Dual-frame image-freezing unit for two-dimensional echocardiography. Preliminary clinical report.

We developed a "dual-frame image-freezing unit", which enables acquisition of two stop-frame images of the two-dimensional echocardiogram at different points within one cardiac cycle. We assessed the clinical usefulness of this unit by estimating the left ventricular ejection fraction with apical biplane two-dimensional echocardiography in 25 patients who underwent left ventricular biplane cineangiography. The unit functioned successfully in all instances. It was much easier to obtain the left ventricular end-diastolic and end-systolic echocardiographic images than to obtain such images using conventional videotape play-back. The quality of the images obtained by this unit was better than those obtained from videotape play-back. The echocardiographic estimates of the left ventricular ejection fraction showed an excellent correlation with estimates obtained by contrast left ventricular cineangiography. We conclude that this dual-frame image-freezing unit can be satisfactorily applied for the assessment of the left ventricular ejection fraction by two-dimensional echocardiography.