Hello there! 

Greetings! 

To become a Cardiologist , after completing mbbs , you need to go through :-

1. Get the admission in PG course leading to Doctor of Medicine (MD) in general medicine.
2. After finishing three-year degree of MD, go for the super specialty course of 3-year DM in Cardiology to be a Cardiologist.

Thankyou 

Though neet ug you get into a medical college for MBBS and after you pass it you are only a general physician , then you have to do PG , for cardiology you have to do MD in medicine and then after MD medicine finally DM for cardiology
All the very best
I hope it helps