Impact of dynamic mitral regurgitation on functional capacity in heart failure

Introduction: In heart failure reduced ejection fraction (HFrEF) patients the severity of mitral regurgitation (MR) at rest has a well-established prognostic value. MR increase during exercise further adds to an increased risk. MR plays a central role in determining pulmonary flow overload and pulmonary hypertension (PH), which is associated with poor prognosis. Hypothesis: Our aim was to define the relationship between dynamic MR, echocardiographic phenotypes and functional capacity in a cohort of HFrEF patients. Methods: 102 HFrEF patients (age 65±11; male 71%; ischemic etiology 60%; EF 33±9%; NYHA class I, II, III and IV 21, 34, 36, 9%) underwent cardiopulmonary exercise test (CPET) on tiltable cycle-ergometer (standard incremental ramp protocol) combined with exercise-echocardiography. The population was studied according to the degree of functional MR and data were analyzed looking at CPET- and echo-derived phenotypes. Results: Study population was divided into three groups according to the degree of functional MR: rest and peak exercise ERO<20 mm2 (Group A); rest ERO<20 mm2 and peak ERO≥20 mm2 (dynamic MR, Group B); rest ERO≥20 mm2 (Group C). The latter group hadhigher resting and peak exercise pulmonary pressure (PAP), an impaired RV systolic function and ventilatory efficiency. Group B patients exhibited a worse exercise response (lower peak VO2 and workload), more advanced cardiac remodeling and higher pulmonary artery systolic pressure (SPAP) compared to Group A, despite similar LVEF. Conclusions: Dynamic MR is an intermediate condition of the functional MR in HFrEF patients. Exercise-induced MR is associated with a worse CPET phenotype, more unfavorable cardiac chambers remodeling, severe diastolic dysfunction, dynamic PHand RV dysfunction. A combined approach with CPET and echocardiographic assessment can help to early unmask and treatfunctional dynamic MR and its unfavorable phenotypes.