Coronary Artery Disease Diagnosing

The three symptoms most commonly reported during emergency room visits are stomach aches, fever, and chest pain. Chest pain is potentially the most serious symptom, as it may indicate coronary artery disease or a heart attack. A range of diagnostic tools such as electrocardiograms, ultrasound, and angiography are used to determine the presence of CAD.

Electrocardiogram: The EKG or ECG

Normal EKG Reading - HealthTree.comAn EKG/ECG, or electrocardiogram, is one of the best-known diagnostic tools for the heart. During an EKG, electrodes are attached to the skin on the chest. These electrodes measure the heart’s electrical impulses. An electrocardiogram provides a record of the heart’s activities. The presence of ischemia and heartbeat irregularities can be detected with an electrocardiogram. An EKG can also detect evidence of a heart attack.

Echocardiography, Ultrasound, and the Ejection Fraction

Echocardiography is a specialized ultrasound used to evaluate the function of the heart. During an echocardiography, high frequency sound waves are used to construct an image of the heart on an ultrasound monitor. Analysis of the echocardiogram can be used to approximate the heart’s ejection fraction. The ejection fraction estimates how much blood is pumped out of the heart during a heartbeat. Abnormalities in the ejection fraction and blood flow can be used to determine the presence of heart failure or other heart conditions.


While an EKG or echocardiogram can provide information about heartbeat, ejection fraction, blood flow, and other heart conditions, the definitive diagnostic tool for CAD and heart attack is angiography. During angiography, dye is injected into the bloodstream. As the dye travels through the arteries supplying the heart, x-ray images are obtained so that the blood flow can be visualized.

Angiography allows doctors to estimate blood flow through coronary arteries. Narrow or blocked arteries can be easily identified. These results are often used to determine the need for surgery or other treatments.

Cardiac Enzymes and Chest Pain

Certain cardiac enzymes appear in the blood after a heart attack. A blood test may reveal increased levels of lactate dehydrogenase, CK-MB, troponin, and other cardiac enzymes. These enzyme levels will aid in the diagnosis of a heart attack.

X-Ray and Plaque Formation

When chest pains are reported, a simple x-ray may detect indications of CAD. An enlarged heart, a common sign of heart failure, may appear on an x-ray. Further, atherosclerotic plaques may show up on x-rays as areas of calcification.

Exercise Stress Test

An exercise stress test uses a treadmill or stationary bicycle to measure the effects of physical stress on the heart. Stress tests are usually performed in conjunction with an electrocardiogram to record the heart’s reaction to stress.

Changes in heart function may appear on the EKG during the stress test. Abnormal stress test results indicate the need for further testing by angiography or echocardiography. Chest pain during a stress test should be reported immediately.

Thallium Stress Test

A thallium stress test is a specialized type of exercise test. In this test, thallium, a mildly radioactive compound, is injected into the blood and taken up by the heart muscle. Results of a thallium stress test provide in-depth information about the location of heart tissue damage, blood flow problems, and the heart’s metabolism. Thallium stress tests are often used to determine if heart surgery is required.