Dear Jo Ann
Coronary artery dominance refers to which artery supplies the posterior part of the heart. In most people it is the right coronary artery. Spasm refers to constriction of the blood vessel, not clot. It can occur due to the catheter itself, especially in the right coronary artery. It can be difficult to differentiate spasm from true disease in the best of hands. This is why tests should only be done when they are truly necessary in the first place, as results can be ambiguous.
I hope this has been useful. I wish you the best of luck. Feel free to write back.
Information provided here is for general purposes only. Specific questions should be addressed to your own doctor. If you would like to make an appointment at the Cleveland Clinic Heart Center, please call 1-800-CCF-CARE or inquire online by using the Heart Center website at www.ccf.org/heartcenter. The Heart Center website contains a directory of the cardiology staff that can be used to select the physician best suited to address your cardiac problem.