Use of Global Functional Index in the Assessment of Diastolic Dysfunction

Abstract

Purpose Tissue doppler techniques used in assessment of diastolic function is less load dependent than standard doppler techniques. However the existing tissue doppler indices do not adequately define stages of diastolic dysfunction in the setting of atrial fibrillation. The aim of this study is to develop novel tissue doppler parameters for staging diastolic dysfunction in patients in atrial fibrillation. The global functional index (GFI), defined as [E/Ea]/Sa, (E = peak velocity of the mitral inflow wave, Ea = peak early diastolic tissue doppler image velocity, and Sa = peak systolic tissue doppler image velocity) has been used in this study for the first time to stage diastolic dysfunction. Methods and Materials Retrospective analysis was conducted on two study populations. Group A consisted of 215 subjects with diastolic dysfunction in normal sinus rhythm and 60 control subjects also in normal sinus rhythm. The same analysis was extended to group B a set of study subjects in atrial fibrillation with and without diastolic dysfunction. Group B had 78 subjects. Of these twenty five subjects had normal diastolic function while 53 were in different stages of diastolic dysfunction. In both groups A and B statistical analyses were performed to compute the correlation of GFI with the four stages (1-4) of diastolic dysfunction. Results GFI appears to increase linearly with worsening diastolic dysfunction in groups A and B. Correlation coefficient r = 0.979 (p less than 0.001) for GFI versus stages 1 to 4 of diastolic dysfunction in group A. R=0.95 (p less than 0.001) for group B. GFI also linearly increases with increasing left atrial pressures and decreasing Sa values as diastolic dysfunction worsens. (p less than 0.01). Conclusions Therefore GFI appears to be a composite tissue doppler index which may be useful in objectively evaluating diastolic dysfunction in both sinus and non–sinus rhythms.