Thirteen patients with chronic congestive cardiac failure and refractory oedema were treated by haemodialysis. All patients had severe cardiac failure (Class IV NYHA) due to primary myocardial disease (5 cases), ischaemic heart disease (4 cases) or valvular heart disease (4 cases). Haemodialysis was performed via a Shaldon Y-shaped catheter in the internal jugular vein, with input and output through the same catheter using an alternating clamp. Filtration was carried out through a highly permeable membrane by a simple hydrostatic pressure gradient without a dialysis bath. The sessions were monitored haemodynamically by measuring the pulmonary artery pressures. The mean weight loss was 4.9 +/- 0.4 kg obtained after 3 three hour dialysis sessions with 24 hour intervals between each session (mean filtration flow = 12 ml/min). Hypotension was observed in one patient with low initial pulmonary artery pressures; two patients with severe valvular stenosis (1 mitral stenosis; 1 aortic stenosis) failed to lose weight. In the 10 remaining cases, there was a clearcut symptomatic improvement (5 patients Class III; 5 patients Class II NYHA) with total regression of oedema. There was a significant fall in pulmonary artery (mean PAP 40.5 +/- 6.5 mmHg to 34.6 +/- 6.5 mmHg; p less than 0.001) and pulmonary capillary pressure (27.6 +/- 6.9 mmHg to 22.5 +/- 5.8 mmHg; p less than 0.05) in these 10 cases. Cardiac output did not change significantly (cardiac index 2.2 +/- 0.5 l/m2/min compared to 2.3 +/- 0.4 l/m2/min after dialysis).(ABSTRACT TRUNCATED AT 250 WORDS)