The purpose of this study was to evaluate the influence of ejection fraction (EF), stroke volume (SV), heart rate, and cardiac output (CO) on coronary artery opacification with 64-slice computed tomography (CT). Sixty patients underwent, retrospectively, electrocardiography-gated 64-slice CT coronary angiography. Left ventricular EF, SV, and CO were calculated with semi-automated software. Attenuation values were measured and contrast-to-noise ratios (CNRs) were calculated in the proximal right coronary artery (RCA) and left main artery (LMA). Mean EF during scanning was 61.5+/-12.4%, SV was 63.2+/-15.6 ml, heart rate was 62.5+/-11.8 beats per minute (bpm), and CO was 3.88+/-1.06 l/min. There was no significant correlation between the EF and heart rate and the attenuation and CNR in either coronary artery. A significant negative correlation was found in both arteries between SV and attenuation (RCA r=-0.26, P<0.05; LMA r=-0.34, P<0.01) and between SV and CNR (RCA r=-0.26, P<0.05; LMA r=-0.26, P<0.05). Similarly, a significant negative correlation was found between the CO and attenuation (RCA r=-0.42, P<0.05; LMA r=-0.56, P<0.001) and between the CO and CNR (RCA r=-0.39, P<0.05; LMA r=-0.44, P<0.001). The actual hemodynamic status of the patient influences the coronary artery opacification with 64-slice CT, in that vessel opacification decreases as SV and CO increase.