Circumferential ablation at the base of the left ventricular papillary muscles: A highly effective approach for ventricular arrhythmias originating from the papillary muscles.

BACKGROUND: Radiofrequency catheter ablation (RFCA) of ventricular arrhythmias (VAs) originating from the left ventricular (LV) papillary muscles (PMs) is challenging.

METHODS: We enrolled 16 consecutive patients who received RFCA for VAs from LV PMs. Three-dimensional electroanatomical mapping was used to construct activation and/or pace maps. RFCA was performed first at the earliest activation site or at the best matched site in the pace maps. When an acceleration or reduction in the incidence of VAs was observed during the first few seconds of the application, the ablation energy was delivered continuously for 60-120s. Additional ablation was then circumferentially delivered at the base of the PMs.

RESULTS: RFCA was successfully performed in all 16 patients with no cases of recurrence of VAs after a mean follow-up of 20±12months. VAs originated from the anterior (n=8) and posterior (n=8) PMs. Purkinje potentials were identified at the target sites in seven patients. All VAs were temporarily suppressed by one to two long-duration shots of RFCA at the initial targeted site, but recurrence was subsequently noted. In six patients, the QRS morphologies of the VAs changed after the initial RFCA. A subsequent circumferential approach with multiple ablations applied to the base of the PMs completely eliminated all VAs. In all but one patient, successful RFCA was achieved using an open-irrigated ablation catheter.

CONCLUSIONS: Circumferential RFCA at the base of the PMs overcame anatomical limitations, leading to a high success rate of RFCA for VAs from LV PMs.