Key result
Perpendicular catheter orientation yields ~1.1 mm deeper lesions than parallel alignment in papillary muscle ablation.
Why the study?
Papillary muscle ablation for refractory ventricular arrhythmias is challenging, and no prior study had investigated the association between catheter orientation and lesion size.
Does perpendicular catheter orientation compared to parallel catheter orientation increase ablation lesion depth and volume during radiofrequency ablation of papillary muscle tissue?
Does perpendicular catheter orientation compared to parallel catheter orientation increase ablation lesion depth and volume during radiofrequency ablation of papillary muscle tissue?
Answers are grounded in this paper and cite their sources.
In an ex vivo bovine model, orienting an open-irrigated ablation catheter perpendicular rather than parallel to papillary muscle tissue significantly increases lesion depth and more than doubles lesion volume without causing steam pops.
INTRODUCTION: Ablation of papillary muscles (PMs) for refractory ventricular arrhythmias can often be challenging. The catheter approach and orientation during ablation may affect optimal radiofrequency (RF) delivery. Yet, no previous study investigated the association between catheter orientation and PM lesion size. We evaluated ablation lesion characteristics with various catheter orientations relative to the PM tissue during open irrigated ablation, using a standardized, experimental setting. METHODS: Viable bovine PM was positioned on a load cell in a circulating saline bath. RF ablation was performed over PM tissue at 50 W, with the open irrigated catheter positioned either perpendicular or parallel to the PM surface. Applied force was 10 g. Ablation lesions were sectioned and underwent quantitative morphometric analysis. RESULTS: , p < .001) and (3.33 ± 0.18 mm vs. 2.24 ± 0.10 mm, p < .001), respectively. There were no significant differences in initial impedance, peak voltage, peak current, or overall decrease in impedance among groups. Parallel catheter orientation resulted in higher peak temperature (41.33 ± 0.28°C vs. 40.28 ± 0.24°C, p = .003), yet, there were no steam pops in either group. CONCLUSION: For PM ablation, catheter orientation perpendicular to the PM tissue achieves more effective and larger ablation lesions, with greater lesion depth. This may have implications for the chosen ventricular access approach, the type of catheter used, consideration for remote navigation, and steerable sheaths.
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Nussinovitch et al. (2022) studied Papillary muscle-related ventricular arrhythmias (ex vivo bovine papillary muscle ablation model) (n=80). Perpendicular catheter orientation during open-irrigated radiofrequency ablation vs. Parallel catheter orientation during open-irrigated radiofrequency ablation (50 W for 60 seconds with 10 g contact force) was evaluated on Maximum ablation lesion depth (mm) (p=<0.001). Perpendicular catheter orientation during papillary muscle ablation produced deeper (3.33 vs 2.24 mm, p<0.001) and larger (75.26 vs 34.04 mm³, p<0.001) lesions than parallel orientation.
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