Single Plane Vs Biplane Studies In Coronary Artery Disease

the subject of the SSS will continue to stimulate pooling of our information in this difficult area. To the Editor: In the recent article by Kostuk and associates (Circulation 47: 242, 1973) the value of lateral plane radioisotope angiocardiography in assessing left ventric-ular performance in acute myocardial infarction was presented. This noninvasive technique was shown to be reasonably accurate in reflecting infarct size and subsequent course. Of note is that in attempting to verify the validity of single plane studies in coronary artery disease, a comparison was made of ejection fractions obtained from single plane radioisotope determination versus biplane cineangiograms. In their study, an excellent correlation was obtained with an r value of 0.91 for ejection fractions. Although Sandler and Dodge' have shown the reliability of single plane angiograms in people with diffuse myocardial disease, recent studies2A have suggested that in coronary artery disease, marked discrepancies may exist between single plane and biplane calculations. This is not surprising in that the lateral or RAO projection does not visualize the posterior lateral or anteroseptal areas. As these areas are frequently well preserved, it has been noted that the ejection fraction, as calculated from the lateral or RAO projection, is frequently underestimated. Because of the unpredictability of which walls are involved in the heart of a given patient, there is no way of predicting the accuracy of a single plane study. Moreover, with sequential studies, unpredictable changes in wall segments may occur and further discrepancies or false values introduced. Thus, it would seem that although there is a temptation to use the simplified single plane approach in coronary artery disease, a note of caution should be sounded in regard to the possibility of errors due to the variable segmental involvement so characteristic of coronary artery disease. References 1. SANDLER H, DODGE HT: Use of single plane angiocar-diograms for the calculation of left ventricular volume in man.plane versus single plane left ventriculography in patients with coronary artery disease. 3. GAULT JH, GENTZLER RD, LIEDTKE AJ: Comparison of left ventricular ejection fraction derived from single plane frontal and lateral cineangiograms in patients with previous myocardial infarction. (abstr) Circulation 46 (suppl II): II-154, 1972 4. VOGEL JHK, CORNISH D, MCFADDEN RB: Underestimation of ejection fraction with single plane angiog-raphy in coronary artery disease: Role of bi-plane angiography. his comments. Certainly, we concur that calculations of ejection fraction based on a single plane method should be …