Normal reference values of left atrioventricular coupling index on two-Dimensional echocardiography

The close relationship between left atrial (LA) and left ventricular (LV) dynamics is defined as coupling. The left atrioventricular coupling index (LACI) assessment may reflect LV dysfunction and differentiate between normal and abnormal LV function. This study aims to establish the normal reference values of LACI based on age and sex using Two-dimensional echocardiography (2DE). The study included 975 healthy subjects (mean age 51.2 ± 18 years, 51.6% females) with good 2DE image quality for measuring end-diastolic volumes of both LA and LV. LACI was calculated as the ratio of LA to LV end-diastolic volumes and expressed as a percentage. Subjects were divided into 4 age groups (Group I: 14-39 years, Group II: 40-59 years, Group III: 60-79 years and Group IV: ≥ 80 years). LACI measurements were obtained through offline analysis of 2DE apical views in a short time (1.5 ± 0.3 min) with excellent inter and intraobserver agreement. In the overall population, the mean LACI was 16.4 ± 7.3% significantly higher in females (17.3 ± 7.9%) than males (15.4 ± 6.6%); P < 0.001. In both sexes, increasing age was associated with a significant increase in LACI (P < 0.0001); particularly between the youngest and oldest age groups. Using 2DE, measuring LACI is feasible and reliable. Normal LACI values have been established by gender and age in a large population. Age and gender should be taken into account when defining the normal reference values for LACI.