Title:Kamrai tachycardia sikeres gyógykezelése szájon át adott propranolollal három ló esetében
SUMMARY Background: Cardiac arrhythmias are relatively common in horses, but ven-tricular tachycardia is infrequent, therefore limited information is available about its therapy in the Hungarian literature.Objectives: To present three cases of ventricular tachycardia treated success-fully with orally administered propranolol.Materials and methods: Descriptive clinical report.Results and discussion: Three horses with elevated heart rate and colic like signs were referred to our equine clinics for further investigation and therapy. After excluding gastrointestinal and systemic diseases, uniform ventricular tachycardia was confirmed by resting electrocardiography using base-apex lead. Other ancillary diagnostic tests including echocardiography, measurement of serum cardiac troponin I concentration were used to reveal signs of structural cardiac abnormalities and possible myocardial injuries. Cardioversion in all cases was started with lidocaine first administered in bolus, then as a continuous rate of infusion. This treatment did slow the rate temporarily but was unable to con-vert the rhythm. As soon as the continuous rate infusion was withdrawn, a quick and spontaneous return to a marked tachycardia occurred. Therefore, following human literature and reported dose rates in horses, propranolol was adminis-tered orally. This therapy subsequently led to conversion to sinus rhythm. All horses received crystalloid fluids intravenously and other supportive treatment. Intravenous dexamethasone sodium phosphate was also given to two animals. After the conversion and successful recovery, horses were discharged, and the oral propranolol therapy was continued at home for different duration between eight days and one month. Follow-up cardiac examination four to eight weeks later revealed sinus rhythm in all cases. Our findings highlight the importance of performing ECG on horses with resting tachycardia exceeding 70-80/beats per minute.