The reduction in the coronary circulation through the gradual encroachment on the lumen due to sclerotic changes and, finally, the occlusion of vessels of varying size is primarily responsible for the cardiac disability in disease of the coronary arteries. It is thus important that treatment be directed toward the restoration and maintenance of an effective coronary circulation in this form of cardiac disease. Various remedies, particularly the xanthine derivatives, have been recommended for this purpose. In a previous communication1 experimental data concerning the effectiveness of these preparations were reviewed, and additional observations relative to the dilating action of theophylline ethylenediamine were reported. The latter experiments in our opinion conclusively demonstrated the dilating action of this preparation on the coronary arteries of the dog.
The xanthine derivatives are well known for their diuretic action, and it is generally conceded that theophylline is the most effective of the group. Marvin2