REVIEW ARTICLE Atrial Fibrillation and Mitral Valve Repair ANGELIKA JOVIN, M.D.,*‡ DANA A. OPREA, M.D.,† ION S. JOVIN, M.D.,† SABET W. HASHIM, M.D.,‡ and JUDE F. CLANCY, M.D.† From the *Harbor Medical Associates, Clinton, †Department of Medicine, and ‡Department of Surgery, Yale University, New Haven, Connecticut Atrial fibrillation (AF) is present in 30–40% of patients presenting for mitral valve surgery. In patients undergoing mitral valve repair, the presence of AF may be associated with increased mortality and mor- bidity and this is also the case in patients in whom AF persists postoperatively. Advances in understanding the pathogenesis of AF led to techniques that include both mitral valve repair and ablation of AF. The concomitant surgical treatment of AF during mitral surgery has become a commonly performed proce- dure, which was shown to be safe and which may improve the outcome for patients. AF after mitral valve replacement is an accepted indication for anticoagulation, but the data supporting anticoagulation in pa- tients after mitral valve repair who convert to sinus rhythm are sparse. This article reviews the available data regarding outcomes of mitral repair and how they are influenced by AF and its therapy. (PACE 2008; 31:1057–1063) atrial fibrillation, mitral valve, mitral regurgitation, mitral repair, anticoagulation Atrial Fibrillation Atrial fibrillation (AF) is characterized by rapid and irregular activation of the atrium. It may be recurrent (paroxysmal) or permanent (chronic). 1 During AF, atrial cells fire at rates of 400–600 times per minute. The filtering function of the atrioventricular node prevents the conduc- tion to the ventricles and therefore results in in- effective cardiac contraction. 2 The overall preva- lence of AF in the population is increasing. The occurrence of AF increases with age, gender, and underlying disease. The incidence of AF doubles with each decade of adult life. Diabetes, hyperten- sion, congestive heart failure, and valve disease are significantly associated with increased risk for AF in both sexes. 3 AF is associated with the loss of the atrial con- tribution to ventricular filling. This may result in a decrease in ventricular stroke volume and hemo- dynamic impairment. 4 If the patient is hemody- namically unstable electrical cardioversion is rec- ommended. Restoration of sinus rhythm (SR) is also considered when the patient is symptomatic despite rate control. Otherwise, rate control is an acceptable alternative. 5,6 Only 20% to 30% of pa- tients who are successfully cardioverted maintain SR for more than 1 year without chronic antiar- rhythmic therapy. 7–9 Address for reprints: Ion S. Jovin, M.D., Department of Medicine/Cardiology, Virginia Commonwealth University, 1201 Broad Rock Blvd 4D/111J1, Richmond, VA 23249. Fax: +1-804-6755337; e-mail: isjovin@yahoo.com Received December 21, 2007; revised April 21, 2008; accepted April 24, 2008. The application of radiofrequency energy at the site of ectopic foci within the pulmonary veins or the electrical isolation of the pulmonary vein from the atrium leads to a reduction in sponta- neous atrial ectopy and the abolition of AF in certain populations. 10 The maze procedure, intro- duced 1987 by Cox and colleagues, is a surgical procedure in which the atrial appendages are ex- cised and the pulmonary veins are isolated. The incisions are placed so that the critical atrial mass necessary to sustain multiple reentrant circuits and thus AF cannot occur. Several dead-end al- leyways create maze-like pathways and permit the depolarization of all the atrial tissue, in an attempt to maintain mechanical contraction. 11 A modified maze procedure, which also better preserves atrial function, is more commonly used nowadays, be- cause of the requirement of cardiopulmonary by- pass and a chronotropic as well as technical issues with of the initial maze procedures. 12 The sinus node, a strip of atrial tissue, and the atrioventric- ular node are isolated from the rest of the atria. While allowing SR to be sustained this does not reestablish atrial transport or atrioventricular syn- chrony, like the maze operation. 2,8,11 The surgical therapy of AF, especially in the setting of mitral operations, has been recently reviewed. 13–15 Im- plantable defibrillators can be programmed to ter- minate AF by means of an internal shock in se- lected patients. 4,16,17 Systemic embolization in the setting of parox- ysmal or chronic AF, spontaneously or in associa- tion with cardioversion, results in increased stroke severity and a greater mortality rate than in non- AF strokes. 18 Warfarin with a goal international normalized ratio of 2–3 is the treatment of choice C 2008, The Authors. Journal compilation C 2008, Blackwell Publishing, Inc. PACE, Vol. 31 August 2008 1057