For decades, Mercy Medical Center-Sioux City has been the area’s leading hospital for the diagnosis and treatment of cardiovascular diseases. The Mercy Heart Center brings together experienced cardiologists and surgeons, highly trained staff and the latest technology in a modern, full-service facility. For diagnostic and interventional procedures, open-heart surgery, or for advanced medical procedures like electrophysiology, trust your heart to Mercy, the hospital that ranks among the best medical centers in the nation for cardiac care.