CABG See Coronary Artery Bypass Surgery Diagnosis 

Diagnosis 

Doctors diagnose angina largely based on  a person's description of  the symptoms. A physical examination and ECG (see Symptoms and Diagnosis  of Heart and Blood Vessel Disorders: Electrocardiography) may detect little, if anything, abnormal between and sometimes even during attacks of angina, even in people with extensive  coronary artery disease. During an attack, the heart rate may increase slightly,  blood pressure may go up,  and with a stethoscope, doctors may hear a change in the heartbeat. ECG may detect changes in the heart's electrical activity. 

When symptoms are typical,  the diagnosis is usually easy for doctors. The kind  of pain, its location, and its association with exertion, meals, weather, and other factors help doctors make the diagnosis. The presence of risk factors for  coronary artery disease also helps establish the diagnosis. If a person experiences chest pain during the examination, a doctor may place a dose of nitroglycerin Some Trade Names 

NITROLINGUAL 

(a drug that dilates  blood vessels) under the person's tongue as a test, because if the pain is due  to angina, relief should occur in less than 3 minutes. 

The following procedures may help evaluate the inadequate blood supply (ischemia) to the  heart muscle and determine whether coronary artery disease is present and how extensive it is. 

For exercise stress testing (see Symptoms and Diagnosis of Heart and Blood Vessel Disorders: Exercise Stress Testing), the person walks on a treadmill or rides a stationary bicycle while being monitored by ECG. This procedure  can help doctors determine whether coronary angiography  or coronary artery bypass grafting (CABG) is needed. If people cannot exercise, testing is done after a drug that makes the heart work harder is injected (a procedure called pharmacologic stress testing). 

For radionuclide imaging (see Symptoms  and Diagnosis of Heart and Blood Vessel Disorders: Radionuclide Imaging), a tiny amount of a radioactive substance is injected into a vein. Radionuclide imaging can identify the location and extent of ischemia and show the amount of blood reaching the  heart muscle. This procedure is usually combined with stress testing. 

Echocardiography (see Symptoms and Diagnosis  of Heart and Blood Vessel Disorders: Echocardiography and Other Ultrasound Procedures) uses ultrasound waves to produce images of  the heart (echocardiograms). This procedure shows heart size, movement of  the heart muscle, blood flow through the heart valves, and valve function. Echocardiography is done during rest and exercise. When ischemia is present, the pumping motion of the left ventricle is abnormal. 

For  coronary angiography (see Symptoms and Diagnosis of Heart and Blood Vessel Disorders: Coronary Angiography), x-rays of  arteries are taken after  a radiopaque dye is injected. Coronary angiography,  the most accurate procedure for diagnosing coronary artery disease, may be done when a diagnosis is uncertain. Coronary angiography is commonly used  to help evaluate whether CABG or percutaneous  coronary intervention (PCI) is appropriate. Angiography can also detect spasm of  an artery. A drug that can produce a spasm may be used during angiography if a spasm does not occur. 

In a few people who have typical symptoms of angina and abnormal results on an exercise stress test, coronary angiography does not confirm  the presence of  coronary artery disease. Some of these people have syndrome X, but for most, the source of the symptoms does not involve the heart. 

Continuous ECG monitoring with  a Holter monitor (see Holter Monitor: Continuous ECG Readings ) may detect abnormalities indicating symptomatic or silent ischemia or variant angina (which typically occurs during rest). 

Electron beam computed tomography (CT) scans can detect the amount of calcium deposits in the coronary arteries. The amount of calcium present (the calcium score)  is roughly proportional to the likelihood of the person having angina or  a heart attack. However, because calcium deposits may be present even in people whose arteries are not very narrowed, the score does not reliably predict the need for PCI or CABG. Electron beam CT scans are not recommended for screening all people, in part because it 

exposes people to a significant amount of radiation. However, the test  is often valuable for evaluating people who have  a relatively high risk of death or heart attack. People at risk include those who have diabetes, high  blood pressure,  or both; high cholesterol levels; and abnormal or unclear stress test results. 

Multidetector row CT is a new technique that uses a high speed CT scanner with many small detectors that can accurately identify coronary artery narrowing.  The technique is noninvasive and highly accurate in excluding  coronary artery narrowing as a source of a person's symptoms (particularly in those who were not able to have a stress test or had a stress test that was inconclusive). It can also be used to determine whether a stent or bypass graft is unobstructed, to display cardiac  and coronary venous anatomy, and to assess whether atheromas contain calcium. However,  the technique cannot be used in women who  are pregnant or in people who are unable to hold their breath for 15 to 20 seconds three or four times during  the procedure. Also, because the test does not work well if the heart  is beating fast, people whose heart rate is above 65 beats per minute are given drugs to slow  the heart rate. People who cannot tolerate such drugs or  a low heart rate cannot have the test. People are also exposed to significant amounts of radiation. 

Cardiac magnetic resonance imaging (MRI) is valuable  in evaluating the heart and the large vessels coming from the heart (the aorta and the pulmonary arteries). This technique avoids any radiation exposure. In people with coronary artery disease, MRI may be used to evaluate narrowing of the arteries, measure the  blood flow in  the coronary arteries, and test how well the heart is being supplied with oxygen. MRI can also be used to assess abnormalities of heart wall motion during stress (which may indicate poor blood supply to that area) and whether areas of heart muscle damaged by a heart attack may recover (testing viability).