Caritas Christi Health Care, the ailing hospital chain owned by the Archdiocese of Boston, is expected to hire Ralph de la Torre as chief executive. De la Torre is the chief of cardiac surgery at Beth Israel Deaconess Medical Center, and has built Beth Israel's Cardiovascular Institute into a thriving business within the hospital. De la Torre said he is interested in developing cardiac care at the Caritas Christi system, as well as possible relationships with Beth Israel Deaconess.