Nazim Shikhverdiyev - cardiac surgeon, professor, doctor of medical sciences, honored doctor of the Russian Federation, laureate of the State Prize of the Russian Federation. In his new book "Heart Duty. Heart surgeon about the cost of mistakes" the author shares professional and life experience, interesting and tragic cases from medical practice, personal stories of patients. Medical errors are not only a matter of the medical community, but also a big social problem that can affect every patient. Unfortunately, in our country there are no clear legal criteria to determine what is considered a medical error. And this problem must be solved." Long Heart" is a book-reflection on the degree of responsibility of a doctor for other people's lives, about a real vocation and a difficult ethical choice.