Comparison of diastolic blood pressure changes with dobutamine and exercise test

A total of 80 patients (44 with stable angina and 36 during coronary angioplasty follow-up) underwent both exercise and dobutamine stress testing within one week. Dobutamine was infused in doses of 5 micrograms.kg-1.min-1, up to 70 every 5 min with blood pressure and electrocardiographic control. Treadmill exercise testing was performed with a maximal, symptom-limited Bruce protocol. Both systolic blood pressure and heart rate increased significantly with dobutamine and exercise, but the increase was higher with exercise (P = 0.00001). Mean blood pressure increased only with exercise, while diastolic blood pressure increased with exercise and decreased with dobutamine (P = 0.00001). A test was positive when either typical angina or an ST segment shift greater than or equal to 1 mm 80 ms after the J point was present. There were 28 positive tests with exercise and 38 with dobutamine, 22 of them coinciding. In 36 patients both tests were negative. The concordance between both tests was 73%. When each test was related to coronary angiography, dobutamine showed greater sensitivity and efficacy than exercise.

a dobutamine stress test induces a positive response in more patients than does an exercise stress test, although the increase in systolic blood pressure and heart rate is greater with exercise. The decrease in diastolic blood pressure with dobutamine probably plays a role in the positive response.