Vectorcardiographical and electrocardiographical findings were comparatively studied in spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WK). The angle of maximum QRS vector in the frontal plane reflects in the electrical axis in electrocardiogram(ECG), and ST-T changes in vectorcardiogram (VCG) which were also observed as ST-T depression in X scalar ECG were related to the ST-T depression in left
chest leads.
The topographical location of the heart was examined in the transverse section of the chest of 10-month-old stroke-prone SHR (SHRSP)immediately frozen in acetone-dry ice mixture and a comparison was made with age-matched WK. The clockwise rotation of the heart thus proven in SHRSP appeared to be related to such vectorcardiographical findings as the left superior deviation of major QRS portion.
From these results also, the heart of SHR was ascertained to be a good basic model for hypertensive cardiac diseases in humans.