To examine vectorcardiography of left ventricular hypertrophy (LVH) in a spontaneously hypertensive rat (SHR), vectorcardiogram (VCG) was recorded from ten 30-week-old SHRs and ten age-matched Wistar rats (WR) by applying McFee-Parungao lead system for the dog.
Arterial blood pressure (BP) was 113.25±11.83mmHg in WR and 188.43±19.17 mmHg in SHR. VCG was recorded by McFee-Parungao lead system in restrained ventral position after being anesthetized with urethan-chloralose. VCG was measured on the following parameters; orientation, magnitude and time of maximum QRS vector (Max QRSv), orientation and magnitude of maximum T vector (Max Tv), QRS-T angle and ratio of T/QRS.
VCG in SHR was characterized by superior, posterior and leftward shift of QRS loop, prolongation of time of Max QRSv, and an increase of QRS-T angle in all planes. These observations of VCG in SHR were very similar to those of LVH due to pressure overloading in humans.

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Electrocardiography during the first 90 days of life was studied in 17 beagle puppies. They were from parents without a history of heart disease. Electrocardiograms were recorded by standard limb leads (I, II, III) and augmented unipolar limb leads (aVR, aVL, aVF). Two of the 17 the puppies were excluded from the results because of the findings markedly different from those of the other puppies.
1) Heart rate increased gradually to around 200 by the 30-40th day and then decreased to around 150 on the 90th day.
2) The variation of P wave voltage was not recorded until the 90th day, but T wave voltage tended to increase gradually until the 40th day of life, and then to decrease until the 90th day.
3) The R/S ratio in the II lead increased from less than 1.0 at birth to more than 2.0 on the 25th day.
4) QRS complex in each leads indicated the same wave pattern as in adult dogs around the second week of life.
5) The QRS modal axis changed from a leftward and cranial (+133.5°-160.8°, av.-136.5°) at birth to a rightward and ventral orientation (+19.8°-+101.4°, av.+52.9°) on the 90th day.

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Changes in electrical axis and type of QRS complex in the electrocardiogram wese studied in 7 heifers with right ventricular, 2 cows with left ventricular hypertrophy, 11 normal heifers and 24 dairy cows. The standard limb lead was not suitable for calculation of electrical axis in cattle. The electrical axis by Sugeno's bipolar chest lead (sagittal plane) and CV6RU-CV₆LU-CV₆LL bipolar chest lead (transverse plane) was obtained. There was a correlation between the electrical axis and half-area vector of vectorcardiogram. Right ventricular hypertrophy was observed by the negative high voltage in the AB lead QRS complex, the right shift of the electrical axis of QRS complex in transverse plane, the negative high voltage of CV₆LL and CV₆LU leads, the negative or positive high voltage of the CV₆RL lead and the positive high voltage of the CV₆RU lead. Similarly, left ventricular hypertrophy was observed by the positive high voltage in the AB lead QRS complex, the tail shift of the electrical axis of QRS complex on sagittal plane, the left shift of the electrical axis of QRS complex on transverse plane, the positive high voltage of CV₆LL and CV₆LU leads and the positive or negative high voltage of CV₆RL and CV₆RU leads. The AB lead QRS interval in the animal with ventricular hypertrophy did not prolong, as compared with those in heifers and dairy cows. There was no difference in the electrical axis between heifers and dairy cows.

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Double outlet right ventricle (DORV) was observed in 15 (13.9%) of 108 bovine hearts showing congenital cardiac anomalies, and the incidence of that was much higher than those reported in man and other animals.
These cases and other reported bovine DORV were classified depending on the presence or absence of ventricular septal defect (VSD) and anatomical position of VSD. Each type of DORV in cattle was compared in incidence with that in man. DORV with subaortic VSD was the most common type in cattle as was in man. In cattle, however, the incidences of intact ventricular septum type and that of noncommitted VSD type were higher than those in man.

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A 4-year-old Arabian mare, which had the mitral regurgitation with atrial fibrillation and the chronic hepatic dysfunction, was examined by ultrasound imaging.
M-mode and two-dimensional (linear scan) echocardiography revealed the mitral valve thickening and prolapse, the B-B' step formation on the M-mode mitral valve echogram, the dilatation of four cardiac chambers, and hyperkinetics of ventricular walls. Contrast echocardiography demonstrated the secondary tricuspid regurgitation. On the M-mode phonoechocardiogram, the third heart sound coincided in time with the points of inflexion (check points) of ventricular walls.
Abdominal sonographic examination demonstrated hepatic enlargement and congestion with the dull edge and dilated hepatic vein, and the bloody ascites with fine echoes. Hepatic fibrotic lesions caused by “intrahepatic cholangiocellular fibroadenomatosis” were imaged as a high echo amplitude area with the wave-like surface of the liver. Histogram analysis was also conducted.

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The pharmacokinetics of quinidine was studied by using 12 diseased cows after oral or intravenous administration of this drug. Plasma and major body tissue concentrations the of quinidine were quantitatively analyzed postmortem by the double extraction method. A series of oral doses with decreasing dosage were most effective in maintaining the therapeutic plasma concentrations and thus considered to be the safest. Since there was a correlation between myocardium and plasma concentrations of quinidine (r=0.768), it might be possible to estimate the myocardial concentration of this drug from its plasma concentration. After intravenous or oral administration, quinidine was detected in the brain, suggesting that it might be associated with development of cinchonism as an immediate cause. In a pregnant cow, orally administered quinidine was found in the fetus, suggesting a transplacental transfer of this drug.

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