I'm a Ph.D. in Clinical Psychology in Italy. Now I'm begining a research project on psyhological risks factors for cardiac disease (in Italy). How I can have a Ph.D.in Health Psychology using this research project? How I can found a supervisor interested?

You need to find a supervisor who is working in a similar area of research who will take you on as their student. A literature search should help you do this. Write to the person concerned, explain your current position and ask if they would be willing to take you on.