Testing can sometimes serve no useful purpose
Frequently, I see asymptomatic patients who report a “clean bill of health” from their cardiologists. Their electrocardiogram, stress test, echocardiogram and CT scan of the heart are normal.
Occasionally, these patients are being screened because they have a known coronary artery disease. But quite frequently, they are middle aged or older and are being screened to ensure no problem exists. With these patients, the tests have no value and the cost is high.
So what are these tests and when should they be done? An electrocardiogram, or EKG, measures the electrical activity of the heart. With each heartbeat, an electrical current begins in the top of the heart and moves down a conduction system, stimulating the heart to contract. Electrodes placed on the chest and arm read out this electrical activity. The pattern of the readout can detect a new heart attack, evidence of an old one and irregularities of the heartbeat.
It is an invaluable diagnostic tool for someone who has symptoms suggestive of a heart attack or to diagnose conditions such as atrial fibrillation in which gross irregularities of the heart rate can lead to an increased risk of strokes and heart failure. However, as a screening test, an EKG has virtually no value. It may miss heart problems and just as frequently, may show changes suggesting heart disease that is not present.
A stress test involves stimulating the heart to beat faster either by exercise using a treadmill or by mimicking the effect of exercise with the injection of a medication (persantine) and a radioactive marker that can identify areas of inadequate blood supply. This test remains a “gold standard” to diagnose coronary artery disease in someone with chest pain or shortness of breath. However, no study has shown the test to be of value as a screen for coronary artery disease in a healthy, asymptomatic person.
An echocardiogram is a test that allows a complete evaluation of the four chambers of the heart and the way in which the heart contracts with each heartbeat. It measures the amount of blood that is pumped out of the heart with each beat and can evaluate the function of the heart valves between the chambers of the heart and pulmonary and aortic arteries. This noninvasive procedure can identify severe weakness or dysfunction in the way the heart muscle contracts, as well as diagnose problems with the heart valves. This test never should be used as a screening test in normal individuals.
Of all the screening tests, the cardiac CT scan is the most problematic. Used as a marketing tool, this test promises unwary consumers the potential of saving lives by performing this “heart saving” CT scan. Coronary artery disease is suspected if increased calcium in the arteries is noted. Combining a CT scan with the injection of a dye can demonstrate significant blockages of coronary arteries.
In chronically or severely ill individuals, a cardiologist may prefer a less invasive CT scan to an angiogram to diagnose coronary artery disease. The scan provides a great deal of irradiation and is of no proven value as a screening test. Particularly egregious is the use of a CT scan to screen for heart disease in anyone older than 70. At this age and beyond, the narrowing of the coronary arteries is very common.
By identifying excessive calcium, additional evaluations, including angiograms, angioplasty and even open-heart surgery, may be done. The patient may believe a heart attack will be prevented and life prolonged. Unfortunately, invasive procedures do neither — they relieve symptoms, which these patients do not have.
Prevention is the key to managing heart disease. It is all about diet, exercise, stress reduction and control of blood pressure and cholesterol.
As for me, 16 years ago I had a heart attack. Since then, I haven’t had an EKG, stress test or echocardiogram. Even with known heart disease, these tests are only needed if new symptoms, such as chest pain, palpitations or shortness of breath, occur.
Understand that unnecessary screening tests do more harm than good, and their cost is contributing to the collapse of our health care system.