Cardiopulmonary exercise testing augments watchful waiting in asymptomatic severe primary mitral regurgitation.

INTRODUCTION: Our aim is to describe the use of cardiopulmonary exercise testing in watchful waiting for asymptomatic severe primary mitral regurgitation. METHODS: Between October 2016 and October 2017, ten patients with asymptomatic severe primary mitral regurgitation underwent watchful waiting in a single centre. Baseline assessment included history, physical examination, transthoracic echocardiogram and cardiopulmonary exercise testing. Patients were re-evaluated every 6 months with history, physical examination and transthoracic echocardiogram; and at 12 months with cardiopulmonary exercise testing. RESULTS: At 1 year follow up, five patients remained asymptomatic with no significant change in left ventricular ejection fraction (p = 0.18). This was associated with no significant change in cardiopulmonary exercise testing parameters. However, five patients developed early new symptoms or changes in echocardiographic parameters with a significant fall in left ventricular ejection fraction (p < 0.01). This was associated with a significant fall in anaerobic threshold (p = 0.04) and four of the five patients having an abnormal percentage predicted peak VO2 at 1 year follow up. CONCLUSIONS: Changes in symptomatic status or echocardiographic parameters during a watchful waiting approach for asymptomatic severe primary mitral regurgitation is associated with a significant reduction in cardiopulmonary exercise testing parameters.