The study of methods for minimizing the mass of ischemic infarcted myocardium associated with a myocardial infarction was identified as a topic of research priority in the 1973 Report of the Panel Chairman for the Preparation of the National Heart, Blood Vessel, Lung, and Blood Program. In September 1976, the Institute convened a workshop involving 32 investigators active in this field, respondents to past solicitations, experts on the topic of collaborative clinical trials, members of previous review committees, and several members of the Cardiology Advisory Committee. The attendees were enthusiastic about the practicality and timeliness of a collaborative clinical trial in this field. The concept of collaborative clinical trials to protect ischemic myocardium was discussed by the Cardiology Advisory Committee in its meeting of September 22, 1976, and was recommended affirmatively and enthusiastically. This trial was part of the Institute's initiatives and was reviewed and favorably recommended by the National Heart, Lung, and Blood Advisory Council at its December 1976 meeting. The trial consisted of five clinical centers, six central laboratories, a clinical coordinating center, and a data coordinating center.