When should heparin preferably be administered during radiofrequency catheter ablation?

RF catheter ablation is complicated by thromboembolism in about 1% of patie nts. Limited knowledge exists concerning when and how to use anticoagulatio n or antithrombotic treatment. We studied the activation of coagulation (pr othrombin fragment 1 + 2 [PF1 + 2] and D-dimer), platelets (beta -thrombogl obulin [beta -TG]) and fibrinolysis (plasmin-antiplasmin complexes [PAP]) d uring RF ablation of accessory pathways in 30 patients. They were randomize d to receive heparin (100 IU/kg, intravenously) (1) immediately after intro duction of the femoral venous sheaths (group I) or (2) after the initial el ectrophysiological study, prior to the delivery of RF current (groups V and III). Group II additionally received saline irrigation of all femoral shea ths. After the initial bolus, 2,000 IU of heparin was supplied hourly in al l groups. Within groups II and III, median plasma values of PF1 + 2 and bet a -TG more than tripled (P less than or equal to 0.007) during the diagnost ic study and gradually declined during heparin administration despite RF cu rrent delivery. Median D-dimer tripled (P = 0.005) and PAP doubled (NS) bef ore heparin administration; then both remained around the upper reference v alues. In the early heparin group, however, PF1 + 2, D-dimer, and PAP did n ot rise at all, and beta -TG showed only a slight increase towards the end of the procedure. The differences between group I versus groups II and III were statistically significant prior to the first RF current delivery (PF1 + 2, D-dimer, and beta -TG) and by the end of the procedure (PF1 + 2, D-dim er, and PAP). In conclusion, "late" heparin administration allows hemostati c activation during the initial catheterization and diagnostic study. By ad ministering intravenous heparin immediately after introduction of the venou s sheaths, hemostatic activation is significantly decreased. Saline irrigat ion of the venous sheaths added nothing to late heparin administration.