[Variations in electrocardiogram QRS-T (author's transl)].

The variations in QRS-T configurations in both standard and precordial leads from control rat electrocardiograms are analysed in this study. The durations of the above mentioned QRS complex, T and Q waves and the QT interval are also described. Many of the observed differences in rat electrocardiograms are due to a series of factors that may include recording equipment, anaesthesia used, dorsal or ventral position of the animal, age weight, sex and litter. The influence of all these parameters has been taken into account in the course of this research work. The electrocardiograms shown in this work were carried out as part of a project in which these patterns would later be compared with those obtained from rats in which ischemia has been induced by means of isoproterenol.