Recently published work has suggested that mitral valve annuloplasty ring type may affect the development of post-repair mitral stenosis resulting in adverse intracardiac hemodynamics and poor functional status. However, these results have not been comprehensively determined in a systematic manner on a general mitral valve repair population. As well, an underlying mechanism for these findings is not understood.

The investigators hypothesize that mitral valve repair with a complete annuloplasty ring (Carpentier-Edwards Physio II) when compared to repair with a partial annuloplasty ring (Simplici- T) may not necessarily result in elevated mitral gradients consistent with functional mitral stenosis (FMS). Currently no prospective data exists to test the hypothesis that a correctly sized, flexible complete annuloplasty ring has detrimental effects.

As 60% of annuloplasty rings used in surgical repair of degenerative mitral valve disease in North America utilizes one of the many forms of complete flexible rings available, this information is urgently required.

The investigators will evaluate: 1) the effect on mitral valve hemodynamics, 2) changes to mitral annular, valvular and subvalvular structure and function with 3D echocardiography, and 3) the effect on patient functional capacity at 1 year.

If FMS early post repair is a real phenomenon, the investigators hope to better understand the mechanisms through the use of advanced imaging techniques-namely 3D modeling of the mitral valvular apparatus, aortic mitral interactions and LV remodeling.

Inclusion Criteria:

• Mitral regurgitation secondary to degenerative valve disease referred to Prof Tirone David (Co-investigator) will be invited to take part.
• The mitral valve anatomy must be anatomy suitable for repair.
• The patient must be able to perform treadmill exercise echocardiography.
• The patient must be over 18 years of age.

Exclusion Criteria:

• Any presence of life-limiting disease process, for example advanced malignancy.
• Hemodynamically unstable patients in cardiogenic shock
• Concomitant aortic valve disease/surgery
• Previous mitral valve repair
• Impaired left ventricular systolic function as defined by a left ventricular ejection fraction of ≤ 50%.
• If the patient lives out of state or cannot attend follow up visits.