What Is an Echocardiogram Test? Types and What to Expect

An echocardiogram is an ultrasound of the heart. A small handheld device called a transducer sends sound waves through your chest, and those waves bounce off the heart’s structures to create a moving picture of the organ as it beats. The test is painless, uses no radiation, and typically takes between 30 and 60 minutes. It is the most commonly used imaging test in cardiology, and it comes in several forms depending on what your doctor needs to see.

How It Works

The transducer emits ultrasound waves at frequencies well above what the human ear can detect. As those waves pass through heart muscle, valves, and blood, each tissue reflects the sound back at different rates and intensities. A computer assembles these reflections into a real-time, two-dimensional grayscale image of the beating heart. On top of that, the Doppler effect is used to measure the speed and direction of blood flowing through the chambers and valves, translating the frequency shifts created by moving red blood cells into color-coded or spectral displays on the screen.¹ The result is a detailed, live view of how your heart is pumping, how the valves are opening and closing, and whether blood is moving through the chambers the way it should.

The Standard Transthoracic Echocardiogram

When people say “echocardiogram” without any qualifier, they almost always mean a transthoracic echocardiogram, or TTE. You lie on an exam table, usually on your left side, while a sonographer applies a gel to your chest and presses the transducer against it. The gel helps the sound waves travel smoothly. The sonographer moves the transducer to several positions on your chest to capture different views of the heart from different angles.²

You might feel some pressure when the transducer is pushed firmly against your ribs, but there are no needles, no dye injections, and nothing invasive. You can breathe normally, though the sonographer may occasionally ask you to hold your breath for a few seconds to get a clearer image. Most TTEs wrap up in about 30 to 45 minutes, and you can go about your day immediately afterward. There is no recovery time and no special preparation in most cases.

Transesophageal Echocardiography

Some structures sit in awkward spots that the standard chest-wall approach cannot reach well. Ribs, lungs, and body fat can all get in the way of the ultrasound beam. A transesophageal echocardiogram, or TEE, solves this by placing a small ultrasound probe on the end of a thin, flexible tube that you swallow, much like the scope used in an upper endoscopy. Because the esophagus runs directly behind the heart, the probe gets extremely close to the cardiac structures without any bone or lung tissue in between, producing sharper images.³

TEE is not a routine first-line test. Doctors order it for specific situations: looking for blood clots inside the heart that could cause a stroke, checking for infections on heart valves, evaluating prosthetic valve problems, assessing the aorta, and guiding the surgeon’s view during heart operations or catheter-based procedures.⁴ Your throat is numbed with a spray, and you are usually given a mild sedative through an IV. You will need someone to drive you home afterward, and your throat may feel sore for a few hours.

Stress Echocardiography

A standard echocardiogram shows your heart at rest. That is useful, but some problems only show up when the heart is working hard. A stress echocardiogram captures images of the heart both at rest and during peak exertion. The test looks for areas of heart muscle that do not contract properly under stress, which is a sign that a coronary artery may be partially blocked and not delivering enough blood when demand rises.⁵

If you can exercise, you will typically walk on a treadmill or pedal a stationary bike until your heart rate climbs to a target level. If you cannot exercise because of joint problems, severe shortness of breath, or another limitation, the doctor can use a medication such as dobutamine or dipyridamole to simulate the effect of exercise on the heart. Exercise-based stress echocardiography tends to have the highest accuracy for detecting blocked arteries, with one head-to-head comparison reporting sensitivity around 88% for exercise versus 82% for dobutamine and 74% for dipyridamole.⁶ For most patients, the test takes about an hour including prep and recovery time.

Three-Dimensional Echocardiography

Traditional echocardiograms produce flat, two-dimensional slices of the heart. Three-dimensional echocardiography, or 3DE, uses specialized transducers and software to build a volumetric image that can be rotated and viewed from any angle. This eliminates some of the geometric guesswork inherent in trying to calculate a three-dimensional chamber’s volume from a two-dimensional picture.⁷ 3DE has become especially valuable for planning valve repair surgeries and guiding catheter-based interventions, where the surgeon or interventionalist needs to understand exactly how a valve’s anatomy relates to the structures around it.⁸

From the patient’s perspective, a 3DE exam feels identical to a standard TTE. The transducer may look slightly different, and the scan might take a few extra minutes while the software acquires the volume data, but you are lying on the same table with the same gel on your chest.

