Avitall Boaz, Lizama Ken S, Kalinski Arthur, Coulombe Nicolas, Laske Timothy G
Division of Cardiology, University of Illinois at Chicago, Chicago, Illinois.
Medtronic, Montreal, Quebec, Canada.
J Cardiovasc Electrophysiol. 2019 Oct;30(10):2080-2087. doi: 10.1111/jce.14097. Epub 2019 Aug 19.
A direct indicator of effective pulmonary vein isolation (PVI) based on early ice formation is presently lacking.
The initial impedance rise within 30 to 60 seconds (sec) of single cryoablation relating to ice on the distal surface of the cryoballoon could; predict effective PVI with early termination, the need for prolonging the cryoablation, or failure to achieve effective ablation.
Impedance measurements were taken between two ring electrodes, at the anterior balloon surface and at the shaft behind the balloon. Ice covering the anterior ring leads to impedance rise. Single cryoablation (eight animals, 37 veins) was applied for 90 to 180 sec. Cryoapplication was terminated if the impedance reached ≥500 Ω. Impedance levels at ≤60 sec of cryoablation were divided into three groups based on the characteristics of the impedance rise. PVI was confirmed acutely and at 45 ± 9 days recovery by electrophysiology mapping and histopathology.
At 60 sec of freezing, an impedance rise of 34.1 ± 15.2 Ω (13-50 Ω) and slope of the impedance rise (measured during 15-30 sec of cryoapplication) less than 1 Ω/sec resulted in failed PVI. An impedance rise of 104.4 ± 31.5 Ω (76-159 Ω) and slope of 2 Ω/sec resulted in 100% PVIs. An impedance rise of 130.9 ± 137.8 Ω (40-590 Ω) and slope of 10 Ω/sec resulted in 100% PVIs with early termination at 90 sec.
The efficacy of single cryoablation can be defined within 30 to 60 sec based on ice impedance. Three unique impedance profiles described in this investigation are associated with the uniformity and thickness of the ice buildup on the anterior surface of the balloon. One cryoablation with an adequate impedance rise is needed for successful outcomes.
目前缺乏基于早期冰形成的有效肺静脉隔离（PVI）的直接指标。
单次冷冻消融30至60秒内与冷冻球囊远端表面的冰相关的初始阻抗升高，能够预测早期终止的有效PVI、延长冷冻消融的必要性或未能实现有效消融。
在两个环形电极之间、球囊前表面和球囊后方的轴处进行阻抗测量。覆盖前环的冰会导致阻抗升高。对8只动物的37条静脉进行单次冷冻消融90至180秒。如果阻抗达到≥500Ω，则终止冷冻应用。根据阻抗升高的特征，将冷冻消融≤60秒时的阻抗水平分为三组。通过电生理标测和组织病理学在急性时和恢复45±9天时确认PVI。
在冷冻60秒时，阻抗升高34.1±15.2Ω（13 - 50Ω）且阻抗升高斜率（在冷冻应用15 - 30秒期间测量）小于1Ω/秒会导致PVI失败。阻抗升高104.4±31.5Ω（76 - 159Ω）且斜率为2Ω/秒会导致100%的PVI成功。阻抗升高130.9±137.8Ω（40 - 590Ω）且斜率为10Ω/秒会导致100%的PVI成功并在90秒时早期终止。
基于冰阻抗可在30至60秒内确定单次冷冻消融的疗效。本研究中描述的三种独特阻抗曲线与球囊前表面冰堆积的均匀性和厚度相关。成功的结果需要一次具有足够阻抗升高的冷冻消融。
