Grimm R A, Stewart W J, Arheart K, Thomas J D, Klein A L
Department of Cardiology, Cleveland Clinic Foundation, Ohio 44195-5064, USA.
J Am Coll Cardiol. 1997 Mar 1;29(3):582-9. doi: 10.1016/s0735-1097(96)00551-7.
This study sought to determine whether left atrial appendage stunning occurs in patients with atrial flutter and to compare left atrial appendage function in the pericardioversion period with that in patients with atrial fibrillation.
Left atrial appendage stunning has recently been proposed as a key mechanistic phenomenon in the etiology of postcardioversion thromboembolic events in atrial fibrillation. Atrial flutter is thought to be associated with a negligible risk of thromboembolic events; therefore, anticoagulation is commonly withheld before and after cardioversion in these patients.
Sixty-three patients with atrial flutter (n = 19) or atrial fibrillation (n = 44) underwent transesophageal echocardiography immediately before and after electrical cardioversion. In addition to assessing the presence of thrombus and spontaneous echo contrast, we measured left atrial appendage emptying velocity and calculated shear rates by pulsed wave Doppler and two-dimensional echocardiography.
Patients with atrial flutter exhibited greater left atrial appendage flow velocities before cardioversion than those with atrial fibrillation (42 +/- 19 vs. 28 +/- 15 cm/s [mean +/- SD], p < 0.001). Left atrial appendage shear rates were also higher in patients with atrial flutter (103 +/- 82 vs. 59 +/- 37 s-1, p < 0.001). After cardioversion, left atrial appendage flow velocities decreased compared with precardioversion values in patients with atrial fibrillation (28 +/- 15 before to 15 +/- 14 cm/s after cardioversion, p < 0.001) and atrial flutter (42 +/- 19 to 27 +/- 18 cm/s, respectively, p < 0.001). Shear rates decreased from 59 +/- 37 before cardioversion to 30 +/- 31 s-1 after cardioversion in atrial fibrillation (p < 0.001), and from 103 +/- 82 s to 65 +/- 52 s-1, respectively (p < 0.001), in atrial flutter. This decrease in flow velocity from before to after cardioversion occurred in 36 (82%) of 44 patients with atrial fibrillation and 14 (74%) of 19 with atrial flutter. The impaired left atrial appendage function after cardioversion was less pronounced in the group with atrial flutter (27 +/- 18 cm/s for atrial flutter vs. 15 +/- 14 cm/s for atrial fibrillation, p < 0.001). New or increased spontaneous echo contrast occurred in 22 (50%) of 44 patients with atrial fibrillation versus 4 (21%) of 19 with atrial flutter (p < 0.05).
Left atrial appendage stunning also occurs in patients with atrial flutter, although to a lesser degree than in those with atrial fibrillation. These data suggest that patients with atrial flutter are at risk for thromboembolic events after cardioversion, although this risk is most likely lower than that in patients with atrial fibrillation because of better preserved left atrial appendage function.
本研究旨在确定心房扑动患者是否会发生左心耳功能不全，并比较复律期间左心耳功能与心房颤动患者的左心耳功能。
最近有人提出，左心耳功能不全是心房颤动复律后血栓栓塞事件病因中的一个关键机制现象。心房扑动被认为与血栓栓塞事件的风险可忽略不计；因此，这些患者在复律前后通常不进行抗凝治疗。
63例心房扑动患者（n = 19）或心房颤动患者（n = 44）在电复律前后立即接受经食管超声心动图检查。除了评估血栓和自发回声增强的存在情况外，我们还通过脉冲波多普勒和二维超声心动图测量了左心耳排空速度并计算了剪切率。
心房扑动患者复律前的左心耳血流速度高于心房颤动患者（42±19 vs. 28±15 cm/s[平均值±标准差]，p < 0.001）。心房扑动患者的左心耳剪切率也更高（103±82 vs. 59±37 s-1，p < 0.001）。复律后，心房颤动患者（复律前28±15 cm/s，复律后15±14 cm/s，p < 0.001）和心房扑动患者（分别为42±19 cm/s至27±18 cm/s，p < 0.001）的左心耳血流速度均较复律前降低。心房颤动患者复律后剪切率从复律前的59±37 s-1降至30±31 s-1（p < 0.001），心房扑动患者则从103±82 s-1降至65±52 s-1（p < 0.001）。44例心房颤动患者中有36例（82%）、19例心房扑动患者中有14例（74%）复律前后出现血流速度下降。复律后左心耳功能受损在心房扑动组中不太明显（心房扑动为27±18 cm/s，心房颤动为15±14 cm/s，p < 0.001）。44例心房颤动患者中有22例（50%）出现新的或增强的自发回声增强，而19例心房扑动患者中有4例（21%）出现（p < 0.05）。
心房扑动患者也会发生左心耳功能不全，尽管程度比心房颤动患者轻。这些数据表明，心房扑动患者复律后有发生血栓栓塞事件的风险，尽管由于左心耳功能保存较好，这种风险很可能低于心房颤动患者。
