WITH THE development of low-priming volume oxygenators, assisted circulation has become available for emergency use. It has been suggested as treatment for a number of conditions including septicemic shock, 1 cardiac arrest, 2,3 pulmonary insufficiency, 4 and congestive heart failure. 5-12 Of these, emphasis has been placed on the use of circulatory support for the treatment of intractable heart failure after a myocardial infarction. The results, however, have been inconsistent and further evaluation of the use of assisted circulation in the treatment of heart failure is indicated. In a previous publication, 13 a technique was described for the production of experimental heart failure in animals by multiple coronary ligations. The resulting failure was found to be comparable to that occurring clinically following a myocardial infarction. The purpose of this study is to evaluate the effectiveness of various methods of assisted circulation in the treatment of experimental heart failure. Methods Heart