Prospective study of early atropine use in dobutamine stress echocardiography.
OBJECTIVE
Dobutamine stress echocardiography is a time-consuming test, often requiring atropine at the end of the protocol to achieve target heart rate (HR). We examined whether earlier administration of atropine in appropriate patients would shorten test time and increase the likelihood of achieving peak HR.


METHODS
Two hundred and seventy consecutive patients were randomized prospectively to conventional or early atropine protocols. Of these, 120 patients with an inadequate HR response [mid-30 microg/kg/min HR<100 (age <50) or <90 (age >50); or mid-40 microg/kg/min stage HR<120 (age <50) or <110 (age >50)] were included in the analysis. The remaining patients were used in a model to define which patients are likely to require atropine.


RESULTS
The 61 patients receiving early-atropine had decreased test-time relative to the 59 not receiving early-atropine (17:05 vs. 18:24 min:sec, P=0.014) accompanied by a 10% reduction in total dobutamine dose (P=0.008). Their HR at end of 40 microg/kg/min was 123+/-18 vs. 105+/-17 respectively, P<0.0001. Only 7% of the early-atropine group failed to reach target HR vs. 15% not receiving early-atropine. By multivariate analysis, age (P<0.0001), HR at end of 30 microg/kg/min stage (P<0.0001), beta-blocker use (P=0.009) and baseline HR (P=0.04) were predictors of need for atropine.


CONCLUSIONS
Giving atropine early in appropriate patients can reduce test times without an increase in side effects. Our model enables accurate prediction of these patients.
Lessick
J
J
Department of Cardiology, Rambam Medical Center and Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
Mutlak
D
D
Rinkevich
D
D
Markiewicz
W
W
Reisner
S A
SA
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage* / Q000009:adverse effects; D000328:Adult; D000368:Aged; D000465:Algorithms; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000453:epidemiology; D001285:Atropine / Q000008:administration & dosage* / Q000009:adverse effects; D004280:Dobutamine / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D025401:Echocardiography, Stress / Q000379:methods; D023381:Endpoint Determination; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors
D000318:Adrenergic beta-Agonists; D000889:Anti-Arrhythmia Agents; D004280:Dobutamine; D001285:Atropine