The purpose of this study was to evaluate the relation of transthoracic three- and two-dimensional echocardiographic left ventricular volumetry to cineventriculographic volumetry. Twenty-five patients with distorted left ventricles were included in the study. To demonstrate the impact of acquiring data by rotational scanning, we performed three- and two-dimensional echocardiography in 36 latex ventricles with data acquisition in different areas of the ultrasound sectors. Interobserver and intraobserver variability were calculated to test for reproducibility. The three-dimensional imaging system consisted of a rotation motor device, a transthoracic 2.5 MHz transducer, a conventional ultrasound unit, and a work-station (TomTec) which provides data acquisition, post-processing, and two- or three-dimensional visualization of digitized data. The transducer moved automatically at 2-degree increments with data acquisition at each tomographic level. The mean investigation time for three-dimensional echocardiography was 21 +/- 6 minutes. In the central near field of the transducer, differences from true volumes in latex ventricles were remarkably smaller for three-dimensional compared with two-dimensional echocardiography (root mean square percent error: three-dimensional echocardiography = 5.3% versus two-dimensional echocardiography = 14.6%). In three-dimensional echocardiography, there was considerable overestimation of volumes in the lateral far field (root mean square percent error = 13.2%) of the ultrasound sector. Differences between two-dimensional echocardiographic human left ventricular volumes and cineventriculography increased with larger volumes. In three-dimensional echocardiography the differences remained constant. Interobserver and intraobserver variability is reduced nearly twofold by three-dimensional echocardiography. Three-dimensional echocardiographic volumetry provides fewer discrepancies to cineventriculography and lesser variability than two-dimensional echocardiography. With the use of rotational scanning, the ventricle has to be positioned in the central near field of the transducer.