Gaps in the Ablation Line as a Potential Cause of Recovery From Electrical Isolation and Their Visualization Using MRI
Gaps in the Ablation Line as a Potential Cause of Recovery From Electrical Isolation and Their Visualization Using MRI
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DOI：
10.1161/circep.110.960567
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发表时间：
2011-06-01
影响因子：
8.4
通讯作者：
Halperin, Henry R.
中科院分区：
文献类型：
--
作者：
Ranjan, Ravi;Kato, Ritsushi;Halperin, Henry R.
背景-消融术已成为治疗心房颤动和室性心动过速的重要手段，但复发率仍然很高。已经确定的是，消融线可以是不连续的，并且通过消融线中的间隙的传导可以受到组织加热的影响。在这项研究中，我们期待在整个消融线与间隙的组织导电性和传播的电波前沿的效果，使用模拟和animal model.Methods和Results-For的模拟，我们实现了一个2维bidomain模型的心脏合胞体，模拟消融线与不同长度，导电性和方向的间隙。对于动物模型，在7只杂种犬中创建具有间隙的透壁消融线。差距长度逐渐减小，直至出现传导阻滞。然后使用MRI对具有间隙的消融线进行成像，并与组织学相关联。在差距中具有正常电导率并且消融线平行于纤维方向取向的情况下，模拟预测表现出传导阻滞的最大间隙长度为1.4 mm。随着电导率降低，具有传导阻滞的最大间隙长度显著增加，即，电导率为正常的67%，传导阻滞的最大间隙长度增加到4 mm。在犬研究中，通过大体病理学测量的显示传导阻滞的最大间隙长度与通过MRI测量的最大间隙长度具有良好的相关性（R（2）为0.81）。传导阻滞可能发生在不连续的消融线上。此外，随着传导率随时间的恢复，具有表现出急性传导阻滞的大间隙的消融线可以随时间恢复在差距中的传播，从而允许心律失常的复发。使用MRI能够清晰地看到间隙，这将允许靶向这些部位进行消融。(Circ心律失常电生理学2011;4：279-286）。
Background-Ablation has become an important tool in treating atrial fibrillation and ventricular tachycardia, yet the recurrence rates remain high. It is well established that ablation lines can be discontinuous and that conduction through the gaps in ablation lines can be affected by tissue heating. In this study, we looked at the effect of tissue conductivity and propagation of electric wave fronts across ablation lines with gaps, using both simulations and an animal model.Methods and Results-For the simulations, we implemented a 2-dimensional bidomain model of the cardiac syncytium, simulating ablation lines with gaps of varying lengths, conductivity, and orientation. For the animal model, transmural ablation lines with a gap were created in 7 mongrel dogs. The gap length was progressively decreased until there was conduction block. The ablation line with a gap was then imaged using MRI and was correlated with histology. With normal conductivity in the gap and the ablation line oriented parallel to the fiber direction, the simulation predicted that the maximum gap length that exhibited conduction block was 1.4 mm. As the conductivity was decreased, the maximum gap length with conduction block increased substantially, that is, with a conductivity of 67% of normal, the maximum gap length with conduction block increased to 4 mm. In the canine studies, the maximum gap length that displayed conduction block acutely as measured by gross pathology correlated well (R(2) of 0.81) with that measured by MRI.Conclusions-Conduction block can occur across discontinuous ablation lines. Moreover, with recovery of conductivity over time, ablation lines with large gaps exhibiting acute conduction block may recover propagation in the gap over time, allowing recurrences of arrhythmias. The ability to see gaps acutely using MRI will allow for targeting these sites for ablation. (Circ Arrhythm Electrophysiol. 2011;4:279-286.)