Catheter ablation of complex left atrial arrhythmias in patients after percutaneous or surgical mitral valve procedures.

BACKGROUND: Mitral valve defects are frequently associated with atrial arrhythmias. Percutaneous or surgical mitral valveprocedures may reverse adverse haemodynamic consequences of the valvular defect but have little effect on the arrhythmiaitself. With safety concerns and few outcome data, the role of catheter ablation in these patients has not been established yet.

AIM: To assess safety and efficacy of catheter ablation of complex left atrial arrhythmias in patients after percutaneous orsurgical mitral valve procedures.

METHODS: We studied 14 patients (mean age 55 ± 11 years; 9 females) with a history of percutaneous mitral commissurotomy (PMC; n = 5), surgical valvuloplasty (n = 3), or mitral valve replacement (n = 6) due to mitral stenosis (MS; n = 8) or mitral regurgitation (MR; n = 6). In surgically treated patients, concomitant pulmonary vein isolation was performed in 6 patients and tricuspid valvuloplasty in 4 patients. Atrial fibrillation (AF) was the only arrhythmia in 7 patients, including all 5 patients after PMC (paroxysmal AF in 2 patients, persistent AF in 4 patients, long-persistent AF in 1 patient). Left atrial tachycardia (AT) was the prevailing arrhythmia in 7 of 9 patients after surgical procedures (median of 2 morphologies per patient), lasting uninterrupted for 1 to 48 months before the ablation procedure. The ablation scheme was adjusted to the clinical and electrophysiological status and included pulmonary vein isolation, linear lesions and ablation of fragmented potentials. Atrial tachycardias were mapped and ablated using activation and entrainment mapping.

RESULTS: Efficacy of ablation after a single procedure was 36%. A total of 25 ablations were ultimately performed in the study group. During 23 ± 13 months of follow-up, stable sinus rhythm (SR) was present in 10 (71.4%) patients, including 4 on antiarrhythmic drugs. No differences in the efficacy of ablation were seen between patients with MS and MR, with SR obtained in5 of 8 patients and 5 of 6 patients, respectively (p = 0.57). Similarly, no differences in regard to SR maintenance were noted between patients previously treated by a percutaneous or surgical procedure (percutaneous treatment: SR in 3 of 5 patients; surgical treatment: SR in 7 of 9 patients, p = 0.58). SR was obtained in 5 of 7 patients in whom the original arrhythmia was AF and in 5 of 7 patients who had AT (p = 1.00). Patients in whom stable SR was obtained showed a significantly better functional status as assessed by the New York Heart Association classification, accompanied by a reduction of the left atrial dimension and an increase in the left ventricular ejection fraction.

CONCLUSIONS: Catheter ablation of complex left atrial arrhythmias in patients after percutaneous or surgical mitral valve proceduresis an effective and safe therapeutic option. Recurrences after the first ablation are frequent and patients may require repeat ablations. Achieving stable SR significantly reduces complaints related to the arrhythmia and improves patient clinical status.