A new theory of infarction-genesis in cats.

It can be shown that a number of substances that are derived from incubation have a good blocking capacity in myocardial infarction. There exists also a natural substance (intrinsic factor, i.f.) which can also block infarction. The same substances also inhibit arrhythmias of ischaemic origin. Thus a common root for myocardial infarction and arrhythmias could be inferred. A new dynamic method (T/2 velocity) was elaborated for evaluating anti-infarction drugs instead of using static T/2 values. Oxidation of i.f. in vitro and in vivo enhances the blocking capacity of artificial drugs reagented previously each other. The natural substance (i.f.) lost its blocking capacity after oxygenation, thus may be unable to compete with the above mentioned artificial substances. Ligation of the coronaries i.e. its myocardial infarction producing effect can also be inhibited by the same substances. No matter how infarction is produced, the same substances can block it. Since after cutting the vagi KCl elicits the same phenomena their reflex origin can be excluded.