[Search for and study of antiarrhythmic substances among crown ethers]

The authors studied antiarrhythmic properties of macrocyclic polyesters. Some of the esters exhibited antiarrhythmic activity coupled with low toxicity. It was found that antiarrhythmic action of these substances is not mediated via acetylcholine and/or catecholamine system responsible for nervous regulation of the cardiac activity. The compounds under study were found to have marked antifibrillar properties. Experiments on an isolated rat heart demonstrated calcium specificity of the antifibrillar action of cyclolactones. It is assumed that macrocyclic polyesters represent a new class of antiarrhythmic agents having a direct cardiotropic action.