Radiofrequency Catheter Ablation:

Abstract

The success and safety of standard catheter radiofrequency ablation may be limited for ablation of atrial fibrillation and ventricular tachycardia. The aim of this study was to characterize and compare different cooled and noncooled catheter systems in terms of their specific lesion geometry, incidence of impedance rise, and crater and coagulum formation to facilitate appropriate catheter selection for special indications. The study investigated myocardial lesion generation of three cooled catheter systems (7 Fr, 4-mm tip): two saline irrigation catheters with a showerhead-type electrode tip (sprinkler) and a porous metal tip and an internally cooled catheter. Noncooled catheters (7 Fr) had a large tip electrode (8 mm) and a standard tip electrode (4 mm). RF energy was delivered on isolated porcine myocardium superfused with heparinized pig blood (37 degrees C) at power settings of 10-40 W. Both irrigated systems were characterized by a large lesion depth (8.1 +/- 1.6 mm) and a large lesion diameter (13.8 +/- 1.6 mm). In comparison, internally cooled lesions showed a similar lesion depth (8.0 +/- 1.0 mm), but a significantly smaller lesion diameter (12.3 +/- 1.2 mm,P = 0.04). Large tip lesions had a similar lesion diameter (14.5 +/- 1.6 mm), but a significantly smaller lesion depth (6.3 +/- 1.0 mm,P = 0.002) compared to irrigated lesions. However, lesion volume was not significantly different between the three cooled and the large tip catheter. To induce maximum lesion size, power requirements were three times higher for the irrigation systems and two times higher for the internally cooled and the large tip catheter compared to the standard catheter. Impedance rise was rarest with irrigated and large tip ablation. In case of impedance rise crater formation was a frequent observation (61-93%). Irrigated catheters prevented coagulum formation most effectively. Irrigated rather than internally cooled ablation appears to be most adequate for the induction of deep and long lesions at a low rate of impedance rise and thrombus formation. Large tip ablation may be feasible for the creation of long linear lesions, however, with an increased risk of thrombus formation.

Powstanie zakrzepu w prawym przedsionku po zabiegu ablacji cieśni żylno-trójdzielnej mimo nieprzerwanej antykoagulacji i niskiego ryzyka zakrzepowo-zatorowego

“…The most likely explanation could be a tissue overheating with an energy application and coagulum formation resulting in thrombus formation. This has been described with non-cooled large tip ablation catheters [2]. Moreover, the fact that the mass was formed shortly after RF application and was not attached to the long sheath or any catheter and was situated close to the site of the ablation lesion supports that diagnosis.…”

Ablação do flutter atrial típico: estudo prospectivo e randomizado do cateter irrigado fechado versus cateter com eletrodo distal de 8 mm

“…Our study demonstrates a significant increase in troponin I and CK-MB levels in both groups, but with no statistical differences between cooled-tip and 8-mm tip catheters. Dorwarth et al 29 have demonstrated that that the irrigation system causes lesions with similar diameters, but significantly deeper than lesions caused by the 8-mm tip catheter; howerver, lesion volume was not significantly different between the 2 types of catheters.…”

Comparison of Renal Artery, Soft Tissue, and Nerve Damage After Irrigated Versus Nonirrigated Radiofrequency Ablation

“…With the introduction of saline irrigation during radiofrequency ablation of atrial fibrillation, a tremendous reduction in tissue damage was reported while preserving the spatial and circumferential ablation zone. 20 Therefore, the main purpose of using saline irrigation for renal radiofrequency denervation is to protect renal arterial damage by controlling surface temperature at the ablation site. 13,14 Our results suggest that such success can be achieved without significant reduction of nerve damage.…”