You cannot study MD after B.Sc. You can only study M.Sc or relevant courses. MD is after MBBS/BDS etc. If you want to study further, you can  pursue your Masters in:

1. Anatomy
2. Physiology
3. Biochemistry
4. Pathology
5. Microbiology
6. Cardiac care technology

If you want to start working right away your target Employment areas should be:

1. Educational Institutions
2. Health care departments
3. Hospitals and Clinics
4. Nursing care homes
5. Rehabilitation centers
6. NGOs

Few roles that you can apply for are:

• Cardiovascular technologist
• Echocardiographer
• Medical Sonographer
• Cardiovascular technician
• Registered vascular specialist
• Cath lab technician
• ICU Intensivist
• Cardiologist
• Dialysis Technician
• Nephrologist

Dear Aspirant

yes, you can do MD after B.Sc Cardiology. Apart from opting MD you can also able to pursue higher education in degrees such as M.Sc, MBA and other PG medical and Diploma courses.

Hope it helps! Good luck!