Contrast Echocardiography

Sometimes the ultrasound image of the heart chambers is hazy, particularly in patients with larger body habitus or lung disease. Contrast echocardiography sharpens the picture by injecting tiny gas-filled microbubbles into a vein, usually in your arm. These microbubbles are smaller than red blood cells and pass through the lungs into the left side of the heart, where they light up brightly on ultrasound. This makes it much easier to see the inner borders of the heart chambers and spot areas of muscle that are not contracting well.⁹ The microbubbles dissolve harmlessly within minutes, and the gas is exhaled through the lungs. The injection is the only additional step beyond a standard TTE.

What an Echocardiogram Measures

The single most reported number from an echocardiogram is the left ventricular ejection fraction, or EF. It represents the percentage of blood the heart’s main pumping chamber squeezes out with each beat. A normal EF generally falls above 50 percent. This number is central to diagnosing and classifying heart failure, though researchers have increasingly noted that EF alone does not capture the full picture of how well the heart is functioning.¹⁰ Three-dimensional echocardiography has shown excellent agreement with nuclear imaging for measuring EF, providing confidence that the numbers are reliable.¹¹

Beyond EF, echocardiography evaluates heart valve function in detail. Doctors use it to grade how severely a valve is leaking or narrowed, which directly determines whether you need medication, monitoring, or surgery.¹² The test also measures the size of the heart chambers, the thickness of the walls, and whether fluid has accumulated in the sac surrounding the heart. In emergency settings, echocardiography can rapidly identify life-threatening conditions like cardiac tamponade, where fluid around the heart compresses the chambers and prevents them from filling. Telltale signs on the screen include collapse of the right-sided chambers during specific phases of the heartbeat and a swollen vein below the liver that barely changes with breathing.¹³

Strain Imaging and Catching Problems Early

One of the more significant advances in echocardiography over the past two decades is speckle-tracking strain imaging, particularly a measurement called global longitudinal strain, or GLS. Where ejection fraction tells you how much the chamber volume changes, GLS tracks the actual deformation of the heart muscle itself. A 2025 scientific statement from the American Heart Association concluded that GLS offers superior diagnostic and prognostic value across a wide range of heart conditions compared with EF, is highly reproducible, and can detect damage before the ejection fraction starts to drop.¹⁴

This early-detection ability has made strain imaging especially relevant in cancer care. Many chemotherapy drugs can damage the heart, and by the time the EF falls, a meaningful amount of harm has already occurred. Strain imaging can pick up subtle changes in muscle function much earlier, potentially allowing oncologists to adjust treatment before irreversible damage sets in.¹⁵ For heart failure patients more broadly, GLS helps distinguish between different stages and types of dysfunction that EF alone would miss.¹⁶

Fetal and Pediatric Echocardiography

Echocardiography is also the primary way to check a baby’s heart before birth. Fetal echocardiography is typically performed between 18 and 22 weeks of pregnancy, when the heart is large enough to image clearly but early enough for families and doctors to plan if a problem is found.¹⁷ Earlier scans, before 16 weeks, are sometimes done for pregnancies at highest risk. The test itself is similar to a routine pregnancy ultrasound: a transducer is moved across the mother’s abdomen.

Detection rates depend heavily on timing and risk factors. A systematic review and meta-analysis found that the pooled sensitivity for detecting congenital heart defects during the second to third trimester was about 77%, but in high-risk pregnancies, sensitivity climbed to around 85%.¹⁸ One concern in the field is that fetal echocardiography is often reserved for pregnancies with known risk factors, even though congenital heart defects also occur at similar rates in pregnancies without those markers. Some researchers have argued that fetal echocardiography should be offered to all pregnant women as part of routine screening, not just those flagged as high risk.¹⁹

After birth, echocardiography in children requires a somewhat different approach than in adults. Pediatric cardiologists use what is called a segmental analysis, methodically working through the position of the heart in the chest, the arrangement of the internal organs, how the veins connect to the heart chambers, how the chambers connect to each other, and how the great arteries exit the ventricles.²⁰ This step-by-step approach is needed because congenital heart defects can scramble the normal anatomy in ways that adult-focused protocols are not designed to untangle.

