Cats were deemed to be healthy on the basis of clinical examination, cardiac auscultation, non-invasive blood pressure measurement, blood work, and conventional echocardiography (including RV wall thickness in diastole, RV internal diameters in diastole and systole from a short axis view, RV fractional shortening (FS), RV areas in diastole and systole from an apical view, fractional area change, tricuspid annular plane systolic excursion, tissue Doppler imaging derived tricuspid annulus systolic wave velocity, RA maximal and minimal diameters, and RA FS).