Squara Fabien, Maeda Shingo, Aldhoon Bashar, Marginiere Julie, Santangeli Pasquale, Chik William W, Michele John, Zado Erica, Marchlinski Francis E
Department of Cardiology, Pasteur University Hospital, Nice, France.
J Cardiovasc Electrophysiol. 2014 Oct;25(10):1125-32. doi: 10.1111/jce.12479. Epub 2014 Jul 23.
Irrigated radiofrequency (RF) catheters allow tissue-electrode interface cooling, decreasing thrombus risk while enabling higher RF power delivery. The impact of irrigation with ice-cold saline (ICS) instead of conventional ambient-temperature saline (ATS) on lesion formation is unknown.
We performed 120 RF ablations in vitro on porcine left ventricles, using ICS (<5 °C) or ATS (21 °C) irrigation. For ICS irrigation, the irrigation circuit was cooled externally to maintain delivery of cooled saline at the catheter's tip. We applied 20 g of contact force, and delivered 20 W (irrigation 8 or 17 mL/min) or 30 W (irrigation 17 or 30 mL/min) RF power. Temperatures at tissue-electrode interface and 3-mm depth were assessed by fluoroptic probes. Lesion dimensions were assessed. ICS irrigation cooled the tissue-electrode interface better than ATS (53.9 ± 9.6 °C vs. 63 ± 11.4 °C, P < 0.001). Temperatures at 3-mm depth were similar at 30 W using ICS and ATS (104.2 ± 9.3 °C vs. 105.8 ± 7.3 °C, P = 0.5), but were cooler at 20 W using ICS (71.3 ± 11.6 °C vs. 100.2 ± 11.9 °C, P < 0.001). This translated into smaller lesions at 20 W with ICS versus ATS. At 30 W with 17 mL/min flow rate, lesions had the same depth with ICS and ATS (4.9 ± 0.8 mm vs. 5.4 ± 0.7 mm, P = 0.13) but were narrower with ICS (7.7 ± 0.8 mm vs. 9.3 ± 1.2 mm, P = 0.001). At 30 mL/min, lesions had the same dimensions. Steam pop rate was similar using ICS or ATS irrigation.
ICS irrigation more effectively cools tissue-electrode interface than ATS. This may improve RF safety by potentially decreasing thrombus formation, thus facilitating safe ablation at a low saline volume load. However at lower RF power, ICS reduced lesion size compared to ATS.
灌流射频（RF）导管可实现组织 - 电极界面冷却，降低血栓形成风险，同时能够传递更高的射频功率。与传统常温盐水（ATS）相比，用冰冷盐水（ICS）进行灌流对损伤形成的影响尚不清楚。
我们在猪左心室上进行了120次体外射频消融，采用ICS（<5°C）或ATS（21°C）灌流。对于ICS灌流，灌流回路进行外部冷却，以维持在导管尖端输送冷却的盐水。我们施加20 g的接触力，并传递20 W（灌流8或17 mL/min）或30 W（灌流17或30 mL/min）的射频功率。通过荧光光纤探头评估组织 - 电极界面和3 mm深度处的温度。评估损伤尺寸。ICS灌流比ATS能更好地冷却组织 - 电极界面（53.9±9.6°C对63±11.4°C，P<0.001）。在30 W时，使用ICS和ATS时3 mm深度处的温度相似（104.2±9.3°C对105.8±7.3°C，P = 0.5），但在20 W时，使用ICS时温度更低（71.3±11.6°C对100.2±11.9°C，P<0.001）。这导致在20 W时，与ATS相比，使用ICS时损伤更小。在30 W且流速为17 mL/min时，使用ICS和ATS时损伤深度相同（4.9±0.8 mm对5.4±0.7 mm，P = 0.13），但使用ICS时损伤更窄（7.7±0.8 mm对9.3±1.2 mm，P = 0.001）。在30 mL/min时，损伤尺寸相同。使用ICS或ATS灌流时蒸汽泡发生率相似。
与ATS相比，ICS灌流能更有效地冷却组织 - 电极界面。这可能通过潜在地减少血栓形成来提高射频安全性，从而在低盐量负荷下促进安全消融。然而，在较低射频功率下，与ATS相比，ICS会减小损伤尺寸。
