INFLUENCE OF BODY-SIZE AND AGE ON MITRAL RING MOTION

Left ventricular systolic and diastolic function can be assessed by st udying mitral ring motion. Reference values for a wide range of age an d body size are lacking however. The motion of the mitral ring was stu died with M-mode echocardiography using the apical four-and two-chambe r views. Data are reported as the average of measurements of four poin ts on the mitral ring. Data were analysed using the stepwise multiple regression technique, with age, gender, height, weight, body surface a rea and heart rate as independent variables. A total of 70 healthy sub jects were studied. In children and adolescents under age 18, there wa s strong correlation between mitral ring motion and body size, age and heart rate. The ring motion was best described as mitral ring motion (mm)=2.2+0.078 x height (cm) (SEE=1.0 mm). In adults, mitral ring moti on was correlated with age, height and heart rate but not with weight or body surface area. Ring motion could be described from the followin g equations: mitral ring motion (mm)=12.7-0.060 x age (years)+0.031 x height (cm) (SEE=1.2) or, if only age is taken into account, mitral ri ng motion = 18.4-0065 x age (SEE=1.2). In both children and adolescent s up to age 18 and in adults, atrial contribution correlated significa ntly and positively to age and inversely to heart rate but not to heig ht, weight, body surface area or gender. Atrial contribution was best described by the equation: atrial contribution = 0.15 + 0.0039 x age ( SEE=0.027). Thus, age and body size influences mitral ring motion and should be taken into account when interpreting patient data.