An echocardiogram, often called an “echo,” is a widely used imaging technique that provides a moving picture of the heart as it beats. This procedure uses high-frequency sound waves to create real-time images of the heart’s interior structures. A small handheld transducer is placed on the chest, transmitting sound waves and capturing the echoes that bounce back from the heart’s tissues. These echoes are processed by a computer to generate a dynamic visualization of the heart’s chambers, walls, and valves. Because the echo is non-invasive and does not use radiation, it serves as a primary, safe diagnostic tool for evaluating cardiac health.
Diagnosing Unexplained Symptoms
A doctor often orders an echocardiogram when a patient presents with symptoms that suggest an underlying heart condition. The test is crucial for investigating the source of complaints like chronic or acute chest pain, especially when other initial tests are inconclusive. It is also commonly ordered to evaluate unexplained shortness of breath (dyspnea), which can be a sign of fluid buildup related to poor heart function.
Another common trigger for ordering this test is the detection of an abnormal heart sound, or murmur, during a physical examination. While some murmurs are harmless, the echo is necessary to determine if the sound is caused by structural damage to a heart valve. Similarly, episodes of unexplained fainting (syncope) or a persistent feeling of irregular heartbeats (palpitations) prompt the use of an echo to visualize the heart’s mechanical activity.
Assessing Structural Integrity and Valve Function
One of the primary functions of the echocardiogram is to provide a detailed, anatomical assessment of the heart’s physical condition. The procedure allows doctors to measure the size and volume of the heart’s four chambers, which is crucial for identifying enlargement or dilatation that occurs in various forms of cardiomyopathy. The thickness of the heart muscle walls, particularly the left ventricle, is also measured to detect conditions like left ventricular hypertrophy, often caused by long-standing high blood pressure.
The echo provides a high-resolution view of the four heart valves—aortic, mitral, tricuspid, and pulmonary—as they open and close. It can identify valve diseases such as stenosis (narrowing that restricts blood flow) or regurgitation (a leak causing blood to flow backward). The test is also invaluable for identifying congenital heart defects, such as holes between the chambers (septal defects). Furthermore, it assesses damage to the heart muscle after a heart attack, which often appears as regional wall motion abnormalities.
Measuring Cardiac Performance and Blood Flow
Beyond structure, the heart ultrasound is a sophisticated tool for quantifying the heart’s functional performance. A key measurement is the Ejection Fraction (EF), which represents the percentage of blood pumped out of the left ventricle with each beat. A normal EF is above 50%, and a low value is a primary indicator used to diagnose and manage heart failure.
The echo uses Doppler technology to measure the velocity and direction of blood flow throughout the heart. This technique uses the principle that sound waves change frequency when reflected off moving objects, allowing flow patterns to be visualized and color-coded on the screen. Doppler data is essential for assessing the severity of valve problems by measuring the speed of blood flow. Additionally, these measurements can estimate pressures within the heart chambers, such as the pulmonary artery systolic pressure, which indicates pressure in the lungs.
Variations of the Procedure
The most common type is the Transthoracic Echocardiogram (TTE), which involves placing the transducer on the chest wall and is entirely non-invasive. This is the standard first-line test for most cardiac evaluations.
When the standard TTE does not provide clear enough images, a Transesophageal Echocardiogram (TEE) may be necessary. For a TEE, a small probe is guided down the esophagus after the patient is sedated, allowing for clearer images because the esophagus lies directly behind the heart.
A third variation is the Stress Echocardiogram, which assesses how the heart functions under physical or chemical stress. The doctor takes images before and immediately after the patient exercises or receives medication that mimics exercise. This helps detect blockages in the coronary arteries that only become apparent when the heart works harder.