Altered ventricular mechanics in cardiac allografts: a tissue Doppler study in 30 children without prior rejection events.
BACKGROUND
Tissue Doppler imaging (TDI), a non-invasive echocardiography technique, permits quantitative analysis of the regional distribution pattern of myocardial velocities. During normal childhood development, regional function changes markedly, including an increasing predominance of longitudinal velocities. This study analyzed the impact of heart transplantation on ventricular mechanics in growing children.


METHODS
TDI was performed in 30 pediatric heart transplant recipients (7.1 +/- 6.2 years) and 32 age-matched healthy children (6.8 +/- 5.4 years). Patients had no rejection history and were 3.1 years (median) post-transplant. Color TDI images from apical and parasternal views were stored as echocardiographic raw data. Off-line analysis was used to measure peak systolic and diastolic myocardial velocities in 6 basal cardiac segments for longitudinal (anterior, inferior, lateral, septal, right ventricle) and radial velocities (posterior). Isovolumic acceleration, a load-insensitive function marker, was determined as slope of the upstroke of the isovolumic contraction wave. Multiple regression modeling was used for statistics.


RESULTS
Systolic myocardial velocities still increased with age after transplantation, but the velocity distribution pattern was changed. In transplanted hearts, left ventricular longitudinal velocities were lower and radial velocities were higher than in the controls, but isovolumic acceleration was similar. In the right ventricle, longitudinal velocities and isovolumic acceleration were significantly decreased after transplantation. Wall motion abnormalities were present in 50% of patients.


CONCLUSIONS
Regional wall motion analysis shows significant alterations of the fundamental biomechanical pump function of the left ventricle after heart transplantation in children, with a shift from longitudinal to radial fibers and depressed right ventricular wall motion. This may have important implications for the long-term graft function required in children.
Pauliks
Linda B
LB
Pediatric Cardiology, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA. lpauliks@tufts-nemc.org
Pietra
Bill A
BA
Kirby
Scott
S
Logan
Loralee
L
DeGroff
Curt G
CG
Boucek
Mark M
MM
Valdes-Cruz
Lilliam M
LM
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler / Q000379:methods*; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D009200:Myocardial Contraction / Q000502:physiology*; D014184:Transplantation, Homologous; D016276:Ventricular Function / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology; D016278:Ventricular Function, Right / Q000502:physiology