John Radcliffe Hospital, Oxford University Hospitals Foundation Trust (M.L., M.P., K.R., M.R.G., Y.B., T.R.B.).
Barts Heart Centre, London (R.J.H.).
Circ Arrhythm Electrophysiol. 2020 Oct;13(10):e008316. doi: 10.1161/CIRCEP.120.008316. Epub 2020 Sep 8.
Low radiofrequency powers are commonly used on the posterior wall of the left atrium for atrial fibrillation ablation to prevent esophageal damage. Compared with higher powers, they require longer ablation durations to achieve a target lesion size index (LSI). Esophageal heating during ablation is the result of a time-dependent process of conductive heating produced by nearby radiofrequency delivery. This randomized study was conducted to compare risk of esophageal heating and acute procedure success of different LSI-guided ablation protocols combining higher or lower radiofrequency power and different target LSI values.
Eighty consecutive patients were prospectively enrolled and randomized to one of 4 combinations of radiofrequency power and target LSI for ablation on the left atrium posterior wall (20 W/LSI 4, 20 W/LSI 5, 40 W/LSI 4, and 40 W/LSI 5). The primary end point of the study was the occurrence and number of esophageal temperature alerts per patient during ablation. Acute indicators of procedure success were considered as secondary end points. Long-term follow-up data were also collected for all patients.
Esophageal temperature alerts occurred in a similar proportion of patients in all groups. Significantly, shorter radiofrequency durations were required to achieve the target LSI in the 40 W groups. Less than 50% of the radiofrequency lesions reached the target LSI of 5 when using 20 W despite a longer radiofrequency duration. A lower rate of first-pass pulmonary vein isolation and a higher rate of acute pulmonary vein reconnection were recorded in the group 20 W/LSI 5. A lower atrial fibrillation recurrence rate was observed in the 40 W groups compared with the 20 W groups at 29 months follow-up.
When guided by LSI, posterior wall ablation with 40 W is associated with a similar rate of esophageal temperature alerts and a lower atrial fibrillation recurrence rate at follow-up if compared with 20 W. These data will provide a basis to plan future randomized trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02619396.
为了防止食管损伤，在进行房颤消融时，通常会在左心房后壁使用低射频功率。与较高功率相比，它们需要更长的消融时间来达到目标病变尺寸指数（LSI）。消融过程中食管的加热是由附近射频输送产生的传导加热的时间依赖性过程。这项随机研究旨在比较不同 LSI 指导的消融方案（结合较高或较低的射频功率和不同的目标 LSI 值）在食管加热和急性程序成功方面的风险。
连续 80 例患者前瞻性入组，并随机分为 4 组，分别采用不同的射频功率和目标 LSI 进行左心房后壁消融（20 W/LSI 4、20 W/LSI 5、40 W/LSI 4 和 40 W/LSI 5）。该研究的主要终点是消融过程中每位患者食管温度报警的发生和数量。急性程序成功的指标被视为次要终点。所有患者还收集了长期随访数据。
所有组的患者中食管温度报警的发生率相似。重要的是，在 40 W 组中，达到目标 LSI 需要的射频时间更短。尽管射频时间较长，但使用 20 W 时，不到 50%的射频病灶达到目标 LSI 5。在 20 W/LSI 5 组中，首次通过肺静脉隔离的比例较低，急性肺静脉再连接的比例较高。与 20 W 组相比，40 W 组在 29 个月随访时的房颤复发率较低。
在 LSI 指导下，与 20 W 相比，后壁消融使用 40 W 时食管温度报警的发生率相似，随访时房颤复发率较低。这些数据将为计划未来的随机试验提供依据。注册：网址：https://www.clinicaltrials.gov。唯一标识符：NCT02619396。
