Key result
Prior mitral valve surgery linked to ~270% higher risk of mitral isthmus line ablation failure.
Why the study?
Perimitral flutter and AF after surgical mitral valve repair or replacement are challenging to treat with percutaneous catheter ablation, and the feasibility, acute success, and durability of MIL or AL ablation remained to be determined.
Does catheter ablation using a mitral isthmus line or anterior line achieve acute bidirectional block and long-term durability in patients with prior mitral valve surgery compared to matched controls?
Case-Control (n=162)
Does catheter ablation using a mitral isthmus line or anterior line achieve acute bidirectional block and long-term durability in patients with prior mitral valve surgery compared to matched controls?
Effect estimate: HR 0.27 (95% CI 0.11-0.65)
Absolute Event Rate: 2.224% vs 0.605%
p-value: p=.004
Percutaneous creation of anterior and mitral isthmus lines is feasible in patients with prior mitral valve surgery, though the mitral isthmus line has worse long-term durability compared to patients without prior valve surgery.
May warrant caution using mitral isthmus lines after valve surgery; leaves open optimal lesion sets in this population.
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. 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 reconstruction (n = 51) underwent creation of a MIL (34) and/or an AL (72). RESULTS: Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients. Patients of the control group without prior MV surgery were matched 1:1 with the valve group. In the AL control subgroup, acute bidirectional block was achieved in 65/72 patients. Acute blockage in the MIL control subgroup could be achieved in 31/34 patients. The MIL valve subgroup showed the worst results in terms of durability, whereas a similar trend emerged in the control group and the AL valve subgroup (probability of failure in MIL valve subgroup 2.224 vs. MIL control subgroup 0.605 [Hazard Ratio (HR) = 0.27, 95% confidence interval (CI), 0.11-0.65), P = .004]; 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 = .523]). CONCLUSIONS: Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair and associated with moderate acute and long-term success rates to achieve bidirectional block.
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Bertels et al. (2022) conducted a case-control in Perimitral flutter and atrial fibrillation (n=162). Catheter ablation (mitral isthmus line or anterior line) vs. Matched patients without prior mitral valve surgery was evaluated on Probability of failure of mitral isthmus line (MIL) block (HR 0.27, 95% CI 0.11-0.65, p=.004). Catheter ablation of a mitral isthmus line in patients with prior mitral valve surgery had a higher probability of failure compared to matched controls (control vs valve HR 0.27; 95% CI 0.11-0.65; P=0.004).
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