What is an Echocardiogram:
An echocardiogram is a test in which ultrasound is used to examine the heart. The equipment is far superior to that used by fishermen. In addition to providing single-dimension images, known as M-mode echo that allows accurate measurement of the heart chambers, the echocardiogram also offers far more sophisticated and advanced imaging. This is known as two-dimensional (2-D) Echo and is capable of displaying a cross-sectional “slice” of the beating heart, including the chambers, valves and the major blood vessels that exit from the left and right ventricle.
An echocardiogram can be obtained in physician’s office or in the hospital. For a resting echocardiogram (in contrast to a stress echo or TEE, discussed elsewhere) no special preparation is necessary. Clothing from the upper body is removed and covered by a gown or sheet to keep you comfortable and maintain the privacy of females. The patient then lies on an examination table or a hospital bed.
Sticky patches or electrodes are attached to the chest and shoulders and connected to electrodes or wires. These help to record the echocardiogram (ECG) during the echocardiography test. The ECG helps in the timing of various cardiac events (filling and emptying of chambers). A colorless gel is then applied to the chest and the echo transducer is placed on top of it. The echo technologist then makes recordings from different parts of the chest to obtain several views of the heart. You may be asked to move from your back and to the side. Instructions may also be given for you to breathe slowly or to hold your breath. This helps in obtaining higher quality pictures. The images are constantly viewed on the monitor. It is also recorded on photographic paper and on videotape. The tape offers a permanent record of the examination and is reviewed by the physician prior to completion of the final report.
What information does Echocardiography and Doppler provide?
Echocardiography is an individual tool in providing the doctor with important information about the following:
Size of chambers of the heart, including the dimensions or volume of the cavity and the thickness o the walls. The appearance of the walls may also help identify certain types of heart disease that predominantly involve the heart muscle. In patients with long standing hypertension or high blood pressure, the test can determine the thickness and “stiffness” of the LV walls. When the LV pumps function is reduced in patients with heart failure, the LV and RV tends to dilate or enlarge, Echocardiography can measure the severity of this enlargement. Serial studies performed on an annual basis can gauge the response of treatment.
Pumping function of the heart can be assessed by echocardiography. One can tell if the pumping power of the heart is normal or reduced to a mild or severe degree. This measure is known as an ejection fraction or EF. A normal EF is around 55 to 65%. Numbers below 45% usually represent some decrease in the pumping strength of the heart, while numbers below 30 to 35% are representative of an important decrease.
Echocardiography can also identify if the heart is pumping poorly due to a condition known as cardiomyopathy (pronounced cardio-myo-puth-e), or if one or more isolated areas have depressed movement (due to prior heart attaks). Thus, echocardiography can assess the pumping ability of each chamber of the heart and also the movement of each visualized wall. The decreased movement, in turn, can be graded from mild to serve. In extreme cases, an area affected by a heart attack may have no movement
Valve Function: Echocardiography identifies the structure, thickness and movement of each heart valve. It can help determine if the valve is normal, scarred from an infection or rheumatic fever, thickened, calcified (loaded with calcium), torn, etc. It can also assess the function of prosthetic or artificial heart valves.
The additional use of Echo Doppler helps to identify abnormal leakage across heart valves and determine their severity. Doppler is also very useful in diagnosing the presence and severity of valve stenosis (pronounced stee-no-sis) or narrowing. Remember, unlike echocardiography, Doppler follows the direction and velocity of blood flow rather than the movement of the valve leaflets or components. Thus, reversed blood direction is seen with leakages while increased forward velocity of flow with a characteristics pattern is noted with leakage while increased forward velocity flow with a characteristic pattern is noted with valve stenosis.
Echocardiography is used to diagnose mitral valve prolapsed (MVP), while Doppler identifies whether it is associated with leakage or regurgitation of the mitral valve (MR). The presence of MR frequently prompts the use of antibiotics prior to any dental or non-sterile surgical procedure. Such action helps reduce the rare complication of valve infection.
Volume status: Low blood pressure can occur in the setting of poor heart function but may also be seen when patient’s have a reduced volume of circulating blood (as seen with dehydration, blood loss, use of diuretics or “water pill.”, etc.). In many cases, the diagnosis can be made on the basis of history, physical examination of problems. Echocardiography may help clarify the confusion. The inferior vena cava (the major vein that returns blood from the lower half of the body to the right atrium) is distended or increased in size in patients with heart failure and reduced in caliber when the blood volume is reduced.
Other Uses: Echocardiography is useful in the diagnosis of fluid in the pericardium (the sac that surrounds the heart). It also det