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Several tests are available for detecting and managing coronary heart disease, popularly known as heart disease. Some of these tests are used on a routine basis; others are specialized or high-tech tests performed in a hospital:
Physical Examination
The doctor can diagnose heart disease by doing a physical examination, which includes listening to your heartbeats through a stethoscope. In the presence of heart disease, the heart is likely to produce abnormal sounds due to blockages in the coronary arteries.
Measuring Blood Pressure
Purpose: Measurement of blood pressure.
Check how often: The doctor will check your blood pressure on every visit.
Desirable goal: Less than 120/80 mmHg (as recommended by the National High Blood Pressure Education Program).
Lipid Profile
Type of test: Blood test.
Purpose: Measures cholesterol and other fats in the blood.
Test how often: Once a year
Desirable goals:
| Total cholesterol: | Less than 200 mg/dL (5.2 mmol/L) |
| LDL cholesterol: | Less than 100 mg/dL (2.6 mmol/L) |
| HDL cholesterol: | Greater than 40 mg/dL (1.1 mmol/L) in men |
| Greater than 50 mg/dL(1.3 mmol/L) in women | |
| Triglyceride | Less than 150 mg/dL (3.9 mmol/L) |
C-Reactive Protein Test
C-Reactive protein (CRP), a substance found in the blood, is a sign of inflammation in the body. Current research strongly suggests that inflammation of the coronary arteries, and the resulting raised CRP levels in the blood, are a serious risk factor for heart disease. A laboratory test, namely, hs-CRP test is available that measures CRP in the blood. This test, which is increasingly becoming popular, helps the doctor assess your risk for heart disease.
PLAC Test
The PLAC test is a blood test that measures an enzyme called Lp-PLA2. Raised levels of this enzyme in the blood may indicate inflammation of the coronary arteries associated with heart disease. People who have elevated levels of Lp-PLA2, along with raised LDL cholesterol levels, are at significantly increased risk of having heart disease. This risk is 2 to 3 times higher in these people compared to people with lower values on the PLAC test. This test, when used with other methods of risk assessment, provides additional information about the risks to your heart health.
Electrocardiogram
An electrocardiogram (EKG) traces the electrical impulses produced by the heart on a moving paper strip. The EKG can indicate various heart abnormalities if present, including a previous heart attack and insufficient supply of oxygen and blood to the heart at present.
Heart X-rays
The doctor may order heart X-rays to see its outline. The X-ray can show if the heart is regular in size or of an usual shape. A larger than normal shape of the heart may indicate an abnormality, which needs further investigation.
Plaque Imaging
Piling up of calcium deposits in the coronary arteries is a sign of hardening of the arteries and an increased risk for heart disease. A simple screening tool, known as electron-beam tomography (EBT), is now used that can detect calcium deposits in the coronary arteries long before the symptoms of heart disease actually appear. Such a detection can be a strong motivating factor for people to make necessary lifestyle changes to prevent the actual occurrence of heart disease. The EBT is a noninvasive imaging tool that takes more detailed X-ray pictures than a CT scan; it is currently the most sensitive noninvasive method of detecting coronary artery disease.
Holter Monitoring
AHolter monitor is a small monitor with small rubber pads called electrodes. You wear the monitor on your shoulder with electrodes attached to your body for 24 to 48 hours in a holter monitoring test. The monitor makes a continuous recording of electrical changes in your heart. This record helps the doctor detect heart disease, if present.
Exercise Stress Test
Exercise stress test, also known as exercise tolerance test, aims to see how the heart performs during increased physical activity. Exercise stress test is a combination of exercise, EKG, and blood pressure monitoring. In stress testing, you exercise on a treadmill. After every 2 to 3 minutes, the difficulty level of the treadmill is increased, making you exercise harder. The EKG continuously monitors how well your heart responds to exercise, and blood pressure is taken several times. When the coronary arteries supplying blood to the heart have blockages, blood flow to the heart is obstructed, and the doctor notices abnormal changes in EKG patterns and blood pressure levels. In such a case, you may feel chest pain or unusual shortness of breath (signs that may indicate presence of coronary heart disease). If for some reason such as leg pain or severe weakness you are unable to exercise, the doctor may give you a chemical stress test instead. In a chemical stress test, a drug such as dipyridamole, adenosine, or dobutamine is injected, which has an exercise-like effect on the body.
Nuclear (Thalium) Stress Test
This test is almost the same as the exercise stress test (noted above) except that a minute dose of a radioactive substance is injected into the vein to see how well the blood is flowing to the heart muscle (myocardial perfusion study). Some of the radioactive substances commonly used are thallium-201, sestamibi (Cardiolite), and tetrofosmin (Myoview).
The test is performed in two phases: during exercise (stress) and at rest. In the first phase, you exercise on a treadmill to your maximum fitness level. When blood stimulation is at its peak after exercise or chemical stress, a minute dose of a radioactive substance, thallium for example, is injected into a vein of your arm. At this moment, a special camera, known as the gamma camera, takes pictures of thallium circulating in your blood.
