Sensitivity of the dipyridamole test. A placebo-controlled double-blind crossover study

The sensitivity of the dipyridamole test was examined with the double-blind crossover technique in 30 patients with 2 or 3 coronary vessels disease, treatment-refractory stable angina and positive exercise ECG tests. On two successive days, according to a randomized code, patients received either 0.5 mg/kg dipyridamole or a placebo, both given intravenously. The test was judged to be positive if during or immediately after the injection typical angina occurred which regressed after the subsequent intravenous injection of 0.24 g aminophylline within 3 minutes, or if the ECG showed signs of acute ischemia. The test was judged to be questionably positive if the anginal symptoms regressed spontaneously or later than 3 minutes after aminophylline injection. In a total of 13 of 30 patients (43%) the dipyridamole test was positive, while in a further 4 (13%) it was questionably positive. Ischemic repolarization abnormalities occurred in 9 patients; 5 of them also had positive test signs of angina, in 2 each the results were questionably positive or negative. In 13 patients there were neither anginal symptoms nor ECG changes. Thus the dipyridamole test with its low sensitivity is not suitable for the initial routine diagnosis of coronary heart disease.