An "exception proves a rule" only in the realm of the humanities. A scientific rule brooks no exceptions. If these occur, they must be subsumed under a new rule or a modification of the old one.
Exceptions now crowd the rule that angina and myocardial infarction are caused by coronary artery disease. Angina, even myocardial infarction (in a communication in this issue p 804), have been reported in young people whose coronary arteries show no abnormalities on the angiogram or at postmortem examination. Can we find a new rule for these exceptions?
On reviewing a six-year experience with 200 patients who had angina despite normal coronary arteriograms, Kemp et al1 analyzed some current hypotheses. Apparently none passed muster.
The psychosomatic hypothesis fails to explain away the myocardial damage. The coronary artery spasm theory has not been confirmed by evidence that spasms occur spontaneously. Occlusions of small vessels undetectable by
Vaisrub S. Exceptions in Search of a Rule. JAMA. 1974;229(7):821. doi:10.1001/jama.1974.03230450055031