Abstract 17603: Left Ventricular Myocardial Mechanics at Rest and During Exercise in Children After Heart Transplant
Background: Early detection of graft dysfunction is important after pediatric heart transplantation (HTX). Stress echocardiography with visual myocardial assessment has been used to detect regional myocardial dysfunction. Studying LV myocardial mechanics using speckle-tracking echocardiography during exercise could provide more quantitative information. The aim of the study was to evaluate myocardial mechanical response to exercise in children after HTX using bicycle stress echocardiography.
Materials and Methods: A total of 43 pediatric HTX recipients and 24 age and gender matched CON were included. Median age at transplantation was 9 years (range: 0.1 to 15 years) and median time since HTX was 4.9 years (0.5 to 15.4 years). A stepwise Bruce protocol was used. LV global longitudinal peak strain (A4C view) and peak circumferential strain (mid SAX view) was measured in all subjects at rest and at incremental HR.
Results: Resting HR was higher in the HTx group than in the CON (90 ± 14 vs 72 ± 10 bpm, p<0.001) but peak HR was lower in the HTx group than in CON (141 ±12 bpm vs 165±15 bpm, p=0.01). FS at rest was higher in HTX than CON (37 ±5.4% vs. 35±2 %, p<0.001). LV peak global longitudinal strain values were lower at rest (18±1.9% vs. 20±2.2 %, p=0.0008) and peak exercise (19±2.6 % vs. 20.4±2.3 % p=0.03) in the HTx group compared to CON. No significant difference was found in LV global circumferential strain at rest (23.3±2.7% vs. 23.7±2.1 %, p=0.5) and peak exercise (26±3.7% vs. 26.4±2.7 %, p=0.5). When plotted vs. HR the increase in longitudinal and circumferential strain values were not significantly different.
Conclusions: Our data show that circumferential and longitudinal myocardial deformation is preserved in HTX compared to CON during exercise when corrected for HR. Earlier data from the same cohort, showed normal increase in systolic Tissue Doppler velocities and isovolumic acceleration. These data suggest a preserved contractile reserve during exercise in these patients.
- © 2013 by American Heart Association, Inc.