Evaluation of left atrial rhythm with pulsed Doppler echocardiography.

To evaluate the origin of ectopic atrial rhythms, the beginning of atrioventricular inflow due to left and right atrial ejection was estimated using the pulsed Doppler combined with two-dimensional echocardiography. In ten normal controls, the beginning of transtricuspid flow due to atrial ejection preceded that of transmitral by 0 to 40 msec with an average of 22 msec. In contrast, the beginning of right atrial ejection flow lagged behind that of left atrial by 40 to 80 msec in case 1 and by 20 to 50 msec in case 2 of ectopic atrial rhythm. The significant delay of atrioventricular inflow due to right atrial ejection in these two patients strongly suggests that the ectopic atrial rhythm is of left atrial origin. The pulsed Doppler echocardiography is considered to be a useful clinical tool for noninvasive evaluation of the left atrial rhythm.