Effects of atrial arrhythmia catheter ablation on left ventricular function and severity of mitral regurgitation

Abstract Background/Introduction Atrial arrhythmias and mitral regurgitation (MR) often co-exist. Usually, patients with high-degree MR are considered not eligible for catheter ablation (CA) of atrial fibrillation (AF) due to perceived less favoured outcomes. However, at least in some patients with secondary MR, atrial arrhythmias may worsen the LV function, cause LA dilatation and worsening of the MR. We hypothesized that CA of atrial arrhythmias may improve the severity of MR and LV function in selected MR patients. Purpose This study aims to assess the effect of CA of atrial arrhythmias in patients with moderate and severe MR, on MR severity, left-ventriuclar ejection fraction (LVEF) and arrhythmia recurrence. Methods In this single-centre, retrospective study we included patients with moderate and severe MR who underwent CA for atrial arrhythmias While most patients had atrial fibrillation, we also included those who underwent CA for right or left atrial flutter or ectopic atrial tachycardia. Echocardiographic assessment of LV function and MR severity was performed before and after CA. During CA a voltage mapping of the left atrium was also performed. Only patients with at least 6-month of follow-up were included.All data were derived from the intrahospital electronic health files. Results Out of 300 consecutive patients referred for CA, we identified 26 patients (mean age 70 ± 8.9 y, 38.5% female) with MR ≥ 2. Mean CHADS-VASc-Score was 3 (range 1-6); 38.5% had persistent AF and 23.5% had typical flutter. Moderate MR was identified in 20 (77%) and severe MR in 6 (23%) patients. After 6 months, all patients were in sinus rhythm at the time of follow-up echocardiography. MR improved from moderate to mild in 11 and from severe to mild in 2 patients. During the follow-up, MR decreased from mean 2.2 ± 0.43 to 1.7 ± 0.72 (Z = -2.83; P = 0.005). LVEF also improved significantly from 47.5 ± 14% before to 54 ± 12% post-ablation; P = 0.0001. No significant changes in left atrial volume index (LAVI) were observed: 44.2 ± 17 to 44 ± 20; P = 0.98. Arrhythmia recurrence was observed in 7 (27%) patients; 5 of them with mild and 2 with severe MR. Conclusion The findings of this study suggest that CA of atrial arrhythmias improves MR severity as well as LVEF in patients with moderate to severe MR before ablation. Interestingly, arrhythmia-recurrence rate was not affected by the severity of the MR. This study is limited by its retrospective nature and its small sample size.