My Dad complained of discomfort in his upper abdomen. He vomited twice in the morning before he left to his office. He was later admitted in the hospital later that night by his colleagues. The hospital did not seem to be a well equipped hospital (KS hospital, Kilpauk, Chennai). Doctors said he had a mild heart attack and he is stable. We decided to take him to MMM hospital since it was known for its Cardiology care. My dad's doctors refused and convinced him to stay in that hospital itself.
Since KS hospital did not have angiogram facility, he was shifted to Billroth hospital by the doctors. The next day morning, my dad suffered a massive heart attack and expired. Doctors in Billroth said that looking at the previous reports taken at KS hospital, the 1st attack was a massive 1 and not mild as said by the doctors in KS.
Could my dad have been saved if we had taken him to MMM hospital on the same day ? (We had only 3 days at hand and we were confused to take a decesion and it became too late to save him)

I am so sorry for your loss. It's very hard when you lose a loved one under such circumstances. You and your family are in my thoughts during this holiday season.

Now, to answer your question. There is no way to know whether he could have been saved if he were transferred to another hospital. This is a global site, so not many, if any, people will be familiar with the facilities you have named above.

He could have refused service at the first hospital and signed out AMA (Against Medical Advice), and went to the other hospital. But, again, that doesn't mean the outcome would have been any different.

I'm so sorry, I wish I had better news for you.