Himel Herman D, Dumas John H, Kiser Andy C, Knisley Stephen B
Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7575, USA.
Physiol Meas. 2007 Jun;28(6):611-23. doi: 10.1088/0967-3334/28/6/001. Epub 2007 May 3.
Failure of cardiac antiarrhythmic ablation to block action potential conduction produces poor outcomes which lead to repeat procedures. To overcome this, an intraoperative index of the quality of an ablation lesion is needed. We hypothesized that a rise in the translesion stimulus-excitation delay (TED) can indicate a continuous, transmural, linear lesion, and that the TED is related to the path length in the viable tissue around the lesion. Rabbit hearts were isolated, perfused with a warm physiological solution and stained with transmembrane potential-sensitive fluorescent dye. Radiofrequency (RF) ablation was performed on ventricular epicardium with a vacuum-assisted coagulation device to produce either a complete or incomplete lesion. Complete lesions were both transmural and continuous. Incomplete lesions were noncontinuous or nontransmural. The TED was determined with bipolar stimulation at one side of the lesion and either a bipolar electrogram at the other side or optical mapping on both sides. Hearts were then stained with tetrazolium chloride and examined histologically to estimate minimum path lengths of viable tissue from the stimulation site to the recording site. Complete lesions increased the TED by factors of 2.6-3.1 (p < 0.05), whereas incomplete lesions did not significantly increase the TED. Larger minimum path lengths were found for cases that had an increased TED. The TED was quantitatively predictable based on a conduction velocity of 0.38-0.49 m s(-1), which is typical of rabbit hearts. The TED significantly increases when a linear lesion is complete, suggesting that an intraoperative measurement of the TED may help to improve ablation lesions and outcomes. Predictability of the TED based on the viable tissue path suggests that quantitative TEDs for clinical lesions may be anticipated provided that the conduction velocity is considered.
心脏抗心律失常消融术未能阻断动作电位传导会导致预后不良，进而需要重复手术。为克服这一问题，需要一种术中评估消融损伤质量的指标。我们假设跨损伤刺激-兴奋延迟（TED）的增加可表明形成了连续的、透壁的、线性的损伤，且TED与损伤周围存活组织中的路径长度相关。将兔心脏分离，用温热的生理溶液灌注，并用跨膜电位敏感荧光染料染色。使用真空辅助凝固装置对心室心外膜进行射频（RF）消融，以产生完全或不完全损伤。完全损伤是透壁且连续的。不完全损伤是不连续或非透壁的。通过在损伤一侧进行双极刺激，并在另一侧进行双极电图记录或两侧进行光学标测来确定TED。然后用氯化三苯基四氮唑对心脏进行染色，并进行组织学检查，以估计从刺激部位到记录部位的存活组织的最小路径长度。完全损伤使TED增加了2.6 - 3.1倍（p < 0.05），而不完全损伤并未显著增加TED。TED增加的病例中发现了更大的最小路径长度。基于0.38 - 0.49 m s(-1)的传导速度（这是兔心脏的典型速度），TED在数量上是可预测的。当线性损伤完全时，TED显著增加，这表明术中测量TED可能有助于改善消融损伤及预后。基于存活组织路径对TED的可预测性表明，只要考虑传导速度，就可以预期临床损伤的定量TED。
