Normal values of doppler derived right ventricular myocardial perfomance index in neonates

ABSTRACT

Doppler-derived Myocardial Performance Index [MPI] is defined as the sum of isovolumetric contraction and relaxation durations divided by ejection time. It is an easily measured and reproducible index that shows both systolic and diastolic myocardial function. The goal of this study was to define normal values of right ventricular MPI in neonates in the first 48 to 72 hours of life. Patients and Fifty-one quite or asleep healthy and term neonates underwent complete M-mode, two-dimensional color-doppler echo-cardiography examination and RV MPI was calculated for them. Statistical analysis was performed, using SPSS software. P values less than 0.05 were considered as significant. RV MPI was 0.23 +/- 0.14 in healthy neonates. No correlation between RV MPI and either age or weight of the newborn infants was found. RV MPI in healthy neonates was 0.23 +/- 0.14 in our study. While this closely resembles to the results of some researches, but is lower than those previously reported by the other investigators in healthy children. The lower value of RV MPI in neonates can be possibly explained by the higher pulmonary arterial pressure of the lower ventricular mass in the first few days of life in neonates. Further studies for evaluation of the effect of pulmonary arterial pressure and right ventricular mass on RV MPI is recommended