Periprocedural anticoagulation after ablation of right-sided supraventricular tachycardias: a prospective randomized pilot study

Background Thromboembolic events such as deep vein thrombosis, pulmonary embolism and right atrial thrombus formation are uncommon yet clinically relevant complications following right-sided catheter ablation procedures. Purpose In this randomized controlled pilot study, we aimed to assess the safety and efficacy of different periprocedural anticoagulation strategies with regard to postprocedural thromboembolic and bleeding complications in patients undergoing right-sided ablations. Methods Sixty-three patients with a history of paroxysmal supraventricular tachycardia (PSVT) underwent electrophysiological testing. After confirming a right-atrial tachycardia mechanism, patients were randomized into three groups: Group 1 received no anticoagulation; Group 2 received a weight-adjusted intravenous unfractionated heparin (UFH) bolus immediately after randomization; Group 3 received an intraprocedural UFH bolus followed by a two-week prophylactic-dose novel oral anticoagulant (NOAC). Echocardiography and lower-limb Duplex ultrasound of the puncture site were performed on the first postprocedural day and again between days 10 and 14. The primary efficacy endpoint was a composite of any thromboembolic event, including in-situ thrombosis after sheath removal, echocardiographic detection of right atrial thrombus, ultrasound-verified lower-extremity thrombosis, or clinically apparent deep vein thrombosis or pulmonary embolism. The primary safety endpoint included any bleeding or puncture-related complication. Results We analyzed data from 61 patients (35 female) undergoing right-sided ablation between January 2024 and February 2025 (88.5% AVNRT, 5% focal atrial tachycardia, 6.5% right-sided accessory pathway). One patient was lost to follow-up. The primary efficacy endpoint occurred in 8, 1 and 0 patients in Groups 1, 2 and 3, respectively (p=0.0011). All eight in-situ thrombotic events appeared in the non-anticoagulated group, with none in the other groups (p=0.0001). One patient in Group 2 developed deep vein thrombosis and pulmonary embolism on day 7. The primary safety endpoint occurred in 1, 1 and 0 patients in Groups 1, 2 and 3 (p>0.9999). One bleeding event was identified on day 14 in Group 2, and one puncture-related arteriovenous fistula was diagnosed on day 7 in Group 1. Conclusions Thromboembolic complications were significantly more frequent in patients without anticoagulation. Bleeding risk did not differ substantially among the study groups. These findings suggest that periprocedural anticoagulation is safe and may reduce post-ablation thromboembolic events in right-sided ablations. A larger multicenter randomized trial is warranted to confirm the optimal anticoagulation approach in this patient population.