Oh, and that's a take off from Ed34's question on multi-use pills.
I imagine they're trained to know which medications work best for which heart problems. As for dosage, I'm not sure. If you look at a PDR the book mentions standard dosages for children, adults and geriatric folks.
I know with the antibiotics I use at work we choose which antibiotic works best for which type of injury or specific bacteria. I always calculate dosage according to species (mammals have a different calculation compared to birds or reptiles) and weight. Weight is very important. It doesn't seem to be so sensitive when it comes to humans.
Back to heart meds, what works for one person with PSVT may not work for another. Thank goodness the docs have more than one choice to try.
A beta blocker like Coreg or Antenolol is usually started with a very small dose as the effects can be huge when starting out. For example, I was given 3.175mg Coreg X 2 daily, and the effects were strong. After a couple weeks, my body got used to it so that was doubled, and doubled again until I was taking 50 mg daily. That proved to be too much so my dose is now 25 mg daily. The same procedure is usually followed with ACE and Calcium blockers. Frequent blood tests are important of course, as are EF tests when applicaable.
Ed's post is really interesting, this could be a study with huge ramifications.
I can only answer for the cardiologists I have had. They tend to stick to the same brand for each medication and gain a kind of experience in what dosage to administer. My cardiologists tend to stick to bisoprolol, ramipril, atorvastatin for example. I suppose over the years you get a kind of feel for how much a patient would need.