Normal values fetal modified myocardial performance index in the russian population and association with gestational age

Objective. The modified myocardial performance index (mod-MPI) is a non-invasive Doppler index for evaluation of left ventricular systolic and diastolic function. The MPI index is considered to be a reliable early marker of fetal cardiac dysfunction and may indicate the initial stages of adaptation of the heart to various perinatal complications. In order to use the myocardial performance index to assess fetal cardiac function, it’s necessary to determine normal values of MPI in the Russian population and compare the values depending on the period of pregnancy. Materials and methods . A Doppler study was conducted on two hundred fetuses with normal heart anatomy. Determing Mod-MPI values were based on techniques described by Hernandez et al. The measured time intervals: isovolumetric contruction time (ICT), ejection time (ET), isovolumetric relaxation time (IRT). Three consecutive measurements of all parameters were determined and the MPI index was calculated from the average value of each interval according to the formula: PI=(ICT+IRT)/ET. Results . The average value of ICT was 31±3 mc in the 2 nd trimester of pregnancy and 30±3 in the third. The average value of ET was 169±9 mc in the 2 nd trimester of pregnancy and 170±10 in the third. The average value of IRT was 38±4 mc in the 2 nd trimester of pregnancy and 37±4 in the third. The average value of mod-MPI was 0,39±0,03. There were no association between the mod-MPI values and gestational age. Conclusions. The mod-MPI is a marker of fetal myocardial disfunction. The use of myocardial performance index is currently limited due to the lack of normative reference ranges and standardized techniques for measuring the estimated time periods. The modified technique was designed to help measure time intervals for calculation of the MPI.