[Scintigraphic studies on the influence of coronary-effective drugs on myocardial perfusion during rest]

A hemodynamically effective coronary stenosis causes in the myocardial scintigram a maldistribution of the albumin particles within the corresponding myocardial regions. During exercise or after medicamental vasodilatation the differences in regional myocardial perfusion are amplified. Various scintigraphic pictures can be shown in a double-scintigram investigation using particles labelled by different radionuclides before and after vasodilatation. According to the method of double-scintigraphy the influence of coronary active media (dipyridamol, nitroglycerin, nifedipine) on regional myocardial perfusion is investigated. Because of its long-acting vasodilatation dipyridamol leads to a malperfusion in poststenotic myocardial areas. A similar vasodilatation effect combined with reduced activity in the second perfusion scintigram can be noticed after injection of contrast medium. In contrast to the drugs described above comparable scintigraphic changes after nitroglycerin and nifedipine are due to a different myocardial perfusion pattern, which is only showing a relative malperfusion in the poststenotic regions. At rest neither nitroglycerin nor nifedipine is able to normalize the regional myocardial perfusion.