Cardio-toxicity of Daunomycin and Adriamycin.

Our aim was to check the possibility of modifying the cardio-toxicity of Daunomycin and Adriamycin on guinea pig atria in vitro, through a reduction of calcium concentration in the medium. In a first series of tests, left and right atria still beating were put in a bath containing Tyrode solution. In order to test the influence of hypocalcic conditions on the negative inotropic effects of the two drugs. Tyrode solution contained either the usual amount of calcium or only 50% of it. In a second series of experiments isolated tissues were electrically stimulated in Krebs-bicarbonate solution. In order to avoid the spontaneous activity of the preparations, only isolated left atria were used. Again the medium contained either the normal quantity of calcium or only 50%. The reduction of calcium concentration in the medium results in a statistically significant potentiation of the negative inotropic activity of the two drugs.