Cardiovascular Effects of Chloroquine with Special Reference to Its Antifibrillatory Action

Intravenous injections of chloroquine terminated experimental atrial fibrillation in open chest dog preparations. Chloroquine and quinidine possess equal vasodilating properties when injected intra-arterially in the same dosage. Chloroquine and quinidine were equally effective in decreasing resting excitability of isolated cat papillary muscle; conduction velocity was markedly slowed by quinidine, but only slightly decreased by chloroquine.