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Page 14 of 21 Dokko et al. Vessel Plus 2022;6:37 https://dx.doi.org/10.20517/2574-1209.2021.121

[137]
surgeons more likely to perform the procedure . The risk and benefit of concomitant surgical ablation are
patient and surgeon dependent and more time is needed to evaluate the long-term outcomes of
concomitant surgical ablation before it can be expanded for prophylactic use in patients who are in sinus
rhythm but at risk for POAF. However, prophylactic ablation is promising, especially due to the high
likelihood of developing POAF after MV surgery and may likely become standard therapy for these
patients. For prophylactic ablation to be considered, it will be critical to identify risk factors in patients that
predict specifically persistent POAF and compare its efficacy to prophylactic medical therapy in
combination and alone [127,128] . Other important prophylactic therapy to consider are routine concomitant
LAA closure for all patients undergoing MV surgery and transcatheter ablation prior to MV surgery for
patients with pre-operative atrial fibrillation as a less invasive alternative procedure to concomitant surgical
ablation.

Thrombi from atrial fibrillation are most commonly found in the LAA, and its surgical closure may reduce
[138]
the risk of stroke and the need for life-long anticoagulation. Ando et al. conducted a meta-analysis
evaluating the impact of LAA closure in patients undergoing cardiac surgery and observed lower 30-day or
in-hospital mortality and incidence of cerebrovascular accidents in patients who underwent LAA closure,
especially in patients with pre-operative atrial fibrillation. A weaker association was seen in patients without
[138]
pre-operative atrial fibrillation undergoing valve surgery . Due to the high risk of POAF and associated
increased risk of stroke in patients undergoing MV surgery, prophylactic LAA for all patients undergoing
MV surgery may be a promising beneficial therapy.

Transcatheter ablation may also serve as a less invasive and intensive alternative procedure to concomitant
surgical ablation in patients with pre-operative atrial fibrillation undergoing MV surgery. Concomitant
surgical ablation lengthens the MV surgery, may require longer bypass time and is associated with
permanent pacemaker implantation . Previous studies with transcatheter ablation have shown successful
[75]
long-term cardioversion albeit requiring repeat ablations [96-98] . Due to its shorter procedural time and less
invasive nature, transcatheter ablation may serve as a safer prophylactic ablative therapy and in combination
with catheter ablation of the cavotricuspid isthmus has been shown in a meta-analysis to reduce the
incidence of atrial fibrillation in patients with atrial flutter .
[139]

CONCLUSION
Both pre- and post-operative atrial fibrillation are common in the MV disease population, yet the reasons
behind the development, optimal treatment, and longer-term impact of these arrhythmic conditions are not
yet completely understood. Pre-operative atrial fibrillation is likely attributable to left atrial enlargement
associated with MV stenosis and regurgitation. If it is by itself a significant risk factor or if it is a surrogate
for impaired myocardium is yet to be determined. Regardless, the management of these high-risk patients
warrants careful consideration. Therapeutic strategies to address pre-operative atrial fibrillation include
medical management and ablation. The etiology of POAF is most likely multifactorial and has been linked
to other pre-operative risks, intra-operative processes of care, as well as surgeon-based experience. Although
there is no consensus regarding the impact of POAF on long-term outcomes, POAF appears to negatively
impact mortality, and thus with more studies would warrant prophylactic therapy through left atrial
appendage closure, transcatheter ablation, or concomitant surgical ablation.

DECLARATIONS
Authors’ contributions
Substantive intellectual contribution, conception, and design: Dokko J, Novotny S, Santore LA, Shroyer
ALW, Bilfinger T