Effect of Body Weight on Echocardiographic Measurements in 19,866 Pure-Bred Cats with or without Heart Disease.

BACKGROUND: Echocardiography is a cost-efficient method to screen cats for presence of heart disease. Current reference intervals for feline cardiac dimensions do not account for body weight (BW). OBJECTIVE: To study the effect of BW on heart rate (HR), aortic (Ao), left atrial (LA) and ventricular (LV) linear dimensions in cats, and to calculate 95% prediction intervals for these variables in normal adult pure-bred cats. ANIMALS: 19 866 pure-bred cats. METHODS: Clinical data from heart screens conducted between 1999 and 2014 were included. Associations between BW, HR, and cardiac dimensions were assessed using univariate linear models and allometric scaling, including all cats, and only those considered normal, respectively. Prediction intervals were created using 95% confidence intervals obtained from regression curves. RESULTS: Associations between BW and echocardiographic dimensions were best described by allometric scaling, and all dimensions increased with increasing BW (all P<0.001). Strongest associations were found between BW and Ao, LV end diastolic, LA dimensions, and thickness of LV free wall. Weak linear associations were found between BW and HR and left atrial to aortic ratio (LA:Ao), for which HR decreased with increasing BW (P<0.001), and LA:Ao increased with increasing BW (P<0.001). Marginal differences were found for prediction formulas and prediction intervals when the dataset included all cats versus only those considered normal. CONCLUSIONS AND IMPORTANCE: BW had a clinically relevant effect on echocardiographic dimensions in cats, and BW based 95% prediction intervals may help in screening cats for heart disease.

Real-time ultrasonography for determining the gestational age of ewes.

Seven Swedish peltsheep ewes were examined weekly by transabdominal ultrasound scanning from one-and-a-half to two months of gestation until parturition. By means of a simple regression analysis, the heart rate, the biparietal diameter of the skull and the diameter of the body trunk were correlated with fetal age, and it was concluded that these measurements could be used to estimate the age of the fetus.

Sedative and analgesic effects of medetomidine in dogs--an open clinical study.

Medetomidine was given parenterally as a sedative and analgesic agent to 283 dogs. Mean doses varied from 17 micrograms/kg for x-ray examinations to 31 micrograms/kg for clinical examinations. An adequate analgesic effect was demonstrated at higher doses than produced sufficient sedation. Potent bradycardia was produced within 15 minutes post administration. No influence of breed, sex or age was found. Vomiting was observed in 8% of the cases. One dog died, showing chronic glomerulonephritis, myocardial necrosis and liver congestion at autopsy.

Effects of medetomidine in dogs with mitral regurgitation.

Thirteen small breed dogs with heart murmurs due to mitral regurgitation of varying severity received medetomidine as a sedative drug for teeth cleaning procedures. The dose was 30 micrograms/kg as an intramuscular injection. The drug caused a considerable reduction of the body temperatures and the heart rates over the 6 hrs of monitoring. The respiratory rates increased over the first 30 min and later decreased below control values. Systolic arterial blood pressures did not change significantly. Arterial oxygen tensions were significantly lower at 30 min after drug administration, but the arteriovenous oxygen differences and the carbon dioxide tensions changed very little. On electrocardiograms, sinus bradycardia, marked sinus arrhythmia with sinus pauses, AV-blocks 1st. and rarely 2nd. degree, supraventricular premature contractions (4 dogs) and paroxysmal tachycardia (1 dog) were observed. Echocardiograms showed an insignificant reduction of the shortening fraction and an increase of the left ventricular enlargement ratio as well as the left atrial to aortic root ratio at 30 min after drug administration. All measured parameters had returned to normal values (pre-drug levels) at 24 hrs after sedation. One dog had delayed cardiovascular complications at 3 hrs after drug administration, (period of prolonged asystole), necessitating the use of the antidote MPV 1248, which successfully reversed the abnormality. Two dogs collapsed briefly, at 4 and 5 hrs respectively, after excitement and struggling against physical restraint. In conclusion, medetomidine will have a safe clinical use for sedation of dogs with murmurs from compensated mitral regurgitation as soon as the antidote MPV 1248 (atipamezole) is licensed for clinical use. This will allow the reversion of the cardiopulmonary effects before the time of expected complications.

Cardiorespiratory and sedative effects of a combination of acepromazine, xylazine and methadone in the horse.

Cardiorespiratory and sedative effects of a combination of acepromazine, xylazine and methadone were studied in the horse. Acepromazine and xylazine produced cardiovascular effects whereas methadone mainly affected respiratory rate. Decreases in heart rate, arterial blood pressure and respiratory rate were seen. Sedation was superior to that of acepromazine, xylazine or a combination of these. No serious side effects were seen.

Diagnostic value of contrast echocardiography in the horse.

M-mode echocardiography is a safe and practical means of using ultrasound to evaluate the dynamic movements of cardiac structures. The technique can be refined by using a simple contrast medium in the form of carbon dioxide mixed with heparinised blood to provide a strong echogenic result. This technique was employed in a series of 15 normal conscious standing horses and in three animals with specific cardiac defects. In the clinical cases it was possible to confirm the diagnosis and differentiate between a congenital septal defect and mitral regurgitation. The method was found to be safe and relatively simple to perform using percutaneous insertion of catheters. The intracardiac catheterisation was trouble free and no clinical side effects to direct injection of the carbon dioxide contrast medium into the heart were demonstrated.