Fig. 1. Function of LA during normal sinus rhythm and during AF.

In normal sinus rhythm, LA function consists of 1) LA reservoir function at LV systole, 2) LA conduit function during early LV diastole, and 3) LA pump function at late LV diastole. In contrast to sinus rhythm, AF results in rapid and inconsistent heart motion, which may be associated with blurring heart contours on cardiac images. AF = atrial fibrillation, LA = left atrium, LV = left ventricle