Tissue Concentrations of Digoxin in an Autopsy Material

: The tissue concentrations of digoxin were measured in 13 cadavers who before death had been on the maintenance digoxin therapy. Tissue samples were taken from 5 different parts of the heart, from skeletal muscle, liver and kidney. Digoxin was extracted by dichlormethane and measured by radioimmunoassay. Whole blood digoxin was measured by the same method. The appropriate recovery studies showed good extraction. The highest heart digoxin concentration was found in the septal muscle (mean 132 ± S. D. 65 ng/g) and the lowest in the left auricle (43 ± 26 ng/g). The heart concentrations were in good correlation with the whole blood concentration — the best correlation was found with the ventricular muscle (r = 0.86). The skeletal muscle concentration was about 15 % of the heart concentration (20 ± 13 ng/g) and the correlation with the whole blood was poorer (r = 0.54). The kidney concentration (123 ± 65 ng/g) was approximately the same as that of the heart and the liver concentration was 68 ± 51 ng/g. The results indicate a linear correlation between blood and heart.