Your question seems like a homework assignment.
http://www.theheart.org/article/131813.do
I'll ignore the trolling on this thread and try to follow CaliGirl's attempt to get this thread back on track, since there are legit issues here.
Per the article, for those who don't want to read, the factors suggested that have dissuaded folks from going into the field are the very challenging professional lifestyle demands of cardiothoracic surgery, the declining rewards for the profession because of both decreased reimbursement and increasing medical liability exposure, and the fact that 50% of medical students in the US today are women, who show relatively little interest in the surgical specialties for quality of life/family reasons.
Truth of the matter is that when the income fell away, folks going into surgery found plenty of other surgical paths which allowed for much shorter residency/fellowship paths, greater income, better lifestyles. At the same time, as mentioned, a lot of the procedures that used to require a cardiothoracic surgeon to open your chest back in the day now can be done by cardiologists via EP, or by IR, with equivalent success rates. At the same time, medicine has came up with much better heart disease meds (eg statins) that reduced the patient population as well.
When I was in med school, we used to have lecturers come and tell us that cardiothoracic was literally a dying field, with the average age of cardiothoracic surgeons now in their late 60s and getting older every year (not sure if the trend changed since then).
That being said, you need to choose what you like to do, because, especially in the surgical fields, it is going to consume all of your awake time. If you love it, that's great. If not, pick something else. The money in medicine will be adequate whatever you choose, but it won't make something non-interesting to you interesting.
