Echocardiography: A look inside your heart

Recently, my cardiologist referred me to the new, modern Cardio-Pulmonary Center of the Cardinal Santos Medical Center, where I underwent a special ultrasound test called echocardiogram. Happily, my results were normal.

Echocardiography, also known as 2D echo, is used to look at the structure and function of your heart. It is today one of the most common tests used to evaluate the heart.

How It Works

Echo uses a wand-like device (transducer) on your chest over your heart to direct ultrasound waves in your heart. The waves bounce (echo) off your heart and are reflected back to the wand through your chest wall. They’re then processed electronically to provide video images of your heart (echocardiogram) in motion. A special type of echo called Doppler ultrasound may also be used. Doppler provides information on blood flow speed and direction.

In a condition called aortic stenosis, the aortic valve doesn’t open as far as it should (please see illustration). This diminishes blood flow from your heart into the aorta and on to the rest of your body, and usually results in a murmur. An echocardiogram can help your doctor determine how fast your blood flows through the valves and blood vessels as one method of detecting heart abnormalities.

Currently, echocardiography provides two-dimensional images, but recent advances are leading to an increased interest in using three-dimensional imaging (such as that provided by Philips’ iE33, hailed as the gold standard in cardiovascular imaging, and now available at the Chinese General Hospital).

Advantages And Disadvantages

The advantages of using echo are numerous. It can be done on people of all ages, even unborn children. Because it’s done from outside the body, it’s virtually pain-free and risk-free. There’s no x-ray exposure and no known risk associated with ultrasound waves. And because the equipment is portable, an echo can be done in your doctor’s office, at your bedside in the hospital, or even during heart surgery to assess results.

One drawback to an echo exam is that it can be relatively expensive for use as a screening tool. Because of this, your doctor can help determine if your symptoms or physical examination findings warrant performing an echo.

In addition, some forms of echo may not provide clear or complete images in certain people, such as those who are very obese or those who have significant obstructive lung (pulmonary) disease. In these situations, a variation of echo may be necessary. In one such specialty technique, called transesophageal echo, a probe with a transducer is placed into your swallowing tube (esophagus) in order to provide better images.

The Heart Of The Issue

The echocardiogram has revolutionized the diagnosis of many heart conditions. One of its primary uses is to evaluate signs and symptoms that suggest certain problems with your heart. Echo is often used to check the heart for causes of a murmur, shortness of breath, chest discomfort, lightheadedness, dizziness or stroke.

Echo is also used to screen for heart complications from other diseases. High blood pressure, diabetes, and some cancers and cancer treatments – such as certain types of chemotherapy – can cause heart problems that may be difficult to detect with an ECG or a physical exam alone.

In addition to diagnosing a number of heart conditions, echo may be used to monitor existing conditions. Your doctor may also use echocardiography as a guide during certain treatment procedures.

Valve Function

Your heart has four valves, which open and close to keep blood flowing in the correct direction through your heart. Any heart valve can be narrowed (stenosis) or leak (regurgitation). All four of the heart valves can be visualized using echocardiography. Echo can be used to identify the structure, thickness, and movement of each heart valve and to check for abnormalities.

When a valve is narrowed, as in aortic stenosis, the heart needs to work harder to pump blood into your organs. Eventually, your heart muscle becomes thicker because it has to pump harder. Defective valves may also leak, allowing some blood to flow backward. Echo helps determine if a valve is severely narrowed or is severely leaking, both of which can necessitate valve repair or replacement. It’s also used to monitor the function of an artificial valve.

Echo can assess the pumping function of your heart. It can help your doctor determine if your heart’s pumping power is normal or reduced to a mild or severe degree. During each heartbeat, the heart contracts and relaxes. When it contracts, it pumps out blood. When it relaxes, it refills with blood. But no matter how forceful the contraction, your heart doesn’t completely empty the pumping chamber (ventricle).

Pump Function

Ejection fraction is the percentage of blood pumped out of a ventricle with each heartbeat. Normal ejection fraction is 50 percent to 70 percent. Reduced ejection often indicates congestive heart failure.

If your ejection function is normal, but the heart’s still pumping abnormally, echo can also be used to check for diastolic dysfunction, a condition in which the ventricle doesn’t relax and fill properly.

Other Heart Conditions

In addition to conditions related to valve and pump functions, there are other numerous heart conditions that echo may be used to diagnose. These include:

• Coronary artery disease. This condition occurs when plaques build up and narrow your coronary arteries, so less blood flows to your heart muscle. Diminished blood flow can cause chest pain (angina), and a sudden, complete blockage can lead to a heart attack.

Echo can identify if and where an area of your heart muscle has been damaged from lack of blood flow by assessing how well that area moves during each heartbeat. Areas of impaired movement are known as regional wall motion abnormalities. These are characteristic of a heart attack or a reduced blood flow (ischemia). Echo is used to evaluate the extent of dysfunction, assess the risk of further damage, and identify any potential complications.

One can also combine an echocardiogram with a cardiac stress test. This is called stress echocardiography and is used to view how your heart works under physical stress.

• Wall thickening. The wall thickness of the left ventricle – the heart’s main pumping chamber – is normally about one centimeter. In people with hypertension, this thickness may increase by 30 percent to 100 percent. This condition, called left ventricular hypertrophy, can interfere with the pumping action of the heart.

Chamber walls also may become severely thickened in a heart muscle disease called hypertrophic cardiomyopathy. Thickened walls increase your risk of heart-related complications and death.

• Excess fluid in the sac surrounding the heart. A membranous sac, called the pericardium surrounds the heart. A small amount of fluid lubricates the pericardium. When excess fluid collects in the pericardium, it’s called pericardial effusion. It’s common after disease or injury involving the heart, and can occur after heart surgery. Retention of too much pericardial fluid can seriously impair heart function.

Echo can help identify the presence of excess fluid and determine its distribution so that your doctor can plan a treatment approach. Echo may also help a doctor visualize fluid as it’s removed with a needle.

• Other conditions. Echo can be used to diagnose numerous other heart conditions, such as a bulge or weakness in the wall of the heart or one of the arteries (aneurysm), congenital heart abnormalities or a hole in the heart (septal defect). It’s also used to check the heart chambers for clots that may occur from a heart attack, and for masses or tumors that can occur from other conditions.

Echocardiography is a major advance in the way doctors look at the structure and function of your heart. You or someone you know may someday benefit from this non-invasive imaging test.