The aim of this study was to demonstrate an assessment of left internal mammary artery (LIMA) patency and anatomy by standard left ventriculography, and to define a proposal for predicting LIMA function according to left ventriculography outcome. A total of 335 patients with an indication of coronary angiography were included. Standard coronary angiography and left ventriculography were performed initially. Visualization of LIMA occurred in the late phase of ventriculography and the LIMA visualization frame rate was counted for each patient. Then selective LIMA angiography was performed and LIMA diameter, LIMA course and anatomy, and subclavian artery anatomy were noted. Finally, the results of left ventriculography and LIMA angiography were compared by statistical analysis. During left ventriculography, LIMA was visualized in 96.4% of the patients. The mean LIMA visualization frame rate was 53.8 ± 17.7 and the mean LIMA diameter was 2.60 ± 0.36 mm. There was a strong correlation between LIMA visualization frame rate and LIMA diameter, LIMA course, and also asymptomatic subclavian artery disease (P < 0.001). Regression analysis showed that LIMA visualization frame rate is the major independent determinant for LIMA diameter prediction (P < 0.001); LIMA diameter, LIMA course, proximal LIMA side branch, and subclavian artery disease are the major predictors of LIMA visualization on left ventriculography (P < 0.001). LIMA patency and anatomy can be evaluated accurately with a simple method using left ventriculography. Besides direct visualization of LIMA, the visualization frame rate may constitute a reliable parameter for assessing LIMA function. A LIMA visualization frame rate of less than 50 is associated with a healthy and well-sized LIMA.PUBLICATION ABSTRACT