Assessment of left atrial mechanics and energetics in dogs using wave intensity analysis

摘要

During atrial systole, the LA acts as a booster pump contributing additional volume to fill the LV at the end of diastole (transmitral A wave). However, at high volume loads and in certain disease states, such as diastolic dysfunction, LA contraction causes blood to move retrograde into the pulmonary veins (Ar wave). The purpose of this study is to provide an energetic analysis of LA contraction, which will give insight into the mechanisms responsible for changes in the A and Ar waves. Wave intensity analysis was performed at the mitral valve and pulmonary venous orifice. The results demonstrate a growing reflected wave associated with increased LV stiffness that decelerates the forward movement of blood. Further, this reflected wave is transmitted through the LA and accelerates the retrograde movement of blood in the pulmonary veins. These results further enhance our understanding of the mechanisms involved during late diastolic filling.