Hey,
I think your question is incomplete, kindly complete it so we can help you accordingly.
As you write diploma in cardiothoracic nursing, so this is a field in medical branch from where you can land in good job opportunity like nurse at operation theatre, cardiac surgery wards, etc.
And if you want to know about college then there are some best college for that :-

• AIIMS
• Jawaharlal Institute of postgraduate medical education
• AFMC, PUNE
• college of nursing CMC
• Guru govind singh indraprastha university

For more information go through these links:-
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/courses/cardio-thoracic-nursing-course%23:~:text%3DThe%2520cardio%2520thoracic%2520nursing%2520course,post%2520and%2520before%2520the%2520operations.&ved=2ahUKEwjlmOihz87wAhUwyDgGHepmDioQFjABegQIBBAF&usg=AOvVaw3O6TkYTl-MMujglCQ3yolw&cshid=1621182643521

https://www.google.com/url?sa=t&source=web&rct=j&url=https://medicine.careers360.com/colleges/list-of-diploma-in-cardio-thoracic-nursing-colleges-in-india&ved=2ahUKEwjlmOihz87wAhUwyDgGHepmDioQFjACegQIGBAC&usg=AOvVaw3k4kpai1o5hdMdVaO78bjQ&cshid=1621182643521

Hi Aspirant,

It is a course for post BSc.The eligiblity criteria says that Candidates who have passed PC B.Sc (Nursing)/B.Sc (Nursing)/ GNM with one year experience as a Staff Nurse are eligible to apply.The duration for this course is 1 year.The course level is of PG Diploma.

Hope it helps!!