Catheter Ablation Using Half-Normal Saline and Dextrose Irrigation in an Ovine Ventricular Model

Objectives: This study hypothesized that catheter ablation in healthy ovine ventricular myocardium using low ionic 0.45% saline (half-normal saline [HNS]) and nonionic 5% dextrose in water (D5W) would result in larger lesions compared with use of 0.9% saline (normal saline [NS]).

Background: Limited data exist regarding the safety and efficacy of catheter ablation using low and nonionic irrigants.

Methods: Open irrigated ablation was performed on 14 beating ovine hearts (NS, n = 5; HNS, n = 4; D5W, n = 5). Ablation was delivered by using identical parameters (ie, 30 W in power control mode, 60-second duration, contact force of 10-20 g in the endocardial ventricles and 5-10 g in the epicardium). Catheter orientation and tissue contact were optimized by using intracardiac echocardiography. Lesion width, depth, and volume and number of steam pops were compared.

Results: Overall, 196 lesions were analyzed (mean duration: 56.7 ± 8.3 seconds; mean contact force: 15.3 ± 6.1 g; and mean impedance drop: 31 ± 19.1 Ω). Compared with NS, HNS and D5W resulted in larger lesion volumes (NS 349.2 ± 245.1 mm³ vs HNS 645.7 ± 386.4 mm³ vs D5W 633.2 ± 387.1 mm³; HNS vs NS; P < 0.001; D5W vs NS; P < 0.001; D5W vs HNS; P = 0.87). However, D5W was associated with higher steam pop occurrence (NS 5% vs HNS 11% vs D5W 35%; HNS vs NS; P = 0.22; D5W vs NS; P < 0.001; D5W vs HNS; P = 0.002).

Conclusions: Catheter ablation with HNS and D5W resulted in larger ablation lesions compared with NS but similar lesion dimensions between HNS and D5W. The increase in lesion size with HNS and D5W was associated with a higher incidence of steam pops, especially with D5W, compared with NS.