[Practolol test for adrenergic beta receptor blockade in veterinary electrocardiographic diagnosis]

The receptor theory of the action of catecholamines as well as the synthesis and production of beta-adrenolytics gave new perspectives for the treatment of circulatory diseases and enabled to use the beta-adrenergic blockade in electrocardiographic diagnosis. The aim of this work was to study whether it is possible to modify the oral method of administration used in human beings, into intravenous one, and what an information could be obtained as to actual heart condition after practolol injection. The results can be summarized as follows:--Practolol-Polfa injected intravenously in amounts of 30-50 mg for horse or cow and 3-10 mg for dog in ten minutes deviates the curve evoked by sympathectomy;--after the administration of the drug functional changes of final ventricular complex disappear which is the result of adrenergic system prevalence;--repolarization disturbances observed after the blockade indicate a myocardial defect and later, a partial decrease of changes in T wave shows that a vegetative factor is involved;--increased disturbances of the repolarisation phase after the practolol test indicate of myocardial defect due to compensatory mechanism of adrenergic system in relation to serious hemodynamic disturbances of the heart;--practolol test gives wider possibilities of interpretation, not only from the diagnostic point of view, but therapeutic as well.