ELECTROCARDIOGRAPHIC EVALUATION IN PREGNANT MARES AND NEONATE FOALS OF PAINT HORSE BREED

Resumo

For the interpretation and evaluation of electrocardiography, it is necessary to know the species’ electrocardiographic patterns, as well as the breed and age of the animal. The objective of this study was to describe the electrocardiographic characteristics in neonate foals of Paint Horse breed and in clinically normal pregnant mares. We evaluated 20 animals of each category. The maternal electrocardiographic examinations were performed at 15 and 7 days preterm; the neonatal echocardiographic examinations were performed at birth up to 48 hours postpartum, and thereafter once a week up to 35 days of age. For each electrocardiographic record, the heart rate (HR), cardiac electrical axis, rhythm alterations, wave lengths and amplitudes, and electrocardiographic intervals were analyzed. During the first 48 hours of life of the equine neonate, sinus tachycardia and ventricular arrhythmias were observed. In foals during the first month of age, a predominance of sinus rhythm was observed, with a decrease in HR and R-wave amplitude, and an increase in PR, QT, and RR intervals over the course of days. In pregnant mares, no significant changes were found in the electrocardiographic tracings when compared to that of healthy adult horses. The results of this study demonstrated the influence of age and growth on electrocardiographic parameters.