Myocardial Performance Index in Children With Secundum Atrial Septal Defect

Quantitative assessment of ventricular function in patients with congenital heart disease is often challenging due to distorted ventricular geometry. A myocardial performance index (MPI) has been reported in adults and children that is a Doppler-derived non-geometric measure of ventricular function. The MPI measures the ratio of isovolumic time intervals to ventricular ejection time. The effects of altered ventricular preload or afterload on the MPI have yet to be determined. This study was designed to determine the impact of altered preload on left and right ventricular MPI nin the clinical setting of atrial septal defect (ASD). The left and right ventricular MPI were measured in 17 patients with ASD (ages 6 to 148 months, median 24 months) and 24 normal children (ages 3 to 160 months, median 17 months). In patients with ASD and control groups, the left ventricular MPI was 0.38±0.16 and 0.32±0.09 and the right ventricular MPI was 0.24±0.15 and 0.20±0.08 respectively. No significant change in the left and right ventricular MPI was seen in patients with atrial septal defect and control groups. This study documents that the MPI is a quantitative measure of ventricular function that is appears to be relatively independent of changes in preload.