Haemodynamic effects of inosine were studied in intact dogs and subsequently in patients suffering from prolonged otherwise intractable cardiogenic shock. The nucleoside significantly improve myocardial performance in patients with an extremely low cardiac index by 63 +/- 29% as well as animals with no signs of haemodynamic deterioration, increasing cardiac output by 12.2 +/- 4.3%. These results suggest that inosine may become a promising inotropic agent. Further studies though are necessary to elucidate the mechanism of inosine action.