 - From Oct 2006 to Jan 2007, CT coronary angiographies of 180 consecutive adult patients, were performed in our hospital using a DSCT scanner. After exclusion of the patients according to the exclusion criteria, totally DSCT coronary angiographies of 133 adult patients N133 were enrolled in this study. Among those 133 patients, including 97 males and 36 females with a mean age of 53.9 ranging from 21 to 78 year old, 50 patients were chronic β-blocker users group 1 while the other 83 patients group 2 were not chronic user of any medication controlling heart rate 