By means of digital image processing, the entire myocardial wall of the left ventricle could be visualized by biplanar angiocardiography in animal experiments using 14 pigs (weight, 16-25 kg). The resulting images of the myocardial wall allowed dimensional measurement by videometry. The muscle volume was computed according to Simpson's rule for end diastole and end systole and compared with postmortem measurements. Replication of the procedure resulted in a 95% confidence interval of +/- 11% (+/- 5.6 ml) at maximum. Comparison with postmortem data showed highly significant correlations of r = 0.894 (end diastole) and r = 0.938 (end systole). This study points out that digital image processing allows a reliable assessment of myocardial volume from routine left ventricular angiocardiography. Besides early clinical applications, the method has been successfully used to visualize nonperfused segments of the myocardial wall in artificial infarction.