The trial also included a registry which enrolled 6,300 patients to study the influence of a number of patient characteristics on mortality. Eighteen of the clinical centers participated. Data were collected from consecutive patients with ejection fraction less than .45 or with radiologic evidence of congestive heart failure over a twelve month period. At one year, patient's vital status was ascertained by mail and, if necessary, by telephone follow-up. One year follow-up was completed on all registry patients by May 1990. Longer term follow-up was done through the National Death Index.