Fendilin hydrochloride was tested in 9 normal anesthetized dogs and in 7 anesthetized dogs with acute coronary artery occlusion. The compound (1 mg/kg i.v.) caused a slight short lasting increase in coronary blood flow together with an increase in cardiac metabolic rate for oxygen of similar magnitude. There was no measurable effect on collateral conductance. No noteworthy effects on systemic hemodynamics were observed.