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)