Probing the power of prayer CNN Headline News A recent, controversial study of cardiac patients conducted at St. Luke's Hospital in Kansas City, Missouri, concludes that this type of prayer -- known as intercessory prayer -- may indeed make a difference. "Prayer may be an effective adjunct to standard medical care," says cardiac researcher William Harris, Ph.D., who headed the St. Luke's study. The study was published in the October 25, issue of the Archives of Internal Medicine. Harris and team examined the health outcomes of nearly 1,000 newly admitted heart patients at St. Luke's. The patients, who all had serious cardiac conditions, were randomly assigned to two groups. Half received daily prayer for four weeks from five volunteers who believed in God and in the healing power of prayer. The other half received no prayer in conjunction with the study. The volunteers were all Christians. The participants were not told they were in a study. The people praying were given only the first names of their patients and never visited the hospital. They were instructed to pray for the patients daily "for a speedy recovery with no complications."