Changes of cardiac biopotentials in dogs subjected to various [anaesthetic agents] | Dažādu anestēzijas līdzekļu ietekme uz sirds biopotenciālu izmaiņām suņiem

The research was performed on 34 healthy German Shepherd and 32 Cocker Spaniel practically healthy dogs. SHILLER’s electrocardiograph AT – 1 Veterinary produced in Germany which allows a simultaneous work with 10 electrocardiograph leads. The premedication was achieved by means of 0.054 % atropine sulphate solution (0.02 mg kgE-1) in combination with 1% acepromazine maleate solution (0.06 mg kgE-1) intramuscular injection and general anaesthesia (narcosis) was achieved by means of 5% ketamine hydrochloride solution (6 mg kgE-1) in combination with 0.5% diazepam solution (0.6 mg kgE-1) intravenous injection. The following parameters of ECG have been analyzed: P wave, Q, R and S waves of QRS complex, as well as PQ, QRS and QT intervals. It was establish that: 1. According to the records done in ECG standard lead II, P wave in dogs subjected to premedication and general anaesthesia developed very much in line according to the breed of the animal. Premedication agents altogether did not change P wave much, whereas the total effect of anaesthesia agents manifested as statistically true increase of P wave amplitude – apparent already in the first minute of general anaesthesia of Cocker Spaniels, and only in the 60th minute of general anaesthesia of German Shepherd dogs; 2. According to the records done in ECG standard lead II, the depth of Q wave and height of R wave in dogs subjected to premedication and general anaesthesia remained almost stable. The Q wave of Cocker Spaniels was altogether much deeper (P is less than 0.05) and the R wave - much higher compared to German Shepherd dogs (P is less than 0.001); 3. The depth of S wave recorded in dogs in ECG standard lead II increased only slightly during premedication. The effect of general anaesthesia on Cocker Spaniels manifested both of increase and decrease of the absolute value of S wave (P is less than 0.05), which remained relatively stable in German Shepherd dogs. S wave recorded in ECG standard lead II was always deeper in Cocker Spaniels compared to German Shepherd dogs; 4. Premedication agents significantly increased ECG-PQ interval in German Shepherd dogs (P is less than 0.01), and had little effect on ECG-PQ interval in Cocker Spaniels. This pattern conformed to the changes of heart rate recorded in dogs of both breeds during premedication. The total effect of general anaesthesia ketamine hydrochloride and diazepam (after the effect of premedication appeared) manifested in dogs as shortening of PQ interval, however the pattern of shortening was different for each of the breeds; 5. Premedication atropine sulphate and acepromazine maleate significantly increased QT interval recorded in ECG standard lead II (P is less than 0.05) in animals of both breeds. The total effect of general anaesthesia (after the effect of premedication appeared) altogether manifested as shortening of QT interval: during the first minute of general anaesthesia changes were equally fast in animals of both breeds, however during the next 15-30 minutes this process developed according to different pattern depending on the breed of the animal.