Making the Diagnosis
An electrocardiogram (ECG) detects abnormal electrical cardiac charges.
In someone who has had heart damage, the electrical signals that keep the heart
beating change as they pass through damaged tissue. This can be detected and
measured.
Stress tests indicate how much oxygen the heart is getting during periods
of activity, and can also show if the coronary arteries are too narrow. An exercise
tolerance test is performed on a treadmill or a stationary bicycle while hooked
up to an ECG. A thallium scan allows imaging of blood flow in the heart
during exercise. This involves injecting a very small dose of radioactive substance
into the bloodstream, which is followed through the heart by a special camera.
With angina, abnormalities in the ECG may only occur while the person is
having an angina attack. Some people have "silent angina," where
even an attack brings no symptoms. To detect this, you may be asked to wear
a monitor for 24 hours. The ECG tape is analyzed for irregularities, and then
compared with a detailed diary, in which you record your daily activities and
any unusual symptoms.
Coronary angiography (or arteriography) is a test used to explore
the coronary arteries. A fine tube (catheter) is put into an artery of
an arm or leg and passed through the tube into the arteries of the heart. The
heart and blood vessels are injected with contrast which is then filmed with
an X-ray while the heart pumps. The picture that is seen, called an angiogram
or arteriogram, will show problems such as a narrowing or blockage
caused by atherosclerosis.