Cardiovascular Division, Kings College London BHF Centre, London, United Kingdom.
Heart Rhythm. 2011 Feb;8(2):304-12. doi: 10.1016/j.hrthm.2010.10.039. Epub 2010 Oct 31.
Assessment of lesion size and transmurality is currently via indirect measures. Real-time image assessment may allow ablation parameters to be titrated to achieve transmurality and reduce recurrences due to incomplete lesions.
The purpose of this study was to visualize lesion formation in real time using a novel combined ultrasound and externally irrigated ablation catheter.
In an in vivo open-chest sheep model, 144 lesions were delivered in 11 sheep to both the atria and the ventricles, while lesion development was monitored in real time. Energy was delivered for a minimum of 15 seconds and a maximum of 60 seconds, with a range of powers, to achieve different lesion depths. Twenty-two lesions were also delivered endocardially. The ultrasound appearance was assessed and compared with the pathological appearance by four independent blinded observers.
For the ventricular lesions (n = 126), the mean power delivered was 6.1 ± 2.0 W, with a mean impedance of 394.7 ± 152.4 Ω and with an impedance drop of 136.4 ± 100.1 Ω. Lesion depths varied from 0 to 10 mm, with a median depth of 3.5 mm. At tissue depths up to 5 mm, changes in ultrasound contrast correlated well (r = 0.79, R(2) = 0.62) with tissue necrosis. The depth of ultrasound contrast correlated poorly with the depth of the zone of hemorrhage (r = 0.33, R(2) = 0.11), and impedance change correlated poorly with lesion depth (r = 0.29, R(2) = 0.08).
Real-time lesion assessment using high-frequency ultrasound integrated into an ablation catheter is feasible and allows differentiation between true necrosis and hemorrhage. This may lead to safer and more efficient power delivery, allowing more effective lesion formation.
目前，对病变大小和透壁性的评估是通过间接测量进行的。实时图像评估可能允许调整消融参数以实现透壁性，并减少因不完全病变导致的复发。
本研究的目的是使用新型联合超声和外部灌流消融导管实时可视化病变形成。
在活体开胸绵羊模型中，11 只绵羊的心房和心室共进行了 144 次消融，同时实时监测病变发展。能量输送时间最短 15 秒，最长 60 秒，功率范围从低到高，以实现不同的病变深度。还在心内膜进行了 22 次消融。由四名独立的盲法观察者评估超声表现，并与病理表现进行比较。
对于心室病变（n = 126），平均输送功率为 6.1 ± 2.0 W，平均阻抗为 394.7 ± 152.4 Ω，阻抗下降 136.4 ± 100.1 Ω。病变深度从 0 到 10 mm 不等，中位数为 3.5 mm。在组织深度达 5 mm 时，超声对比度的变化与组织坏死高度相关（r = 0.79，R² = 0.62）。超声对比度深度与出血区深度相关性较差（r = 0.33，R² = 0.11），而阻抗变化与病变深度相关性较差（r = 0.29，R² = 0.08）。
使用集成到消融导管中的高频超声实时进行病变评估是可行的，并允许区分真正的坏死和出血。这可能导致更安全和更有效的功率输送，从而更有效地形成病变。
