Echocardiography in foals from birth to three months old.

Simultaneous echocardiograms, phonocardiograms and electrocardiograms were performed on 16 foals at the following times after birth: 15 mins, 60 mins, 2, 4, 12, 24, 48 h, four, seven, 14 days and four, eight and 12 weeks. Positive correlations were found between both age and body weight and the following measurements: left ventricular end-diastolic dimension, right ventricular end-diastolic dimension, left atrial dimension and aortic root dimension, posterior left ventricular wall thickness and interventricular septal thickness. Heart rate was negatively correlated with left ventricular electromechanical systole, ejection time and isovolumic contraction time. Means and standard deviations are presented for 29 echocardiographic parameters and the results are discussed against the background of the transitional neonatal circulation.