Measurements of mass, length and valve diameters from normal formalin-fixed ovine hearts.

Hearts from 60 Merino sheep of known age, sex and live mass and with no known history of disease were collected and fixed in buffered 10% formalin. Systematic light microscopical examination did not indicate any abnormality in hearts of any of the sheep. The mass of various parts of the hearts, the length of the hearts and the diameters of the heart valves were measured to establish a basis for quantitative assessment of possible pathological changes associated with the ingestion of cardiotoxic plants. The mass measurements and, to a lesser degree, the lengths of the hearts varied considerably, but the ratio of the mass of the left ventricle plus ventricular septum divided by the right ventricular free wall mass was remarkably stable, and is promising as an indicator of right ventricular hypertrophy.