Dynamic changes of mitral annular geometry during the cardiac cycle - a three-dimensional echo study in healthy volunteers

To quantify dynamic changes of the normal mitral valve annulus (MVA) during the cardiac cycle,weacquired 3Ddata sets ofMV(33+5 vps) in 53 healthy volunteers (46+14 yrs, 31 M). MVAcircumference and area (MVAc, MVAa), antero-posterior (AP) and lateral-medial (ALPM) diameters, and sphericity index (SphI) were obtained at 6 time points during the cardiac cycle: MV closure–MVC; mid-systole–MS; isovolumic relaxation time–IVRT; early (ED) and late (after P wave) diastole (LD), and before R wave. MVAa and AP changed significantly in all reference frames (p,0.001) (table, figure). Mean change was 35+10% for MVAa and 25+10% for AP. MVAc, ALPM, and SphI also change between LD and ED, then they remained stable from ED to next LD. Mean change was 35+10% for MVAc, and only 13+8% for ALPM. Thus, the largest MVAa occurs during IVRT; MVA starts to shorten after LD, and reaches a minimum at MVC. This "normal MVA dynamic pattern" can be used as a reference to analyze pathological MVA or effects on MVA after interventions performed on surrounding structures.