Pollick C, Taylor D
Department of Medicine, Vancouver General Hospital, British Columbia, Canada.
Circulation. 1991 Jul;84(1):223-31. doi: 10.1161/01.cir.84.1.223.
The predilection of the left atrial appendage (LAA) for thrombus formation has long been known.
We prospectively studied the two-dimensional echocardiographic and Doppler patterns of LAA function in 82 patients by transesophageal echocardiography. In the 63 patients in sinus rhythm, LAA area was measured during LAA diastole at the onset of the electrocardiographic (ECG) P wave (LAAmax) and after LAA systole at the ECG R wave (LAAmin) and LAA ejection fraction was calculated as (LAAmax-LAAmin)/LAAmax; peak Doppler velocity was recorded from the LAA outlet. The 58 patients in sinus rhythm without LAA thrombus were grouped according to left atrial size on transthoracic echocardiography; 39 patients had a left atrial size of less than 40 mm (group 1) and 19 had a left atrial size of 40 mm or greater (group 2). Five patients in sinus rhythm had LAA thrombus. In the 19 patients with atrial fibrillation or flutter LAAmax was measured independent of the ECG; three of these patients had LAA spontaneous contrast, four had thrombus, and one had both. Patients in sinus rhythm without LAA thrombus demonstrated a characteristic pattern of a contractile LAA apex and a noncontractile base with color flow and pulsed Doppler evidence of LAA emptying that coincided with the P wave. Patients in sinus rhythm with LAA thrombus had a mean +/- SD LAAmax (8.0 +/- 1.5 cm2) larger than that in group 1 (5.0 +/- 1.9 cm2) (p less than 0.01) but not group 2 (6.7 +/- 3.1 cm2), LAAmin (6.5 +/- 1.0 cm2) larger than that in both group 1 (2.3 +/- 1.5 cm2) and group 2 (4.2 +/- 2.7 cm2) (p less than 0.01), and LAA ejection fraction (17 +/- 11%) and LAA velocity (0.24 +/- 0.10 m/sec) less than those in both group 1 (55 +/- 21% and 0.48 +/- 0.24 m/sec, respectively) and group 2 (45 +/- 27% and 0.46 +/- 0.24 m/sec, respectively) (p less than 0.01). Patients with atrial fibrillation or flutter with LAA spontaneous contrast and/or thrombus had LAAmax (10.4 +/- 6.6 cm2) greater than that in patients with atrial fibrillation or flutter without LAA contrast and/or thrombus (6.8 +/- 3.0 cm2) (p less than 0.05). The LAA appeared as a static pouch in seven of eight of the former compared with in two of 11 of the latter. When attempted, Doppler demonstrated a recognizable fibrillatory LAA outflow velocity pattern in none of three in the former versus four of seven in the latter group.
We conclude that the LAA has a characteristic pattern of emptying in sinus rhythm. LAA thrombus formation in sinus rhythm and atrial fibrillation is associated with both poor LAA contraction and LAA dilation.
左心耳（LAA）易于形成血栓这一情况早已为人所知。
我们通过经食管超声心动图对82例患者的LAA功能的二维超声心动图和多普勒模式进行了前瞻性研究。在63例窦性心律患者中，于心电图（ECG）P波起始时LAA舒张期测量LAA面积（LAAmax），在ECG R波后LAA收缩期结束时测量LAA面积（LAAmin），并计算LAA射血分数为（LAAmax - LAAmin）/LAAmax；记录LAA出口处的峰值多普勒速度。根据经胸超声心动图测得的左心房大小，将58例无LAA血栓的窦性心律患者分组；39例患者左心房大小小于40 mm（第1组），19例患者左心房大小为40 mm或更大（第2组）。5例窦性心律患者有LAA血栓。在19例心房颤动或心房扑动患者中，独立于ECG测量LAAmax；其中3例患者有LAA自发显影，4例有血栓，1例两者皆有。无LAA血栓的窦性心律患者表现出LAA尖部收缩而底部不收缩的特征性模式，彩色血流和脉冲多普勒显示LAA排空与P波一致。有LAA血栓的窦性心律患者的平均±标准差LAAmax（8. ± 1.5 cm²）大于第1组（5.0 ± 1.9 cm²）（p < 0.01）但不大于第2组（6.7 ± 3.1 cm²），LAAmin（6.5 ± 1.0 cm²）大于第1组（2.3 ± 1.5 cm²）和第2组（4.2 ± 2.7 cm²）两者（p < 0.01），且LAA射血分数（17 ± 11%）和LAA速度（0.24 ± 0.10 m/秒）小于第1组（分别为55 ± 21%和0.48 ± 0.24 m/秒）和第2组（分别为45 ± 27%和0.46 ± 0.24 m/秒）两者（p < 0.01）。有LAA自发显影和/或血栓的心房颤动或心房扑动患者的LAAmax（10.4 ± 6.6 cm²）大于无LAA显影和/或血栓的心房颤动或心房扑动患者（6.8 ± 3.0 cm²）（p < 0.05）。前者8例中有7例LAA表现为静态囊袋，而后者11例中有2例如此。尝试进行时，多普勒显示前者3例中无一例有可识别的颤动LAA流出速度模式，而后者7例中有4例有。
我们得出结论，LAA在窦性心律中有特征性的排空模式。窦性心律和心房颤动中LAA血栓形成与LAA收缩不良和LAA扩张均有关。
