Effect of epicardial application of amiodarone-releasing hydrogel on heart rate in an animal model

The purpose of the experiment was to study the safety of local epicardial use of the hydrogel with amiodarone, as well as the influence of its different dosages on the heart rate of mongrel rabbits.The epicardial application of the hydrogel material with amiodarone was performed in 46 rabbits. Rabbits were divided into 5 groups: Group No. 1-dose of amiodarone in the hydrogel 1 mg, Group No. 2-dose 3 mg; Group No. 3-dose 6 mg; Group No. 4-hydrogel without amiodarone; Group No. 5-amiodarone intravenously, 60 mg.The application of hydrogel with amiodarone is not accompanied by a systemic inflammatory reaction. In group No. 2, there was a significant reduction in the heart rate (before surgery: 158±16, after: 130±11, (P<0,001), without any disturbances to the conduction system of the heart functioning. With an increase in amiodarone concentration (Group No. 3), significant atrial and atrioventricular (AV) conduction defects (up to 70%) were noted; when the dosage of amiodarone (Group No. 1) was reduced, there was no influence on the heart rate reduction. The hydrogel without amiodarone has no effect on the conductive system.The method of local epicardial delivery of amiodarone in the form of a hydrogel material is safe. The hydrogel with amiodarone is effective for the heart rate reduction (according to the experiment on animals), compared to the control group and the group with intravenous drug administration. The optimal dosage of amiodarone in the hydrogel is 3 mg.