1543 Route 27, Somerset, NJ 08873

18 Centre Drive, Monroe, NJ 08831

 


 

 

Diagnostic Tests
Echocardiogram

Echocardiography (Ultrasound of the Heart)

 

What is it? 
 An echocardiogram is a test that uses high-frequency sound waves (ultrasound) to create an image of the heart (Figure 1).  A Doppler test uses sound waves to measure the speed and direction of blood flow.  By combining these tests, a cardiologist gets useful information about the heart’s anatomy and function. Echocardiography is the most common test used ito diagnose or rule out heart disease and also to follow adults who have already been diagnosed with a heart problem.

 

 

How is it done? 

The ultrasound test is done with your person lying down comfortably on a bed or examination table.

 
  
The test is done by a cardiac sonographer (a technologist with extensive training in ultrasound).  The examiner will put a few stick-on patches called electrodes on for an electrocardiographic (EKG) tracing during the exam.  He or she will also put a small handheld device (called a transducer) on the chest and abdomen.  It sends and receives the sound waves and is connected by a cable to the ultrasound machine (Figure 2).  The ultrasound machine is a computer that converts sound waves to pictures.  A small amount of clear gel is used between the transducer and chest to make sure there is proper contact.  The gel doesn’t stain and is wiped off when the test is over.

The examiner may select and show a variety of pictures on a TV screen.  You’ll be able to see a picture of the beating heart, and you may be able to see and hear the flow of blood.  The picture normally changes when the transducer is moved.  Expect to hear loud sounds from the ultrasound instrument.  Portions of the test may be recorded on videotape or stored as computer files for later measurement, interpretation and storage as part of the patient record.

Echocardiographic examinations take 20 to 30 minutes.  It is important that you remain still to obtain an examination of acceptable quality.

The test does not hurt.  No feeling comes from the sound waves themselves; sometimes the skin feels mildly warm.  Occasionally there’s mild discomfort from the transducer pressing on the skin.
 
Nuclear Stress Test

 
What is a nuclear stress test?

 
thallium stress test
 

This is a type of nuclear scanning test or myocardial perfusion (mi"o-KAR'de-al per-FU'zhun) imaging test. It shows how well blood flows to the heart muscle. It's usually done along with an exercise stress test on a treadmill.

The nuclear stress test is useful to determine:

  • Extent of a coronary artery blockage
  • Prognosis of patients who've suffered a heart attack
  • Effectiveness of cardiac procedures done to improve circulation in coronary arteries
  • Cause(s) of chest pain
  • Level of exercise that a patient can safely perform

When the patient reaches his or her maximum level of exercise, a small amount of a radioactive substance (myoview or sestamibi) will be injected into the bloodstream. Then the patient lies down on a special table under a camera ("gamma camera") that can see the radioactive material and make pictures. The radioactive substance mixes with the blood in the bloodstream and heart's arteries and enters heart muscle cells. If a part of the heart muscle doesn't receive a normal blood supply, less than a normal amount of radioactive material will be in those heart muscle cells.

The first pictures are usually made at rest. The patient then waits for a some time and undergoes the stress portion of the test. The heart is "stressed" during the exercise test — thus the name "stress test." Another series of pictures is made. These show blood flow to the heart muscle after exercise.

What does the nuclear stress test show?

  • If the test is normal during both exercise and rest, then blood flow through the coronary arteries is normal. The coronary arteries supply blood to the heart muscle.
  • If the test shows that perfusion (blood flow) is normal during rest but not during exercise (a perfusion defect), then the heart isn't getting enough blood when it must work harder than normal. This may be due to a blockage in one or more coronary arteries.
  • If the test is abnormal during both exercise and rest, there's limited blood flow to that part of the heart at all times.
  • If no radioactive material is seen in some part of the heart muscle, the cells in this part of the heart are dead from a prior heart attack. (They have become scar tissue.)

What if I can't perform an exercise test?

Sometimes you can't do an exercise test because you're too sick or have physical problems. In this case, a drug such as adenosine is given. This drug increases blood flow to the heart and thus "mimics" an exercise test. Then the nuclear test is given.
 


Copyright:Heart & Vascular Center of New Brunswick, LLC 2007-2008