Atrial natriuretic peptide (ANP) in the plasma of cattle with atrial fibrillation (Af) was investigated. Plasma ANP concentration in the cattle with Af was highly increased (118.0±44.0 (SD) pg/ml, n=5 as compared with that in the control (43.4±5.28 pg/ml, n=12, p<0.05). After defibrillation by oral of administration, quinidine a significant decrease in plasma ANP concentration was observed (41.1±6. 06 pg/ml, p<0.05), the concentration being similar to that in the control. Gel permeation chromatogram of plasma ANP showed a single peak corresponding to the elution position of authentic α-hANP in plasma during Af and after defibrillation. These results indicate that the excretion of ANP from the heart is was enhanced without alteration of the molecular from of ANP.

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This study was performed to assess the effect of an intravenous injection of large doses of penicillin G salt form on serum electrolyte and electrocardiogram in dogs.
Eighteen beagle dogs (age: 8-22 months, body weight: 7-10.5 kg) were given intravenously 3.5×10⁵ I. U./kg and 7×10⁵ I. U./kg of penicillin G potassium or penicillin G sodium. The injection volume was 2.4 ml/kg body weight and the injection speed was 4-5 ml/min.
During the intravenous injection of 7×10⁵ I. U./1. 2 mEq (equivalent to K⁺+)/kg of penicillin G potassium, vomiting and convulsion were observed, and an elevation of T waves, a prolongation of QRS complex and a depression of ST segment were noted on the electrocardiogram. The injection was obliged to be stopped in 2 out of 4 dogs, since these 2 dogs showed the disappearance of P wave 3-4 min after the onset of injection.
On the other hand, during the intravenous injection of 7×10⁵ I. U./1.2 mEq (equivalent to Na⁺+)/kg of penicillin G sodium, vomiting only was observed, and changes in ECG were smaller as compared with those induced by penicillin G potassium.
Changes in serum K⁺ and Na⁺+ concentration after injection of penicillin G potassium or penicillin G sodium remained within the normal range.
The changes during and after the intravenous administration of penicillin G potassium and penicillin G sodium were very similar qualitatively and quantitatively to those induced by the equivalent dosing of KCl and NaCl.
From the foregoing results it is concluded that the cardiac effects of penicillin G potassium or sodium are mainly due to those K⁺ or Na⁺ contained in them, and that penicillin G sodium is safer in clinical use than penicillin G potassium.

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The authors have developed a restraining device which allows the operator to record electrocardiograms (ECGs) of the rat under the non-anesthetic condition.
This device enables the operator to hold a rat for 30-60 seconds without any anesthetics, to attach the electrodes easily to the four limbs and to perform long-term recording of stable ECGs.
The size of this device is 615(W)×220(D)×191(H) mm, the weight is 3.0 kg, and the composing materials are polyacctal resin and stainless steel. Being strong against medicines and boiled water, this device can be fit for any sterilization procedures. Furthermore, the range of the body weights of rats to be held with this device can be widened from 200 g to 650 g, by adjustment of its holding parts. For these reasons, an operator alone, without any assistants can record the ECGs of rats under the non-anesthetic condition.

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We have developed an autoanalyzing electrocardiograph for rats and mice. This unit is not only capable of measuring the electrocardiograms of rats and mice, but also capable of storing and managing the data in various ways by connection this unit with a personal computer.
The sampling rate of this unit is 2, 400 Hz and the frequency response is 500 Hz-3 dB, and its measurable upper limit of heart rate is 1, 000 BPM. This unit prepares two recording modes in harmony with usage; one mode is a continuous recording and the other is an intermittent recording. The countinuous recording mode memorizes 10-second waveforms and prints them out countinuously, exercising a power to find arthmias. The intermittent recording mode reads 1-second waveforms and performs automeasurement of each ECG element. Prior to the automeasurement, some noises are eliminated by the adding average method.
As a result of testing this unit in 100 cases each for rats and mice, its automeasurement accuracy was quite favorable, except for those ECGs which had extermely low voltages or remarkable noises.
Also we have made nickel silver clip-type electrodes nsable exclusively for rats and mice. The weight is 1. 5 grams each.

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A 4-month-old female mongrel puppy was presented with an anophthalmos. On physical examination, systolic murmur was heard at the 4th left intercostal space near the sternum. However the dog appeared healthy without cyanosis and had no history of exercise intolerance.
The phonocardiogram revealed a pansystolic murmur and a continuous murmur on the mitral area. A systolic ejection murmur was also recorded on the pulmonic area. The electrocardiogram indicated bi-ventricular hypertrophy. Left ventricular enlargement was seen on chest radiographs. Ventricular septal defect (VSD) and patent ductus arteriosus (PDA) were diagnosed from these findings. PDA closure was performed at 2 years of age. After 2 months from the operation, the dog died during an attempted repair of the VSD.
At necropsy, it was found that the double-chambered right ventricle (DCRV) was formed by an anomalous septal band. The VSD was localized on the proximal conus and was 8 mm in diameter.

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A 15-month-old male boxer dog weighing 22 kg was referred to Azabu University Animal Hospital for evaluation of the syncopal attack.
There was no cardiac murmur, but electrocardiograms revealed an atrial fibrillation.
Thoracic radiograph revealed enlargement of the right and left atrial regions.
The medical treatment with digitalis and captopril was made for conversion from the atrial fibrillation to the sinus rhythm.
By cardiac catheterization, atrial and ventricular septal defect with pulmonary stenosis was demonstrated.
The patient died at 20 months from the first medical examination. At autopsy, there were severe enlargement of both atria, atrial defect, and pulmonary and tricuspid valvular anomalies.

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