Abstract A number of 5, 7-dialkyl-s-triazolo [1, 5-a] pyrimidines and 5, 7-dialkylpyrazolo [1, 5- a] pyrimidines and related heterocycles containing a bridgehead nitrogen have been prepared and studied as cardiovascular agents in the anesthetized dog. A number of these compounds have exhibited significant inotropic activity with little effect on heart rate. Especially active were 5, 7-dialkyl-2-amino or 2-alkylthio-s-triazolo [1, 5-a] pyrimidines. In ...