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Implications of Atrial Fibrillation in Degenerative Mitral Regurgitation
Study Questions:
What are the prognostic and therapeutic implications of atrial fibrillation (AF) at the time of diagnosis of degenerative mitral regurgitation (MR), and longer-term?
Methods:
The MIDA (Mitral Regurgitation International Database) registry is an international registry that merges prospectively collected electronic institutional data among patients who underwent echocardiography at enrolling centers in North America and Europe between 1980 and 2005 and had degenerative MR diagnosed by mitral leaflet flail. Patients with concomitant aortic disease, mitral stenosis, active endocarditis, congenital diseases, and previous valve surgery were excluded. This study evaluated patients in the registry with an electrocardiogram demonstrating either sinus rhythm or AF.
Results:
Among 2,425 patients (age 67 ± 13 years, 71% male, 67% asymptomatic, ejection fraction [EF] 64 ± 10%), 1,646 presented at diagnosis with sinus rhythm (SR), 317 with paroxysmal AF, and 462 with persistent AF. Baseline clinical (older age, higher prevalence of diabetes, greater use of diuretic medications, lower prevalence of asymptomatic status) and echocardiographic characteristics (larger left atrial [LA] and left ventricular [LV] diameters, lower LVEF) were progressively worse from SR to paroxysmal AF to persistent AF. During follow-up, paroxysmal and persistent AF were associated with excess mortality (10-year survival in SR and in paroxysmal and persistent AF was 74 ± 1%, 59 ± 3%, and 46 ± 2%, respectively; p < 0.0001), that persisted 20 years after diagnosis and independently of other baseline characteristics (p values < 0.0001). Surgery (n = 1,889; repair 88%) was associated with better survival compared to medical management regardless of baseline characteristics and rhythm (adjusted hazard ratio, 0.26; 95% confidence interval, 0.23-0.30; p < 0.0001), but post-surgical outcome remained affected by AF (10-year post-surgical survival in SR and in paroxysmal and persistent AF was 82 ± 1%, 70 ± 4%, and 57 ± 3%, respectively; p < 0.0001).
Conclusions:
AF is a frequent occurrence at the time of diagnosis of degenerative MR. Although AF was associated with older age and more advanced presentation of MR, it was independently associated with excess mortality long-termer after diagnosis. Surgery was associated with improved survival in each cardiac rhythm subset, but a persistence of excess risk was observed for each type of AF. The authors concluded that the detection of AF, even paroxysmal, should trigger prompt consideration for surgery.
Perspective:
The current American Heart Association/American College of Cardiology valvular heart disease guideline considers as reasonable (Class IIa, Level of Evidence B) referral for mitral valve repair of asymptomatic patients with chronic, severe, nonrheumatic primary MR, preserved LV function, a high likelihood of successful and durable repair, and new-onset AF; based on the hope that restoration of mitral competence might lead to reduced LA size and maintenance of SR. The present study is a retrospective review that finds an association between AF and adverse outcomes with or without surgical intervention. Prospective, randomized data are necessary to address whether the adverse outcomes associated with AF are favorably and independently modified by surgical intervention.
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Cardiac Surgical Procedures, Diabetes Mellitus, Diuretics, Echocardiography, Electrocardiography, Heart Valve Diseases, Mitral Valve Insufficiency, Treatment Outcome
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