EB-4 Visas are employment-based visas that are available to a limited selection of professionals. Only certain doctors and physicians are eligible, and they must meet strict criteria. If you are looking to move to the USA under one of these visas, it is very important that you fully understand the law.
What types of physicians qualify for this visa?
According to the United States Citizenship & Immigration Services, not every doctor is eligible for an EB-4 Visa. To qualify, a physician must:

Have graduated from a foreign medical school
Be licensed to practice medicine in a state
Be able to certify that they have met these criteria and provide all necessary paperwork

While you should consult with an attorney before applying for an EB-4 Visa, you must only meet the above criteria in order to qualify for this employment visa. As long as this is the case, there are no limits on the type of medicine you practice in order to qualify for an EB-4 Visa.
How can a physician obtain this visa?
If you want to apply for this visa, it’s important to follow the proper steps. Your employer has to file the appropriate paperwork and advocate on your behalf. You will also have to provide all appropriate paperwork and records to support your certification to practice medicine. In some circumstances, a physician can attempt to apply on their own behalf. You may want to ask an attorney if you would be eligible to submit an application without an employer.
As you can see, visa and immigration law can get complicated. Many migrants to the United States need legal assistance in ensuring that they are complying with the law and completing all paperwork correctly.