Impact of left ventricular diastolic dysfunction on left atrial volume and function: a volumetric analysis

Diastolic dysfunction may result in elevation of left ventricular (LV) and atrial pressures, resulting in left atrial (LA) remodelling. We examined the effects of LV diastolic dysfunction on LA volume and function.

We measured LA volume and function in 83 patients with normal LV systolic function. The LV diastolic function grade was defined using traditional Doppler measures of diastolic function. LA volumes were measured using the ellipsoid method. Maximum LA volume (Vol(max)) was indexed to the body surface area(.) The passive filling, conduit and active emptying volumes were estimated and corrected for indexed LA Vol(max). Indexed LA Vol(max) was strongly associated with LV diastolic function grade (Spearman P < 0.01, r(s) = 0.79). An indexed LA Vol(max) > 19.7 mL/m(2) predicted diastolic dysfunction with 97% sensitivity and 96% specificity. Compared with normal controls, corrected passive filling and conduit volumes were lower, and corrected active emptying volume was higher in patients with Grade I diastolic dysfunction (0.38 vs. 0.51, P = 0.02; 1.65 vs. 3.29, P < 0.001; 0.59 vs. 0.44, P = 0.001), resulting in a similar corrected total emptying volume (0.97 vs. 0.96, P= ns). Patients with higher grades of diastolic dysfunction, however, had lower corrected passive filling, conduit, active, and total emptying volumes.

LA remodelling occurs in patients with LV diastolic dysfunction and LA volume expressed the severity of diastolic dysfunction. Initially, the LA compensates for changes in LV diastolic properties by augmenting active atrial contraction. As the severity of diastolic dysfunction increases, this compensatory mechanism fails as atrial mechanical dysfunction sets in, resulting in lower total atrial emptying volume.