The Electrocardiographic Studies in Rhesus Monkeys (Macaca mulatta)

Abstract

Electrocardiograms were recorded in 17 female Rhesus monkeys 4-7 years old weighing 3.5-7.5 kg by the unipolar lead from the thoracic area on the body surface. Distributions of wave forms and potentials of the QRS complex were discussed electrocardiographically on the basis of the relative position of the heart in the thoracic cavity.
1. The minus and the plus pole of the QRS complex which had been calculated from unipolar electrocardiograms were placed in the right frontal and the left rear part of the thorax respectively. A transitional zone was described obliquely from the left axilla to the lower right part of the thorax. The pattern of the QRS complex showed the rS or QS type on the minus zone and the Rs or qR type on the plus zone.
2. The position of the electrode in A-B lead speculated from unipolar electrocardiograms was the same as reported by Uchino et al. in Macaca fuscata. It was also considered to be suitable for the anatomical observation of the heart in the thoracic cavity.
3. Six unipolar lead positions were indicated from the results obtained on the relationship between the positions of both nipples and ventricles. It was assumed that the above-mentioned lead method might be applicable at least to Macaca monkeys.