Sparks P B, Jayaprakash S, Vohra J K, Mond H G, Yapanis A G, Grigg L E, Kalman J M
Department of Cardiology, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia.
J Am Coll Cardiol. 1998 Aug;32(2):468-75. doi: 10.1016/s0735-1097(98)00253-8.
This study examined the effect of radiofrequency ablation (RFA) on left atrial (LA) and left atrial appendage (LAA) function in humans with chronic atrial flutter (AFL).
Atrial stunning and the development of spontaneous echocardiographic contrast (SEC) is a consequence of electrical cardioversion of AFL to sinus rhythm. This phenomenon has been termed "stunning" and is associated with thrombus formation and embolic stroke. Radiofrequency ablation is now considered to be definitive treatment for chronic AFL, but whether this procedure is complicated by LA stunning is unknown.
Fifteen patients with chronic AFL undergoing curative RFA underwent transesophageal echocardiography to evaluate LA and LAA function and SEC before and immediately, 30 minutes and 3 weeks after RFA. To control for possible direct effects of RFA on atrial function, seven patients undergoing RFA for paroxysmal AFL were also studied. In this group, RF energy was delivered in sinus rhythm and echocardiographic parameters were assessed before and immediately and 30 minutes following RFA.
Chronic AFL: Mean arrhythmia duration was 17.2 +/- 13.3 months. Twelve patients (80%) developed SEC following RF energy application and reversion to sinus rhythm. LAA velocities decreased significantly from 54.0 +/- 14.2 cm/s in AFL to 18.0 +/- 7.1 cm/s in sinus rhythm after arrhythmia termination (p < 0.01). These changes persisted for 30 minutes. Following 3 weeks of sustained sinus rhythm, significant improvements in LAA velocities (68.9 +/- 23.6 vs. 18.0 +/- 7.1 cm/s, p < 0.01) and mitral A-wave velocities (49.8 +/- 10.3 vs. 13.4 +/- 11.2 cm/s, p < 0.01) were evident and SEC had resolved in all patients. Paroxysmal AFL: Radiofrequency energy delivered in sinus rhythm had no significant effect on any of the above indexes of LA or LAA function and no patient developed SEC following RFA.
Radiofrequency ablation of chronic AFL is associated with significant LA stunning and the development of SEC. Left atrial stunning is not secondary to the RF energy application itself. Sustained sinus rhythm for 3 weeks leads to resolution of these acute phenomena. Left atrial stunning occurs in the absence of direct current shock or antiarrhythmic drugs, suggesting that its mechanism may be a function of the preceding arrhythmia rather than the mode of reversion.
本研究探讨了射频消融（RFA）对慢性心房扑动（AFL）患者左心房（LA）及左心耳（LAA）功能的影响。
心房顿抑及自发超声心动图显影（SEC）的出现是AFL转复为窦性心律后的结果。这种现象被称为“顿抑”，并与血栓形成及栓塞性卒中相关。射频消融目前被认为是慢性AFL的确定性治疗方法，但该操作是否会并发LA顿抑尚不清楚。
15例接受根治性RFA的慢性AFL患者在RFA前、RFA后即刻、30分钟及3周接受经食管超声心动图检查，以评估LA及LAA功能和SEC。为控制RFA对心房功能可能的直接影响，还对7例因阵发性AFL接受RFA的患者进行了研究。在该组中，射频能量在窦性心律下释放，在RFA前、RFA后即刻及30分钟评估超声心动图参数。
慢性AFL：平均心律失常持续时间为17.2±13.3个月。12例患者（80%）在施加射频能量并转复为窦性心律后出现SEC。心律失常终止后，LAA速度从AFL时的54.0±14.2 cm/s显著降至窦性心律时的18.0±7.1 cm/s（p<0.01）。这些变化持续30分钟。在持续窦性心律3周后，LAA速度（68.9±23.6 vs. 18.0±7.1 cm/s，p<0.01）和二尖瓣A波速度（49.8±10.3 vs. 13.4±11.2 cm/s，p<0.01）有显著改善，且所有患者的SEC均消失。阵发性AFL：在窦性心律下释放的射频能量对上述任何LA或LAA功能指标均无显著影响，且RFA后无患者出现SEC。
慢性AFL的射频消融与显著的LA顿抑及SEC的出现相关。左心房顿抑并非继发于射频能量的应用本身。持续3周的窦性心律可使这些急性现象消失。左心房顿抑在无直流电休克或抗心律失常药物的情况下发生，提示其机制可能是先前心律失常的作用而非转复方式。
