Echocardiograph, by Cambridge Medical Instruments Ltd., England, 1979. The transducer on the patient's chest generates a high-frequency sound wave. The echoes produced by reflection from the heart produce a characteristic trace on the screen. A permanent trace is also produced. Other cardia events such as the electrocardiogram can be recorded simultaneously.

Echocardiography is a bedside technique for examining the heart. In this machine, high frequency ultrasound waves are produced by a transducer placed on the patient’s chest. The waves rebound or echo off the beating heart. These show the shape, size and movement of a heart's chambers and valves. They also show the rate of blood flow through the heart. Physicians examine these records for irregularities that may be a sign of disease. This echocardiograph was made by Cambridge Medical Instruments Limited in England.