Myocardial Fibrosis in Asymptomatic Degenerative Mitral Regurgitation

Degenerative mitral regurgitation (MR), defined as that because of mitral prolapse or flail on the basis of underlying myxomatous disease or fibroelastic deficiency, is common. There is consensus that intervention is appropriate in the setting of symptoms and impaired left ventricular (LV) systolic function as gauged by LV ejection fraction (LVEF) or LV end-systolic volume, and these carry class I recommendations in the current American College of Cardiology/American Heart Association and European Society of Cardiology Guidelines.1,2 There is also support for intervening in the asymptomatic patient with atrial fibrillation or pulmonary hypertension (class II).1,2 However, in the absence of randomized control trials, there is ongoing debate as to the best approach to the management of the patient who meets none of these triggers. Those who advocate close medical follow-up with the use of stress testing to confirm the asymptomatic state until triggers develop (watchful waiting) argue that accurate identification of patients with truly severe degenerative MR can be challenging and that, even in those with unequivocally severe regurgitation, the short- and long-term risks of surgery are not outweighed by the risks of waiting until triggers develop.3 Those who favor prophylactic surgical intervention argue that for patients likely to undergo successful repair, waiting puts them at risk for poorer longer term outcomes.4Article see p 946In an environment where the limitations of LVEF as a measure of systolic function are well recognized, new tools for identifying subclinical abnormalities that might be precursors to overt LVEF reduction or symptoms might prove valuable in clinical decision making. Better still would be a means of reliably identifying the onset of irreversible LV changes of which fibrosis is arguably one.In this issue of Circulation: Cardiovascular Imaging , Edwards et al5 report a study in …