The possibility of recognizing a cardiac insufficiency by repeated thoracic roentgenograms at the bedside and the behaviour of the haematocrit value were investigated on 210 patients with infarction in the early phase. 56% of the patients with infarctions had roentgenological signs of a pulmonary stasis. Only half of these patients showed clinical signs of cardiac insufficiency. In 66% of the patients with infarctions increased haematocrit values were found, 19% of them had values of 60% and higher. Younger and male patients with infarctions had more frequently increased haematocrit values. In hypertension, diabetes, hyperlipidaemia, hyperuricaemia and adiposity patients with infarctions had increased haematocrit values in about 70% of the cases. The group of patients treated with as well as without diuretics showed 2/3 of the cases decreasing or remaining and in 1/3 of the cases increasing haemotocrit values.