OBJECTIVES--To determine the effects of enoximone on mortality and quality of life in patients with severe end stage heart failure. DESIGN--A randomised, double blind, placebo controlled trial of the addition of enoximone to conventional treatment. Planned minimum follow up of one year. SETTING--District general hospitals and cardiological referral centres in the United Kingdom. PATIENTS--Planned 200 patients with severe, symptomatic heart failure despite treatment with diuretics and where appropriate and tolerated angiotensin converting enzyme inhibitors and digoxin. RESULTS--The study was ended early by the ethics committee after 151 patients had been recruited because of an excess mortality in the enoximone group: 27 deaths compared with 18 in the placebo group (P < 0.05). Quality of life measured with a disease specific questionnaire showed a clinically significant improvement at week 2 with a mean increase score of 0.48 in the enoximone treated patients compared with 0.14 in those receiving placebo (P = 0.0086). With the Nottingham health profile questionnaire the physical mobility score was improved after three months in the enoximone group, median 21.3 compared with 41.8 in the placebo group (P = 0.008). CONCLUSIONS--In patients with severe heart failure who remain incapacitated despite conventional treatment enoximone reduced survival but had a beneficial effect on the quality of life. Drugs that improve symptoms in severe end stage heart failure should not be discarded lightly.