An echocardiogram, also known as a cardiac ultrasound, uses standard ultrasound techniques to image two-dimensional slices of the heart. The latest ultrasound systems now employ three-dimensional real-time imaging.

In addition to creating two-dimensional pictures of the cardiovascular system, an echocardiogram can also produce an accurate assessment of the velocity of blood and cardiac tissue at any arbitrary point using pulsed or continuous wave Doppler ultrasound. This allows an assessment of cardiac valve areas and function, any abnormal communications between the left and right side of the heart, any leaking of blood through the valves (valvular regurgitation), and calculation of the cardiac output as well as the ejection fraction.