Comparison of early surgery versus con- ventional treatment in asymptomatic severe mitral regurgitation. Circula- tion. 2009;119:797 804. 5. Bonow RO. Chronic mitral regurgitation and aortic regurgitation: have indications for surgery changed? J Am Coll Cardiol. 2013;61:693 701. 6. Enriquez-Sarano M, Avierinos J-F, Messika-Zeitoun D, et al. Quantitative determinants of the outcome of asymptomatic mitral regurgitation. N Engl J Med. 2005;352:875 83. 7. Rosenhek R, Rader F, Klaar U, et al. Outcome of watchful waiting in as- ymptomatic severe mitral regurgitation. Circulation. 2006;113:2238 44. 8. Grigioni F, Tribouilloy C, Avierinos JF, et al. Outcomes in mitral regurgita- tion due to flail leaflets a multicenter European study. JACC Cardiovasc Imaging. 2008;1:133 41. 9. Kang D-H, Park S-J, Sun BJ, et al. Early surgery versus conventional treat- ment for asymptomatic severe mitral regurgitation: a propensity analysis. J Am Coll Cardiol. 2014;63:2398 407. 10. Rosen SE, Borer JS, Hochreiter C, et al. Natural history of the asymp- tomatic/minimally symptomatic patient with severe mitral regurgitation secondary to mitral valve prolapse and normal right and left ventricular performance. Am J Cardiol. 1994;74:374 80. 11. Qui ones MA, Douglas PS, Foster E, et al. American College of Cardiology/ American Heart Association clinical competence statement on echocardiog- raphy: a report of the American College of Cardiology/American Heart As- sociation/American College of Physicians American Society of Internal Medicine Task Force on Clinical Competence. Developed in collaboration with the American Society of Echocardiography, the Society of Cardiovascular Anesthesiologists, and the Society of Pediatric Echocardiography. Circulation. 2003;107:1068 89. 12. Detaint D, Messika-Zeitoun D, Avierinos J-F, et al. B-type natriuretic pep- tide in organic mitral regurgitation: determinants and impact on outcome. Circulation. 2005;111:2391 7. 13. Sutton TM, Stewart RAH, Gerber IL, et al. Plasma natriuretic peptide levels increase with symptoms and severity of mitral regurgitation. J Am Coll Cardiol. 2003;41:2280 7. 14. 