Learned control of coronary blood flow.

Mongrel dogs with chronically implanted electromagnetic flow probes on the left coronary artery were curarized and trained to decrease coronary blood flow in order to avoid and escape from stress. Each of four animals learned to consistently decrease coronary flow with increasing independence from changes in other cardiovascular dynamics. One animal achieved dramatic decreases suggestive of profound coronary vasoconstriction.

Electrocardiogram during experimental coronary thrombolysis.

The electrocardiogram (ECG) was analyzed before and after enzymatic lysis of an intracoronary thrombus in six closed-chest dogs, and in a control group of five dogs without a thrombus. Thrombolysin (18,000 to 50,000 Merck units in 250 ml of 5% dextrose in water) was infused directly into the anterior descending coronary artery in both groups under the same conditions. Complete recanalization of the obstructed artery was achieved in all cases after development of an occluding thrombus and signs of myocardial infarction.