Sunday October 23, 2005
BY Dr NG SWEE CHOON
PREVENTION is better than cure. Medicine has entered the era of preventive medicine, where we hope to create greater awareness of health among individuals and teach them to know and appreciate good normal health, as opposed to sickness.
In a way, we are trying to work ourselves out of a job. If all illnesses can be prevented and the population at large follow all the preventive steps, then the need for doctors will be less. But alas, that will never be, although it remains our dream. Preventive medicine is also much more cost effective, and have lesser morbidity and mortality. It is our hope that this message gets through.
Myths to correct
What are we looking for when we go for a heart check? Well, we are obviously trying to see if the heart is in good condition. Whenever I get a request for a heart check, I sense that the client (we can’t call them patients as they have no illness) expects that after the heart check, he will be guaranteed that he is not going to suffer any cardiac events.
This is the first myth that we must correct. There is no one cardiac test (or even a series of tests) that can completely exclude a future or possible cardiac event. Heart checks merely establish the state of your heart at that point in time with the current available test. No test has a 100% predictive accuracy.
The second myth to correct is that one test can tell all. That is simply not true. There are so many aspects of heart disease and so many kinds of heart diseases that it is not possible for one test to tell all.
There is heart disease present from birth (congenital, for example, hole-in-the-heart), heart disease from valve defects (valvular heart disease), heart muscle disease (cardiomyopathy), heart artery disease (coronary artery disease), disease of the heart from hypertension and many others.
Besides these, there are tests for the functional aspects of the heart, tests for the structural defects of the heart, and tests for the electrical aspects of the heart. No one test can tell all. How can they?
The third myth is that all tests are free of risk. Generally, the more sophisticated the test, the more likely the possibility of side-effects.
What happens in a heart check?
Most often, we are trying to establish three things.
1. Is the heart structurally normal?
2. Is the heart functionally normal?
3. In those at risk of coronary artery disease (CAD), is there any evidence of heart artery blockage causing lack of blood supply?
The most important part of a heart check is the interview with the doctor. This must form the basis of all checkups. The present day factory-style “go through a barrage of tests” and then have someone interpret the results and prescribe health is medically incorrect. There is much that can be gained from having a doctor see you first and take a careful history and do a thorough physical examination, even if you feel well.
This simple check will allow the doctor to make an assessment and arrive at a provisional diagnosis, know what aspects of the heart check are important, what to look for and what tests to prescribe (that are relevant).
For example, we often see 30-something females without significant CAD risk factors going for a stress ECG. This subject has such a low possibility of CAD that the stress ECG cannot be interpreted.
We see respiratory function tests being done for subjects who cannot blow, stress ECG being done for hemiplegics who can hardly stand. Moreover, some “screening test” carries risks, which are not well highlighted to the subject. An example is radiation risk. Deaths have been known to occur with some “routine screening test”.
If you are a healthy adult, and going for a health check, any risk, no matter how small, from any test, be it radiation risk, medication risk from tablets taken before tests, physical injuries sustained while performing the test that you cannot perform is unacceptable. Even one is too many.
After the interview, as part of the check-up, the resting ECG and chest x-ray usually give us invaluable clues about the heart. It helps the doctor know what other test may be pertinent. These tests are simple and cheap, and give good information. The chest x-ray does have a small risk of radiation, (relevant to the pregnant female) but is virtually harmless otherwise. As you can see, some tests do carry risks, although small.
Blood tests are important too as they allow us to form a risk profile for the individual. Just as in insurance, where we risk profile clients, this also occurs in heart check-ups. The higher the risk profile, the more likely the presence of disease, and vice versa.
Blood tests for lipids and the exclusion of diabetes and renal disease helps us to risk profile the subject. We can also mark out a person’s risk for a heart attack by checking for certain high risk markers in the blood, like hs-CRP.