Reduced adverse effects with an accelerated dobutamine stress protocol compared with the conventional protocol: a prospective, randomized myocardial perfusion scintigraphy study.

BACKGROUND

Dobutamine (Dob) stress myocardial perfusion scintigraphy (MPS) has been shown to have diagnostic and prognostic value. However, the protocol recommended for Dob-MPS is long and frequently associated with adverse effects. We sought to compare two stress protocols with Dob in patients undergoing MPS.

METHODS AND RESULTS

168 patients undergoing Dob-MPS were consecutively studied. Two protocols were randomly used: progressive doses of Dob (steps of 10 microg/kg/min at 3-min intervals) up to 40 microg/kg/min, aiming at reaching a minimum of 85% of the age-corrected maximal predicted heart rate (HR), possibly adding atropine to maximal Dob dose in case HR was not achieved (conventional protocol) or progressive doses of Dob aiming at the same HR, but adding atropine at the end of the first stage (accelerated protocol). We compared age, gender, coronary risk factors, history of MI or revascularization, Dob infusion and total stress times, maximal HR, percentage of maximal predicted HR, rate-pressure product, ST changes, MPS scores and incidence of adverse effects. In the 84 patients who underwent the accelerated protocol, the incidence of adverse effects was reduced (34.5%) compared to the conventional protocol (54.8%; P < 0.05), as well as Dob infusion duration (508 +/- 130 vs. 715 +/- 142 sec; P < 0.001). We did not observe significant differences between the groups as to age, gender, clinical aspects, maximal HR, percentage of achieved maximal HR, rate-pressure product, ST changes and perfusion scores.

CONCLUSION

Early administration of atropine makes stress faster and reduces incidence of adverse effects, without reducing efficacy towards achieving the proposed goals.