The Spatial Vectorcardiogram and Mean Spatial Ventricular Gradient in Normal Pregnant Women
The spatial vectorcardiogram and the spatial ventricular gradient of normal subjects in the last trimester of pregnancy and in some of the same subjects following delivery have been studied. It was found that the vectorcardiograms could be divided into two groups on the basis of the form of the QRS sÊ-loops, as has been previously reported for other normal subjects. In some instances records taken after delivery or records taken during pregnancy with the subject in deep inspiration altered both the orientation and the form of the QRS sÊ-loop. Since these alterations were most likely due to changes in position of the heart and extracardiac tissues, it is suggested that these are factors determining the configurations of the two types of normal QRS sÊ-loops.
- © 1954 American Heart Association, Inc.