Background: The prognosis for children with idiopathic dilated cardiomyopathy (IDC) is variable. Patients who fail to exhibit improvement in left ventricular (LV) function have a high 1-year mortality rate, whereas improvement in LV fractional shortening (LVFS) to >15% is associated with better survival. However, complete recovery of LV performance to normal has not been examined.
Methods and results: The clinical features and echocardiograms of 63 children with IDC were reviewed. Sixteen patients (group 1) were identified who demonstrated progressive improvement in LVFS, ultimately recovering to within the normal range. They were compared with 47 patients (group 2) in whom LVFS remained depressed. Group 1 LVFS at first examination was 13.6% +/- 5.1%, z = -10.8 +/- 4.0, and improved to within the normal range (33.7% +/- 3.4%, z = -0.9 +/- 1. 4, P <.001). Group 2 initial LVFS was 13.6 +/- 2.3, z = -8.9 +/- 3.2 and did not change significantly (15.7% +/- 7.3%, z = -7.3 +/- 1.6). The LV was dilated at initial examination in all patients (z = 6.9 +/- 3.0). Recovery in group 1 was associated with a decrease in LV dimension to within the normal range (z = 1.3 +/- 1.6, P <.001), whereas the LV dimension in group 2 patients remained increased (z = 6.2 +/- 3.4). The mean follow-up time at which LV function was noted to be normal was 4.5 +/- 3.6 years (range 0.3 to 14 years). The total duration of follow-up was 6.5 +/- 5.2 years (range 1 to 16 years).
Conclusions: Complete recovery of LV function is possible in children with IDC. Recovery may occur within the first year after initial examination in some patients, but longer periods are needed in the majority of patients in whom LV function ultimately returned to normal.