Introduction: Catheter ablation may be complicated by clinical thromboembolism in about 1% of patients.
Methods and results: We studied the activation of coagulation (prothrombin fragment 1+2 [PF1+2]), platelets (beta-thromboglobulin [beta-TG])) and fibrinolysis (plasmin-antiplasmin complexes [PAP] and D-dimer) during radiofrequency (RF) ablation in 13 patients. They received heparin 100 U/kg intravenously after the initial electrophysiologic study, prior to the delivery of RF current; thereafter 1,000 U/hour throughout the procedure. PF1+2 increased fourfold (P < 0.001) during the diagnostic study, but gradually declined to upper reference value during heparin administration. There was a strong correlation between procedure duration prior to heparin bolus (range 39 to 173 min); and (a) the maximal rise of PF1+2 (r = 0.83, P < 0.001) and (b) the increase of PF1+2 from baseline to end of the procedure (r = 0.74, P = 0.004). There was no correlation between postheparin changes of PF1+2 and (a) postheparin procedure duration (range 40 to 317 min), (b) number of RF pulses (range 1 to 16), or (c) RF current duration (range 46 to 687 sec). Plasma beta-TG concentration showed similar trends. Fibrinolytic activity increased moderately from baseline until heparin administration; then remained around the upper reference values. PAP at the end of procedure and D-dimer at the time of heparin administration both correlated with preheparin procedure duration (r = 0.70, P = 0.007 and r = 0.69, P = 0.01, respectively). All parameters were normal the next morning.
Conclusion: Procedure duration prior to heparin administration, and not the delivery of RF current per se, determines activation of hemostasis and fibrinolysis during RF ablation.