Time interval determination from left atrial appendage ejection flow in patients with mitral stenosis

The feasibility of determining the time interval from left atrial appendage (LAA) flow was examined using transesophageal Doppler echocardiography. Time intervals were compared between LAA flow and mitral flow patterns during late diastole in 8 patients with mitral stenosis and in 12 controls. The start of ejection flow from the LAA was later than the initiation of mitral flow, but the termination was same in both flows, indicating the contribution of LAA ejection to the latter half of the left atrial booster pump function. The pre-ejection time and the time interval from P-wave to end-ejection correlated significantly with left atrial dimensions (r = 0.55, and r = 0.70, respectively). The pre-ejection time, duration of the ejection flow from the LAA, and duration of mitral flow in the atrial contraction phase were significantly longer in patients with mitral stenosis (126 +/- 14 msec, 131 +/- 36 msec, and 167 +/- 28 msec, respectively) than in the controls (109 +/- 13 msec, 108 +/- 15 msec, and 141 +/- 17 msec, respectively). These results indicate that electrical conduction time from the right atrium to LAA can be estimated from the LAA ejection flow, and the time is related to the left atrial size. In patients with mitral stenosis, LAA contraction may contribute to left ventricular filling in the latter half of the atrial contraction phase.