Diagnosing Heart Disease

Present-day technology provides many sophisticated procedures for establishing a precise and correct diagnosis in a heart patient. The process of arriving at a diagnosis involves three steps: (1) history taking and physical examination, usually supplemented by electrocardiographic and radiographic examinations, (2) complex noninvasive tests, and (3) invasive tests. In a great many cases, step 1 may establish a reasonable diagnosis. Step 2 greatly increases the cost of the diagnosis; echocardiographic and nuclear studies range from five to ten times the cost of the electrocardiogram and chest X ray. Step 3 not only raises costs still further but also introduces an element of risk—the possibility of the test causing physical complications or even death. It should be noted that noninvasive tests are performed by technicians: the physician sees and interprets only the results of the test. Echocardiography and nuclear tests thus require a great deal of expertise from the technical staff before the physician reviews the findings. Invasive tests are in essence surgical procedures performed by cardiologists with special training supported by an expert team of nurses and technicians.

Interpreting test results presents two types of difficulties. First, tests aimed at establishing the presence of a certain abnormality do

not always provide a definitive answer and may lead to a difference of opinion. Second, almost every test occasionally supplies incorrect information: certain changes expected to be present in a given disease may not be found (a false negative result), or the test may display changes suggesting a disease not present (a false positive result). In arriving at a diagnosis, the physician may encounter a maze of difficulties caused by uncertain, sometimes contradictory results of examinations and tests. Although establishing a correct diagnosis may represent a personal challenge to physicians, they should not lose sight of the goals of a detailed diagnosis: to determine the proper medical treatment for the patient and to evaluate the patient's prognosis. A diagnosis of heart disease can often involve much more testing than is necessary to fulfill these goals. Concerns about the cost of health care force us to consider the cost-benefit relationship that may lead to voluntary or imposed restrictions on performing tests, especially since cardiological procedures are among the most expensive in medicine.