Using polycardiography, right and left ventricular dynamics were studied in 22 healthy women in the 30th--40th week of physiological pregnancy and 75 patients with different forms of late toxaemia. It was found that late toxaemia is accompanied by deep changes in the phase structure of the right ventricular systole, corresponding to the elastic resistance load phase syndrome. Analogical changes in the left ventricular dynamics occur only in severe forms of the disease. The authors propose nomograms for determining the predicted length of ejection time, which can be used for diagnosing reduced myocardial contractility.