Pharmacology of coronary vasodilation: a brief review

Successful scintigraphic imaging of coronary artery stenosis is dependent on detecting regional differences (nonhomogeneous distribution) in coronary blood flow that can be induced by physiologic or pharmacologic stress. Table 1 represents a summary of major pharmacologic responses of the heart to the four agents discussed above. Both adenosine and dipyridamole produce superior coronary vasodilation and tend to be preferred for use in single-photon emission computed tomography, whereas dobutamine and arbutamine provoke a marked ischemic response and tend to be preferred for use in echocardiography. Which agent employed remains a judgment of the physician based on known side effects of these agents, the patient's ability to tolerate these side effects, and the nature of the test desired.