV apex. SR did not show a significant difference except in mid-septum and basal lateral segments. Eight of the nine segments showed significant lengthening of TTP in SCD patients (p<0.05). In diastole, SCD patients showed significant lower SR E waves in mid-septum and basal LV segments and higher diastolic SR A waves in basal septal and RV apex (p<0.05).
Conclusion: Despite normal fractional shortening in all patients, there a disturbance of cardiac deformation related to SCD. This manifests as a delay in the time to peak SR in almost all cardiac segments, a decrease in basal S, and, interestingly, some potentially compensatory increase in RV apical S and SR. Diastole is similarly affected with a decrease in early and an increase in late diastolic SR suggesting early diastolic dysfunction with relatively heightened dependence on atrial contraction. Further study is required to evaluate if changes in cardiac deformation track with worsening SCD.
- © 2011 by American Heart Association, Inc.