Last time, we reviewed the most common forms of stress testing that the FAA frequently uses to assess aeromedical risk in a setting of known or suspected coronary artery disease. However, there are other types of stress tests. The “pharmacologic nuclear stress test” is a type of exercise test in which one doesn’t exercise! The patient is administered a medication that causes the heart rate to increase in addition to being given a similar radioactive substance that I mentioned in the previous discussion. The patient is scanned at rest prior to administering the medication, then placed on the treadmill (if they are physically able, that is!) for about four minutes to enhance the effects of the medication, and are then re-scanned. The interpreter will compare the pre-medication pictures with the post, looking for the same things as in the exercise nuclear stress test.
The FAA, as a rule, does not like this test! Why? Well, for one thing, it is more expensive! But the main reason they don’t care for it is that you don’t physically exercise, and exercise stress is one of the physiologic touch points the FAA doctors use to assess medical fitness during the stress test. That is why they expect airmen to reach their maximum predicted heart rate. The exercise portion of the stress test places more work on the heart and thus, to the FAA cardiology consultants, makes that test a more accurate picture of how the heart responds to excessive workload. The test is indicated in certain types of heart block and in those cases, the FAA will actually request this study. They will also accept this test in lieu of the maximal nuclear stress test if the airman has a musculoskeletal problem and is unable to walk on a treadmill.
If this is so, you need to have your cardiologist put the explanation in writing on the test. For example, “Joe was administered a pharmacologic nuclear stress test as he has severe arthritis in his hips and cannot walk on a treadmill.” Note, if you have to have this type of test, you will more than likely have to have one each year depending on the special issuance you are given.
Last, let me explain what is called a “stress echocardiogram.” This is an exercise test where the airman initially has what is called an echocardiogram. This is a sonar test on the heart. It is a painless examination where a technician uses a machine that bounces sound waves off your heart and obtains live film of your heart beating. The cardiologist can tell many things about a person’s heart with this study, including the sizes of the heart and all its chambers, how well each chamber is functioning, whether each of the heart valves appears normal and is functioning normally, and most importantly in regards to exercise, whether the heart muscle contracts normally. This study also can identify ischemia or a scar in the muscle. After the resting echo is performed, the airman walks on the treadmill just as with all stress tests. After the patient exercises to the point of complete fatigue, the study concludes with the airman lying flat while a four-chamber view of the heart is done. The FAA doesn’t ask for this test from first or second class medical certificate applicants because of a lack of uniformity of the protocol for the test that varies among different institutions. The nuclear perfusion scan would be the more conventional study requested for a higher class of medical certification. However, I do feel that sometime in the near future the FAA cardiology consultants will begin permitting this test for all classes.
