A quick thing about Interventional Cards (IC) vs. VS. There are a couple of big differences that separate the two. First, training, IC is 3 years of IM residency, 3 years cards fellowship, 1 year interventional fellowship. VS is either 5 years of residency or 5 years gen surg + 2 years fellowship. Roughly equivalent. The difference is really medicine vs. surgery. To be blunt, I could not survive an IM residency. For ME they are just too slow. Too much fixation on small details, too much endless rounding.
I am on interventional cards right now as an IVS resident (we do about 4 months of IC). We start rounding at 10am (I get to the hospital about 7am) and round until 3pm on a good day and 7pm on a bad day. Mixed in are maybe 3-4 cardiac caths. By definition the cases IC do are the same. The vast majority only do heart caths. They are extremely good at them, but the territory while exceptionally important is limited. They are a procedural medical specialty. But MEDICAL. It is more a mindset than anything.
This is contrast to a VS service. I was on one of ours for 2 months in July/August. We start to round at 6am, (I arrive at hospital at 5am) so that we can start operating at 7:30am. Operate until cases are done ~3-6pm. Take care of things on the floor in between cases or after things are done. I would say on average we see twice as many patients as a typical medical team will in about half the time. The medical care is good, but there isn't a focus on preventative care, medical optimization, and tracking down unrelated issues, so things simply go faster. That is what I like, but it is NOT for everyone. It is a harder schedule, but it is much faster paced and if you enjoy it, it will go a heck of a lot faster than a shorter day of medical rounds.