Echocardiograms are commonly used in clinical medicine to diagnose valvular disease by measurement of valve velocity and displacement (1), to determine the presence of pericardial effusions (2), and to measure systolic and diastolic left vertricular diameter (3). The latter measurements may be used to calculate ventricular volume, stroke volume, ejection fraction, and cardiac output under certain defined conditions (4). Standard practice for recording echocardiographic images has been to photograph an oscilloscope with a Polaroid camera. More recently, a cathode ray tube oscillograph has been used to make a continuous record of valve motion, pericardium, and the size of intracardiac chambers as the aim of the transducer is varied. Quantitative measurement of size and motion of cardiac structures is performed using pencil and ruler or, in a few cases, using electronic coordinate digitizers and either computers or desk calculators. The information that can be obtained from a standard echocardiogram is thus limited to that which can be obtained from visual impressions and measurements of photo-graphic records.