"Predictors of Long-Term Outcomes in Patients with Significant Myxomatous Mitral Regurgitation Undergoing Exercise Echocardiography"  
Circ  
http://circ.ahajournals.org/content/early/2014/01/03/CIRCULATIONAHA.113.005287.abstract 
"Conclusions—In patients with ≥III+ myxomatous MR undergoing ExEc, lower %age-gender predicted METS, lower HRR, atrial fibrillation, lower LV ejection fraction and high resting RVSP predicted worse outcomes."