Significant functional mitral regurgitation affects left atrial function in heart failure patients: haemodynamic correlations and prognostic implications

AIMS: Functional mitral regurgitation (FMR) is a well-known pathophysiological factor in heart failure (HF) patients, and left atrial function (LAF) is a novel determinant of clinical status and outcome in this setting. However, little is known about the pathophysiological role of FMR on LAF in HFrEF patients. Aim of this study is to explore the possible interplay between the severity of FMR and LAF in heart failure with reduce ejection fraction (HFrEF) patients and their possible consequences. METHODS AND RESULTS: We studied 97 consecutive patients with FMR classified in two groups: mild-to-moderate MR ore less (FMR group, n = 38) and moderate-to-severe or more (SFMR group, n = 59). Using the phasic method, left atrial contractile, conduit, reservoir, and total emptying function (TLAEF) were calculated to assess LAF. SFMR group showed significantly lower values of LAF compared to FMR group. LA dysfunction (LA-dys) was defined for TLAEF values below the median and groups divided in four subgroups based on its presence. Patient with LA-Dys in SFMR group showed a worse clinical status, higher incidence of right ventricular dysfunction (RV-Dys), and pulmonary hypertension (PH), and a significant worse clinical survival compared to all other groups. CONCLUSION: In our study, the survival was significantly lower in SFMR/LA-Dys+ group. Furthermore, LA-Dys was strongly related with worse clinical status and higher incidence of PH and RV-Dys. These results suggest that in patients with SFMR and HFrEF, LA-Dys may represent both a marker of more advanced disease and a novel prognostic factor.