Mrs Smith, 62 years old, is referred for mitral valve replacement (MVR) as a result of long-standing severe mitral regurgitation (MR), now with ventricular dilation. She has had AF for 3 years and has severe left atrial enlargement as seen on transthoracic echocardiogram.
Answer: C. It depends on her ability to tolerate medications and willingness to accept the risk of complications from surgical ablation.
In a study published in the New England Journal of Medicine and presented at the American College of Cardiology Scientific Sessions in March 2015, 260 patients with persistent or long-standing AF requiring MVR were randomized to surgical ablation (either MAZE or simple pulmonary vein isolation [PVI]) or no intervention for AF during their MVR procedure. There was a much higher rate of freedom from AF at 6 and 12 months in the group that received an ablation at the time of MVR vs those with MVR alone (63% vs 29%, P <.001) although this came at the cost of more pacemakers needed (21.5 vs 8.1 cases per 100 patient years, P = .01). Notably, there was no difference in AF burden among the type of surgical ablation done (PVI or MAZE).
Mortality rates, stroke rates, and overall serious adverse events were similar between the ablation/MVR group vs MVR alone. This suggests that AF ablation at the time of MVR might provide an excellent option for decreasing burden of AF, although the patient should be willing to accept a slightly higher risk of complete heart block and pacemaker implantation. The long-term sustainability of being AF-free after ablation was also not reported in this 12-month study, so that remains an open question.
Source: Gillinov AM, Gelijns AC, Parides MK, CTSN Investigators. Surgical ablation of atrial fibrillation during mitral-valve surgery. N Engl J Med. 2015 Mar 16. doi:10.1056/NEJMoa1500528 [Epub ahead of print]. http://www.nejm.org/doi/full/10.1056/NEJMoa1500528