Stoddard M F
Department of Medicine, University of Louisville, KY 40203, USA.
Prog Cardiovasc Dis. 1996 Jul-Aug;39(1):69-80. doi: 10.1016/s0033-0620(96)80042-9.
Atrial fibrillation (AF), potentially serious cardiac arrhythmia, occurs in 2% to 4% of persons greater than 60 years of age. The risk of systemic thromboembolism from chronic AF has long been recognized. Little is known about the thromboembolic risk of new onset AF. However, the results of prior studies support a significant risk of thromboembolism because of recent onset or paroxysmal AF. The mechanism of thrombus formation, embolization, and resolution in AF is ill-defined, particularly that of new onset. The traditional concept holds that atrial thrombus forms only after greater than 2 days of AF and embolizes by dislodgement from increases in shear forces. This prevailing concept further proposes that newly formed atrial thrombus, in the setting of AF, organizes over a span of 14 days. The results of recent transesophageal echocardiographic studies have given insight into the temporal sequence of atrial thrombus formation, embolization, and resolution in AF and have expanded the traditional concept of thromboembolism in AF. Namely, left atrial thrombus may form before the onset of AF in the face of sinus rhythm. Conversion to sinus rhythm may increase the thrombogenic millieu of the left atrium. Importantly, atrial thrombus may form in the acute phase of AF. Lastly, thrombus may require more than 14 days to become immobile or to resolve. On the basis of these emerging insights by transesophageal echocardiography, it appears appropriate to consider anticoagulation in patients presenting with new onset or acute AF.
心房颤动（AF）是一种潜在的严重心律失常，在60岁以上人群中的发生率为2%至4%。慢性房颤引发全身血栓栓塞的风险早已为人所知。对于新发房颤的血栓栓塞风险，人们了解甚少。然而，先前研究的结果支持近期发作或阵发性房颤存在显著的血栓栓塞风险。房颤中血栓形成、栓塞和溶解的机制尚不明确，尤其是新发房颤的机制。传统观念认为，心房血栓仅在房颤持续超过2天后形成，并因剪切力增加导致的血栓脱落而发生栓塞。这一普遍观念还进一步提出，在房颤情况下新形成的心房血栓会在14天内机化。近期经食管超声心动图研究的结果，深入揭示了房颤中心房血栓形成、栓塞和溶解的时间顺序，并扩展了房颤血栓栓塞的传统概念。也就是说，在窦性心律时，左心房血栓可能在房颤发作前就已形成。转为窦性心律可能会增加左心房的血栓形成环境。重要的是，心房血栓可能在房颤急性期形成。最后，血栓可能需要超过14天才能变得固定不动或溶解。基于经食管超声心动图的这些新见解，对于新发或急性房颤患者考虑进行抗凝治疗似乎是合适的。
