Comparison of cardiotropic drug effects on haemodynamic and myocardial energetics in patients with heart failure: a computer simulation

The purpose of our study is to compare haemodynamic responses and the ishae mic potential of commonly used inotropes (dopamine, dobutamine and milrinon e) using a computer model of the cardiovascular system. Cardiotropic drugs interact with the model by changing ventricular elastance and resistance of the individual circulation. All three drugs increase cardiac index in a do se-dependent manner Dopamine at medium and high infusion rates increases he art rate, systemic vascular resistance and arterial blood pressure. The ass ociated increase in coronary blood flow, however, is not sufficient to acco unt for increased oxygen, demand. Both dobutamine and milrinone decrease va scular resistance and increase coronary blood flow. The more pronounced inc rease in heart rate associated with dobutamine, however, results in a highe r ischaemic potential for this drug. Our simulation demonstrates that altho ugh all the drugs studied improve cardiac function in simulated patients wi th heart failure, milrinone accomplishes this at a lower energy cost. The c omputer simulation developed can be used to assess the complex effect of ca rdiotropic drugs and possibly suggest optimal drug therapy in specific clin ical situations.