THE USE OF HALF NORMAL SALINE AS AN IRRIGANT FOR THE CATHETER ABLATION OF TYPICAL RIGHT SIDED ATRIAL FLUTTER

Abstract

Ablation of typical atrial flutter (AFL) can be challenging and achievement of bidirectional block can be limited by complex anatomy and a lack of transmural lesions. Recent data suggest that deeper ablation lesions may be created by decreasing the irrigant ionic concentration using half normal saline (HNS) delivered through open irrigated RFA than by using normal saline (NS). We sought to test whether the use of HNS in an irrigated catheter resulted in a more rapid achievement of bidirectional block (BB) compared with NS. Patients were randomly allocated to catheter ablation with either NS or HNS using a 4mm irrigated catheter at a power setting of 30W. Ablation was performed aiming for the restoration of sinus rhythm in patients who were in AFL and bidirectional block as confirmed by double potentials separated by an isoelectric line measuring 110ms and evidence of conduction block using differential pacing. A total of 24 patients underwent catheter ablation for typical AFL (12 HNS, 12 NS). Sinus rhythm and bidirectional block were achieved in all patients. There were no significant differences between the two groups in terms of patient age (72 +/- 12 years HNS; 69 +/- 14 years NS) and duration of AFL (8 +/- 6 months HNS; 9 +/- 5 months NS). The mean duration to achieve BB using RF was 12.4 +/- 3.8 mins using HNS compared with 17.5 +/- 4.2 mins using NS (p=0.01). There were 2 steam pops in the HNS arm and 0 steam pops in the NS arm (ns). There were no significant complications in either arm. Irrigation with HNS results in achievement of bidirectional block using a shorter duration of RF compared with NS. This may be associated with a higher incidence of steam pops although this did not result in any adverse events to the patient.