[Usefulness and safety of dobutamine stress thallium myocardial scintigraphy]

Pharmaceutical stress test is performed for diagnosis of coronary artery disease in patients who can not perform exercise test. We studied whether high dose dobutamine stress test is useful and safe. Subjects consisted of 133 patients (pts) in doubutamine stress test and 45 pts in exercise test. Dobutamine stress test was initiated by 10 micrograms/kg/min, followed by 10 micrograms/kg/min increment every 3 minutes. Maximal doubutamine dose was 40 micrograms/kg/min for 3 minutes. Endpoints of dobutamine stress were as follows: ST depression equal to or more than (> or =) 0.2 mV: 30 pts, > or = 75% predictive maximum heart rate: 20 pts, > or = 20 mmHg systolic blood pressure fallen: 10 pts, 40 micrograms/kg/min for 3 minutes: 10 pts, chest pain: 7 pts, pressure rate product (PRP) > or = 25,000: 1 patient. Side effects of dobutamine stress test were as follows: palpitation: 52%, arrhythmia: 13%, angina and dyspnea: 7%, headache: 6%. These symptoms were disappeared within 2 minutes. One patient, who performed dobutamine test 2 day after PTCA, had myocardial infarction. At peak of dobutamine stress test, systolic blood pressure, heart rate and PRP were increased similar to exercise test. However, diastolic blood pressure was not changed. The concentration at peak of dobutamine was 25.5 +/- 7.8 micrograms/kg/min. The duration of dobutamine stress test was 7.3 +/- 2.3 minutes. The 65 patients (49%) need more than 20 micrograms/kg/min of dobutamine which was maximal loading dose in previous reports. For diagnosis of coronary artery disease, sensitivity was 91% (31/34) and specificity was 70% (7/10). From these data, high dose dobutamine stress test is useful and relatively safe stress method for diagnosis of coronary disease. This stress test would be performed in patients who can not perform exercise test.