Clinical efficacy of open‐irrigated electrode cooled with half‐normal saline for initially failed radiofrequency ablation of idiopathic outflow tract ventricular arrhythmias

Background Acute failure of radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) occur in 10%‐20% of patients and is partly attributed to inadequate lesion depth acquired with standard ablation protocols. Half‐normal saline (HNS)‐irrigation is a promising strategy to improve the success rate of VA ablation. Objective This study investigated the efficacy of HNS‐irrigated ablation after a failed standard plain normal saline solution (PNSS)‐irrigated ablation on idiopathic outflow tract ventricular arrhythmia (OT‐VA). Method This is a prospective observational study of consecutive patients undergoing RFA of idiopathic OT‐VA comparing the efficacy of additional HNS‐irrigated ablation for failed standard PNSS‐irrigated ablation. Acute failure was defined as persistence of spontaneous VA or persistent inducibility of the clinical VA. Results Out of 160 OT‐VA cases (51 ± 15‐year‐old, 62 males), 31 underwent HNS irrigation after a failed standard PNSS‐irrigated ablation. The HNS group had a significantly longer procedure time (60.06 ± 43.83 vs 37.51 ± 33.40 minutes; P = .013) and higher radiation exposure (31.45 ± 20.24 vs 17.22 ± 15.25 minutes; P = .001) than the PNSS group but provided an additional acute success in 21 of 31 (67.7%) patients. Over a follow‐up duration of 7.8 ± 4.6 months, 24 recurrences were identified, including 8 (25.8%) in the HNS and 16 (12.4%) in the PNSS group, with lower freedom from recurrence in the HNS group (log rank P = .009). No major complication was observed. Conclusion HNS‐irrigated ablation after failed standard PNSS‐irrigated ablation is safe and additionally improves acute ablation success by 67.7% for idiopathic OT‐VA but with a higher rate of recurrence on follow‐up. Whether the application of HNS as initial irrigant could result in better outcome requires further investigation.