Left ventricular ejection changes obtained from left ventricle roentgenograms were analyzed before and after coronary artery bypass grafting in 22 consecutive patients with chronic obstructive left anterior descending coronary artery disease receiving collaterals before surgical revascularization. The collateral vessels all disappeared after surgical revascularization. After operation, ejection changes of anterobasal, anterolateral and apical walls supplied by the left anterior descending coronary artery improved from 43.6% +/- 9.7% to 48.5% +/- 8.6% (p < 0.05), from 35.2% +/- 10.9% to 39.4% +/- 9.5% (p < 0.05), and from 46.0% +/- 10.6% to 50.0% +/- 8.7% (p < 0.05), respectively. The improvement in left ventricular wall motion did not appear to be related to the extent of preoperative collateralization. Thus, left ventricular wall motion was impaired in the area supplied by collaterals and was improved by myocardial revascularization. These results suggest that coronary blood flow, even through well-developed collaterals, may not be sufficient, which may produce chronic active ischemia and impaired left ventricular wall motion.