Introduction Periprocedural anticoagulation is recommended for patients with typical atrial flutter (AFL) undergoing catheter ablation. Few data exist on the safety of this. We compared outcomes following a change of anticoagulation protocol at our institution from low molecular weight heparin (LMWH) to uninterrupted warfarin around the time of ablation.

Methods Data were collected on 100 consecutive unselected patients undergoing ablation of AFL who required periprocedural anticoagulation. The first 50 had their warfarin replaced with LMWH around the time of their procedure and the subsequent 50 had uninterrupted warfarin. Telephone follow-up regarding bleeding or anticoagulation problems took place 6 weeks post-procedure and all were seen at 3 months.

Results Procedural international normalised ratio (INR) was higher in the warfarin group (2.1 ± 0.5 vs 1.4 ± 0.6, p<0.001). There was no difference in success or major complications (table). There were fewer access site problems in the warfarin group (30% vs 46%, p = 0.049). Four patients in the LMWH group and one in the wafarin group sought further medical help for their groin problems, and three patients in the LMWH group required hospital admission (one haematoma, one pseudoanyeursm, one extensive bruising). Cost analysis showed mean cost per patient of anticoagulation with LMWH to be £105.20 ± 5.74 compared with £19.88 ± 3.95 in the warfarin group, assuming NHS pricing (p<0.0001). Transoesophageal echocardiography was performed in nine patients in the warfarin group and three patients in the LMWH before ablation due to subtherapeutic INR readings within 6 weeks before the procedure (p = 0.059).

Conclusions Catheter ablation of typical AFL without interruption of warfarin is safer and more cost effective than periprocedural conversion to LMWH. It should be adopted as the preferred anticoagulation strategy.