Pathophysiology of coronary artery spasm.

Coronary arterial measurements were made from cineangiograms in patients with positive and negative ergonovine tests. In those with positive tests, normal segments of arteries adjacent to the site of spasm and arteries without spasm showed no greater sensitivity to ergonovine than arteries from control patients (20 +/- 13% constriction vs 17 +/- 12%, NS). In patients with positive and negative ergonovine tests, constriction was measured at lesion sites after ergonovine and compared with values predicted from a geometric theory. The measured constriction was always greater than predicted in patients with a positive ergonovine test, and frequently less than predicted in patients with a negative test. The increased sensitivity of arteries that show localized vasospasm at lesion sites after ergonovine administration is not explained by geometry alone.