Tissue Doppler velocities are impaired after heart transplantation and further diminished in acute rejection.

Left ventricular relaxation index (LVRI) was calculated as the sum of E′ of the left ventricular lateral, septal and posterior walls divided by left ventricular posterior wall (LVPW) thinning (LVRI = E′ lateral + E′ septal + E′ posterior/[systolic LVPW − diastolic LVPW/systolic LVPW]). On the basis of a prior study, LVRI > 0.8 was considered normal after transplantation. Serial LVRI measurements (n = 941) were analyzed in a total of 35 patients who underwent transplantation. The sensitivity and specificity of LVRI < 0.8 for detecting rejection were calculated. LVRI was compared at baseline, at diagnosis of rejection, and at recovery after rejection treatment for each patient. The potential role of ischemic graft time, pretransplantation waiting period, and pretransplantation diagnosis on LVRI recovery was also assessed.

LVRI was low early after transplantation (mean, 0.69) normalizing (mean, 0.91) at a median of 39.6 days (range, 5–115 days) after transplantation. Fifteen episodes of rejection were seen in 11 patients. LVRI was lower at diagnosis of rejection compared with baseline (P = .0013). LVRI < 0.8 had 93.3% sensitivity (95% CI, 68%–99.8%) and 89.5% specificity (95% CI, 67%–99%) for detecting all rejection. LVRI recovered at a mean of 28.3 days after onset of treatment. No correlation was found to ischemic graft time, to pretransplantation waiting period, or to pretransplantation diagnosis.

After the early posttransplantation period, serial measurements of LVRI appear to be a useful echocardiographic marker of heart transplantation rejection in children and of the effectiveness of rejection treatment. As such, this method may be of value in the ongoing clinical management of these difficult patients.