Huo Y, Arya A, Gaspar T, Richter S, Schoenbauer R, Sommer P, Bollmann A, Hindricks G, Piorkowski C
Department of Electrophysiology, Leipzig Heart Center, University of Leipzig, 04289, Leipzig, Germany.
Herzschrittmacherther Elektrophysiol. 2012 Jun;23(2):121-7. doi: 10.1007/s00399-012-0174-1.
Radiofrequency ablation of focal atrial tachycardias (AT) is a validated technique with high success rates. However, electrophysiological (EP) characteristics and ablation strategy of localized reentrant AT originating from the coronary sinus ostium (CSo) have not been reported in detail so far.
From January 2009 to July 2010, 1,453 patients underwent clinically motivated EP studies. Four patients were diagnosed with localized reentrant AT originating from the CSo. P wave morphology and consistency of tachycardia cycle length were studied. Subsequently, if reentry was suggested as an underlying mechanism for AT, color-coded 3-dimensional (3D) entrainment mapping was performed to localize the reentrant circuit or differentiate a localized reentrant AT from macroreentant AT, and also confirm reentry as an underlying mechanism of AT by evaluating consistency of return cycles after entrainment at multiple sites in both atria. Finally, activation mapping was performed to localize the earliest activation site.
The P wave morphologies and isoelectric line between the P waves suggested most likely an AT originating from the CSo with a centrifugal activation pattern, which was confirmed by activation mapping. Consistency of return cycles and continuously fragmented local electrograms at successful ablation sites suggested reentry as an underlying AT mechanism. Color-coded 3D entrainment mapping in all 4 patients located the reentrant circuit in the CSo. There were also two specific features observed. One was fragmented and/or double potentials recorded in the CSo with prominent prolonged electrogram duration compared to those during sinus rhythm. The other is a significant conduction delay within the CS. The myocardium of the CSo was suggested as a part of the critical isthmus within the reentrant circuit, while the rest of atria distal to the CSo and myocardial coat of the distal CS were not involved in the tachycardia circuit, which was confirmed by entrainment mapping.
Although CSo myocardium has been implicated to be a part of atrioventricular nodal reentrant tachycardia, to the best of our knowledge, this is the first report showing the localized reentrant AT confined to the CSo. Three of our patients (75%) had concomitant atrial fibrillation (AF). Further studies should be warranted to clarify the role of AT from the CS in triggering AF.
局灶性房性心动过速（AT）的射频消融是一种已获验证且成功率较高的技术。然而，迄今为止，源于冠状窦口（CSo）的局限性折返性房性心动过速的电生理（EP）特征及消融策略尚未得到详细报道。
2009年1月至2010年7月，1453例患者接受了基于临床目的的电生理检查。4例患者被诊断为源于CSo的局限性折返性房性心动过速。对P波形态及心动过速周期长度的一致性进行了研究。随后，如果提示折返是房性心动过速的潜在机制，则进行彩色编码三维（3D）拖带标测以定位折返环，或将局限性折返性房性心动过速与大折返性房性心动过速相鉴别，并且通过评估在双心房多个部位拖带后的返回周期的一致性来确认折返是房性心动过速的潜在机制。最后，进行激动标测以定位最早激动部位。
P波形态及P波之间的等电位线提示最可能是源于CSo的房性心动过速，呈离心性激动模式，这一点通过激动标测得以证实。成功消融部位的返回周期一致性及持续碎裂的局部电图提示折返是房性心动过速的潜在机制。所有4例患者的彩色编码3D拖带标测均将折返环定位于CSo。还观察到两个特定特征。一个是在CSo记录到碎裂和/或双电位，与窦性心律时相比，电图持续时间显著延长。另一个是冠状窦内存在明显的传导延迟。CSo心肌被认为是折返环内关键峡部的一部分，而CSo远端的其余心房及远端冠状窦的心外膜未参与心动过速环，这一点通过拖带标测得以证实。
尽管CSo心肌被认为是房室结折返性心动过速的一部分，但据我们所知，这是首次报道局限于CSo的局限性折返性房性心动过速。我们的3例患者（75%）合并心房颤动（AF）。需要进一步研究以阐明源于冠状窦的房性心动过速在触发AF中的作用。
