An echocardiogram uses ultrasound waves to create a moving picture of your heart. A handheld device called a transducer is placed on your chest (or in some cases, guided down your throat), and the sound waves bounce off your heart structures to produce real-time images on a screen. The exam is one of the most common cardiac tests, and the standard version takes about 30 to 40 minutes with no needles, no radiation, and no recovery time.
How the Imaging Works
At the center of the transducer is a piezoelectric crystal. When an electrical current hits the crystal, it vibrates and sends out ultrasound pulses. Those pulses travel through your chest, bounce off heart walls, valves, and blood, then return to the crystal. The returning waves distort the crystal just enough to generate a new electrical signal, which the machine translates into a live image. Each cycle of sending a pulse and listening for its reflection takes roughly one millisecond, so the picture updates fast enough to show your heart beating in real time.
Most exams also use Doppler imaging to measure blood flow. The principle is the same one that makes a siren sound higher-pitched as it approaches and lower as it moves away. By comparing the frequency of the outgoing pulse to the returning echo, the machine calculates how fast blood is moving and in which direction. Color-flow mapping overlays this information onto the image: red typically means blood flowing toward the transducer, blue means it’s flowing away, and a green or mosaic pattern flags turbulent flow, which can indicate a leaking valve.
Types of Echocardiogram
Transthoracic (TTE)
This is the standard exam. You lie on an exam table, usually tilted onto your left side, while a sonographer presses the transducer against your chest in several positions. The transducer moves between four main “windows”: next to the breastbone, near the bottom tip of the heart, just below the ribcage using the liver as a sound window, and at the notch above the breastbone. At each window the sonographer rotates and angles the probe to capture different slices of the heart. A typical TTE takes 30 to 40 minutes, causes no pain, and requires no sedation.
Transesophageal (TEE)
When the standard chest approach can’t get clear images, or when your doctor needs a closer look at structures behind the heart, a TEE may be ordered. Because the esophagus sits directly behind the heart, a small ultrasound probe threaded down the throat can produce much sharper images. You receive a numbing spray to the back of the throat, a bite guard is placed between your teeth, and you’re given sedation through an IV. Once relaxed, you may be asked to swallow as the probe is guided down. The imaging itself usually takes 20 to 30 minutes. Afterward, your throat will feel numb for about an hour, and because of the sedation you’ll need someone to drive you home.
Stress Echocardiogram
A stress echo captures images of your heart both at rest and under exertion to reveal problems that only appear when the heart is working hard. If you’re able to exercise, you’ll walk on a treadmill following a protocol that gradually increases speed and incline. Images must be captured within 60 seconds of peak exercise, so you’ll move quickly from the treadmill back to the exam table. If you can’t exercise, a medication is infused through an IV to make the heart beat faster and harder, simulating the effect of physical activity. The dose is increased every three minutes until your heart rate reaches the target, at which point the sonographer records the stress images.
How to Prepare
For a standard TTE, preparation is minimal. Wear loose, comfortable clothing since you’ll need to remove your shirt or change into a gown. Avoid applying lotion to your chest beforehand, as it can interfere with the transducer’s contact. You can eat and drink normally.
A TEE requires fasting beforehand because of the sedation and the probe passing through your throat. Your care team will give you a specific time to stop eating and drinking, typically several hours before the appointment. You’ll also need to arrange a ride home. For a stress echo, you may be asked to avoid caffeine and certain medications in the hours before the test, and you’ll want to wear shoes you can walk or jog in comfortably.
What Happens Step by Step (Standard TTE)
You’ll change into a gown and lie on an exam table, usually on your left side with your left arm tucked under your head. Small electrode stickers are placed on your chest to monitor your heart rhythm during the scan. The sonographer applies a water-based gel to the transducer, which helps conduct the sound waves.
The exam begins at the parasternal window, with the transducer placed just left of your breastbone in the third or fourth rib space. This produces a long-axis view showing the left ventricle, the aortic valve, and the mitral valve. The sonographer then rotates the probe about 90 degrees to get short-axis cross-sections at multiple levels, sweeping from the base of the heart down to the tip.
Next, the transducer moves to the apical window near the bottom of the heart, usually around the fifth rib space. This view shows all four chambers at once. Small adjustments in angle reveal additional views, including one that adds the aortic valve (sometimes called the “five-chamber” view).
The sonographer then shifts to the subcostal window, placing the probe just below the ribcage. You may be asked to lie flat, bend your knees to relax your abdominal muscles, and hold a breath. This angle is especially useful for imaging the wall between the atria and for measuring the size of the large vein that returns blood to the heart.
Finally, the suprasternal window at the base of the neck captures the aortic arch. Throughout the exam, the sonographer switches between standard two-dimensional imaging and Doppler modes to assess blood flow across each valve. You may hear a whooshing sound when Doppler is active. The entire process is painless, though the pressure of the transducer against your ribs can occasionally feel mildly uncomfortable.
What the Results Measure
The single most important number from an echocardiogram is the ejection fraction, which represents the percentage of blood the left ventricle pumps out with each beat. A normal ejection fraction falls between about 50% and 70%. Mildly reduced function sits in the 41% to 49% range, and 40% or below is considered significantly reduced. This number helps determine whether heart failure is present and, if so, what type.
Beyond ejection fraction, the exam evaluates the size and thickness of each heart chamber, how well the valves open and close, the direction and speed of blood flow, and whether fluid has collected in the sac surrounding the heart. Doppler measurements can detect even small amounts of valve leakage or narrowing that may not cause symptoms yet. The sonographer records dozens of clips and measurements, which a cardiologist then reviews to compile a final report, usually available within a day or two.
After the Exam
If you had a standard TTE, you can wipe off the gel, get dressed, and go about your day immediately. There are no activity restrictions and no lingering effects.
Recovery from a TEE is slightly more involved. The throat numbness from the anesthetic spray typically wears off within an hour, and you shouldn’t eat or drink until it does, to avoid choking. A mild sore throat for the rest of the day is common. Because of the sedation, plan to rest for the remainder of the day and avoid driving or operating machinery. Most people feel completely normal by the following morning.
After a stress echo, your heart rate and blood pressure are monitored for a short period until they return to baseline. If a medication was used to raise your heart rate, its effects wear off within minutes of stopping the infusion. You can typically resume normal activities the same day.