Handheld and Point-of-Care Devices

Full-sized echocardiography machines are large, expensive, and tied to a hospital or clinic. Over the past decade, pocket-sized and laptop-sized ultrasound devices have become widely available, allowing doctors to perform a focused cardiac assessment almost anywhere. A systematic review and meta-analysis found that experienced operators using handheld devices could detect reduced heart-pumping function with a pooled sensitivity of about 88% and specificity of about 96%.²¹ They also performed well for identifying enlarged chambers, thickened walls, and abnormal wall motion.

These handheld exams are not meant to replace a full echocardiogram. The image quality is lower, the Doppler capabilities are more limited, and the device captures fewer views. But they can be enormously useful in the emergency department, at the bedside of a critically ill patient, or in a primary-care office where a quick look at the heart could determine whether a patient needs an urgent referral. One study at a tertiary cardiology center found that a handheld device was helpful for assessing chamber size, wall thickness, and valve morphology, but recommended it be used only in combination with a standard exam for definitive diagnosis.²² Think of them as a much more informative version of the stethoscope rather than as a replacement for the full lab workup.

How Echocardiography Compares to MRI and CT

Echocardiography is the workhorse of cardiac imaging, but it is not the only option. Cardiac MRI is generally considered the gold standard for measuring heart muscle strain and for precisely quantifying chamber volumes. However, the complexity and lengthy analysis times of cardiac MRI mean it is used mostly at academic centers and in research settings.²³ Echocardiography, by contrast, is available in virtually every hospital and many outpatient offices, costs far less, and can be done in minutes at the bedside.

There are trade-offs. Standard echocardiography tends to underestimate certain measurements. One study found that TTE underestimated the volume of the left atrium by up to about 32% compared with cardiac MRI and CT.²⁴ For most clinical decisions, this limitation is manageable because doctors are looking at trends over time and at whether values fall into “mild, moderate, or severe” categories rather than chasing exact milliliters. But when precision matters, such as research protocols or borderline surgical decisions, MRI or CT may be preferred. CT also has the advantage of visualizing the coronary arteries themselves, something echocardiography cannot do directly.

The practical upshot for most patients: echocardiography is what you will get first, and for the vast majority of cardiac questions, it provides everything needed. MRI or CT gets ordered when the echo raises questions it cannot fully answer, when image quality is poor, or when the clinical situation demands an especially precise measurement.

Artificial Intelligence in Echocardiography

Reading an echocardiogram well takes years of training, and there is inherent variability between even experienced readers. AI is starting to change that equation. A 2025 study published in JAMA demonstrated a deep learning model capable of performing a comprehensive echocardiographic interpretation across multiple tasks. The model estimated left ventricular ejection fraction with a mean absolute error of only about 4 to 5 percentage points and detected conditions like severe aortic stenosis and right ventricular dysfunction with near-perfect accuracy on external validation data.²⁵

AI tools are also being developed to automate the more tedious parts of echo interpretation, like classifying which view the sonographer captured, outlining the borders of the heart chambers, and flagging abnormalities for the physician to confirm.²⁶ One particularly interesting frontier is using AI to detect heart failure with preserved ejection fraction, a condition that is notoriously difficult to diagnose because the EF looks normal even though the heart is not filling properly. Researchers have trained neural networks on echocardiographic video clips that can distinguish affected patients from healthy controls.²⁷ These tools are still being validated for widespread clinical use, but the trajectory suggests that within the next several years, AI will serve as a second set of eyes for every echocardiogram read.

Echocardiography in Veterinary Medicine

Echocardiography is not limited to human patients. Veterinarians rely on the same technology to diagnose heart disease in animals, particularly cats and dogs. One common application is detecting congestive heart failure in cats with hypertrophic cardiomyopathy, a condition where the heart muscle thickens abnormally. Doppler echocardiographic measurements of how blood flows into the left ventricle and through the pulmonary veins can identify cats that have tipped into heart failure, guiding treatment decisions.²⁸ The principles are the same as in human echocardiography, adapted for the smaller and differently shaped chests of animal patients. If your vet has ever mentioned a heart murmur and recommended an ultrasound, this is the test they mean.