Open-irrigated laser catheter ablation: influence of catheter–tissue contact force on lesion formation
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Catheter–tissue contact force (CF) is a major determinant for radiofrequency (RF) ablation lesion size and quality. We sought to test the influence of catheter CF on lesion formation by using an open-irrigated electrode-laser mapping and ablation (ELMA) catheter.
With the ELMA catheter in a stable vertical position, continuous wave 1064 nm laser impacts at 15 W (9.5 W/mm2), 30 s (285 J/mm2), irrigation flow 30 mL/min, were aimed at the endocardial surface of bovine myocardium in heparinized stagnant blood (ACT >350 s) at room temperature (18 °C). Lesions were produced with CFs of 100 g, 10 g, in contact but without pressure, with the catheter tip 2.0 mm, and 5.0 mm away (n = 10, each). Lesions were evaluated morphometrically and were compared by the unpaired t tests.
There were no significant differences between volumes of lesions achieved with catheter–tissue CF of 100 g, 10 g, and in contact without pressure: 297 ± 56.0 vs. 300 ± 39 vs. 320 ± 24, respectively (p > 0.05). However, volumes of lesions produced at a distance of 2 mm (95 ± 14 mm3) were significantly smaller (p < 0.0001), whereas at a distance of 5.0 mm, no lesions were produced. No steam-pop with crater or thrombus formation occurred.
By using an open-irrigated ELMA catheter, catheter–tissue CF is not a determinant for laser ablation lesion size and quality. Maximum sizes of lesions can be achieved with the catheter in intimate endocardial contact without pressure. However, lesions can be produced also at a catheter–tissue distance of 2.0 mm. Noticeably, there is no thrombus formation during laser application with the free floating ELMA catheter in the stagnant blood.
KeywordsCatheter ablation Catheter–tissue contact force Laser Open-irrigated laser catheter
This study was supported in part by the LasCor GmbH, Laser—Medical Devices, Taufkirchen, and Manufacturer of the open-irrigated ELMA catheter RytmoLas. Dr. M. Sagerer-Gerhardt is CTO and Dr. H. Weber is CEO of the LasCor Company, without any financial benefit from the company. Both the authors have full control of all primary data and both agree to allow the journal to review their data if requested.
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