Half versus normal saline irrigation during catheter ablation of outflow tract ventricular arrhythmias (HALF): a multi-center, parallel, open-label, randomized controlled study.

BACKGROUND: Animal studies demonstrated that deeper lesions could be achieved during radio-frequency catheter ablation (RFCA) by using half saline (HS) compared to normal saline (NS) as irrigation. OBJECTIVES: This study sought to compare the efficiency and safety of HS and NS for irrigation during RFCA of idiopathic outflow tract ventricular arrhythmia (OT-VA). METHODS: In this multicenter, randomized controlled study, 167 patients undergoing RFCA of OT-VA were randomized 1:1 to receive HS- or NS-irrigated ablation. Acute success was defined as the absence of induced targeted premature ventricular contraction (PVC) at the end of the procedure. The 6-month success was defined as a ≥ 80% reduction of pre-procedural PVC burden. RESULTS: There were no differences of baseline characteristics between the HS and NS group. Patients in HS group had shorter total ablation time (259.5 ± 155.5 S vs. 355.6 ± 230.7 S, P = 0.04) than that in NS group. The acute and 6-month success rates were similar between the HS and NS group (92.8 vs. 91.7%, P = 0.79; 90.9 vs. 92.1%, P = 0.79, respectively). No significant difference was observed in the incidence of steam pops between the HS and NS group (2.4 vs. 1.2%, P = 0.62). CONCLUSIONS: The ablation using HS irrigation achieved similar success rate and safety compared to that using NS irrigation but was associated with a shorter total ablation time. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2200059205).