Cardiac Ultrasound

An echocardiogram is an ultrasound of the heart. A handheld probe sends sound waves through the chest wall and listens for the echoes that return, and a computer assembles them into moving pictures of the heart as it beats. There is no radiation involved, nothing is injected for a standard study, and it can be repeated as often as needed.

It is the workhorse of cardiac imaging because a single study answers several questions at once: how big the chambers are, how strongly the heart squeezes, whether the valves open and close properly, and whether there is fluid around the heart.

• Ejection fraction — the percentage of blood the left ventricle pumps out with each beat, the standard measure of pumping strength
• Valve function — whether a valve is narrowed (stenosis) or leaking (regurgitation), and how severely
• Chamber size and wall thickness, including thickening from long-standing high blood pressure
• Wall motion — areas that move poorly, which can indicate a previous heart attack or reduced blood flow
• Fluid in the sac around the heart, and estimated pressures in the lungs

Shortness of breath, swelling in the legs, a heart murmur, palpitations, chest pain, atrial fibrillation, or a known valve problem or cardiomyopathy that needs to be followed over time. It is also used to check the heart before and during treatments that can affect it, including some cancer therapies.

A standard echocardiogram takes roughly 30 to 60 minutes. You undress from the waist up, are given a gown and lie on your left side on an exam table. A sonographer places EKG sensors, applies warm gel and moves the probe across several spots on your chest, pressing firmly at times to get a clear window between the ribs — this can feel like steady pressure but should not be painful. You may be asked to hold your breath briefly or roll further onto your side.

Part of the study is often recorded with Doppler, which measures the speed and direction of blood flow and produces a whooshing sound through the machine's speaker. That sound is expected and is not a sign that anything is wrong.

There is no preparation for a standard study and no restrictions afterward. If your images are difficult to obtain — which can happen with lung disease or body habitus — a contrast agent may be given through an IV to outline the heart's borders more clearly.

A stress echocardiogram adds imaging immediately after exercise or medication to compare the heart at rest and under stress. A transesophageal echocardiogram (TEE) takes images from a probe passed into the esophagus under sedation, giving a much closer view of the valves and the left atrial appendage when a standard study cannot answer the question.

A cardiologist reviews the recorded images and measurements rather than reading them live, so results come from your cardiologist rather than from the sonographer performing the study.