Needle-Tipped Catheter Ablation of Papillary Muscle Results in Deeper and Larger Ablation Lesions.

Abstract

Ventricular tachycardia associated with papillary muscle (PM) is often refractory to standard radiofrequency ablation (RFA). The needle-tipped ablation catheter (NT-AC) has been used to treat deep intramyocardial substrates, but its use for PM has not been characterized. Using an ex vivo experimental platform, both 3mm and 6mm NT-AC created larger ablation lesion volumes and depths than open-irrigated ablation catheter did (OI-AC; e.g., 57.12 ± 9.70mm3 and 2.42 ± 0.22mm, respectively; p < 0.01 for all comparisons). Longer NT-AC extension (6mm) resulted in greater ablation lesion volumes and maximum depths (e.g., 333.14 ± 29.13mm3 and 6.46 ± 0.29mm, respectively, compared to the shorter 3mm NT-AC extension, 143.33 ± 12.77mm3, and 4.46 ± 0.14mm; both p < 0.001). There were no steam pops. In conclusion, for PM ablation, the NT-AC was able to achieve ablation lesions that were larger and deeper than with conventional OI-AC. Ablation of PM may be another application for needle-tip ablation. Further studies are warranted to establish long-term safety and efficacy in human studies.