Given the following passage "Hyderabad is also home to a number of centres specialising in particular fields such as biomedical sciences, biotechnology and pharmaceuticals, such as the National Institute of Pharmaceutical Education and Research (NIPER) and National Institute of Nutrition (NIN). Hyderabad has five major medical schoolsOsmania Medical College, Gandhi Medical College, Nizam's Institute of Medical Sciences, Deccan College of Medical Sciences and Shadan Institute of Medical Sciencesand many affiliated teaching hospitals. The Government Nizamia Tibbi College is a college of Unani medicine. Hyderabad is also the headquarters of the Indian Heart Association, a non-profit foundation for cardiovascular education.", answer the following question. Note that the answer is present within the text. Question: This city has the headquarters of a non-profit investigating what system?
A:
cardiovascular