Abstract 12602: Impact of Left Ventricular Diastolic Dysfunction Grade on Left Atrial Reservoir, Conduit, and Booster Pump Function: Three-Dimensional Echocardiographic Investigation

Abstract

Background: Since three-dimensional echocardiography (3DE) does not require any geometric assumption for measuring left atrial (LA) volume, LA functional parameters obtained using 3DE could be more precise than those from two-dimensional images. However, LA volume and function determined using 3DE has never been fully investigated. We sought to elucidate the impact of left ventricular diastolic dysfunction (DD) on LA volume and function from 3DE.

Methods: LA 3DE time-volume curve was semi-automatically obtained in 405 subjects (245 men, age 66±15 years) using commercially available software (4D Auto LVQ, EchoPAC, GE). The maximal and minimal LA volume indices (LAVImax and LAVImin, respectively), and LA volume index before atrial contraction (LAVIpre-a) were determined from LA time-volume curve. LA reservoir function was expressed as expansion index [(LAVImax - LAVImin) / LAVImin], conduit function as passive emptying fraction [(LAVImax - LAVIpre-a) / LAVImax], and booster pump function as active emptying fraction [(LAVIpre-a - LAVImin) / LAVIpre-a]. In accordance with Mayo criteria, DD was classified into 4 grades using Doppler echocardiography.

Results: A hundred and eight subjects (27%) were graded as normal diastolic function, 146 (36%) as mild DD, 118 (29%) as moderate DD, and 33 (8%) as severe DD. The LAVImax increased significantly with advanced grades of DD (normal: 31.6±11.4, mild DD: 35.8±11.4, moderate DD: 45.5±17.9, severe DD: 59.5±20.1 mL/m2, P<0.001). All LA functional parameters were progressively deteriorated according to the grades of DD (expansion index: 117.5%±40.2%, 86.5%±35.6%, 62.9%±28.4%, 36.6%±25.5%; passive emptying fraction: 33.2%±10.9%, 23.4%±11.2%, 21.5%±9.3%, 18.4%±10.9%; active emptying fraction: 28.4%±9.7%, 27.3%±10.4%, 19.6%±9.3%, 9.1%±8.5%, all P<0.00l).

Conclusions: With advanced grades of DD, LA volume increased and all LA mechanistic parameters including reservoir, conduit, and booster pump function from 3DE were more severely impaired. DD could be a crucial determinant of LA functional deterioration as well as LA dilatation.