In order to study the effects of soman intoxication on hemodynamics,the left ventricular pressure(LVP),the maximal changing rate of LVP(?dp/dt max),the aortic pressure(AP),the pulmonary arterial pressure(PAP),the cardiac output(CO),the cardiac index(CD and the heart rate(HR)were determined in anesthetized,chest -opened and mechanically-ventilated dogs at a simulated high altitude of 4 000m before and after an intravenous injection of 10?g/kg of soman.It was found that the toxicity of soman on cardiac functions was more severe at high altitude than at sea level.