Factors influencing the diagnostic accuracy of dobutamine stress echocardiography

While Dobutamine stress echocardiography is a well established tool, the range of the diagnostic accuracy found in the literature is rather large. The main reason for this is the fact, that different test protocols were used. Aim of this study was to assess the effects of both addition of atropine as well as consideration of a hyperdynamic response while interpreting the stress echocardiogram on the diagnostic accuracy.

120 consecutive patients were examined and divided into the following groups: A) achieving their age predicted heart rate with dobutamine, B) termination of the test due to ischemia, C1) negative test without reaching the predicted heart rate, and C2) C1 following addition of atropine. All of the echocardiograms were analyzed twice: 1) regarding the lack of a hyperdynamic response to dobutamine as ischemia (Hyper analysis), and 2) ignoring the hypercontractility (Conventional analysis). The accuracy of A and B were 88% and 90% resp. Group C1 had a very poor accuracy of 60%. This rose significantly (p < 0.01) after atropine (C2 = 84%), without leading to an increase of adverse effects. Conventional wallmotion analysis lead to an overall accuracy of 87% (groups A, B, and C2), while Hyper analysis showed an accuracy of 90% (p < 0.01).

To achieve a high accuracy Dobutamine stress echocardiography should always be combined with atropine to reach a target heart rate. The wallmotion analysis should be based on the assumption that a hyperdynamic response to dobutamine is normal, while its lack is indicative of ischemia.