Michowitz Yoav, Buch Eric, Bourke Tara, Tung Roderick, Bradfield Jason, Mathuria Nilesh, Boyle Noel G, Shivkumar Kalyanam
UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Pacing Clin Electrophysiol. 2012 Nov;35(11):1294-301. doi: 10.1111/j.1540-8159.2012.03499.x. Epub 2012 Aug 16.
The usefulness of unipolar electrograms (EGMs) has been reported in assessing lesion transmurality and conduction block along ablation lines. It is unknown whether unipolar and bipolar EGM characteristics predict exit block during pulmonary vein isolation (PVI) procedures.
Twenty patients (63 ± 7 years; 14 males [70%]) undergoing PVI with a circular mapping catheter (CMC) placed outside each PV ostium were retrospectively studied. After entrance block was achieved, pacing at each bipole around the CMC was performed to assess for absence of atrial capture (exit block). Bipolar EGMs recorded before pacing were examined for voltage, duration, fractionation, and monophasic morphology. Unipolar EGMs were examined for positive and negative amplitude, PQ segment elevation, fractionation, and monophasic morphology. The association of these parameters with atrial capture (absence of exit block) at each site was analyzed. After achievement of entrance block, only 23 of 64 PV antra (36%) exhibited exit block. Unipolar EGMs at sites with persistent capture were more likely to be fractionated and had larger negative deflections. Bipolar EGMs at sites with persistent capture showed higher amplitude, longer duration, were more likely to be fractionated, and were less likely to be monophasic. In a multivariate logistic regression model, bipolar and unipolar fractionation, bipolar duration, and lack of bipolar monophasic morphology were independently associated with persistent atrial capture.
Specific unipolar and bipolar EGM characteristics are associated with left atrium capture after PV antral isolation. These parameters might be useful in predicting the need for further ablation to achieve exit block.
单极电图（EGM）在评估消融线处病变透壁性和传导阻滞方面的作用已有报道。目前尚不清楚单极和双极EGM特征是否能预测肺静脉隔离（PVI）手术期间的出口阻滞。
对20例接受PVI治疗的患者（63±7岁；14例男性[70%]）进行回顾性研究，在每个肺静脉口外放置环形标测导管（CMC）。在实现入口阻滞后，在CMC周围的每个双极处进行起搏，以评估是否存在心房夺获（出口阻滞）。检查起搏前记录的双极EGM的电压、持续时间、碎裂程度和单相形态。检查单极EGM的正负振幅、PQ段抬高、碎裂程度和单相形态。分析这些参数与每个部位心房夺获（无出口阻滞）的相关性。在实现入口阻滞后，64个肺静脉前庭中只有23个（36%）表现出出口阻滞。持续夺获部位的单极EGM更可能出现碎裂，且负向偏转更大。持续夺获部位的双极EGM显示出更高的振幅、更长的持续时间、更可能出现碎裂，且更不可能是单相的。在多变量逻辑回归模型中，双极和单极碎裂、双极持续时间以及缺乏双极单相形态与持续心房夺获独立相关。
特定的单极和双极EGM特征与肺静脉前庭隔离后左心房夺获相关。这些参数可能有助于预测是否需要进一步消融以实现出口阻滞。
