Coronary artery spasm and myocardial infarction in the absence of angiographically demonstrable obstructive coronary disease.

Myocardial infarction due to spasm of an "angiographically normal coronary artery" is rare, and its significance as a cause of myocardial infarction in patients without obstructive coronary disease has not been determined. Two patients are described with transmural myocardial infarction, nonobstructive coronary arteries, and suggestive evidence of coronary vasospasm as the cause of infarction. In one patient, angiography was carried out within 7 days of infarction and the documentation of normal coronary arteries argued strongly against a thromboembolic cause for infarction. This patient also had the combination of asthma, hypereosinophilia, and a systemic disease suggesting an immunologic disturbance with increased autoantibody production. A temporal association was noted between the episodes of asthma and those of coronary spasm during exacerbation of the eosinophilia, which raised the speculative issue of "allergic" coronary vasospasm. It is concluded that spasm of a nonobstructed coronary artery may cause transmural myocardial infarction. Further documentation is required in order to place this association in perspective among the other potential cause of infarction in patients with normal coronary artery anatomy.