Background: Catheter ablation of atrial fibrillation (AF) or atrial tachycardia (AT) in patients with mechanical mitral valve replacement (MVR) remains technically challenging. Due to the underlying mitral valve pathology and altered hemodynamics, the atrial anatomy undergoes extensive remodeling and changes in its electroanatomical features. Additionally, surgical access adds macroscopical alterations to the left atrial structure, complicating arrhythmia mechanisms. Nevertheless, these patients are prone to complex atrial arrhythmias, requiring adequate therapy concepts. Recent data suggest that radiofrequency (RF) and pulsed-field ablation are feasible and safe near mechanical prostheses in experienced centers, however little is known regarding ablation strategies for these complex patients.
Methods: We retrospectively analyzed 10 patients (mean age 53.8 ± 9.1 years, 8 male) with mechanical MVR who underwent RF ablation for AF or AT between 2018 and 2025. The mean left atrial diameter was dilated with 30 mm, and the transmitral gradient was 3.6 mmHg. All procedures were performed with 3D electroanatomical mapping under uninterrupted warfarin therapy (mean INR 2.8 ± 0.3; CHA₂DS₂-VASc 2.4). Structured follow-up with clinical visit and 12-lead ECG was performed at 3 and 12 months.
Results: All patients completed the ablation without complications, especially no bleeding risks occurred. Prior to the procedure, exclusion of thrombi was obtained with CT in all patients (10/10). RF-Ablation strategies made use of high density 3D mapping systems and included pulmonary vein isolation (PVI), linear lesions in left atrium (LA), complex fractionated atrial electrogram (CFAE) modification and cavotricuspid isthmus (CTI) ablation and choice of approach was up to operator’s discretion. Only 30% of cases were treated with PVI only, in one case, an isolated CTI line was pursued. The remaining patients were treated with PVI and additional lines and CFAE ablation. In 50% of cases, an additional or isolated CTI line was chosen. Follow-up data revealed that sinus rhythm was obtained in 40% after one ablation and in up to 90% after three ablations. Patients treated with PVI only required an average of 2.7 procedures to achieve durable sinus rhythm, whereas those undergoing extensive ablation in LA including PVI, lines and CFAE needed an average of 2.0 procedures. The addition of a CTI line significantly improved long-term success, with an average of 1.6 procedures required to maintain stable sinus rhythm.
Conclusion: Our findings further support that 3D-mapping-guided radiofrequency ablation in patients with mechanical mitral valve replacement is feasible and safe, even under continuous high-dose anticoagulation and in complex left atrial anatomies. Moreover, an ablation strategy incorporating a CTI line demonstrates superior rhythm control and significantly reduces the number of repeat procedures required for long-term sinus rhythm maintenance, and should therefore be considered as part of the ablation strategy in these challenging patients.
