Assessment of Left Atrial Work During Acute Coronary Occlusion

Left atrial (LA) work can be measured through speckle tracking echocardiography by calculating LA pressure-strain loop area, which includes two distinct phases of active contraction/relaxation (A-work) and passive dilation/emptying (V-work). Echocardiographic and hemodynamic data were acquired at baseline and during occlusions of left anterior descending (LAD: n = 7) and left circumflex (LCx: n = 9) coronary arteries in dogs. Left ventricular (LV) circumferential strain was decreased and mean LA pressure was increased in both occlusions. Doppler-derived stroke volume was maintained during LAD occlusion, but it decreased during LCx occlusion. A-work increased during LAD occlusion, but it did not change during LCx occlusion. V-work decreased during LCx occlusion more than during LAD occlusion. The compensatory mechanism of LA function was limited during LCx occlusion, but this occurred during LAD occlusion. This study provided insight into a role of LA function in variable hemodynamic consequences in acute myocardial infarction.