ABSTRACT
This study included 25 patients with mild CAD. A single coronary artery was selectively studied in each patient. From the biplane image, the images that optimized the projection were chosen for analysis. An automatic edge detection routine was utilized to determine vessel diameters which was divided into segments. Results showed that the mean change in vessel diameter was -0.036 + 0.011 mm upon infusion of Ach 10 - 6 M, -0.74 + 0.013 mm upon infusion of Ach 10 - 5 M and -5.86 + 0.91%, respectively, [all means SEM]. These mean value are comprised of individual segments which have disparate response to Ach. A heterogeneous pattern of response was seen in 20 patients at the Ach 10 - 4M, in 16 patients at the 10-5 M and in 18 patients at the 10-6 dose