Leon H. Charney Division of Cardiology, New York University Langone Medical Center, New York, NY, USA.
Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA.
Europace. 2018 Apr 1;20(4):596-603. doi: 10.1093/europace/euw405.
Atrial tachycardia (AT) related to atrial fibrillation (AF) ablation frequently poses a diagnostic challenge. Downstream overdrive pacing (DOP) can be used to rapidly detect reentry and assess proximity of a pacing site to an AT circuit or focus. We hypothesized that systematic DOP using multielectrode catheters would facilitate AT mapping.
DOP identified constant fusion when the post-pacing interval (PPI)-tachycardia cycle length (TCL) <40 ms and stimulus to adjacent upstream atrial electrogram interval >75% of TCL. Mapping was performed as follows: (i) CS DOP, (ii) DOP at left atrial (LA) roof, (iii) DOP at selected LA sites based on prior DOP attempts, and (iv) mapping and ablation at regions of fractionated electrograms in region of AT. Activation mapping was performed at operator discretion. AT diagnosis was confirmed by successful ablation or additional mapping when ablation was unsuccessful. Fifty consecutive patients with sustained AT underwent mapping of 68 ATs, of whom 42 (62%) were macroreentrant, 19 were locally reentrant (28%), and 7 (10%) were focal. AT was correctly identified with a median of three DOP attempts. All macroreentrant ATs were identified with ≤6 DOP attempts. One AT (1.6%) was terminated by DOP, and three ATs (4.8%) required activation mapping. Intracardiac concealed fusion was seen in 26 ATs (38%), each of which was successfully ablated.
Reentry could be demonstrated in a substantial majority of AF ablation-related AT. A stepwise diagnostic approach using DOP and recognition of intracardiac concealed fusion can be used to rapidly identify and ablate reentrant AT.
与心房颤动（AF）消融相关的房性心动过速（AT）常常构成诊断挑战。下游超速起搏（DOP）可用于快速检测折返并评估起搏部位与 AT 环或焦点的接近程度。我们假设使用多电极导管进行系统的 DOP 将有助于 AT 标测。
当起搏后间期（PPI）-心动过速周期长度（TCL）<40ms 且刺激到相邻上游心房电图的间隔>75%TCL 时，DOP 确定恒定融合。映射如下进行：（i）CS DOP，（ii）左心房（LA）顶部的 DOP，（iii）根据先前的 DOP 尝试在选定的 LA 部位进行 DOP，以及（iv）在 AT 区域的分形电图区域进行映射和消融。激活映射由操作员自行决定。通过成功消融或在消融不成功时进行额外映射来确认 AT 诊断。50 例持续性 AT 患者接受了 68 例 AT 的标测，其中 42 例（62%）为大折返性，19 例为局部折返性（28%），7 例（10%）为局灶性。通过中位数为 3 次 DOP 尝试正确识别 AT。所有大折返性 AT 均通过≤6 次 DOP 尝试识别。1 例 AT（1.6%）通过 DOP 终止，3 例 AT（4.8%）需要激活映射。在 26 例 AT（38%）中观察到心内隐匿融合，每例均成功消融。
在很大一部分与 AF 消融相关的 AT 中可以证明折返。使用 DOP 和识别心内隐匿融合的逐步诊断方法可以快速识别和消融折返性 AT。
