TNNI3 and mitral valve insufficiency: hs-cTnI, high-sensitive cardiac troponin I; NYHA, New York Heart Association; NT-proBNP, N-terminal pro-brain natriuretic peptide; LVEF, left ventricular ejection fraction; MR, mitral regurgitation; MV, mitral valve; SV, stroke volume; TR, tricuspid regurgitation; TV, tricuspid valve.