Myocardial infarction without coronary occlusion. A study with a new experimental method in sheep.

An experimental method for induction of myocardial infarction in sheep is described. This leads to local infarction without arteriographically demonstrable lesions in the coronary arteries. A 0.95 mm thick thermosonde is introduced into a coronary artery through a catheter. The tip of the thermosonde is heated to 45-65 degrees C for 1-2 min and the thermosonde is then removed. On heating of the tip, infarction occurs instantaneously, as observed both macro- and microscopically and at left ventricular angiography. The thermosonde method described makes it possible to induce myocardial infarction in sheep in a reproducible way and is therefore applicable to studies of the pathogenesis of infarction. This justifies its use in investigations of the effect of myocardial infarction on the anatomy and function of the left ventricle and coronary arteries.