Acute and long-term success of left atrial anterior line and mitral isthmus line ablation in patients after mitral valve surgery

Abstract Background Perimitral flutter and atrial fibrillation may occur in patients with prior surgical mitral valve (MV) repair or replacement and can be challenging for percutaneous catheter ablation. Objective This study sought to determine the feasibility, acute success and durability of catheter ablation of atrial fibrillation or atrial tachycardia by way of a mitral isthmus line (MIL) or an anterior line (AL). Methods A total of 81 patients (49 males, mean age 62±11 years) with prior MV replacement (n=30) or repair (n=51) underwent creation of a MIL (n=34) and/or an AL (n=72). Control group patients without prior surgery were matched 1:1 with the valve group (MIL, n=34; AL, n=72). Results Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients with prior MV surgery. In the control group, acute bidirectional block was achieved in 31/34 MIL patients and 65/72 AL patients. In terms of durability, the MIL valve subgroup showed the poorest results (probability of long-term failure 2.224, as opposed to 0.605 in the MIL control subgroup; hazard ratio [HR]=0.27, 95% confidence interval [CI], 0.11–0.65; p=0.004). In the AL subgroups, long-term outcomes were similar (probability of failure in AL valve subgroup 0.844 vs. AL control subgroup 1.03; HR=1.22, 95% CI, 0.66–2.26; p=0.523). Conclusions Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair. Because of poor long-term outcomes, MIL creation appears not advisable in patient with prior MV surgery. Funding Acknowledgement Type of funding sources: None.