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Dokko et al. Vessel Plus 2022;6:37 https://dx.doi.org/10.20517/2574-1209.2021.121 Page 3 of 21

regurgitation globally. In patients with degenerative mitral regurgitation, between 32% to 45% present with
[35]
[2-4]
atrial fibrillation . Kim et al. ’ recent study of ten-year trends in Korea further showed that 66.1% of
patients with mitral stenosis had atrial fibrillation. Patients with atrial fibrillation and mitral disease were
[2-4]
often older, presenting with more severe mitral disease and LA and left ventricular enlargement . Thus,
atrial fibrillation represents one of the most prevalent diseases occurring concomitant with MV repair and
replacement procedures.

Therapeutic interventions
Due to increased mortality risk from stroke, thromboembolic events and other adverse outcomes associated
with pre-operative atrial fibrillation, treatment for patients with pre-operative atrial fibrillation and MV
disease is focused primarily on preventing these complications through anticoagulation, medical rate and
rhythm control, and ablation procedures when medical therapy is not sufficient [36-39] .

Medical therapy
According to the 2020 ACC/AHA guidelines, to prevent stroke and other thromboembolic events, non-
vitamin K oral anticoagulants are recommended for patients with atrial fibrillation and nonrheumatic mitral
stenosis or mitral disease (Class I, Level A). Patients with rheumatic mitral stenosis and atrial fibrillation
should be given long-term vitamin K antagonist oral anticoagulants (Class I, Level C-EO) . Recent studies
[36]
have shown increased use of direct oral anticoagulants in patients with atrial fibrillation undergoing MV
procedures [40,41] . Several meta-analyses demonstrate decreased risk of stroke and systemic embolism [42-44] and
decreased risk of major bleeding with edoxaban , apixaban and dabigatran . Furthermore, a recent
[43]
[42]
randomized controlled trial in patients with atrial fibrillation and mitral or aortic valve disease showed a
non-significant trend towards reduced stroke, systemic embolism, death, and major bleeding with apixaban
[45]
compared to warfarin . However, additional research appears warranted to conclusively determine the
superiority of direct oral anticoagulants vs. vitamin K antagonists .
[43]
Additional 2020 ACC/AHA guidelines on valvular heart disease recommend that patients with rheumatic
mitral stenosis and acute atrial fibrillation should be treated with negative dromotropic agents to slow
ventricular contraction and decrease left atrial pressure (Class 2A, Level C-LD) . Rate control therapy has
[36]
been shown to have similar efficacy in conjunction with anticoagulation in controlling adverse outcomes
compared to rhythm control therapy; it is recommended by the 2014 ACC/AHA/HRS guidelines on atrial
fibrillation to address the symptoms of atrial fibrillation, improve the quality of life and reduce
morbidity [37,46-52] . Rate control therapy can be used in patients with paroxysmal, persistent or permanent
atrial fibrillation (Class I, Level B) [37,46] . Beta blockers are used most frequently, followed by
nondihydropyridine calcium channel blockers, digoxin or amiodarone . However, if atrial fibrillation
[37]
persists with worsening symptoms despite rate control and anticoagulation therapy, antiarrhythmic drugs,
such as amiodarone, may be recommended to alleviate the symptoms of atrial fibrillation (Class I, Level
C) [37,46] .

Ablation
Ablation procedures can be performed through a surgical or transcatheter approach. Surgical ablations are
often performed concomitantly with MV surgery to improve patient outcomes, restore sinus rhythm, and
reduce the need for long-term use of anticoagulants and antiarrhythmic drugs [2,53-58] . According to the STS
guidelines, concomitant surgical ablation is a Class I, Level A recommendation for patients undergoing MV
surgery with pre-operative atrial fibrillation due to its effectiveness in restoring sinus rhythm without
[53]
increased operative morbidity and mortality . Surgical ablation involves creating lesions in the right and
left atria, most commonly around the pulmonary veins, to disrupt the electrical conduction pathways of