Abstract
Doppler echocardiographic examinations are an important technique for evaluating the blood flow also in avian cardiology. The influence of anaesthesia on the blood flow in the heart is in detail unknown for most avian species. The present study investigated the influence of an isoflurane anaesthesia on the systolic blood flow of the aorta and the pulmonary artery in the area of the heart valves examined by pulsed wave Doppler sonography in Racing Pigeons (Columba livia f. domestica, n = 43). Measurements were taken in conscious and anaesthetised birds in the left (aorta) and right (pulmonary artery) parasternal longitudinal horizontal heart view. The results demonstrated a significant decrease in heart rate and systolic peak flow velocities as well as prolonged ejection times during anaesthesia. A positive correlation of systolic peak flow velocity and heart rate could be demonstrated, especially for the pulmonary artery in conscious pigeons. The aortic systolic peak flow velocity and heart rate showed a significantly negative correlation in anaesthetised pigeons. These correlations should be borne in mind in the echocardiographic examination, especially of conscious birds. A higher incidence of second degree atrioventricular block (30.23%) was induced by anaesthesia in the Racing Pigeons. These results of the present study indicate the necessity for establishing normal heart values in conscious and anaesthetised individuals.

Key words: Sonography, Aorta, Pulmonary artery, Blood flow velocity, Birds