Cardiology is a medical specialty with two branches: non-invasive cardiology and interventional cardiology. Although the training, licensing and certification requirements for both types of cardiologists are similar, the salaries are quite different. Interventional cardiologists earn considerably more than their counterparts, especially in some geographic areas. Some cardiologists in the New York City area, for example, earned over $3 million a year, according to an October 2010 article on the website for "CardioBrief."

Divergent Specialties

Cardiologists begin as internal medicine specialists. They follow the typical course of college, medical school and residency, which takes about 11 or 12 years. The internist must pass the certification exams in internal medicine before beginning a period of special training -- called a fellowship -- in cardiology. The fellowship is where cardiology and interventional cardiology begin to diverge. Although interventional cardiologists are not surgeons, they do perform invasive procedures. Interventional cardiologists learn to perform procedures such as cardiac catheterizations, insert small metal or plastic tubes called stents, insert filters in blood vessels or even repair heart valves with small catheters and special tools.

Salary Ranges

Cardiologists in general had a median starting annual salary of $272,000 in 2011, according to the Profiles database, a national physician salary resource. After six years in practice, Profiles reports cardiologists could expect to earn $402,000. Merritt Hawkins, a nationwide physician recruiting firm, reports that in 2011 interventional cardiologists were offered salaries ranging from $380,000 to $650,000, with an average of $532,000. The American Medical Group Association reported an average annual salary of $524,731 in 2012 for cardiologists who worked in a cath lab.

Regional Differences

Interventional cardiologists perform procedures that bring in revenue for hospitals, as insurance companies like Medicare and Medicaid pay more for invasive procedures such as a cardiac catheterization. Regional differences can affect physician salaries, according to a February 2010 article in "Forbes" magazine. Choosing to practice in the Midwest and South might increase a doctor’s salary by $10,000 to $60,000 a year. Rural areas may have difficulty enticing a cardiologist and may offer an increased salary or sign-on bonus as an inducement, according to "Forbes." Hospitals in big cities on the coast, however, may not need such inducements, as many physicians prefer to live in those locations.

Top Salaries and Bonuses

In some hospitals or locations, interventional cardiologists may earn a great deal. Mount Sinai and New York-Presbyterian hospitals paid their top interventional cardiologists at least $3 million per year in 2010, according to “CardioBrief.” Large medical centers and teaching institutions that perform research are more likely to offer large salaries because they perform a high volume of procedures. Cardiologists at Ohio State University who specialize in electrophysiology -- a sub-specialty of interventional cardiology -- earned $1 million dollar bonuses in addition to their salaries in 2011, according to an April 2012 article in “Forbes.”