When a coronary artery has a blockage, the blood flow is also reduced to the clogged artery and the amount of injected thallium reaching the heart is not as much as it should be. In the second phase of this test, after you have taken rest for 1 to 2 hours, you will again receive an injection of the radio-active substance. Another set of pictures is taken that will reveal the position of blood flow at rest. The nuclear test gives a good idea of how your heart performs during exercise and at rest.
Images taken from the nuclear stress test provide information about the size of the heart’s chambers, how the heart is pumping blood, whether the heart has any damaged muscle, or the coronary artery has any narrowing or a blockage.
If the exercise stress test or the nuclear stress test indicates a blockage or blockages in the coronary arteries, and the blood flow to the heart is not normal, the doctor may order a more definitive and accurate test called a coronary angiogram (see below).
Nuclear Stress Test
This is a stress test in which a small amount of a radioactive substance will be injected in your vein to see how well the blood is flowing to your heart muscle (myocardial perfusion study). Some of the radioactive substances commonly used are thallium-201, sestamibi (Cardiolite), and tetrofosmin (Myoview).
The test is performed in two phases: during exercise (stress) and at rest. In the first phase, you exercise on a stationary bicycle or a treadmill to your maximum fitness level. If for some reason such as leg pain or severe weakness you are unable to exercise, the doctor will give you a chemical stress test in which a drug such as dipyridamole, adenosine, or dobutamine is injected for stimulating blood flow to your heart. When blood stimulation is peaking after exercise or chemical stress, a minute dose of a radioactive substance, thallium for example, will be injected in your vein. A special camera, known as the gamma camera, will take pictures of thallium circulating in your blood. When a coronary artery has a blockage, the blood flow will also be reduced to the clogged artery and the amount of injected thallium reaching the heart will not be as it should; its flow will also be reduced. In the second phase of this test, after you have taken rest for 1 to 2 hours another set of pictures will be taken, which will reveal the position of blood flow at rest.
If the cardiac stress test or the nuclear stress test is positive, meaning that there is a blockage or blockages in the coronary arteries and the blood flow to the heart is not normal, the doctor may order a more definite and accurate test called the coronary angiogram.
Stress Echocardiography
Stress echocardiography is a combination of exercise stress test (noted above) and ultrasound scan.This is a completely noninvasive procedure that uses ultrasound waves to evaluate blood flow to the heart muscle before and after exercise. To have a stress echocardiogram, first you will take the exercise stress test. After your heart rate reaches a certain level while exercising on the treadmill, the doctor will ask you to lie down on an examination table. Here ultrasound images are taken. This imaging technology is similar to ultrasound scans used to monitor the developing baby during pregnancy.
Electron- Beam Tomography (EBT)
The EBT is a noninvasive imaging tool for looking into the coronary arteries. This test helps detect calcium buildup in the arteries. Piling up of calcium deposits in the coronary arteries contributes to hardening of the arteries, a condition that increases the risk for heart disease in men, women, young, and old. EBT takes detailed pictures of calcium deposits present in the arteries. It is a simple tool that can detect progression of coronary artery calcium (CAC) long before the symptoms of heart disease actually appear. EBT scanning is generally recommended for screening the risk of heart disease in people who do not present its symptoms. However, this test can be included in a comprehensive diagnostic plan for detecting coronary heart disease.
Coronary Angiogram
A coronary angiogram is a special X-ray of the coronary arteries, the arteries that supply blood to the heart. It aims to detect if the coronary arteries are narrowed or fully blocked. The procedure of doing an angiogram is called angiography.
The most common method of performing this procedure is called cardiac catheterization, because it involves the use of a catheter, a thin flexible tube. The doctor inserts the thin catheter into a blood vessel in your leg (thigh) or arm, and advances it to the heart. A contrast material or dye is injected through the catheter to highlight the coronary arteries, because the coronary arteries do not show up on a plain X-ray. Pictures are taken of the contrast dye flowing through the arteries. When the arteries are clear, the dye flows smoothly, but if there are blockages or obstructions, the dye does not go through as it should, and the obstructions show up on the pictures. If a coronary blockage or obstruction is detected during the angiography, the surgeon may clear it through a catheter on the spot, a procedure called angioplasty.
Currently, the cardiac catherization is the most accurate imaging technique and regarded as the “gold” standard for detecting blockages in the coronary arteries.
Several noninvasive imaging techniques for detection of heart disease have emerged in recent years. These include Magnetic Resonance Angiography (MRA), Electron Beam Angiography (EBA), Computed Tomography Angiography (CTA), and Multislice Computed Tomography (MSCT). All these imaging methods are called noninvasive, because they do not require insertion of a catheter to access the heart. However, in all these procedures, a contrast dye is injected into a blood vessel of your arm to highlight the coronary arteries.
[...] Diagnosing Heart Disease [...]
last week our group held a similar discussion on this topic and you show something we have not covered yet, thanks.
- Laura