Thermodilution curves for diagnosis of ventricular septal defect in cattle.

An indicator dilution method developed for detection of intracardiac shunts and determination of cardiac output in man and domestic animals was evaluated in 4 calves and 1 cow with holosystolic cardiac murmurs. Thermodilution curves recorded from the pulmonary artery and the right ventricle confirmed a left-to-right intracardiac shunt and provided a means for its quantitation. Ventricular septal defect was confirmed in 2 cows, which were euthanatized. The data obtained by thermodilution were evaluated along with information obtained from other diagnostic procedures (auscultation, oximetry, echocardiography, measurement of intravascular pressures). It was concluded that the procedure is a simple and accurate method for diagnosis of ventricular septal defect in cattle.