In fibroelastic deficiency the mitral annulus is dilated by chronic regurgitation, widening the valvular area and this may induce a quite large (quadrangular, dashed lines) resection;      
  Part of: Cirillo M (2020) Ring-first Mitral Valve Repair. Research Ideas and Outcomes 6: e62369. https://doi.org/10.3897/rio.6.e62369