Heart failure subgroups: HFrEF, HFmrEF, and HFpEF with or without mitral regurgitation.
Lüscher TFEditorial Office, Zurich Heart House, 8032 Zurich, Center for Molecular Cardiology, Schlieren Campus, University of Zurich, Switzerland and Royal Brompton and Harefield Hospital Trust and Imperial College, London, SW3 6NP, UK.